tretinoin and Leukemia

Leukemias occur worldwide, but there are important geographic differences in incidences.. Three leukemias with special Asian perspectives, acute promyelocytic leukemia (APL), T-cell large granular lymphocyte (T-LGL) leukemia and NK-cell leukemia.. In APL, China has made contributions in discovering the efficacy of all-trans retinoic acid (ATRA) and arsenic trioxide. Some APL patients are potentially curable after treatment with ATRA or arsenic trioxide as a single agent. Combined treatment of APL with ATRA and arsenic trioxide induces remission with deeper molecular response. An oral formulation of arsenic trioxide is available, making outpatient treatment feasible. Future regimens for APL should examine how ATRA and arsenic trioxide can be optimally combined with other synergistic drugs. Asian patients with T-LGL leukemia present more frequently with pure red cell aplasia, but less frequently with neutropenia, recurrent infection, splenomegaly and rheumatoid arthritis as compared with Western patients. These differences have potential effects on treatment and disease pathogenesis. NK-cell leukemia is rapidly fatal and occurs almost exclusively in Asian and South American patients. Conventional anthracycline-based chemotherapy designed for B-cell lymphomas do not work in NK-cell leukemias. Novel therapeutic approaches targeting cellular signaling pathways or preferentially upregulated genes are needed to improve outcome.

Topics: Arsenic Trioxide; Arsenicals; Asian People; Cell Proliferation; Humans; Leukemia; Leukemia, Large Granular Lymphocytic; Leukemia, Promyelocytic, Acute; Oxides; Recurrence; Tretinoin

Topics: Animals; Antineoplastic Agents; Benzamides; Dasatinib; Disease Models, Animal; History, 19th Century; Humans; Imatinib Mesylate; Leukemia; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Philadelphia Chromosome; Piperazines; Pyrimidines; Thiazoles; Tretinoin

Members of the caudal gene family (in mice and humans: Cdx1, Cdx2, and Cdx4) have been studied during early development as regulators of axial elongation and anteroposterior patterning. In the adult, Cdx1 and Cdx2, but not Cdx4, have been intensively explored for their function in intestinal tissue homeostasis and the pathogenesis of gastrointestinal cancers. Involvement in embryonic hematopoiesis was first demonstrated in zebrafish, where cdx genes render posterior lateral plate mesoderm competent to respond to genes specifying hematopoietic fate, and compound mutations in cdx genes thus result in a bloodless phenotype. Parallel studies performed in zebrafish embryos and murine embryonic stem cells (ESCs) delineate conserved pathways between fish and mammals, corroborating a BMP/Wnt-Cdx-Hox axis during blood development that can be employed to augment derivation of blood progenitors from pluripotent stem cells in vitro. The molecular regulation of Cdx genes appears complex, as more recent data suggest involvement of non-Hox-related mechanisms and the existence of auto- and cross-regulatory loops governed by morphogens. Here, we will review the role of Cdx genes during hematopoietic development by comparing effects in zebrafish and mice and discuss their participation in malignant blood diseases.

Topics: Adult; Adult Stem Cells; Animals; CDX2 Transcription Factor; Genes, Homeobox; Hematopoiesis; Hematopoietic Stem Cells; Homeodomain Proteins; Humans; Leukemia; Mice; Mice, Knockout; Models, Genetic; Multigene Family; Pluripotent Stem Cells; Signal Transduction; Tretinoin; Zebrafish

Transcription factors play essential roles in controlling normal blood development and their alteration leads to abnormalities in cell proliferation, differentiation and survival. In many childhood acute leukemias, transcription factors are altered through chromosomal translocations that change their functional properties resulting in repressed activity or inappropriate activation. The development of therapies that specifically target these molecular abnormalities holds promise for improving the outcome in diseases that remain challenging to treat, such as childhood T-cell acute lymphoblastic leukemia and acute myeloid leukemia, with improved toxicity profiles. All trans-retinoic acid and arsenic trioxide have already demonstrated efficacy in acute promyelocytic leukemia in both adults and children. Newer agents, such as histone deacetylase inhibitors, drugs targeting the NOTCH pathway, and short interfering RNAs have shown encouraging results in pre-clinical studies and are likely to enter the clinical arena in the near future. Through an improved understanding of the pathways and mechanisms underlying the malignant transformation induced by altered transcription factors, new targeted therapies will be designed that should greatly enhance current available treatments.

Topics: Acute Disease; Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Child; DNA Methylation; Drug Delivery Systems; Histone Deacetylase Inhibitors; Humans; Leukemia; Oxides; Transcription Factors; Tretinoin

The rapid rise of chemical biology aimed at studying signaling networks for basic cellular activities using specific, active small molecules as probes has greatly accelerated research on pathological mechanisms and target therapy of diseases. This research is especially important for malignant tumors such as leukemia, a heterogeneous group of hematopoietic malignancies that occurs worldwide. With the use of a chemical approach combined with genetic manipulation, great progress has been achieved over the past few decades on the biological, molecular and cytogenetic aspects of leukemia, and in its diagnosis and therapy. In particular, discoveries of the clinical effectiveness of all-trans retinoic acid and arsenic trioxide in the treatment of acute promyelocytic leukemia and the kinase inhibitors Imatinib and Dasatinib in the treatment of chronic myelogenous leukemia not only make target therapy of leukemia a reality, but also push mechanisms of leukemogenesis and leukemic cell activities forward. This review will outline advances in chemical biology that help our understanding of the molecular mechanisms of cell differentiation and apoptosis induction and target therapy of leukemia.

Topics: Antineoplastic Agents; Apoptosis; Arsenic Trioxide; Arsenicals; Benzamides; Dasatinib; Growth Inhibitors; Humans; Imatinib Mesylate; Leukemia; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Promyelocytic, Acute; Oxides; Piperazines; Protein Kinase Inhibitors; Pyrimidines; Thiazoles; Tretinoin

Leukemia is a group of heterozygous diseases of hematopoietic stem/progenitor cells that involves dynamic change in the genome. Dissection of genetic abnormalities critical to leukemia initiation provides insights into the elusive leukemogenesis, identifies distinct subsets of leukemia and predicts prognosis individually, and can also provide rational therapeutic targets for curative approaches. The past three decades have seen tremendous advances in the analysis of genotype-phenotype connection of leukemia, and in the identification of molecular biomarkers for leukemia subtypes. Intriguingly, differentiation therapy, targeted therapy and chemotherapy have turned several subtypes of leukemia from highly fatal to highly curable. The use of all-trans retinoic acid and arsenic trioxide, which trigger degradation of PML-RARalpha, the causative fusion protein generated by t (15;17) translocation in acute promyelocytic leukemia (APL), has led to a dramatic improvement of APL clinical outcome. Imatinib mesylate/ Gleevec/STI571, which inhibits the tyrosine kinase activity of BCR-ABL oncoprotein, has now become the new gold standard for the treatment of chronic myeloid leukemia. Optimal use of chemotherapeutic agents together with a stringent application of prognostic factors for risk-directed therapy in clinical trials has resulted in a steady improvement in the treatment outcome of acute lymphoblastic leukemia. Hence, the pace of progress extrapolates to a prediction of leukemia control in the twenty-first century.

Topics: Animals; Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Benzamides; Disease Models, Animal; Humans; Imatinib Mesylate; Leukemia; Oxides; Piperazines; Pyrimidines; Tretinoin

To be maximally effective, therapy of cancer must be directed against both the resting stem cells and the proliferating cells of the cancer. The cell populations of both normal and cancer tissues consist of resting stem cells, proliferating transit-amplifying cells, terminally differentiating cells and dying (apoptotic) cells. The difference between normal tissue renewal and growth of cancers is that some of the transit-amplifying cells in the cancer population do not mature into terminally differentiating cells, but instead continue to proliferate and do not die (maturation arrest). Because of this the number of cancer cells increase, whereas the cell population of normal tissues remains a relatively constant. Conventional radiation treatment and chemotherapy kill the actively proliferating transit- amplifying cells of the cancer. Differentiation therapy, using specific targeted inhibitors of activation, effectively induces differentiation of the proliferating transit-amplifying cancer cells. However, even if the proliferating cancer cells are completely inhibited or eliminated, the cancer stem cells may restore the transit-amplifying population, so that clinical remission is usually temporary. The hypothesis presented in this paper is that successful cancer therapy must be directed against both the resting stem cells and the proliferating cells of the cancer. This may be possible if specific stem cell signals are inhibited using gene therapy, while at the same time attacking proliferating cells by conventional radiation treatment or chemotherapy. With advances in approaches using specific inhibitory RNA, such combination therapy may now be possible, but critical problems in delivering the inhibitory effect specifically to the cancer stem cells have yet to be worked out.

Topics: Animals; Breast Neoplasms; Cell Differentiation; Cell Lineage; Cell Proliferation; Embryonal Carcinoma Stem Cells; Female; Genetic Therapy; Humans; Leukemia; Models, Biological; Neoplasms; Neoplastic Stem Cells; RNA Interference; Stem Cells; Teratocarcinoma; Tretinoin

Topics: DNA Methylation; Gene Silencing; Genes, Tumor Suppressor; Histone Deacetylase Inhibitors; Humans; Leukemia; Tretinoin

A series of receptors expressed in the surface of tumor cells, which are able to mediate internalizing effect by specially connecting with corresponding ligands. These receptors are potential targets for drugs combined with conjugates. So the drug-conjugate compounds can be targeted delivery to tumor cells. The folate receptor is a promising target because of its marrow tissue specificity, its overexpression in malignant tissues, especially in myeloid leukemic cells, and its ability to bind and internalize folic acid conjugates. It is a promising potential method to apply folate receptor in the receptor-mediated targeting therapy of leukemic cells. In this review, the biological features of folate receptor, its chromosome location and its interaction with ligands, the distribution characteristics of folate receptor in normal and tumor tissues, especially in myeloid leukemic cells, and progress of research on folate receptor mediated targeting tumor cells, especially leukemic cells were summarized.

Topics: Antineoplastic Agents; Carrier Proteins; Drug Delivery Systems; Folate Receptors, GPI-Anchored; Folic Acid; Humans; Leukemia; Receptors, Cell Surface; Tretinoin; Tumor Cells, Cultured

The network and balance of cytokines is of major importance in maintaining proper homeostasis of hematopoiesis. Abnormalities in this network may result in a variety of blood disorders; however, the role of this network is not clear in leukemia. The use of antineoplastic agents has improved the survival rate of some types of leukemia, and adjunctive therapy with cytokines may be helpful. Chemotherapeutic approaches are no longer the best choice because cytotoxicity may affect normal and leukemic cells, and leukemic cells may develop resistance to the chemotherapeutic agent. Induction of differentiation to a mature phenotype and the control of apoptotic-gene expression have provided other possible alternative therapies. Combined effects of cytokines and vitamin derivatives such as retinoic acid (RA) and 1,25 dihydroxyvitamin D3 (VD3) were found more beneficial than any of these agents individually. These agents exhibit cooperative effects, potentiate each other's effects, or both. Therefore, understanding the hematopoietic actions of these agents, their interactions with their receptors, and their differentiation signaling pathways may result in the design of new therapies. However, the role of cytokines in apoptosis is controversial because in some cases they were found to increase tumor cell resistance to apoptosis-inducing agents. Recent studies in the molecular biology of gene regulation, transcription factors, and repressors have led to new possible approaches such as differentiation therapy for the treatment of leukemia. In addition, the development of drugs that act on the molecular level such as imatinib is just the beginning of a new era in molecular targeted therapy in which the drug acts specifically on the leukemic cell. There are many possible combinations of cytokines, retinoids, and VD3, and perhaps the best therapeutic combination is yet to be described. This minireview is an update on the role of cytokines and the therapeutic potential of combinations with agents such as RA, VD3, and other chemotherapeutic agents.

Topics: Animals; Apoptosis; Calcitriol; Chemotherapy, Adjuvant; Cytokines; Drug Synergism; Hematopoiesis; Humans; Leukemia; Stromal Cells; Tretinoin; Tumor Cells, Cultured

Leukemias are generally chemosensitive, and a majority of leukemia patients undergo remission. However, since chemotherapy after remission generally causes gross systemic toxicity, patients cannot be administered enough anti-cancer drugs to be completely cured; thus, the rate of long-term disease-free survival remains low. Improved survival requires new strategies to prevent relapse. Molecular targeting therapies are remarkably specific and have been demonstrated to cause no gross systemic toxicity. Molecular targeting drugs for leukemia such as all-trans retinoic acid and imatinib are presently being used in clinical settings, and many other molecular targeting drugs are being evaluated in phase I/II clinical trials. This review presents an overview of some of these drugs.

Topics: Benzamides; Drug Delivery Systems; Humans; Imatinib Mesylate; Leukemia; Piperazines; Pyrimidines; Tretinoin

To review novel targeted therapies for the treatment of leukemia.. Professional journals, books, and government publications.. Nonspecific cytotoxic chemotherapeutic agents provide marginal therapeutic benefit and significant toxicity when used in the treatment of leukemia. There is a tremendous need for new therapies with increased efficacy and decreased adverse effects. Advances in molecular science, genetics, and immunology, along with improved laboratory technology, have led to the discovery of unique targets integral to the growth and proliferation of malignant cells which are providing the foundation for the development of a new generation of antitumor agents.. Nurses must be prepared to educate patients, administer novel therapies, and manage side effects.

Topics: Alemtuzumab; Aminoglycosides; Anti-Bacterial Agents; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antibodies, Neoplasm; Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Benzamides; Dose-Response Relationship, Drug; Drug Interactions; Gemtuzumab; Humans; Imatinib Mesylate; Leukemia; Nurse-Patient Relations; Nurse's Role; Oncology Nursing; Oxides; Patient Education as Topic; Piperazines; Prognosis; Pyrimidines; Randomized Controlled Trials as Topic; Tretinoin

Topics: Anticoagulants; Disseminated Intravascular Coagulation; Gabexate; Heparin; Humans; Leukemia; Platelet Transfusion; Serine Proteinase Inhibitors; Thrombocytopenia; Tretinoin; Vitamin K Deficiency

Malignancies in childhood occur with an incidence of 13-14 per 100,000 children under the age of 15 years. Acute lymphoblastic leukaemia with an incidence of 29% is the most common paediatric malignancy, whereas acute myeloid leukaemias account for about 5%. The treatment of acute leukaemias consists of sequential therapy cycles (induction, consolidation, intensification, maintenance therapy) with different cytostatic drugs over a time period of up to 1.5-3 years. Over the last 25 years of clinical trials, a significant rise in the rate of complete remissions as well as an increase in long-term survival has been achieved. Therefore, growing attention is now focused on the long-term effects of antileukaemic treatment. Several cytostatic drugs administered in the treatment of acute leukaemia in childhood are known to cause long-term adverse effects. Anthracyclines may induce chronic cardiotoxicity, alkylating agents are likely to cause gonadal damage and secondary malignancies and the use of glucocorticoids may cause osteonecrosis. Most of the long-term adverse effects have not been analysed systematically. Approaches to minimising long-term adverse effects without jeopardising outcome have included: the design of new drugs such as a liposomal formulation of anthracyclines, the development of anthracycline-derivates with lower toxicity, the development of cardioprotective agents or, more recently, the use of targeted therapy;alternative administration schedules like continuous infusion or timed sequential therapy; and risk group stratification by the monitoring of minimal residual disease. Several attempts have been made to minimise the cardiotoxicity of anthracyclines: decreasing concentrations delivered to the myocardium by either prolonging infusion time or using liposomal formulated anthracyclines or less cardiotoxic analogues, or the additional administration of cardioprotective agents. The advantage of these approaches is still controversial, but there are ongoing clinical trials to evaluate the long-term effects. The use of new diagnostic methods, such as diagnosis of minimal residual disease, which allow reduction or optimisation of dose, offer potential advantages compared with conventional treatment in terms of reducing the risk of severe long-term adverse effects. Most options for minimising long-term adverse effects have resulted from theoretical models and in vitro studies, but only some of the modalities such as the use of dexrazoxane, the con

Topics: Alkylating Agents; Anthracyclines; Antimetabolites; Antineoplastic Agents; Asparaginase; Asparagine; Cardiovascular Diseases; Child; Clinical Trials as Topic; Glucocorticoids; Gonadal Disorders; Humans; Leukemia; Leukemia, Myeloid, Acute; Osteonecrosis; Podophyllotoxin; Polyethylene Glycols; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Tretinoin; Vinca Alkaloids

Recent advances in molecular diagnosis in the hematological laboratory have greatly contributed to the diagnosis and treatment of hematologic malignancies, such as leukemia and lymphoma. The pathogenesis of leukemia and lymphoma has been disclosed by the analyses of genetic abnormalities in patients; abnormal gene expression may induce derangement in the control of cellular proliferation. Based on these genetic abnormalities, gene-targeted therapy has been introduced as a new approach to treating hematologic malignancies. We discuss here the usefulness of the molecular diagnosis in clinical hematology.

Topics: Antineoplastic Agents; Benzamides; Gene Expression Regulation, Leukemic; Gene Targeting; Genetic Therapy; Humans; Imatinib Mesylate; Leukemia; Molecular Diagnostic Techniques; Neoplasm, Residual; Piperazines; Prognosis; Protein-Tyrosine Kinases; Pyrimidines; Tretinoin

In the past two decades, there has been a tremendous increase in our understanding of the molecular mechanism of human leukemias. Leukemias are now recognized as a deregulated state of cell proliferation, differentiation and apoptosis, which is induced by gene alterations, including chromosomal translocations. Many of the mechanisms are potentially exploited as new targets for drug development. All-trans retinoic acid therapy for acute promyelocytic leukemia, which was initially developed as a differentiation therapy in an experienced-based manner, is currently known to be the first successful oncoprotein-directed therapy. Basic and clinical research into ATRA-resistance provides new directions for acute myeloid leukemia therapy. Anti-leukemia therapy will continue to lead the field of chemotherapy in the coming decades.

Topics: Antineoplastic Agents; Drug Resistance; Humans; Leukemia; Leukemia, Promyelocytic, Acute; Recombinant Fusion Proteins; Transcription Factors; Translocation, Genetic; Tretinoin

This review briefly summarizes literature noteworthy in the field of adult acute leukemia published during 1999. The relationship between specific cytogenetic abnormalities and response to treatment was explored within a clinical framework. In particular, detailed analyses of the abnormalities seen in acute promyelocytic leukemia were examined. Two case reports of special interest were published: one shed light on the role of histone deacetylase inhibitors in combination with all-trans retinoic acid, and the other, on the role of granulocyte colony-stimulating factor in this disease. The clinical activity of arsenic was also reported and its mechanism of action explored. In acute lymphoblastic leukemia, attention was focused on occult translocations, and the importance of minimal residual disease was again emphasized. Lastly, results of early clinical trials using an anti-CD19 antibody were reported, with provocative results.

Topics: Acute Disease; Adolescent; Adult; Antibodies, Monoclonal; Antigens, CD19; Antineoplastic Combined Chemotherapy Protocols; Bone Marrow Transplantation; Child; Chromosome Aberrations; Clinical Trials as Topic; Combined Modality Therapy; DNA, Neoplasm; Drug Design; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Humans; Infant; Leukemia; Leukemia, Myeloid; Leukemia, Promyelocytic, Acute; Middle Aged; Multicenter Studies as Topic; Neoplasm Proteins; Neoplasm, Residual; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Prognosis; Randomized Controlled Trials as Topic; Treatment Outcome; Tretinoin

Topics: Antineoplastic Agents; Benzoates; Clinical Trials as Topic; Humans; Informed Consent; International Cooperation; Japan; Leukemia; Tetrahydronaphthalenes; Tretinoin

Topics: Acetylation; Antineoplastic Agents; Cell Differentiation; Chromatin; Chromosomal Proteins, Non-Histone; Core Binding Factor Alpha 2 Subunit; DNA-Binding Proteins; Enzyme Inhibitors; Gene Expression Regulation, Leukemic; Histone Deacetylase Inhibitors; Histone-Lysine N-Methyltransferase; Histones; Humans; Leukemia; Leukemia, Promyelocytic, Acute; Models, Genetic; Myeloid-Lymphoid Leukemia Protein; Neoplasm Proteins; Nucleic Acid Conformation; Nucleosomes; Oncogene Proteins, Fusion; Protein Processing, Post-Translational; Proto-Oncogenes; Recombinant Fusion Proteins; RUNX1 Translocation Partner 1 Protein; Static Electricity; Transcription Factors; Translocation, Genetic; Tretinoin

Topics: CD11 Antigens; Core Binding Factor Alpha 2 Subunit; Drug Resistance, Neoplasm; Fusion Proteins, bcr-abl; HL-60 Cells; Humans; Leukemia; Neoplasm Proteins; Oncogene Proteins, Fusion; Recombinant Fusion Proteins; RNA, Catalytic; RUNX1 Translocation Partner 1 Protein; Transcription Factors; Tretinoin

The outlook for patients with acute promyelocytic leukaemia has improved vastly with the use of all-trans retinoic acid. The development of this therapeutic agent stemmed from the finding that an abnormality of the retinoic acid receptor is involved in this disease. In the search for other molecular abnormalities in the acute leukaemias that might serve as therapeutic targets, the chromosomal translocations associated with this group of disorders have been helpful in indicating where to look for potential cancer genes. Some common signal-transduction pathways through which different such genes act have been identified, and compounds that interfere with these pathways are already being screened for.

Topics: Acute Disease; Chronic Disease; Humans; Leukemia; Leukemia, Promyelocytic, Acute; Molecular Biology; Protein-Tyrosine Kinases; Translocation, Genetic; Tretinoin

The core of the 26S proteasome, the 20S prosome, is a highly organized multi-protein complex found in large amount in malignant cells. Differentiation of several cell lines, including the monoblastic U937 and the lymphoblastoid CCRF-CEM, is accompanied by a general decrease in the prosome concentration when phorbol-myrirtic-acetate (PMA) and retinoic acid plus dihydroxyvitamine D3 (RA+VD) are used. Incubation of U937 cells for three days with PMA or RA+VD causes differentiation, but the resulting patterns of prosome labeling in the cell and on the plasma membrane are not the same. In contrast, the same kind of prosome changes occur in U937 and CCRF-CEM cells when PMA is used as inducer. The intracellular distribution of prosomes is also linked to malignancy and differentiation. Prosomes are found in the nucleus and the cytoplasm of cancer cells; and treatment with RA+VD decreases the prosomes in the nucleus whereas PMA causes various prosome proteins changes. These results indicate that prosomes are important in cell regulation and in the expression of malignancy.

Topics: Cell Differentiation; Cholecalciferol; Cysteine Endopeptidases; Humans; Leukemia; Multienzyme Complexes; Proteasome Endopeptidase Complex; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured

These next years, many anticancer drugs will be available with new mechanism of action. The taxoïd compounds: Taxol and Taxotere have been judged efficous in the treatment of advanced ovary and breast cancers. Also, DNA-Topoisomerase I inhibitors, a new enzyme molecular target, will expand solid tumors therapeutic strategies. The adenosine analogs represent the xnewest advances in hematology: fludarabine becomes the second line treatment for chronic lymphoïd leukemia, cladribine the reference treatment for hairy cell leukemia. At least, all-trans retinoïc acid has changed acute promyelocytic leukemia pronostic by differentiating tumor cells, and open a very new way of cancer treatment. All these agents are the first compounds available, others are still in development. They, all, are benefit of a productive research.

Topics: Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Cladribine; Docetaxel; Humans; Keratolytic Agents; Leukemia; Paclitaxel; Taxoids; Topoisomerase I Inhibitors; Tretinoin; Vidarabine

Topics: Acetamides; Animals; Antineoplastic Agents; Basophils; Carcinogens; Cell Differentiation; Chloroquine; DNA Methylation; Humans; Leukemia; Mice; Tetradecanoylphorbol Acetate; Tretinoin

Topics: Adult; Aged; Bone Marrow Transplantation; Child; Chromosomes, Human, Pair 22; Chromosomes, Human, Pair 9; Cytarabine; Humans; Leukemia; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Promyelocytic, Acute; Middle Aged; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Translocation, Genetic; Tretinoin

Treatment failure in drug sensitive malignancies is a complex phenomenon resulting from both drug resistance and from the rapid regrowth of malignant cells ('regrowth resistance'). Attempts to overcome regrowth resistance during the treatment of the aggressive lymphomas by increasing the frequency of cytotoxic therapy appears to have failed. An alternative approach of significant potential would be to administer biologically active agents to directly slow the regrowth of neoplastic cells between courses of full dose cytotoxic therapy. To facilitate this approach a new system for classifying treatment failure in the leukemias and lymphomas is needed so that the extent of regrowth resistance and the effects of treatment on regrowth resistance can be directly assessed. Accordingly, a new classification system is proposed.

Topics: Antineoplastic Combined Chemotherapy Protocols; Drug Resistance; Genes, myc; Genes, p53; Humans; Interferons; Leukemia; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid, Acute; Lymphoma; Treatment Failure; Tretinoin

Retinoids, including retinoic acid (RA), are naturally occurring and synthetic analogs of vitamin A that inhibit cell growth and induce cell differentiation in many experimental tumor models. Differentiation of the human myelogenous leukemia cell line HL-60 by RA led to the finding that cells from patients with acute promyelocytic leukemia (APL) are terminally differentiated by RA. One mechanism for the activity of RA in a variety of cell types involves the RA nuclear receptors (RA receptors [RARs] and retinoid X receptors), which have specific high-affinity binding sites for RA and some of its metabolites. Other mechanisms may also be involved in RA-induced differentiation. Recent studies suggest that RA acylation (retinoylation) may be involved in the RA induction of differentiation in leukemia cells. Combinations of RA with cyclic adenosine monophosphate (cAMP)-elevating agents led to synergistically induced differentiation of HL-60 cells. The lower doses of RA needed in combination therapy are unlikely to lead to RA resistance, a major limitation of RA therapy in APL. In vitro studies suggest that combinations of RA with either PGE or the butyric acid (BA) prodrug tributyrin (TB) may be useful in differentiation therapy for APL and other malignancies. This is a US government work. There are no restrictions on its use.

Topics: Antineoplastic Combined Chemotherapy Protocols; Butyrates; Butyric Acid; Cell Differentiation; Child; Cyclic AMP; Humans; Leukemia; Leukemia, Promyelocytic, Acute; Prostaglandins E; Tretinoin

The antitumor effect of different retinoids focused attention in the treatment of malignant disorders on different pathways. The therapeutic effect was proved in acute promyelocytic leukaemia, but was limited in juvenile form of chronic myeloid leukaemia and in acute myelomonocytic and monoblastic leukaemia. Combined with different leukostatics, long remission could be achieved. The most important therapeutic pathway is direct growth inhibition with and without cell differentiation. Clinically, retinoids are effective in tumours, like: cutan T-cell lymphoma, mycosis fungoides, Sézary syndrome, oral leukoplakia (prevention of head and neck cancer metastases), variant form of small lung cell carcinoma, oestrogen dependent breast-carcinoma and cervix-carcinoma. The most serious complication of the retinoids' administration is the retinoic acid syndrome which is followed sometimes with thromboembolic events. Retinoids are teratogenic and hepatotoxic.

Topics: Blood Coagulation Disorders; Hematologic Diseases; Hematopoietic System; Humans; Leukemia; Neoplasms; Retinoids; Thromboembolism; Tretinoin

Topics: Carrier Proteins; Cell Differentiation; Humans; Leukemia; Receptors, Retinoic Acid; Tretinoin

Topics: Animals; Antineoplastic Agents; Cell Differentiation; Humans; Leukemia; Leukemia, Experimental; Mice; Rats; Tretinoin

The aim of differentiation therapy is to induce a maturation of the leukemic clone. Various approaches have been used: suppression of proliferation by low dose Ara-C in acute myeloid leukemia (AML); enhancement of differentiation by retinoic acid derivatives in acute promyelocytic leukemia (APL) or by differentiation-inducing factors; modulation of cell metabolism by breaking an autocrine loop in hairy cell leukemia (HCL). In all cases the treatment is given continuously at small doses over a long period of time. The very significant clinical results which have been obtained mainly in APL with all-trans retinoic acid and in HCL with alpha-interferon are briefly discussed.

Topics: Cell Differentiation; Cytarabine; Humans; Interferon Type I; Leukemia; Leukemia, Hairy Cell; Leukemia, Myeloid, Acute; Leukemia, Promyelocytic, Acute; Myelodysplastic Syndromes; Tretinoin

Differentiation therapies try to change the malignant cell in order to acquire a more mature or normal phenotype. Various ways were tested in leukemia: suppression the proliferative pressure by low dose Ara-C, enhancement of the differentiation by retinoic acid derivatives or by differentiation factors, and modulation of the cell metabolism interrupting an autocrine loop (a growth factor and its receptor). The treatment is given continuously at small doses, during a long period of time. In all these cases it seems necessary to tailor the differentiation therapy to each category of leukemia.

Topics: Cell Differentiation; Cell Division; Cytarabine; Humans; Interferon Type I; Leukemia; Leukemia, Hairy Cell; Leukemia, Myeloid, Acute; Leukemia, Promyelocytic, Acute; Myelodysplastic Syndromes; Tretinoin

New light was thrown on the action of tiazofurin in the treatment of end-stage leukemic patients and in leukemic cells in tissue culture. 1. In a population of 21 consecutive patients 50% responded to tiazofurin treatment, confirming the usefulness of this therapy in end-stage leukemia. 2. In leukemic patients treated with tiazofurin and allopurinol reciprocal action was manifested in the increase in hypoxanthine and the decrease in uric acid concentrations in the plasma. On discontinuation of allopurinol, hypoxanthine levels steeply declined but uric acid concentration increased slowly, taking days to reach pretreatment level. 3. With a new and sensitive method the concentration of the active metabolite of tiazofurin, TAD, was measured in the mononuclear cells of tiazofurin-treated patients. Approximately 5 to 13% of the plasma tiazofurin level was observed as TAD in the mononuclear cells. This TAD concentration was sufficient to account for the inhibition of IMP DH in these cells. 4. Tiazofurin or retinoic acid caused differentiation of HL-60 leukemic cells and inhibition of cell proliferation. 5. By treating leukemic cells incubated with tiazofurin or retinoic acid also with guanosine it was elucidated that the mechanism of the two drugs differed since only the tiazofurin effects were counteracted by guanosine. 6. Tiazofurin and retinoic acid together in HL-60 cells provided synergistic impact on differentiation and cytotoxicity. 7. Tiazofurin resulted in down-regulation of the expression of ras and myc oncogenes in three systems: K562 human erythroleukemic cells, rat hepatoma 3924A cells and human HL-60 leukemia cells. 8. Because both tiazofurin and retinoic acid are licensed drugs, their potential use in combination chemotherapy may have clinical relevance in the treatment of end-stage leukemia where our earlier studies have demonstrated the usefulness of tiazofurin.

Topics: Animals; Antineoplastic Agents; Cell Line; Drug Synergism; Gene Expression Regulation, Neoplastic; Humans; Leukemia; Oncogenes; Proto-Oncogenes; Ribavirin; Ribonucleosides; Tretinoin; Tumor Cells, Cultured

The use of chemical agents that induce differentiation of malignant cells to normal cells has held great promise as an adjunct to standard chemotherapy. In vitro data has shown that 13-cis-retinoic acid can differentiate certain leukemia cell lines (e.g., HL-60) into stable granulocyte cells. In this study, oral 13-cis-retinoic acid was administered to four patients with the myelodysplastic syndrome (MDS) and to four patients with acute nonlymphocytic leukemia (ANLL). None of the MDS patients showed an hematologic response to the drug, while three of four ANLL patients responded with normalized peripheral blood counts. The side effects of the drug at 80-120 mg/d (dry skin, cheilitis, epistaxis) were self limiting.

