title: The interaction between caveolin-1 and Rho-GTPases promotes metastasis by controlling the expression of alpha5-integrin and the activation of Src, Ras and Erk.
abstract: Proteins containing a caveolin-binding domain (CBD), such as the Rho-GTPases, can interact with caveolin-1 (Cav1) through its caveolin scaffold domain. Rho-GTPases are important regulators of p130(Cas), which is crucial for both normal cell migration and Src kinase-mediated metastasis of cancer cells. However, although Rho-GTPases (particularly RhoC) and Cav1 have been linked to cancer progression and metastasis, the underlying molecular mechanisms are largely unknown. To investigate the function of Cav1-Rho-GTPase interaction in metastasis, we disrupted Cav1-Rho-GTPase binding in melanoma and mammary epithelial tumor cells by overexpressing CBD, and examined the loss-of-function of RhoC in metastatic cancer cells. Cancer cells overexpressing CBD or lacking RhoC had reduced p130(Cas) phosphorylation and Rac1 activation, resulting in an inhibition of migration and invasion in vitro. The activity of Src and the activation of its downstream targets FAK, Pyk2, Ras and extracellular signal-regulated kinase (Erk)1/2 were also impaired. A reduction in α5-integrin expression, which is required for binding to fibronectin and thus cell migration and survival, was observed in CBD-expressing cells and cells lacking RhoC. As a result of these defects, CBD-expressing melanoma cells had a reduced ability to metastasize in recipient mice, and impaired extravasation and survival in secondary sites in chicken embryos. Our data indicate that interaction between Cav1 and Rho-GTPases (most likely RhoC but not RhoA) promotes metastasis by stimulating α5-integrin expression and regulating the Src-dependent activation of p130(Cas)/Rac1, FAK/Pyk2 and Ras/Erk1/2 signaling cascades.
authors.affiliation: The Campbell Family Institute for Breast Cancer Research, University Health Network, Toronto, Ontario, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Arpaia
authors.forename: H
authors.initials: H
authors.lastname: Blaser
authors.forename: M
authors.initials: M
authors.lastname: Quintela-Fandino
authors.forename: G
authors.initials: G
authors.lastname: Duncan
authors.forename: H S
authors.initials: HS
authors.lastname: Leong
authors.forename: A
authors.initials: A
authors.lastname: Ablack
authors.forename: S C
authors.initials: SC
authors.lastname: Nambiar
authors.forename: E F
authors.initials: EF
authors.lastname: Lind
authors.forename: J
authors.initials: J
authors.lastname: Silvester
authors.forename: C K
authors.initials: CK
authors.lastname: Fleming
authors.forename: A
authors.initials: A
authors.lastname: Rufini
authors.forename: M W
authors.initials: MW
authors.lastname: Tusche
authors.forename: A
authors.initials: A
authors.lastname: Brüstle
authors.forename: P S
authors.initials: PS
authors.lastname: Ohashi
authors.forename: J D
authors.initials: JD
authors.lastname: Lewis
authors.forename: T W
authors.initials: TW
authors.lastname: Mak
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement; D002642:Chick Embryo; D050719:Crk-Associated Substrate Protein / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D039482:Integrin alpha5 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D008969:Molecular Sequence Data; D009362:Neoplasm Metastasis; D009374:Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D011485:Protein Binding; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000075024:rhoC GTP-Binding Protein; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D051242:Caveolin 1; D050719:Crk-Associated Substrate Protein; D039482:Integrin alpha5; D019061:src-Family Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; C512911:Rhoc protein, mouse; D018631:ras Proteins; D020741:rho GTP-Binding Proteins; D000075024:rhoC GTP-Binding Protein