Arsenic sulfide amplifies JQ1 toxicity via mitochondrial pathway in gastric and colon cancer cells
Authors Tan Z, Zhang X, Kang T, Zhang L, Chen S
Received 20 July 2018
Accepted for publication 24 September 2018
Published 14 November 2018 Volume 2018:12 Pages 3913—3927
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 3
Editor who approved publication: Dr Tuo Deng
Zhen Tan,* Xiuli Zhang,* Ting Kang, Lian Zhang, Siyu Chen
Department of Oncology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
*These authors contributed equally to this work
Purpose: Gastric and colon cancers have been the leading causes of cancer mortality in the world with limited therapy. Small molecules binding to bromodomains of bromodomain-containing protein 4 (BRD4) exert strong antitumor activities against hematological malignancies, while generally have limited efficacy in advanced solid tumors. Here, we found that the bromodomain and extra-terminal (BET)-bromodomain inhibitor JQ1, when combined with arsenic sulfide (As4S4, abbreviated as AS), synergistically decreased the expression of nuclear factor of activated T-cells (NFATs) as well as the downstream oncogene c-Myc and largely induced cell apoptosis via mitochondrial pathway in gastric and colon cancer cell lines.
Methods: The synergistic cytotoxicity of AS and JQ1 in gastric and colon cancer cells was determined by MTT assay and verified by FACS assay. Western blot analysis and quantitative real-time PCR (qPCR) assay were used to detect the expression of NFATs and downstream apoptotic proteins. The mitochondrial transmembrane potential was determined by FACS assay, and the metastasis of cancer cells was detected by the wound-healing assay.
Results: AS and JQ1 synergistically induced cell apoptosis in gastric and colon cancer cells by downregulating NFATs and upregulating apoptotic proteins. Combination of AS and JQ1 was associated with the decreased mitochondrial transmembrane potential, the cytochrome c release, and the subsequent caspase-3 activation.
Conclusion: Thus, our data indicate that AS can effectively enhance the cytotoxicity of BET inhibitors in gastric and colon cancer cells through mitochondrial-mediated apoptosis induction.
Keywords: arsenic sulfide, JQ1, NFAT, apoptosis, mitochondria
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