PURPOSE: The growth regulatory effect of retinoid derivatives could be mediated by the transcriptional inactivation of AP-1 oncogenic transcription factor. By using ovarian cancer cell lines we were to investigate the cross-regulation mechanism between retinoids and AP-1. MATERIALS AND METHODS: Cell proliferation assays were performed in 4 ovarian cancer cells (A2774, PA-1, OVCAR-3, SKOV-3) by increasing the concentrations of all-trans retinoic acid (ATRA), 9-cis retinoic acid (9RA), 13-cis RA (13RA), 4-hydroxyphenyl retinamide (4-HPR). Transient transfection and CAT ELISA were done to determine the selective activity of each retinoid on the RAR (alpha, beta, gamma), RXR (alpha, beta, gamma). and the negative activity on AP-1 (c-Jun). RESULTS: Antiproliferative effect of 4-HPR (IC50; 0.7~2.7 micrometer) was more potent than those of other retinoid derivatives (IC50; 2.7~9.0 micrometer). To assess the anticancer mechanism, we examined the effect of 4-HPR on the transriptional activity of retinoic acid receptors (RAR/RXR) and of c-jun. Contrary to other retinoid derivatives that are active for RAR and RXR with some different levels, 4-HPR showed weak activity only for RARgamma. However, 4-HPR exerted the strongest suppression on AP-1 (c-Jun) activity. CONCLUSION: Based on our results showing much 4-HPR's potent antiproliferative activity coupled with the most effectively inhibiting activity on AP-1 and minimum activity on RA receptor (selective for RARgamma) than other retinoid derivatives, we suggest that 4-HPR may be a novel, and very effective anticancer drugs for ovarian cancer.
Animals ; Cats ; Cell Line ; Cell Proliferation ; Enzyme-Linked Immunosorbent Assay ; Fenretinide ; Ovarian Neoplasms* ; Receptors, Retinoic Acid ; Retinoid X Receptors ; Retinoids ; Transcription Factor AP-1* ; Transcription Factors ; Transfection ; Tretinoin

Extracellular Matrix ; physiology ; Humans ; Lipid Peroxidation ; Liver ; pathology ; Liver Cirrhosis ; etiology ; Receptors, Retinoic Acid ; physiology ; Retinoid X Receptors ; Risk Factors ; Sodium-Hydrogen Exchangers ; physiology ; Transcription Factors ; physiology

Apoptosis ; Caspase 3 ; Caspases ; physiology ; Cell Line, Tumor ; Cell Proliferation ; Humans ; Isotretinoin ; pharmacology ; Melanoma ; pathology ; Receptors, Retinoic Acid ; physiology ; Retinoid X Receptors ; physiology ; Tretinoin ; pharmacology

PURPOSE: Retinoids (RA), a group of vitamin A derivatives, is known to be important for regulation of normal cellular growth and differentiation. RA treatment of various cancers resulted in cell growth inhibition and apoptosis. Therefore, the chemotherapeutic and chemopreventative activities of various types of tumor have been examined. Biological actions of RA are mediated through nuclear receptors, including the retinoic acid receptors (RARs) and retinoid X receptors (RXRs). In this study, we examined the effect of all-trans-retinoic acid (atRA) as an anticancer drug-sensitiser in cancer cell lines and in its drug- resistant cancer cell lines MATERIALS AND METGODS: Cells were maintained by RPMI 1640 medium containing 10% fetal bovine serum. Cells were treated with 1 micro M atRA for 48 h, then with the desired concentration of anticancer drug for 24 h. Cell viability was measured spectrophotometrically at 540 nm using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay. Western blot analyses were performed with the desired antibodies. RESULTS: We investigated if pre-treatment with atRA enhanced the drug-sensitivity of various cancer cell lines to either 5-fluorouracil, adriamycin, or cisplatin. 5-FU (SNU638-F2) and CDDP-resistant cell (SNU638-Cis) lines, from a Korean gastric cancer cell line (SNU638) and the ADR-resistant cells (AD600) was established from a colon cancer cell line (SW620). Treatment of each cell line, with 1 micro M atRA, prior to drug exposure resulted in enhanced cell death in these cell lines. Furthermore, the effect of atRA on growth inhibition, in each drug-resistant cell line, was more obvious than in their parent cell lines. Increased activity of Transglutaminase II (TgaseII) and cleavage of Poly (ADP-ribose) polymerase (PARP) were also observed (western blot analysis CONCLUSION: Based on our data, we suggest that atRA enhances anticancer drug-induced cell death and reverses the drug-sensitivity of the drug-resistant cancer cell lines.
Antibodies ; Apoptosis ; Blotting, Western ; Cell Death* ; Cell Line* ; Cell Survival ; Cisplatin ; Colonic Neoplasms ; Doxorubicin ; Fluorouracil ; Humans ; Parents ; Receptors, Cytoplasmic and Nuclear ; Receptors, Retinoic Acid ; Retinoid X Receptors ; Retinoids ; Stomach Neoplasms ; Tretinoin* ; Vitamin A

OBJECTIVETo study the effect of retinoid kappa receptor alpha (RXRalpha) transfection plus treatment with the RXRalpha ligand, 9-cis-RA, on the proliferation and phenotype of platelet-derived growth factor (PDGF) activated hepatic stellate cells (HSCs).