Topics: Acute Disease; Cell Differentiation; Hemoglobins; Humans; Isotretinoin; Leukemia; Middle Aged; Myelodysplastic Syndromes; Tretinoin

Topics: Arachidonic Acid; Arachidonic Acids; Cell Differentiation; Cell Line; Cells, Cultured; Cyclic AMP; Humans; Leukemia; Leukemia, Myeloid, Acute; Lymphokines; Monocytes; Oncogenes; Receptors, Formyl Peptide; Receptors, Immunologic; T-Lymphocytes; Tretinoin

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Cycle; Cell Differentiation; Cell Division; Cell Line; Cytarabine; Humans; Leukemia; Leukemia, Experimental; Tretinoin

Topics: Cell Adhesion; Cell Differentiation; Cell Line; Chemotaxis, Leukocyte; Dimethylformamide; Formazans; Humans; Leukemia; Lymphokines; N-Formylmethionine Leucyl-Phenylalanine; Nitroblue Tetrazolium; Oxidation-Reduction; Receptors, Formyl Peptide; Receptors, Immunologic; Tetradecanoylphorbol Acetate; Tretinoin

As described in this review, both partially purified and recombinant interferons are potent modulators of differentiation in diverse cell culture systems (Table 2). Depending on the target cell, interferon exerts either an inhibitory or an inductive effect on cell differentiation. In certain myeloid leukemic cells, such as HL-60, interferon by itself is growth suppressive but does not induce cell maturation, whereas in combination with inducers of differentiation, such as DMSO, TPA or retinoic acid, interferon potentiates their ability to stimulate differentiation in both sensitive and resistant cell populations (Grant et al., 1982, 1983; Tomida et al., 1982). Interferon also interacts synergistically with phorbol ester tumor promoters in inhibiting melanogenesis in murine B-16 cells (Fisher et al., 1981a, 1984a) and adipocyte formation in 3T3 cells (Cioe et al., 1980), whereas the combination is synergistic in inducing differentiation in human melanoma cells (Fisher et al., 1984b,c). In contrast, interferon and TPA display antagonistic effects on differentiation in human skeletal muscle cultures, i.e. interferon induces and TPA inhibits myogenesis (Fisher et al., 1982, 1983). Recent studies have demonstrated the presence of high affinity saturable cell membrane receptors for mouse and human interferons (Aguet, 1980; Branca and Baglioni, 1981, 1982; Mogensen et al., 1981; Branca et al., 1982; Anderson et al., 1982; Joshi et al., 1982; Faltynek et al., 1983; Yonehara et al., 1983; Langer and Pestka, in preparation). Similarly, specific membrane receptors have been identified for phorbol esters and mezerein (Driedger and Blumberg, 1980; Shoyab and Todaro, 1980; Horowitz et al., 1981; Fisher et al., 1981b). These findings suggest that the plasma membrane may be a primary target for mediating the biochemical effects induced by both interferon and phorbol esters. Although the mechanism by which interferon and phorbol esters transmit the necessary membrane signal(s) required for altering differentiation are not known, a possible component of this transmembrane signaling process may involve changes in the physical dynamics of the plasma membrane. It is therefore of interest that both interferon and TPA induce early changes in the fluidity of the plasma membrane (Fisher et al., 1979, 1981b, 1984d; Castagna et al., 1979; Kuhry et al., 1983).(ABSTRACT TRUNCATED AT 400 WORDS)

Topics: Adipose Tissue; Animals; Cell Differentiation; Cells, Cultured; Dimethyl Sulfoxide; Hematopoiesis; Humans; Interferons; Leukemia; Leukemia, Erythroblastic, Acute; Melanins; Melanoma; Mice; Muscles; Neoplasms; Tetradecanoylphorbol Acetate; Tretinoin

The myelodysplastic syndromes represent a preleukaemic state in which a clonal abnormality of haemopoietic stem cell is characterised by a variety of phenotypic manifestations with varying degrees of ineffective haemopoiesis. This state probably develops as a sequence of events in which the earliest stages may be difficult to detect by conventional pathological techniques. The process is characterised by genetic changes leading to abnormal control of cell proliferation and differentiation. Expansion of an abnormal clone may be related to independence from normal growth factors, insensitivity to normal inhibitory factors, suppression of normal clonal growth, or changes in the immunological or nutritional condition of the host. The haematological picture is of peripheral blood cytopenias: a cellular bone marrow, and functional abnormalities of erythroid, myeloid, and megakaryocytic cells. In most cases marrow cells have an abnormal DNA content, often with disturbances of the cell cycle: an abnormal karyotype is common in premalignant clones. Growth abnormalities of erythroid or granulocyte-macrophage progenitors are common in marrow cultures, and lineage specific surface membrane markers indicate aberrations of differentiation. Progression of the disorder may occur through clonal expansion or through clonal evolution with a greater degree of malignancy. Current attempts to influence abnormal growth and differentiation have had only limited success. Clinical recognition of the syndrome depends on an acute awareness of the signs combined with the identification of clonal and functional abnormalities.

Topics: Anemia, Refractory, with Excess of Blasts; Animals; Antineoplastic Agents; Blood Cell Count; Bone Marrow; Cell Transformation, Neoplastic; Cholecalciferol; Chromosome Aberrations; Chromosome Disorders; Colony-Forming Units Assay; Colony-Stimulating Factors; DNA; Hematopoietic Stem Cells; Humans; Leukemia; Leukemia, Radiation-Induced; Mice; Myelodysplastic Syndromes; Oncogenes; Preleukemia; Rats; Tretinoin

Major advances have been made in the past 10 yr in both the understanding of the biologic characteristics of acute nonlymphocytic leukemia and in the treatment of patients with this disease. Advances in the biologic characteristics include: a better understanding of the nature of leukemic cell proliferation and differentiation; a clearer description of the morphological, histochemical, and ultrastructural characteristics of leukemic cells; a recognition that a high percentage of patients may have specific cytogenetic abnormalities; and a recognition that biochemical differences exist between acute nonlymphocytic leukemia (ANLL) and acute lymphoblastic leukemia (ALL). Today, over 70% of children with ANLL can be induced into a complete remission and over 25% are remaining in a continuous remission for over 2 yr. In spite of these improved results, the best method of extending remissions is unknown. It is unlikely that better results of therapy will be achieved in the future by tailoring the treatment according to the biologic characteristics of the patient, since it appears that ANLL is a heterogeneous group of diseases.

Topics: Acute Disease; Adolescent; Adult; Aged; Bone Marrow Transplantation; Brain Diseases; Cell Aggregation; Cell Differentiation; Cytogenetics; Down Syndrome; Doxorubicin; Granulocytes; Hematopoietic Stem Cells; Humans; Injections, Spinal; Kinetics; Leukemia; Leukocyte Count; Macrophages; Methotrexate; Middle Aged; Mitosis; Phagocytosis; Prognosis; Receptors, Drug; Tretinoin

Topics: Apoptosis; Humans; Leukemia; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Retinoids; Tretinoin

The interaction between activating receptor NKp30 and its major tumor ligand B7-H6 is important for NK cell-mediated tumor rejection. However, the regulation of B7-H6 by tumor therapeutics remains largely unknown. In this study, we investigated the regulation of B7-H6 by all-trans retinoic acid (atRA), a terminal differentiation inducer of tumor cells that is extensively used for clinical leukemia therapy.. We investigated the role of NKp30:B7-H6 axis in NK cell-mediated tumor lysis against leukemia cells and the influence of atRA treatment on the cytotoxicity of NK cells using NK cell lines (NK92 and NKG) and leukemia cell lines (U-937 and THP-1). We evaluated the effect of atRA treatment on the expression of B7-H6 using real-time PCR, flow cytometry and western blotting. We used CRISPR/Cas9 to knockdown B7-H6 expression and siRNA to knockdown c-Myc in U-937 cells to evaluate the role of B7-H6 and c-Myc in atRA-induced tumor resistance against NK cells.. NK cell-mediated U-937 cell lysis was mainly dependent on NKp30/B7-H6 interaction. Blockade of B7-H6 by monoclonal antibody significantly impaired NK cytotoxicity. atRA treatment induced U-937 resistance to NK cell cytotoxicity by reducing B7-H6 expression, and showed no effect on NK cytotoxicity against B7-H6 knockdown U-937 cells. Epigenetic modifications, such as DNA methylation and histone deacetylase (HDAC), were not responsible for atRA-mediated B7-H6 down-regulation as inhibitors of these pathways could not restore B7-H6 mRNA expression. On the other hand, atRA treatment reduced c-Myc expression, which in turn inhibited the transcription of B7-H6 on leukemia cells.. atRA treatment promotes tumor cell resistance against NK cell-mediated lysis by down-regulating B7-H6 expression via the c-Myc signaling pathway, suggesting that more attention needs to be paid to the immunological adverse effects in the clinical use of atRA treatment.

Topics: Humans; Killer Cells, Natural; Leukemia; Natural Cytotoxicity Triggering Receptor 3; Signal Transduction; Tretinoin

All-trans retinoic acid (ATRA), a derivate of vitamin A, has been successfully used as a therapy to induce differentiation in M3 acute promyelocytic leukemia (APML), and has led to marked improvement in outcomes. Previously, attempts to use ATRA in non-APML in the clinic, however, have been underwhelming, likely due to persistent signaling through other oncogenic drivers. Dysregulated JAK/STAT signaling is known to drive several hematologic malignancies, and targeting JAK1 and JAK2 with the JAK1/JAK2 inhibitor ruxolitinib has led to improvement in survival in primary myelofibrosis and alleviation of vasomotor symptoms and splenomegaly in polycythemia vera and myelofibrosis.. While dose-dependent anemia and thrombocytopenia limit the use of JAK2 inhibition, selectively targeting JAK1 has been explored as a means to suppress inflammation and STAT-associated pathologies related to neoplastogenesis. The objective of this study is to employ JAK1 inhibition (JAK1i) in the presence of ATRA as a potential therapy in non-M3 acute myeloid leukemia (AML).. Efficacy of JAK1i using INCB52793 was assessed by changes in cell cycle and apoptosis in treated AML cell lines. Transcriptomic and proteomic analysis evaluated effects of JAK1i. Synergy between JAK1i+ ATRA was assessed in cell lines in vitro while efficacy in vivo was assessed by tumor reduction in MV-4-11 cell line-derived xenografts.. Here we describe novel synergistic activity between JAK1i inhibition and ATRA in non-M3 leukemia. Transcriptomic and proteomic analysis confirmed structural and functional changes related to maturation while in vivo combinatory studies revealed significant decreases in leukemic expansion.. JAK1i+ ATRA lead to decreases in cell cycle followed by myeloid differentiation and cell death in human leukemias. These findings highlight potential uses of ATRA-based differentiation therapy of non-M3 human leukemia.

Topics: Cell Differentiation; Humans; Janus Kinase 1; Leukemia; Leukemia, Myeloid, Acute; Proteomics; STAT5 Transcription Factor; Tretinoin

Leukemia is a commonly seen disease caused by abnormal differentiation of hematopoietic stem cells and blasting in bone marrow. Despite drugs are used to treat the disease clinically, the influence of these drugs on leukemia cells' biomechanical properties, which are closely related to complications like leukostasis or infiltration, is still unclear. Due to non-adherent and viscoelastic nature of leukemia cells, accurate measurement of their elastic modulus is still a challenging issue. In this study, we adopted rate-jump method together with optical tweezers indentation to accurately measure elastic modulus of leukemia cells K562 after phorbol 12-myristate 13-acetate (PMA), all-trans retinoic acid (ATRA), Cytoxan (CTX), and Dexamethasone (DEX) treatment, respectively. We found that compared to control sample, K562 cells treated by PMA showed nearly a threefold increase in elastic modulus. Transwell experiment results suggested that the K562 cells treated with PMA have the lowest migration capability. Besides, it was shown that the cytoskeleton protein gene α-tubulin and vimentin have a significant increase in expression after PMA treatment by qPCR. The results indicate that PMA has a significant influence on protein expression, stiffness, and migration ability of the leukemia cell K562, and may also play an important role in the leukostasis in leukemia.

Topics: Antineoplastic Agents; Biomechanical Phenomena; Cell Movement; Cyclophosphamide; Dexamethasone; Elastic Modulus; Humans; K562 Cells; Leukemia; Tetradecanoylphorbol Acetate; Tretinoin

The NM23 gene is overexpressed in many hematological malignancies and its overexpression predicts poor treatment outcomes. NM23 overexpression is thought to suppress myeloid differentiation of leukemia cells, but the molecular mechanism is unknown. In breast cancer cells, the lysophosphatidic acid (LPA) receptor EDG2/lpa1 was downregulated by NM23-H1 overexpression, and this reciprocal expression pattern was associated with suppressed or induced cell motility/metastasis. Here, we examined the relationship between EDG2 and NM23 expression during myeloid differentiation of leukemia cells. NM23 expression decreased and EDG2 expression increased during all-trans retinoic acid (ATRA)-induced myeloid differentiation of HL-60, NB4, and THP-1 leukemia cells. Moreover, this inverse correlation was more evident when myeloid differentiation was enhanced by ellagic acid, an inhibitor of NM23 activity. In contrast, there was no inverse correlation between EDG2 and NM23 expression during erythroid differentiation of HEL and K562 cells. ATRA plus LPA enhanced the motility of leukemia cells as well as breast cancer cells in an EDG2-dependent manner. These results suggest a common molecular mechanism between myeloid differentiation of leukemia cells and migration of breast cancer cells depending on NM23 and EDG2 expression levels.

Topics: Breast Neoplasms; Cell Differentiation; Down-Regulation; Female; Gene Expression Regulation, Leukemic; HL-60 Cells; Humans; K562 Cells; Leukemia; Lysophospholipids; MCF-7 Cells; Myeloid Cells; Neoplasm Proteins; NM23 Nucleoside Diphosphate Kinases; Receptors, Lysophosphatidic Acid; Tretinoin; U937 Cells; Up-Regulation

Chromatin conformation plays a key role in regulating gene expression and controlling cell differentiation. However, the whole-genome chromatin conformation changes that occur during leukemia cell differentiation are poorly understood. Here, we characterized the changes in chromatin conformation, histone states, chromatin accessibility, and gene expression using an all-trans retinoic acid (ATRA)-induced HL-60 cell differentiation model. The results showed that the boundaries of topological associated domains (TADs) were stable during differentiation; however, the chromatin conformations within several specific TADs were obviously changed. By combining H3K4me3, H3K27ac, and Hi-C signals, we annotated the differential gene-regulatory chromatin interactions upon ATRA induction. The gains and losses of the gene-regulatory chromatin interactions are significantly correlated with gene expression and chromatin accessibility. Finally, we found that the loss of GATA2 expression and DNA binding are crucial for the differentiation process, and changes in the chromatin structure around the GATA2 regulate its expression upon ATRA induction. This study provided both statistical insights and experimental details regarding the relationship between chromatin conformation changes and transcription regulation during leukemia cell differentiation, and the results suggested that the chromatin conformation is a new type of potential drug target for cancer therapy.

Topics: Antineoplastic Agents; Cell Differentiation; Chromatin; GATA2 Transcription Factor; Gene Expression Regulation, Leukemic; HL-60 Cells; Humans; Leukemia; Molecular Conformation; Promoter Regions, Genetic; Promyelocytic Leukemia Zinc Finger Protein; RNA, Messenger; Tretinoin

Recent studies have reported the ectopic expression of olfactory receptors (ORs) in non-olfactory tissues, however, their physiological roles were not well elucidated. ORs are expressed in and function in different types of cancers. Here, we identified that the H3K9me2 levels of several OR promoters decreased during differentiation in the HL-60, human myeloid leukaemia cell line, by all-trans-retinoic acid (ATRA). We found that the differential OR promoters H3K9me2 levels were regulated by G9a and LSD1, resulting in the decrease of ORs transcription during HL-60 differentiation. G9a and LSD1 could regulate the expression of ORs in several non-olfactory cells via the methylation and demethylation of H3K9me2. In addition, we demonstrated that knockdown of OR significantly reduced cell proliferation. Therefore, the epigenetic regulation of ORs transcription is critical for carcinogenesis.

Topics: Cell Differentiation; Cell Line, Tumor; Cell Proliferation; DNA Methylation; Gene Expression Regulation, Leukemic; Gene Knockdown Techniques; Histocompatibility Antigens; Histone Demethylases; Histone-Lysine N-Methyltransferase; Histones; HL-60 Cells; Humans; Leukemia; Receptors, Odorant; Transcription, Genetic; Tretinoin

Progress in the understanding of the molecular mechanism for acute myeloid leukaemia is of great significance to generate new potential targets for treatment. Recent studies showed that HOXA9, a homeodomain-containing transcription factor, is commonly deregulated in acute leukaemia. In this study, we elucidated the direct correlation between HoxA9 expression and progression of leukaemia using 2 different types of leukaemia cells HL-60 and MOLT-3. The HoxA9 expression level was decreased in leukaemia cells with the treatment of all-trans retinoic acid or arsenic trioxide (As

Topics: Animals; Apoptosis; Arsenic Trioxide; Arsenicals; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Down-Regulation; HL-60 Cells; Homeodomain Proteins; Humans; Leukemia; Male; Mice; Mice, Nude; MicroRNAs; Oxides; RNA Interference; RNA, Messenger; Transplantation, Heterologous; Tretinoin

The treatment of acute promyelocytic leukemia (APL) with all-trans retinoic acid (ATRA) induces granulocytic differentiation. This process renders APL cells resistant to cytotoxic chemotherapies. Epigenetic regulators of the histone deacetylases (HDACs) family, which comprise four classes (I-IV), critically control the development and progression of APL. We set out to clarify the parameters that determine the interaction between ATRA and histone deacetylase inhibitors (HDACi). Our assays included drugs against class I HDACs (MS-275, VPA, and FK228), pan-HDACi (LBH589, SAHA), and the novel HDAC6-selective compound Marbostat-100. We demonstrate that ATRA protects APL cells from cytotoxic effects of SAHA, MS-275, and Marbostat-100. However, LBH589 and FK228, which have a superior substrate-inhibitor dissociation constant (Ki) for the class I deacetylases HDAC1, 2, 3, are resistant against ATRA-dependent cytoprotective effects. We further show that HDACi evoke DNA damage, measured as induction of phosphorylated histone H2AX and by the comet assay. The ability of ATRA to protect APL cells from the induction of p-H2AX by HDACi is a readout for the cytoprotective effects of ATRA. Moreover, ATRA increases the fraction of cells in the G1 phase, together with an accumulation of the cyclin-dependent kinase inhibitor p21 and a reduced expression of thymidylate synthase (TdS). In contrast, the ATRA-dependent activation of the transcription factors STAT1, NF-κB, and C/EBP hardly influences the responses of APL cells to HDACi. We conclude that the affinity of HDACi for class I HDACs determines whether such drugs can kill naïve and maturated APL cells.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Benzamides; CCAAT-Enhancer-Binding Proteins; Cell Cycle; Cell Death; Cell Line, Tumor; DNA Damage; Drug Resistance, Neoplasm; Histone Deacetylase Inhibitors; Humans; Leukemia; NF-kappa B; Pyridines; STAT1 Transcription Factor; Tretinoin

The development of small-molecule-based target therapy design for human disease and cancer is object of growing attention. Recently, specific microRNA (miRNA) mimicking compounds able to bind the miRNA-binding domain of Argonaute 2 protein (AGO2) to inhibit miRNA loading and its functional activity were described. Computer-aided molecular design techniques and RNA immunoprecipitation represent suitable approaches to identify and experimentally determine if a compound is able to impair the loading of miRNAs on AGO2 protein. Here, we describe these two methodologies that we recently used to select a specific compound able to interfere with the AGO2 functional activity and able to improve the retinoic acid-dependent myeloid differentiation of leukemic cells.

Topics: Argonaute Proteins; Cell Differentiation; Drug Delivery Systems; Gene Expression Regulation, Leukemic; Humans; Immunoprecipitation; Leukemia; MicroRNAs; Models, Molecular; Small Molecule Libraries; Tretinoin

All-trans retinoic acid, a hydrophobic drug, has become one of the most successful examples of differentiation agents used for treatment of acute promyelocytic leukemia. On the other hand, histone deacetylase inhibitors, such as cholesteryl butyrate, present differentiating activity and.can potentiate action of drugs such as all-trans retinoic acid. Solid lipid nanoparticles represent a promising alternative for administration of hydrophobic drugs such as ATRA. This study aimed to develop, characterize, and evaluate the cytotoxicity of all-trans retinoic acid-loaded solid lipid nanoparticles for leukemia treatment. The influence of in situ formation of an ion pairing between all-trans retinoic acid and lipophilic amines on the characteristics of the particles (size, zeta potential, encapsulation efficiency) was evaluated. Cholesteryl butyrate, a butyric acid donor, was used as a component of the lipid matrix. In vitro activity on cell viability and distribution of cell cycle phases were evaluated for HL-60, Jurkat, and THP-1 cell lines. The encapsulation efficiency of all-trans retinoic acid in cholesteryl butyrate-solid lipid nanoparticles was significantly increased by the presence of the amine. Inhibition of cell viability by all-trans retinoic acid-loaded solid lipid nanoparticles was more pronounced than the free drug. Analysis of the distribution of cell cycle phases also showed increased activity for all-trans retinoic acid-loaded cholesteryl butyrate-solid lipid nanoparticles, with a clear increase in subdiploid DNA content. The ion pair formation in SLN containing cholesteryl butyrate can be explored as a simple and inexpensive strategy to improve the efficacy and bioavail-ability of ATRA in the treatment of the cancer and metabolic diseases in which this retinoid plays an important role.

Topics: Cholesterol Esters; Drug Screening Assays, Antitumor; HL-60 Cells; Humans; Jurkat Cells; Leukemia; Nanoparticles; Tretinoin

The CATS (FAM64A) protein interacts with CALM (PICALM) and the leukemic fusion protein CALM/AF10. CATS is highly expressed in leukemia, lymphoma and tumor cell lines and its protein levels strongly correlates with cellular proliferation in both malignant and normal cells. In order to obtain further insight into CATS function we performed an extensive analysis of CATS expression during differentiation of leukemia cell lines. While CATS expression decreased during erythroid, megakaryocytic and monocytic differentiation, a markedly increase was observed in the ATRA induced granulocytic differentiation. Lentivirus mediated silencing of CATS in U937 cell line resulted in somewhat reduced proliferation, altered cell cycle progression and lower migratory ability in vitro; however was not sufficient to inhibit tumor growth in xenotransplant model. Of note, CATS knockdown resulted in reduced clonogenicity of CATS-silenced cells and reduced expression of the self-renewal gene, GLI-1. Moreover, retroviral mediated overexpression of the murine Cats in primary bone marrow cells lead to decreased colony formation. Although our in vitro data suggests that CATS play a role in cellular processes important for tumorigenesis, such as cell cycle control and clonogenicity, these effects were not observed in vivo.

Topics: Animals; Carrier Proteins; Cell Cycle; Cell Differentiation; Cell Line, Tumor; Cell Movement; Cell Proliferation; Gene Expression Regulation, Neoplastic; Humans; Intracellular Signaling Peptides and Proteins; K562 Cells; Leukemia; Mice, Inbred NOD; Mice, SCID; Nuclear Proteins; RNA Interference; RNAi Therapeutics; Tretinoin; U937 Cells; Xenograft Model Antitumor Assays

While the nucleoporin 98-retinoic acid receptor gamma (NUP98-RARG) is the first RARG fusion protein found in acute leukemia, its roles and the molecular basis in oncogenic transformation are currently unknown. Here, we showed that homodimeric NUP98-RARG not only acquired unique nuclear localization pattern and ability of recruiting both RXRA and wild-type NUP98, but also exhibited similar transcriptional properties as RARA fusions found in acute promyelocytic leukemia (APL). Using murine bone marrow retroviral transduction/transformation assay, we further demonstrated that NUP98-RARG fusion protein had gained transformation ability of primary hematopoietic stem/progenitor cells, which was critically dependent on the C-terminal GLFG domain of NUP98 and the DNA binding domain (DBD) of RARG. In contrast to other NUP98 fusions, cells transformed by the NUP98-RARG fusion were extremely sensitive to all-trans retinoic acid (ATRA) treatment. Interestingly, while pan-RXR agonists, SR11237 and LGD1069 could specifically inhibit NUP98-RARG transformed cells, mutation of the RXR interaction domain in NUP98-RARG had little effect on its transformation, revealing that therapeutic functions of rexinoid can be independent of the direct biochemical interaction between RXR and the fusion. Together, these results indicate that deregulation of the retinoid/rexinoid signaling pathway has a major role and may represent a potential therapeutic target for NUP98-RARG-mediated transformation.

Topics: Animals; Cell Nucleus; Cell Transformation, Neoplastic; Gene Expression Regulation, Leukemic; HEK293 Cells; HeLa Cells; Humans; Leukemia; Mice; Microscopy, Fluorescence; Nuclear Pore Complex Proteins; Protein Binding; Protein Interaction Mapping; Protein Multimerization; Protein Structure, Tertiary; Receptors, Retinoic Acid; Recombinant Fusion Proteins; Retinoic Acid Receptor gamma; Retroviridae; Signal Transduction; Tretinoin

All-trans retinoic acid (ATRA) is one of the most successful examples of differentiation agents and histone deacetylase inhibitors, such as tributyrin (TB), are known for their antitumor activity and potentiating action of drugs, such as ATRA. Nanostructured lipid carriers (NLC) represent a promising alternative to the encapsulation of lipophilic drugs such as ATRA. This study aims to develop, characterize and evaluate the cytotoxicity of ATRA-TB-loaded NLC for cancer treatment.. The influence of in situ formation of an ion pairing between ATRA and a lipophilic amine (benethamine) on the characteristics of NLC (size, zeta potential, encapsulation efficiency) was evaluated. TB, a butyric acid donor, was used as a component of the lipid matrix. In vitro activity on cell viability and distribution of cell cycle phases were evaluated for MCF-7, MDA-MB-231, HL-60 and Jurkat cell lines.. The presence of the amine significantly increased the encapsulation efficiency of ATRA in NLC. Inhibition of cell viability by TB-ATRA-loaded NLC was more pronounced than the free drug. Analysis of the distribution of cell cycle phases also showed increased activity for TB-ATRA-loaded NLC, with the clear effect of cell cycle arrest in G0/G1 phase transition. The presence of TB played an important role in the activity of the formulation.. Taken together, these findings suggest that TB-ATRA-loaded NLC represents a promising alternative to intravenous administration of ATRA in cancer treatment.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Survival; Drug Carriers; Drug Combinations; Female; Histone Deacetylase Inhibitors; HL-60 Cells; Humans; Jurkat Cells; Leukemia; Lipids; MCF-7 Cells; Nanostructures; Tretinoin; Triglycerides

Topics: Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Benzoates; Humans; Leukemia; Oxides; Remission Induction; Tetrahydronaphthalenes; Tretinoin

Let-7c, an intronic microRNA (miRNA) embedded in the long non-coding gene LINC00478, can act as a tumor suppressor by targeting oncogenes. Previous studies indicated that in acute promyelocytic leukemia (APL), a subtype of acute myelogenous leukemia (AML) bearing the leukemia promoting PML/RARα fusion protein, let-7c expression seems to be controlled by the host gene promoter, in which canonical Retinoic Acid Responsive Elements (RAREs) are bound by PML/RARα in an all transretinoic acid (ATRA)-sensitive manner. Here, let-7c transcriptional regulation was further investigated and a novel intronic promoter upstream of the pre-miRNA was identified. This new promoter has transcriptional activity strongly indicating that at least two promoters need to be considered for let-7c transcription: the distal host gene and the proximal intronic promoter. Therefore, epigenetic modifying enzymes and histone acetylation and methylation status were analyzed on both let-7c promoters. It was demonstrated that ATRA treatment leads to let-7c upregulation inducing a more open chromatin conformation of the host gene promoter, with an enrichment of epigenetic marks that correlate with a more active transcriptional state. Conversely, the epigenetic marks on the intronic promoter are not significantly affected by ATRA treatment. Interestingly, in solid tumors such as prostate and lung adenocarcinoma it was found that both host and intronic promoters are functional. These data suggest that while the host gene promoter may control let-7c expression in AML, in a nonleukemic tumor context instead the intronic promoter contributes or preferentially regulates let-7c transcription.. Alternative promoter usage represents a regulatory mechanism of let-7c expression in different tissues. Mol Cancer Res; 12(6); 878-89. ©2014 AACR.

Topics: Acetylation; Animals; Base Sequence; Cell Line, Tumor; Epigenomics; Gene Expression Regulation, Leukemic; Gene Expression Regulation, Neoplastic; Histones; Humans; Introns; Leukemia; Leukemia, Promyelocytic, Acute; MicroRNAs; Molecular Sequence Data; Neoplasms; Promoter Regions, Genetic; Transcription, Genetic; Transfection; Tretinoin

Human UTX, a member of the Jumonji C family of proteins, associates with mixed-lineage leukemia 3/4 complexes. Stimulation with retinoic acid leads to the recruitment of UTX-containing complexes to HOX genes, which results in demethylation of histone H3 lysine 27 and concomitant methylation of histone H3 lysine 4. Here, we show that UTX interacts with the retinoic acid receptor α (RARα) and that this interaction is essential for proper differentiation of leukemic U937 cells in response to retinoic acid. UTX occupies the promoters of several RAR target genes and regulates their transcriptional output by modulating ASH2L complex recruitment. Overexpression of UTX in promyelocytic NB4 cells results in enhanced cellular differentiation upon retinoic acid treatment. Our results show that UTX is important for RAR-mediated transcription and provide insight into the critical role of cross talk between histone H3 lysine 4 methylation and histone H3 lysine 27 demethylation during cellular differentiation.

Topics: Antineoplastic Agents; Cell Differentiation; Cell Line, Tumor; DNA-Binding Proteins; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; HEK293 Cells; Histone Demethylases; Histones; Humans; Leukemia; Nuclear Proteins; Promoter Regions, Genetic; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Transcription Factors; Tretinoin; U937 Cells

Arsenic trioxide (As₂O₃) is used clinically to treat acute promyelocytic leukemia (APL) and has activity in vitro for induction of apoptosis in several solid tumor cell lines. To investigate the potential therapeutic application of As₂O₃ for leukemia, we analyzed the effects of As₂O₃ on the WEHI-3 cells-induced orthotopic leukemia animal model in vivo in this study. We established the WEHI-3 cells leukemia mice through the injection of murine WEHI-3 cells into BALB/c mice, and they were then treated with As₂O₃ (0.9 and 4.5 mg kg⁻¹ ; p.o.) and/or combined with all-trans-retinoic acid (ATRA), (30 mg kg⁻¹ ; i.p.). The results indicated that (1) As₂O₃ alone or As₂O₃ combined with ATRA promoted the total survival rate of leukemia mice and these effects are dose-dependent; (2) As₂O₃ did not affect the body weight but decreased the spleen weight; however, it did not affect liver weight; (3) As₂O₃ alone or As₂O₃ combined with ATRA increased the levels of CD3 and CD19, indicating that the differentiation of T and B cells were promoted; and (4) As₂O₃ alone or As₂O₃ combined with ATRA did not change the levels of Mac-3 and CD11b markers, indicating that the differentiation of the precursor of macrophage were not inhibited. Based on these observations, As₂O₃ alone or As₂O₃ combined with ATRA have efficacious antileukemia activity in WEHI-3 cells leukemia in vivo.

Topics: Animals; Antigens, Differentiation; Arsenic Trioxide; Arsenicals; B-Lymphocytes; Cell Differentiation; Cell Line, Tumor; Leukemia; Leukemia, Experimental; Macrophages; Male; Mice; Mice, Inbred BALB C; Oxides; Spleen; Tretinoin

Topics: Animals; Cell Transformation, Neoplastic; Drug Resistance, Neoplasm; Gene Expression Regulation, Leukemic; Humans; Leukemia; Leukemia, Myeloid, Acute; Mice; Neoplasm Proteins; Trans-Activators; Tretinoin; Tumor Suppressor Proteins

Microtubules are important components of the cell cytoskeleton, participating in protein localization and cell signaling. The capacity of leukemia cells to re-organize their microtubules is considered an integral part of differentiation in these cells in order to become mature granulocytes through treatment with all-trans retinoic acid (ATRA), an established drug for treating acute promyelocytic leukemia. In this study we examined γ-, α- and acetylated-α-tubulin content, their patterns of distribution in the cytoplasm, and the potency of centrosomes in re-organizing microtubules in different stages of ATRA-induced differentiation and apoptosis of the HL-60 cell line. The γ-tubulin content was dramatically increased following differentiation of HL-60 cells, and was then decreased after apoptosis. We also found that γ-tubulin had a diffuse, cytoplasmic pattern following apoptosis compared to the focal, centrosomal accumulation of γ-tubulin in differentiated cells. Differentiated cells had the ability to re-organize their microtubule network following nocodazole challenge testing, whereas undifferentiated cells did not show a similar ability. α-tubulin was more regularly organized in differentiated cells, and did not reveal any specific pattern of polymerization in apoptotic cells. Acetylated-α-tubulin generally followed the same organization patterns after differentiation, as that which occurred for α-tubulin. Our data is suggestive of a centrosomal and organized nucleation pattern of microtubules in HL-60 cells following differentiation, possibly mediated through up-regulation of γ-tubulin.

Topics: Antineoplastic Agents; Apoptosis; Cell Differentiation; Cytoskeleton; HL-60 Cells; Humans; Leukemia; Tretinoin; Tubulin; Up-Regulation

The transcription factor c-Myc strongly stimulates cell proliferation but also regulates apoptosis, senescence, cell competition and cell differentiation, and its elevated activity is a hallmark for human tumorigenesis. c-Myc induces transcription by forming heterodimers with Max and then directly binding DNA at E-box sequences. Conversely, transcription repression depends primarily on the inhibitory interaction of c-Myc/Max with Miz-1 at DNA initiator elements. We recently described a distinct mechanism of c-Myc gene regulation, in which c-Myc interacts with the retinoic acid receptor α (RARα) and is recruited to RAR DNA binding sequences (RAREs). In leukemia cells, this c-Myc/RARα complex functions either as an activator or a repressor of RARα-dependent targets through a phosphorylation switch. Unphosphorylated c-Myc interacts with RARα to repress the expression of RAR targets required for differentiation, thereby aggravating leukemia malignancy. However, if c-Myc is phosphorylated by the kinase Pak2, the c-Myc/RARα complex activates transcription of those same genes to stimulate differentiation, thus reducing tumor burden. Here, we discuss the role of c-Myc in balancing proliferation and differentiation and how modulating this previously unidentified c-Myc activity might provide alternative therapies against leukemia and possibly other types of tumors.

