tretinoin and Burkitt-Lymphoma

Lytic Epstein-Barr virus (EBV) replication occurs in differentiated, but not undifferentiated, epithelial cells. Retinoic acid (RA) induces epithelial cell differentiation. The conversion of retinol into its active form, retinoic acid, requires retinol dehydrogenase enzymes. Here we show that AGS gastric carcinoma cells containing the lytic form of EBV infection have enhanced expression of a gene (DHRS9) encoding an enzyme that mediates conversion of retinol into RA. DHRS9 expression is also increased following induction of lytic viral infection in EBV-positive Burkitt lymphoma cells. We demonstrate that the EBV immediate-early protein, BZLF1, activates the DHRS9 promoter through a direct DNA binding mechanism. Furthermore, BZLF1 expression in AGS cells is sufficient to activate DHRS9 gene expression and increases the ability of retinol to induce the RA-responsive gene, CYP26A1. Production of RA during the lytic form of EBV infection may enhance viral replication by promoting keratinocyte differentiation.

Topics: 3-Hydroxysteroid Dehydrogenases; Alcohol Dehydrogenase; Burkitt Lymphoma; Capsid; Cell Differentiation; Cell Line, Tumor; Cytochrome P-450 Enzyme System; HeLa Cells; Herpesvirus 4, Human; Humans; Immunoglobulin G; Keratinocytes; Retinoic Acid 4-Hydroxylase; Tretinoin; Virus Activation; Virus Latency; Virus Replication; Vitamin A

We have previously demonstrated that 13-cis-retinoic acid (RA), 9-cis-RA and all-trans-RA (ATRA) powerfully inhibit the proliferation of Epstein-Barr virus-immortalized B-lymphoblastoid cell lines (LCLs). The aim of the present study was to assess whether these compounds are effective at inhibiting the growth of B cells at more advanced stages of lymphomagenesis, including fully transformed B lymphocytes. To this end, c-myc-transfected LCLs (myc-LCLs) and Burkitt's lymphoma (BL) cell lines were used. We report that 13-cis-RA, 9-cis-RA and ATRA also markedly inhibit the proliferation of myc-LCLs by inducing G(0)/G(1) growth arrest as well as enhancing rates of apoptosis. Conversely, all but 1 (DG75) of the 8 BL cell lines investigated were poorly RA-responsive. Moreover, unlike LCLs and myc-LCLs, RA-treated DG75 cells rapidly resumed proliferation upon drug removal. Analysis of cell cycle-regulatory proteins showed that, as in LCLs, strong up-regulation of p27(Kip-1) and increased levels of under-phosphorylated pRb and p130 were detected in RA-treated DG75 cells. While the catalytic activity of all 3 G(1)-associated CDKs (CDK2, CDK4 and CDK6) was strongly inhibited in RA-treated LCLs, only CDK2-associated kinase activity was reduced in DG75 cells arrested in G(0)/G(1) by RA. Moreover, RA-treated DG75 cells failed to show the down-regulation of cyclin D3 observed in LCLs. Use of receptor-selective agonists and antagonists showed that in LCLs and RA-responsive BL cells, RA-induced growth arrest is mainly mediated by RARalpha. The RARalpha-selective agonist Ro 40-6055 was also effective at very low concentrations (10(-10) M). Nevertheless, comparable levels of RARalpha mRNA were found in RA-responsive and -resistant BL cell lines, indicating that mechanisms different from transcriptional deregulation of RARalpha probably underlie the differential responsiveness of BL cells.

