Inhibitory effects of transforming growth factor-β on laminin production and growth exhibited by endoderm-like cells derived from embryonal carcinoma cells

Abstract

Abstract Previous studies have shown that two mouse embryonal carcinoma (EC) cell lines do not express cell surface receptors for transforming growth factor type-β (TGF-β) until they are induced to differentiate. To understand the effects of TGF-β in this model system, we have examined the effects of TGF-β on parietal endoderm-like cells derived from EC cells. We have determined that TGF-β exerts three effects on these cells. TGF-β inhibits proliferation of the parietal endoderm-like cells, and this occurs even in the presence of growth factors that stimulate their proliferation. TGF-β also alters the morphology of the parietal endoderm-like cells by increasing their spreading. Moreover, the morphological effect of TGF-β is observed in the presence of dibutyryl cyclic AMP (dbcAMP), which reduces the spreading of these cells. Lastly, TGF-β, but not other growth factors, decreases the production of laminin by the parietal endoderm-like cells. This was unexpected since TGF-β has been shown to increase the production of extracellular matrices in other systems. Thus, our findings indicate that parietal endoderm-like cells provide a useful system for broadening the study of TGF-β. Furthermore, our findings provide additional support for the possibility that TGF-β plays important roles during the early stages of mammalian development.