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Differential Responses of MET Activations to MET kinase Inhibitor and Neutralizing Antibody

Background: Aberrant MET tyrosine kinase signaling is known to cause cancer initiation and progression. While MET inhibitors are in clinical trials against several cancer types, the clinical efficacies are controversial and the molecular mechanisms toward sensitivity remain elusive. Methods: With the goal to investigate the molecular basis of MET amplification (MET amp ) and hepatocyte growth factor (HGF) autocrine-driven tumors in response to MET tyrosine kinase inhibitors (TKI) and neutralizing antibodies, we compared cancer cells harboring MET amp (MKN45 and MHCCH97H) or HGF-autocrine (JHH5 and U87) for their sensitivity and downstream biological responses to a MET-TKI (INC280) and an anti-MET monoclonal antibody (MetMab) in vitro, and for tumor inhibition in vivo. Results: We find that cancer cells driven by MET amp are more sensitive to INC280 than are those driven by HGF-autocrine activation. In MET amp cells, INC280 induced a DNA damage response with activation of repair through the p53BP1/ATM signaling pathway. Although MetMab failed to inhibit MET amp cell proliferation and tumor growth, both INC280 and MetMab reduced HGF-autocrine tumor growth. In addition, we also show that HGF stimulation promoted human HUVEC cell tube formation via the Src pathway, which was inhibited by either INC280 or MetMab. These observations suggest that in HGF-autocrine tumors, the endothelial cells are the secondary targets MET inhibitors. Conclusions: Our results demonstrate that MET amp and HGF-autocrine activation favor different molecular mechanisms. While combining MET TKIs and ATM inhibitors may enhance the efficacy for treating tumors harboring MET amp , a combined inhibition of MET and angiogenesis pathways may improve the therapeutic efficacy against HGF-autocrine tumors.

Identiferoai:union.ndltd.org:ETSU/oai:dc.etsu.edu:etsu-works-11484
Date12 September 2018
CreatorsKou, Jianqun, Musich, Phillip R., Staal, Ben, Kang, Liang, Qin, Yuan, Yao, Zhi Q., Zhang, Boheng, Wu, Weizhong, Tam, Angela, Huang, Alan, Hao, Huai Xiang, Vande Woude, George F., Xie, Qian
PublisherDigital Commons @ East Tennessee State University
Source SetsEast Tennessee State University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceETSU Faculty Works
Rightshttp://creativecommons.org/licenses/by/4.0/

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