tretinoin and tamibarotene

In the last 2 decades an increasing number of patients reported with extramedullary involvement among relapsed acute promyelocytic leukemia (APL) patients. Several investigators related this phenomenon to the relatively new treatment of all-trans-retinoic-acid (ATRA). In this review article we will examine what has been reported in the medical literature on extramedullary disease in APL: the common sites to be involved, the clinical risk factors to its development, the role of ATRA and arsenic tri-oxide and the recommended treatment.

Topics: Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Benzoates; Cerebral Hemorrhage; Humans; Incidence; Leukemia, Promyelocytic, Acute; Leukemic Infiltration; Models, Biological; Multicenter Studies as Topic; Organ Specificity; Oxides; Prognosis; Randomized Controlled Trials as Topic; Remission Induction; Risk Factors; Tetrahydronaphthalenes; Tretinoin

Acute myeloblastic leukemia (AML) is a disease which may be completely cured by intensive chemotherapy or stem cell transplantation. However, the prognoses are poor in elderly, refractory or recurrence cases. Molecular targeted drugs have been expected to improve the prognoses of patients with various cancers, but there are few kinds of molecular target drugs for AML. On the other hand, excellent drug exists such as tretinoin for acute promyelocytic leukemia. Molecular mechanisms have been elucidated in AML cells, and the molecules which can be the good target of the treatment have been identified. Novel molecular target drugs are also expected.

Topics: Aminoglycosides; Antibodies, Monoclonal, Humanized; Benzoates; Gemtuzumab; Humans; Leukemia, Myeloid, Acute; Molecular Targeted Therapy; Tetrahydronaphthalenes; Tretinoin

Topics: Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Benzoates; Clinical Trials, Phase III as Topic; Consolidation Chemotherapy; Disseminated Intravascular Coagulation; Gene Fusion; Humans; Induction Chemotherapy; Leukemia, Promyelocytic, Acute; Maintenance Chemotherapy; Molecular Targeted Therapy; Nuclear Proteins; Oxides; Promyelocytic Leukemia Protein; Receptors, Retinoic Acid; Recurrence; Remission Induction; Retinoic Acid Receptor alpha; Tetrahydronaphthalenes; Transcription Factors; Tretinoin; Tumor Suppressor Proteins

Acute promyelocytic leukemia (APL) is characterized by generation of the PML-RARalpha fusion gene. PML-RARalpha can homodimerize with another PML-RARalpha, and the hybrid binds the histone-deacetylase recruiting co-repressor complex with higher affinity than the wild-type RARalpha. However, the co-repressor complex is releasable by pharmacological doses of all-trans retinoic acid (ATRA). More than 90% of patients with APL achieve a complete remission (CR) with differentiation therapy consisting of ATRA combined with chemotherapy. A new synthetic retinoid, tamibaroten, showed therapeutic effectiveness in patients with ATRA-resistant APL with increased expression of cellular retinoic acid binding protein (CRABP), and about 60% of patients with relapsed APL achieved a CR. Arsenic trioxide triggers the rapid degradation of PML-RARalpha through the targeting of the PML moieties of the fusion protein and showed a high CR rate in relapsed APL. The combination of ATRA, chemotherapy, and/or new agents improved the long-term survival in patients with APL.

Topics: Animals; Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Benzoates; Humans; Leukemia, Promyelocytic, Acute; Oncogene Proteins, Fusion; Oxides; Tetrahydronaphthalenes; Tretinoin

Retinoid is a collective term for compounds which bind to and activate retinoic acid receptors (RARalpha, beta, gamma and RXRalpha, beta, gamma), members of nuclear hormone receptor superfamily. The most important endogeneous retinoid is all-trans-retinoic acid (ATRA) which is an RARalpha, beta and gamma ligand. ATRA and its mimics have been in clinical use for treatment of acute promyelocytic leukemia (APL) and some skin diseases. Many synthetic retinoids have been developed and attempts to improve their medicinal properties have been made. Among them, tamibarotene (Am80) is an RARalpha- and RARbeta-specific (but RARgamma- and RXRs-nonbinding) synthetic retinoid that is effective in the treatment of psoriasis patients and relapsed APL. Experimentally, this compound is also active in animal models of rheumatoid arthritis and experimental autoimmune encephalomyelitis. On this background, possible application of retinoids for the treatment of autoimmune diseases was discussed. In particular, Th1 dominant autoimmune diseases may be the targets of the retinoids.

Topics: Animals; Arthritis, Rheumatoid; Autoimmune Diseases; Benzoates; Humans; Leukemia, Promyelocytic, Acute; Receptors, Retinoic Acid; Retinoids; Skin Diseases; T-Lymphocytes; Tetrahydronaphthalenes; Tretinoin

Topics: Aminoglycosides; Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Benzoates; Clinical Trials as Topic; Combined Modality Therapy; Drug Resistance, Neoplasm; Enzyme Inhibitors; Gemtuzumab; Hematopoietic Stem Cell Transplantation; Humans; Hydroxamic Acids; Leukemia, Promyelocytic, Acute; Oxides; Practice Guidelines as Topic; Recurrence; Remission Induction; Tetrahydronaphthalenes; Tretinoin

Topics: Alkyl and Aryl Transferases; Aminoglycosides; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Benzoates; Cyclosporine; Cytarabine; Daunorubicin; Drug Design; Farnesyltranstransferase; Gemtuzumab; Humans; Leukemia, Myeloid, Acute; Neoplasm Recurrence, Local; Nucleosides; Oxides; Prognosis; Radioisotopes; Remission Induction; Tetrahydronaphthalenes; Topoisomerase Inhibitors; Tretinoin; Verapamil

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

All-trans retinoic acid (ATRA), a potent differentiating drug for acute promyelocytic leukemia (APL), induces a high incidence of complete remission (CR) in patients with APL and is now established as a first-line therapy. However, ATRA resistance has become a clinical problem. Patients who relapsed after ATRA-induced CR have had difficulty in obtaining a second CR with ATRA therapy. Although several mechanisms have been postulated, treatment strategies to overcome resistance have not been established. We used a new synthetic retinoid, Am-80, as reinduction therapy for APL relapse after from ATRA-induced CR. Am-80 was several times more potent than ATRA in inducing differentiation in vitro. At a 6 mg/m2 dose, there were 24 evaluable patients; 14 (58%) achieved CR between days 20 and 58 (median, 37 days). Clinical response correlated with the in vitro response to Am-80. Adverse effects included retinoic acid syndrome (n = 1), hyperleukocytosis (n = 1), xerosis (n = 9), cheilitis (n = 8), hypertriglyceridemia (n = 16), and hypercholesterolemia (n = 15). Am-80 is active in APL after relapse from ATRA-induced CR. Further clinical trials are needed to establish strategies to overcome ATRA resistance.

Topics: Adult; Aged; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Arsenicals; Benzoates; Biomarkers, Tumor; Cheilitis; Cytarabine; Daunorubicin; Disease-Free Survival; Drug Resistance, Neoplasm; Female; Humans; Hypercholesterolemia; Hypertriglyceridemia; Leukemia, Promyelocytic, Acute; Leukocytosis; Male; Middle Aged; Neoplasm Proteins; Oncogene Proteins, Fusion; Pilot Projects; Recurrence; Remission Induction; Salvage Therapy; Tetrahydronaphthalenes; Treatment Outcome; Tretinoin; Tumor Cells, Cultured

Treatment of acute promyelocytic leukaemia (APL) with arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) is highly effective first-line therapy, although approximately 5-10% of patients relapse. Tamibarotene is a synthetic retinoid with activity in APL patients who relapse after chemotherapy and ATRA, but has not been studied in relapse after treatment with ATO and ATRA. We report on a phase II study of tamibarotene in adult patients with relapsed or refractory APL after treatment with ATRA and ATO (n = 14). Participants were treated with tamibarotene (6 mg/m(2) /d) during induction and for up to six cycles of consolidation. The overall response rate was 64% (n = 9), the rate of complete cytogenetic response was 43% (n = 6) and the rate of complete molecular response was 21% (n = 3). Relapse was frequent with 7 of 9 responders relapsing after a median of 4·6 months (range 1·6-26·8 months). The median event-free survival (EFS) was 3·5 months [95% confidence interval (CI) 0-8·6 months] and the median overall survival (OS) was 9·5 months (95% CI 5·9-13·1 months). These results demonstrate that tamibarotene has activity in relapsed APL after treatment with ATO and ATRA and further studies using tamibarotene as initial therapy and in combination with ATO are warranted.

