Abstract 2058: Co-treatment of NVP-BSK805 highly sensitizes drug-resistant cancer cells by increasing P-gp inhibition

Abstract

Abstract The high expression of P-glycoprotein (P-gp) is consistently observed in multidrug resistance (MDR) cancer cells. The purpose of our study is to identify conditions that could increase the sensitivity of P-gp-overexpressing the drug-resistant KBV20C cancer cell line. We have used the commercially-available epigenetic library, which includes 128 compounds. Using the cellular viability test, we also identified that NVP-BSK805 is highly sensitized to KBV20C-resistant cells and vincristine treatment. However, NVP-BSK805-induced sensitization was not observed in vincristine-treated sensitive KB parent cells, suggesting that the effects are specific to resistant cancer cells. Using FACS analysis, western blot, and Annexin V staining, we identified that NVP-BSK805 sensitized vincristine-treated KBV20C cells arrest via apoptosis and G2. Furthermore, sensitization potency of NVP-BSK805, in combination with vincristine, was measured in KBV20C cells when comparing them with P-gp inhibitor verapamil or another Jak2 inhibitor CEP-33779. We further investigated the mechanisms of NVP-BSK805 against sensitization of vincristine-treated KBV20C cells. The sensitization mechanism of NVP-BSK805 was mainly dependent on the inhibition of P-gp. In addition, ATPase activity was conducted to identify its potential role in NVP-BSK805 for P-gp inhibition. Both NVP-BSK805 and CEP-33779 showed high binding affinity docking scores -9.1 and -7.4, respectively, against the ABCB1 receptor protein. Collectively, inhibition of P-gp by NVP-BSK805 can increase vincristine-sensitivity in MDR cancer cells through increased apoptosis and G2 arrest. Our findings indicate that the Jak2 inhibitor may be a promising target in the treatment of patients resistant to antimitotic drugs. Citation Format: Yu Jin Park, Ji Hyun Cheon, Ji Yeon Son, Sung Pil Yoon, Hyung Sik Kim. Co-treatment of NVP-BSK805 highly sensitizes drug-resistant cancer cells by increasing P-gp inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2058. doi:10.1158/1538-7445.AM2017-2058