HGF regulates VEGF expression via the c-Met receptor downstream pathways, PI3K/Akt, MAPK and STAT3, in CT26 murine cells

作者：Matsumura Atsushi; Kubota Takeshi^*; Taiyoh Hiroaki; Fujiwara Hitoshi; Okamoto Kazuma; Ichikawa Daisuke; Shiozaki Atsushi; Komatsu Shuhei; Nakanishi Masayoshi; Kuriu Yoshiaki; Murayama Yasutoshi; Ikoma Hisashi; Ochiai Toshiya; Kokuba Yukihito; Nakamura Takahiro; Matsumoto Kunio; Otsuji Eigo

来源：International Journal of Oncology, 2013, 42(2): 535-542.

DOI：10.3892/ijo.2012.1728

• hepatocyte growth factor
• c-Met
• NK4
• vascular endothelial cell growth factor
• angiogenesis
• CT26

In the present study, we assessed the involvement of hepatocyte growth factor (HGF)/c-Met signalling with vascular endothelial cell growth factor (VEGF) and hypoxia inducible factor (HIF)-1 alpha expression in the downstream pathways phosphatidylinositol 3-kinase (PI3K)/Akt, mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) in CT26 cells, to determine the mechanisms of the potent anti-angiogenic effect of NK4. We established genetically modified CT26 cells to produce NK4 (CT26-NK4). VEGF expression in subcutaneous CT26 tumours in vivo and in culture supernatants in vitro was determined by ELISA. HIF-1 alpha expression in nuclear extracts was evaluated by western blot analysis. VEGF and HIF-1 alpha mRNA levels were examined by real-time reverse transcription-polymerase chain reaction (RT-PCR). The DNA binding activity of HIF-1 alpha was evaluated using an HIF-1 alpha transcription factor assay kit. Our results demonstrated that VEGF expression was reduced in homografts of CT26-NK4 cells, compared to those of the control cells. In vitro, VEGF expression, which was induced by HGF, was inhibited by anti-HGF antibody, NK4 and by kinase inhibitors (PI3K, LY294002; MAPK, PD98059; and STAT3, Stattic). HGF-induced HIF-1 alpha transcriptional activity was also inhibited by the kinase inhibitors. Real-time RT-PCR demonstrated that HGF-induced HIF-1 alpha mRNA expression was not inhibited by LY294002 and PD98059, but was inhibited by Stattic. These data suggest that the PI3K/Akt, MAPK and STAT3 pathways, downstream of HGF/c-Met signalling, are involved in the regulation of VEGF expression in CT26 cells. HGF/c-Met signalling may be a promising target for anti-angiogenic strategies.

• 出版日期2013-2