BNIP3 contributes to cisplatin-induced apoptosis in ovarian cancer cells

BNIP3 is a proapoptotic protein that mediates apoptosis, necrosis and autophagy. However, the involvement of BNIP3 in cisplatin-induced apoptosis in ovarian cancer is not clear. In this study, we examined the role of BNIP3 in ovarian cancer during cisplatin treatment and its correlation with clinical outcomes. We first measured cisplatin cytotoxicity and BNIP3 levels before and after cisplatin exposure for ovarian cancer cell lines A2780, SKOV3, OVCAR4, OV2008, ES2 and HO8910. BNIP3 was observed to be differentially expressed in these cell lines, and cisplatin induced a significant increase in BNIP3 levels in A2780 and OVCAR4. BNIP3 knockdown with siRNA in A2780 and OVCAR4 significantly reduced cisplatin cytotoxicity in these two cell lines and alleviated cisplatin-induced apoptosis. We searched the online databases Gene Expression Omnibus and The Cancer Genome Atlas to analyze the correlation between BNIP3 level and overall survival and progression-free survival in patients with ovarian cancer. Pooled analyses showed that higher BNIP3 level was correlated with poorer overall survival (95% confidence intervals; hazard ratio = 1.18, 1.04-1.34;P = 0.013) and progression-free survival (95% confidence intervals; hazard ratio = 1.26, 1.10-1.43;P = 0.00049). However, the results of individual datasets and stratification analyses of histology, FIGO (Federation Internationale de Gynecolgie et d'Obstetrique) stage, chemotherapy regimen and P53 mutation status varied. These findings indicate that cisplatin-induced apoptosis is dependent on BNIP3 level in ovarian cancer cell lines. Targeting BNIP3 may therefore be a potential way of restoring cisplatin sensitivity.