Topics: Adult; Aged; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Benzoates; Biomarkers, Tumor; Cardiovascular Diseases; Cell Differentiation; Combined Modality Therapy; Consolidation Chemotherapy; Disease-Free Survival; Drug Resistance, Neoplasm; Febrile Neutropenia; Female; Hematopoietic Stem Cell Transplantation; Humans; Kaplan-Meier Estimate; Leukemia, Promyelocytic, Acute; Male; Middle Aged; Oncogene Proteins, Fusion; Oxides; Recurrence; Remission Induction; Salvage Therapy; Tetrahydronaphthalenes; Tretinoin

A new synthetic retinoid, Am80, is effective in treating acute promyelocytic leukemia relapsed from all-trans-retinoic acid-induced complete remission (CR). We report here the long-term clinical outcomes of patients who achieved second CR with Am80. Of 24 evaluable patients, 14 achieved a second CR by Am80 therapy. Of those patients, 4 relapsed within 6 months, despite subsequent consolidation chemotherapy. Six patients underwent sibling or unrelated HLA-matched allogeneic bone marrow transplantation (BMT), and 4 are alive without relase for more than 49 months after achieving second CR. Four of 8 patients who did not receive BMT are alive without relapse for more than 49 months. Promyelocytic leukemia-retinoic acid receptor alpha (PML-RAR alpha) fusion transcript was undetectable by reverse transcriptase-polymerase chain reaction in all living patients. Therefore, if patients achieve second CR with Am80 and HLA-matched donors are available, BMT is the treatment of choice. However, it is noteworthy that CR was maintained for more than 49 months in half of the patients who did not receive BMT.

Topics: Adult; Aged; Antineoplastic Agents; Benzoates; Female; Follow-Up Studies; Humans; Leukemia, Promyelocytic, Acute; Male; Middle Aged; Prognosis; Recurrence; Remission Induction; Retinoids; Tetrahydronaphthalenes; Tretinoin

All-trans retinoic acid (ATRA), a potent differentiating drug for acute promyelocytic leukemia (APL), induces a high incidence of complete remission (CR) in patients with APL and is now established as a first-line therapy. However, ATRA resistance has become a clinical problem. Patients who relapsed after ATRA-induced CR have had difficulty in obtaining a second CR with ATRA therapy. Although several mechanisms have been postulated, treatment strategies to overcome resistance have not been established. We used a new synthetic retinoid, Am-80, as reinduction therapy for APL relapse after from ATRA-induced CR. Am-80 was several times more potent than ATRA in inducing differentiation in vitro. At a 6 mg/m2 dose, there were 24 evaluable patients; 14 (58%) achieved CR between days 20 and 58 (median, 37 days). Clinical response correlated with the in vitro response to Am-80. Adverse effects included retinoic acid syndrome (n = 1), hyperleukocytosis (n = 1), xerosis (n = 9), cheilitis (n = 8), hypertriglyceridemia (n = 16), and hypercholesterolemia (n = 15). Am-80 is active in APL after relapse from ATRA-induced CR. Further clinical trials are needed to establish strategies to overcome ATRA resistance.

Topics: Adult; Aged; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Arsenicals; Benzoates; Biomarkers, Tumor; Cheilitis; Cytarabine; Daunorubicin; Disease-Free Survival; Drug Resistance, Neoplasm; Female; Humans; Hypercholesterolemia; Hypertriglyceridemia; Leukemia, Promyelocytic, Acute; Leukocytosis; Male; Middle Aged; Neoplasm Proteins; Oncogene Proteins, Fusion; Pilot Projects; Recurrence; Remission Induction; Salvage Therapy; Tetrahydronaphthalenes; Treatment Outcome; Tretinoin; Tumor Cells, Cultured

Differentiation therapy with all-trans retinoic acid (ATRA) has marked a major advance and become the first choice drug in the treatment of acute promyelocytic leukemia (APL). However, patients who relapse from ATRA-induced complete remission (CR) have difficulty in obtaining a second CR with a second course of ATRA therapy alone. We tested the efficacy of a new synthetic retinoid, Am80, in APL that had relapsed from CR induced by ATRA in a prospective multicenter study. Am80 is approximately 10 times more potent than ATRA as an in vitro differentiation inducer, is more stable to light, heat, and oxidation than ATRA, has a low affinity for cellular retinoic acid binding protein, and does not bind to retinoic acid receptor-gamma. Patients received Am80, 6 mg/m2, orally alone daily until CR. Of 24 evaluable patients, 14 (58%) achieved CR. The interval from the last ATRA therapy was not different between CR and failure cases. The clinical response was well correlated with the in vitro response to Am80 in patients examined. Adverse events included 1 retinoic acid syndrome, 1 hyperleukocytosis, 9 xerosis, 8 cheilitis, 16 hypertriglyceridemia, and 15 hypercholesterolemia, but generally milder than those of ATRA, which all patients had received previously. Am80 is effective in APL relapsed from ATRA-induced CR and deserves further trials, especially in combination with chemotherapy.

Topics: Adult; Aged; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Benzoates; Cell Differentiation; Chemical and Drug Induced Liver Injury; Combined Modality Therapy; Cytarabine; Daunorubicin; Drug Resistance, Neoplasm; Female; Gastrointestinal Diseases; Humans; Leukemia, Promyelocytic, Acute; Leukocytosis; Male; Middle Aged; Pain; Prospective Studies; Receptors, Retinoic Acid; Recurrence; Remission Induction; Retinoic Acid Receptor gamma; Retinoids; Salvage Therapy; Tetrahydronaphthalenes; Treatment Outcome; Tretinoin

Peretinoin is an acyclic retinoid that stimulates retinoic acid receptors (NR1Bs) and produces therapeutic effects on hepatocellular cancer. We have previously shown that NR1B agonists such as Am80 and all trans-retinoic acid suppress pathogenic events in intracerebral hemorrhage. The present study addressed the actions of peretinoin and Am80 against cytotoxicity of a blood protease thrombin on cortico-striatal slice cultures obtained from neonatal rat brains. Application of 100 U/ml thrombin to the slice cultures for 72 h caused cell death in the cortical region and tissue shrinkage in the striatal region. Peretinoin (50 μM) and Am80 (1 μM) counteracted these cytotoxic effects of thrombin, and the effect of peretinoin and Am80 was blocked by LE540, an NR1B antagonist. A broad-spectrum kinase inhibitor K252a (3 μM) attenuated the cytoprotective effect of peretinoin in the cortical region, whereas a specific protein kinase A inhibitor KT5720 (1 μM) attenuated the protective effect of peretinoin in the cortical and the striatal regions. On the other hand, nuclear factor-κB (NF-κB) inhibitors such as pyrrolidine dithiocarbamate (50 μM) and Bay11-7082 (10 μM) prevented thrombin-induced shrinkage of the striatal region. Peretinoin and Am80 as well as Bay11-7082 blocked thrombin-induced nuclear translocation of NF-κB in striatal microglia and loss of striatal neurons. We also found that daily administration of peretinoin reduced histopathological injury and alleviated motor deficits in a mouse model of intracerebral hemorrhage. These results indicate that NR1B agonists including peretinoin may serve as a therapeutic option for hemorrhagic brain injury.

