Cancer-associated fibroblasts attenuate Cisplatin-induced apoptosis in ovarian cancer cells by promoting STAT3 signaling

One of the main reasons for treatment failure in ovarian cancer is acquired drug resistance. Cancer associated fibroblasts (CAFs) are known to enhance chemoresistance in many human tumors. However, its contributions to chemoresistance acquisition in ovarian cancer are not well understood. Here, we provide the first evidence that the conditioned medium of CAFs (CAFs-CM) could attenuate the sensitivity to Cisplatin in A2780 and ES2 ovarian cancer cells and protect them from Cisplatin-induced apoptosis. We found the expression level of two anti-apoptotic proteins, Bcl-2 and Survivin, as well as their upstream controller p-STAT3 were significantly increased when ovarian cancer cells were exposed to CAFs-CM. Furthermore, inhibition of STAT3 signaling with Cryptotanshinone could down-regulate the expression of Bcl-2 and Survivin, thus weaken the post-target resistance to Cispaltin mediating by CAFs-CM in ovarian cancer cells. In conclusion, our data suggested that CAFs could activate the anti-apoptotic STAT3 signaling, thereby decrease the Cisplatin-induced apoptosis and promote chemoresistance in ovarian cancer.