Targeting antioxidant enzymes enhances the therapeutic efficacy of the BCL-X
Cancer Lett 2020 Oct 15; 497:123-136
Cancer chemotherapeutic drugs exert cytotoxic effects by modulating intracellular reactive oxygen species (ROS) levels. However, whether ROS modulates the efficacy of targeted therapeutics remains poorly understood. Previously, we reported that upregulation of the anti-apoptotic protein, BCL-XL, by KRAS activating mutations was a potential target for KRAS-mutant colorectal cancer (CRC) treatment. Here, we demonstrated that the BCL-XL targeting agent, ABT-263, increased intracellular ROS levels and targeting antioxidant pathways augmented the therapeutic efficacy of this BH3 mimetic. ABT-263 induced expression of genes associated with ROS response and increased intracellular ROS levels by enhancing mitochondrial superoxide generation. The superoxide dismutase inhibitor, 2-methoxyestradiol (2-ME), exhibited synergism with ABT-263 in KRAS-mutant CRC cell lines. This synergistic effect was attributed to the inhibition of mTOR-dependent translation of the anti-apoptotic MCL-1 protein via caspase 3-mediated cleavage of AKT and S6K. In addition, combination treatment of ABT-263 and 2-ME demonstrated a synergistic effect in in vivo patient-derived xenografts harboring KRAS mutations. Our data suggest a novel role for ROS in BH3 mimetic-based targeted therapy and provide a novel strategy for treatment of CRC patients with KRAS mutations.
Oh, Yumi; Jung, Hae Rim; Min, Seoyeon; Kang, Jinjoo; Jang, Dongjun; Shin, Seungjae; Kim, Jiwon; Lee, Sang Eun; Sung, Chang Ohk; Lee, Won-Suk; Lee, Charles; Lee, Charles; and Cho, Sung-Yup, "Targeting antioxidant enzymes enhances the therapeutic efficacy of the BCL-X" (2020). Faculty Research 2020. 233.