Topics: Antineoplastic Agents; B-Lymphocytes; Burkitt Lymphoma; Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Gene Transfer Techniques; Genes, myc; Herpesvirus 4, Human; Humans; Proto-Oncogene Proteins c-myc; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Signal Transduction; Tretinoin; Tumor Cells, Cultured

Fenretinide (4-HPR) is a synthetic retinoid with cancer chemopreventative potential and clinically manageable side effects, compared to the prototype retinoid, all-trans retinoic acid (RA). 4-HPR has been shown to modulate cell proliferation and induce apoptosis in a variety of human tumor cell types, but its effects on B-cell non-Hodgkin's lymphomas (NHL-B) have not been explored. Treatment of Burkitt's lymphoma Mutu I cells with 3 microM 4-HPR is accompanied by growth arrest, induction of apoptosis, and restricted progression of the cell cycle at the G(1)/S checkpoint. We also observed that 4-HPR elicited a reduced expression of bcl-6 in these cells, which supports the proposed role of bcl-6 as an anti-apoptotic gene. While 4-HPR treatment had no effect on total Rb gene expression, it significantly reduced the state of hyperphosphorylation of Rb, resulting in the predominant existence of Rb in the underphosphorylated state.

Topics: Apoptosis; Blotting, Western; Burkitt Lymphoma; Cell Cycle; Cell Division; DNA-Binding Proteins; Down-Regulation; Fenretinide; Flow Cytometry; G1 Phase; Humans; Phosphorylation; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-6; Retinoblastoma Protein; S Phase; Time Factors; Transcription Factors; Tretinoin; Tumor Cells, Cultured

CTCF is a transcriptional repressor of the c-myc gene. Although CTCF has been characterized in some detail, there is very little information about the regulation of CTCF activity. Therefore we investigated CTCF expression and phosphorylation during induced differentiation of human myeloid leukemia cells. We found that: (i) both CTCF mRNA and protein are down-regulated during terminal differentiation in most cell lines tested; (ii) CTCF down-regulation is retarded and less pronounced than that of c-myc; (iii) CTCF protein is differentially phosphorylated and the phosphorylation profiles depend on the differentiation pathway. We concluded that CTCF expression and activity is controlled at transcriptional and post-transcriptional levels.

Topics: Blotting, Northern; Blotting, Western; Burkitt Lymphoma; CCCTC-Binding Factor; Cell Differentiation; Cytarabine; Dimethyl Sulfoxide; DNA-Binding Proteins; Down-Regulation; Erythrocytes; Gene Expression Regulation; Humans; Isoelectric Focusing; Leukemia, Myeloid; Leukocytes; Megakaryocytes; Phosphorylation; Proto-Oncogene Proteins c-myc; Repressor Proteins; RNA Processing, Post-Transcriptional; Staurosporine; Tetradecanoylphorbol Acetate; Transcription Factors; Tretinoin; Tumor Cells, Cultured

The NB4 cell line, established from a patient with APL, carries the t(15; 17) and undergoes differentiation along the granulocytic pathway when exposed to retinoic acid (RA). The NB4 cell line was used as a model for exploring the expression of genes and proteins implicated in growth regulation, differentiation and apoptosis during treatment with RA. NB4 cells undergo a series of cytological and molecular alterations during RA treatment--Day 1: cell differentiation marked by an increase in CD11b is evident. Day 2: WAF1/p21 mRNA and then protein rise, though they drop 2 days later. Day 3: the percentage of cells in S phase begins to decrease and G1 arrest begins. Day 4: p53 mRNA level and then protein levels fall. Day 5: CD11b/BCL-2 double staining cells are markedly reduced. No signs of apoptosis were observed after up to 8 days of treatment with RA. These results demonstrate that NB4 cells treated with RA rapidly differentiate and arrest at G1 phase concurrent with p53-independent WAF1/p21 induction; in addition, phenotypic differentiation appears to commence before changes in cell cycle progression. An explanation for the decrease in p53 as well as the lack of apoptosis immediately after BCL-2 downregulation will require further study.

