Abstract 5410: Simultaneously tackling NFκB and JNK pathways to sensitise breast cancer cell lines to conventional anticancer drugs

Abstract

Many anticancer drugs induce reactive oxygen species (ROS) in cancer cells. High ROS will activate JNK pathway and induce cancer cell apoptosis. Meanwhile, ROS also strongly induces NFκB activity which triggers expression of many antiapoptotic factors and inhibits ROS/JNK pathway therefore antagonises anticancer drug-induced programmed cell death. The fate of anticancer agent-treated cancer cells is highly determined by the cross-talk between NFκB and JNK pathways. In this study, we demonstrated that a clinically used anti-alcoholism drug, disulfiram (DS), simultaneously activated ROS-JNK pathway and inhibited NFκB. DS was cytotoxic to breast cancer cell lines in vitro. As a divalent metal ion chelator, the cytotoxic effect of DS on breast cancer cell lines was highly copper-dependent. In the medium containing physiological concentration of copper (Cu, 1µM) the IC50 concentrations of DS to breast cancer cell lines were 200 - 500nM. The chemosensitizing effect of DS on 3 anti-breast-cancer agents, gemecitabine (dFdC), doxorubicine (DOX) and paclitaxel (PAC), was determined in 3 breast cancer cell lines (MCF-7, MDA-MB-231 and T47D). In combination with DS/Cu, the cytotoxicity of dFdC, DOX and PAC was significantly enhanced (Table 1. DOX: 8 - 11-fold; dFdC: 1.2 - 4-fold; PAC: 4 - 10-fold). DS also reversed dFdC resistance in acquired dFdC resistant cell lines. CI-isobologram analysis demonstrated synergistic effect between DS and anticancer drugs. Flow cytometric analysis showed DS enhanced anticancer drug-induced apoptosis. DS enhanced anticancer drug-induced ROS activity. The phosphorylated c-Jun and JNK protein in breast cancer cell lines was significantly induced by exposure of cancer cells to DS/Cu complex. Transfection of NFκB p50 and p65 induced dFdC resistance in MCF7 cells. DS inhibited drug-induced IκBα degradation and NFκB activation. Our data suggested that DS may be developed as a chemosensitizer for BC chemotherapy. *Equal contributionTable 1.DS/Cu sensitised cytotoxicity of anticancer drugs to breast cancer cell linesTreatmentsDrug: DS/CuMCF7MDA-MB-231T47DDOX (nM) 440.5 (16.2)178.5 (11.9)160.0 (5.5)DOX + DS/Cu1:540.3 (9.3)22.0 (2.0)21.5 (3.1)dFdC (nM) 22.1 (3.4)12.3 (2.2)35.0 (4.3)dFdC + DS/Cu1:104.9 (0.5)11.3 (1.2)12.4 (0.7)PAC (nM) 4.3 (1.4)9.3 (0.7)2.6 (0.3)PAC + DS/Cu1:62.50.4 (0.1)0.6 (0.02)0.7 (0.1) Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5410.