The relationship between cisplatin resistance and histone deacetylase isoform overexpression in epithelial ovarian cancer cell lines / 부인종양

OBJECTIVE: To investigate the relationship between cisplatin resistance and histone deacetylase (HDAC) isoform overexpression in ovarian cancer cell lines. METHODS: Expression of four HDAC isoforms (HDAC 1, 2, 3, and 4) in two ovarian cancer cell lines, SKOV3 and OVCAR3, exposed to various concentrations of cisplatin was examined by western blot analyses. Cells were transfected with plasmid DNA of each HDAC. The overexpression of protein and mRNA of each HDAC was confirmed by western blot and reverse transcriptase-polymerase chain reaction analyses, respectively. The cell viability of the SKOV3 and OVCAR3 cells transfected with HDAC plasmid DNA was measured using the cell counting kit-8 assay after treatment with cisplatin. RESULTS: The 50% inhibitory concentration of the SKOV3 and OVCAR3 cells can be determined 15-24 hours after treatment with 15 microg/mL cisplatin. The expression level of acetylated histone 3 protein in SKOV3 cells increased after exposure to cisplatin. Compared with control cells at 24 hours after cisplatin exposure, the viability of SKOV3 cells overexpressing HDAC 1 and 3 increased by 15% and 13% (p<0.05), respectively. On the other hand, OVCAR3 cells that overexpressed HDAC 2 and 4 exhibited increased cell viability by 23% and 20% (p<0.05), respectively, compared with control cells 24 hours after exposure to cisplatin. CONCLUSION: In SKOV3 and OVCAR3 epithelial ovarian cancer cell lines, the correlation between HDAC overexpression and cisplatin resistance was confirmed. However, the specific HDAC isoform associated with resistance to cisplatin varied depending on the ovarian cancer cell line. These results may suggest that each HDAC isoform conveys cisplatin resistance via different mechanisms.

Apoptosis-related mRNA expression profiles of ovarian cancer cell lines following cisplatin treatment / 부인종양

OBJECTIVE: The aim of this study was to identify apoptosis-related genes of ovarian cancer cell lines following cisplatin treatment. METHODS: We used IC50 values and fluorescence-activated cell sorting analysis to compare cell death in 2 ovarian cancer cell lines, namely, SKOV-3 and OVCAR-3, upon treatment with cisplatin. Moreover, the change in transcriptional levels of apoptosis-associated genes was measured with a dendron-modified DNA microarray. RESULTS: The protein levels for the up-regulated genes in each cell line were validated to identify the molecules that may determine the cellular behavior of cisplatin resistance. Eight genes were over-expressed in the 2 cell lines. The cisplatin-induced up-regulation of DAD1 in transcriptional and protein levels contributed to the cisplatin resistance of OVCAR-3, and the up-regulation of FASTK and TNFRSF11A in SKOV-3 resulted in its higher sensitivity to cisplatin than that of OVCAR-3. CONCLUSION: In the present study, we have identified a set of genes responsible for apoptosis following cisplatin treatment in ovarian cancer cell lines. These genes may give information about the understanding of cisplatin-induced apoptosis in ovarian cancer.

Induction of apoptosis by the kinase inhibitor flavopiridol in human ovarian cancer cell lines / 부인종양

OBJECTIVE: Flavopiridol that inhibits cyclin-dependent kinase, can cause cell cycle arrest, induce apoptosis in human tumor cell lines. In the present study, we investigated apoptotic effects of flavopiridol and the underlying molecular mechanisms in human ovarian cancer cell lines. METHODS: We used TOV-21G and TOV-112D cell lines. The cell viability was tested by MTT assay and apoptosis was assessed by TUNEL assay and annexin-V binding. Western blot was used to examine apoptosis related protein levels. MAP kinase activity was analyzed by non-radioactive MAP kinase assay kit. RESULTS: Treatment of TOV-21G and TOV-112D cells with flavopiridol (50 nM to 1000 nM) led to a dose- and time-dependent inhibition of cell growth and survival. Dose-related induction of apoptosis was also observed in these cell lines. Flavopiridol (500 nM) induced striking decreases in the levels of the antiapoptic proteins Mcl-1, Bcl-X(L), and XIAP in both cell lines. In contrast, expression of Bax, Bcl-2, and AIF was not significantly influenced by flavopiridol. Although flavopiridol resulted in accumulation of p53 in both cells, flavopiridol mediated apoptosis was p53 independent because it occurred to the same degree in TOV-112D cells in which p53 was inactivated by mutation. Flavopiridol treatment resulted in enhanced cleavage of pro-caspase 9 and activation of caspase 3. Apoptosis was associated with suppression of ERK activity. CONCLUSION: Although the precise mechanisms of flavopiridol mediated cytotoxicity have not been fully defined, these data suggest that flavopiridol has activity against ovarian cancers in vitro and is worthy of continued clinical development in the treatment of ovarian cancer.

Antiproliferative Effects of Mullerian Inhibiting Substance on Human Ovarian Cancer Cell Lines / 대한산부인과학회지

OBJECTIVE: In order to explore Mullerian inhibiting substance (MIS) effects on the ovarian neoplasia, the expression and localization of the MIS type II receptor (MISR II), the growth inhibitory effects of MIS, and the underlying molecular mechanisms were investigated in the ovarian cancer cell lines. METHODS: Expression of MISR II were studied in SKOV-3, OVCAR-3, and OVCAR-8 cell lines by immunohistochemical staining. The antiproliferative effects of MIS in these cell lines were investigated by methylthiazoletetrazolium (MTT) assay, fluorescence-activated cell sorting (FACS) analysis, annexin-V-FITC binding, and western blot analysis. RESULTS: All cell lines showed strong specific staining for MISR II, although staining in OVCAR-8 cells was more intense than that in SKOV-3 and OVCAR-3. Treatment of OVCAR-8 cells with MIS led to a dose- and time-dependent inhibition of cell growth and survival was determined use by MTT assay. But OVCAR-3 cells exhibited growth inhibition at higher doses after 48 hours of treatment and SKOV-3 cells did not demonstrate response. Using FACS analysis, exposure of OVCAR-8 cells to MIS (71 nM) resulted in G1 arrest after 24 hours of treatment. This pattern was changed by time-dependent increase in the percentage of cells with a sub G0G1 DNA content, suggesting apoptosis, after 48 hours of treatment. These results suggested that cell death be preceded by cell cycle arrest. Time-related induction of apoptosis was also observed in this cell line as measured by annexin-V-FITC binding. In OVCAR-8 cells, the growth inhibitory effects of MIS were mediated through specific induction of CDKI p16 protein expression and via regulation of E2F1 in the absence of detectable levels of pRb. We estimated that OVCAR-3 cells were affected by MIS through p16-independent, alternative mechanistic pathways, since the growth inhibitory effects of MIS were minimal. SKOV-3 cells did not express p16 protein. CONCLUSION: We have demonstrated that ovarian cancer cells express the MISR II. Epithelial ovarian cancer cells respond to MIS by growth inhibition. Although the precise mechanisms of MIS mediated inhibition of ovarian cancer cell growth have not been fully defined, these data suggest that MIS has activity against ovarian cancers in vitro and may also be an effective targeted therapy for ovarian cancer.

Growth Regulation of Ovarian Cancer Cells through the Inactivation of AP-1 by Retinoid Derivatives / 대한암학회지

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.