Topics: Cell Differentiation; Cell Proliferation; Epidermis; Gene Expression Regulation, Leukemic; Genes, myc; Genes, Tumor Suppressor; Granulocytes; Humans; Keratinocytes; Leukemia; Multiprotein Complexes; p21-Activated Kinases; Phosphorylation; Protein Interaction Mapping; Proto-Oncogene Proteins c-myc; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Signal Transduction; Stem Cell Niche; Tretinoin

Histone methylation at specific lysine residues is a crucial regulatory process in transcriptional regulation. Using chromatin immunoprecipitation with microarray technology (ChIP-chip) analysis, we found that the H3K9-me2 target gene JAK2 was an important factor during differentiation of the HL-60 promyelocytic leukemia cell line by all-trans-retinoic acid (ATRA) treatment. Here, we report that the H3K9 methyltransferase G9a negatively regulated JAK2 transcription in histone methyltransferase activity and in a YY1-dependent manner during ATRA-mediated leukemia cell differentiation. We found that G9a knockdown repressed ATRA-mediated HL-60 cell differentiation. We demonstrated that G9a interacts with YY1 and is recruited to the JAK2 promoter along with corepressors, including histone deacetylase, that induced H3K9-me2. Repression of JAK2 transcription by G9a decreased H3Y41 phosphorylation and promoted inhibition of the recently identified JAK2-H3Y41P-HP1α pathway-mediated leukemogenesis.

Topics: Adaptor Proteins, Signal Transducing; Cell Differentiation; Chromobox Protein Homolog 5; Gene Expression Regulation, Neoplastic; Histocompatibility Antigens; Histone-Lysine N-Methyltransferase; HL-60 Cells; Humans; Janus Kinase 2; K562 Cells; Leukemia; LIM Domain Proteins; Methylation; Phosphorylation; Promoter Regions, Genetic; Proto-Oncogene Proteins; Transcription, Genetic; Tretinoin; YY1 Transcription Factor

Topics: Antineoplastic Agents; Cell Differentiation; Humans; Leukemia; Tretinoin

A deficient retinoic acid signaling has been suggested to be an important cause of the clinical inefficacy of all-trans retinoic acid (ATRA) therapy in non-promyelocytic (non-PML) forms of acute myeloid leukemia (AML). The general aim of the present work was to explore novel ways to take advantage of the anti-leukemic potential of ATRA, and, specifically, to search for a synergism between ATRA and epigenetic drugs. Because previous reports have found no major influence of ATRA on DNA methylation, we investigated whether ATRA-mediated differentiation of the U937 and HL-60 AML cell lines, both lacking a PML-retinoic acid receptor (RAR) fusion product, is accompanied by early-appearing and weak changes in CpG methylation. We report that in HL-60 cells, by using a highly quantitative analysis of a set of genes found to be abnormally expressed in AML, polymerase chain reaction (PCR)-amplified p16 gene promoter molecules (each with 15 CpG sites), exhibited a CpG methylation level of 0-4% in untreated cells, which increased to 4-21% after treatment with ATRA for seven days. In contrast to HL-60 cells, U937 cells exhibited a very high CpG methylation level in p16, and ATRA did not influence the promoter methylation of this gene. In the total CCGG sites of the genome, analysed using a methylation-sensitive restriction enzyme, CpG methylation was significantly lower in ATRA-treated HL-60 (p<0.01) and U937 cells (p<0.05) than in controls. Taken together, our findings show that ATRA can influence DNA methylation, and suggest that future research should investigate whether epigenetic modulation may evoke a clinical effect of ATRA in leukemia.

Topics: Antineoplastic Agents; Cell Differentiation; CpG Islands; Cyclin-Dependent Kinase Inhibitor p16; DNA Methylation; HL-60 Cells; Humans; Leukemia; Neoplasm Proteins; Oncogene Proteins, Fusion; Polymerase Chain Reaction; Promoter Regions, Genetic; Reverse Transcriptase Polymerase Chain Reaction; Tretinoin; U937 Cells

RIG-G is a retinoic acid- or interferon-induced gene with potential anti-proliferation function. However, the mechanism underlying ATRA-induced RIG-G induction is not completely understood. Here, we demonstrate that ATRA up-regulates the expression of PU.1, which in turn directly binds to the promoter and increases the expression of RIG-G gene. Luciferase reporter assay and electrophoretic mobility shift assay reveal that PU.1 preferentially binds to one of the two putative binding sites on the RIG-G promoter. Moreover, silencing of PU.1 by shRNA markedly inhibited ATRA- but not IFNα-induced expression of RIG-G. These data provide new insight into the mechanism of ATRA-induced RIG-G expression.

Topics: Cell Line, Tumor; Humans; Interferon-alpha; Intracellular Signaling Peptides and Proteins; Leukemia; Promoter Regions, Genetic; Protein Binding; Proto-Oncogene Proteins; RNA, Small Interfering; Trans-Activators; Transcriptional Activation; Tretinoin

RA-inducible gene I (RIG-I/DDX58) has been shown to activate IFN-β promoter stimulator 1 (IPS-1) on recognizing cytoplasmic viral RNAs. It is unclear how RIG-I functions within the IFN and/or RA signaling process in acute myeloid leukemia (AML) cells, however, where obvious RIG-I induction is observed. Here, we show that the RIG-I induction functionally contributes to IFN-α plus RA-triggered growth inhibition of AML cells. Interestingly, although RIG-I induction itself is under the regulation of STAT1, a major IFN intracellular signal mediator, under circumstances in which it does not stimulate IPS-1, it conversely augments STAT1 activation to induce IFN-stimulatory gene expression and inhibit leukemia cell proliferation. Thus, our results unveil a previously undescribed RIG-I activity in regulating the cellular proliferation of leukemia cells via STAT1, which is independent of its classic role of sensing viral invasion to trigger type I IFN transcription.

Topics: Cell Proliferation; DEAD Box Protein 58; DEAD-box RNA Helicases; Gene Expression Regulation; Humans; Leukemia; Receptors, Immunologic; STAT1 Transcription Factor; Tretinoin; U937 Cells

ATRA and a synthetic RAR agonist tamibarotene (Am80) induce granulocytic differentiation of human acute leukemia HL-60 cells and have been used in antineoplastic therapy. ATRA induces CD38 antigen during HL-60 cell differentiation, which interacts with CD31 antigen on the vascular EC surface and may induce disadvantages in the therapy. We here examined the mechanisms of the ATRA-mediated CD38 induction and compared the difference between ATRA- and tamibarotene-mediated induction. Tamibarotene-induced HL-60 cell adhesion to ECs was 38% lower than ATRA, and NB4 cell adhesion to ECs by tamibarotene was equivalent to ATRA, which induced CD38 gene transcription biphasically in HL-60 cells, the early-phase induction via DR-RARE containing intron 1, and the delayed-phase induction via RARE lacking the 5'-flanking region. In contrast to ATRA, tamibarotene induced only the early-phase induction, resulting in its lower CD38 induction than ATRA. A PKCδ inhibitor, rottlerin, and siRNA-mediated PKCδ knockdown suppressed the ATRA-induced CD38 promoter activity of the 5'-flanking region, whereas a RAR antagonist, LE540, or RAR knockdown did not affect it. Cycloheximide and rottlerin suppressed the delayed-phase induction of CD38 expression by ATRA but did not affect the early-phase induction. Moreover, ATRA, but not tamibarotene, induced PKCδ expression without affecting its mRNA stability. The diminished effect of tamibarotene on CD38-mediated HL-60 cell adhesion to ECs compared with ATRA is likely a result of the lack of its delayed-phase induction of CD38 expression, which may be advantageous in antineoplastic therapy.

Topics: ADP-ribosyl Cyclase 1; Benzoates; Cell Adhesion; Endothelial Cells; Gene Expression Regulation, Neoplastic; HL-60 Cells; Humans; Leukemia; Protein Kinase C-delta; Retinoids; Tetrahydronaphthalenes; Tretinoin

Topics: ADP-ribosyl Cyclase 1; Benzoates; Gene Expression Regulation, Neoplastic; Humans; Leukemia; Tetrahydronaphthalenes; Tretinoin

miR-15a and miR-16-1 (miR-15a/16-1) have been implicated in apoptosis, cell cycle regulation and chemosensitivity of tumor cells, but little is known about the role of miR-15a/16-1 in the differentiation of leukemic cells. In this study, we found that the expression level of miR-15a/16-1 was up-regulated by all-trans retinoic acid (ATRA) treatment in NB4, HL-60 and U937 cell lines and primary leukemic cells. Overexpression of miR-15a/16-1 could not directly drive cells to undergo differentiation but enhanced ATRA-induced differentiation in NB4 and U937 cells. Up-regulation of miR-15a/16-1 was also observed in 36 patients with acute myeloid leukemia (AML) who achieved a complete remission (CR), and two of them showed sharp down-regulation of miR-15a/16-1 when they had a molecular relapse. These data indicate that miR-15a/16-1 plays an important role in the ATRA-induced differentiation of leukemic and primary AML cells.

Topics: Antineoplastic Agents; Cell Differentiation; Cell Line, Tumor; Gene Expression Regulation, Leukemic; HL-60 Cells; Humans; Leukemia; MicroRNAs; Tretinoin; U937 Cells; Up-Regulation

The membrane bound cytochrome b558 composed of large gp91-phox and small p22-phox subunits, and cytosolic proteins p40-, p47- and p67-phox are important components of superoxide (O(2)(-))-generating system in phagocytes and B lymphocytes. A lack of this system in phagocytes is known to cause serious life-threatening infections. Here, we describe that curcumin, a polyphenol responsible for the yellow color of curry spice turmeric, dramatically activates the O(2)(-)-generating system during retinoic acid (RA)-induced differentiation of human monoblastic leukemia U937 cells to macrophage-like cells. When U937 cells were cultured in the presence of RA and curcumin, the O(2)(-)-generating activity increased more than 4-fold compared with that in the absence of the latter. Semiquantitative RT-PCR showed that co-treatment with RA and curcumin slightly enhanced gene expressions of the five components compared with those of the RA-treatment only. On the other hand, immunoblot analysis revealed that co-treatment with RA and curcumin caused remarkable accumulation of protein levels of p47-phox (to 7-fold) and p67-phox (to 4-fold) compared with those of the RA-treatment alone. These results suggested that curcumin dramatically enhances RA-induced O(2)(-)-generating activity via accumulation of cytosolic p47-phox and p67-phox proteins in U937 cells. Therefore, it should have the potential as an effective modifier in therapy of leukemia and/or as an immunopotentiator.

Topics: Adjuvants, Immunologic; Antineoplastic Agents; B-Lymphocytes; Cell Line, Tumor; Curcumin; Drug Synergism; Gene Expression; Humans; Leukemia; NADPH Oxidases; Phagocytes; Phosphoproteins; Superoxides; Tretinoin

The effect of the immune regulator vitamin A on T cell death has been poorly characterized. In the present study, we demonstrate that an active metabolite of vitamin A, retinoic acid (RA), promotes cell death in Jurkat leukemic T cells by counteracting mitogen-mediated repression of Fas-induced apoptosis. The effect of RA was dose-dependent, and at the optimal concentration of 1 muM, repression of Fas-induced cell death by the mitogens 12-O-tetradecanoylphorbol 13-acetate (TPA) or Con A was reversed by approximately 50% and 30%, respectively. RA promoted apoptosis rather than necrosis, as judged by analysis of cell morphology, mitochondrial membrane depolarization, and DNA fragmentation. TPA-mediated protection from Fas-induced apoptosis is dependent on ERK and NF-kappaB. However, analyses of ERK and NF-kappaB activities and expression of target genes indicated that RA-mediated counteraction of the protective effect of TPA did not involve negative crosstalk with ERK or NF-kappaB survival pathways. RA-induced cell death was accompanied by enhanced cleavage of procaspase-3, -6, and -8, as well as enhanced cleavage of DNA fragmentation factor 45. Interestingly, RA-mediated cleavage of procaspase-8 occurred very early and before any effect of RA could be detected on procaspase-3 cleavage, suggesting that RA might act at the level of the Fas death-inducing signaling complex (DISC). Indeed, DISC immunoprecipitation studies revealed that RA treatment reversed the inhibitory effect of TPA on CH11-induced recruitment and processing of procaspase-8 at the DISC. In conclusion, we have identified a role of RA in abrogating mitogen-mediated repression of Fas DISC assembly, thus enhancing Fas-induced apoptosis in leukemic T cells.

Topics: Apoptosis; Caspase 8; Death Domain Receptor Signaling Adaptor Proteins; Extracellular Signal-Regulated MAP Kinases; fas Receptor; Humans; Jurkat Cells; Leukemia; Mitogens; NF-kappa B; Signal Transduction; T-Lymphocytes; Tretinoin

There is emerging evidence that, beyond their cholesterol-lowering properties, statins exhibit important antileukemic effects in vitro and in vivo, but the precise mechanisms by which they generate such responses remain to be determined. We have previously shown that statins promote differentiation of acute promyelocytic leukemia cells and enhance generation of all-trans retinoic acid (ATRA)-dependent antileukemic responses. We now provide evidence that statin-dependent leukemic cell differentiation requires engagement and activation of the c-Jun NH2-terminal kinase kinase pathway. In addition, in experiments, to define the molecular targets and mediators of statin-induced differentiation, we found a remarkable effect of statins on ATRA-dependent gene transcription, evidenced by the selective induction of over 400 genes by the combination of atorvastatin and ATRA. Altogether, our studies identify novel statin molecular targets linked to differentiation, establish that statins modulate ATRA-dependent transcription, and suggest that combined use of statins with retinoids may provide a novel approach to enhance antileukemic responses in acute promyelocytic leukemia and possibly other leukemias.

Topics: Antineoplastic Combined Chemotherapy Protocols; Atorvastatin; Cell Differentiation; Drug Synergism; Gene Expression Profiling; Gene Expression Regulation, Leukemic; Gene Regulatory Networks; Heptanoic Acids; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Leukemia; Oligonucleotide Array Sequence Analysis; Pyrroles; Retinoids; Time Factors; Tretinoin; Tumor Cells, Cultured

Ectopic repression of retinoic acid (RA) receptor target genes by PML/RARA and PLZF/RARA fusion proteins through aberrant recruitment of nuclear corepressor complexes drives cellular transformation and acute promyelocytic leukemia (APL) development. In the case of PML/RARA, this repression can be reversed through treatment with all-trans RA (ATRA), leading to leukemic remission. However, PLZF/RARA ectopic repression is insensitive to ATRA, resulting in persistence of the leukemic diseased state after treatment, a phenomenon that is still poorly understood. Here we show that, like PML/RARA, PLZF/RARA expression leads to recruitment of the Polycomb-repressive complex 2 (PRC2) Polycomb group (PcG) complex to RA response elements. However, unlike PML/RARA, PLZF/RARA directly interacts with the PcG protein Bmi-1 and forms a stable component of the PRC1 PcG complex, resulting in PLZF/RARA-dependent ectopic recruitment of PRC1 to RA response elements. Upon treatment with ATRA, ectopic recruitment of PRC2 by either PML/RARA or PLZF/RARA is lost, whereas PRC1 recruited by PLZF/RARA remains, resulting in persistent RA-insensitive gene repression. We further show that Bmi-1 is essential for the PLZF/RARA cellular transformation property and implicates a central role for PRC1 in PLZF/RARA-mediated myeloid leukemic development.

Topics: Antineoplastic Agents; Cell Transformation, Neoplastic; Chromatin; Humans; Leukemia; Nuclear Proteins; Oncogene Proteins, Fusion; Polycomb Repressive Complex 1; Polycomb-Group Proteins; Protein Binding; Protein Structure, Tertiary; Proto-Oncogene Proteins; Repressor Proteins; Tretinoin; U937 Cells

All-trans retinoic acid (ATRA) induces complete remission in a majority of acute promyelocytic leukaemia patients, but resistance of leukaemic cells to ATRA and its toxicity, such as hypercalcaemia, lead to a limitation of treatment. Therefore, combination therapies with differentiation-enhancing agents at non-toxic concentrations of ATRA may overcome its side effects. Here, we investigated the effect of plant-derived sesquiterpene lactone compounds and their underlying mechanisms in ATRA-induced differentiation of human leukaemia HL-60 cells.. HL-60 cells were treated with four sesquiterpene lactones (helenalin, costunolide, parthenolide and sclareolide) and cell differentiation was determined by NBT reduction, Giemsa and cytofluorometric analyses. Signalling pathways were assessed by western blotting, gel-shift assay and kinase activity determinations and intracellular calcium levels were determined using a calcium-specific fluorescent probe.. Helenalin, costunolide and parthenolide, but not sclareolide, increased ATRA-induced HL-60 cell differentiation into a granulocytic lineage. Signalling kinases PKC and ERK were involved in the ATRA-induced differentiation enhanced by all of the effective sesquiterpene lactones, but JNK and PI3-K were involved in the ATRA-induced differentiation enhanced by costunolide and parthenolide. Enhancement of cell differentiation closely correlated with inhibition of NF-kappaB DNA-binding activity by all three effective compounds. Importantly, enhancement of differentiation induced by 50 nM ATRA by the sesquiterpene lactones was not accompanied by elevation of basal intracellular calcium concentrations.. These results indicate that plant-derived sesquiterpene lactones may enhance ATRA-mediated cell differentiation through distinct pathways.

Topics: Calcium; Calcium Signaling; Cell Differentiation; HL-60 Cells; Humans; Lactones; Leukemia; Plant Extracts; Sesquiterpenes; Signal Transduction; Tretinoin

The ordered series of proliferation and differentiation from hematopoietic progenitor cells is disrupted in leukemia, resulting in arrest of differentiation at immature proliferative stages. Characterizing the molecular basis of hematopoietic differentiation is therefore important for understanding and treating disease. Retinoic acid induces expression of ankyrin repeat-containing protein with a suppressor of cytokine signaling box 2 (ASB2) in acute promyelocytic leukemia cells, and ASB2 expression inhibits growth and promotes commitment, recapitulating an early step critical for differentiation. ASB2 is the specificity subunit of an E3 ubiquitin ligase complex and is proposed to exert its effects by regulating the turnover of specific proteins; however, no ASB2 substrates had been identified. Here, we report that ASB2 targets the actin-binding proteins filamin A and B for proteasomal degradation. Knockdown of endogenous ASB2 in leukemia cells delays retinoic acid-induced differentiation and filamin degradation; conversely, ASB2 expression in leukemia cells induces filamin degradation. ASB2 expression inhibits cell spreading, and this effect is recapitulated by knocking down both filamin A and filamin B. Thus, we suggest that ASB2 may regulate hematopoietic cell differentiation by modulating cell spreading and actin remodeling through targeting of filamins for degradation.

Topics: Actins; Cell Adhesion; Cell Differentiation; Cell Line, Tumor; Contractile Proteins; Filamins; Humans; Leukemia; Microfilament Proteins; Proteasome Endopeptidase Complex; RNA, Small Interfering; Suppressor of Cytokine Signaling Proteins; Tretinoin

The development of the most common multidrug resistance (MDR) phenotype associated with a massive overexpression of P-glycoprotein (P-gp) in neoplastic cells may result in more than one hundred fold higher resistance of these cells to several drugs. L1210/VCR is a P-gp-positive drug resistant cell line in which P-gp overexpression was achieved by repeated cultivation of parental cells with a stepwise increasing concentration of vincristine. Relatively little is known about regulation of P-gp expression. Therefore, serious efforts have been made to recognize all aspects involved in regulation of P-gp expression. Retinoic acid nuclear receptors are involved in regulating expression of a large number of different proteins. Several authors have described that all-trans retinoic acid (ATRA, ligand of retinoic acid receptors, RARs) may induce alterations in P-gp expression and/or activity in drug resistant malignant cell lines. There are also other nuclear receptors for retinoids--retinoid X receptors (RXRs)--that may be involved in the development of the P-gp-mediated MDR phenotype. The topic of the present paper is a study of the relationship, if any, between the regulatory pathways of nuclear receptors for retinoids and P-glycoprotein expression. Increased levels of mRNAs encoding the retinoic acid nuclear receptors RARalpha and gamma, as well as decreased levels of the mRNAs encoding RARbeta and the retinoid X receptor RXRgamma or slightly decreased levels of RXRbeta mRNA, were observed in L1210/VCR cells in comparison with parental L1210 cells. Neither L1210 cells nor L1210/VCR cells contained measurable amounts of mRNA encoding the RXRalpha receptor. ATRA did not influence the viability of L1210/VCR cells differently from L1210 cells. A combined treatment of L1210/VCR cells with vincristine (1.08 micromol/l) and ATRA induced slightly higher cell death than that observed with ATRA alone. When applied alone, ATRA did not influence P-gp expression (monitored by anti P-gp antibody c219 using western blot analysis) or transport activity (monitored by use of calcein/AM as a P-gp substrate by FACS) in L1210/VCR cells. In contrast, when ATRA was applied together with verapamil (an often used P-gp inhibitor), a significant decrease in P-gp expression and transport activity were observed. However, no significant differences in [11, 12-(3)H]-ATRA uptake were observed in either sensitive or resistant cells, in the latter case in the absence or presence of vincristine

Topics: Animals; Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Cell Death; Cell Line, Tumor; Cell Survival; Down-Regulation; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Leukemia; Mice; Retinoid X Receptors; RNA, Messenger; Tretinoin; Verapamil; Vincristine

Changes in the promoter methylation of hTERT, the gene that encodes telomerase, a ribonucleoprotein responsible for replacing telomeric repeats, have been demonstrated in differentiating cells where hTERT is inhibited, suggesting epigenetic regulation of hTERT. All-trans retinoic acid (ATRA) induces differentiation in human leukemia cells and has had significant clinical success treating promyelocytic leukemia in what is termed 'differentiation therapy'. It is thought that the inhibition of telomerase is a target of retinoids and is closely tied to the differentiated phenotype. This study demonstrates the epigenetic changes associated with ATRA-induced inhibition of telomerase activity, including the hypoacetylation and hypermethylation of the hTERT promoter. Further, we have found changes in the differential expression of the three DNA methyltransferases during ATRA-induced differentiation of HL60 human leukemia cells. These results suggest that alteration of DNA methylation may play a role in the activation of telomerase in cancer cells and that epigenetic mechanisms may represent a target for differentiation therapy mechanisms. We propose that epigenetic changes in the hTERT promoter represent a stable locking mechanism in the retionoid-induced suppression of telomerase activity.

Topics: Apoptosis; Cell Differentiation; Cell Proliferation; Cell Survival; DNA (Cytosine-5-)-Methyltransferase 1; DNA (Cytosine-5-)-Methyltransferases; Epigenesis, Genetic; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; HL-60 Cells; Humans; Leukemia; Promoter Regions, Genetic; Protein Binding; RNA, Messenger; Telomerase; Tretinoin

DAAS is the diacetoxy acetal derivative of a-santonin and induces HL-60 cell differentiation into granulocytes. In this report, we investigated the structure-activity relationship (SAR) of DAAS derivatives in the differentiation of human HL-60 leukemia cells. Although its derivatives themselves had less effect on HL-60 cell differentiation than DAAS, the monoacetyl derivative, 2, mainly induced HL-60 cell differentiation. Moreover, compound 2 synergistically enhanced all-trans retinoic acid (ATRA)-induced HL-60 cell differentiation when combined with 50 nM ATRA, a well-known differentiation inducer. This enhancing effect is similar to that of DAAS in ATRA-induced differentiation.

Topics: Antineoplastic Agents; Cell Differentiation; Dose-Response Relationship, Drug; Drug Synergism; HL-60 Cells; Humans; Leukemia; Molecular Structure; Santonin; Structure-Activity Relationship; Tretinoin

Topics: Aged; Fatal Outcome; Filgrastim; Granulocyte Colony-Stimulating Factor; Hemorrhage; Humans; Leukemia; Male; Pulmonary Alveoli; Recombinant Proteins; Tretinoin

Human myeloid leukemia HL-60 cells are differentiated into monocytic or granulocytic lineage when treated with 1,25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)] or all-trans retinoic acid (RA), respectively. In this study, the effect of acetone fraction prepared from bamboo leaf on cell differentiation was investigated in a HL-60 cell culture system. Treatment of HL-60 cells with 50-400 microg/ml acetone fraction of bamboo leaf for 72 hr inhibited cell proliferation and induced a little increase in cell differentiation, as demonstrated by the MTT and nitroblue tetrazolium reduction assay. Interestingly, synergistic induction of HL-60 cell differentiation was observed when the acetone fraction of bamboo leaf was combined with either 5 nM 1,25-(OH)(2)D(3) or 50 nM all-trans RA. Flow cytometric analysis indicated that combinations of 1,25-(OH)(2)D(3) and the acetone fraction of bamboo leaf stimulated differentiation predominantly to monocytes, whereas combinations of all-trans RA and the acetone fraction of bamboo leaf stimulated differentiation predominantly to granulocytes. These results suggest that the acetone fraction of bamboo leaf enhanced leukemia cell differentiation and suggest a possibility of bamboo in the treatment of leukemia.

Topics: Antineoplastic Agents; Calcitriol; Cell Differentiation; Dose-Response Relationship, Drug; HL-60 Cells; Humans; Leukemia; Plant Extracts; Plant Leaves; Poaceae; Tretinoin; Vitamins

Differentiation of various leukemic cells can be induced by liganded retinoic acid receptors and protein phosphatase inhibitors. In this study, we explored the effects of okadaic acid (OA), the phosphatase inhibitor, and retinoic acid (RA) in v-myb-transformed monoblasts BM2. OA induced differentiation of BM2 monoblasts into macrophage-like cells, as documented by analyses of cell morphology, cell cycle, phagocytic activity, non-specific esterase activity, production of reactive oxygen species and expression of vimentin and Mo-1. In contrast to many other leukemic cell lines, BM2 cells do not respond to retinoic acid. However, once exposed to OA and RA simultaneously, BM2 cells differentiate along monocyte/macrophage pathway more efficiently. We conclude that RA enhances differentiation of v-myb-transformed monoblasts induced by protein phosphorylation.

Topics: Animals; Antineoplastic Agents; Cell Differentiation; Cell Line, Transformed; Cell Line, Tumor; Chickens; Genes, myb; Immunoblotting; Leukemia; Macrophages; Monocytes; Okadaic Acid; Transcriptional Activation; Transfection; Tretinoin

To investigate effects of arsenic trioxide (As(2)O(3)) and alltrans retinoic acid (ATRA) on PLZF-RARalpha-positive cells.. PLZF-RARalpha-positive U937 cells (U937/PLZF) were used as an in vitro model. The change of cell morphology was observed by Wright-Giemsa staining. Cell growth and proliferation were detected by methyl thiazolyl tetrazolium(MTT) assay. Cell cycle distribution and expression of cell membrane surface differentiation-related antigens (such as CD11b, CD64 and CD14) were determined by flow cytometry assay. Expression of PLZF was analyzed by immunofluorescence. Functional differentiation was reflected by nitroblue tetrazolium(NBT) reduction ability and cytochemistry staining.. While U937/PLZF cells were incubated in tetracycline-withdrawn medium, the expression of PLZF-RARalpha; protein increased. After treated with As(2)O(3) (0.5 micromol/L) and ATRA (1 mumol/L), U937/PLZF cells presented some changes such as decreased nuclear/cytoplasm ratio, and partial disappearance of nucleoli, suggesting a certain degree of morphological differentiation. The cell growth and proliferation were inhibited in a dose- and time-dependent manner. The proportion of cells in S phage was decreased and CD11b level was increased. The expression of PLZF relocated in treated cells. However, no significant difference in NBT assay and cytochemistry staining was documented with the combination therapy.. The combination of As(2)O(3) with ATRA can cause a slight tendency to morphological differentiation but is insufficient to induce functional differentiation of PLZF-RARalpha positive U937 leukemia cells.

Topics: Antigens, CD; Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Cell Cycle; Cell Proliferation; Flow Cytometry; Gene Expression Regulation, Neoplastic; Humans; Kruppel-Like Transcription Factors; Leukemia; Nitroblue Tetrazolium; Oxidation-Reduction; Oxides; Promyelocytic Leukemia Zinc Finger Protein; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Tetracycline; Tretinoin; U937 Cells

When a human leukemic cell line, HT93 was incubated with all-trans retinoic acid (ATRA), IL-5, or both, this cell line was differentiated into eosinophic lineage, in that an eosinophilic specific granule proteins, major basic protein (MBP) and eosinophil peroxidase (EPO) appeared. Both CD11b and CC chemokine receptor, CCR3 expression were upregulated, while CD71 expression was downregulated by ATRA or ATRA+IL-5. Concomitantly, marked production of eotaxin-2/CCL24 was observed, but no production of eotaxin-1/CCL11 and eotaxin-3/CCL26 was detected. Since only 20 to 30% cells incubated with ATRA became positive for CCR3, CCR3(+) population was enriched by a magnetic activated cell sorter (MACS). Enriched CCR3(+) population produced higher eotaxin-2/CCL24 than the CCR3(-) population, indicating that differentiated eosinophils are capable of producing eotaxin-2/CCL24. During the ATRA-induced differentiation, expression of a transcriptional factor, GATA-1 was significantly increased. Introduction of siRNA against GATA-1 markedly reduced the ATRA-induced differentiation markers including CD11b and CCR3, as well as reduced eotaxin-2/CCL24 production. Finally, ATRA-induced differentiation and eotaxin-2/CCL24 production were greatly enhanced in the GATA-1-overexpressed clones. These results indicate that the ability to produce eotaxin-2/CCL24 is acquired during the differentiation into eosinophilic lineage which is dependent on GATA-1 expression.

Topics: Blotting, Western; Cell Differentiation; Cell Line, Tumor; Cell Lineage; Chemokine CCL24; Chemokines, CC; DNA Primers; Down-Regulation; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; GATA1 Transcription Factor; GATA2 Transcription Factor; Gene Expression Regulation, Neoplastic; Humans; Interleukin-5; Leukemia; Receptors, CCR3; Receptors, Chemokine; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; Tretinoin

To investigate pig7 expression level in acute leukemia (AL) and its clinical significance and explore the possible mechanisms for pig7 silence in terms of methylation control.. Expression levels of pig7 mRNA in bone marrow samples from 138 patients with de novo AL and 21 normal controls and in 6 leukemic cell lines were detected by quantitative real-time reverse transcription PCR (RT-PCR). Differentiation induction effect by all-trans retinoic acid (ATRA) and concomitant change in pig7 expression were also monitored in NB4 cells. Endonuclease analysis was employed to determined the identity of pig7 transcript present in AL samples. Methylation specific PCR (MSP) was used to elucidate if hypermethylation was responsible for pig7 silence in AL.. Compared with that in normal control, pig7 expression was markedly decreased (0.62 vs 18.30, median, P < 0.01) in AL patients on progression (at diagnosis, relapse or refractory). No significant difference was observed between acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). AL at diagnosis had a higher pig7 level than those with relapsed or refractory disease (1.43 vs 0.16, median, P < 0.05). The complete remission (CR) rate after chemotherapy was found to be significantly correlated with pig7 expression levels (P < 0.05). Differentiated NB4 cells showed an increased level of pig7 expression (from 1.61 +/- 0.72 to 44.75 +/- 3.93, P < 0.01). Only one form of pig7 transcripts i.e., Small integral membrane protein of late endosome (SIMPLE), was detected in AL patients. Hypermethylation of pig7 promoter was identified in K562 and HL-60 cells, in contrast to non-methylation predominant in U937 cells.. Aberrant down-regulation of pig7 provides novel insights into leukemogenesis and therapy response prediction in AL.

Topics: Acute Disease; Cell Differentiation; Cell Line, Tumor; DNA Methylation; Gene Expression Regulation, Leukemic; Humans; Leukemia; Nuclear Proteins; Promoter Regions, Genetic; RNA, Messenger; Transcription Factors; Tretinoin

To study the reactivation of retinoic acid receptor beta (RARbeta) expression in myeloid leukemia cells by a combination of all-trans retinoic acid (ATRA) with a DNA demethylating agent, decitabine (DAC), and valproic acid (VPA, a histone deacetylase inhibitor),and their effects on cell differentiation and proliferation.. Human myeloid leukemia cells of the line U937 were cultured and treated with all-trans retinoic acid (ATRA), DAC, and VPA. 72 h later cell differentiation test, cloning formation test, and chromatin immunoprecipitation test were performed. Bone marrow specimens were collected from 56 patients with acute myeloblastic leukemia (AML) were cultured and treated with and 10 bone marrow specimens were used as controls. Methylation of RARbeta promoter was detected with methylation specific polymerase chain reaction (MSP) after bisulfite treatment. Relative levels of RARbeta mRNA were assessed with real time quantitative PCR assay. Flow cytometry assay was used to detect the myeloid differentiation marker CD11b in U937 cells. Chromatin immuno-precipitation assay (ChIP) was used to analyze the acetylated histone 3 bound to the retinoic acid response element (RARE) at the promoter region of RARbeta.. Methylation of RARbeta was positive in 36 of the 56 (64.3%) AML patients and the U937 myeloid leukemia cells, however, was negative in the marrow mononuclear cells from the 10 healthy donors. The expression of RARbeta in U937 cells was up-regulated after treatment with ATRA (1 micromol/L) plus DAC (1 micromol/L) or VPA (0.5 mmol/L) for 72 hours, especially when the three drugs were used together. ChIP assay showed that the acetylated histone 3 bound to the RARE promoter region was increased after the cells were exposed to ATRA plus DAC/VPA. The data indicated that the reactivated expression of RARbeta might be secondary to the drug-induced histone acetylation as well as DNA demethylation. Treatment of U937 cells with ATRA and DAC/VPA also resulted in increased myeloid differentiation (CD11b expression) and decreased plating efficiency.. The repressed expression of RARbeta in myeloid leukemia cells is closely related to both DNA hypermethylation and histone deacetylation, and a combination of ATRA with epigenetic modulators can be beneficial in the treatment of myeloid malignancies.

