VARIANTS OF INTEGRIN BETA-4 SUBUNIT IN HUMAN ENDOMETRIAL ADENOCARCINOMA CELLS - MEDIATORS OF ECM-INDUCED DIFFERENTIATION

The influence of extracellular matrix (ECM) on expression and function of integrins in carcinogenesis and differentiation is not well unders tood, but the importance of altered adhesion features for tumor develo pment and profession is obvious. Integrins as versatile molecules are mainly responsible for mediating cell-matrix interactions and transmem brane signal transduction. They are capable of transducing outside-in signals from ECM components or conversely to organize the matrix by in side-out signaling. In the study presented here, we report that the re constituted basement membrane, Matrigel(TM) which induces morphologica l and functional differentiation of the endometrial adenocarcinoma cel l Line HEC 1B(L), also regulates the expression of various forms of th e integrin beta 4 subunit. Furthermore, we were able to identify full- length isoforms with and without an altered cytoplasmic domain as well as truncated forms. Our findings suggest a regulatory role of integri n beta 4 isoforms and fragments in the process of in vitro differentia tion of HEC 1B(L).