Topics: Antigens, CD; Apoptosis; Burkitt Lymphoma; Cell Cycle; Cell Differentiation; Cell Division; Cell Line; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Genes, bcl-2; Genes, p53; Humans; Kinetics; Leukemia, Promyelocytic, Acute; Macrophage-1 Antigen; Proto-Oncogene Proteins c-bcl-2; RNA, Messenger; Time Factors; Transcription, Genetic; Tretinoin; Tumor Cells, Cultured; Tumor Suppressor Protein p53

The c-fgr proto-oncogene is expressed in Burkitt's lymphoma (BL) cell and cell lines derived from them. When Epstein-Barr virus (EBV)-negative BL cell lines that contain low levels of c-fgr mRNA are infected with EBV, transcription of the c-fgr gene is further induced. In this paper we show that treatment of EBV-negative and EBV-positive BL cell lines with all-trans retinoic acid also stimulates an increase in c-fgr mRNA levels, varying between 2- and 13-fold depending on the cell line. An increase is detectable 12 to 48 h after treatment, depending on the cell line, suggesting that the c-fgr gene is not regulated directly by retinoic acid but responds to other retinoic acid-induced changes in the cell. We also show that treatment of BL cell lines with all-trans retinoic acid either results in a dose-dependent decrease in growth rate, or has no effect on growth, depending on the cell line. It has previously been suggested that the c-fgr gene product might have a role in regulating the growth of BL cells, since treatment of the EBV-positive BL cell line Daudi with alpha-interferon results in a decrease in c-fgr mRNA levels followed by a decrease in growth rate. Our data indicate that there is no general correlation between c-fgr mRNA levels and growth rate in BL cells and so argue against a role for the c-fgr gene product in growth regulation in these cells.

Topics: Burkitt Lymphoma; Cell Division; Cell Transformation, Neoplastic; Gene Expression Regulation, Neoplastic; Herpesvirus 4, Human; Humans; Proto-Oncogene Mas; Proto-Oncogenes; RNA, Messenger; Tretinoin; Tumor Cells, Cultured

Using anti-human B cell monoclonal antibodies prepared against B1 (CD20), B2 (CD21), B4 (CD19), and BB-1 (B lymphoblast antigen-1), we compared the expression of B cell differentiation antigens on a Jijoye-P3HR-1 cell line family of Burkitt's lymphomas. The expression of BB-1 and B2 antigens was faint on P3HR-1 K cell line which is an Epstein-Barr virus (EBV) high producer. On the other hand, B1 and B4 antigens were strongly expressed on it. It was also found that BB-1 expression decreased on P3HR-1 cells after activation of intracellular EBV genes by treating chemically with tumor-promoting agent (TPA) and n-butyrate, or on Raji cells on superinfection with EBV. This decrease of BB-1 was blocked by the additional treatment with retinoic acid, an inhibitor of virus replication. Dual immunofluorescence staining analysis showed that the individual cell expressing EBV-associated antigens expressed BB-1 antigen only marginally. The relationship between the change in phenotypes of host B cells and the activation of the EBV genome is discussed.

Topics: Antigens, Differentiation, B-Lymphocyte; Burkitt Lymphoma; Butyrates; Butyric Acid; Genes, Viral; Herpesvirus 4, Human; Humans; Phenotype; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured; Virus Replication

We compared the expressions of class I and class II major histocompatibility antigen complex (MHC) on the surface of Jijoye and P3HR-1 cells of Burkitt's lymphoma sublines. Jijoye cells had a large amount of class I and class II MHC antigens, whereas these antigens were less expressed on P3HR-1 cells. On a subline of P3HR-1 K cells the expression of class I antigen markedly diminished and class II antigen was undetectable. On the other hand, Jijoye, P3HR-1, and P3HR-1 K cell lines were confirmed to be Epstein-Barr virus (EBV) nonproducer, low producer, and high producer, respectively. The chemical activation of EBV genome by treating P3HR-1 cells with 12-O-tetradecanoyl phorbol-13 acetate (TPA) and n-butyrate resulted in inhibition of the expression of class I and II antigens, while the addition of retinoic acid, an inhibitor of virus replication, blocked the decrease in the MHC antigen expression. These findings suggested that there might be an inverse correlation between the virus production and the expression of class I and II MHC antigens.

