Disulfiram potentiates docetaxel cytotoxicity in breast cancer cells through enhanced ROS and autophagy.

Abstract

Recent studies have demonstrated that autophagy plays a critical role in reducing the drug sensitivity of docetaxel (DTX) therapy. Disulfiram (DSF) has exhibited potent autophagy inducing activity in multiple studies. We hypothesized that DSF co-treatment could sensitize breast cancer cells to DTX therapy via autophagy modulation. Breast cancer cells, MCF7, and 4T1, were treated with DTX and DSF, alone and in combination. The effects were analyzed by evaluating cytotoxicity, induction of apoptosis, induction of autophagy, and reactive oxygen species (ROS) generation. In addition, the consequence of autophagy and ROS inhibition on the DTX + DSF mediated cytotoxicity was also evaluated. Significant synergism in cytotoxicity was observed with DTX + DSF combination in breast cancer cells, MCF7, and 4T1. Hyper induction of ROS and autophagy was also found with the combination treatment. ROS inhibition by N-Acetyl Cysteine (NAC), as well as autophagy inhibition by ATG5 silencing significantly reduced the autophagy level as well as cytotoxicity of the DTX + DSF combination, indicating that the induction of autophagy mediated by high ROS generation played a critical role behind the synergistic cytotoxicity. This study indicates that DTX + DSF combination therapy can effectively sensitize cancer cells by hyper inducing autophagy through ROS generation and can be developed as a therapeutic strategy for cancer treatment in the future.