TRANSFECTION OF BETA(4) INTEGRIN SUBUNIT INTO A NEOPLASTIC KERATINOCYTE LINE FAILS TO RESTORE TERMINAL DIFFERENTIATION CAPACITY OR INFLUENCE PROLIFERATION

Loss of expression of specific integrins is a feature of poorly differ entiated oral squamous cell carcinomas (SCCs) and cell lines derived f rom them, In order to test whether there is a direct link between redu ced alpha(6) beta(4) integrin expression and abnormal keratinocyte gro wth and differentiation we 'repaired' an SCC line, H376, by transfecti on of the beta(4) integrin subunit, We analysed five independent beta( 4) transfectant clones and compared them with four empty vector contro l clones and with the parental cell line, Elevated cell surface expres sion of alpha(6) beta(4) was not correlated with changes in anchorage dependent or independent growth and was not sufficient to induce expre ssion of the terminal differentiation marker, involucrin. Introduction of the beta(4) integrin subunit did not have a major effect on cell a dhesion to laminin 1 or 5 and did not result in formation of stable an choring contacts. We conclude that loss of alpha(6) beta(4) is not dir ectly responsible for the abnormal behaviour of the H376 cell line.