Expression of UCP2 is associated with sensitivity to platinum-based chemotherapy for ovarian serous carcinoma

The standard treatment for ovarian serous carcinoma is maximum debulking surgery and platinum-based chemotherapy. Despite the high response rate for chemotherapy, the majority of patients will be resistant to first-line agents and the prognosis for these patients is particularly poor. Currently there are no reliable methods to determine or predict platinum resistance. Uncoupling protein 2 (UCP2) is widely expressed in cancer cells and regulates the production of mitochondrial reactive oxygen species (ROS). A reduction in ROS is associated with carcinogenesis and chemoresistance. Downregulation of UCP2 significantly causes increased cell death following chemotherapy. The present study investigated the association between UCP2 expression and platinum sensitivity. The study included 54 patients with ovarian serous carcinoma (FIGO stages III and IV) who were treated at Osaka City University Hospital between January 2005 and December 2012. Patients were divided into a platinum-sensitive group (n=27) and platinum-resistant group (n=27) based on the platinum-free interval, which was calculated from the time of last platinum administration to the time of recurrence. UCP2 expression in human ovarian serous carcinoma cells was inhibited by genipin, and changes in carboplatin sensitivity were examined. The UCP2 weighted score was lower in the platinum-sensitive group than in the platinum resistant-group (P=0.005). In addition, patients in the low UCP2 expression group were more sensitive to platinum-based chemotherapy than those in the high UCP2 expression group (P=0.001). Sensitivity to carboplatin was significantly increased when UCP2 was inhibited in human ovarian serous carcinoma cells in vitro. UCP2 expression may be a predictive marker of the efficacy of platinum-based chemotherapy for patients with ovarian serous carcinoma.