A Novel Monoclonal Antibody to Human Laminin [alpha]5 Chain Strongly Inhibits Integrin-Mediated Cell Adhesion and Migration on Laminins 511 and 521

• Published in: PloS one Vol. 8; no. 1; p. e53648
• Main Authors: Wondimu, Zenebech, Omrani, Shahin, Ishikawa, Taichi, Javed, Fawad, Oikawa, Yuko, Virtanen, Ismo, Juronen, Erkki, Ingerpuu, Sulev, Patarroyo, Manuel
• Format: Journal Article
• Language: English
• Published: Public Library of Science 07.01.2013
• Subjects: Enzyme-linked immunosorbent assay; Gliomas; Integrins; Laminin; Monoclonal antibodies
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0053648

Laminins, a large family of [alpha][beta][gamma] heterotrimeric proteins mainly found in basement membranes, are strong promoters of adhesion and migration of multiple cell types, such as tumor and immune cells, via several integrin receptors. Among laminin [alpha] (LM[alpha]) chains, [alpha]5 displays the widest tissue distribution in adult life and is synthesized by most cell types. Here, we have generated and characterized five novel monoclonal antibodies (mAbs) to the human LM[alpha]5 chain to further study the biological relevance of [alpha]5 laminins, such as laminins 511 ([alpha]5[beta]1[gamma]1) and 521 ([alpha]5[beta]2[gamma]1). As detected by ELISA, immunohistochemistry, immunoprecipitation and Western blotting, each antibody displayed unique properties when compared to mAb 4C7, the prototype LM[alpha]5 antibody. Of greatest interest, mAb 8G9, but not any other antibody, strongly inhibited [alpha]3[beta]1/[alpha]6[beta]1 integrin-mediated adhesion and migration of glioma, melanoma, and carcinoma cells on laminin-511 and, together with mAb 4C7, on laminin-521. Accordingly, mAb 8G9 abolished the interaction of soluble [alpha]3[beta]1 integrin with immobilized laminins 511 and 521. Binding of mAb 8G9 to laminin-511 was unaffected by the other mAbs to the LM[alpha]5 chain but largely hindered by mAb 4E10 to a LM[beta]1 chain epitope near the globular domain of laminin-511. Thus, mAb 8G9 defines a novel epitope localized at or near the integrin-binding globular domain of the LM[alpha]5 chain, which is essential for cell adhesion and migration, and identifies a potential therapeutic target in malignant and inflammatory diseases.