Extracellular matrix regulates steady-state mRNA levels of the proliferation associated protein Ki-67 in endometrial cancer cells.

We investigated whether components of the extracellular matrix have the potential to regulate the proliferative activity of endometrial adenocarcinoma cells. Culturing of cells on the reconstituted basement membrane matrigel down-regulated the steady-state mRNA levels of the proliferation associated protein, Ki-67, in the endometrial adenocarcinoma cell lines HEC 1B(L) and Ishikawa after 48-96 h of culture on the matrix substrate. Proliferation of Ishikawa was stimulated again if cells were cultured on matrigel and challenged by proteins representing functional domains of tenascin-C, a mesenchymal glycoprotein. The fibronectin-type-III-like repeats 6-8 of tenascin-C were found to be the most potent. In summary, evidence is provided that components of both epithelial and stromal extracellular matrices can function as regulators of cell growth.