title: Alphavbeta3 integrin and cofilin modulate K1735 melanoma cell invasion.
abstract: Cytoskeletal reorganization is partially mediated through cofilin, an actin assembly regulatory protein. Cofilin activity is modulated by reversible phosphorylation at Ser3. In this study, using K1735 murine melanoma cells, we examined the relationship between beta3-integrin expression, phosphorylation of cofilin, and metalloproteinase production. The levels of phosphorylated cofilin were 10-fold higher in cells expressing alphavbeta3 than in alphavbeta3-negative cells when plated on vitronectin for 30 min. However, by 60 min, phosphorylation of cofilin was greater in the beta3-negative cells. Expression of the wild type (WT) or non-phosphorylatable cofilin (A3 mutant) increased melanoma cell migration on vitronectin and invasion through a reconstituted basement membrane. Expression of a pseudophosphorylated, poorly active cofilin (E3 mutant) reduced cell motility. Expression of active cofilin accelerated the phosphorylation of FAK at Y397 and at Y576, strongly implicating cofilin as a mediator of cell signaling. The expression of MT1-MMP and MMP2 was also increased by expression of wild type or A3 cofilin. A 50% reduction of both enzymes was observed by the expression of the E3 cofilin. Overexpression of non-phosphorylatable cofilin was sufficient to induce the expression of MT1-MMP and MMP2 in the beta3-negative M2Tbeta3 cells. Interestingly, the invasion of M2Tbeta3 cells could be sustained by overexpression of cofilin A3. These results suggest that the integrin alphavbeta3 and cofilin together regulate K1735 melanoma cell invasion.
authors.affiliation: Department of Orofacial Sciences, University of California at San Francisco, Box 0512, San Francisco, CA 94143-0512, USA.
authors.forename: Dongmin
authors.initials: D
authors.lastname: Dang
authors.forename: James R
authors.initials: JR
authors.lastname: Bamburg
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Ramos
mesh_terms: D051339:Actin Depolymerizing Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D051338:Cofilin 1 / Q000235:genetics; D024042:Collagen Type I / Q000494:pharmacology; D003598:Cytoskeletal Proteins; D016373:DNA, Antisense / Q000235:genetics; D004151:Dipeptides / Q000494:pharmacology; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D022001:Focal Adhesions / Q000187:drug effects; D039302:Integrin alphaVbeta3 / Q000235:genetics / Q000502:physiology*; D053511:Matrix Metalloproteinase 14; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases / Q000378:metabolism; D053504:Matrix Metalloproteinases, Membrane-Associated; D008545:Melanoma / Q000473:pathology / Q000503:physiopathology; D051379:Mice; D009154:Mutation; D010750:Phosphoproteins / Q000235:genetics; D010766:Phosphorylation / Q000187:drug effects; D011480:Protease Inhibitors / Q000494:pharmacology; D014162:Transfection; D019096:Vitronectin / Q000494:pharmacology; D014981:Xenopus; D029867:Xenopus Proteins / Q000235:genetics
chemical_list: D051339:Actin Depolymerizing Factors; D000911:Antibodies, Monoclonal; D051338:Cofilin 1; D024042:Collagen Type I; D003598:Cytoskeletal Proteins; D016373:DNA, Antisense; D004151:Dipeptides; D039302:Integrin alphaVbeta3; D061965:Matrix Metalloproteinase Inhibitors; C507096:Mmp14 protein, mouse; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D010750:Phosphoproteins; D011480:Protease Inhibitors; D019096:Vitronectin; C098933:XAC1 protein, Xenopus; D029867:Xenopus Proteins; D051417:Focal Adhesion Kinase 1; C496051:Ptk2 protein, mouse; D020782:Matrix Metalloproteinases; D053504:Matrix Metalloproteinases, Membrane-Associated; D020778:Matrix Metalloproteinase 2; D053511:Matrix Metalloproteinase 14