Topics: Acetylation; Adult; Aged; Azacitidine; Chromatin Immunoprecipitation; CpG Islands; Decitabine; DNA Methylation; Epigenesis, Genetic; Gene Expression Regulation, Leukemic; Histones; Humans; Leukemia; Middle Aged; Receptors, Retinoic Acid; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tretinoin; U937 Cells; Valproic Acid

Microarrays used for gene expression studies yield large amounts of data. The processing of such data typically leads to lists of differentially-regulated genes. A common terminal data analysis step is to map pathways of potentially interrelated genes.. We applied a transcriptomics analysis tool to elucidate the underlying pathways of leukocyte maturation at the genomic level in an established cellular model of leukemia by examining time-course data in two subclones of U-937 cells. Leukemias such as Acute Promyelocytic Leukemia (APL) are characterized by a block in the hematopoietic stem cell maturation program at a point when expansion of clones which should be destined to mature into terminally-differentiated effector cells get locked into endless proliferation with few cells reaching maturation. Treatment with retinoic acid, depending on the precise genomic abnormality, often releases the responsible promyelocytes from this blockade but clinically can yield adverse sequellae in terms of potentially lethal side effects, referred to as retinoic acid syndrome.. Briefly, the list of genes for temporal patterns of expression was pasted into the ABCC GRID Promoter TFSite Comparison Page website tool and the outputs for each pattern were examined for possible coordinated regulation by shared regelems (regulatory elements). We found it informative to use this novel web tool for identifying, on a genomic scale, genes regulated by drug treatment.. Improvement is needed in understanding the nature of the mutations responsible for controlling the maturation process and how these genes regulate downstream effects if there is to be better targeting of chemical interventions. Expanded implementation of the techniques and results reported here may better direct future efforts to improve treatment for diseases not restricted to APL.

Topics: Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Cluster Analysis; Data Interpretation, Statistical; Databases, Factual; Down-Regulation; Gene Expression Regulation, Neoplastic; Genes, Regulator; Granulocyte Precursor Cells; Humans; Internet; Leukemia; Oligonucleotide Array Sequence Analysis; Proteins; RNA, Messenger; Time Factors; Transcription Factors; Transcription, Genetic; Tretinoin; U937 Cells; Up-Regulation

All-trans retinoic acid (ATRA) induces differentiation of NB4 and HL-60 leukemia cells, but not R4 and HL-60/Res cells. Three agents used in cancer therapy, doxorubicin (Dox), arsenic trioxide (As(2)O(3)) and paclitaxel, induce apoptosis, but not differentiation, in all of these cell lines. The induction of apoptosis by these agents is decreased in ATRA-pretreated NB4 and HL-60 cells, but not in ATRA-pretreated R4 and HL-60/Res cells. The level of Bcl-2 protein is decreased by ATRA treatment in NB4, HL-60 and HL-60/Res cells. The level of Mcl-1 protein is increased by ATRA treatment in NB4 and R4 cells, but not in HL-60 and HL-60/Res cells. Bfl-1/A1 mRNA is not expressed in these cell lines, however, its expression is markedly induced by ATRA treatment in NB4 and HL-60 cells, but not in R4 or HL-60/Res cells, which correlates with inhibition of apoptosis. Inhibiting Bfl-1/A1 mRNA upregulation in ATRA-pretreated NB4 cells using small interfering RNA (siRNA) partly recovers cell sensitivity to Dox-induced apoptosis. These data demonstrate that ATRA induction of Bfl-1/A1 in differentiated NB4 and HL-60 cells contributes to a loss of sensitivity to chemotherapy-induced apoptosis.

Topics: Antineoplastic Agents; Apoptosis; Arsenic Trioxide; Arsenicals; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Doxorubicin; Gene Silencing; HL-60 Cells; Humans; Leukemia; Minor Histocompatibility Antigens; Oxides; Paclitaxel; Proto-Oncogene Proteins c-bcl-2; RNA, Small Interfering; Tretinoin; Up-Regulation

Hematological malignancies such as leukemia or lymphoma are mainly treated by hospitalization or in outpatient clinics. Therefore, home care and home nursing are not so intensively done in the treatment of these malignancies. However, G-CSF administration against neutropenia after chemotherapy and administration of narcotics or opioids against severe pain have been performed sometimes during home care, and have been contributing to better QOL of the patients.

Topics: Analgesics, Opioid; Granulocyte Colony-Stimulating Factor; Home Care Services, Hospital-Based; Humans; Leukemia; Lymphoma; Multiple Myeloma; Myelodysplastic Syndromes; Neutropenia; Pain; Quality of Life; Tretinoin

Topics: Adolescent; Anthracyclines; Antimetabolites, Antineoplastic; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Cytarabine; Female; Humans; Leukemia; Leukemia, Promyelocytic, Acute; Oxides; Risk; Skin; Tretinoin

Acute promyelocytic leukemia (APL) cells express promyelocytic leukemia/retinoic acid receptor alpha (PML/RARalpha) fusion protein, which leads to the blocking of APL cell differentiation. Treatment of APL with all-trans-retinoic acid (ATRA) induces disease remission by in vivo differentiation of APL cells. Differentiation requires cell cycle exit; yet how ATRA couples cell cycle exit to differentiation of APL remains largely unknown. We previously found that ATRA-induced cell differentiation accompanies ubiquitination-proteolysis of ménage à trois 1 (MAT1), an assembly factor and targeting subunit of cyclin-dependent kinase (CDK)-activating kinase (CAK) that regulates G1 exit. We report here that CAK binds to and phosphorylates PML/RARalpha in actively proliferating APL cells. In response to ATRA, PML/RARalpha is dissociated from CAK, leading to MAT1 degradation, G1 arrest, and decreased CAK phosphorylation of PML/RARalpha. CAK phosphorylation of PML/RARalpha is inhibited when MAT1 levels are reduced. Both MAT1 degradation and PML/RARalpha hypophosphorylation occur in ATRA-induced G1-arresting cells undergoing differentiation but not in the synchronized G1 cells that do not differentiate. These findings reveal a novel ATRA signaling on APL cell differentiation, in which ATRA coordinates G1 arrest and transition into differentiation by inducing MAT1 degradation and PML/RARalpha hypophosphorylation through disrupting PML/RARalpha binding and phosphorylation by CAK.

Topics: Carrier Proteins; Cell Cycle Proteins; Cell Differentiation; Cell Line, Tumor; Cyclin-Dependent Kinase-Activating Kinase; Cyclin-Dependent Kinases; G1 Phase; Humans; Leukemia; Oncogene Proteins, Fusion; Peptide Hydrolases; Phosphorylation; Protein Binding; Transcription Factors; Tretinoin; Ubiquitin

Histone deacetylase inhibitors have a potent role in the strategy for the treatment of leukemias. BML-210 (N-(2-Aminophenyl)-N' phenyloctanol diamine) is the novel histone deacetylase inhibitor, and its mechanism of action has not been characterized. In this study, we examined the in vitro effects of BML-210 on the human leukemia cell lines (NB4, HL-60, THP-1, and K562). We found that BML-210 inhibits the growth of all cell lines and promotes apoptosis in a dose- and time-dependent manner. BML-210 alone induces HL-60 and K562 cell differentiation (up to 30%) to granulocytes and erythrocytes, respectively, and in combination with differentiation agents - all-trans retinoic acid and hemin, markedly potentates it. Those treatments cause G1 arrest and histone H4 acetylation, affects transcription factor NF-kappaB and Sp1 binding activity to their consensus sequences, the p21 or the FasL promoters, and influences expression of Sp1, NF-kappaB, p21 and FasL. These findings suggest that BML-210 could be a promising antileukemic agent to induce apoptosis and to modulate differentiation through the modulation of histone acetylation and gene expression.

Topics: Acetylation; Anilides; Apoptosis; Blotting, Western; Cell Cycle; Cell Differentiation; Cell Line; Cell Line, Tumor; Cell Nucleus; Cell Proliferation; Cytoplasm; Dose-Response Relationship, Drug; Electrophoretic Mobility Shift Assay; Histone Deacetylase Inhibitors; Histone Deacetylases; Histones; HL-60 Cells; Humans; K562 Cells; Leukemia; NF-kappa B; Protein Binding; Time Factors; Transcription Factors; Tretinoin; Tumor Suppressor Protein p53

Topics: Humans; Internal Medicine; Internship and Residency; Israel; Leukemia; Leukemia, Promyelocytic, Acute; Tretinoin

PMA (10, 20 ng/ml) and doxorubicin (5-20 ng/ml) decreased the viability and MTT-activity of NALM-1 pre-B leukemic cells (3 days' treatment). Further, CD10 was downregulated, suggesting that PMA and doxorubicin induced differentiation of NALM-1 cells. However, PMA did not alter expression of B cell markers CD20 and of mIgM. In contrast to PMA, another differentiation agent ATRA did not alter CD10 expression on NALM-1 cells but affected viability after 6 days (5, 10 ng/ml). The data in this study are the first evidence that PMA and doxorubicin inhibited viability and MTT activity and induced partial differentiation, by decreasing CD10 on NALM-1 cells.

Topics: Antibiotics, Antineoplastic; Antigens, CD20; Biomarkers, Tumor; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; Doxorubicin; Enzyme-Linked Immunosorbent Assay; Formazans; Humans; Immunoglobulin mu-Chains; Leukemia; Neprilysin; Syndecan-1; Tetradecanoylphorbol Acetate; Tetrazolium Salts; Time Factors; Tretinoin

To study the fibrinolytic activity and the expression of uPAR and Annexin II in leukemic cell lines and their alterations on all-trans retinoic acid ( ATRA) treatment.. The fibrinolytic activity was measured by chromogenic assay in NB4, SHI-1, K562, Jurkat and Raji cell lines. The protein expression of uPAR and Annexin II on cells surface and the mRNA expression of uPAR and Annexin II in cells of these cell lines were detected using flow cytometry and RT-PCR method respectively.. The plasmin activity in supernatant was increased significantly after incubation of SHI-1 and NB4 cells with plasminogen. The plasmin activity of NB4 cells was obviously decreased by ATRA. The plasmin activity of NB4 and SHI-1 cells was significantly decreased by uPAR monoclonal antibodies. The expressions of uPAR and Annexin II and their mRNA in SHI-1 and NB4 cells were higher than that in other cell lines. ATRA could remarkably decrease the expressions of Annexin II and uPAR and their mRNA in NB4 cells.. In leukemia cell lines, NB4 and SHI-1 cells have stronger fibrinolytic activity. Both Annexin II and uPAR on the leukemic cell membranes might contribute to this activity. The high fibrinolytic activity can be corrected by ATRA by down-regulating Annexin I and uPAR mRNA and protein expression in NB4 cells.

Topics: Annexin A2; Cell Line, Tumor; Fibrinolysis; Humans; Leukemia; Receptors, Cell Surface; Receptors, Urokinase Plasminogen Activator; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tretinoin

FK228 (depsipeptide) is a novel histone deacetylase inhibitor (HDACI) that has shown therapeutical efficacy in clinical trials for malignant lymphoma. In this article, we examined in vitro effects of FK228 on human leukemia cell lines, NB4 and HL-60. FK228 alone (0.2-1 ng/mL) inhibited leukemia cell growth in a dose-dependent manner and induced death by apoptosis. FK228 had selective differentiating effects on two cell lines when used for 6 h before induction of granulocytic differentiation by retinoic acid (RA) or in combination with RA. These effects were accompanied by a time- and dose-dependent histone H4 hyper-acetylation or histone H3 dephosphorylation and alterations in DNA binding of NF-kappaB in association with cell death and differentiation. Pifithrin-alpha (PFT), an inhibitor of p53 transcriptional activity, protected only NB4 cells with functional p53 from FK228-induced apoptosis and did not interfere with antiproliferative activity in p53-negative HL-60 cells. In NB4 cells, PFT inhibited p53 binding to the p21 (Waf1/Cip1) promotor and induced DNA binding of NF-kappaB leading to enhanced cell survival. Thus, beneficial effects of FK228 on human promyelocytic leukemia may be exerted through the induction of differentiation or apoptosis via histone modification and selective involvement of transcription factors, such as NF-kappaB and p53.

Topics: Antibiotics, Antineoplastic; Apoptosis; Cell Differentiation; Cell Line, Tumor; Depsipeptides; Growth Inhibitors; Histone Deacetylase Inhibitors; HL-60 Cells; Humans; Leukemia; Tretinoin

5-Hydroxy- and 4-amino-2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione (5HPP-33 and 4APP-33, respectively) have been shown to possess cell differentiation-inducing activity toward human leukemia cell line HL-60.

Topics: Antineoplastic Agents; Cell Differentiation; Drug Screening Assays, Antitumor; Flow Cytometry; HL-60 Cells; Humans; Indoles; Isoindoles; Leukemia; Lipopolysaccharide Receptors; Structure-Activity Relationship; Thalidomide

The Eight twenty-one (ETO) homologues are nuclear repressor proteins including ETO, myeloid-transforming gene-related protein 1 (MTGR1), and myeloid-transforming gene chromosome 16 (MTG16). ETO and MTG16 are both part of fusion proteins resulting from chromosomal translocations associated with acute myeloid leukemia. Expression of these chimeras results in a differentiation block that contributes to the onset of leukemia. In order to elucidate the relation between the ETO homologues and hematopoietic differentiation, we determined the expression of the homologues during differentiation of leukemic and normal hematopoietic cells. Our results showed MTGR1 and MTG16 to be ubiquitously expressed in leukemic cell lines, whereas expression of ETO was observed only in an erythroleukemic cell line. The MTGR1 and MTG16 proteins decreased during all trans-retinoic acid-, but not vitamin D(3)-induced differentiation of leukemic cells. The reduction seemed to reflect a decrease in transcript levels as well as in protein stability. MTGR1 transcripts were ubiquitously expressed in human bone marrow cells. The MTG16 transcripts of CD34(+) progenitor cells were rapidly downregulated by cytokine-induced differentiation into myeloid or erythroid lineages. ETO transcripts, present at very low abundance in CD34(+) progenitor cells, were transiently upregulated during erythroid differentiation. In conclusion, the differential expression of the ETO homologues suggests that they may have a potential role in hematopoietic differentiation.

Topics: Bone Marrow Cells; Cell Differentiation; Cell Line; Cell Line, Tumor; DNA Primers; DNA-Binding Proteins; Flow Cytometry; Gene Expression Regulation, Neoplastic; Hematopoietic Stem Cells; HL-60 Cells; Humans; K562 Cells; Kidney; Leukemia; Phosphoproteins; Polymerase Chain Reaction; Proto-Oncogene Proteins; Repressor Proteins; Reverse Transcriptase Polymerase Chain Reaction; Tetradecanoylphorbol Acetate; Transcription Factors; Tretinoin; Tumor Suppressor Proteins; U937 Cells

As a single signal, retinoids induce terminal differentiation. This implies that they activate differentiation and apoptosis in a temporally defined order to allow expression of the differentiated phenotype well before death. We report that two apparently contradictory retinoid-induced programs have the capacity to define cellular life span. Anti-apoptotic factors are activated concomitantly with differentiation, while retinoids induce at the same time also pro-apoptotic signaling. We have assessed the roles of two key factors, Bcl2A1 and TRAIL, in the temporal programming of cell death and differentiation. We demonstrate that PLB985 are type II cells in which TRAIL induces apoptosis through the extrinsic and--via Bid activation--also the intrinsic death pathways. Bcl2A1, ectopically over-expressed, or endogenously induced by retinoic acid receptor agonists, protected cells from apoptosis triggered by TRAIL, whose induction required the activation of both the retinoic acid and retinoid X receptors. Bcl2A1 prevented loss of mitochondrial membrane potential and caspase-9, but not caspase-8, activation. The expression of anti-sense Bcl2A1 sensitized PLB985 cells to TRAIL. Co-culture experiments revealed protection from fraternicide if sister cells were pre-exposed to retinoic acid. Collectively, our data support a model in which retinoids orchestrate a life span-regulatory program comprising Bcl2A1 induction to temporally protect against concomitantly induced TRAIL death signaling. Termination of this life span in presence of Bcl2A1 is most likely a consequence of the Bid-independent TRAIL action. Thus, depending on the retinoic acid and retinoid X receptor activation potential of a ligand and the relative efficacies of the intrinsic and extrinsic death pathways in a given cell, a single retinoid triggers the life span of a differentiated phenotype.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Base Sequence; Blotting, Western; Cellular Senescence; Coculture Techniques; DNA Primers; Flow Cytometry; Humans; Leukemia; Membrane Glycoproteins; Minor Histocompatibility Antigens; Proto-Oncogene Proteins c-bcl-2; Reverse Transcriptase Polymerase Chain Reaction; TNF-Related Apoptosis-Inducing Ligand; Tretinoin; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

A major obstacle in the successful delivery of antibody-based therapeutics to tumor cells is the heterogeneity of target antigen expression. We reported previously that retinoic acid (RA) is a potent and selective inducer of the cell-surface antigen CD38 in myeloid leukemia cells. The purpose of this study was to determine whether the RA-induced CD38 antigen could be a target for an anti-CD38-based immunotoxin to induce selective killing of leukemia cells. The combination of RA and the anti-CD38 gelonin immunotoxin induced a synergistic killing of leukemia cells. Thus, coculture of myeloid leukemia cells and cell lines with as little as 1 nM RA in the presence of immunotoxin induced substantial killing (>90%) of leukemia cell clones. More importantly, the blasts of myeloid leukemia patients, irrespective of their morphological and phenotypic features, also responded to the RA and immunotoxin combination when cultured ex vivo. A similar synergistic effect between RA and immunotoxin was observed against a multidrug-resistant variant subline of HL-60 cells. However, another variant of HL-60 cells, HL-60R, in which the retinoid receptor function has been abrogated by a trans-dominant-negative mutation, exhibited complete resistance to the immunotoxin-induced killing effect in the presence or absence of RA. Our results suggest that RA combined with anti-CD38-based therapeutic agent may offer exciting opportunities for the treatment of myeloid leukemias despite their multiplicity of genetic and clinical varieties.

Topics: ADP-ribosyl Cyclase; ADP-ribosyl Cyclase 1; Antibodies, Monoclonal; Antigens, CD; Antineoplastic Agents; Cell Line, Tumor; DNA, Complementary; Dose-Response Relationship, Drug; Drug Resistance, Multiple; HL-60 Cells; Humans; Immunotherapy; Immunotoxins; Leukemia; Membrane Glycoproteins; Mutation; Plant Proteins; Ribosome Inactivating Proteins, Type 1; Tretinoin

In this study, hematopoietic cells from human placental blood were treated with the differentiation-inducing drug all-trans retinoic acid (ATRA). Their cytoplasm was then used to culture the human myelogenous leukemia cell line HL60, NB(4) cells and the RA-resistant HL60-R and NB(4)-R(2) cells. All of these four kinds of leukemia cells underwent macrophage/monocyte differentiation and apoptosis, while their proliferation was inhibited. This suggests that the RA receptors were not essentially needed in this situation, and this method should be applicable in the treatment of RA-resistant promyelocytic leukemia as well as other kinds of leukemia.

Topics: Apoptosis; Cell Differentiation; Culture Media; Cytoplasm; Drug Resistance, Neoplasm; Hematopoietic Stem Cells; Humans; Leukemia; Leukocytes, Mononuclear; Placenta; Tretinoin; Tumor Cells, Cultured

Treatment of acute leukaemia in adult Jehovah's Witnesses (JW) is challenging because of 'a priori' refusal of most physicians to apply diagnostic and therapeutic procedures to haematological abnormalities resembling acute leukaemia. Rejection of blood transfusions by individuals of this faith is usually blamed to justify this attitude, thus leading to severe personal, medical and psychological distress related to the lack of care. We therefore intended to verify whether a standard (tailored) chemotherapy, without the use of prophylactic blood product transfusions, could be applied during treatment of acute leukaemia under such circumstances. Eleven consecutive JW adult patients with acute leukaemia, all of whom had been denied care in other institutions, were treated at the European Institute of Oncology (EIO) in Milan, Italy. Five had acute lymphoblastic leukaemia (ALL) (one bcr/abl positive), six had acute myeloid leukaemia (AML) with immunophenotype and/or cytogenetic intermediate-high risk features, except one patient with acute promyelocytic leukaemia (APML). Standard induction chemotherapy [cytosine arabinoside (ARA-C) and daunorubicin (DNR) for AML, vincristine (VCR), DNR and prednisone (PDN) for ALL, all-trans retinoic acid (ATRA) and DNR for APML] with the antracycline dose of at least 30 mg/sqm were used. All patients experienced severe anaemia after induction chemotherapy despite erythropoietin. Median haemoglobin nadir for patients with ALL and AML was 4.5 g/dL (range 1.3-6.9) and 5.1 g/dL (range 2.6-6.8), respectively. Median platelet nadir counts for all patients was 14.5 x 10(9))/L (range 1-24). One patient died during induction probably due to haemorrhage. Four of five patients with ALL achieved a complete remission (CR) (including the bcr/abl case) while among patients with AML only the one with APML achieved CR. Three patients (APML = 1 and ALL = 2) are still alive and disease-free. This small series of adult patients with leukaemia illustrates difficulties in treating patients who are practising JW, yet nevertheless provides a significant argument against the prejudicial decision leading to evasion of treatment in these patients.

Topics: Acute Disease; Adult; Antineoplastic Combined Chemotherapy Protocols; Case Management; Cytarabine; Daunorubicin; Etoposide; Female; Hemoglobins; Hemorrhage; Humans; Jehovah's Witnesses; Leukemia; Male; Middle Aged; Multiple Organ Failure; Patient Acceptance of Health Care; Refusal to Treat; Remission Induction; Tretinoin; Vincristine

We have previously shown that forced expression of the transcription factor Scl in WEHI-3B D(+) cells prevents ATRA-induced cell differentiation. We now find that the overexpression of Rbtn2 also interferes with induction of differentiation by ATRA. Addition of LiCl to ATRA treatment restored the capacity of both Scl- and Rbtn2-expressing cells to respond to the retinoid in a synergistic manner. Similar results were obtained with Scl-transfected HL60 cells where its expression diminished responsiveness to ATRA. These findings suggest that if Scl and/or Rbtn2 are involved in the non-responsiveness of AML patients to ATRA-induced differentiation, addition of LiCl may reverse insensitivity.

Topics: Adaptor Proteins, Signal Transducing; Adjuvants, Immunologic; Animals; Antineoplastic Agents; Basic Helix-Loop-Helix Transcription Factors; Blotting, Western; Cell Differentiation; DNA-Binding Proteins; Drug Synergism; HL-60 Cells; Humans; Leukemia; LIM Domain Proteins; Lithium Chloride; Metalloproteins; Proto-Oncogene Proteins; T-Cell Acute Lymphocytic Leukemia Protein 1; Transcription Factors; Transfection; Tretinoin

To investigate the expression of VEGF mRNA and secretion of VEGF protein in NB4 and HL-60 cells affected by all-trans retinoic acid (ATRA) and daunorubincin (DNR) respectively.. Semi-quantitative RT-PCR and ELISA were used to study the expression of VEGF mRNA and secretion of VEGF protein in NB4 and HL-60 cell lines treated by ATRA and DNR respectively.. VEGF was expressed in both NB4 and HL-60 cells. The expression of VEGF mRNA and secretion of VEGF protein could be down-regulated by ATRA and DNR respectively in a time and dose dependent manner.. Besides inducing apoptosis and restraining proliferation of leukemic cells, ATRA and DNR exerted their anti-leukemia effects by reducing angiogenesis via reduction of angiogenic reaction stimulating signals.

Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Daunorubicin; Gene Expression Regulation, Leukemic; HL-60 Cells; Humans; Leukemia; Tretinoin; Vascular Endothelial Growth Factors

Cyclooxygenase (COX)-1 or -2 and specific prostaglandin (PG) synthases catalyze the formation of various PGs. We investigated the expression and activity of COX-1 and -2 during granulocyte-oriented maturation induced by all-trans-retinoic acid (ATRA) of NB4 cells, originated from a human acute promyelocytic leukemia (APL), and in blasts from APL patients. The expression of COX isoenzymes or prostaglandin synthases was also investigated in circulating granulocytes and human bone marrow. COX-1 was expressed and enzymatically active in NB4 cells and primary blasts. COX-1 mRNA and protein were induced by ATRA. COX-1 protein increased approximately 2-3.5-fold by culture day 3 in NB4 cells and primary blasts, while basal COX-2 expression was very low and unaffected by ATRA. COX-1-dependent PGE(2) biosynthesis increased during differentiation approx. 5-fold. Indomethacin and the selective COX-1 inhibitor SC-560, but not selective COX-2 inhibition, impaired NB4 differentiation, reducing NADPH-oxidase activity, CD11b and CD11c expression. The immunohistochemistry of granulocytes and myeloid precursors in the bone marrow showed a large prevalence of COX-1 as compared to COX-2. In conclusion, COX-1 is induced during ATRA-dependent maturation and appears to contribute to myeloid differentiation both in vitro and ex vivo, and COX-1 activity may potentiate the differentiation of human APL.Leukemia (2004) 18, 1373-1379. doi:10.1038/sj.leu.2403407 Published online 10 June 2004

Topics: Blood Cells; Bone Marrow Cells; Cell Differentiation; Cell Line, Tumor; Cyclooxygenase 1; Cyclooxygenase 2; Dinoprostone; Granulocytes; Humans; Isoenzymes; Leukemia; Leukemia, Promyelocytic, Acute; Membrane Proteins; Myelopoiesis; Prostaglandin-Endoperoxide Synthases; RNA, Messenger; Tretinoin; Tumor Cells, Cultured; Up-Regulation

Retinoids and interferons are signaling molecules with pronounced anticancer activity. We show that in both acute promyelocytic leukemia and breast cancer cells the retinoic acid (RA) and interferon signaling pathways converge on the promoter of the tumoricidal death ligand TRAIL. Promoter mapping, chromatin immunoprecipitation and RNA interference reveal that retinoid-induced interferon regulatory factor-1 (IRF-1), a tumor suppressor, is critically required for TRAIL induction by both RA and IFNgamma. Exposure of breast cancer cells to both antitumor agents results in enhanced TRAIL promoter occupancy by IRF-1 and coactivator recruitment, leading to strong histone acetylation and synergistic induction of TRAIL expression. In coculture experiments, pre-exposure of breast cancer cells to RA and IFNgamma induced a dramatic TRAIL-dependent apoptosis in heterologous cancer cells in a paracrine mode of action, while normal cells were not affected. Our results identify a novel TRAIL-mediated tumor suppressor activity of IRF-1 and suggest a mechanistic basis for the synergistic antitumor activities of certain retinoids and interferons. These data argue for combination therapies that activate the TRAIL pathway to eradicate tumor cells.

Topics: Antineoplastic Agents; Apoptosis Regulatory Proteins; Breast Neoplasms; Cell Line, Tumor; Cell Survival; DNA-Binding Proteins; Humans; Interferon Regulatory Factor-1; Interferon-gamma; Leukemia; Membrane Glycoproteins; Phosphoproteins; Promoter Regions, Genetic; Signal Transduction; TNF-Related Apoptosis-Inducing Ligand; Tretinoin; Tumor Necrosis Factor-alpha

Dysregulation of epigenetic control is an important participant in carcinogenesis. The PML/RAR alpha translocation in acute promyelocytic leukemia (APL) is an example where the resultant fusion protein recruits histone deacetylase complexes to target genes resulting in their inappropriate transcriptional repression. All-trans-retinoic acid (ATRA) acts as a ligand that relieves this repression and produces an epigenetic transcriptional reprogramming of the cancer cell. CpG island microarrays were used to analyze the DNA methylation and histone acetylation state of the human APL cell line NB4 before and after differentiation with ATRA as well as normal peripheral blood mononuclear cells (PBMC). Over 70 CpG islands within 1 kb of transcription start of a known gene are aberrantly methylated in NB4 cells compared with PBMC; however, no changes in cytosine methylation were detected following ATRA-induced differentiation. With respect to histone H4 acetylation, over 100 single-copy CpG islands within 1 kb of transcription start of a known human gene became hyperacetylated following ATRA-induced differentiation. One CpG island was aberrantly methylated in NB4 cells, but became hyperacetylated and was induced following ATRA treatment and was associated with the HoxA1 gene, suggesting it may be a target gene of ATRA in APL. In addition to single-copy sequences, a selective increase in acetylation was detected in satellite DNA when compared with other high-copy sequences, such as Alu or rDNA. In summary, ATRA stimulates complex epigenomic changes during leukemic cell differentiation, and monitoring these changes may help to identify new targets of epigenetic dysfunction.

Topics: Acetylation; Cell Differentiation; Chromatin; CpG Islands; Cytosine; Databases, Genetic; DNA; Gene Library; Histones; Humans; Immunoprecipitation; In Situ Hybridization; Keratolytic Agents; Leukemia; Methylation; Oligonucleotide Array Sequence Analysis; Reverse Transcriptase Polymerase Chain Reaction; Sulfites; Tretinoin

Although phospholipid scramblase 1 (PLSCR1) was originally identified based on its capacity to promote transbilayer movement of membrane phospholipids, subsequent studies also provided evidence for its role in cell proliferation, maturation, and apoptosis. In this report, we investigate the potential role of PLSCR1 in leukemic cell differentiation. We show that all-trans retinoic acid (ATRA), an effective differentiation-inducing agent of acute promyelocytic leukemic (APL) cells, can elevate PLSCR1 expression in ATRA-sensitive APL cells NB4 and HL60, but not in maturation-resistant NB4-LR1 cells. ATRA- and phorbol 12-myristate 13-acetate (PMA)-induced monocytic differentiation is accompanied by increased PLSCR1 expression, whereas only a slight or no elevation of PLSCR1 expression is observed in U937 cells differentiated with dimethyl sulfoxide (DMSO), sodium butyrate, or vitamin D3. Cell differentiation with ATRA and PMA, but not with vitamin D3 or DMSO, results in phosphorylation of protein kinase Cdelta (PKCdelta), and the PKCdelta-specific inhibitor rottlerin nearly eliminates the ATRA- and PMA-induced expression of PLSCR1, while ectopic expression of a constitutively active form of PKCdelta directly increases PLSCR1 expression. Finally, decreasing PLSCR1 expression with small interfering RNA inhibits ATRA/PMA-induced differentiation. Taken together, these results suggest that as a protein induced upon PKCdelta activation, PLSCR1 is required for ATRA- and PMA-triggered leukemic cell differentiation.

Topics: Cell Differentiation; Cell Line, Tumor; Humans; Leukemia; Membrane Proteins; Phospholipid Transfer Proteins; Phosphorylation; Protein Kinase C; Protein Kinase C-delta; RNA, Small Interfering; Tetradecanoylphorbol Acetate; Tretinoin; Up-Regulation

The nuclear receptor ligand all-trans retinoic acid (ATRA) causes dramatic terminal differentiation of acute promyelocytic leukemia (APL) cells in vitro and in patients, but it is less active in other malignancies. However, downstream mediators of the effects of ATRA are not well understood. We used a cDNA microarray to search for ATRA-regulated genes in the APL cell line NB4 and found that ATRA regulated several members of the tumor necrosis factor (TNF) pathway. Here we show that TNF can synergize with ATRA to induce differentiation, showing monocytic characteristics more typical of differentiation mediated by TNF than by ATRA. ATRA and TNF can also induce differentiation of the non-APL cell line U937. Underlying this response was an increase in TNF-induced nuclear factor-kappaB (NF-kappaB) DNA binding within 2 hours in the presence of ATRA and activation of NF-kappaB DNA binding and transcriptional activity in response to ATRA alone within 48 hours of ATRA treatment. Furthermore, we found a synergistic induction of the NF-kappaB target genes BCL-3, Dif-2, and TNF receptor 2 (TNFR2) in response to the combination of TNF and ATRA. These genes have been previously shown to play a role in TNF signaling, and amplification of such genes may represent a mechanism whereby TNF and ATRA can act synergistically. We propose that ATRA can prime cancer cells for differentiation triggered by TNF and suggest that targeting the TNF pathway in combination with ATRA may represent a novel route to treat leukemias.

Topics: Acute Disease; Apoptosis; Cell Differentiation; DNA; Drug Synergism; Gene Expression Regulation, Leukemic; Humans; Leukemia; NF-kappa B; Transcription, Genetic; Tretinoin; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

Differentiation in the hematopoietic system involves, among other changes, altered expression of antigens, including the CD34 and CD38 surface antigens. In normal hematopoiesis, the most immature stem cells have the CD34 + CD34 - phenotype. In acute myeloid leukemia (AML), although blasts from most patients are CD38 +, some are CD38 - . AML blasts are blocked at early stages of differentiation; in some leukemic cells this block can be overcome by a variety of agents, including retinoids, that induce maturation into macrophages and granulocytes both in vitro and in vivo. Retinoids can also induce CD38 expression. In the present study, we investigated the relationship between induction of CD38 expression and induction of myeloid differentiation by retinoic acid (RA) in normal and leukemic human hematopoietic cells. In the promyelocytic (PML) CD34 - cell lines, HL60 and CB-1, as well as in normal CD34 + CD34 - hematopietic progenitor cells RA induced both CD38 expression as well as morphological and functional myeloid differentiation that resulted in loss of self-renewal. In contrast, in the myeloblastic CD34 + leukemic cell lines, ML-1 and KG-1a, as well as in primary cultures of cells derived from CD34 + -AML (M0 and M1) patients, RA caused an increase in CD38 + that was not associated with significant differentiation. Yet, long exposure of ML-1, but not KG-1, cells to RA resulted in loss of self-renewal. The results suggest that while in normal hematopoietic cells and in PML CD34 - cells induction of CD38 antigen expression by RA results in terminal differentiation along the myeloid lineage, in early myeloblastic leukemic CD34 + cells, induction of CD38 and differentiation are not functionally related. Since, several lines of evidence suggest that the CD38 - cells are the targets of leukemic transformation, transition of these cellsinto CD38 + phenotype by RA or other drugs may have therapeutic effect, either alone or in conjunction with cytotoxic drugs, regardless the ability of the cells to undergo differentiation.