Topics: Burkitt Lymphoma; Butyrates; Cell Separation; Electrophoresis, Polyacrylamide Gel; Flow Cytometry; Herpesvirus 4, Human; HLA Antigens; HLA-D Antigens; Molecular Weight; Tetradecanoylphorbol Acetate; Tretinoin; Tumor Cells, Cultured

We previously found that a minor subfraction of the human genomic DNA, corresponding to 2500-3000 nonrepetitive sequences of 3 kilobases each and designated as tumor-activated DNA (TaDNA) was transcriptionally active in Burkitt's lymphoma cells and almost inactive in normal lymphocytes growing in vitro following integration of the Epstein-Barr virus genome. Furthermore all the neoplastic cells in culture or primary neoplasms (leukemias, sarcomas, carcinomas) studied contained transcripts from most of the TaDNA sequences found in malignant lymphoblasts whereas normal cells growing in vitro contained only a few TaDNA transcripts. It is shown in the present study that treatments of the myeloid leukemia HL60 cells with various inducers of cell differentiation (dimethyl sulfoxide, retinoic acid, mezerein, 12-O-tetradecanoylphorbol-13-acetate, teleocidin) caused a dose-dependent reduction of the level of TaDNA transcripts, correlated with the diminution of c-myc transcripts. The 12-O-tetradecanoylphorbol-13-acetate treatment had this same effect on Burkitt's lymphoma cells (Raji or Namalwa) but the opposite effect on normal cells (Epstein-Barr virus-immortalized lymphocytes or fetal fibroblasts) where it enhanced the formation of Ta-DNA transcripts up to the levels found in untreated malignant cells. These data suggest two conclusions (a) TaDNA corresponds to a multigenic set which seems to be involved in modulation of the malignant phenotype and (b) depending on the origin of the cells, agents like 12-O-tetradecanoylphorbol-13-acetate may operate either as tumor promoters or as differentiation inducers through the control of TaDNA expression.

Topics: Actins; Burkitt Lymphoma; Carcinogens; Cell Differentiation; Cell Division; Cell Line; Dimethyl Sulfoxide; Diterpenes; DNA, Neoplasm; Gene Expression Regulation; Histocompatibility Antigens Class II; HLA-DR Antigens; Humans; Lyngbya Toxins; Proto-Oncogenes; Terpenes; Tetradecanoylphorbol Acetate; Transcription, Genetic; Tretinoin

Teleocidin, a new potent tumor promoter, produces biological effects similar to 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on human lymphoblastoid cell lines. A wide range of concentrations (4-16 ng/ml) of teleocidin were optimal for induction of replication of latent Epstein-Barr virus (EBV) genomes in P3HR-1 cells; cell growth was significantly inhibited in this dose range. In contrast, treatment of Raji cells with an identical dose range of teleocidin did not induce replication of latent EBV genomes. As with TPA, P3HR-1 cells in the stationary phase were twice as responsive to teleocidin induction as exponentially growing cells. The activation of P3HR-1 cells both by teleocidin and TPA greatly enhanced the synthesis of EBV DNA and EBV-associated polypeptides as determined by cRNA - DNA hybridization and by analysis on polyacrylamide gels. Both drugs also increased production of biologically active virus as monitored by the synthesis of viral DNA in superinfected Raji cells. These effects were completely inhibited by retinoic acid. However, retinoic acid did not inhibit the spontaneous viral DNA replication that occurs in P3HR-1 cells not treated with the inducers. Thus, it appears that retinoic acid antagonizes the inducing effects of TPA and teleocidin, but not viral replication itself.

