Multi-Modal Kinome Profiling Discovers Mesenchymal-Like Polarity Networks that Underly Directed Hepatocellular Carcinoma Cell Migration

Metastasis and associated therapy resistance remain the principal drivers of cancer related death, and there is a pressing need for a deeper mechanistic understanding and anti-metastatic therapies. For patients that suffer from hepatocellular carcinomas (HCCs), which are the most common primary liver cancers, frequent systemic metastasis results in bleak 5-year survival prognoses of only 4%. To metastasize, carcinoma cells must acquire an invasive phenotype, which typically requires switching from an epithelial-like apical-basal polarity to the front-rear polarity of mesenchymal-like cells. Signaling cues that originate in the tumor microenvironment can activate cellular morphogenic programs that drive polarity switching, like the epithelial-mesenchymal transition (EMT). Protein kinases control most cell signaling pathways and are highly actionable drug targets; however, systematic studies determining the kinases that underly the epithelial-mesenchymal polarity switch (EMPS) are lacking. We developed an assay platform that integrates mass spectrometry (MS)-based kinome profiling, broadly capturing kinase network activity, with chemical genetic screening using selective kinase inhibitors and quantitative phase imaging (QPI), serving as the phenotypic readout. Applying this approach that we dubbed morphokin-MS, to epithelial-like HCC cell lines that we induced to undergo EMPS identified a conserved network of 12 kinases that contributed to HCC cell polarity switching and directed cell migration; MS-based kinome profiling of 17 HCC patient tumors showed that these kinase are frequently upregulated in human tumors. morphokin-MS also revealed that death-associated protein kinase 3 (DAPK3) is one of the principal drivers of the EMPS and directed HCC cell migration. Thus, our mechanistic studies revealed that DAPK3 forms a complex with DAPK1 and filamin-A inter-acting protein 1-like (FILIP1L), which act as scaffold proteins that recruit DAPK3 to the centrosome. Pharmaco-logical and genetic inhibition of the DAPK1-DAPK3-FILIP1L complex blocked centrosome repositioning and microtubule polarization toward the leading edge of mesenchymal-like HCC cells, directed cell migration, and invasion. Our morphokin-MS method and comprehensive kinome profiling data will serve as a valuable resource for the cancer research community; our discovery of an inducible mesenchymal-like DAPK1-DAPK3-FILIP1L polarity complex that controls centrosome positioning in motile HCC cells may lead to the development of novel therapeutics for combatting cancer metastasis.