Modulation of differentiation-related responses in human colon carcinoma cells by protein kinase inhibitor H-7.

1-(isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7), a potent inhibitor of protein kinases, has been used as a tool to examine the role of protein kinases in a variety of cellular functions. Contingent on the cell type, H-7 has been reported either to inhibit or to promote differentiation. The biological effects of H-7 on human colon adenocarcinoma cells have not been reported. In this study we investigated the effects of H-7 on differentiation - related parameters such as cellular morphology, proliferation, the expression of carcinoembryonic antigen (CEA), fibronectin and cytokeratins in human adenocarcinoma cell lines HCT116 and SW480. H-7 induced pronounced morphological alterations in both cell lines. It induced fibronectin expression and down-modulated CEA expression and secretion in the SW480 cells, but not in the HCT116 cells. Expression of acidic keratins was not affected by H-7 treatment in both cell lines. However, the expression of basic keratins were down-modulated in the HCT116 cells and enhanced in the SW480 cells. These studies showed that the protein kinase inhibitor, H-7, modulated phenotypic properties in human colon adenocarcinoma cells. Alterations in phenotypic properties and their significance in regard to the induction of differentiation are discussed.