title: Activation of the FAK-src molecular scaffolds and p130Cas-JNK signaling cascades by alpha1-integrins during colon cancer cell invasion.
abstract: Increased src tyrosine kinase expression and activity has been associated with colon cancer cell invasion and survival. Several signaling pathways are involved in the oncogenic activation of src during the adenoma to carcinoma progression and cellular invasion. In the present study, the synthetic ether lipid analog ET-18-OMe was shown to promote invasion of HCT-8/S11 colon cancer cells into collagen type I through the concomitant activation of src by phosphorylation at Tyr416 (5-30 min) in alpha1-integrin immunoprecipitates containing the integrin binding proteins talin and paxillin, as well as the phoshorylated and activated forms of focal adhesion kinase (FAK) at Tyr397 (a FAK kinase activation signal), Tyr576 and Tyr861. This was associated with the lateral redistribution of alpha1-integrins in focal aggregates and persistent activation of the p130Cas/JNK pathways at 5-30 min, with the subsequent induction and activation of the matrix metalloproteinases MMP-2 and MMP-9 (2-12 h). These activated molecular scaffolds and signaling cascades were not observed in immunoprecipitates of alpha2- and beta1-integrins, and tetraspanin CD9, an invasion and metastasis suppressor linked to integrins and FAK signaling. Our data demonstrate that the lateral redistribution and clustering of alpha1-integrins results in the recruitment of the FAK/src motility-promoting signaling complex involved in cancer cell invasion. Disruption of this proinvasive pathway was accomplished by the dominant negative mutant of src (K295R, kinase dead), src pharmacological inhibitor (PP1) and alpha1-integrin function blocking antibodies. These findings support the notion that the alpha1-integrin- and src-dependent signalosome is a relevant therapeutic target against tumor progression in colon cancer patients.
authors.affiliation: Laboratory of Biochemical and Biomedical Research, Department of Chemistry, New Mexico Tech, Socorro, NM, USA.
authors.forename: Severine
authors.initials: S
authors.lastname: Van Slambrouck
authors.forename: Clara
authors.initials: C
authors.lastname: Grijelmo
authors.forename: Olivier
authors.initials: O
authors.lastname: De Wever
authors.forename: Erik
authors.initials: E
authors.lastname: Bruyneel
authors.forename: Shahin
authors.initials: S
authors.lastname: Emami
authors.forename: Christian
authors.initials: C
authors.lastname: Gespach
authors.forename: Wim F A
authors.initials: WF
authors.lastname: Steelant
mesh_terms: D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000473:pathology*; D050719:Crk-Associated Substrate Protein / Q000502:physiology*; D004789:Enzyme Activation; D051417:Focal Adhesion Kinase 1 / Q000502:physiology*; D006801:Humans; D039423:Integrin alpha1 / Q000502:physiology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D009361:Neoplasm Invasiveness; D010766:Phosphorylation; D019061:src-Family Kinases / Q000502:physiology*
chemical_list: D050719:Crk-Associated Substrate Protein; D039423:Integrin alpha1; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human; D019061:src-Family Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9