Topics: ADP-ribosyl Cyclase; ADP-ribosyl Cyclase 1; Antigens, CD; Antigens, CD34; Antineoplastic Agents; Cell Differentiation; Cell Division; Cell Line; Cell Line, Tumor; Dose-Response Relationship, Drug; HL-60 Cells; Humans; Immunophenotyping; Leukemia; Leukemia, Myeloid, Acute; Membrane Glycoproteins; Myeloid Cells; Phenotype; Time Factors; Tretinoin

Topics: Acute Disease; Blood Coagulation; Hemorrhage; Humans; Leukemia; Tretinoin

To explore whether the oligonucleotide uptake in hematological tumor cells is related to cellular species and proliferation.. Intracellular mean fluorescence intensity was measured by flow cytometry.. After treatment with FITC-labeled G3139 at the concentration of 0.60 mumol.L-1 for 4 h, the G3139 uptake into peripheral blood mononuclear cell and bone marrow mononuclear cell in hematological tumor patients was significantly higher than that in normal control. There was different uptake of G3139 among the malignant hematological tumor cell strains, and the uptake in cells derived from monocyte, B lymphocyte and myeloid cell was much higher than that in cells derived from T lymphocyte. After treatment with all-trans retinoic acid (ATRA), HL60 cell proliferation was markedly inhibited and the uptake of G3139 decreased significantly.. Hematological tumor cells were capable of taking up oligonucleotide, and the oligonucleotide uptake in hematological tumor cells is related to its cellular species and its activation.

Topics: Biological Transport; Cell Division; Genes, bcl-2; HL-60 Cells; Humans; Leukemia; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Promyelocytic, Acute; Leukocytes, Mononuclear; Lymphoma, Non-Hodgkin; Oligonucleotides, Antisense; Thionucleotides; Tretinoin; Tumor Cells, Cultured

We have previously described a microarray of cluster of differentiation (CD) antibodies that enables concurrent determination of more than 60 CD antigens on leukocytes. This procedure does not require protein purification or labeling, or a secondary detection system. Whole cells are captured by a microarray of 10 nL antibody dots immobilized on a nitrocellulose film on a microscope slide. Distinct patterns of cell binding are observed for different leukemias or lymphomas. These haematological malignancies arise from precursor cells of T- or B-lymphocytic, or myeloid lineages of hematopoiesis. The dot patterns obtained from patients are distinct from those of peripheral blood leukocytes from normal subjects. This microarray technology has recently undergone a number of refinements. The microarray now contains more CD antibodies, and a scanner for imaging dot patterns and software for data analysis provide an extensive immunophenotype sufficient for diagnosis of common leukemias. The technology is being evaluated for diagnosis of leukemias with parallel use of conventional diagnostic criteria.

Topics: Antibodies; Antigens, Surface; Collodion; HL-60 Cells; Humans; Leukemia; Leukocytes; Lymphoma; Tretinoin

Retinoic acid (RA) has important effects on cell differentiation and cell growth and on normal embryonic development. Intracellular retinoid signaling induced by endogenous or exogenous RA is regulated by retinoid binding proteins such as CRBPI, CRABPI and CRABPII and there are data suggesting that the expression of these proteins can influence the sensitivity to the growth inhibitory effects of ATRA. In this study, we investigated the basal and ATRA-induced expression of CRBPI and CRABPI and II in leukemic cell lines and in cells from patients with acute myeloid leukemia (AML). CRBPI as well as CRABPI and II were expressed in all tested cell lines and in leukemic cells from all 18 AML-patients. CRABPII mRNA expression was more abundant than CRBPI and CRABPI in both the cell lines and the patient cells but the levels compared the house keeping gene was lower in the patient cells. In all cell lines and in 69% of the patient samples, ATRA did upregulate CRABPII whereas CRBPI exhibited a varying response and CRABPI was more commonly downregulated. The sensitivity to the growth inhibitory effects of ATRA did not correlate with the basal expression of any of these proteins. However, ATRA-induced upregulation of CRABPII did significantly correlate with the ATRA sensitivity (p < 0.005) as well as with ATRA-induced upregulation of the retinoid receptor RARbeta (p < 0.05). We conclude that the retinoid binding proteins CRBPI and CRABPI and II are expressed in myeloid leukemic cells of non-M3 type but that the level of expression does not affect ATRA sensitivity.

Topics: Gene Expression; Humans; Leukemia; Receptors, Retinoic Acid; Retinol-Binding Proteins; Retinol-Binding Proteins, Cellular; RNA, Messenger; Tretinoin; Tumor Cells, Cultured; Up-Regulation

FK228 [(E)-(1S,4S,10S,21R)-7-[(Z)-ethylidene]-4,21-diisopropyl-2-oxa-12,13-dithia-5,8,20,23-tetraazabicyclo-[8,7,6]-tricos-16-ene-3,6,9,19,22-pentanone; FR901228, depsipeptide] is a novel histone deacetylase inhibitor that shows therapeutic efficacy in Phase I trials of patients with malignant lymphoma. However, its mechanism of action has not been characterized. In this study, we examined the in vitro and in vivo effects of FK228 on human lymphoma U-937 cells. FK228 very strongly inhibited the growth of U-937 cells with an IC(50) value of 5.92 nM. In a scid mouse lymphoma model, mice treated with FK228 once or twice a week survived longer than control mice, with median survival times of 30.5 (0.56 mg/kg) and 33 days (0.32 mg/kg), respectively (vs. 20 days in control mice). Remarkably, 2 out of 12 mice treated with FK228 (0.56 mg/kg once or twice a week) survived past the observation period of 60 days. The apoptotic population of U-937 cells time-dependently increased to 37.7% after 48 hr of treatment with FK228. In addition, FK228 induced G1 and G2/M arrest and the differentiation of U-937 cells to the CD11b(+)/CD14(+) phenotype. Expression of p21(WAF1/Cip1) and gelsolin mRNA increased up to 654- and 152-fold, respectively, after 24hr of treatment with FK228. FK228 caused histone acetylation in p21(WAF1/Cip1) promoter regions, including the Sp1-binding sites. In conclusion, (i) FK228 prolonged the survival time of scid mice in a lymphoma model, and (ii) the beneficial effects of FK228 on human lymphoma may be exerted through the induction of apoptosis, cell cycle arrest, and differentiation via the modulation of gene expression by histone acetylation.

Topics: Acetylation; Animals; Anti-Bacterial Agents; Antibiotics, Antineoplastic; Apoptosis; Cell Cycle; Cell Differentiation; Cholecalciferol; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Depsipeptides; Disease Models, Animal; Gelsolin; Histone Deacetylase Inhibitors; Histones; Humans; Leukemia; Lymphoma; Mice; Mice, SCID; Neoplasm Transplantation; Peptides, Cyclic; Promoter Regions, Genetic; RNA, Messenger; Tretinoin; U937 Cells; Xenograft Model Antitumor Assays

Leukotriene C(4) synthase (LTC(4) S) is considered a pivotal enzyme for generation of potent proinflammatory mediators, cysteinyl-leukotrienes (cysLTs). LTC(4) S cDNA was cloned in rat basophilic leukemia-1 (RBL-1) cells, and exhibited 84.8% and 94.5% identity with the reported human and mouse LTC(4) S cDNA sequences, respectively. Homology between the rat LTC(4) S amino acid sequence and the corresponding sequences from the other species was 86.5% and 95.3% with human and mouse sequences, respectively. Rat LTC(4) S thus showed extensive homology with both mouse and human cDNA sequences. The active enzyme as assessed by LTC(4) S activity was expressed in COS-7 cells. While RBL-1 cells after the culture for 48 h in the presence of 0.1 microg/ml all trans -retinoic acid (RA) exhibited 27 times higher LTC(4) S activity than control cells, Northern-blot analysis of RA-treated cells showed upregulation of LTC(4) S mRNA. Polyclonal antibody was raised against the synthesized peptide deduced from the nucleotide sequence. Thus, Western-blot analysis of RBL-1 cells treated with RA and COS-7 cells transfected with pcDNA-LTC(4) S commonly showed a band at approximately 18 kDa in each solubilized enzyme solution, but either control cells did not. This cDNA probe and antibody may be useful for investigating the roles of cysLTs in various experimental models of rats.

Topics: Amino Acid Sequence; Animals; Base Sequence; Blotting, Western; Cell Line, Tumor; Cloning, Molecular; DNA, Complementary; Gene Expression Regulation, Neoplastic; Glutathione Transferase; Humans; Leukemia; Mice; Molecular Sequence Data; Rats; RNA, Messenger; Sequence Homology, Amino Acid; Solubility; Tretinoin

In myeloid leukemia, immature leukemic cells are able to egress into peripheral blood to infiltrate extra-medullary organs. We therefore analyzed the migrating and invasive potential of human HL-60 and NB4 cell lines, representative of acute myelogenous leukemia, their ability to express matrix metalloproteases (MMPs), tissue inhibitors of metalloproteases (TIMPs) and urokinase plasminogen activator (uPA) in response to differentiating agents. Granulocytic differentiation by all-trans-retinoic acid (ATRA) and aclacinomycin (ACLA) strongly increased HL-60 and NB4 cell migration and invasion. At mRNA and protein levels, these cell lines produced significant amounts of MMP-9 (HL-60

Topics: Aclarubicin; Antineoplastic Agents; Cell Differentiation; Cell Movement; HL-60 Cells; Humans; Leukemia; Matrix Metalloproteinase 9; Neoplasm Invasiveness; Phenylalanine; Serine Endopeptidases; Thiophenes; Tissue Inhibitor of Metalloproteinases; Tretinoin; Tumor Cells, Cultured

The cellular prion protein (PrPc) is a sialoglycoprotein involved in the pathogenesis of prion diseases. It has been identified at the plasma membrane of several cell types. All-trans retinoic acid (ATRA) is known to induce differentiation of human leukemia cell lines in vitro. PrPc messenger ribonucleic acid (mRNA) and protein are down-regulated upon ATRA-induced differentiation of HL60 cells. In this report, we have investigated the regulation of PrPc mRNA and protein expression during ATRA-treatment of maturation-sensitive (NB4) and -resistant (NB4-R1 and NB4-R2) cell lines. In ATRA-induced maturation of NB4 cells, down-regulation of PrPc mRNA and protein were observed. We also show that down-regulation of PrPc mRNA is dependent on protein synthesis. Moreover, the same down-regulation of prion protein by ATRA was observed at the surface of maturation-resistant, ATRA-responsive NB4-R1 cells. In contrast, the maturation-resistant and ATRA-unresponsive NB4-R2 subline showed no variation in membrane prion protein expression. These results demonstrate a dissociation between the regulation of prion protein expression by ATRA and the process of granulocyte maturation. We propose that retinoids should be investigated further as a preventive strategy to slow down prion disease progression.

Topics: Cell Differentiation; Dose-Response Relationship, Drug; Down-Regulation; Granulocytes; Humans; Kinetics; Leukemia; Membrane Proteins; PrPC Proteins; RNA, Messenger; Tretinoin; Tumor Cells, Cultured

To investigate PML gene and protein expression and localization in leukemia cell lines.. Cell morphology was assayed by Wright and fluorescence stain, PML mRNA expression by RT-PCR, and PML protein localization by immunofluorescence.. (1) Differentiation was observed by morphology in NB4 and HL-60 cells after treatment with all-trans retinoic acid (ATRA) while K562 cells did not show. Apoptosis was found in each cell line after treatment with quercetin. (2) After treatment with ATRA, the fusion protein disappeared and PML protein resumed in NB4 cells, while in HL-60 and K562 cells there was no difference from control cells. After treatment with quercetin, the fusion protein disappeared in NB4 cells, then degraded, and so did in HL-60 cells and K562 cells. (3) The expression of PML mRNA had no change in all the three cell lines after treatment with ATRA or quercetin.. PML plays a role of differentiation and apoptosis induction in leukemia cells at the translational level. PML in POD plays a role of apoptosis induction and growth control of leukemia cells.

Topics: Cell Division; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; HL-60 Cells; Humans; K562 Cells; Leukemia; Neoplasm Proteins; Nuclear Proteins; Promyelocytic Leukemia Protein; Quercetin; RNA, Messenger; Time Factors; Transcription Factors; Tretinoin; Tumor Cells, Cultured; Tumor Suppressor Proteins

Topics: Antineoplastic Agents; Cell Differentiation; Enzyme Inhibitors; Histone Deacetylase 1; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Leukemia; Transcription Factors; Tretinoin; Tumor Cells, Cultured

Most chromosomal abnormalities associated with breakage at 11q23 in acute leukaemia involve the MLL gene, and the presence of this breakage strongly predicts a poor clinical outcome. We assessed the possibility of differentiation-inducing therapy for acute leukaemias with chromosomal translocations involving 11q23. Among the cell lines with MLL translocations that we examined, KOCL48 and KOPN-1 cells were induced to differentiate into granulocytes by all-trans retinoic acid (ATRA) or into monocytes by 1alpha,25-dihydroxyvitamin D3 (VD3). These cells expressed p16 mRNA before treatment with 5-aza-2'-deoxycytidine (5-AZA), an inhibitor of DNA methylation. On the other hand, differentiation was not induced in SN-1, KOCL33, KOCL51 or KOCL44 cells by ATRA or VD3, and these cells did not express mRNA of this gene. However, these cells were effectively induced to differentiate by ATRA or VD3 in the presence of 5-AZA, and concomitantly exhibited p16 gene expression, suggesting an association between DNA demethylation and restoration of sensitivity to differentiation-inducing activity of ATRA or VD3 in leukaemia cells with MLL abnormalities. Based on these findings, combined treatment with ATRA or VD3 plus 5-AZA may be clinically useful in therapy for acute leukaemia with MLL abnormalities.

Topics: Antimetabolites, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Azacitidine; Calcitriol; Cell Differentiation; Chromosome Breakage; Chromosomes, Human, Pair 11; Decitabine; DNA Methylation; DNA-Binding Proteins; Histone-Lysine N-Methyltransferase; Humans; Leukemia; Myeloid-Lymphoid Leukemia Protein; Proto-Oncogenes; Transcription Factors; Tretinoin; Tumor Cells, Cultured

C-type natriuretic peptide (CNP) is the third member of the natriuretic peptide family. Cultured endothelial cells secrete CNP, and its secretion rate from the endothelial cells is augmented by lipopolysaccharide, interleukin-1beta, and tumor necrosis factor-alpha, which participate in the pathophysiology of inflammation. In this study, we investigated the regulation of CNP secretion from monocytes and macrophages to estimate its contribution to the progression of inflammation.. CNP secretion rates from two human leukemia cell lines (THP-1 and HL-60), human peripheral blood lymphocytes, granulocytes, monocytes, monocyte-derived macrophages, and mouse peritoneal macrophages were measured under conditions with or without stimulation. Immunoreactive CNP levels in the culture media of these cells were measured by a specific radioimmunoassay.. The secretion rates of CNP from THP-1 and HL-60 cells were augmented according to the degree of their differentiation into macrophage-like cells under the stimulation with phorbol ester. Peripheral blood monocytes also increased the CNP secretion rate after their differentiation into macrophages. Retinoic acid elicited synergistic effects on the CNP secretion rate from HL-60 cells when administered with lipopolysaccharide, interferon-gamma, interleukin-1beta, tumor necrosis factor-alpha, or phorbol ester. In contrast, the phorbol ester-stimulated CNP secretion rate from THP-1 cells was suppressed with dexamethasone, which inhibits monocyte differentiation into macrophage.. The secretion rate of CNP from monocytes was shown to be regulated based on the degree of their differentiation. This study provides evidence that the monocyte/macrophage system is one of the sources of CNP, especially under inflammatory conditions.

Topics: Animals; Blood Cells; Cell Differentiation; Dexamethasone; HL-60 Cells; Humans; Interferon-gamma; Interleukin-1; Leukemia; Lipopolysaccharides; Macrophages, Peritoneal; Mice; Mice, Inbred C3H; Monocytes; Natriuretic Peptide, C-Type; Neoplasm Proteins; Tetradecanoylphorbol Acetate; Transforming Growth Factor beta; Tretinoin; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

Influx of Ca(2+) represents an important regulatory signal in the process of cell proliferation. However, little is known about how Ca(2+) entry changes during the cell-cycle. Patch-clamp experiments and microfluorimetry show that store-operated Ca(2+) entry was substantially reduced in rat basophilic leukaemia cells cultured for 24h under serum-free conditions. Likewise, retinoic acid treatment blocked Ca(2+) influx activated by store depletion via inositol 1,4,5-trisphosphate. Both procedures are known to arrest cells at the G0/G1 boundary of the cell-cycle and induced a reduction in 5-bromo 2'-deoxyuridine incorporation into DNA. Ca(2+) release from the stores remained unaltered and two types of K(+) currents were not affected in cells after serum starvation. The specific reduction in Ca(2+) entry was not detected when using aphidicolin, 5-fluorouracil or thymidine to synchronise the cell-cycle. These data suggest that store-operated Ca(2+) influx changed during cell-cycle progression which might have important implications for cell growth.

Topics: Animals; Antimetabolites, Antineoplastic; Antineoplastic Agents; Aphidicolin; Bromodeoxyuridine; Calcium; Cell Cycle; Cell Division; Culture Media, Serum-Free; Enzyme Inhibitors; Fluorouracil; Guanosine 5'-O-(3-Thiotriphosphate); Inositol 1,4,5-Trisphosphate; Leukemia; Patch-Clamp Techniques; Potassium; Potassium Channels; Rats; Time Factors; Tretinoin; Tumor Cells, Cultured

Increasing resistance to chemotherapeutic regimes remains a serious problem in the treatment of acute myeloid leukaemia. We have shown that phosphatidylinositol (PI) 3-kinase inhibition significantly sensitises the AML derived cell line, HL60 to chemotherapeutic drug- and Fas-induced apoptosis. PI3-kinase inhibition significantly potentiates cytotoxic drug-induced c-jun N-terminal kinase (JNK) activation, reported to be a requirement for apoptosis. However, JNK inhibition does not enhance cell viability following treatment with drug and inhibitor. Furthermore, PI3-kinase inhibition significantly increases sensitivity to apoptosis mediated by an exogenous receptor agonist, again by a JNK independent mechanism. These results suggest that PI3-kinase inhibitors could be of significant therapeutic importance, lowering the threshold for apoptosis induced by both chemotherapy and cell-mediated immune response.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Agents; Apoptosis; Enzyme Activation; Fas Ligand Protein; fas Receptor; HL-60 Cells; Humans; JNK Mitogen-Activated Protein Kinases; Leukemia; Membrane Glycoproteins; Mitogen-Activated Protein Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Transcription, Genetic; Tretinoin

Lithium affects several enzymatic activities, however, the molecular mechanisms of lithium actions are not fully understood. We previously showed that LiCl interacts synergistically with all-trans-retinoic acid to promote terminal differentiation of WEHI-3B D(+) cells, a phenomenon accompanied by the recovery of the retinoid-induced loss of retinoic acid receptor alpha protein pools. Here, we demonstrate the effects of LiCl on proteasome-dependent degradation of retinoic acid receptor alpha proteins. LiCl alone, or in combination with all-trans-retinoic acid, increased cellular levels of ubiquitinated retinoic acid receptor alpha and markedly reduced chymotryptic-like activity of WEHI-3B D(+) 20 S and 26 S proteasome enzymes. Neither KCl nor all-trans-retinoic acid affected enzyme activity, whereas NaCl produced a modest reduction at relatively high concentrations. In addition, LiCl inhibited 20 S proteasome chymotryptic-like activity from rabbits but had no effect on tryptic-like activity of the 26 S proteasome. This effect has significant consequences in stabilizing the retinoic acid receptor alpha protein levels that are necessary to promote continued differentiation of leukemia cells in response to all-trans-retinoic acid. In support of this concept, combination of proteasome inhibitors beta-clastolactacystin or benzyloxycarbonyl-Leu-Leu-Phe with all-trans-retinoic acid increased differentiation of WEHI-3B D(+) cells in a manner that was analogous to the combination of LiCl and all-trans-retinoic acid.

Topics: Adjuvants, Immunologic; Animals; Blotting, Western; Cell Differentiation; Cell Line; Chymotrypsin; Cysteine Endopeptidases; Humans; Kinetics; Lactones; Leukemia; Lithium Chloride; Multienzyme Complexes; Oligopeptides; Peptide Hydrolases; Precipitin Tests; Proteasome Endopeptidase Complex; Protein Binding; Protein Biosynthesis; Rabbits; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Time Factors; Tretinoin; Trypsin; Tumor Cells, Cultured; Ubiquitin

To better understand the role of retinoids in myelopoiesis, expression of the retinoid receptor genes (retinoic acid receptors [RARs] and retinoid X receptors [RXRs]) were examined during differentiation of factor-dependent cell-Paterson (FDCP)-mixA4 murine progenitor cells. The major receptor expressed in undifferentiated A4 cells was RARalpha (primarily the RARalpha1 isoform). Following induction of myelomonocytic differentiation with granulocyte and granulocyte-macrophage colony-stimulating factors, a dramatic increase in RARalpha expression (particularly the RARalpha2 isoform) was seen. In contrast, expression of both RARalpha isoforms was rapidly extinguished upon induction of erythroid differentiation with erythropoeitin (EPO). A modest induction of RXRalpha expression was seen, particularly during differentiation in the myelomonocytic lineage. Low expression levels of RARgamma2 and RXRbeta remained unchanged, irrespective of differentiation pathway. Consistent with the gene expression patterns, RARalpha agonists and antagonists stimulated myelomonocytic and erythroid differentiation of FDCP-mixA4 cells, respectively. Taken together, these results suggest that erythropoiesis and granulopoiesis require diminished and enhanced RARalpha activities, respectively, which at physiological all-trans-retinoic acid (RA) concentrations may be accomplished by reciprocal effects of EPO and myelomonocytic growth factors on its expression. This hypothesis is corroborated by data showing that RA, which positively regulates RARalpha2 expression, can exert inhibitory effects on erythroid differentiation.

Topics: Bone Marrow; Bone Marrow Cells; Cell Differentiation; Cells, Cultured; DNA Primers; Erythropoietin; Gene Expression Regulation; Granulocyte Colony-Stimulating Factor; Granulocyte-Macrophage Colony-Stimulating Factor; Hematopoietic Stem Cells; HL-60 Cells; Humans; Leukemia; Models, Biological; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Reverse Transcriptase Polymerase Chain Reaction; Tretinoin; Tumor Cells, Cultured

Carnosic acid, the polyphenolic diterpene derived from rosemary, is a strong dietary antioxidant that exhibits antimutagenic properties in bacteria and anticarcinogenic activity in various cell and animal models. In the present study, we show that carnosic acid (2.5-10 microM) inhibits proliferation of HL-60 and U937 human myeloid leukemia cells (half-maximal inhibitory concentration = 6-7 microM) without induction of apoptotic or necrotic cell death. Growth arrest occurred concomitantly with a transient cell cycle block in the G1 phase, which was accompanied by an increase in the immunodetectable levels of the universal cyclin-dependent kinase inhibitors p21WAFI and p27Kipl. Carnosic acid caused only a marginal induction of differentiation, as monitored by the capacity to generate superoxide radicals and the expression of cell surface antigens (CD11b and CD14) and receptors for the chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine. However, at low concentrations, this polyphenol substantially augmented (100- to 1,000-fold) the differentiating effects of 1,25-dihydroxyvitamin D3 and all-trans retinoic acid. Furthermore, such combinations of carnosic acid and any of these differentiation inducers synergistically inhibited proliferation and cell cycle progression. These results indicate that carnosic acid is capable of antiproliferative action in leukemic cells and can cooperate with other natural anticancer compounds in growth-inhibitory and differentiating effects.

Topics: Abietanes; Antineoplastic Agents, Phytogenic; Apoptosis; Calcitriol; Cell Cycle; Cell Cycle Proteins; Cell Differentiation; Cell Division; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Cyclins; Diterpenes; Drug Interactions; Flow Cytometry; G1 Phase; HL-60 Cells; Humans; Leukemia; Leukemia, Myeloid; Plant Extracts; Rosmarinus; Tretinoin; Tumor Cells, Cultured; Tumor Suppressor Proteins; U937 Cells

Retinoids are known to induce the differentiation and cell cycle arrest of human myeloid leukemia cells in vitro. Differential display was used to identify putative early regulatory genes that are differentially expressed in HL-60 human promyelocytic leukemia cells treated with retinoic acid. One of the cDNAs cloned encodes sequences identifying Burkitt's lymphoma receptor 1 (BLR1), a recently described chemokine receptor. Northern blot analysis demonstrates that blr1 mRNA expression increases within 9 h of retinoic acid treatment, well before functional differentiation or G(1)/G(0) growth arrest at 48 h or onset of morphological changes, suggesting a possible regulatory function. The expression of blr1 mRNA is transient, peaking at 72 h when cells are differentiated. blr1 mRNA also is induced by other differentiation-inducing agents, 1alpha,25-dihydroxyvitamin D(3) and DMSO. Induction of blr1 mRNA by retinoic acid is not blocked by the protein synthesis inhibitor cycloheximide. In HL-60 cells stably transfected with blr1 cDNA, ectopic expression of blr1 causes an increase in ERK2 MAPK activation and promotes retinoic acid-induced G(1)/G(0) growth arrest and cell differentiation. The early expression of blr1 mRNA during differentiation, its ability to increase ERK2 activation, and its enhancement of retinoic acid-induced differentiation suggest that blr1 expression may be involved in retinoic acid-induced HL-60 differentiation.

Topics: Alternative Splicing; Calcitriol; Cell Differentiation; Cell Division; Cycloheximide; Dimethyl Sulfoxide; G1 Phase; Gene Expression Regulation; HL-60 Cells; Humans; Kinetics; Leukemia; Membrane Glycoproteins; Mitogen-Activated Protein Kinase 1; Receptors, Chemokine; Receptors, CXCR5; Receptors, Cytokine; Recombinant Proteins; Resting Phase, Cell Cycle; Transcription, Genetic; Transfection; Tretinoin; Tumor Cells, Cultured

The resistance to all trans retinoic acid (ATRA) differentiating treatment is a consequence, in most of the cases, of either increased catabolism or down regulation of ATRA uptake. Recently, we have shown that ATRA efficiency to differentiate HL-60 cells was enhanced about 30 times after its incorporation into Low Density Lipoprotein (ATRA-LDL). Here, we attempted to differentiate the ATRA-resistant HL-60 cells by ATRA-LDL at high concentrations up to 10 microM. No significant differentiating effect was observed, although the LDL receptor sites were evidenced in these cells. To increase the number of LDL receptors, the cells were pre-incubated in lipoprotein-deprived serum medium and compactin (2 microM), both ATRA and ATRA-LDL induced gradual increase of cell differentiation (35%+/-1 and 51.5%+/-5 at 10 microM of ATRA and ATRA-LDL respectively). At 2 and 8 microM, the intracellular concentrations of ATRA were respectively three and four times higher when incorporated into LDL. In addition, ATRA-LDL, in the medium, was better protected against degradation than ATRA. The surprising restoration of free ATRA sensitivity after treatment with compactin suggested the implication of new mechanisms unrelated to the LDL-receptor endocytosis but involving the non-sterol pathway.

Topics: Antineoplastic Agents; Binding, Competitive; Chromatography, High Pressure Liquid; Drug Interactions; Drug Screening Assays, Antitumor; HL-60 Cells; Humans; Leukemia; Lovastatin; Receptors, LDL; Tretinoin; Tumor Cells, Cultured

Expression of the cyclin-dependent kinase inhibitor p15(INK4B) frequently is altered in myeloid malignancies. We previously demonstrated that p15(INK4B) is expressed in normal myeloid cells. The aim of this study was to investigate whether p15(INK4B) expression is restricted to the granulomonocytic lineage and to evaluate its modulation during normal and leukemic myeloid differentiation.. Normal CD34(+) cells were cultured in serum-free media to obtain granulomonocytic, erythroid, or megakaryocytic unilineage differentiation. NB4 promyelocytic cell line and fresh leukemic blasts from seven patients with acute promyelocytic leukemia were cultured with all-trans retinoic acid. At different times of culture, cell samples were collected to evaluate p15(INK4B) by semiquantitative reverse transcriptase polymerase chain reaction.. p15(INK4B) mRNA was found during granulomonocytic and megakaryocytic, but not erythroid, differentiation. In the granulomonocytic lineage, p15(INK4B) was detectable when the majority of cells were at the promyelocytic stage and increased progressively in more mature elements. In the megakaryocytic lineage, p15(INK4B) was expressed in the early phase of differentiation, before megakaryoblasts had appeared, and was mantained throughout the time of culture. NB4 cell line and five of seven leukemic samples displayed undetectable or very low level of p15(INK4B) that rapidly increased during retinoic acid-induced differentiation. Two leukemic samples (both collected from two patients developing all-trans retinoic acid syndrome) showed high basal levels of p15(INK4B), which was not modified by retinoic acid treatment.. p15(INK4B) upregulation occurs specifically during normal granulomonocytic and megakaryocytic commitment. In acute promyelocytic leukemic blasts, p15(INK4B), which is detectable at a very low level, is promptly increased by retinoic acid. In contrast, two acute promyelocytic leukemia samples obtained from patients who developed all-trans retinoic acid syndrome showed high basal levels of p15(INK4B) that did not increase further during all-trans retinoic acid-induced differentiation.

Topics: Antigens, CD34; Bone Marrow Cells; Carrier Proteins; Cell Cycle Proteins; Cell Differentiation; Cells, Cultured; Cyclin-Dependent Kinase Inhibitor p15; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinases; Gene Expression Regulation; Hematopoietic Stem Cells; Humans; Kinetics; Leukemia; RNA, Messenger; Transcription, Genetic; Tretinoin; Tumor Suppressor Proteins

RAR and AML1 transcription factors are found in leukemias as fusion proteins with PML and ETO, respectively. Association of PML-RAR and AML1-ETO with the nuclear corepressor (N-CoR)/histone deacetylase (HDAC) complex is required to block hematopoietic differentiation. We show that PML-RAR and AML1-ETO exist in vivo within high molecular weight (HMW) nuclear complexes, reflecting their oligomeric state. Oligomerization requires PML or ETO coiled-coil regions and is responsible for abnormal recruitment of N-CoR, transcriptional repression, and impaired differentiation of primary hematopoietic precursors. Fusion of RAR to a heterologous oligomerization domain recapitulated the properties of PML-RAR, indicating that oligomerization per se is sufficient to achieve transforming potential. These results show that oligomerization of a transcription factor, imposing an altered interaction with transcriptional coregulators, represents a novel mechanism of oncogenic activation.

Topics: Cell Transformation, Neoplastic; Core Binding Factor Alpha 2 Subunit; Histone Deacetylases; Humans; Leukemia; Leukemia, Myeloid; Leukemia, Promyelocytic, Acute; Neoplasm Proteins; Nuclear Proteins; Nuclear Receptor Co-Repressor 1; Oncogene Proteins, Fusion; Peptide Fragments; Protein Binding; Protein Structure, Quaternary; Repressor Proteins; Response Elements; RUNX1 Translocation Partner 1 Protein; Transcription Factors; Transcription, Genetic; Tretinoin

Acute promyelocytic leukemia (APL) is associated with a hemorrhagic disorder of unknown cause that responds to treatment with all-trans-retinoic acid.. We studied a newly described receptor for fibrinolytic proteins, annexin II, in cells from patients with APL or other leukemias. We examined initial rates of in vitro generation of plasmin by tissue plasminogen activator (t-PA) in the presence of APL cells that did or did not have the characteristic translocation of APL, t(15;17). We also determined the effect of all-trans-retinoic acid on the expression of annexin II and the generation of cell-surface plasmin.. The expression of annexin II, as detected by a fluorescein-tagged antibody, was greater on leukemic cells from patients with APL than on other types of leukemic cells (mean fluorescence intensity, 6.9 and 2.9, respectively; P<0.01). The t(15;17)-positive APL cells stimulated the generation of cell-surface, t-PA-dependent plasmin twice as efficiently as the t(15;17)-negative cells. This increase in plasmin was blocked by an anti-annexin II antibody and was induced by transfection of t(15;17)-negative cells with annexin II complementary DNA. The t(15;17)-positive APL cells contained abundant messenger RNA for annexin II, which disappeared through a transcriptional mechanism after treatment with all-trans-retinoic acid.. Abnormally high levels of expression of annexin II on APL cells increase the production of plasmin, a fibrinolytic protein. Overexpression of annexin II may be a mechanism for the hemorrhagic complications of APL.

