[Investigations on cell surface molecules expressed by human oral squamous carcinoma line cells HSC-3, LMF 4 and LMF 5, with metastatic potential].
Production and characterization of hemidesmosome-specific mouse monoclonal antibodies 3A1 and 8A12 raised against the oral squamous carcinoma line cells were previously reported. In this study, further investigations were carried out to characterize these antigens using those cells. Immunoaffinity-purified 3A1 antigen was identified as a 180kD glycoprotein [205kD under reduced conditions]. Acetate membrane electrophoresis of disaccharides originating from this antigen digested by chondroitinase ABC showed that this protein was associated with hyaluronate. Immunoprecipitates by 3A1 and 8A12 antibodies were composed of two bands: 180kD and 140kD [205kD and 125kD by reduction], and were similar to integrin alpha 6 beta 4 precipitated by monoclonal anti-alpha 6 subunit antibody. Immunoprecipitation-Western Blot analysis showed that the 140kD [125kD] protein precipitated by 3A1 and 8A12 was alpha 6 subunit and that the 180kD [205kD] beta 4 subunit. After the alpha 6 subunit was immunodepleted, only the 180kD [205kD] band was immunoprecipitated by 3A1 or 8A12. Both 3A1 and 8A12 blocked the adhesion of LMF5 cells to laminin. These data indicated that 3A1 and 8A12 recognized integrin beta 4 subunit and that integrin alpha 6 beta 4 functioned as a laminin receptor on these cells. It was suggested that hyaluronan detected in the 3A1 antigen was associated with two putative hyaluronan-binding motifs in the extracellular domain of the integrin beta 4 subunit.
Niinaka
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Y
Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tokyo Medical and Dental University.
D000818:Animals; D000911:Antibodies, Monoclonal; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D006801:Humans; D016023:Integrins / Q000032:analysis* / Q000502:physiology; D051379:Mice; D009062:Mouth Neoplasms / Q000473:pathology*; D009362:Neoplasm Metastasis; D011233:Precipitin Tests; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D016023:Integrins