Topics: Alkaloids; Burkitt Lymphoma; Carcinogens; Cell Line; Cell Survival; DNA Replication; Drug Antagonism; Genes, Viral; Herpesvirus 4, Human; Humans; Lyngbya Toxins; Phorbols; Tetradecanoylphorbol Acetate; Tretinoin; Virus Replication

We have studied the effects of retinoic acid (RA) on bone marrow leukemic cells from children with acute nonlymphocytic leukemia (ANLL) at the time of diagnosis, and on cells from four ALL/lymphoma cell lines (common-ALL, pre-B-ALL, T-ALL, and Burkitt's lymphoma) derived from children with these diseases. Cells were cultured in methylcellulose medium with clinically attainable concentrations (0.25-2.0 microM) of RA for two weeks prior to colony and cluster quantitation. Myeloid progenitor cells (CFU-GM) obtained from children with hematologically normal bone marrows were also cultured with RA. Of 19 patients with ANLL whose cells formed colonies, 16 (84%) were inhibited by RA; three patients showed either increased or unchanged colony numbers with RA. RA had a similar effect on both ANLL cluster and colony growth. RA (1-2 microM) also inhibited colony growth of the pre-B-ALL, common-ALL, and Burkitt's lymphoma lines; the T-ALL line and normal bone marrow CFU-GM were not inhibited. The inhibitory effects of RA on pediatric ANLL bone marrow cells and on some ALL/lymphoma cell lines compared with CFU-GM indicate that RA may be of value in the treatment of these malignancies in children.

Topics: B-Lymphocytes; Bone Marrow; Burkitt Lymphoma; Cell Division; Cell Line; Child; Colony-Forming Units Assay; Hematopoietic Stem Cells; Humans; Leukemia, Lymphoid; Leukemia, Myeloid, Acute; T-Lymphocytes; Tretinoin

2',5'-Oligoadenylate (2-5A) synthetase, which polymerizes adenosine triphosphate into 2-5A, is induced upon treatment of cells with interferon (IFN) and is thought to be involved in its antiviral and anticellular action. We report here that retinoic acid (RA) enhanced the level of this enzyme in two human transformed cell lines, WISH and Namalva. Like IFN, RA induced 2-5A synthetase activity in a time- and dose-dependent manner. Addition of anti IFN-alpha, -IFN-beta, or -IFN-gamma antibodies to the medium concomitantly with RA did not prevent such induction; therefore, the effect of RA is clearly not mediated through the induction and externalization of IFN. Pretreatment of cells with actinomycin D inhibited 2-5A synthetase induction by RA, suggesting that RA increased the transcription of the 2-5A synthetase gene. In WISH cells, the growth of encephalomyocarditis virus was inhibited by RA treatment, which is consistent with the hypothesis that 2-5A synthetase plays an important role in the antiviral action of IFN, at least in encephalomyocarditis virus replication. When the anticellular effects of IFN and RA were compared to their ability to induce 2-5A synthetase activity in four human cell lines, there was no strict correlation between the amplitude of the enzyme activity induced and the extent of the antiproliferative effect. It is concluded that the 2-5A system is probably not the only pathway responsible for the antiproliferative effect of both substances. We further suggest that the induction of 2-5A synthetase by IFN and RA might be connected with at least some of the similarities observed between other biological effects of both compounds.

Topics: 2',5'-Oligoadenylate Synthetase; Burkitt Lymphoma; Cell Division; Cell Line; Cell Transformation, Neoplastic; Enzyme Induction; Female; Fibroblasts; Humans; Interferon Type I; Interferon-gamma; Leukemia, Myeloid, Acute; Placenta; Pregnancy; Tretinoin

Necessary for growth and differentiation in many normal tissues and capable of inducing differentiation in human promyelocytic cell lines, retinoids were the subject of this study. Specifically, effects of 13-cis-retinoic acid and 13-trans-retinoic acid on the growth of normal human bone marrow cells in soft-agar system were studied. Both short-term incubation and continuous exposure to retinoic acid caused a decreased number of granulocyte colonies and an increased cluster-to-colony ratio. This effect was concentration-dependent. Examination of specimens stained with Wright-Giemsa or nitro blue tetrazolium stains showed a progressive increase in the percentage of immature granulocytic precursors with increasing concentrations of retinoic acid. No effect of retinoic acid was seen on a number of human tumor cell lines. Retinoic acid blocked both differentiation and proliferation and appeared to do so by specific, noncytotoxic mechanisms in normal human bone marrow cells.

