BASEMENT-MEMBRANE INDUCED-DIFFERENTIATION OF HEC-1B(L) ENDOMETRIAL ADENOCARCINOMA CELLS AFFECTS BOTH MORPHOLOGY AND GENE-EXPRESSION

In vitro studies of endometrial carcinogenesis have been hampered by d edifferentiation of the cells in culture. Using the endometrial carcin oma cell line HEC-1B(L), we aimed to establish and characterize cultur e conditions that preserve a more differentiated state of the tumor ce lls. HEC-1B(L) cells grown in a serum-free defined medium on plastic ( PL/SFDM) on top of a reconstituted basement membrane (Matrigel(TM), MG /SFDM) or in a thick layer of Matrigel showed pronounced morphological differentiation as compared with HEC-1B(L) cells cultured on plastic in a medium containing serum (PL/10% FCS). Features of differentiation included cuboidal to columnar cell shape and an increase of rough end oplastic reticulum in Matrigel cultures. Gene expression of HEC-1B(L) cells was studied by metabolic [S-35]methionine labeling and SDS-gel e lectrophoresis. HEC-1B(L) cells cultured in the presence of Matrigel s howed two additional secretory proteins approximately 31 kD and 77 kD in size. rt-PCR was used to screen cell cultures for the presence of e strogen receptor, progesterone receptor, and lactoferrin-mRNA, genes t ypically expressed by normal endometrial epithelium. We found no expre ssion of the estrogen receptor or progesterone receptor. Lactoferrin-m RNA was present under all culture conditions tested. Our results sugge st a regulatory role of the extracellular matrix for the differentiati on of the HEC-1B(L) cell line.