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 differentiated oral squamous cell carcinomas (SCCs) and cell lines derived from them, In order to test whether there is a direct link between reduced alpha(6) beta(4) integrin expression and abnormal keratinocyte growth and differentiation we 'repaired' an SCC line, H376, by transfection of the beta(4) integrin subunit, We analysed five independent beta(4) transfectant clones and compared them with four empty vector control clones and with the parental cell line, Elevated cell surface expression of alpha(6) beta(4) was not correlated with changes in anchorage dependent or independent growth and was not sufficient to induce expression of the terminal differentiation marker, involucrin. Introduction of the beta(4) integrin subunit did not have a major effect on cell adhesion to laminin 1 or 5 and did not result in formation of stable anchoring contacts. We conclude that loss of alpha(6) beta(4) is not directly responsible for the abnormal behaviour of the H376 cell line.