Abstract 762: Prevention and reversion of multidrug resistance (MDR) in cancer by NSC23925

Abstract

Abstract The major limitation to the success of chemotherapy in cancer is the development of multidrug resistance (MDR). Preventing the emergence of MDR during chemotherapy treatment has been a high priority of clinical and investigational oncology, but remains an elusive goal. NSC23925 has recently been identified as a novel and potent MDR reversal agent. However, whether NSC23925 can prevent the development of MDR in cancer is unknown. Therefore, this study was to evaluate the effects of NSC23925 on prevention and reversion of MDR. Human osteosarcoma cell line U-2OS and Saos were exposed to increasing concentrations of taxol alone or in combination with NSC23925 for 6 months. The results showed that cells selected with increasing concentrations of taxol alone developed MDR with resistance to taxol and other Pgp substrates, while cells cultured with taxol-NSC23925 simultaneously prevented the development of MDR and cells remained sensitive to chemotherapeutic agents. Taxol selected resistant cells showed high expression and activity of drug transporter P-glycoprotein (Pgp), whereas taxol-NSC23925 combination treatment prevented the expression of Pgp. Our findings suggest that NSC23925 may prevent the development of MDR by specifically preventing the overexpression of Pgp. Moreover, NSC23925 can reverse MDR in drug resistant cells by modulating Pgp activity. Given the significant incidence of MDR in cancer and the lack of effective agents for prevention and revision of MDR, NSC23925 and derivatives hold the potential to improve the outcome of cancer patients with poor prognosis due to drug resistance. Citation Format: Xiaoqian Yang, Francis Hornicek, Zhenfeng Duan. Prevention and reversion of multidrug resistance (MDR) in cancer by NSC23925. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 762. doi:10.1158/1538-7445.AM2014-762