Anaysis of anti-cancer effect of suberoylanilide hydroxamic acid (SAHA) in cisplatin resistant human bladder cancer cell-lines

Abstract

Introduction and Objective: Cisplatin-based chemotherapy remains first-line treatment for advanced bladder cancer. No standard chemotherapeutic agent has been established for patients with cisplatin resistant bladder cancer. We investigated the synergistic antitumor effect of suberoylanilide hydroxamic acid (SAHA) and cisplatin in cisplatin resistant bladder cancer cells. Methods: The cisplatin resistant human bladder cancer cell line (T24R2) was treated with cisplatin and/or SAHA. Tumor cell proliferation was assessed by cell counting kit-8 assay and clonogenic assay. Synergism was determined by combination index. Changes in cell cycle were determined by flow cytometry. Expression of caspase-3, 8 and 9, PARP, cytochrome c, p21, Bcl-2, Bad, p27, cyclin A, cyclin D1, and cyclin E were analyzed by Western blotting. Results: Synergistic antitumor effect between cisplatin and SAHA was observed by cell counting kit-8 assay, clonogenic assay and confirmed with combination index less than 1.0. The underlying mechanism could be synergistic cell cycle arrest, activation of apoptotic pathway including capase-3, -8, -9 and fragmented PARP or decreased expression in anti-apoptotic Bcl-2 and increased expression in pro-apoptotic BAD. Conclusions: SAHA may synergistically enhance the antitumor effect of cisplatin and re-sensitize cisplatin resistant bladder cancer cells. These findings suggest the potential use of SAHA as a combination agent to enhance the antitumor effect of cisplatin in patients with advanced bladder cancer.