EGFR‐mediated signaling pathway influences the sensitivity of oral squamous cell carcinoma to JQ1

作者：Xiaojing Liu, Qing Li, Ping Huang, Dongdong Tong, Haitao Wu, Fenghe Zhang · 发表于：Journal of Cellular Biochemistry · 年份：2018 · DOI：10.1002/jcb.26920 · 被引用次数：30 · 研究领域：Protein Degradation and Inhibitors、Chromatin Remodeling and Cancer、Multiple Myeloma Research and Treatments

Inhibiting BRD4 has emerged as a promising anticancer strategy, and inhibitors such as JQ1 can suppress cell growth in oral squamous cell carcinoma (OSCC). However, the mechanism through which JQ1 exerts its anticancer activity has not been reported. Moreover, JQ1 does not markedly inhibit proliferation and increase apoptosis in OSCC when used as a monotherapy. Herein, we explore the mechanism of JQ1 in OSCC and probe ways to increase its therapeutic potential. In this study, we used two cell lines, Cal27, and Scc25. We found that BRD4 was highly expressed in OSCC tissues when compared with adjacent non-tumor tissues, and JQ1 worked through the EGFR-mediated signaling pathway in tumor cells. Furthermore, we demonstrated that JQ1 induced an increased treatment effect in vitro and in vivo when combined with a PI3K inhibitor. Interestingly, subsequent mechanistic analyses indicated that further suppressing EGFR and BRD4 expression was instrumental to this functional synergism. Moreover, we found that upregulating EGFR expression by EGF stimulation protected cells treated with JQ1 from apoptosis, while knockdown of EGFR before addition of JQ1 successfully mimicked the combination treatment results. In summary, our findings revealed that JQ1 can act by inhibiting the EGFR-mediated signaling pathway, and EGFR expression influences the sensitivity of OSCC to JQ1. Regarding clinical use, this study demonstrates that BRD4 is a novel therapeutic target and EGFR can be used as a biomark...