Topics: Adolescent; Adult; Annexin A2; Antibodies; Child; Child, Preschool; Female; Fibrinolysin; Fibrinolysis; Hemorrhagic Disorders; Humans; Leukemia; Leukemia, Promyelocytic, Acute; Male; Middle Aged; RNA, Messenger; Transcription, Genetic; Transfection; Translocation, Genetic; Tretinoin; Tumor Cells, Cultured

WEHI-3B D- cells differentiate in response to 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) but not to all-trans-retinoic acid (RA) or other inducing agents. Combinations of RA with 1,25-(OH)2D3 interact to produce synergistic differentiation of WEHI-3B D- cells. To determine factors involved in the synergistic interaction, expression of the 1,25-(OH)2D3 receptor (VDR) and retinoid receptors, RARalpha and RXRalpha, was measured. No VDR was detected in untreated WEHI-3B D- cells; however, RA and 1,25-(OH)2D3 when used as single agents caused a slight induction of the VDR and in combination produced a marked increase in the VDR. In contrast, no changes in RARalpha and RXRalpha were initiated by these compounds. An RAR-selective agonist combined with 1,25-(OH)2D3 produced synergistic differentiation of WEHI-3B D- cells, whereas an RXR-selective agonist did not. To gain information on the role of the VDR in the synergistic interaction, the VDR gene was transferred into WEHI-3B D+ cells, in which no VDR was detected and no synergism was produced. Expression of the VDR conferred differentiation responsiveness to 1,25-(OH)2D3 in WEHI-3B D+ cells. These findings suggest that (a) induction of VDR expression is a key component in the synergistic differentiation induced by 1,25-(OH)2D3 and RA and (b) RAR and not RXR must be activated for enhanced induction of the VDR and for the synergistic differentiation produced by RA and 1, 25-(OH)2D3.

Topics: Animals; Cell Differentiation; Dose-Response Relationship, Drug; Drug Combinations; Drug Synergism; Leukemia; Mice; Receptors, Calcitriol; Tretinoin; Tumor Cells, Cultured

Topics: Antineoplastic Agents; Cell Death; Cell Survival; Cysteine Endopeptidases; Cysteine Proteinase Inhibitors; Drug Therapy, Combination; Humans; Leukemia; Multienzyme Complexes; Proteasome Endopeptidase Complex; Tretinoin; Tumor Cells, Cultured

The Wilms tumor gene, WT1, encodes a zinc-finger DNA binding protein which is thought to function as a tissue specific transcription factor, regulating cell growth and differentiation. High expression of WT1 has been detected in a range of acute leukemias. To elucidate a role for WT1 in leukemogenesis, we transfected the monoblastic cell line U937, which lacks detectable levels of endogenous WT1, with two isoforms of WT1. We showed that, in contrast to U937 control cells, cells constitutively expressing either of the isoforms, WT1(-KTS) or WT1(+KTS), did not respond to differentiation induction by retinoic acid or vitamin D3, as judged by the capacity to reduce nitro blue tetrazolium and morphology. Although U937 cells expressing WT1 were hampered in their ability to differentiate on incubation with retinoic acid and vitamin D3, the induced G1/G0-accumulation was similar to differentiating control cells treated with inducers. Furthermore, distinct effects on the maturation process were indicated by downregulation of the myeloid cell surface makers CD13 and CD15, while the upregulation of CD14 and CD11c on WT1 transfected cells was similar to control cells upon incubation with retinoic acid and vitamin D3. Taken together our results demonstrate that a constitutive expression of WT1 in the leukemic cell line U937 leads to impairment of differentiation responses, indicating that a high expression of WT1 can contribute to the differentiation block of acute leukemia.

Topics: Cell Cycle; Cell Differentiation; Cell Division; Cell Line; Cell Survival; Cholecalciferol; Gene Expression Regulation, Developmental; Gene Expression Regulation, Neoplastic; Genes, Wilms Tumor; Humans; Integrin alphaXbeta2; Leukemia; Lipopolysaccharide Receptors; Monocytes; Transfection; Tretinoin

Topics: Adult; Antineoplastic Agents; Female; Humans; Leukemia; Middle Aged; Neoplasms, Second Primary; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Tretinoin

We have recently found that retinoic acids (RAs) evoke anticoagulant effect by upregulating thrombomodulin (TM) and downregulating tissue factor (TF) expression in acute promyelocytic leukemia (APL) and monoblastic leukemia cells. Two classes of nuclear RA receptors, termed retinoic acid receptors (RARs) and retinoid X receptors, have been identified. Each receptor class consists of three subtypes. We have used several synthetic retinoids to find which receptor subtypes are involved in the regulation of TM and TF expression in APL cells NB4, monoblastic leukemia cells U937 and human umbilical vein endothelial cells (HUVECs). Am80, which does not have a binding affinity to RARgamma, Ch55, which does not bind to cytoplasmic retinoic acid binding protein (CRABP), and a specific RARalpha agonist Ro40-6055, have shown to upregulate TM and downregulate TF in NB4 and U937 cells similar to all-trans RA (ATRA). A specific RARalpha antagonist Ro41-5253 efficiently suppressed the upregulation of TM by ATRA and Am80 in NB4 cells, U937 cells and HUVECs. In contrast, only when both RARalpha and RARbeta antagonists were preincubated, downregulation of TF by the retinoids was suppressed in NB4 cells. These results indicate the mechanically distinct transactivation and transrepression functions of RARs, the major role of RARalpha in TM upregulation by retinoids in leukemic cells and HUVECs and the cooperative role of RARalpha and RARbeta in TF downregulation by retinoids. This implies that synthetic retinoids will provide a very useful means to control distinct targets, TM and TF genes, at the level of transcription. Synthetic retinoids may develop as new type of antithrombotic agents which may change the character of cells as well as act as malignant cell differentiation inducers.

Topics: Anticoagulants; Antineoplastic Agents; Benzoates; Cell Differentiation; Chromans; Dibenzazepines; Humans; Leukemia; Membrane Proteins; Retinoids; Thrombomodulin; Thromboplastin; Tretinoin; Tumor Cells, Cultured; U937 Cells

Human leukemia K562 cells can be induced to erythroid differentiation when treated with a variety of compounds, including hemin, cytosine arabinoside and 5-azacytidine. Following erythroid induction, K562 cells express at high level gamma-globin and accumulate both Hb Portland and Hb Gower 1. In this paper we determined whether a combination treatment of K562 cells with suboptimal concentrations of cytosine arabinoside and retinoids lead to full expression of differentiated functions. Cell growth kinetics studies, intracellular detection of hemoglobin by benzidine staining and hemoglobin analysis by cellulose acetate were performed. The results obtained show that (a) retinoic acid and retinol are not able to induce differentiation of K562 cells and (b) cytosine arabinoside induces differentiation only when used at 100-300 nmol/l concentrations. In addition, our data demonstrate that erythroid differentiation of K562 occurs when 40 micromol/l of retinoic acid or retinol are added together with 75 nmol/l cytosine arabinoside.

Topics: Antimetabolites, Antineoplastic; Cell Differentiation; Cytarabine; Drug Synergism; Erythropoiesis; Humans; K562 Cells; Keratolytic Agents; Leukemia; Tretinoin; Vitamin A

In order to illustrate the possible roles of PML-RARalpha protein in arsenic trioxide (AsO3)-induced NB4 cell apoptosis.. Effects of As2O3 on the subcellular localization of PML-RARalpha in NB4 cells were studied.. (1) Anti-PML serum staining was reduced and PML granules emerged in the perinuclear cytoplasm in a diffuse pattern in HL-60 cells under As2O3 treatment; (2) abnormal PML/PML-RARalpha granules were decreased; (3) NB4 cells accumulated anti-PML serum staining granules in the cytoplasms were increased and similar accumulation also found in apoptotic cells; and (4) pretreatment with all-trans retinoic acid (ATRA) for 24 or 48 hours did not alter the As2O3 effects.. As2O3-induced apoptosis was independent of the retinoic acid signal pathway, and it might be regulated by PML/PML-RARalpha and/or other related genes.

Topics: Antineoplastic Agents; Apoptosis; Arsenic Trioxide; Arsenicals; HL-60 Cells; Humans; Intracellular Space; Leukemia; Nuclear Proteins; Oxides; Promyelocytic Leukemia Protein; Protein Transport; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Transcription Factors; Tretinoin; Tumor Suppressor Proteins

By using a differential display method, specific bands were selected from ladder PCR products derived from ATRA-dependent differentiated U937 cells, in comparison with those of untreated U937. By screening the cDNA library of ATRA-dependent differentiated U937 cells with one of the PCR products, we cloned the src-like adapter protein (SLAP). Northern blot analysis of U937 cells with or without ATRA treatment indicated that the SLAP mRNA was clearly induced by ATRA. The induction was inhibited by the addition of cycloheximide, indicating that ATRA acted indirectly through synthesis of other proteins. The SLAP mRNA was induced in HL60 and NB-4 but not in K562 or THP-1. Interestingly, these cells in which SLAP mRNA was induced by ATRA all showed ATRA-dependent cell differentiation. The relationship between SLAP and cell differentiation is unclear, but SLAP may transduce a signal for cell differentiation.

Topics: Adaptor Proteins, Signal Transducing; Blotting, Northern; Cell Differentiation; Cell Line; Gene Library; HL-60 Cells; Humans; Leukemia; Polymerase Chain Reaction; Proto-Oncogene Proteins pp60(c-src); RNA, Messenger; Transcription, Genetic; Tretinoin; Tumor Cells, Cultured

Recently, clinical application of gene technology in oncology and hematology has been markedly advanced. Pathogenesis of leukemic transformation has been thought that it was resulted from cumulation of activation or mutation in oncogenes or onco-suppressor genes. As a matter of fact, many specific chromosomal abnormalities in leukemias have been thought to be due to production of chimeric fusion gene by translocation and activation in some kinds of oncogenes under specific regulatory genes after translocation. In addition to those, inactivation of onco-suppressor genes, such as RB gene or p53 gene, may be also related to leukemogenesis in some leukemias. Laboratory examinations using molecular technology are being necessary for clinical diagnosis and treatment in many hematological disorders. The examinations detecting rearrangement of major BCR or minor BCR in Ph1 positive leukemias, TCR in T cell malignancy, immunoglobulin in B cell malignancy, PML-RAR alpha fusion gene in APL have become routine for diagnosis of some leukemias. Moreover, these examinations are useful for judgement of treatment effects and evaluation of minimal residual diseases. In this paper, we also discuss the usefulness and importance of these technology especially in stem cell transplantation and cytokine therapy, and the future possibility in this technology for gene therapy.

Topics: Cytokines; Genetic Engineering; Genetic Therapy; Hematopoietic Stem Cell Transplantation; Humans; Leukemia; Polymerase Chain Reaction; RNA, Messenger; Tretinoin

Topics: Adjuvants, Immunologic; Anti-Inflammatory Agents; Antigens, CD; Antigens, Neoplasm; Antineoplastic Agents; CD18 Antigens; Dexamethasone; Drug Screening Assays, Antitumor; Humans; Intercellular Adhesion Molecule-1; Leukemia; Mast Cells; Tretinoin; Tumor Cells, Cultured

The retinoblastoma tumor-suppressor gene, RB, has been implicated in tumor suppression, in regulation of the cell cycle, and in mediating cell differentiation. RB is necessary for hematopoiesis in mice, and aberrant RB-expression is associated with the progress and prognosis of leukemia. We have used antisense oligonucleotides, established clones stably expressing an antisense RB construct, and also established clones over expressing the retinoblastoma protein (pRb) to study the role of RB expression in monocytic differentiation induced by all-trans retinoic acid (ATRA) or 1-alpha-25-dihyroxycholecalciferol (Vit D3) in the monoblastic cell line U-937 and erythroid differentiation induced by transforming growth factor beta1 (TGFbeta1) and hemin in the erythroleukemic cell line K562. A reduction in pRb production in antisense RB-transfected U-937 clones was shown. Antisense oligonucleotides as well as expression of the antisense RB construct suppressed differentiation responses to ATRA or Vit D3, as judged by the capability to reduce nitro blue tetrazolium, by the appearance of monocyte-related cell surface antigens and by morphologic criteria. K562 cells showed decreased differentiation response to TGFbeta1, but not to hemin, when incubated with antisense oligonucleotides. U-937 antisense RB-transfected cells were also suppressed in their ability to upregulate levels of hypophosphorylated pRb when induced to differentiate. Although U-937 cells incubated with antisense oligonucleotides and clones expressing the antisense RB construct were hampered in their ability to differentiate on incubation with ATRA or Vit D3, the induced G0/G1-accumulation was similar to differentiating control cells treated with ATRA or Vit D3. Intriguingly, U-937 clones overexpressing RB were also inhibited in their differentiation response to ATRA or Vit D3 but not inhibited in their ability to respond with G0/G1 accumulation when induced with these substances. The results indicate that pRb plays a role in induced differentiation of U-937 cells as well as K562 cells involving mechanisms that, at least partially, are distinct from those inducing G1 accumulation.

Topics: Animals; Antigens, Differentiation; Antigens, Neoplasm; Calcitriol; Cell Differentiation; G1 Phase; Gene Expression Regulation, Leukemic; Genes, Retinoblastoma; Leukemia; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Lymphoma, Large B-Cell, Diffuse; Mice; Monocytes; Neoplasm Proteins; Oligonucleotides, Antisense; Retinoblastoma Protein; Transfection; Transforming Growth Factor beta; Tretinoin; Tumor Cells, Cultured

All-trans retinoic acid (RA) was previously shown to regulate the growth of gastric cancer cells derived from the cell line SC-M1. This study was designed to investigate the effect of RA on the sensitivity of SC-M1 cells to lymphokine-activated killer (LAK) activity. RA at the concentration range of 0.001-10 microM was shown to induce SC-M1 cells to exhibit resistance to LAK activity in a dose-dependent manner. A kinetics study indicated that a significantly increased resistance was detected after 2 days of co-culturing SC-M1 cells with RA and reached a maximum after 6 days of culture. Similar results were obtained from two other cancer cell lines: promyelocytic leukaemia HL-60 and hepatic cancer Hep 3B. A binding assay demonstrated that the binding efficacy between target SC-M1 cells and effector LAK cells was not altered by RA. Flow cytometric analyses revealed that RA exhibited no effect on the expression of cell surface molecules, including HLA class I and class II antigens, intercellular adhesion molecule-1 and -2, and lymphocyte function antigen-3. Cell cycle analysis revealed that culture of SC-M1 cells with RA resulted in an increase in G0/G1 phase and a decrease in S phase, accompanied by a decrease in cyclin A and cyclin B1 mRNA as determined by Northern blot analysis. Additionally, RA was shown to enhance the expression of retinoic acid receptor alpha (RAR alpha) in SC-M1 cells, and to have no effect on the expression of RARbeta or RARgamma. Taken together, these results indicate that RA can significantly increase gastric cancer cells SC-M1 to resist LAK cytotoxicity by means of a cytostatic effect through a mechanism relating to cell cycle regulation. The prevailing ideas, such as a decrease in effector to target cell binding, a reduced MHC class I antigen expression or an altered RARbeta expression, are not involved.

Topics: Antineoplastic Agents; Binding Sites; Blotting, Northern; Cell Adhesion Molecules; Cell Cycle; Cyclins; Cytotoxicity, Immunologic; Dose-Response Relationship, Drug; Flow Cytometry; HLA Antigens; Humans; Immunotherapy, Adoptive; Killer Cells, Lymphokine-Activated; Leukemia; Liver Neoplasms; Receptors, Retinoic Acid; Stomach Neoplasms; Tretinoin; Tumor Cells, Cultured

To explore the potential involvement of neurotrophins in the actions of retinoic acid (RA) on leukaemia differentiation, we examined the ability of RA to regulate the expression of neurotrophins and Trk receptors in several leukaemia cell lines. Expression of TrkA was dramatically induced by RA at both the mRNA and protein level in leukaemia cell lines K562 and KG-1. Furthermore, while no expression of trkB and trkC was detected, constitutive expression of nerve growth factor (NGF), neurotrophin-3 and neurotrophin-4/5 could be detected in leukemia cells. Our findings suggested that NGF/trkA may potentially be involved in the RA-induced differentiation of leukemia cells.

Topics: Antineoplastic Agents; Cell Differentiation; Humans; Leukemia; Nerve Growth Factors; Proto-Oncogene Proteins; Receptor Protein-Tyrosine Kinases; Receptor, trkA; Receptors, Nerve Growth Factor; RNA, Messenger; Tretinoin; Tumor Cells, Cultured; Up-Regulation

Geranylgeraniol, a polyprenylalcohol composing the side chain of vitamin K2 (VK2), was previously reported to be a potent inducer of apoptosis in tumor cell lines (Ohzumi H et al, J Biochem 1995; 117: 11-13). We examined the apoptosis-inducing ability of VK2 (menaquinone 3 (MK3), MK4 and MK5) and its derivatives such as phytonadione (VK1), as well as polyprenylalcohols with side chains of various lengths including farnesol (C15-OH; FO), geranylgeraniol (C20-OH; GGO), and geranylfarnesol (C25-OH; GFO) toward leukemia cells in vitro. MK3, MK4, MK5 and GFO (at 10 microM) showed a potent apoptosis-inducing activity for all freshly isolated leukemia cells tested and for leukemia cell lines such as NB4, an acute promyelocytic leukemia (APL)-derived cell line and MDS92, a cell line derived from a patient with myelodysplastic syndrome, although there were some differences depending on the cells tested. In contrast, VK1 showed no effect on any of the leukemia cells. The combination of MK5 plus all-trans retinoic acid (ATRA) resulted in enhanced induction of apoptosis in both freshly isolated APL cells and NB4 cells as compared to each reagent alone. These data suggest the possibility of using VK2 and its derivatives for the treatment of myelogenous leukemias, including APL.

Topics: Apoptosis; Bone Marrow; Diterpenes; Drug Synergism; Farnesol; Flow Cytometry; Gefarnate; Humans; Leukemia; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid; Leukemia, Promyelocytic, Acute; Molecular Structure; Myelodysplastic Syndromes; Structure-Activity Relationship; Tretinoin; Tumor Cells, Cultured; Vitamin K; Vitamin K 1; Vitamin K 2

Based on previously published observations regarding the protective effects of interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha) against gamma radiation, alkylating agents and ultraviolet radiation, we hypothesized that the protection against such DNA damaging treatments can be the result of a 'stress'-like response induced by these cytokines and mediated by early response cellular gene(s). By applying the mRNA differential display to RNA obtained from A549 lung carcinoma cell line that was incubated with 50 ng/ml IL-1 for 0, 1, 2, and 6 h, we identified several cDNA fragments that correspond to genes regulated by IL-1. The full length cDNA for one fragment was obtained using 5'RACE, cloned, sequenced, and found to be homologous to human A1, a Bcl-2-related gene. In this study, we report that the expression of human A1 is either absent or present at low levels in leukemic cells, while it is expressed in human bone marrow cells and abundant in peripheral blood progenitors. It is induced by IL-1 and TNF alpha in A549 lung carcinoma, bone marrow, and certain leukemic cells. A1 is also induced in leukemic cells during granulocytic or macrophage but not erythroid differentiation. In conclusion, this is the first demonstration that A1 is inducible by cytokines in human bone marrow and certain tumor cells as well as myeloid differentiation in leukemic cells.

Topics: Cell Differentiation; Cloning, Molecular; Gene Expression Regulation; Hematopoietic Stem Cells; Humans; Interleukin-1; Leukemia; Minor Histocompatibility Antigens; Proteins; Proto-Oncogene Proteins c-bcl-2; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

Nuclear receptors comprise a large family of ligand-dependent transcription factors that display considerable specificity in and selectivity in regulating the genetic programs they ultimately influence. The response to retinoic acid (RA) is mediated by two families of transcription factors which include the retinoic acids receptors (RARs) and the retinoid X receptors (RXRs). In human acute promyelocytic leukemia (APL), RAR alpha becomes an activated oncogene as a consequence of its fusion to the PML locus. Because patients with APL can be induced into remission with high dose RA therapy, we propose that PML-RAR is a new class of dominant negative oncogene that disrupts a structure that includes at least five other proteins. This mega-complex, referred to as a "POD", is disrupted in leukemic cells expressing the oncoprotein and is reassembled following high dose RA therapy in both cell culture an in patients.

Topics: Aging; Animals; Antineoplastic Agents; Cells, Cultured; Drosophila; Gene Expression Regulation; Humans; Leukemia; Leukemia, Promyelocytic, Acute; Models, Genetic; Neoplasm Proteins; Nuclear Proteins; Oncogenes; Promyelocytic Leukemia Protein; Receptors, Retinoic Acid; Retinoid X Receptors; Transcription Factors; Tretinoin; Tumor Cells, Cultured; Tumor Suppressor Proteins

The relation between resistance to anticancer drugs and resistance to apoptosis has been investigated in the human leukemic cell line(KY-821) and its drug-resistant sublines. Under serum depletion conditions, drug-resistant cell lines showed apoptotic resistance when compared with the parental cell line. Drug resistant cell lines also showed resistance to apoptosis when treated with all-trans retinoic acid. DNA fragmentation was low in drug resistant cell lines under both stimulations. Flowcytometry analysis did not show any alterations of the Fas antigen, p53, bcl-2 and c-myc protein expression toward inhibition of apoptotic response in drug-resistant sublines. These results indicate that drug-resistant leukemic cells still show resistance to apoptosis-inducing stimulation such as poor nutrition and differentiation-inducing agents.

Topics: Antineoplastic Agents; Apoptosis; Blotting, Western; Culture Media, Serum-Free; DNA, Neoplasm; Drug Resistance, Neoplasm; Electrophoresis; fas Receptor; Humans; Leukemia; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-myc; Tretinoin; Tumor Cells, Cultured; Tumor Suppressor Protein p53

The capabilities of 1alpha, 25-dihydroxyvitamin D3 (1,25(OH)2D3), and two novel vitamin D analogues, EB1089 and KH1060, to induce the differentiation of two established leukaemia cell lines, U937 and HL-60, were assessed alone or in combination with the retinoid compounds, 9-cis retinoic acid (9-cis RA) and all-trans retinoic acid (ATRA). The vitamin D derivatives acted to increase the differentiation of U937 and HL-60 cell cultures in a dose-dependent manner, as determined by nitroblue tetrazolium (NBT) reduction, with EB1089 and KH1060 being more effective than the native hormone. As an additional index of leukaemic cell differentiation, induction of expression of the phenotypic cell surface antigen, CD14, and the beta2-integrins, CD11b and CD18 by the vitamin D and retinoid compounds were monitored using fluorescence activated cell sorting (FACS) analyses. Following 96-hr treatment of U937 and HL-60 cells with 5 x 10(-10) M of the vitamin D derivatives, a striking increase in CD14 antigen expression was apparent, indicating the promotion by these compounds of a monocyte/macrophage lineage of cells. CD11b and CD18 antigen expression were also raised above control levels. In contrast, both retinoid compounds used at the higher concentration of 1 x 10(-8) M were not effective inducers of CD14 antigen expression. However, CD11b and CD18 were both readily increased in U937 and HL-60 cell cultures. Treatment of U937 cell cultures with the vitamin D compounds and the retinoids resulted in cooperative effects on induction of differentiation, with correlation by both NBT reduction and FACS analyses of CD14 antigen expression. The presence of 9-cis RA or ATRA appeared to contribute to the further increase of CD14 in these cells. HL-60 cell cotreatment with these compounds also displayed enhanced cooperative effects in phagocytic function by NBT reduction. However, analysis of CD14 revealed a dramatic diminution in HL-60 cells treated with the combinations of the vitamin D derivatives and the retinoids. Assessment of HL-60 cell morphology treated with these combinations demonstrated the presence of a mixed population of monocytes and granulocytes. CD11b and CD18 antigen expression was also enhanced in both cell lines with cotreatment. The ability of EB1089 and KH1060 to induce leukaemic cell differentiation may provide an additional option for therapeutic use alone or together with other differentiation agents such as 9-cis RA or ATRA.

Topics: Alitretinoin; Antigens, CD; Antineoplastic Agents; Calcitriol; Cell Differentiation; Dose-Response Relationship, Drug; Drug Interactions; Flow Cytometry; HL-60 Cells; Humans; Leukemia; Tretinoin; Tumor Cells, Cultured

Retinoic acid (RA) induces differentiation, followed by apoptosis in acute promyelocytic leukemia (APL) cells, both in vitro and in patients. One problem in understanding these mechanisms is to distinguish molecular events leading to differentiation from those leading to apoptosis. We have identified a leukemic cell line, PLB-985, where RA directly induces apoptosis with no morphologic, genetic, or cell-surface marker evidence of differentiation. These cells differentiate following dimethyl sulfoxide (DMSO), but not RA, treatment. Two-color flow cytometry showed no alteration of the cell cycle after RA treatment, and cell-surface marker analysis of CD11a, CD11b, and CD13 showed no modulation typical of differentiating cells. RNA expression of myeloblastin and transglutaminase, genes regulated by RA-induced differentiation in NB4 cells, was unchanged by RA treatment. Instead, RA induced apoptosis, as shown by typical apoptotic morphological features, genomic DNA laddering, and positive labeling in the TUNEL assay. We found that induction of apoptosis in this model requires a different pattern of retinoid receptor binding and transcriptional activation than is seen in APL cells. As previously described, treatment with retinoid receptor-selective ligands showed that stimulation of RAR alone is sufficient to induce differentiation and apoptosis in NB4 cells, and that stimulation of RXR has no effect on the parameters analyzed. In PLB-985 cells, on the other hand, apoptosis was induced only upon costimulation of both RAR and RXR. Stimulation of either receptor alone had no effect on the cells. Consistent with these findings, bcl-2 RNA and protein levels were downregulated after stimulation of both RAR and RXR, but not with an RAR-specific ligand alone, as in NB4 cells. The expression of several other bcl-2 family members (bcl-X, ich-1, bax, bag, and bak ) and retinoid receptors (RARalpha, RXRalpha, and RXRbeta) was not affected by treatment with RAR- and/or RXR-activating retinoids; RARbeta RNA was undetectable before and after retinoid treatment. Thus, our cell model provides a useful tool in determining the genetic events mediating apoptosis as a response to RA, unobscured by events implicated in differentiation.

Topics: Apoptosis; Cell Differentiation; Humans; Keratolytic Agents; Leukemia; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Retinoid X Receptors; Signal Transduction; Transcription Factors; Tretinoin; Tumor Cells, Cultured

We have recently found that all-trans retinoic acid (ATRA) upregulates thrombomodulin (TM) and downregulates tissue factor (TF) expression in acute myelogenous leukemia (AML) M3 cells (NB4) and acute monoblastic leukemia cells (U937) (Koyama et al, Blood 84:3001, 1994). We have further investigated the effects of ATRA on leukemic cells freshly isolated from patients at diagnosis. Increase of TM antigen was documented in all AML cells: M0 (n = 1), M2 (n = 5), M3 (n = 3), M4 (n = 3), M5 (n = 3), and M6 (n = 1). Decrease of TF antigen was observed in 4 M2, 1 M4, and all M3 and M5 patients. However, no TM and TF antigens were detected in all chronic lymphocytic leukemia cells (n = 3) with or without ATRA treatment. Changes of TM and TF antigen levels were associated with those of TM and TF cofactor levels on the cell surface. A stereoisomer of RA, 9-cis RA, is a high-affinity ligand for the RA receptors (RARs) and the retinoid X receptors, although ATRA and another isomer, 13-cis RA, solely bind to RARs. We have also studied the effects of 9-cis RA and 13-cis RA on the expressions of TM and TF in NB4 and U937 cells. A relatively wide range of 9-cis RA concentrations (0.01 to 1 mumol/L) compared with ATRA was optimal for prolongation of normal plasma-based recalcification time (reduction of cell surface TF activity), decrease of TF antigen, and increase of TM antigen on the surface and in the lysates of NB4 and U937 cells. Western blot analysis under nonreducing conditions showed that both ATRA and 9-cis RA markedly induced the prominent band at 75 kD of TM and reduced the band at 45 kD of TF. Northern blot analysis has shown similar changes of mRNA levels, which indicates that RAs regulate TM and TF expression in leukemic cells at transcriptional levels. Anticoagulant effects of ATRA, ie, upregulation of TM expression and downregulation of TF expression, are applied not only to established cell lines of specific subtypes (M3 and M5) but also to more universal AML (most cases of M3 and M5 and a part of the other types of AML) cells freshly isolated from patients. 9-cis RA may be more effective than ATRA as an inducer of differentiation of AML M3 cells and as an anticoagulant agent for patients with certain types of AML as well.

Topics: Anticoagulants; Base Sequence; Cell Separation; Cysteine Endopeptidases; Flow Cytometry; Gene Expression Regulation, Leukemic; Humans; Isotretinoin; Leukemia; Leukemia, Monocytic, Acute; Leukemia, Promyelocytic, Acute; Lymphoma, Large B-Cell, Diffuse; Molecular Sequence Data; Neoplasm Proteins; Neoplastic Stem Cells; Receptors, Retinoic Acid; Thrombomodulin; Thromboplastin; Tretinoin; Tumor Cells, Cultured

We previously reported that CD38 characterized as an ecto-enzyme of NAD+ glycohydrolase (NADase) was specifically induced by retinoic acid (RA) in human promyelocytic leukemia HL-60 cells and that anti-CD38 monoclonal antibody (mAb) induced tyrosine phosphorylation of cellular proteins in the RA-differentiated cells. In the present study, we found that CD38/NADase was induced in human monocytic leukemia THP-1 cells not only by RA but also by dibutyryl cAMP, which had no effect on the induction of CD38 in HL-60 cells. Similarly in the RA-differentiated HL-60 cells, tyrosine phosphorylation by anti-CD38 mAb was also observed in the CD38-expressing THP-1 cells, regardless of whether CD38 was induced by RA or dibutyryl cAMP. Such tyrosine phosphorylation was, however, not observed in human lymphoblastic leukemia Jurkat cells which had been treated by RA to produce CD38. Thus, the induction of CD38/NADase appeared to be not limited for RA-dependent differentiation and not always linked to protein-tyrosine phosphorylation in human leukemic cell lines.

Topics: ADP-ribosyl Cyclase; ADP-ribosyl Cyclase 1; Antibodies, Monoclonal; Antigens, CD; Antigens, Differentiation; Bucladesine; Cell Differentiation; Cell Line; HL-60 Cells; Humans; Kinetics; Leukemia; Membrane Glycoproteins; N-Glycosyl Hydrolases; NAD+ Nucleosidase; Phosphoproteins; Phosphorylation; Phosphotyrosine; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured

ERV3 (HERV-R) is a complete human endogenous retrovirus located on the long arm of chromosome 7. LTR-env-gene-spliced mRNA of 9 and 3.5 Kb is widely expressed in human tissues and cells, but gag-pol mRNA has not been found. Further, the env gp70 gene contains an open reading frame throughout its length and its expression has recently been detected as a full-length protein. The highest expression of ERV3 detected so far is in placenta and the lowest in cytotrophoblasts and choriocarcinoma cell lines. In this report we have studied ERV3 mRNA and protein expression in the human monoblastic cell line U-937 during differentiation into monocytes/macrophages. Differentiation of U-937 cells was induced by 1,25a-dihydroxyvitamin D3 (vitD3), retinoic acid (RA), gamma interferon (IFN-gamma) and phorbol-myristate-acetate (PMA-TPA). The expression of ERV3 env mRNA was found to be differentiation-associated, with high expression detected in the late stages of monocytic development. Using TPA, the expression of ERV3 env was detected as 9- and 3.5-kb transcripts by Northern blotting, as mRNA by in situ hybridization and as a cytoplasmic 65-kDa protein by immunofluorescence and Western blots. Low levels of basal expression were found, with up-regulation of both message and protein at 24 to 48 hr after addition of TPA. Induction with vitD3, IFN-gamma and RA produced higher levels of mRNA at earlier time points. It is concluded that the U-937 cell line represents an excellent model system for further studies to study the relationship between ERV3 expression and cellular differentiation.

Topics: Calcitriol; Cell Differentiation; Gene Products, env; Humans; Interferon-gamma; Leukemia; Monocytes; Retroviridae; RNA, Messenger; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured

Retinoids induce myeloblastic leukemia (HL-60) cells to differentiate into granulocytes, which subsequently die by apoptosis. Retinoid action is mediated through at least two classes of nuclear receptors: retinoic acid receptors, which bind both all-trans retinoic acid and 9-cis retinoic acid, and retinoid X receptors, which bind only 9-cis retinoic acid. Using receptor-selective synthetic retinoids and HL-60 cell sublines with different retinoid responsiveness, we have investigated the contribution that each class of receptors makes to the processes of cellular differentiation and death. Our results demonstrate that ligand activation of retinoic acid receptors is sufficient to induce differentiation, whereas ligand activation of retinoid X receptors is essential for the induction of apoptosis in HL-60 cell lines.

Topics: Apoptosis; Benzoates; Binding, Competitive; Cell Differentiation; Cell Division; Dose-Response Relationship, Drug; Hematopoietic Stem Cells; Humans; Leukemia; Receptors, Retinoic Acid; Retinoid X Receptors; Retinoids; Signal Transduction; Structure-Activity Relationship; Tetrahydronaphthalenes; Transcription Factors; Tretinoin; Tumor Cells, Cultured

The effects of elevated levels of cyclic AMP induced by cholera toxin (CTx) were investigated on the differentiated promyelomonocytic cell line U937. After CTx treatment, the initial inhibition of the oxidative burst induced by N-formylmethionyl-leucyl-phenylalanine (FMLP) was followed by a progressive increase over 20 h, resulting in 4-6-fold potentiation of the initial burst. Various cyclic-AMP-elevating agents produced similar potentiation of the FMLP- or C5a-induced oxidative burst, but the phorbol 12-myristate 13-acetate-induced oxidative burst was not affected by CTx pretreatment of cells. Furthermore, the increase in arachidonate release and intracellular Ca2+ triggered by FMLP were amplified after CTx treatment. ADP-ribosylation of Gi alpha subunits catalysed by pertussis toxin was slightly increased after CTx treatment, despite similar immunoreactivity of the alpha subunit of Gi2. FMLP binding sites present in CTx-treated membranes were 3-6 times more abundant than in control membranes. Expression of mRNAs encoding the FMLP receptor and one of its related receptors were enhanced after CTx treatment of both undifferentiated and undifferentiated U937 cells. In parallel, after undifferentiated cells were treated with CTx, they were able to increase intracellular Ca2+, but not the oxidative burst, in response to FMLP. These data demonstrate that CTx, by increasing cyclic AMP, enhances the expression of chemotactic receptors independently of U937 cell differentiation.