Topics: Bone Marrow; Bone Marrow Cells; Burkitt Lymphoma; Cell Division; Cell Line; Clone Cells; Colony-Forming Units Assay; Colony-Stimulating Factors; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Humans; Leukemia, Myeloid; Melanoma; Multiple Myeloma; Osteosarcoma; Tretinoin

Corticosteroids can induce the synthesis of EBV antigens in the Burkitt lymphoma line Daudi. As early as 12 h after application of the drug, an increase of EA-positive cells can be seen, the maximum induction being reached after 2 days. Nanogram amounts per ml of hormone are sufficient for measurable effects. Early antigen induction by corticosteroids does not require replication of viral DNA. Induction by corticosteroid differs from induction by other systems in two major respects: (1) it does not cooperate with other inducers, and (2) it is specifically inhibited by 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Induction by corticosteroids, however, shares at least one retinoic acid-sensitive step with induction by chemicals such as TPA, 5-iodo-2-deoxyuridine (IdUrd), n-butyric acid (n-BA) or inducing serum factor. This study defines three qualitatively different effects of TPA in Daudi cells: an inhibitory effect on EBV induction by corticosteroids and two differential types of synergistic effects with serum factor or n-BA, respectively. In this particular cell line, TPA exhibits no inducing capacity when applied alone.

Topics: Adrenal Cortex Hormones; Animals; Antigens, Viral; Burkitt Lymphoma; Cell Line; Dose-Response Relationship, Drug; Drug Synergism; Humans; Kinetics; Phorbols; Tetradecanoylphorbol Acetate; Tretinoin; Virus Activation

Retinoic acid (RA) suppressed the production of interferon (IFN) alpha and IFN gamma of human peripheral blood leukocytes in response to stimulation with lectin mitogens, bacterial products, synthetic polynucleotides, viruses, and tumor cell lines in vitro. Virus-induced secretion of IFN alpha of human lymphoblastoid cells was also inhibited. RA-mediated suppression was dose-dependent and required the near-concurrent addition of RA and inducers to human leukocyte cultures, thus suggesting that RA affects an early cellular function in the generation of IFN. Implications of these findings for the use of retinoids in the treatment of human malignancies are discussed.

Topics: Burkitt Lymphoma; Cell Line; Depression, Chemical; Humans; In Vitro Techniques; Interferons; Leukocytes; Mitogens; Neoplasms, Experimental; Polynucleotides; Tretinoin; Virus Diseases

12-O-tetradecanoyl-phorbol-13-acetate (TPA), a potent tumour promoter, was tested for its effects on the proliferation of the human Burkitt lymphoma cell line, Namalwa, and the synthesis of interferon by these cells. At nanomolar concentrations, TPA blocked thymidine incorporation into cellular DNA by more than 90% within 24 h. TPA-treated cells produced about 20-fold more interferon in response to Sendai virus than did untreated controls and simultaneous treatment with TPA and sodium n-butyrate gave a further two- to three-fold enhancement. Neither of these effects of TPA was reversed on removal of the compound; furthermore, exposure of Namalwa cells to TPA for only 1 h was sufficient for full activity. 4-O-methyl-TPA, a compound only marginally active as a tumour promoter, showed effects similar to TPA, but only at concentrations 300-fold higher. In contrast to its effects on Namalwa cells, TPA did not affect synthesis of interferon in response to Sendai virus in two other Burkitt lymphoma lines (Raji and Daudi) nor in the Epstein-Barr virus (EBV)-negative lymphoma line, BJAB; it inhibited interferon production in the human myeloid cell line, HL-60.

Topics: Burkitt Lymphoma; Butyrates; Cell Line; DNA; Humans; Interferons; Lymphoma; Melitten; Parainfluenza Virus 1, Human; Phorbols; Tetradecanoylphorbol Acetate; Tretinoin