MiR-424-3p suppresses galectin-3 expression and sensitizes ovarian cancer cells to cisplatin.

PURPOSE: Assessment of miR-424-3p mimic capability to sensitize SK-OV-3 and TOV-21G ovarian cancer cells to cisplatin by decreasing the expression of galectin-3, which is an anti-apoptotic protein overexpressed in ovarian cancer and associated with resistance to chemotherapy. METHODS: We performed a reverse transfection of miR-424-3p mimic into SK-OV-3 and TOV-21G ovarian cancer cells, followed by Real Time™ RT-PCR analysis of the expression of miR-424-3p and galectin-3 mRNA as well as ELISA assay for galectin-3 protein level. Next, we studied the viability (XTT assay), proliferation (EdU incorporation assay), and apoptosis (ELISA assay) of the both cell lines transfected with the mimic and treated with cisplatin. RESULTS: We demonstrated that miR-424-3p mimic effectively transfects into SK-OV-3 and TOV-21G ovarian cancer cells in which it significantly suppresses the expression of galectin-3 at the protein level, but not at the mRNA level. Reverse transfection of both cell lines with the mimic, followed by treatment with cisplatin, resulted in a reduction in cell viability and proliferation as well as an increase in the induction of apoptosis. CONCLUSIONS: MiR-424-3p mimic sensitizes SK-OV-3 and TOV-21G ovarian cancer cells to cisplatin by decreasing the expression of galectin-3.

Morin decreases galectin-3 expression and sensitizes ovarian cancer cells to cisplatin.

PURPOSE: This study aimed at evaluating whether morin (a natural flavonoid and a known inhibitor of NF-κB) can sensitize ovarian cancer cells to cisplatin by decreasing the expression of galectin-3, which is an anti-apoptotic protein regulated by NF-κB transcription factor. METHODS: To assess the possibility of augmentation the activity of cisplatin by morin, we studied the separate and the combined effect of morin and cisplatin on viability, proliferation, and apoptosis of TOV-21G (cisplatin-sensitive) and SK-OV-3 (cisplatin-resistant) ovarian cancer cells. We also analysed the effect of morin and cisplatin on galectin-3 expression at the mRNA and protein levels. RESULTS: We demonstrated that morin possess antitumor activity against TOV-21G and SK-OV-3 ovarian cancer cells by reducing cell viability and proliferation as well as increasing the induction of apoptosis. Co-treatment of the cells with selected concentrations of morin and cisplatin, accordingly to specific treatment approaches, reveals a synergism, which leads to sensitization of the cells to cisplatin. During this sensitization, morin significantly reduces the expression of galectin-3 at the mRNA and protein level, regardless of the presence of cisplatin. CONCLUSIONS: Morin sensitizes TOV-21G and SK-OV-3 ovarian cancer cells to cisplatin, what is associated with a decrease of the expression of galectin-3.

DNA methyltransferase inhibitors influence on the DIRAS3 and STAT3 expression and in vitro migration of ovarian and breast cancer cells.

OBJECTIVES: Downregulation of DIRAS3 (DIRAS family, GTP-binding Ras-like 3) is related to ovarian and breast cancer progression. A possible mechanism that silences this gene is the promoter region DNA methylation. The potential reversibility of this epigenetic mechanism makes it more attractive candidate for new mode of cancer treatment. DIRAS3 regulates cell cycle, tumor dormancy and inhibits cancer cell growth and motility, all of which may indirectly depend on interaction with STAT3 (Signal Transducer and Activator of Transcription 3) classified as a potential oncogene. The restoration of DIRAS3 expression could inhibit cell proliferation and invasiveness. MATERIAL AND METHODS: Human ovarian carcinoma cell line (A2780) and human breast cancer cell line (MCF7) were exposed to two DNA methyltransferase inhibitors (DNMTi): decitabine (5-aza-2'-deoxycytidine) [25 µM and 12.5 µM] and RG108 [150 µM and 100 µM]. In vitro migration changes of cancer cells were examined with wound healing assay. After 7 days of DNMTi treatment cells were harvested and DNA and RNA was isolated. The methylation status of the promoter sequences of DIRAS3 and STAT3 genes was determined using methylation specific PCR (MS-PCR). Level of target genes' expression was quantified using quantitative reverse transcription PCR (QRT-PCR). RESULTS AND CONCLUSIONS: The in vitro wound healing assay showed changes in the migration rate of both adherent cell lines after DNMTi treatment compared to the untreated cells. Relative balance between methylated and unmethylated variants of DIRAS3 after MS-PCR was shifted towards unmethylated version after DNMTi treatment in A2780 cells. Statistically significant dose dependent effect of decitabine and RG108 on DIRAS3 expression in A2780 cells was observed.