Topics: Amino Acid Sequence; Arachidonic Acid; Base Sequence; Calcitriol; Calcium; Cell Differentiation; Cholera Toxin; Cyclic AMP; Humans; Intracellular Fluid; Leukemia; Macrophages; Molecular Sequence Data; N-Formylmethionine Leucyl-Phenylalanine; Receptors, Formyl Peptide; Receptors, Immunologic; Receptors, Peptide; Respiratory Burst; RNA, Messenger; Tretinoin; Tumor Cells, Cultured

The lactoferrin gene is highly expressed in many different tissues, and its expression is controlled by different regulators. In this report, we have defined a retinoic acid response element (RARE) in the 5'-flanking region of the lactoferrin gene promoter. The lactoferrin-RARE is composed of two AGGTCA-like motifs arranged as a direct repeat with 1-bp spacing (DR-1). A gel retardation assay demonstrated that it bound strongly with retinoid X receptor (RXR) homodimers and RXR-retinoic acid receptor (RAR) heterodimers as well as chicken ovalbumin upstream promoter transcription factor (COUP-TF) orphan receptor. In CV-1 cells, the lactoferrin-RARE linked with a heterologous thymidine kinase promoter was strongly activated by RXR homodimers in response to 9-cis-retinoic acid (9-cis-RA) but not to all-trans-RA. When the COUP-TF orphan receptor was cotransfected, the 9-cis-RA-induced RXR homodimer activity was strongly repressed. A unique feature of the lactoferrin-RARE is that it has an AGGTCA-like motif in common with an estrogen-responsive element (ERE). The composite RARE/ERE contributes to the functional interaction between retinoid receptors and the estrogen receptor (ER) and their ligands. In CV-1 cells, cotransfection of the retinoid and estrogen receptors led to mutual inhibition of the other's activity, while an RA-dependent inhibition of ER activity was observed in breast cancer cells. Furthermore, the lactoferrin-RARE/ERE showed differential transactivation activity in different cell types. RAs could activate the lactoferrin-RARE/ERE in human leukemia HL-60 cells and U937 cells but not in human breast cancer cells. By gel retardation analyses, we demonstrated that strong binding of the endogenous COUP-TF in breast cancer cells to the composite element contributed to diminished RA response in these cells. Thus, the lactoferrin-RARE/ERE functions as a signaling switch module that mediates multihormonal responsiveness in the regulation of lactoferrin gene expression.

Topics: Base Sequence; COUP Transcription Factor I; DNA-Binding Proteins; Estrogens; Female; Gene Expression Regulation; Humans; Lactoferrin; Leukemia; Molecular Sequence Data; Promoter Regions, Genetic; Protein Binding; Receptors, Retinoic Acid; Recombinant Proteins; Retinoid X Receptors; Signal Transduction; Transcription Factors; Transcription, Genetic; Tretinoin; Tumor Cells, Cultured

Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme which has been shown to play a role in the differentiation of haematopoietic cells. We report here that neutrophils are the first nucleated mammalian cell type demonstrated to be devoid of immunoreactive PARP. Both NB4 acute promyelocytic leukaemia and HL-60 (acute myelocytic leukaemia) cells were differentiated into non-malignant neutrophils with all-trans-retinoic acid (ATRA). Western blot analysis demonstrated that ATRA had no effect on PARP expression in HL-60 cells. However, PARP was completely down-regulated in NB4 cells within 36 h of treatment initiation. This decrease in PARP polypeptide coincided with growth arrest and preceded the appearance of neutrophilic differentiation features. NB4 cells require a combination of 1,25-dihydroxyvitamin D3 (1,25-D3) and phorbol 12-myristate 13-acetate (PMA) to differentiate completely into monocyte/macrophages, whereas HL-60 cells can be made to differentiate by combined or single agents. PARP expression was up-regulated 90-fold when NB4 cells were treated with PMA and 1,25-D3 together, and this increase accompanied expression of the monocyte/macrophage phenotype. Only modest changes in PARP expression were observed when each agent was used alone in NB4 cells or when HL-60 cells were differentiated along the monocyte/macrophage pathway. In addition, PARP activity was modulated in a pattern similar to protein levels when NB4 cells were induced to differentiate along the neutrophilic and monocyte/macrophage pathways. This suggests that the activity of PARP may be controlled through regulation of protein levels during NB4 cell differentiation. We conclude that PARP levels are dramatically modulated during monocyte/macrophage and neutrophilic differentiation. On the basis of the tremendous changes in PARP polypeptide and total activity during myeloid differentiation, we propose that modulation of PARP gene expression is required for cellular maturation in both lineages.

Topics: Calcitriol; Cell Differentiation; Cell Division; Humans; Leukemia; Monocytes; Neutrophils; Poly(ADP-ribose) Polymerases; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured

Retinoic acid-induced differentiation of human leukemic HL-60 cells is accompanied with the early induction of an ecto-enzyme of NAD+ glycohydrolase (NADase), which has recently been identified as human leukocyte cell surface antigen CD38 [Kontani, K. et al. (1993) J. Biol. Chem. 268, 16895-16898]. The terminal cell differentiation attendant upon the cell growth arrest was, but the early induction of CD38 NADase activity was not, inhibited by prior treatment of HL-60 cells with pertussis toxin, which catalyzed ADP-ribosylation of the membrane-bound alpha beta gamma-trimeric GTP-binding proteins. The prior treatment was, however, not essential for the toxin-induced inhibition of the cell differentiation; the inhibition by the addition of pertussis toxin was still observed even after retinoic acid-induced expression of CD38 antigen. This suggested that a pertussis toxin-sensitive mechanism was involved in a late process of cell differentiation. Indeed, HL-60 cells appeared to secrete a differentiation-supporting factor in response to retinoic acid, since the cell differentiation was accelerated and potentiated upon culture of the cells in a conditioned medium prepared from retinoic acid-treated cells. The action of the differentiation-supporting factor was destroyed by heating and markedly attenuated in pertussis toxin-pretreated HL-60 cells. Thus, the whole process of the retinoic acid-induced cell differentiation appeared to consist of two distinguishable periods in terms of sensitivity to pertussis toxin; the toxin-insensitive early period characterized by the induction of CD38 NADase activity and the toxin-sensitive late period in which the secretion of a differentiation-supporting factor might be involved.

Topics: ADP-ribosyl Cyclase; ADP-ribosyl Cyclase 1; Antigens, CD; Antigens, Differentiation; Cell Differentiation; Humans; Leukemia; Membrane Glycoproteins; Neoplasm Proteins; Pertussis Toxin; Tretinoin; Tumor Cells, Cultured; Virulence Factors, Bordetella

Induction of apoptosis in lymphocytes, which may account for the therapeutic effects of glucocorticoids in various diseases including leukemia, depends on the glucocorticoid receptor. However, the events leading from the activated receptor to cell lysis are not understood. A prevailing hypothesis postulates induction of so-called 'lysis genes' by the activated receptor. In this study, we show that an activation-deficient glucocorticoid receptor mutant is as effective as the wild-type receptor in repression of AP-1 activity, inhibition of interleukin-2 production, inhibition of c-myc expression and induction of apoptosis. Furthermore, we show that retinoic acid can also induce apoptosis in these cells through the retinoic acid receptor, whose repressive functions but not target site specificity, are similar to those of the glucocorticoid receptor. Therefore, the primary effect of the receptor in glucocorticoid-mediated apoptosis correlates with transcriptional repression rather than activation and could be mediated by interference with other transcription factors required for cell survival.

Topics: Amino Acid Sequence; Apoptosis; Cell Division; Dexamethasone; Gene Expression Regulation; Glucocorticoids; Humans; Interleukin-2; Leukemia; Molecular Sequence Data; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; Proto-Oncogene Proteins c-myc; Receptors, Glucocorticoid; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Signal Transduction; T-Lymphocytes; Transcription Factor AP-1; Transcriptional Activation; Tretinoin; Tumor Cells, Cultured

p21WAF/CIP1/SDI1 is a recently identified gene expressed in cells harboring wild-type but not mutant p53 gene. It encodes a nuclear protein of 21 kD which inhibits cyclin-dependent kinase activity. Constitutive p21WAF1/CIP1/SDI1 mRNA expression was detected in neoplastic cells from patients with various hematological malignancies as well as in normal bone marrow mononuclear cells and in myeloid and lymphoid cell lines independent of their p53 status. Induced differentiation of the p53-deficient promyelocytic HL-60 cells along the monocytic lineage by phorbol ester or 1a,25 dihydroxyvitamin D3 resulted in a marked increase of both p21WAF1/CIP1/SDI1 mRNA and protein expression due to enhanced mRNA stability. Differentiation towards the granulocytic lineage by all-trans retinoic acid or dimethylsulfoxide failed to produce this effect. p21WAF1/CIP1/SDI1 is an immediate early gene since its upregulation occurred independently of de novo protein synthesis. The induction of p21WAF1/CIP1/SDI1 expression and its regulation in p53-deficient differentiating leukemic cells support the idea of an additional, p53-independent role of p21WAF1/CIP1/SDI1 in human hematopoiesis.

Topics: Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Dimethyl Sulfoxide; Gene Expression Regulation, Neoplastic; Granulocytes; Humans; Leukemia; Monocytes; RNA, Messenger; Tetradecanoylphorbol Acetate; Transcription, Genetic; Tretinoin; Tumor Cells, Cultured; Tumor Suppressor Protein p53

We have identified and characterized a previously unrecognized form of acute leukemia that shares features of both myeloid and natural killer (NK) cells. From a consecutive series of 350 cases of adult de novo acute myeloid leukemia (AML), we identified 20 cases (6%) with a unique immunophenotype: CD33+, CD56+, CD11a+, CD13lo, CD15lo, CD34+/-, HLA-DR-, CD16-. Multicolor flow cytometric assays confirmed the coexpression of myeloid (CD33, CD13, CD15) and NK cell-associated (CD56) antigens in each case, whereas reverse transcription polymerase chain reaction (RT-PCR) assays confirmed the identity of CD56 (neural cell adhesion molecule) in leukemic blasts. Although two cases expressed CD4, no case expressed CD2, CD3, or CD8 and no case showed clonal rearrangement of genes encoding the T-cell receptor (TCR beta, gamma, delta). Leukemic blasts in the majority of cases shared unique morphologic features (deeply invaginated nuclear membranes, scant cytoplasm with fine azurophilic granularity, and finely granular Sudan black B and myeloperoxidase cytochemical reactivity) that were remarkably similar to those of acute promyelocytic leukemia (APL); particularly the microgranular variant (FAB AML-M3v). However, all 20 cases lacked the t(15;17) and 17 cases tested lacked the promyelocytic/retinoic acid receptor alpha (RAR alpha) fusion transcript in RT-PCR assays; 12 cases had 46,XX or 46,XY karyotypes, whereas 2 cases had abnormalities of chromosome 17q: 1 with del(17)(q25) and the other with t(11;17)(q23;q21) and the promyelocytic leukemia zinc finger/RAR alpha fusion transcript. All cases tested (6/20), including the case with t(11;17), failed to differentiate in vitro in response to all-trans retinoic acid (ATRA), suggesting that these cases may account for some APLs that have not shown a clinical response to ATRA. Four of 6 cases tested showed functional NK cell-mediated cytotoxicity, suggesting a relationship between these unique CD33+, CD56+, CD16- acute leukemias and normal CD56+, CD16- NK precursor cells. Using a combination of panning and multiparameter flow cytometric sorting, we identified a normal CD56+, CD33+, CD16- counterpart cell at a frequency of 1% to 2% in the peripheral blood of healthy individuals. Our studies suggest that this form of acute leukemia may arise from transformation of a precursor cell common to both the myeloid and NK cell lineages; thus we propose the designation myeloid/NK acute leukemia. Recognition of this new leukemic entity w

Topics: Acute Disease; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Antigens, Differentiation, T-Lymphocyte; Base Sequence; CD56 Antigen; Cell Differentiation; Cytotoxicity, Immunologic; Diagnostic Errors; HLA-DR Antigens; Humans; Immunophenotyping; Killer Cells, Natural; Leukemia; Leukemia, Promyelocytic, Acute; Molecular Sequence Data; Receptors, IgG; Receptors, Retinoic Acid; Sialic Acid Binding Ig-like Lectin 3; Tretinoin

Topics: Antineoplastic Agents; Drug Administration Schedule; Drug Resistance; Humans; Leukemia; Leukemia, Promyelocytic, Acute; Leukocytosis; Multiple Myeloma; Tretinoin

The ATP-dependent glutathione S-conjugate export pump, named GS-X pump, has been shown to eliminate a potentially cytotoxic glutathione-platinum (GS.Pt) complex from tumor cells, thereby modulating glutathione (GSH)-associated resistance to cis-diamminedichloroplatinum(II) (cisplatin) (Ishikawa, T., and Ali-Osman, F. (1993) J. Biol. Chem. 268, 20116-20125). The present study provides evidence that the GS-X pump is functionally overexpressed in cisplatin-resistant human promyelocytic leukemia HL-60 (HL-60/R-CP) cells, in which the cellular GSH level was substantially enhanced. Indeed, the rate of ATP-dependent transport of the GS.Pt complex, measured with plasma membrane vesicles, was about 4-fold greater in HL-60/R-CP cells than in HL-60 cells. Three membrane proteins with apparent molecular masses of 200, 110, and 70 kDa were overexpressed in HL-60/R-CP cells, whereas P-glycoprotein (MDR1) was not immunologically detected in the membrane preparations from resistant and sensitive cells. Unlike in HL-60 cells, increased numbers of intracellular vesicles were observed in the cytoplasm of HL-60/R-CP cells. Fluorescence microscopy with syn-(CICH2,CH3)-1,5-diazabicyclo-[3.3.0]-octa-3,6-dione-2,8-dione (monochlorobimane) revealed that the fluorescent glutathione S-conjugate accumulated in intracellular vesicles of the cisplatin-resistant cells in an energy-dependent manner. The GS-X pump is suggested to contribute to vesicle-mediated excretion of GSH-drug conjugates from cells. In addition, both HL-60 and HL-60/R-CP cells underwent cell differentiation in response to 12-O-tetradecanoylphorbol-13-acetate, retinoic acid, and dimethyl sulfoxide, resulting in proliferation arrest as well as a remarkable decrease in the c-myc mRNA levels. After cell differentiation, a significant decrease was observed in the activity of ATP-dependent transport of the GS.Pt complex in membrane vesicles prepared from both HL-60/R-CP and HL-60 cells. These results suggest that the expression of the GS-X pump in both cisplatin-resistant and -sensitive cells is related to cell proliferation.

Topics: Adenosine Triphosphate; Biological Transport; Carrier Proteins; Cell Differentiation; Cisplatin; Dimethyl Sulfoxide; Down-Regulation; Drug Resistance; Glutathione; Humans; Leukemia; Membrane Proteins; Membrane Transport Proteins; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured

Topics: Animals; Cell Differentiation; Cell Division; Gene Expression Regulation, Neoplastic; Genes, fms; Genes, Retinoblastoma; Humans; Leukemia; Leukemia, Promyelocytic, Acute; Male; Mice; Mice, SCID; Neoplasm Transplantation; Receptor, Macrophage Colony-Stimulating Factor; Tretinoin; Tumor Cells, Cultured; Vitamin A; Vitamin D

Annexin VIII is a calcium- and phospholipid-binding protein with anticoagulant activity. Annexin VIII mRNA was found to be specifically expressed in acute promyelocytic leukemia (APL) cells; it was not found in other types of acute myeloid leukemia (AML) nor in lymphoid malignancies. Using Northern blot analysis we investigated annexin VIII expression in 142 continuous human leukemia and lymphoma cell lines at the mRNA level. While the only APL cell line, NB-4, was indeed positive, other cell lines also displayed annexin VIII mRNA: 4/22 myeloid cell lines, 8/23 monocytic cell lines, 2/8 megakaryoblastic cell lines, 5/26 lymphoma-derived cell lines, 2/10 myeloma cell lines and 1/44 lymphoid leukemia cell lines. The strongest expression was seen in NB-4 and in the Hodgkin's disease derived cell line HDLM-2. Treatment of NB-4 cells with all-trans retinoic acid (ATRA) or the phorbol ester TPA induced terminal differentiation and down-regulated annexin VIII mRNA expression rapidly within a few hours; vitamin D3 was ineffective in this regard; the protein kinase C activator Bryostatin 1 up-regulated the expression. A panel of initially negative cell lines could not be induced by any of these biomodulators to transcribe annexin VIII. The half-life (T1/2) of annexin VIII mRNA was about 3-4 h using actinomycin D as transcription inhibitor. Treatment with ATRA or TPA prior to exposure to actinomycin shortened the T1/2 to 2 h while Bryostatin 1 extended it to 6h. As 21/141 non-APL cell lines were positive, annexin VIII cannot be used as a marker gene for APL cells; however, it might be associated with myelomonocytic or erythro-megakaryoblastic precursor cells. Annexin VIII gene expression might play a unique role in the proliferation and/or differentiation of leukemic cells and could be associated with the particular abnormal hemostasis of some leukemias.

Topics: Annexins; Blotting, Northern; Bryostatins; Cell Differentiation; Cholecalciferol; Dactinomycin; Gene Expression Regulation, Neoplastic; Half-Life; Humans; Lactones; Leukemia; Leukemia, Myeloid; Leukemia, Promyelocytic, Acute; Lymphoma; Macrolides; RNA, Messenger; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured

Cell surface expression of leukosialin (sialophorin, CD43 antigen) on human neoplastic hematopoietic cell lines K-562, U-937, HL-60 and REH was determined with the aid of a new CD43 monoclonal antibody (Bra7G) by the immunochemical (radioimmunoprecipitation, immunoblotting) and immunocytofluorometric techniques. Interferon-gamma and TNF-alpha were utilized as the "physiological" inducers of differentiation-associated markers. The "non-physiological" inducer phorbol ester PMA induced down-regulation of leukosialin cell surface expression on immature erythroid-myeloid leukemia cell line K-562, but up-regulation of CD43 antigen on the promyelocyte leukemia cell line HL-60 and, to a lesser extent on the monocyte-like U-937 and CALLA+ ALL cell line REH. Retinoic acid down-regulated leukosialin on both U-937 monocyte-like cells and the CALLA+ ALL cell line REH. In contrast to these data, interferon-gamma, TNF-alpha, retinoic acid and 1,25(OH)2-vitamin D3 induced the up-regulation of leukosialin in a promyelocytic leukemia cell line HL-60.

Topics: Antigens, CD; Calcitriol; Cytokines; Flow Cytometry; Humans; Immunoblotting; Interferon-gamma; Leukemia; Leukosialin; Radioimmunoassay; Sialoglycoproteins; Tretinoin; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

The individual and combined effects of heat shock, all-trans retinoic acid and 1,25-dihydroxyvitamin D3 on inhibition of cell growth and initiation of differentiation were investigated on U937 human leukemia cells. Incubation of U937 cells at 43 degrees C for 1 h did not affect cell viability but induced a reduction of cell growth and the emergence of a differentiated phenotype, characterized by the acquisition of chemiluminescent responses to various oxidative burst inducers and by the capacity to produce IL-6 in response to bacterial lipopolysaccharide. Heat shock alone, therefore, appears to be an efficient inducer of cell differentiation. In addition, heat shock primed the cells to respond more efficiently to the action of retinoic acid and vitamin D, and amplified the phenotypic changes initiated by pretreatment of U937 cells with these agents.

Topics: Calcitriol; Cell Differentiation; Cell Division; Hot Temperature; Humans; Kinetics; Leukemia; Luminescent Measurements; Lymphoma, Large B-Cell, Diffuse; Monocytes; Tetradecanoylphorbol Acetate; Time Factors; Tretinoin; Tumor Cells, Cultured; Zymosan

The activation of the cAMP signaling pathway by vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating peptide (PACAP) and related peptides was studied (i) in normal peripheral human monocytes and THP-1 leukemic human monocytes, (ii) in their derived macrophage counterparts respectively obtained after spontaneous differentiation or retinoic acid (RA) treatment, and (iii) in human bronchoalveolar macrophages. In THP-1 monocytes, PACAP increased basal adenylate cyclase activity 5.3-fold, with an affinity 50-times greater than that of VIP or helodermin (Ka = 3.2 x 10(-11) M VIP), whereas in normal peripheral monocytes, PACAP and VIP exhibited similar affinities and only increased cAMP generation 2-fold (EC50 = 10(-9) M). Spontaneous and RA-induced differentiation into normal and leukemic macrophages induced a progressive loss of cAMP production and regulation of superoxide anion production by VIP and related peptides. The neoplastic transformation in THP-1 monocytes and the deficiencies in the cAMP cascade observed during the terminal differentiation of normal and leukemic human macrophages may relate to a differential genetic expression of the VIP/PACAP receptor subtypes, and alterations in the functional activity of the stimulatory and inhibitory Gs/Gi subunits of adenylate cyclase.

Topics: Adenylyl Cyclases; Cell Differentiation; Cell Transformation, Neoplastic; Colforsin; Cyclic AMP; Enzyme Activation; Humans; Hydrogen Peroxide; Isoproterenol; Leukemia; Macrophages; Monocytes; Neuropeptides; Pituitary Adenylate Cyclase-Activating Polypeptide; Pulmonary Alveoli; Signal Transduction; Superoxides; Tretinoin; Tumor Cells, Cultured; Vasoactive Intestinal Peptide

Human leukemic HL-60 cells are differentiated into granulocytic cells by retinoic acid, and this differentiation is preceded by the induction of an ecto-enzyme of NAD glycohydrolase (NADase). The NADase specifically induced by retinoic acid appeared to be encoded by human leukocyte cell surface antigen CD38 as follows. 1) There was an early expression of CD38 mRNA, together with the induction of the NADase activity, in the retinoic acid-treated HL-60 cells. 2) The time course of the expression of CD38 antigen on the cell surface was well correlated with that of the induction of NADase activity. 3) The NADase activity solubilized from the differentiated HL-60 cell membrane could be immunoprecipitated with an anti-CD38 monoclonal antibody. 4) Introduction of the CD38 cDNA into Escherichia coli cells resulted in the expression of an NADase, the activity of which was inhibited by dithiothreitol. The NADase activity in the differentiated cells was also inhibited by the reducing reagent. These results clearly indicated that the dithiothreitol-sensitive NADase activity induced by retinoic acid in HL-60 cells is attributed to the molecule of human leukocyte cell surface antigen CD38, which contains cysteine-rich cytoplasmic domain within its molecule.

Topics: ADP-ribosyl Cyclase; ADP-ribosyl Cyclase 1; Antigens, CD; Antigens, Differentiation; Base Sequence; Cell Differentiation; Dithiothreitol; DNA; Enzyme Induction; Humans; Leukemia; Membrane Glycoproteins; Molecular Sequence Data; NAD+ Nucleosidase; Polymerase Chain Reaction; Precipitin Tests; Tretinoin; Tumor Cells, Cultured

Topics: Antigens, CD; Antigens, CD34; Cyclosporine; Drug Resistance; Humans; Ketoconazole; Leukemia; Tretinoin

In human neutrophils, the synthetic lipopeptide, N-palmitoyl-S-[2,3- bis(palmitoyloxy-(2RS)-propyl]-(R)-cysteinyl-(S)-seryl-(S)-lysyl-( S)-lysyl-(S) -lysyl-(S)-lysine [Pam3CysSer(Lys)4], activates NADPH-oxidase catalyzed superoxide (O2-) formation through pertussis-toxin-sensitive and pertussis-toxin-insensitive mechanisms (Seifert, R., Schultz, G., Richter-Freund, M., Metzger, J., Wiesmüller, K.-H., Jung, G., Bessler, W. G. & Hauschildt, S. (1990) Biochem. J. 267, 795-802). We studied the effects of lipopeptides on differentiation of HL-60 leukemic cells. Pam3CysSer(Lys)4 enhanced phorbol-12-myristate-13-acetate-induced O2- formation (presumably through the expression of components of NADPH oxidase) in a concentration-dependent manner with a half-maximal effect at 100 ng/ml and a maximum at 1 microgram/ml. The effect of the lipopeptide was evident after 24 h and reached a plateau after 48 h. (2S,6S)-2-Palmitoylamino-6,7- bis(palmitoyloxy)heptanoyl-(S)-seryl-(S)-lysyl-(S)-lysyl-(S) -lysyl-(S)-lysine enhanced O2- formation as well. The effects of Pam3CysSer(Lys)4 were potentiated by dibutyryl cAMP, dimethyl sulfoxide, retinoic acid, 1,25-dihydroxyvitamin D3, interferon-gamma and tumor-necrosis-factor-alpha. Pertussis toxin, but not its B-oligomer, partially inhibited enhanced O2- formation induced by Pam3CysSer(Lys)4. O2- formation induced by arachidonic acid and gamma-hexachlorocyclohexane were more sensitive to inhibition by pertussis toxin than O2- formation induced by phorbol 12-myristate 13-acetate. Enhanced O2- formation induced by dibutyryl cAMP was not affected by pertussis toxin. Unlike ATP, histamine, prostaglandin E1 and the beta-adrenergic agonist, isoproterenol, Pam3CysSer(Lys)4 did not increase cytosolic Ca2+ [( Ca2+]i) in undifferentiated HL-60 cells. Histamine but not lipopeptides stimulated high-affinity GTPase of guanine-nucleotide-binding proteins in membranes of undifferentiated HL-60 cells. In Pam3CysSer(Lys)4-differentiated HL-60 cells, the responsiveness to the [Ca2+]i-increasing agonists, N-formyl-L-methionyl-L-leucyl-L-phenylalanine, C5a and leukotriene B4, was increased, whilst the responsiveness to prostaglandin E1 and isoproterenol was decreased. Pam3CysSer(Lys)4 did not inhibit proliferation of HL-60 cells but decreased transferrin receptor expression and increased C3bi receptor expression. Pertussis toxin did not affect proliferation and expression of transferrin and C3bi receptors. Dibutyryl cAMP was considerably more effecti

Topics: Bucladesine; Calcitriol; Cell Differentiation; Dimethyl Sulfoxide; Flow Cytometry; GTP Phosphohydrolases; Humans; Interferon-gamma; Leukemia; Lipoproteins; Pertussis Toxin; Superoxides; Transferrin; Tretinoin; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha; Virulence Factors, Bordetella

The complex and diverse biological effects of retinoic acid (RA) are mediated through specific receptors that are members of the steroid hormone family of nuclear transcription factors. The RA receptor family consists of multiple structurally distinct RA receptors, which diverge primarily at the NH2-terminal domain. The evolutionary conservation of this divergent region in individual RA receptors among different species together with their tissue-specific patterns of expression suggest that the biological function and activity of the individual RA receptors may be confined to specific tissues. To test this hypothesis in hematopoietic cells, we used retrovirus-mediated gene transduction to introduce the RA receptors RAR-alpha, RAR-beta, and RAR-gamma as well as RXR-alpha into a mutant subclone of the HL-60 promyelocytic leukemia cell line (designated HL-60R) that is relatively resistant to RA-induced granulocytic differentiation. We found that each of these structurally distinct RA receptors could restore sensitivity of the HL-60R cells to RA. A critical threshold number of transduced receptors per cell appears to be necessary to restore this functional activity. Thus, the capability to mediate granulocytic differentiation of HL-60 cells is shared among distinctly different RA receptors.

Topics: Carrier Proteins; Cell Differentiation; Cloning, Molecular; Gene Expression; Granulocytes; Humans; Leukemia; Models, Biological; Receptors, Retinoic Acid; Retroviridae; Transduction, Genetic; Tretinoin; Tumor Cells, Cultured

To evaluate the involvement of protein phosphatases (PP) in differentiation of human myelogenous leukemia HL-60 cells, we made use of potent inhibitors of PP1 and PP2A, calyculin-A (CAL-A) and okadaic acid (OKA). CAL-A and OKA could augment all-trans retinoic acid (ATRA)-induced granulocytic differentiation, whereas the differentiation toward macrophage lineage by 12-o-tetradecanoylphorbol acetate (TPA) was unchanged in the presence of CAL-A. CAL-A augmented the phosphorylation of 18K, 23K and 30K proteins induced by ATRA. The PP1 and PP2A were identified and were present mainly in the cytosol of HL-60 cells. These results suggest that either PP1 or PP2A or both may be involved in regulating granulocytic differentiation of HL-60 cells.

Topics: Cell Adhesion; Cell Differentiation; Chromatography, Agarose; Ethers, Cyclic; Granulocytes; Humans; Leukemia; Macrophages; Marine Toxins; Okadaic Acid; Oxazoles; Phosphoprotein Phosphatases; Phosphorylation; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured

The expression of the human serglycin gene was determined in nine human leukemic cell lines, representing a spectrum of erythrocytic, megakaryocytic, monocytic, granulocytic, and lymphocytic potentialities. By Northern blot analysis, a 1.4 kb transcript was characterized in some of these cell lines, using a cDNA probe coding for human serglycin. Five of these cell lines, HEL, U-937, HL-60, K-562, and KU-812 were treated with phorbol myristic acetate to induce differentiation. Under these conditions the expression of the serglycin gene was modulated compared to the non-induced cells. HL-60, K-562, and KU-812 were also induced with dimethyl sulfoxide and retinoic acid; variations in serglycin transcript level were also observed. The present investigation establishes, at the nucleic acid level, the ability of various cells mimicking different stages in the developmental pathways of the haemopoietic lineage to synthesize proteoglycans belonging to the serglycin family. The results reported here led us to conclude that serglycin expression is closely associated with the haemopoietic cell differentiation pathway. The putative functions of serglycin in the haemopoietic system are briefly discussed.

Topics: Blotting, Northern; Dimethyl Sulfoxide; Gene Expression; Humans; In Vitro Techniques; Leukemia; Proteoglycans; RNA, Messenger; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured; Vesicular Transport Proteins

We have previously shown that pretreatment of mouse erythroleukemia (MEL) cells with the fluorinated pyrimidines 5-fluorouracil (FUra) or 5-fluorodeoxyuridine (FUdR) followed by the differentiation inducer hexamethylene bisacetamide (HMBA) greatly enhanced the magnitude of their differentiation and caused extensive cell death. We have now extended these studies to address the mechanism that may be responsible for this enhancement and have also examined a human leukemic cell line (HL-60) for its sensitivity to this combination cytotoxic-differentiation therapy. We found that in HL-60 cells, pretreatment with FUdR, but not FUra, followed by 1.2% dimethylsulfoxide (DMSO) led to an 8 to 10-fold enhancement of cell death as compared to FUdR alone. When all-trans-retinoic acid (ATRA) was used instead of DMSO, the enhancement of differentiation and cytotoxicity was 5-fold. The percent of cells induced to differentiate was dependent on the concentration of both FUdR and ATRA. In HL-60 cells resistant to ATRA-induced differentiation, the combination of FUdR and ATRA did not result in enhanced cytotoxicity. Leucovorin (LV), a compound known to enhance the inhibitory effect of FUra or FUdR on DNA synthesis, increased the effectiveness of the cytotoxic-differentiation therapy, whereas thymidine inhibited its effectiveness. This suggests that inhibition of DNA metabolism may be an integral part of the differentiation-enhancing cytotoxic mechanism. To further explore inhibition of DNA synthesis, DNA was extracted under alkaline or neutral conditions from 3H-thymidine-labelled cells that were treated with FUra/LV and HMBA individually or in combination. The emergence of single and double-strand DNA breaks was monitored by agarose gel electrophoresis. In parallel to the enhancement of cytotoxicity, the combination treatment (FUra/LV followed by HMBA) also produced a 2.5-3-fold increase in the DNA breaks when compared to the same effect obtained by the agents applied individually. Thus, we propose that DNA degradation may be the mechanism responsible for the enhanced loss of cell viability. In summary, we report here an approach which is targeted to increasing the death rate of leukemic cells through the combined use of low doses of cytotoxic drugs and differentiation inducers.

