Hydroxychloroquine synergizes with the PI3K inhibitor BKM120 to exhibit antitumor efficacy independent of autophagy

Journal of Experimental & Clinical Cancer Research

Feng Wang¹  Zhe-Sheng Chen²  Yuqi Yang²  Francois X. Claret³  Yuxu Zhong⁴  Moshe Elkabets⁵  Zhenxing Zhong⁶  Wenhui Jiao⁶  Ran Wang⁶  Xin Peng⁷  Dexin Kong⁸  Shaolu Zhang⁹ 

[1] Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China;Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John’s University, 11439, Queens, NY, USA;Department of Systems Biology, The University of Texas MD Anderson Cancer Center, 77030, Houston, TX, USA;State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 100850, Beijing, China;The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, 84105, Beer-Sheva, Israel;Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, 300070, Tianjin, China;Key Laboratory of Immune Microenvironment and Diseases (Ministry of Education), Tianjin Medical University, 300070, Tianjin, China;Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, 300070, Tianjin, China;Key Laboratory of Immune Microenvironment and Diseases (Ministry of Education), Tianjin Medical University, 300070, Tianjin, China;Department of Systems Biology, The University of Texas MD Anderson Cancer Center, 77030, Houston, TX, USA;Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, 300070, Tianjin, China;Key Laboratory of Immune Microenvironment and Diseases (Ministry of Education), Tianjin Medical University, 300070, Tianjin, China;School of Medicine, Tianjin Tianshi College, Tianyuan University, 301700, Tianjin, China;Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, 300070, Tianjin, China;Key Laboratory of Immune Microenvironment and Diseases (Ministry of Education), Tianjin Medical University, 300070, Tianjin, China;State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 100850, Beijing, China;

关键词: Hydroxychloroquine;    BKM120;    Autophagy;    Homologous recombination repair;    ROS;    PI3K;    NRF2;   

DOI  :  10.1186/s13046-021-02176-2

来源: Springer

【 摘 要 】

BackgroundThe critical role of phosphoinositide 3-kinase (PI3K) activation in tumor cell biology has prompted massive efforts to develop PI3K inhibitors (PI3Kis) for cancer therapy. However, recent results from clinical trials have shown only a modest therapeutic efficacy of single-agent PI3Kis in solid tumors. Targeting autophagy has controversial context-dependent effects in cancer treatment. As a FDA-approved lysosomotropic agent, hydroxychloroquine (HCQ) has been well tested as an autophagy inhibitor in preclinical models. Here, we elucidated the novel mechanism of HCQ alone or in combination with PI3Ki BKM120 in the treatment of cancer.MethodsThe antitumor effects of HCQ and BKM120 on three different types of tumor cells were assessed by in vitro PrestoBlue assay, colony formation assay and in vivo zebrafish and nude mouse xenograft models. The involved molecular mechanisms were investigated by MDC staining, LC3 puncta formation assay, immunofluorescent assay, flow cytometric analysis of apoptosis and ROS, qRT-PCR, Western blot, comet assay, homologous recombination (HR) assay and immunohistochemical staining.ResultsHCQ significantly sensitized cancer cells to BKM120 in vitro and in vivo. Interestingly, the sensitization mediated by HCQ could not be phenocopied by treatment with other autophagy inhibitors (Spautin-1, 3-MA and bafilomycin A1) or knockdown of the essential autophagy genes Atg5/Atg7, suggesting that the sensitizing effect might be mediated independent of autophagy status. Mechanistically, HCQ induced ROS production and activated the transcription factor NRF2. In contrast, BKM120 prevented the elimination of ROS by inactivation of NRF2, leading to accumulation of DNA damage. In addition, HCQ activated ATM to enhance HR repair, a high-fidelity repair for DNA double-strand breaks (DSBs) in cells, while BKM120 inhibited HR repair by blocking the phosphorylation of ATM and the expression of BRCA1/2 and Rad51.ConclusionsOur study revealed that HCQ and BKM120 synergistically increased DSBs in tumor cells and therefore augmented apoptosis, resulting in enhanced antitumor efficacy. Our findings provide a new insight into how HCQ exhibits antitumor efficacy and synergizes with PI3Ki BKM120, and warn that one should consider the “off target” effects of HCQ when used as autophagy inhibitor in the clinical treatment of cancer.

【 授权许可】

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