Next-generation proteasome inhibitor MLN9708 sensitizes breast cancer cells to doxorubicin-induced apoptosis

• DOI: 10.1038/srep26456
• Publication Date: 2016-05-24T17:18:42Z
• Authors: Hao Wang; Yang Yu; Zheng Jiang; Wen-Ming Cao; Zhenyu Wang; Jun Dou; Yanling Zhao; Yunfu Cui; Hong Zhang
• Keywords: Boron Compounds; 0301 basic medicine; Cell Survival; MAP Kinase Signaling System; Glycine; Breast Neoplasms; Drug Synergism; Dual Specificity Phosphatase 1; Article; 3. Good health; Gene Expression Regulation, Neoplastic; 03 medical and health sciences; Doxorubicin; Cell Line, Tumor; Autophagy; MCF-7 Cells; Humans; Female; Drug Screening Assays, Antitumor; Phosphorylation; Proteasome Inhibitors; Cell Proliferation

AbstractDoxorubicin (Dox), one of the most effective chemotherapy drug for cancer treatment, is limited by its severe side effects and chemoresistance. Dox induces DNA damage and leads to significant proteomic changes in the cancer cells, which makes the ubiquitin-proteasome system a potential target to enhance the efficacy of Dox therapy. The unsuccessful clinical trials of proteasome inhibitor PS-341 (bortezomib) in solid tumors led to the invention of MLN9708 (ixazomib), an orally bioavailable next-generation proteasome inhibitor with improved pharmacokinetic and pharmacodynamic features. In this preclinical study, we used eight human breast cancer cell lines, which represent the major molecular subtypes of breast cancer, to validate the cytotoxic effects of MLN9708, alone and in combination with Dox. We found that MLN9708 had cytotoxic effects, induced autophagy and MKP-1 expression, and enhanced Dox-induced apoptosis in these cell lines. MLN9708 also enhanced Dox-induced JNK and p38 phosphorylation and inhibited Dox-induced IκBα degradation. Our in vitro results suggest that MLN9708 has antitumor effects in breast cancer and can sensitize breast cancer cells to Dox treatment. This promising combination may be an effective and feasible therapeutic option for treating breast cancer and warrants clinical validation.