Topics: Cell Differentiation; Cell Line, Transformed; Dimethyl Sulfoxide; Drug Therapy, Combination; Floxuridine; Fluorouracil; Humans; Leukemia; Pyrimidines; Tretinoin; Tumor Cells, Cultured

Two calcium binding proteins, MRP-8 and MRP-14, are specifically synthesized in human myeloid cells. This paper shows that Me2SO, all-trans-retinoic acid (RA) and 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3), but not 12-O-tetradecanoyl phorbol-13-acetate (PMA) are potent inducers of MRP-8/14 protein complex in human leukemic cells. Transforming growth factor-beta 1 (TGF-beta 1) is shown to enhance the inductive effect of RA and 1 alpha,25(OH)2D3. We have examined the possibility that MRP expression is regulated through the protein kinase pathway. Both cytosolic and membrane-bound protein kinase C (PKC) activities increased during differentiation by RA and 1 alpha,25(OH)2D3. PMA-treatment led to a decrease of cytosolic PKC activity and an increase of membrane-bound PKC activity in the presence of these differentiation inducers, while PMA alone resulted in low cytosolic and high membrane-bound PKC activities. PKC inhibitor H7 inhibited MRP synthesis in HL-60 cells treated with RA and 1 alpha,25(OH)2D3. These results suggest that cytosolic PKC activity may be involved in a stimulatory pathway of MRP synthesis and that protein phosphorylation reactions may play important roles in MRP expression during myelocytic differentiation.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Blotting, Northern; Calcitriol; Calcium-Binding Proteins; Calgranulin A; Calgranulin B; Cell Differentiation; Cytosol; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Humans; Isoquinolines; Leukemia; Mice; Mice, Inbred BALB C; Piperazines; Protein Kinase C; RNA, Messenger; Tetradecanoylphorbol Acetate; Transforming Growth Factor beta; Tretinoin; Tumor Cells, Cultured

To elucidate the differentiation-associated expression of enzymes catalyzing arachidonic acid metabolism, we measured arachidonate metabolites by reverse-phase high pressure liquid chromatography in monocytoid leukemia (ML-1, THP-1, and U937) and myeloid leukemia (KG-1) cell lines. Undifferentiated ML-1 or THP-1 cells produced trace amounts of eicosanoids via the cyclooxygenase (COX) and lipoxygenase (LOX) pathways. Upon differentiation induced by phorbol ester (phorbol 12-myristate 13-acetate [PMA]), metabolites via the COX pathway were increased by 100-fold in ML-1 and THP-1 cells, while the LOX products remained barely detectable. All the COX metabolites were elevated, but thromboxane A2 (TXA2) formation was threefold higher in ML-1 cells than in THP-1 cells. Similar time-related increases in COX metabolites were observed in THP-1 cells induced to differentiate with retinoic acid. Undifferentiated U937 cells were capable of generating a much higher quantity of COX products than ML-1 or THP-1 cells, but, upon PMA-induced differentiation, COX products were increased by only two-fold to threefold over the undifferentiated cells and the total COX products in differentiated U937 cells were only one-seventh of those produced by differentiated ML-1 or THP-1 cells. KG-1 cells had an entirely different metabolic profile. They produced a large quantity of a metabolite coeluted with prostaglandin D2, and PMA had no effect on inducing changes in arachidonic acid (AA) metabolism. Increased COX metabolite formation in differentiated THP-1 and ML-1 cells was due to an enhanced level of prostaglandin H synthase enzyme mass, as measured by Western blot analysis. The TXA synthase activity was also increased by approximately 100-fold in PMA-induced ML-1 cells and 10-fold in THP-1 cells. These findings indicate that increased expression of prostaglandin H and TXA synthase enzymes is a feature of differentiated monocytoid leukemia cell lines.

Topics: Arachidonic Acid; Calcimycin; Cell Differentiation; Granulocytes; Humans; Leukemia; Lipoxygenase; Monocytes; Prostaglandin-Endoperoxide Synthases; Tetradecanoylphorbol Acetate; Thromboxane-A Synthase; Tretinoin; Tumor Cells, Cultured

Retinoic acid, a derivative of vitamin A, is shown to inhibit the levels of inositol phosphates and diacylglycerol by 25-30% when added to intact HL-60 cells at concentrations which induce differentiation. The onset of inhibition occurs after 10 min and reaches a maximum at 45 min. To study the mechanism and the site of action of retinoic acid, the activity of the phosphatidylinositol bisphosphate-specific phospholipase C was studied in cells permeabilized with streptolysin O and in membrane preparations. Phospholipase C activity was stimulated either via the guanine nucleotide regulatory protein (G-protein) or directly by Ca2+. Retinoic acid treatment, in a time- and concentration-dependent manner, led to a decrease in phospholipase C activity when stimulated with either GTP gamma S or NaF, both of which activate the enzyme via the G-protein. By contrast, it had no effect on the enzyme activity when stimulated with Ca2+ alone. This indicates that retinoic acid interferes with the coupling of the G-protein and phospholipase C. A relationship between the inhibition of phospholipase C activity and the induction of differentiation by retinoic acid was investigated. Only a small inhibition of GTP gamma S-stimulated phospholipase C activity was observed when an analogue of retinoic acid, etretine or Ro10-1670, with low differentiating activity, was used. Moreover, no inhibition of the GTP gamma S-stimulated phospholipase C activity was observed in an HL-60 sub-line resistant to retinoic acid. These results suggest that phospholipase C inhibition is an important step in the induction of differentiation.

Topics: Bacterial Proteins; Calcium; Cell Differentiation; Cell Membrane Permeability; Diglycerides; GTP-Binding Proteins; Humans; Inositol Phosphates; Kinetics; Leukemia; Protein Kinase C; Streptolysins; Tretinoin; Tumor Cells, Cultured; Type C Phospholipases

In HL60 cells a nuclear protein of Mr 55,000 is retinoylated, with the formation of a thioester bond. To gain further knowledge on the role of retinoylation we studied it in cell lines with varied responses to retinoic acid (RA). Compared to HL60 the extent of retinoylation (mol/cell) was about fivefold higher in HL60/MRI, a mutant which is more sensitive to RA than HL60. Retinoylation occurred to the same extent and at similar rates in HL60 and in HL60/RA-res, a mutant resistant to differentiation by RA. One-dimensional polyacrylamide gel electrophoresis patterns for the three HL60 cell lines were similar. However, two-dimensional polyacrylamide gel electrophoresis patterns of the three HL60 cell lines were distinct. While we saw the same major retinoylated protein of Mr 55,000 in the three cell lines, the HL60/RA-res cells also contained a high level of a protein with the same Mr and a lower pI. The extent of retinoylation was greater in the RA-sensitive embryonal carcinoma cell line, PCC4.aza1R, than in a RA-resistant cell line, PCC4.(RA)-2. One-dimensional polyacrylamide gel electrophoresis patterns of retinoylated proteins of the embryonal carcinoma cell lines were different from HL60 and from each other. The retinoylation pattern of the normal canine kidney cell line (MDCK) was different from either HL60 or the embryonal carcinoma cells. These results showed the retinoylation was widespread and that the response to RA of different cell types may depend on the retinoylation of specific proteins.

Topics: Cell Line; Cell Transformation, Neoplastic; Drug Resistance; Electrophoresis, Gel, Two-Dimensional; Humans; Kidney; Leukemia; Molecular Weight; Mutation; Neoplasm Proteins; Nuclear Proteins; Teratoma; Tretinoin; Tumor Cells, Cultured

Non-induced HL-60 cells (N-IND) and HL-60 cells induced to differentiate with 2 microM retinoic acid (IND) were electropermeabilized with electrical discharges, and the intracellular Ca2+ stores were measured in each type of cell. Both N-IND and IND cells accumulate Ca2+ in the presence of ATP after electropermeabilization. The Ca2+ is stored in at least two different compartments; accumulation in one of the compartments is inhibited by oligomycin and CCCP, and it is not releasable by Ins(1,4,5)P3. The maximal accumulation of Ca2+ by the Ins(1,4,5)P3 sensitive pool is about 0.3 nmol/10(6) cells and 0.9 nmol/10(6) cells for the N-IND and for the IND cells, respectively, and the half-maximal value occurs at a free Ca2+ concentration of 0.23 microM and 0.63 microM, respectively. The oligomycin + CCCP sensitive pool hardly accumulates any Ca2+ at this level of free Ca2+, but at higher free [Ca2+] (greater than microM) its maximal capacity is 80-100-fold higher than the Ins(1,4,5)P3-sensitive pool (about 17-18 nmol/10(6) cells). It is concluded that at physiological free Ca2+ concentrations, the non-mitochondrial Ca2+ pool is regulating the intracellular free Ca2+ in N-IND and IND HL-60 cells, and that this Ca2+ pool can be mobilized by Ins(1,4,5)P3. Furthermore, the capacity of this pool increases about 3-fold when the cells are induced to differentiate with retinoic acid.

Topics: Adenosine Triphosphate; Calcium; Cell Differentiation; Cell Membrane Permeability; Electric Stimulation; Humans; Inositol 1,4,5-Trisphosphate; Kinetics; Leukemia; Organelles; Tretinoin; Tumor Cells, Cultured; Vanadates

HL-60 leukemic cells were differentiated along the neutrophilic pathway with retinoic acid (RA) or along the monocytic pathway with 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). Using a high-resolution two-dimensional electrophoresis technique and subsequent silver staining, differentiation-dependent changes in cytosolic protein pattern of HL-60 cells were analysed and were compared with the cytosolic protein pattern of human neutrophils. The amount of 64 and 50 out of a total of 632 proteins studied was increased or decreased in RA- and 1,25(OH)2D3-differentiated HL-60 cells, respectively, in comparison to undifferentiated HL-60 cells. Thirty-three of these proteins were similarly altered in RA- and 1,25(OH)2D3-differentiated HL-60 cells. Twenty-two and 25 of the proteins altered in amount in RA- or 1,25(OH)2D3-differentiated HL-60 cells versus undifferentiated HL-60 cells were similarly altered in human neutrophils in comparison to undifferentiated HL-60 cells. Seven and 10 of the proteins altered in amount in RA- or 1,25(OH)2D3-differentiated HL-60 cells had specific equivalents in neutrophil cytosol. Our results show (i) that neutrophilic and monocytic differentiation is associated with decreases and increases in amount of cytosolic proteins; (ii) that both differentiation processes share a common set of alterations; and (iii) are associated with specific alterations in protein amount.

Topics: Calcitriol; Cell Differentiation; Cytosol; Electrophoresis, Gel, Two-Dimensional; Humans; Leukemia; Neutrophils; Proteins; Silver; Staining and Labeling; Tretinoin; Tumor Cells, Cultured

The expression of c-myc and two calcium-binding proteins, MRP8 and MRP14, has been analyzed in wild-type and differentiation-resistant HL-60 variants. In HL-R5 cells, resistant to the induction of differentiation by retinoic acid but not DMSO, the characteristic c-myc down-regulation which is associated with HL-60 differentiation, as well as increased levels of MRP8 and MRP14, is detectable only after DMSO treatment. By contrast HL-D4 cells, which were selected for resistance to the induction of differentiation by DMSO alone, are actually resistant to both DMSO and retinoic acid. However, treatment of HL-D4 cells with DMSO results in a transient c-myc down-regulation in the absence of either growth arrest or induction of differentiation. Neither agent can induce an increase in the level of either MRP8 or MRP14 in HL-D4. The resistance of HL-D4 cells to DMSO and retinoic acid, and the different effects of these agents on c-myc RNA levels, despite their common effect on the expression of MRP8 and MRP14, suggest that the two agents act through different pathways which coverage before the onset of myeloid differentiation in HL-60 cells.

Topics: Cell Differentiation; Dimethyl Sulfoxide; Humans; Leukemia; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-myc; RNA, Messenger; RNA, Neoplasm; Tretinoin; Tumor Cells, Cultured

To determine the activity of fenretinide in patients with myelodysplastic syndromes, 15 patients were treated (300 mg/d starting dose, escalated to 400 mg/d) for a 12-week course. No responses were observed in 14 evaluable patients. Exacerbation of thrombocytopenia occurred in one patient with chronic myelomonocytic leukemia, who succumbed to an intracerebral hemorrhage after 3 weeks of treatment. Two patients with long-standing stable sideroblastic anemia experienced interval leukemic progression. In one patient, clinical features of chronic myelomonocytic leukemia appeared, characterized by a striking rise in peripheral monocyte count (0.49 x 10(9)/l to 10.8 x 10(9)/l) and hepatosplenomegaly, which resolved promptly after cessation of treatment. The second patient experienced evolution into acute myelomonocytic leukemia with cytogenetic progression. The drug was well tolerated with no patient having to discontinue treatment because of toxicity. We conclude that fenretinide lacks clinical efficacy in the treatment of myelodysplasia and in some patients may enhance leukemic progression.

Topics: Acute Disease; Aged; Cerebral Hemorrhage; Drug Evaluation; Fenretinide; Humans; Leukemia; Leukocytosis; Male; Middle Aged; Monocytes; Myelodysplastic Syndromes; Thrombocytopenia; Tretinoin

The expression of the newly described human retinoic acid receptor alpha (RAR alpha) in six nonlymphoid and six lymphoid leukemia cell lines and nine freshly obtained samples of leukemia cells from patients with acute nonlymphoid leukemia was assessed by Northern blot analysis, using a full length cDNA clone of RAR alpha as probe. RAR alpha was expressed in all 12 cell lines and in all fresh leukemia samples as two major transcripts of 2.6 and 3.5 kb in size. Levels of RAR alpha expression and transcript sizes in retinoid-sensitive cells (such as HL60 or fresh promyelocytic leukemia cells) were not different from those in other samples. Moreover, expression of RAR alpha was not significantly modulated by exposure to cis-retinoic acid (cisRA) in either cisRA-responsive or unresponsive cells. By using a 3' fragment of the RAR alpha gene as a probe, we confirmed that the transcripts visualized did not represent the homologous RAR beta gene. RAR alpha appears to be expressed in most human leukemia cells regardless of the type of biologic response to retinoic acid.

Topics: Blotting, Northern; Carrier Proteins; Cell Differentiation; Chromosomes, Human, Pair 17; DNA-Binding Proteins; Gene Expression Regulation; Humans; Leukemia; Receptors, Retinoic Acid; RNA, Messenger; RNA, Neoplasm; Tretinoin; Tumor Cells, Cultured

Retinoic acid receptor (RAR)-alpha mRNA expression was studied in a variety of myeloid leukemia cells with variable responsiveness to the induction of terminal differentiation by retinoic acid (RA). Cells from both the wild-type (wt), RA-responsive HL-60 promyelocytic leukemia cell line and a selected greater than or equal to 300-fold RA-resistant subline expressed approximately equal amounts of two RAR-alpha transcripts, 4.0 and 3.1 kb in size. In wt cells, the RAR-alpha did not change during induction of granulocyte differentiation by RA or macrophagic differentiation by 12-0-tetradecanoylphorbol-13-acetate (TPA). Relative to HL-60 cells, other cultured and fresh myeloid leukemia cells expressed 2.5-fold less to equal amounts of the RAR-alpha transcripts. The relative expression in six cases of acute promyelocytic leukemia (APL; two RA-responsive; one, previously treated with 13-cis-RA in vivo, equivocally RA-responsive) and one case of acute myelogenous leukemia (AML) with promyelocytosis (RA unresponsive) was 0.91 +/- 0.14 versus 0.53 +/- 0.14 for eight cases of nonpromyelocytic AML (p congruent to 0.001). Lymphoid leukemia cells expressed 2- to 5-fold less RAR-alpha mRNA. No qualitative variations in the mRNA transcripts were observed, although the 3.1 kb transcript was relatively decreased in three cases. The RAR-alpha gene was not amplified or detectably rearranged in any DNA source, although an apparent EcoRI restriction fragment length polymorphism was observed. It is concluded (a) that the steady-state level of RAR-alpha mRNA is not tightly correlated with natural responsiveness/unresponsiveness or, in some instances, acquired resistance to RA-induced differentiation and (b) that further studies are needed to determine if the mean 1.7-fold higher RAR-alpha mRNA level in APL cells could be an essential factor in the RA-responsiveness of APL cells, as primarily regulated at a different molecular level.

Topics: Adult; Aged; Carrier Proteins; Chromosome Aberrations; DNA, Neoplasm; Female; Gene Expression; Humans; Leukemia; Male; Middle Aged; Receptors, Retinoic Acid; RNA, Messenger; Tretinoin; Tumor Cells, Cultured

Some of the current critical issues in the tiazofurin treatment of end-stage leukemia were presented and discussed. 1. Tiazofurin infusions (daily X 10 to 15) provided remissions in 50% of end-stage leukemic patients. The remissions, of 1 to 10 months' duration, varied from antileukemic effect or hematologic improvement to complete response and complete remission. The total survival of the responding patients was from about 1 to 15 months. 2. Our administration of tiazofurin in a 60-min infusion by pump decreased the incidence and severity of toxicity. 3. It was shown that tiazofurin dose does not need to be escalated at each relapse. Depending on the biochemical and hematological response in this novel protocol, 2,200 to 4,400 mg/m2 tiazofurin appeared to be sufficient to provide remissions. 4. A new role was identified for allopurinol, originally given to decrease uric acid in the plasma. Allopurinol markedly increased plasma hypoxanthine concentrations which competitively inhibited the activity of the salvage enzyme, guanine phosphoribosyltransferase, in the blast cells. Thus, the elevated hypoxanthine plasma levels inhibited guanine salvage. To maintain high hypoxanthine levels allopurinol (100 mg) was given every 4 to 6 hr. This provided combination chemotherapy with tiazofurin which inhibited IMP dehydrogenase activity and blocked the de novo biosynthesis of guanylates in the blast cells. 5. Preliminary evidence was obtained in the patients that tiazofurin induced differentiation of the bone marrow. Recent studies also showed that tiazofurin down-regulated the expression of the c-Ki-ras oncogene in K562 erythroleukemic cells. Therefore, tiazofurin treatment provides an impact by chemotherapy, induced differentiation, and, if applicable, through down-regulation of the ras oncogene. 6. Novel aspects of tiazofurin treatment include rational targeting and a continuously monitored trial by measurement of the activity of IMP dehydrogenase and of GTP and TAD concentrations in blast cells and of tiazofurin and hypoxanthine in plasma. 7. Since tiazofurin has not yet achieved lasting remissions in patients nor terminal differentiation of leukemic cells it probably will be advantageous to combine tiazofurin with other drugs to provide synergism. In preclinical tissue culture studies in HL-60 cells synergy was observed with retinoic acid. This may be of interest because retinoic acid also caused differentiation and down-regulation of the myc oncogene.

Topics: Adult; Aged; Aged, 80 and over; Allopurinol; Animals; Antimetabolites, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Cell Differentiation; Down-Regulation; Drug Interactions; Female; Genes, ras; Guanine; Humans; Hypoxanthine; Hypoxanthines; Leukemia; Liver Neoplasms, Experimental; Male; Middle Aged; Ribavirin; Ribonucleosides; Tretinoin; Tumor Cells, Cultured; Uric Acid

Three cell populations with different DNA indices were demonstrated in a case of biphenotypic terminal transferase (TdT)/myeloid-positive acute leukemia which had developed from a pre-leukemic diploid population also expressing biphenotypic features. At the time of development of acute leukemia, flow-cytometric analysis revealed expression of TdT by the diploid, the tetraploid, and the near-triploid cells, but only the tetraploid cells carried the myeloid-specific M2 antigen. Cytogenetic analysis showed four stemlines, diploid, tetraploid, tetraploid with del(2), and near-triploid with del(2) and variable chromosome losses. In vitro treatment with retinoic acid induced the expression of the M2 antigen by the diploid cells as well. This in vitro result is consistent with a myeloid differentiation commitment of the pluripotent leukemic stem cell.

Topics: Acute Disease; Aged; Antigens, Neoplasm; DNA, Neoplasm; Female; Hematopoietic Stem Cells; Humans; Leukemia; Neoplastic Stem Cells; Phenotype; Ploidies; Tretinoin

A number of cloned biologic factors are currently available that are candidates for therapy of myelodysplastic syndromes and, by extension, acute nonlymphoblastic leukemia. gamma-Interferon and, to a greater extent, tumor necrosis factor exhibit leukemic differentiative effects without the potential for stimulation of leukemic clones. These effects may be enhanced by combinations of these with one another or with chemical inducers of differentiation such as retinoic acid or vitamin D derivatives. The colony-stimulating factors clearly have potent in vivo effects upon hematopoiesis. The lineage specific factors (G- or M-CSF) may have greater differentiation induction potential and less risk of accelerating emergence of leukemic clones than the earlier acting factors (GM- or multi-CSF). Thus, several potentially fruitful avenues for clinical research are currently available.

Topics: Cloning, Molecular; Colony-Stimulating Factors; Granulocyte Colony-Stimulating Factor; Granulocyte-Macrophage Colony-Stimulating Factor; Growth Substances; Humans; Interferons; Interleukin-3; Leukemia; Lymphokines; Myelodysplastic Syndromes; Tretinoin; Tumor Necrosis Factor-alpha; Vitamin D

62 evaluable patients with myelodysplastic syndromes (MDS) or acute leukemia were treated with different combinations of low dose ara-C, alpha-interferon (IFN), 1 alpha-hydroxyvitamin D3 (vit D3) and retinoic acid. The aim was to study the efficacy and toxicity of each combination. The overall rate was 44%. Of these, 50% responded favorably to the combination of IFN, vit D3 and retinoic acid (IDR), which was comparable to the response rate of 43% for low-dose ara-C. The results of the IDR treatment may be explained by additive or synergistic effects between the separate drugs in the combination. Ara-C and IDR treatment was generally well-tolerated but interferon gave more side effects than any other drug used in the study. Evaluation of the full combination of ara-C, IFN, vit D3 and retinoic acid was not possible because of toxicity. Marrow hypoplasia was infrequent (5/27 patients) in cases responding favorably to treatment. Complete remissions were not longer than partial remissions or significant responses.

Topics: Actuarial Analysis; Acute Disease; Adolescent; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Cytarabine; Drug Administration Schedule; Female; Humans; Hydroxycholecalciferols; Interferon Type I; Leukemia; Male; Middle Aged; Myelodysplastic Syndromes; Remission Induction; Tretinoin

The capacity of retinoic acid (RA) and vitamin D to induce differentiation of HL-60 cells in an agar gel system that permits a high cloning efficiency was studied in the presence or absence of leukocyte-conditioned medium (LCM). Vitamin D was about 10 times more effective in inducing differentiation than RA. LCM significantly increased the differentiation-inductive capacity of both vitamins, although LCM did not have an effect of its own. During the first days of culture, the number of cells per clone increased with either vitamin or LCM alone as compared to control cultures. This suggests that cellular proliferation may be important in the initial phase of the differentiation induction. No synergy in this respect was found between RA and vitamin D in the presence or absence of LCM. Thus it is doubtful whether RA and vitamin D have a true synergistic effect on individual HL-60 cell differentiation as previously described in liquid cultures. Furthermore, the findings suggest that the process of differentiation induction regarding the growing cells in agar gel involves an all-or-none process. The data may also help elucide the observed relationship between the in vitro production of colony stimulating activity and favorable prognosis of AML.

Topics: Cell Differentiation; Cell Division; Cell Line; Clone Cells; Colony-Forming Units Assay; Culture Media; Humans; Leukemia; Lymphocytes; Tretinoin; Vitamin D

Topics: Cell Differentiation; Cell Line; Culture Media; Humans; Leukemia; Leukemia, Experimental; Leukemia, Myeloid, Acute; Lymphocytes; Phytohemagglutinins; Tretinoin

Serum transferrin (the iron binding protein) exerts its iron carrier function at the cell surface after binding to the appropriate receptor (TrR). In this work it is demonstrated that differentiating agents induce loss of TrR from the surface of three leukemic cell lines (Molt-3, HL-60 and K-562). Loss of TrR correlates with change in morphology and induction of phenotypic markers of the differentiated cells. Removal of the differentiating agent from the culture is followed by reexpression of TrR on the cell surface. The data presented in this paper suggest that TrR may play a regulatory role in cell differentiation and malignant transformation.

Topics: Butyrates; Butyric Acid; Cell Differentiation; Cell Line; Dimethyl Sulfoxide; DNA Replication; Heme; Humans; Leukemia; Leukemia, Lymphoid; Leukemia, Myeloid; Leukemia, Myeloid, Acute; Receptors, Cell Surface; Receptors, Transferrin; Tetradecanoylphorbol Acetate; Transferrin; Tretinoin

We have previously demonstrated that declines in c-myc expression precede the induction of c-fos and c-fms transcripts during monocytic differentiation of human leukemia (HL-60 and U-937) cell lines. The present study has monitored the effects of 1-beta-D-arabinofuranosylcytosine (ara-C) on proto-oncogene expression in U-937 cells. The results demonstrate that ara-C inhibits both U-937 proliferation and c-myc expression in a concentration- and time-dependent manner. At non-toxic concentrations of ara-C, these decreases in c-myc RNA occur in the absence of changes in the level of actin transcripts. The results also demonstrate that ara-C increases c-fos but not c-fms expression. Similar findings have been obtained with retinoic acid. Furthermore, although both agents induce a more mature U-937 phenotype, ara-C is a relatively weak inducer of these cells. These findings would suggest that the changes in proto-oncogene expression induced by ara-C may be related to induction of differentiation or the inhibitory effects of this agent on proliferation.

Topics: Actins; Cell Division; Cell Line; Cytarabine; Humans; Leukemia; Proto-Oncogene Mas; Proto-Oncogene Proteins; Proto-Oncogenes; Transcription, Genetic; Tretinoin

Untreated and retinoic acid (RA) treated human leukemia-lymphoma cell lines reflecting hematopoietic cells at various stages of differentiation, were examined electron microscopically for their surface negative charge distribution using cationized ferritin (CF), an electron dense label of anionic sites. The results indicate that there is a correlation between the CF labeling density/distribution and the stage of lymphoid cell differentiation. Viable unfixed null cell lines show a low CF labeling density with few and small CF patches. A gradual increase in CF labeling density and increase in size and number of CF patches correlates with the stage of differentiation on cell lines of both T or B origin. Treatment of viable unfixed cells with 10(-5) MRA for 10 days seems to prevent the CF-induced formation of CF patches, resulting in a continuous and even distribution of the CF label, similar to that observed on the surface of cells fixed before CF labeling. Some correlation between the distribution of surface anionic sites and the malignant potential of the human leukemic lines could be detected.

Topics: Anions; Cell Differentiation; Cell Line; Ferritins; Humans; Leukemia; Lymphocytes; Lymphoma; Surface Properties; Tretinoin

We have used a panel of 5 monoclonal antibodies against normal myeloid-differentiation antigens to determine retinoic acid-induced changes in cell surface antigens on ANLL bone marrow cells from 24 children at the time of diagnosis. Two of these antibodies (T5A7 and 5F1) detect antigens expressed on normal mature granulocytes and on all monocytes, respectively. The percentage of positive cells for each monoclonal antibody was determined by indirect immunofluorescence. After 5 days incubation with 1 microM RA in liquid culture, cells from 11 of 24 patients showed substantially increased expression of one or both antigens detected by T5A7 and 5F1. Leukemic bone marrow cells from these patients were also cultured in methylcellulose medium with and without 1 microM RA for one week, and cells from 16 of 24 patients showed clonal growth. Cultures from 10 of these 16 patients showed RA-induced inhibition of colony growth; of these 10 patients, cultures from six patients showed RA-induced increases in antigens associated with maturing myeloid cells. This suggests that the RA-induced inhibition of clonal growth observed with leukemic cells from these patients may be accompanied by the increased expression of maturation-associated myeloid antigens by these cells in the presence of RA.

Topics: Acute Disease; Antibodies, Monoclonal; Antigens, Surface; Bone Marrow; Cell Differentiation; Cell Survival; Child; Granulocytes; Humans; Leukemia; Methylcellulose; Tretinoin

The human promyelocytic cell lines HL-60 can be induced to undergo differentiation to either granulocyte- or macrophage-like cells. We followed the changes in the synthesis and content of ferritin in this and other cell lines during differentiation. Ferritin content of HL-60 cells ranged from 11 to 81 fg/cell, depending on the clone tested. Following exposure to dimethylsulfoxide (DMSO) or retinoic acid (RA) an increase in ferritin and a decrease in total protein synthesis was observed, resulting in increased ferritin content, reaching a peak after 2 days. This increase occurred prior to the appearance of the typical morphological and functional characteristics of mature granulocytes. A correlation was found between concentrations of DMSO effective in inducing differentiation and the increase in ferritin content. Other inducers of granulocyte differentiation had a similar effect, while 12-O-tetradecanoylphorbol-13-acetate (TPA), an inducer of macrophage differentiation, had not. Another human cell line (U-937), which was induced into monocyte-like cells by RA, showed a twofold increase in ferritin content following differentiation. Addition of iron to the culture medium increased ferritin content of both differentiating and non-differentiating cells, but the former responded to lower concentrations of iron. The increase in ferritin during differentiation, however, was not related to an accelerated iron uptake. The present results suggest that changes in the intracellular ferritin of the developing myeloid cells may play a regulating role in the process of maturation of these cells.

Topics: Cell Differentiation; Cell Line; Dimethyl Sulfoxide; Ferritins; Granulocytes; Humans; Leukemia; Macrophages; Tretinoin

The human leukemic cell lines, K562, KG-1, and HL-60, and the blast subclones, KG-1a and HL-60 blast, were utilized to relate differences in nonhistone protein antigens to stages of myeloid cell differentiation. Chromatin proteins were separated on SDS-polyacrylamide gels, transferred electrophoretically to nitrocellulose sheets, and visualized by the peroxidase-antiperoxidase method of Sternberger. Screening with antisera raised against total and dehistonized chromatin and a nuclear extract from these cells revealed quantitative as well as qualitative differences between the cell lines. A decrease in antigen content seemed to parallel progressive stages of myeloid cell development. The results indicate that a number of chromosomal protein antigens are lost or modified during differentiation. An antigen(s) of approximately 55,000 molecular weight was found in HL-60 chromatin, but was not present in its less differentiated subclone or in the other lines representative of earlier stage cells. Upon the induction of HL-60 cells to mature to end stages with 4 microM retinoic acid, a significant increase in the mol wt 55,000 activity was seen. This antigen was detected only with antisera against HL-60 total chromatin and granulocyte nuclei, and it was found only in normal mature granulocytes and in the later stage cells of the HL-60 culture. Thus, the antigen appears to be associated with a differentiated myeloid function.

Topics: Antibodies, Neoplasm; Antigens, Neoplasm; Antigens, Nuclear; Bone Marrow; Cell Line; Cell Transformation, Neoplastic; Chromatin; Chromosomal Proteins, Non-Histone; Clone Cells; Humans; Leukemia; Nucleoproteins; Tretinoin

In the present study, the expression of beta-adrenergic receptors, the activity of the enzyme adenylate cyclase (AC), and the intracellular concentration of cyclic adenosine 3',5'-monophosphate (cAMP) were investigated in HL-60 cells before and after their differentiation to monocytic or more mature granulocytic cells. Treatment of the HL-60 promyelocytes with 12-O-tetradecanoylphorbol 13-acetate or human interleukin 2 resulted in the appearance of cells with monocytic characteristics (morphology, non-specific esterase, adherence, reaction with a monocyte-specific monoclonal antibody). Induction with retinoic acid resulted in differentiation to cells with typical features of mature granulocytes (morphology, peroxidase, nitro-blue tetrazolium reduction). During maturation to monocytes, the density of beta-adrenergic receptors decreased, whereas it remained constant during maturation to granulocytes. In comparison with normal circulating monocytes or polymorphonuclear granulocytes, expression of beta-adrenergic receptors on the surface of the differentiated HL-60 cells was low. Activation of AC by the hormones isoproterenol, prostaglandin E1, and histamine generally decreased with HL-60 maturation and enzyme activities were markedly below those measured in normal peripheral leukocytes. In the induced monocytic HL-60 cells, the weak effectiveness of isoproterenol was due to the loss of beta-adrenergic receptors. In the induced granulocytic HL-60 cells, the reduced hormonal AC activation could be explained by the impaired coupling between hormone receptors and catalytic enzyme unit. The concentration of intracellular cAMP after differentiation of HL-60 cells reflected the increase in basal AC activity and the decrease in hormone stimulation of the enzyme. Our data indicate that HL-60 cells induced to differentiate possess some monocyte- and granulocyte-like properties, but do not meet several important functional criteria of their new cell identities.

Topics: Adenylyl Cyclases; Cell Differentiation; Cell Line; Cyclic AMP; Granulocytes; Humans; Leukemia; Monocytes; Receptors, Adrenergic; Receptors, Adrenergic, beta; Tetradecanoylphorbol Acetate; Tretinoin

The presence and level of cellular retinol-binding protein (CRBP) and cellular retinoic acid-binding protein (CRABP) were determined in several neoplastic cell lines. These cells exhibited different degrees of susceptibility to growth inhibition in culture by two retinoids, retinyl acetate and retinoic acid. CRABP was detected in 10 and CRBP in 3 of the 11 tested cell lines. The levels of CRBP and CRABP were in the ranges 15-3,400 and 4-1,290 pmol per 10(9) cells, respectively, as determined by sucrose gradient centrifugation. Cell lines that contained CRABP included S91 and B16 melanomas; Mm5mT and DMBA No. 8 mammary adenocarcinomas; BW5147, BW5147.RicR, and P3 neoplastic lymphoid cells; F361.2 (a hybrid cell line obtained by fusion of MSV3T3 and BW5147); MSV3T3 sarcoma; and RAW8 lymphosarcoma. All but the last two cell lines were inhibited by retinoic acid in culture. CRBP was detected in extracts of S91, Mm5mT, and RAW8. Retinyl acetate inhibited the growth of all cell lines with the exception of RAW8, MSV3T3, and F361.2. No correlation was found between the level of either binding protein and the extent of growth inhibition by either retinyl acetate or retinoic acid. Neither of the binding proteins was detected in L1210-A5 leukemia cells, whose proliferation can be inhibited by both retinyl acetate and retinoic acid. These data indicated that screening cell lines for the presence and level of CRBP and CRABP is not sufficient to predict the susceptibility of cultured cells to growth inhibition by retinoids.

Topics: Adenocarcinoma; Animals; Carrier Proteins; Cell Count; Cell Line; Leukemia; Lymphoma, Non-Hodgkin; Melanoma; Mice; Neoplasms, Experimental; Retinol-Binding Proteins; Retinol-Binding Proteins, Cellular; Sarcoma; Tretinoin