Topics: Animals; Antineoplastic Agents; Brain; Brain Injuries; Cerebral Hemorrhage; Mice; NF-kappa B; Rats; Thrombin; Tretinoin

We designed and synthesized a series of retinobenzoic acids bearing various silyl functionalities in order to explore in detail the structure-activity relationship (SAR) at the hydrophobic moiety of retinoids. Among the synthesized compounds, 24 c bearing a t-butyldimethylsilyl (TBS) group at the hydrophobic site exhibited potent retinoid activity comparable to that of the lead compound Am555S (4). Compound 24 c exhibited transcription-promoting activity towards all three subtypes of retinoic acid receptor (RAR), but showed the highest activity towards RARγ, in contrast to the high RARα-selectivity of Am80 (3) and Am555S (4). The SARs presented here should be helpful in the development of subtype-selective retinoids, and in particular 24 c might be a promising lead compound for new RARγ ligands.

Topics: Benzoates; Retinoid X Receptors; Retinoids; Silicon; Structure-Activity Relationship; Tetrahydronaphthalenes; Tretinoin

Noise is one of the most common causes of hearing loss in industrial countries. There are many studies about chemical agents to prevent noise-induced hearing loss (NIHL). However, there is no commercially available drug yet. Retinoic acid is an active metabolite of Vitamin A; it has an anti-apoptic role in NIHL. This study aims to verify the differences among selective agonists of retinoic acid receptors (RARs) in NIHL. All-trans retinoic acid (ATRA), AM80 (selective retinoic acid receptor α agonist), AC261066 (Selective retinoic acid receptor β1 agonist), and CD1530 (Selective retinoic acid λ agonist) were injected to 6-7 weeks old CJ5BL/6 mice before noise (110 dB for 3 h) exposure. In the auditory brainstem response test pre-, post 1, 3, and 7 days after noise exposure, not only ATRA but all kinds of selective RAR agonists showed protective effects in hearing threshold and wave I amplitude. Though there was no significant difference in the level of protective effects between agonists, α agonist showed the most prominent effect in preserving hearing function as well as outer hair cells after noise exposure. In conclusion, selective agonists of RAR demonstrate comparable protective effects against NIHL to retinoic acid. Given that these selective RAR agonists have less side effects than retinoic acid, they may be promising potential drugs against NIHL.

Topics: Animals; Benzoates; Hearing Loss, Noise-Induced; Mice, Inbred C57BL; Naphthols; Noise; Receptors, Retinoic Acid; Tetrahydronaphthalenes; Thiazoles; Tretinoin

Retinoic acid (RA) is converted from retinal by retinaldehyde dehydrogenases (RALDHs) and is an essential signaling molecule in embryonic and adult tissue. We previously reported that RALDH1 was produced in the rat anterior pituitary gland and hypothesized that RA was generated in the gland. Midkine (MK) is an RA-inducible growth factor, and MK production in the rat anterior pituitary gland was recently reported. However, the mechanism that regulates gene expression of MK in the pituitary gland has not been determined. To investigate regulation of MK production in the anterior pituitary gland, we analyzed changes in MK mRNA in cultured rat anterior pituitary cells. We identified MK-expressing cells by double-staining with in situ hybridization and immunohistochemical techniques for RALDH1. MK mRNA was expressed in RALDH1-producing cells in the anterior pituitary gland. Using isolated anterior pituitary cells of rats, we examined the effect of RA on gene expression of MK. Quantitative real-time PCR revealed that 72 h exposure to a concentration of 10

Topics: 2-Naphthylamine; Aldehyde Dehydrogenase 1 Family; Animals; Benzoates; Cells, Cultured; Gene Expression Regulation; Intercellular Signaling Peptides and Proteins; Kinetics; Male; Midkine; Nerve Growth Factors; Nerve Tissue Proteins; Neurons; Pituitary Gland, Anterior; Pyrimidines; Rats, Wistar; Receptors, Retinoic Acid; Retinal Dehydrogenase; Retinaldehyde; RNA, Messenger; Signal Transduction; Tetrahydronaphthalenes; Tretinoin; Up-Regulation

Retinoic Acid Receptor alpha (RARα/NR1B1), Retinoic Acid Receptor beta (RARβ/NR1B2) and Retinoic Acid Receptor gamma (RARγ/NR1B3) are transcription factors regulating gene expression in response to retinoids. Within the RAR genomic pathways, binding of RARs to coregulators is a key intermediate regulatory phase. However, ligand-dependent interactions between the wide variety of coregulators that may be present in a cell and the different RAR subtypes are largely unknown. The aim of this study is to characterize the coregulator binding profiles of RARs in the presence of the pan-agonist all-trans-Retinoic Acid (AtRA); the subtype-selective agonists Am80 (RARα), CD2314 (RARβ) and BMS961 (RARγ); and the antagonist Ro415253. To this end, we used a microarray assay for coregulator-nuclear receptor interactions to assess RAR binding to 154 motifs belonging to >60 coregulators. The results revealed a high number of ligand-dependent RAR-coregulator interactions among all RAR variants, including many binding events not yet described in literature. Next, this work confirmed a greater ligand-independent activity of RARβ compared to the other RAR subtypes based on both higher basal and lower ligand-driven coregulator binding. Further, several coregulator motifs showed selective binding to a specific RAR subtype. Next, this work showed that subtype-selective agonists can be successfully discriminated by using coregulator binding assays. Finally this study demonstrated the possible applications of a coregulator binding assay as a tool to discriminate between agonistic/antagonistic actions of ligands. The RAR-coregulator interactions found will be of use to direct further studies to better understand the mechanisms driving the eventual actions of retinoids.

Topics: Amino Acid Motifs; Anthracenes; Benzoates; Binding Sites; Chromans; Protein Array Analysis; Protein Binding; Protein Domains; Receptors, Retinoic Acid; Recombinant Proteins; Response Elements; Retinoic Acid Receptor alpha; Retinoic Acid Receptor gamma; Retinoids; Structure-Activity Relationship; Tetrahydronaphthalenes; Thiophenes; Tretinoin

After lesions to the mammalian optic nerve, the great majority of retinal ganglion cells (RGCs) die before their axons have even had a chance to regenerate. Frog RGCs, on the other hand, suffer only an approximately 50% cell loss, and we have previously investigated the mechanisms by which the application of growth factors can increase their survival rate. Retinoic acid (RA) is a vitamin A-derived lipophilic molecule that plays major roles during development of the nervous system. The RA signaling pathway is also present in parts of the adult nervous system, and components of it are upregulated after injury in peripheral nerves but not in the CNS. Here we investigate whether RA signaling affects long-term RGC survival at 6 weeks after axotomy. Intraocular injection of all-trans retinoic acid (ATRA), the retinoic acid receptor (RAR) type-α agonist AM80, the RARβ agonist CD2314, or the RARγ agonist CD1530, returned axotomized RGC numbers to almost normal levels. On the other hand, inhibition of RA synthesis with disulfiram, or of RAR receptors with the pan-RAR antagonist Ro-41-5253, or the RARβ antagonist LE135E, greatly reduced the survival of the axotomized neurons. Axotomy elicited a strong activation of the MAPK, STAT3 and AKT pathways; this activation was prevented by disulfiram or by RAR antagonists. Finally, addition of exogenous ATRA stimulated the activation of the first two of these pathways. Future experiments will investigate whether these strong survival-promoting effects of RA are mediated via the upregulation of neurotrophins.

