M-COPA, a Golgi Disruptor, Inhibits Cell Surface Expression of MET Protein and Exhibits Antitumor Activity against MET-Addicted Gastric Cancers

The Golgi apparatus is responsible for transporting, processing, and sorting numerous proteins in the cell, including cell surface-expressed receptor tyrosine kinases (RTK). The small-molecule compound M-COPA [2-methylcoprophilinamide (AMF-26)] disrupts the Golgi apparatus by inhibiting the activation of Arf1, resulting in suppression of tumor growth. Here, we report an evaluation of M-COPA activity against RTK-addicted cancers, focusing specifically on human gastric cancer (GC) cells with or without MET amplification. As expected, the MET-addicted cell lineMKN45 exhibited a better response to M-COPA than cell lines without MET amplification. Upon M-COPA treatment, cell surface expression of MET was downregulated with a concurrent accumulation of its precursor form. M-COPA also reduced levels of the phosphorylated form of MET along with the downstream signaling molecules Akt and S6. Similar results were obtained in additional GC cell lines with amplification of MET or the FGF receptor FGFR2. MKN45 murine xenograft experiments demonstrated the antitumor activity of M-COPAin vivo. Taken together, our results offer an initial preclinical proof of concept for the use of M-COPA as a candidate treatment option for MET-addicted GC, with broader implications for targeting the Golgi apparatus as a novel cancer therapeutic approach. (C) 2016 AACR.