This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ramos, D. M. Articles by Kramer, R. H. Search for Related Content PubMed PubMed Citation Articles by Ramos, D. M. Articles by Kramer, R. H.

Analysis of Integrin Receptors for Laminin and Type IV Collagen on Metastatic B16 Melanoma Cells¹

Departments of Stomatology and Anatomy, Schools of Dentistry and Medicine, University of California at San Francisco, San Francisco, California 94143

As tumor cells invade surrounding tissue, they adhere to various extracellular matrix components. Previously we reported that B16-BL6 melanoma cell adhesion to both basement membrane and purified protein substrates was blocked by antibody to ß₁-integrin adhesion receptors (R. H. Kramer et al., Cancer Res., 49: 393–402, 1989). In the present study we found, using immunofluorescent staining, that ß₁-integrin complexes were colocalized with vinculin in focal adhesion plaques on laminin, type IV collagen, and fibronectin substrates. To identify potential adhesion receptors on B16 cells, the cells were surface-labeled with ¹²⁵I, solubilized with detergent, and chromatographed on laminin-, type IV collagen-, and fibronectin-Sepharose columns. On laminin-Sepharose, an integrin heterodimer complex was eluted with EDTA that contained a ß₁ chain at M_r 120,000 and an subunit at M_r 140,000 (nonreduced). This complex was specific for laminin and failed to bind to collagen- or fibronectin-Sepharose columns. Immunoprecipitation with specific monoclonal antibody identified this complex as ₆ß₁ (VLA-6). Furthermore, monoclonal antibody to the ₆ß₁ complex effectively blocked the attachment of B16-BL6 cells to laminin but did not affect adhesion to fibronectin or type IV collagen. We recovered a different integrin complex from type IV collagen-Sepharose columns that was composed of a ß₁ chain and an chain of M_r 180,000 (nonreduced). This same complex also exhibited a weak affinity for laminin-affinity chromatography. The laminin-binding complex and the type IV collagen-binding complex were clearly distinct from the fibronectin-binding receptor and were not eluted by arginyl-glycyl-aspartate-containing peptides. The results suggest that the B16 melanoma cells express multiple integrin-related receptors that appear to mediate cell adhesion to basement membrane matrices.

¹ This work was supported by grants from the National Institute for Dental Research (K15-DE00242) and the National Cancer Institute (R01-CA33834).

² To whom requests for reprints should be addressed, at Box 0512, Room HSW 604, University of California at San Francisco, San Francisco, CA 94143-0512.

Received 3/27/89. Revised 7/21/89. Accepted 10/30/89.

This article has been cited by other articles:

				A. Magnifico, E. Tagliabue, S. Buto, E. Ardini, V. Castronovo, M. I. Colnaghi, and S. Menard Peptide G, Containing the Binding Site of the 67-kDa Laminin Receptor, Increases and Stabilizes Laminin Binding to Cancer Cells J. Biol. Chem., December 6, 1996; 271(49): 31179 - 31184. [Abstract] [Full Text] [PDF]

				H. Nakahara, M. Nomizu, S. K. Akiyama, Y. Yamada, Y. Yeh, and W.-T. Chen A Mechanism for Regulation of Melanoma Invasion. LIGATION OF alpha 6beta 1 INTEGRIN BY LAMININ G PEPTIDES J. Biol. Chem., November 1, 1996; 271(44): 27221 - 27224. [Abstract] [Full Text] [PDF]

				I. B.-H. N. B. Garty, and Uriel Z. Littauer and I. Bushkin-Harav Down-regulation of a 67-kDa YIGSR-binding Protein upon Differentiation of Human Neuroblastoma Cells J. Biol. Chem., June 2, 1995; 270(22): 13422 - 13428. [Abstract] [Full Text] [PDF]

				H Grenz, S Carbonetto, and S. Goodman Alpha 3 beta 1 integrin is moved into focal contacts in kidney mesangial cells J. Cell Sci., January 7, 1993; 105(3): 739 - 751. [Abstract] [PDF]