Topics: Animals; Anura; Benzoates; Chromans; Naphthols; Nerve Regeneration; Optic Nerve; Optic Nerve Injuries; Receptors, Retinoic Acid; Retinal Ganglion Cells; Tetrahydronaphthalenes; Tretinoin

Several inducers have been used to differentiate embryonic stem cells (ESCs) into male germ cells but the induction process has been inefficient. To solve the problem of low efficiency of inducer for ESCs differentiation into male germ cells, all-trans retinoic acid (ATRA), Am80(the retinoic acid receptor agonist), and estradiol (E2) was used to induce ESCs to differentiate into male germ cells in vitro. ESCs were cultured in media containing ATRA, Am80, or E2 respectively which can differentiate ESCs into a germ cell lineage. In process of ATRA and Am80 induction Group, germ cell-like cells can be observed in 10 days; but have no in E2 induction Group. The marker genes of germ cell: Dazl, Stra8, C-kit, Cvh, integrinα6, and integrinβ1 all showed a significant up-regulation in the expression level. The ATRA-induction group showed high expression of C-kit and Cvh around 4 days, and integrinα6 and integrinβ1 were activated on day 10, respectively, while the E2-,Am80- induction group showed a high expression of C-kit as early as 4 days immunocytochemistry results shown that, integrinα6 and integrinβ1 could be detected in the ATRA-, Am80-, and E2-induction group, Positive clones in the ATRA group were greater in number than those in the other two groups. we conclued that ATRA, Am80, and E2 can promote the expression of the corresponding genes of germ cells, and had different effect on the differentiation of ESCs into male germ cells. ATRA was the most effective inducer of germ cell differentiation.

Topics: Adaptor Proteins, Signal Transducing; Animals; Benzoates; Cell Differentiation; Chick Embryo; Chickens; Embryonic Stem Cells; Estradiol; Germ Cells; Immunohistochemistry; Integrins; Lewis X Antigen; Male; Microscopy, Fluorescence; Nanog Homeobox Protein; Proto-Oncogene Proteins c-kit; RNA-Binding Proteins; Tetrahydronaphthalenes; Tretinoin; Up-Regulation

To determine whether all-trans retinoic acid or a synthetic retinoic acid receptor-α/β-specific agonist, Am80, can reduce the degree of experimental autoimmune optic neuritis in mice with experimental autoimmune encephalomyelitis.. Optic neuritis was induced in C57BL/6 mice by immunizing them with myelin oligodendrocyte glycoprotein35-55 . All-trans retinoic acid (350 μg/mouse/time point) or Am80 (5 mg/kg/time point) was administered every other day from day 0 to day 20. The degree of experimental autoimmune encephalomyelitis was scored and histopathological analysis of the optic neuritis was performed on day 22 after the immunization. In vivo-primed draining lymph node cells obtained from vehicle-treated or all-trans retinoic acid-treated mice were stimulated with myelin oligodendrocyte glycoprotein35-55 , and the culture supernatant was collected for assays of interferon-γ and interleukin-17.. All-trans retinoic acid treatment significantly reduced the clinical score of experimental autoimmune encephalomyelitis and the severity of the optic neuritis by histopathological analysis. The production of interferon-γ and interleukin-17 was significantly reduced in all-trans retinoic acid-treated mice compared with vehicle-treated mice. Am80 treatment also significantly decreased the severity of the optic neuritis in mice with experimental autoimmune encephalomyelitis.. These findings demonstrate that all-trans retinoic acid and Am80 treatment were able to reduce the severity of optic neuritis in mice with experimental autoimmune encephalomyelitis. Activation of retinoic acid receptor-α/β may be a molecular target for the treatment of autoimmune optic neuritis induced by Th1 or Th17-dominated immune responses.

Topics: Animals; Benzoates; Encephalomyelitis, Autoimmune, Experimental; Female; Flow Cytometry; Injections, Intraperitoneal; Interferon-gamma; Interleukin-17; Mice; Mice, Inbred C57BL; Neuritis, Autoimmune, Experimental; Oligonucleotide Array Sequence Analysis; Optic Neuritis; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Superoxide Dismutase; Superoxide Dismutase-1; Tetrahydronaphthalenes; Tretinoin

To improve the outcome of cancer chemotherapy, strategies to enhance the efficacy of anticancer drugs are required. Sorafenib is the only drug to prolong overall survival of the patients with hepatocellular carcinoma (HCC), however, the outcome is still not satisfactory. Retinoids, vitamin A derivatives, have been known to exhibit inhibitory effects on various cancers including HCC. In this study, we investigated the effects of combined treatment using sorafenib and retinoids including all-trans retinoic acid (ATRA), NIK-333, and Am80 on HCC cells. Cell viability assays in six HCC cell lines, HepG2, PLC/PRF/5, HuH6, HLE, HLF, and Hep3B, revealed that 5 and 10 μM ATRA, concentrations that do not exert cytotoxic effects, enhanced the cytotoxicity of sorafenib, being much more effective than NIK-333 and Am80. We found that ATRA induced AMP-activated protein kinase activation, which was followed by reduced intracellular ATP level. Gene expression analysis revealed that ATRA decreased the expression of glycolytic genes such as GLUT-1 and LDHA. In the combination treatment using ATRA and sorafenib, increased apoptosis, followed by the activation of p38 MAPK and JNK, the upregulation and translocation of Bax to mitochondria, and the activation of caspase-3, was observed. Suppression of AMP-activated protein kinase by siRNA restored the viability of the cells treated with ATRA and sorafenib. Our results thus indicate that ATRA is useful for enhancing the cytotoxicity of sorafenib against HCC cells by regulating the energy metabolism of HCC cells.

Topics: Adenosine Triphosphate; AMP-Activated Protein Kinases; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; bcl-2-Associated X Protein; Benzoates; Carcinoma, Hepatocellular; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Glucose Transporter Type 1; Humans; Liver Neoplasms; Niacinamide; Phenylurea Compounds; Retinoids; Sorafenib; Tetrahydronaphthalenes; Tretinoin

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

Retinoic acid (RA) is known to have several functions that lead to a potent mucosal IgA response. Nevertheless, its exact role in human IgA synthesis has yet to be elucidated. Thus, we investigated the role of RA in promoting IgA isotype switching in human B cells. We found that RA increased IgA production and the expression of germ-line IgA1 and IgA2 transcripts (GLTα1 and GLTα2). This induction occurred alongside an increase in the frequency of IgA1-secreting B cell clones, as assessed by limiting dilution analysis. Under the same conditions, RA did not increase IgM and IgG production. Am80, an agonist of RA receptor α (RARα), increased IgA production. In addition, RA activity was abrogated by LE540, an antagonist of RAR, suggesting that the RAR pathway is involved in RA-induced IgA production. Taken together, these results indicate that RA induces IgA isotype switching mainly through RARα in human B cells.

Topics: B-Lymphocytes; Benzoates; Dibenzazepines; Gene Expression Regulation; Humans; Immunoglobulin A; Immunoglobulin Class Switching; Immunoglobulin G; Immunoglobulin M; Palatine Tonsil; Primary Cell Culture; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; RNA, Messenger; Signal Transduction; Tetrahydronaphthalenes; Transforming Growth Factor beta1; Tretinoin

For patients with relapsed acute promyelocytic leukemia (APL), all-trans retinoic acid-based salvage regimens can achieve second complete remission (CR2), but the optimal post-remission strategy for APL patients after CR2 remains unclear. Hematopoietic stem cell transplantation (HSCT) during CR2 might be effective, but data on the role of HSCT for APL patients after CR2 are limited in Japan. We retrospectively analyzed outcomes for 57 relapsed APL patients who achieved CR2 in the JALSG APL97 study. Of those, six received autologous (auto)-HSCT, 21 received allogeneic (allo)-HSCT, and 30 received various regimens other than HSCT. The 5-year event-free survival (EFS) rate, overall survival (OS) rate and cumulative incidence of relapse (CIR) were 50.7%, 77.4% and 51.0% in the non-HSCT group, 41.7%, 83.3% and 58.3% in the auto-HSCT group and 71.1%, 76.2% and 9.8% in the allo-HSCT group, respectively. Both the EFS rate and CIR were significantly better in the allo-HSCT group than in other groups. Allo-HSCT appears effective in APL patients in CR2, with a low relapse rate beyond a relatively early transplantation-related mortality (19%). Among older patients (age ≥40 years), the 5-year OS was significantly better in the non-HSCT group than in the HSCT group (78.0% vs 40.5%; P = 0.04). Further prospective studies with larger patient numbers are required to confirm the impact of HSCT alone and in combination with arsenic trioxide on outcomes for patients with APL in CR2.