METHODSPDGF activated rat hepatic stellate cells were transfected with eukaryotic expression vector pcDNA3.1- human RXRalpha, and confirmed by Western blot. Proliferation of transfected HSC was assayed by bromodeoxyuridine (BrdU) incorporation as well as MTT, and the phenotype (alpha-smooth muscle actin, desmin) was observed by immunocytochemistry with image analysis.

RESULTSTransfection of the RXRalpha gene and treatment with ligand 9-cis-RA of PDGF-activated HSCs extended the increased expression of RXRalpha protein for at least 168 hours. Cell proliferation and expressions of alpha- smooth muscle actin (alpha-SMA) and desmin were blocked, compared with groups of sham-transfected, PDGF-activated, no transfection, no ligand treatment, and irrelevant ligand treated HSCs.

CONCLUSIONTransfection with the RXRalpha gene followed by 9-cis-RA ligand treatment will inhibit the proliferation and reverse the phenotype of activated HSC.

Animals ; Cell Division ; Cells, Cultured ; Liver ; cytology ; Liver Cirrhosis ; etiology ; Male ; Phenotype ; Platelet-Derived Growth Factor ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Retinoic Acid ; genetics ; physiology ; Retinoid X Receptors ; Transcription Factors ; genetics ; physiology ; Transfection

OBJECTIVETo screen the protein interacting with retinoic acid receptor variant protein (RAR alpha-V) via the yeast two-hybrid technique (YTHT) and to find out the targets protein and study its biological function.

METHODSThe bait vector of pGBKT7-RAR alpha-V was constructed for screening proteins interacting with RAR alpha-V in K562 cell cDNA expression library via YTHT. The protein-protein interaction was confirmed with re-transformation in yeast and GST pull-down in vitro.

RESULTSThe bait vector was successfully constructed without toxicity, leakage and self-activation. Sixteen proteins were screened by YTHT and eight positive clones were identified by re-transformation in yeast. The interaction between RAR alpha-V and JTV-1 was confirmed by GST pull-down in vitro.

CONCLUSIONSThere are some kinds of proteins interacting with RAR alpha-V in cell. The biological dysfunction caused by certain protein-protein interaction may be involved in the pathogenesis of leukemia.

Gene Library ; Humans ; K562 Cells ; Protein Interaction Mapping ; Receptors, Retinoic Acid ; metabolism ; Retinoic Acid Receptor alpha ; Two-Hybrid System Techniques

OBJECTIVETo approach the effects on induction of differentiation of Tca8113 cells affected by abscisic acid.

METHODSThe changes of surface differentiation markers, cell configuration, restrain of cell growth and the expression of Caspase-3 mRNA were examined by using inverted-phase contrast microscope, immunohistochemistry (IHC) and in situ hybridization in vitro. The dependablity between the surface differentiation markers and Caspase-3 mRNA was analysed.

RESULTSThe restraint of cell growth in ABA groups was higher than that of the control group (P<0.05). There was a trend that the tumor cell had transformed the normal cell. Furthermore, the time-dosage dependent relationship existed in the inhibition rate of tumor cells. The results showed that the expressions of Involucrin protein, retinoic acid receptor beta (RARbeta) and Caspase-3 mRNA in experimental group had been higher than that of control group. There was a significance between the different concentration experimental groups at 24 h (P<0.05). Moreover, the positive correlation existed among the Involucrin, RARbeta and Caspase-3 mRNA at the time of 12 hour and 24 hour (P<0.05).

CONCLUSIONThe possible mechanism is that abscisic acid acted on the tumor cell and raised the level of RARbeta gene through combining the correlative receptors so that increased the expression of Involucrin protein and promoted the activity of Caspase-3 and resulted in apoptosis of tumor cell.

Abscisic Acid ; Apoptosis ; Cell Differentiation ; Cell Division ; Cell Proliferation ; In Vitro Techniques ; RNA, Messenger ; Receptors, Retinoic Acid

OBJECTIVETo explore the effects of TBLR1-RAR&alpha; on the differentiation induction of leukemia cell line K562 cells into erythroid lineage and to investigate its related mechanisms.

