Abstract 290: A novel function of HGF in the activation of Chk1 phosphorylation in colon cancer cells

Abstract

Abstract ATR/Chk1 pathway plays an essential role in modulation of DNA damage response (DDR) and homologous recombination (HR). Particularly, Chk1 phosphorylation is involved in cancer prognosis and therapeutic resistance. Although some receptor tyrosine kinases (RTKs) participate in the regulation of Chk1 phosphorylation, the effect of hepatocyte growth factor (HGF) on Chk1 phosphorylation is unknown. In the present study, Western blotting and subcellular fractionation were performed to identify the expression and the location of Chk1 phosphorylation in the presence of HGF. With small interfering RNA transfections, co-immunoprecipitations were performed to detect the interaction between TopBP1 and ATR complex. Our results demonstrated that HGF moderately activated Chk1 phosphorylation in colon cancer cells via upregulation of TopBP1, RAD51, and complex formation of TopBP1 and ATR. Furthermore, AKT activation promoted by HGF served as an important intermediator linking HGF/MET signaling and Chk1 phosphorylation. Depletion of AKT activity attenuated expression of basal line p-Chk1 and induced Chk1 activation due to HGF stimulation. Meantime, activation of AKT directly regulated expression of TopBP1 and RAD51. Suppression of AKT restored HGF-induced upregulation of TopBP1, RAD51, and enhancement of TopBP1/ATR complex as well. Our studies showed that HGF was implicated in regulating Chk1 phosphorylation and further demonstrated that AKT activity was responsible for HGF-induced Chk1 phosphorylation, which might potentially result in management of prognosis and therapeutic sensitivity in cancer therapy. Note: This abstract was not presented at the meeting. Citation Format: Na Song, Xiaofang Che, Xiujuan Qu, Lu Xu, Kezuo Hou, Yunpeng Liu. A novel function of HGF in the activation of Chk1 phosphorylation in colon cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 290. doi:10.1158/1538-7445.AM2017-290