Topics: Adolescent; Adult; Age Factors; Aged; Antineoplastic Agents; Arsenic Trioxide; Arsenicals; Benzoates; Combined Modality Therapy; Disease-Free Survival; Female; Hematopoietic Stem Cell Transplantation; Humans; Japan; Kaplan-Meier Estimate; Leukemia, Promyelocytic, Acute; Male; Middle Aged; Oxides; Recurrence; Retrospective Studies; Salvage Therapy; Tetrahydronaphthalenes; Transplantation Conditioning; Transplantation, Autologous; Transplantation, Homologous; Treatment Outcome; Tretinoin; Young Adult

All-trans retinoic acid (ATRA) is an active metabolite of Vitamin A, it shows protective effects on asthma, including maintains airway epithelial integrity, inhibits asthma effector cells differentiation, modulates immune response, et al. However, the promoting effect of ATRA on Th2 response has restricted the clinical application of ATRA in asthma treatment. ORMDL3 is a candidate gene of childhood onset asthma, and high-transcript of ORMDL3 is associated with the development of asthma. Here we show that ATRA increases ORMDL3 production in vitro via inducing PKA-dependent CREB phosphorylation which in turn binds to the CRE element in promoter region of ORMDL3 and initiates ORMDL3 transcription. This finding is in consistent with the previous reports that ATRA could regulate target genes without the presence of retinoic acid response element (RARE) in promoter region but through other signals such as PKA/CREB. Nevertheless, in the present study, the traditional signal pathway of ATRA, retinoic acid receptor (RAR) signal transduction pathway, indirectly modulated ORMDL3 expression. RAR-α agonist (Am-80) increased ORMDL3 production even though there was no RARE in ORMDL3 promoter, introns or 3'-downstream region. Besides, the signal of RAR might differ from that of ATRA since Am-80 failed to induce CREB activation. In conclusion, our data indicate that ATRA facilitates ORMDL3 production probable through PKA/CREB, and this may be a starting point for more detailed mechanism researches on ATRA and asthma.

Topics: 3' Untranslated Regions; Animals; Asthma; Benzoates; Cell Differentiation; Cell Line, Tumor; Cyclic AMP Response Element-Binding Protein; Cyclic AMP-Dependent Protein Kinases; Epithelial Cells; Gene Expression Regulation; Humans; Introns; Membrane Proteins; Mice; NIH 3T3 Cells; Phosphorylation; Receptors, Retinoic Acid; Response Elements; Retinoic Acid Receptor alpha; Signal Transduction; Tetrahydronaphthalenes; Transcription, Genetic; Tretinoin

Topics: Aminoglycosides; Antibodies, Monoclonal, Humanized; Arsenic Trioxide; Arsenicals; Benzoates; Child; Drug Administration Schedule; Gemtuzumab; Humans; Leukemia, Promyelocytic, Acute; Male; Oxides; Recurrence; Remission Induction; Tetrahydronaphthalenes; Tretinoin

We have recently proposed that retinoic acid receptor (NR1B) is a promising target of neuroprotective therapy for intracerebral hemorrhage, since pretreatment of mice with an NR1B1/NR1B2 agonist Am80 attenuated various pathological and neurological abnormalities associated with the disease. In the present study we further addressed the effects of retinoids as potential therapeutic drugs, using a collagenase-induced model of intracerebral hemorrhage. Daily oral administration of all-trans retinoic acid (ATRA; 5 and 15 mg/kg), a naturally occurring NR1B agonist, from 1 day before collagenase injection significantly inhibited loss of neurons within the hematoma. ATRA in the same treatment regimen also decreased the number of activated microglia/macrophages around the hematoma but did not affect the hematoma volume. ATRA (15 mg/kg) as well as Am80 (5mg/kg) rescued neurons in the central region of hematoma, even when drug administration was started from 6h after induction of intracerebral hemorrhage. However, in this post-treatment regimen, only Am80 significantly decreased the number of activated microglia/macrophages. With regard to neurological deficits, both ATRA (15 mg/kg) and Am80 (5mg/kg) given in the post-treatment regimen improved performance of mice in the beam-walking test and the modified limb-placing test. ATRA and Am80 also significantly attenuated damage of axon tracts as revealed by amyloid precursor protein immunohistochemistry. These results underscore potential therapeutic values of NR1B agonists for intracerebral hemorrhage.

Topics: Animals; Bacterial Proteins; Benzoates; Brain; Cell Count; Cerebral Hemorrhage; Collagenases; Disease Models, Animal; Dose-Response Relationship, Drug; Macrophage Activation; Macrophages; Male; Mice; Mice, Inbred C57BL; Microbial Collagenase; Microglia; Neurons; Neuroprotective Agents; Psychomotor Disorders; Receptors, Retinoic Acid; Retinoids; Tetrahydronaphthalenes; Time Factors; Tretinoin

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: Adult; Aminoglycosides; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Arsenic Trioxide; Arsenicals; Benzoates; Bone Marrow; Bone Neoplasms; Combined Modality Therapy; Doxorubicin; Drug Resistance, Neoplasm; Gemtuzumab; Hematopoietic Stem Cell Transplantation; Humans; Idarubicin; Leukemia, Promyelocytic, Acute; Leukemic Infiltration; Male; Mercaptopurine; Methotrexate; Oxides; Radionuclide Imaging; Remission Induction; Salvage Therapy; Sarcoma, Myeloid; Soft Tissue Neoplasms; Tetrahydronaphthalenes; Tretinoin

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

Topics: Anthracyclines; Antineoplastic Combined Chemotherapy Protocols; Benzoates; Cytarabine; Daunorubicin; Hemorrhage; Humans; Idarubicin; Leukemia, Promyelocytic, Acute; Tetrahydronaphthalenes; Tretinoin

Retinoids including natural vitamin A, its derivatives and synthetic compounds work as transcription factors through the retinoic acid receptors (RAR, RXR). All-trans retinoic acid (ATRA), a family of retinoids, is an internal ligand of RAR and well known as a useful differentiation inducer to treat acute promyelocytic leukemia (APL). ATRA therapy is now established as an initial treatment for APL. Recently, to improve therapeutic potency and reduce adverse effects of ATRA, a novel synthetic selective agonist for RARalpha and beta, Am80, was developed and applied to APL treatment. In this study, we tested whether Am80 was capable of inducing neuronal differentiation in a human neuroblastoma cell line, NH-12 and compared the differentiation effects between Am80 and ATRA. Morphological studies demonstrated that Am80 induced more potent neurite outgrowth and also proved lesser cell toxicity than ATRA. Am80 up-regulated the expression of tropomyosin-related kinase B as well as ATRA. Moreover, Am80 increased the expression of the neuronal marker, growth-associated protein 43. These findings suggest that Am80 induces neuronal differentiation to a greater extent than ATRA and thus may help establishing therapeutic strategies against neuronal degenerative disorders such as Parkinson's disease.

