Functional differences between integrin alpha4 and integrins alpha5/alphav in modulating the motility of human oral squamous carcinoma cells in response to the V region and heparin-binding domain of fibronectin.
The high-affinity heparin-binding domain and the V region of fibronectin (FN) mediate invasion and migration of human oral squamous cell carcinoma (SCC) cells. We investigated the role of the alpha4, alpha5, and alphav integrin receptors--which are central to mediating interactions with these domains of FN--in regulating SCC cell migration. SCC cells expressed the alpha4, alpha5, and alphav integrin subunits on their surface, although alpha4 expression was low. Treatment with recombinant FN proteins containing an alternatively spliced V region (V+) and either an unmutated (H+) or a mutated, nonfunctional high-affinity heparin-binding domain (H-) increased expression of alpha5 and alphav and cell motility. Antisense alpha5 or alphav oligonucleotides inhibited cell motility stimulated by FN proteins, as did blocking antibodies to alpha5 or alphav. Blocking antibodies to alpha5 increased alphav and alpha4 levels, and blocking antibodies to alphav increased the levels of alpha5 and alpha4, without increasing cell motility. In contrast, an antisense alpha4 oligonucleotide and alpha4-blocking antibodies increased cell motility, especially migration stimulated by V+H+ and V+H- FN proteins. alpha4-Blocking antibodies alone increased motility, probably by inducing alpha5 and alphav expression. Transfection with alpha4 cDNA decreased cell motility and alpha5 and alphav expression. Thus, the increased motility induced by the FN protein is probably mediated by alphav and alpha5, whereas alpha4 downregulates this process in a transdominant fashion.
Zhang
Yan
Y
Department of Stomatology, School of Dentistry, University of California, San Francisco, CA 94102, USA.
Lu
Hai
H
Dazin
Paul
P
Kapila
Yvonne
Y
D001483:Base Sequence; D002294:Carcinoma, Squamous Cell / Q000503:physiopathology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology*; D017931:DNA Primers; D005353:Fibronectins / Q000502:physiology*; D005786:Gene Expression Regulation; D006801:Humans; D039441:Integrin alpha4 / Q000235:genetics / Q000502:physiology*; D039482:Integrin alpha5 / Q000235:genetics / Q000502:physiology*; D039564:Integrin alphaV / Q000235:genetics / Q000502:physiology*; D009062:Mouth Neoplasms / Q000503:physiopathology*; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection
D017931:DNA Primers; D005353:Fibronectins; D039482:Integrin alpha5; D039564:Integrin alphaV; D011994:Recombinant Proteins; D039441:Integrin alpha4