Phosphoproteomics identifies driver tyrosine kinases in sarcoma cell lines and tumors
Menée à l'aide d'anticorps anti-phosho-tyrosine sur des lignées cellulaires et des échantillons tumoraux de sarcome, cette étude met en évidence divers récepteurs dont l'activité tyrosine kinase est essentielle à la survie des cellules cancéreuses
Driver tyrosine kinase mutations are rare in sarcomas and patterns of tyrosine phosphorylation are poorly understood. To better understand the signaling pathways active in sarcoma, we examined global tyrosine phosphorylation in sarcoma cell lines and human tumor samples. Anti-phospho-tyrosine antibodies were used to purify tyrosine-phosphorylated peptides, which were then identified using liquid chromatography and tandem mass spectrometry. The findings were validated using RNA interference, rescue, and small molecule tyrosine kinase inhibitors. We identified 1,936 unique tyrosine phosphorylated peptides, corresponding to 844 unique phospho-tyrosine proteins. In sarcoma cells alone, peptides corresponding to 39 tyrosine kinases were found. Four of ten cell lines demonstrated dependence on tyrosine kinases for growth and/or survival, including PDGFR , MET, insulin receptor/IGF1R signaling, and SRC family kinase signaling. Rhabdomyosarcoma samples demonstrated over-expression of PDGFR in 13% of examined cases, and sarcomas demonstrated abundant tyrosine phosphorylation and expression of a number of tyrosine-phosphorylated tyrosine kinases, including DDR2, EPHB4, TYR2, AXL, SRC, LYN, and FAK. Together, our findings suggest that integrating global phosphoproteomics with functional analyses using kinase inhibitors can identify drivers of sarcoma growth and survival.