Topics: Antineoplastic Agents; Benzoates; Cell Differentiation; Cell Line, Tumor; GAP-43 Protein; Humans; Neuroblastoma; Neurons; Receptors, Retinoic Acid; Tetrahydronaphthalenes; Tretinoin

The present study investigated the effect of 4[(5,6,7,8-tetrahydro-5,5,8,8,-tetramethyl-2-naphthalenyl)carbamoyl] benzoic acid (Am-80), a synthetic retinoid, on spinal cord injury (SCI) in rats. Treatment with Am-80 (orally and subcutaneously) significantly promoted recovery from SCI-induced motor dysfunction. On day 28 after injury, the lesion cavity was markedly reduced, while the expression of myelin basic protein (MBP; myelin), betaIIItubulin (neuron), and glial fibrillary acidic protein (GFAP; astrocyte) was increased, in comparison with SCI controls. Interestingly, expression of neurotrophin receptor, tyrosine kinase B (TrkB) was over 3-fold higher after Am-80 treatment than in SCI controls. A lot of TrkB-positive cells as well as brain-derived neurotrophic factor (BDNF)-positive ones were observed around the injured site. Am-80 (10 microM) combined with BDNF (100 ng/ml) promoted extensive neurite outgrowth and TrkB gene expression by cultured SH-SY5Y cells, as did all-trans retinoic acid (ATRA). Thymidine incorporation was dramatically suppressed, but there was little effect on cell viability. These findings suggest that Am-80 has the potential to be used for treating neurodegenerative disorders, including SCI. Its efficacy may be partly ascribed to promotion of cell viability and differentiation of neural stem cells through increased TrkB expression.

Topics: Animals; Benzoates; Biomarkers; Blotting, Western; Cell Differentiation; Cell Line, Tumor; Female; Hindlimb; Humans; Keratolytic Agents; Locomotion; Movement Disorders; Nerve Tissue Proteins; Neurons; Rats; Rats, Sprague-Dawley; Retinoids; Spinal Cord Injuries; Tetrahydronaphthalenes; Tretinoin

Recent evidence suggests that interleukin-17-producing CD4(+) T cells (Th17 cells) are the dominant pathogenic cellular component in autoimmune inflammatory diseases, including multiple sclerosis. It has recently been demonstrated that all-trans retinoic acid can suppress Th17 differentiation and promote the generation of Foxp3(+) regulatory T cells via retinoic acid receptor signals. Here, we investigated the effects of AM80, a synthetic retinoid with enhanced biological properties to all-trans retinoic acid, on Th17 differentiation and function and evaluated its therapeutic potential in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. AM80 treatment was more effective than all-trans retinoic acid in inhibiting Th17 differentiation in vitro. Oral administration of AM80 was protective for the early development of EAE and the down-modulation of Th17 differentiation and effector functions in vivo. Moreover, AM80 inhibited interleukin-17 production by splenic memory T cells, in vitro-differentiated Th17 cells, and central nervous system-infiltrating effector T cells. Accordingly, AM80 was effective when administered therapeutically after the onset of EAE. Continuous AM80 treatment, however, was ineffective at inhibiting late EAE symptoms despite the maintained suppression of RORgammat and interleukin-17 expression levels by central nervous system-infiltrating T cells. We reveal that continuous AM80 treatment also led to the suppression of interleukin-10 production by a distinct T cell subset that expressed both Foxp3 and RORgammat. These findings suggest that retinoid signaling regulates both inflammatory Th17 cells and Th17-like regulatory cells.

Topics: Animals; Benzoates; Cell Differentiation; Cytokines; Encephalomyelitis, Autoimmune, Experimental; Enzyme-Linked Immunosorbent Assay; Female; Flow Cytometry; Interleukin-17; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Retinoids; Reverse Transcriptase Polymerase Chain Reaction; T-Lymphocyte Subsets; T-Lymphocytes, Regulatory; Tetrahydronaphthalenes; Tretinoin

The mechanisms underlying trafficking and membrane targeting of EAAC1, the rodent counterpart of the human EAAT3 carrier for anionic amino acids, are well characterized. In contrast, much less is known on the regulation of Slc1a1, the gene that encodes for the transporter. We have recently found that all-trans retinoic acid (ATRA) stimulates EAAC1 expression and anionic amino acid transport in C6 rat glioma cells. We report here that the ATRA effect on EAAC1 activity was inhibited by the specific RAR antagonist LE540 and mimicked by Am80, a RAR agonist, but not by the RXR agonist HX630. Moreover, the ATRA-dependent induction of Slc1a1 mRNA required the synthesis of a protein intermediate and was not associated with changes in the messenger half-life. ATRA treatment induced the expression of both Rarb mRNA and RARbeta protein several hours before the induction of Slc1a1, while the mRNA for RFX1, a transcription factor recently involved in Slc1a1 transcription, was unchanged. In addition, Rarb silencing markedly inhibited the ATRA-dependent increase of both Rarb and Slc1a1 mRNAs. We conclude that in C6 glioma cells the induction of Slc1a1 by ATRA requires the synthesis of RARbeta, suggesting that the receptor is involved in the regulation of the transporter gene.

Topics: Animals; Benzoates; Cell Line, Tumor; Dibenzazepines; Excitatory Amino Acid Transporter 3; Gene Silencing; Rats; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; RNA, Messenger; Tetrahydronaphthalenes; Tretinoin

Tamibarotene (TM411) is a synthetic retinoic acid receptor-alpha/-beta selective retinoid that is chemically more stable than all-trans retinoic acid. This study was designed to evaluate the activity of TM411 in multiple myeloma (MM) and the effects of TM411 combined with a glucocorticoid (GC). In vitro, five human myeloma cells were treated with TM411 alone, GC alone, or TM411 + GC. Cell survival was analyzed by the tetrazolium dye assay and the Hoechst 33342/propidium iodide double-staining method. The effect of TM411 + GC was assessed by the isobologram method. In vivo, the growth-inhibitory effects of the drugs on RPMI-8226 cell xenografts established in SCID mice were examined. The effects of the agents on IL-6-mediated signaling pathways were also analyzed by Western blotting. TM411 was 2- to 10-fold more potent, in terms of its growth-inhibitory effect, than all-trans retinoic acid. The combination of TM411 and GC was found to show a markedly synergistic interaction. While increased expressions of the IL-6 receptor, phosphorylated MAPK, and Akt were observed after exposure to GC, TM411 attenuated this increase in the expressions, suggesting that such modification of the effect of GC by TM411 might be the possible mechanism underlying the synergistic interaction. Furthermore, TM411 + GC showed a supra-additive inhibitory effect in a xenograft model as compared with TM411 or GC alone. These results imply that the combination of TM411 + GC might be highly effective against MM, and suggest the need for clinical evaluation of TM411 + GC for the treatment of MM.

Topics: Animals; Antineoplastic Agents; Benzoates; Cell Division; Cell Line, Tumor; Cell Survival; Drug Synergism; Female; Glucocorticoids; Humans; Mice; Mice, SCID; Multiple Myeloma; Retinoids; Tetrahydronaphthalenes; Tretinoin

25-Hydroxyvitamin D(3)-24-hydroxylase (24-hydroxylase) is an important inactivating enzyme and its expression is induced by 25-hydroxyvitamin D3 (25OHD3) and 1alpha,25-dihydroxyvitamin D3 (1alpha,25-(OH)2D3) through action of heterodimers of vitamin D receptor (VDR) and retinoid X receptor (RXR). RXRs also act as heterodimer partners for retinoic acid receptors (RARs), mediating the action of all-trans-retinoic acid (ATRA). Prostate stroma plays a crucial role in prostate cancer development and benign prostatic hyperplasia. We demonstrate here that ATRA markedly reduced the expression of 24-hydroxylase mRNA induced by 25OHD3 and 1alpha,25-(OH)2D3 in human prostatic stromal cells P29SN and P32S but not in epithelial cells PrEC or cancer cells LNCaP. By using transfection and RAR-selective ligands, we found that the inhibitory effect of ATRA on 24-hydroxylase expression in stromal cells was mediated by RARalpha but not by RARbeta. Moreover, the ATRA-induced expression of RARbeta was also mediated by RARalpha. The combined treatment of 1alpha,25-(OH)2D3 and RARalpha agonist Am80 at 10 nM exhibited strong growth-inhibitory effect whereas either alone had no effect. Our data suggest that ATRA suppresses 24-hydroxylase expression through RARalpha-dependent signaling pathway and can enhance vitamin D action in suppression of cell growth.