METHODSTet-Off inducible system was used to construct the conditional expression vector of TBLR1-RAR&alpha; fusion gene by cloning the TBLR1-RAR&alpha; fragment into lentivirus vector pLVX-Tight-Puro, the expression of TBLR1-RAR&alpha; fusion gene was induced by doxycycline (Dox). Then, K562 cells were transfected with lentivirus pLVX-Tight-Puro-TBLR1-RAR&alpha;-flag, and the expression of fusion proteins was verified by Western blot. After treatment of K562 with all-trans retinoid acid (ATRA), real time RT-PCR was performed to test the expression of erythroid differentiation-related CD71 and &alpha;, ε, &gamma;-globins gene. Flow cytometry was used also to analyze the expression of erythroid differentiation markers CD71 and CD235a. Benzidine staining was used to detect the production of hemoglobin in K562 cells.

RESULTSqRT-RCR showed that ATRA could increase the expression level of CD71 and &alpha;, ε, &gamma;-globin genes when TBLR1-RAR&alpha; was expressed. After treatment of ATRA, the proportion of CD71(+) cells detected by the flow cytometry also increased. Benzidine staining showed that ATRA could induce hemoglobin production in K562 cells with TBLR1-RAR&alpha; fusion gene expression.

CONCLUSIONThe expression of TBLR1-RAR&alpha; fusion gene contribute to ATRA-inducing differentiation of K562 cells into erythroid lineage.

Cell Differentiation ; Erythrocytes ; Hemoglobins ; Humans ; K562 Cells ; Nuclear Proteins ; Receptors, Cytoplasmic and Nuclear ; Receptors, Retinoic Acid ; Repressor Proteins ; Retinoic Acid Receptor alpha ; gamma-Globins

Endogenously eliminating the hematoma is a favorable strategy in addressing intracerebral hemorrhage (ICH). This study sought to determine the role of retinoid X receptor-α (RXR-α) in the context of hematoma absorption after ICH. Our results showed that pharmacologically activating RXR-α with bexarotene significantly accelerated hematoma clearance and alleviated neurological dysfunction after ICH. RXR-α was expressed in microglia/macrophages, neurons, and astrocytes. Mechanistically, bexarotene promoted the nuclear translocation of RXR-α and PPAR-γ, as well as reducing neuroinflammation by modulating microglia/macrophage reprograming from the M1 into the M2 phenotype. Furthermore, all the beneficial effects of RXR-α in ICH were reversed by the PPAR-γ inhibitor GW9662. In conclusion, the pharmacological activation of RXR-α confers robust neuroprotection against ICH by accelerating hematoma clearance and repolarizing microglia/macrophages towards the M2 phenotype through PPAR-γ-related mechanisms. Our data support the notion that RXR-α might be a promising therapeutic target for ICH.
Anilides/pharmacology* ; Cerebral Hemorrhage/drug therapy* ; Hematoma/drug therapy* ; Humans ; Macrophages ; Microglia ; Neuroprotection ; PPAR gamma ; Retinoid X Receptor alpha

The growth inhibitory effects of four retinoic acid (RA) derivatives, 9-cis RA, 13-cis RA, N-(4-hydroxyphenyl) retinamide (4-HPR), and all-trans retinoic acid (ATRA) were compared. In addition, the effects of various combinations of these four agents were examined on non-small cell lung carcinoma (NSCLC) cell-lines, and on the expressions of retinoic acid receptors (RARs) and retinoid X receptors (RXRs) on these cells. At the clinically achievable concentration of 1 micrometer, only 4-HPR inhibited the growths of H1299 and H460 cells-lines. However, retinoic acid receptor beta(RAR beta) expression was up-regulated on H460 and H1299 cells treated with 1 micrometer of ATRA, 13-cis RA, or 9-cis RA. All NSCLC cell lines showed growth inhibition when exposed sequentially to 1 micrometer ATRA and 0.1 micrometer 4-HPR. In particular, sequential treatment with 1 micrometer ATRA or 13-cis RA and 4-HPR markedly inhibited H1703 cell growth; these cells exhibited no basal RAR beta expression and were refractory to 4-HPR. However, in NSCLC cell lines that expressed RAR beta, the expressional levels of RAR beta were up-regulated by ATRA alone and by sequential treatment with ATRA and 4-HPR. 4-HPR was found to be the most active of the four agents in terms of NSCLC growth-inhibition. Moreover, sequential treatments with ATRA or 13-cis RA followed by 4-HPR were found to have synergistic growth-inhibitory effects and to regulate RAR expression.
Base Sequence ; Carcinoma, Non-Small-Cell Lung/*drug therapy/genetics/metabolism ; Cell Line, Tumor ; DNA Primers/genetics ; Drug Therapy, Combination ; Fenretinide/administration & dosage ; Gene Expression/drug effects ; Humans ; Isotretinoin/administration & dosage ; Lung Neoplasms/*drug therapy/genetics/metabolism ; Receptors, Retinoic Acid/genetics ; Retinoid X Receptors/genetics ; Tretinoin/administration & dosage/*analogs & derivatives