The Role of Oxidative Stress in the Development of Cisplatin Resistance in Epithelial Ovarian Cancer

Objective: To investigate the role of oxidative stress in the development of cisplatin resistance in epithelial ovarian cancer (EOC). Methods: Two parent EOC cell lines (MDAH-2774 and SKOV-3) and their chemoresistant counterparts (cisplatin, 50 mu mol/L) were used. Total RNA was extracted and subjected to real-time reverse transcriptase polymerase chain reaction to evaluate the expression of glutathione reductase (GSR) and inducible nitric oxide synthase (iNOS), as well as nitrate/nitrite levels. Analysis of variance was used for main effects and Tukey for post hoc analysis at P < .05 for statistical significance. Results: Both cisplatin resistant cell lines displayed a significant decrease in GSR messenger RNA (mRNA) levels and activity (P < .01). As compared to sensitive controls, nitrate/nitrite levels were significantly higher in SKOV-3 cisplatin resistant cells while iNOS mRNA levels were significantly higher in MDAH-2774 cisplatin resistant cells (P < .05). Conclusion: Our data suggest that the development of cisplatin resistance tilts the balance toward a pro-oxidant state in EOC.