Topics: Benzoates; Calcitriol; Cell Line; Cell Line, Tumor; Cells, Cultured; Dibenzazepines; Epithelial Cells; Gene Expression Regulation; Humans; Male; Prostate; Prostatic Neoplasms; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Retinoid X Receptors; Retinoids; Steroid Hydroxylases; Tetrahydronaphthalenes; Transfection; Tretinoin; Vitamin D3 24-Hydroxylase

All-trans retinoic acid (ATRA) and Am80 are natural and synthetic derivatives of Vitamin A and have been used in the fields of oncology and dermatology for years. Their action was considered to be achieved mainly through binding to nuclear hormone receptors, retinoic acid receptors (RARs), although they have been observed to have different biological effects. For example, the two compounds have similar effects on differentiation but different effects on proliferation in human promyelocytic leukemia cell line HL-60 cells. To elucidate the genes responsible for this and other differences, we attempted for the first time to determine the genes whose expressions were differentially modulated during the time course of HL-60 cell differentiation by ATRA and Am80 treatment up to 72h utilizing DNA microarray and clustering analyses. As a result, the expressions of 204 genes were found to be modulated differentially by ATRA and Am80. Among them, we focused on two components of the PI3-kinase/Akt signal transduction pathway, phosphoinositide-3-kinase, beta-catalytic subunit and ribosomal protein S6 kinase polypeptide 1, which are related to the regulation of cell proliferation and apoptosis. Their expressions were specifically suppressed by ATRA, which coincided with the suppressive effects of ATRA on the HL-60 cell proliferation. Moreover, PI3-kinase inhibitors suppressed the proliferation of Am80-treated cells to the same extent as ATRA did. These results indicated that these gene products play a role in HL-60 cell growth suppression during the late stage of differentiation. The complete data and a list of the genes are available at .

Topics: Antineoplastic Agents; Benzoates; Carrier Proteins; Cell Differentiation; Gene Expression Profiling; HL-60 Cells; Humans; Intracellular Signaling Peptides and Proteins; Oligonucleotide Array Sequence Analysis; Phosphatidylinositol 3-Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6 Kinases; Tetrahydronaphthalenes; Tretinoin; Tumor Cells, Cultured

3,5,3'-Triiodo-L-thyronine (T3) potentiates apoptosis during the all-trans-retinoic acid-induced differentiation of promyeloleukemic HL-60 cells. We examined whether the retinoid receptor-specific thyroid hormone action is present during differentiation of HL-60 cells in this study. We used two distinct retinoid receptor agonists. T3 potentiates G1 arrest induced by Am80, a retinoic acid receptor (RAR)-specific agonist, but had no effect on G1 arrest induced by HX600, a retinoid x receptor (RXR)-specific agonist. Am80 alone induces the apoptosis, and T3 enhances it. Although HX600 alone fails to increase the apoptotic fraction, T3 enables the compounds to induce apoptosis. Am80-induced expression of CD11b, a marker for the differentiation, is enhanced by T3. However, T3 or HX600 or both do not affect the expression of CD11b. T3 does not alter the amount of mRNAs of various members of the bcl-2 family. T3, however, enhances the Am80-induced expression of bfl-1 and suppression of bcl-2. In contrast, T3 does not alter either bfl-1 and bcl-2 expression in the presence of HX600. Our observations suggest that cooperative action of T3 with an RXR-specific ligand is different from that with an RAR ligand in cellular apoptotic regulation and that thyroid hormone may be available as a chemotherapeutic agent in acute leukemia.

Topics: Apoptosis; Benzoates; CD11 Antigens; Cell Division; Dibenzazepines; Drug Synergism; Flow Cytometry; Gene Expression; HL-60 Cells; Humans; Ligands; Proto-Oncogene Proteins c-bcl-2; Receptors, Retinoic Acid; Retinoid X Receptors; RNA, Messenger; Tetrahydronaphthalenes; Transcription Factors; Tretinoin; Triiodothyronine

In human HL-60 promyelocytic leukemia cells, diazepinylbenzoic acid derivatives can exhibit either antagonistic or synergistic effects on the differentiation-inducing activities of natural or synthetic retinoids, the activity depending largely on the nature of the substituents on the diazepine ring. Thus, a benzolog of the retinoid antagonist LE135 (6), 4-(13H-10,11,12,13-tetrahydro-10, 10,13,13,15-pentamethyldinaphtho[2,3-b][1,2-e]diazepin-7-yl) benzoic acid (LE540, 17), exhibits a 1 order of magnitude higher antagonistic potential than the parental LE135 (6). In contrast, 4-[5H-2,3-(2,5-dimethyl-2,5-hexano)-5-methyldibenzo[b,e] [1,4]diazepin-11-yl]-benzoic acid (HX600, 7), a structural isomer of the antagonistic LE135 (6), enhanced HL-60 cell differentiation induced by RAR agonists, such as Am80 (2). This synergistic effect was further increased for a thiazepine, HX630 (29), and an azepine derivative, HX640 (30); both synergized with Am80 (2) more potently than HX600 (7). Notably, the negative and positive effects of the azepine derivatives on retinoidal actions can be related to their RAR-antagonistic and RXR-agonistic properties, respectively, in the context of the RAR-RXR heterodimer.

Topics: Azepines; Benzoates; Binding, Competitive; Cell Differentiation; Dibenzazepines; Dimerization; Drug Synergism; HL-60 Cells; Humans; Molecular Structure; Protein Binding; Receptors, Retinoic Acid; Retinoid X Receptors; Retinoids; Tetrahydronaphthalenes; Transcription Factors

We have recently established a human osteoblastic cell line (SV-HFO) in a culture system, in which the cells are mineralized by treatment with dexamethasone (Dex). Using this system, we examined the effects of all trans-retinoic acid (RA) on the mineralization of the cells. RA inhibited the mineralization, coincident with the inhibition of alkaline phosphatase (ALP). On the other hand, RA induced osteocalcin secretion and had no effect on the expression of the other osteoblastic markers such as type I collagen and osteonectin. To further clarify the mechanism of inhibition of mineralization by RA, we used the retinoic acid receptor (RAR) alpha-selective (Am80), beta-selective (CD2019) and gamma-selective (CD437) agonists instead of RA. RAR alpha- and RAR beta-selective agonists inhibited the mineralization and ALP activity of the cells, while the RAR gamma-selective agonist had no such effects. On the other hand, the RAR gamma-selective agonist induced osteocalcin secretion, but RAR alpha- and RAR beta-selective agonists had no effect on osteocalcin secretion. These results suggested that the inhibitory effect of RA on the mineralization of human osteoblasts is mediated by the activation of RAR alpha and/or RAR beta and that RAR gamma preferentially regulates the expression of osteocalcin without influence on mineralization.

