title: Cellular transformation and activation of the phosphoinositide-3-kinase-Akt cascade by the ETV6-NTRK3 chimeric tyrosine kinase requires c-Src.
abstract: The ETV6-NTRK3 (EN) chimeric tyrosine kinase, a potent oncoprotein expressed in tumors derived from multiple cell lineages, functions as a constitutively active protein-tyrosine kinase. ETV6-NTRK expression leads to the constitutive activation of two major effector pathways of wild-type NTRK3, namely, the Ras-mitogen-activated protein kinase (MAPK) mitogenic pathway and the phosphoinositide-3-kinase (PI3K)-Akt pathway mediating cell survival, and both are required for EN transformation. However, it remains unclear how ETV6-NTRK3 activates Ras-Erk1/2 and/or PI3K-Akt cascades. Here, we define some aspects of the molecular mechanisms regulating ETV6-NTRK-dependent Ras-Erk1/2 and PI3K-Akt activation. We show that ETV6-NTRK3 associates with c-Src, and that treatment with SU6656, a c-Src inhibitor, completely blocks ETV6-NTRK-transforming activity. Treatment of NIH3T3 cells expressing ETV6-NTRK3 with SU6656 attenuated the activation of Ras-Erk1/2 and PI3K-Akt. Suppression of c-Src by RNA interference in NIH3T3-ETV6-NTRK3 cells resulted in markedly decreased expression of cyclin D1 and suppression of activation of Ras-Erk1/2 and PI3K-Akt. However, in Src-deficient cells, the ETV6-NTRK3 failed to activate the PI3K-Atk pathway, but not the Ras-Erk1/2 pathway. Therefore, these data indicate that ETV6-NTRK3 induces the PI3K-Akt cascade through the activation of c-Src.
authors.affiliation: Laboratory of Cancer Biology and Genetics, National Cancer Institute, Bethesda, Maryland, USA.
authors.forename: Wook
authors.initials: W
authors.lastname: Jin
authors.forename: Chohee
authors.initials: C
authors.lastname: Yun
authors.forename: Amy
authors.initials: A
authors.lastname: Hobbie
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Martin
authors.forename: Poul H B
authors.initials: PH
authors.lastname: Sorensen
authors.forename: Seong-Jin
authors.initials: SJ
authors.lastname: Kim
mesh_terms: D000818:Animals; D000081247:CSK Tyrosine-Protein Kinase; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D051379:Mice; D041681:NIH 3T3 Cells; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D013449:Sulfonamides / Q000494:pharmacology; D019061:src-Family Kinases; D020812:Receptor, trkC; D000097764:ETS Translocation Variant 6 Protein
chemical_list: D000081247:CSK Tyrosine-Protein Kinase; D007211:Indoles; D015514:Oncogene Proteins, Fusion; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; D051057:Proto-Oncogene Proteins c-akt; D034741:RNA, Small Interfering; D013449:Sulfonamides; D019061:src-Family Kinases; C484319:ETV6-NTRK3 fusion protein, human; D020812:Receptor, trkC; D000097764:ETS Translocation Variant 6 Protein; C416927:SU 6656; C000631346:CSK protein, human