Topics: Alkaline Phosphatase; Benzoates; Biomarkers; Calcification, Physiologic; Cell Line; Dexamethasone; Enzyme Inhibitors; Humans; Naphthalenes; Osteoblasts; Osteocalcin; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Retinoic Acid Receptor gamma; Retinoids; Teratogens; Tetrahydronaphthalenes; Tretinoin

Two patients with relapsed acute promyelocytic leukaemia previously treated with all-trans retinoic acid (ATRA), were treated with a new synthetic retinoid, Am-80. In both patients pancytopenia gradually resolved without an increase in leukaemic cells, and differentiation of leukaemic cells was observed morphologically in bone marrow. Without the use of anti-leukaemic agents, both cases achieved complete remission (CR) on days 52 and 38 of treatment, respectively. On the day of CR, PML gene rearrangement and the t(15;17) translocation disappeared, though PML-RAR alpha chimaeric messenger RNA was still detected by reverse transcriptase polymerase chain reaction. Both patients then received conventional chemotherapy for consolidation of CR. These clinical experiences suggest that Am-80 may be an active agent for APL patients who have relapsed from ATRA-induced remission.

Topics: Adult; Benzoates; Female; Humans; Leukemia, Promyelocytic, Acute; Middle Aged; Recurrence; Remission Induction; Tetrahydronaphthalenes; Tretinoin

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

Several candidate retinoid antagonists were designed on the basis of the ligand superfamily concept and synthesized. Retinoidal activities of these benzimidazole and benzodiazepine derivatives were examined by assay of differentiation-inducing activity on human promyelocytic leukemia cell line HL-60. The parent benzimidazole derivative, 4-(5,6,7,8-tetrahydro-5,5,8,8- tetramethylnaphth-[2,3-d]imidazol-2-yl)benzoic acid (7a), and related compounds with a small alkyl group instead of the hydrogen on the nitrogen (1N) atom of the imidazole ring exhibited retinoidal activity, and the potency strongly depended on the bulkiness of the substituent. The compounds having a phenyl or benzyl group on the nitrogen lacked differentiation-inducing activity on HL-60 cells and acted as antagonists to the potent retinoid 4-[(5,6,7,8-tetrahydro-5,5,8,8- tetramethyl-2-naphthalenyl)carbamoyl]benzoic acid (Am80). Among the compounds possessing a seven-membered heterocyclic ring as a linking group, 4-(5H-7,8,9,10-tetrahydro-5,7,7,10,10- pentamethylbenzo[e]- naphtho[2,3-b][1,4]diazepin-13-yl)benzoic acid (16) also exhibited the antagonistic activity. The binding abilities of these compounds to retinoic acid receptors alpha and beta were consistent with their potency for the inhibition of HL-60 cell differentiation induced by the retinoid Am80.

Topics: Benzimidazoles; Benzoates; Benzodiazepines; Cell Differentiation; Cell Line; Drug Design; Humans; Receptors, Retinoic Acid; Retinoids; Structure-Activity Relationship; Tetrahydronaphthalenes; Tumor Cells, Cultured

Retinoids, especially all-trans retinoic acid (RA), have been shown to inhibit the differentiation of preadipose cells. It is important to human health, especially to obesity, that the regulatory system for the differentiation of adipocytes is well defined. Previously, we have shown that retinoic acid receptor (RAR) gamma 2 gene expression is up-regulated by RA in 3T3-L1 preadipose cells. In this study, the RAR system was dissected and the RA-regulated function in 3T3-L1 cells was assigned to one given receptor. We used three synthetic retinoids; (1) Ro 41-5253, a selective RAR alpha antagonist, (2) Ch 55, an RAR alpha, beta and gamma agonist, and (3) Am 80, an RAR alpha and beta agonist, which has less affinity to RAR gamma. Ro 41-5253 reverted RA-induced inhibition of the differentiation of 3T3-L1 cells. However, there was no significant reversion in RA-induced RAR gamma mRNA level by treatment with Ro 41-5253. In the case of RAR agonists, both Am 80 and Ch 55 strongly inhibited the differentiation of 3T3-L1 cells. However, Am 80 weakly increased RAR gamma mRNA content less than did Ch 55. These findings suggest, that RAR alpha is involved in the prevention of adipose differentiation by RA in 3T3-L1 cells. Moreover, there seems no causal relationship between the prevention of adipose differentiation by RA and the up-regulation of RAR gamma 2 gene expression by RA in 3T3-L1 cells. We have shown the functional heterogeneity of RA action through different RARs in 3T3-L1 cells.

Topics: 3T3 Cells; Adipocytes; Animals; Benzoates; Cell Differentiation; Chalcone; Chalcones; Chromans; Mice; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Retinoids; Tetrahydronaphthalenes; Tretinoin

all-trans-Retinoic acid (RA) is a potent inducer in vitro of the differentiation of the human acute myeloid leukemia cell line HL60. A mechanism for RA-induced differentiation of HL60 cells may involve retinoylation (RA acylation) which is a post-translational modification of proteins occurring in many eukaryotic cell lines. Here, we found that differentiation by the synthetic retinoid (E)4-[3-(3,5-di-tert-butylphenyl)-3-oxo-1-propenyl]-benzoic acid (Ch55) was dose-dependent in serum-free medium. The synthetic retinoid 4(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenylcarbamoyl) benzoic acid (Am80) did not induce differentiation. Ch55 bound covalently to proteins of HL60 cells. In contrast, covalent binding of Am80 to HL60 proteins was much lower. Two-dimensional gel electrophoresis patterns of proteins labeled covalently by RA and Ch55 were different with few proteins labeled by both retinoids. The level of retinoylation was increased by Am80 and combinations of RA with either Ch55 or Am80 synergistically induced differentiation of HL60 cells. These results suggest that covalent modification of proteins by a retinoid may play a role in inducing differentiation of HL60 cells. In addition, the synergy seen with combinations of RA and either Ch55 or Am80 suggests that some synthetic retinoids may be active because they displace RA from intracellular sites or because they inhibit RA catabolism.

Topics: Benzoates; Cell Differentiation; Chalcone; Chalcones; Drug Synergism; Electrophoresis, Gel, Two-Dimensional; Humans; Leukemia, Promyelocytic, Acute; Neoplasm Proteins; Protein Binding; Tetrahydronaphthalenes; Tretinoin; Tumor Cells, Cultured

RCJ C 5.18 (C 5.18) is a chondrogenic clonal cell line which, under standard culture conditions, develops chondroblastic features including the production of a cartilagenous matrix. Retinoic acid (RA) is known to inhibit the chondrogenic differentiation of C 5.18 cells and this may parallel the teratogenic effects of retinoids in vivo; however, the question as to which of the 3 retinoic acid receptors (RAR alpha, beta, gamma) or the 3 retinoid X receptors (RXR alpha, beta, gamma) mediate this RA-induced inhibition remains unanswered. We tested several retinoids with different receptor binding characteristics. Cartilage formation in C 5.18 cultures was evaluated by counting the number of cartilage nodules formed, and by quantitating the glycosaminoglycan content of the cultures using alcian blue staining. All of the retinoids prevented cartilage formation in a dose-dependent manner. Treatment with the retinoids did not affect cell number, thereby ruling out any toxic effects. RA, which binds to all 3 RARs with similar affinity, produced a 50% inhibition (IC50) of cartilage formation at 4 x 10(-10) M. We also tested Ch55, which also binds to all 3 RARs, but with higher affinity than RA. This compound was approximately 10 times more potent than RA (IC50 2 x 10(-11) M). 9-cis RA, which binds to the 3 RARs with affinities similar to RA and also binds to the 3 RXRs, was less active (IC50 8 x 10(-9) M), suggesting that RXR binding interferes with the inhibitory effect of ligand-activated RARs. 9-cis retinal, for which the binding characteristics are unknown, had the same effect as 9-cis RA.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Benzoates; Cartilage; Cell Differentiation; Cell Line; Chalcone; Chalcones; Dose-Response Relationship, Drug; Glycosaminoglycans; Rats; Receptors, Cytoplasmic and Nuclear; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Retinoic Acid Receptor gamma; Retinoid X Receptors; Retinoids; Teratogens; Tetrahydronaphthalenes; Transcription Factors; Tretinoin