KN-93,a specific inhibitor of CaMKⅡ inhibits human hepatic stellate cell proliferation in vitro

AIM: To investigate the effects of KN-93, a CaMKⅡ selective inhibitor on cell proliferation and the expression of p53 or p21 protein in human hepatic stellate cells. METHODS: Human hepatic stellate cells (LX-2) were incubated with various concentrations (0-50 mmol/L) of KN-93 or its inactive derivative, KN-92. Cell proliferation was measured by CCK-8 assay, and the expression of two cell cycle regulators, p53 and p21, was determined by SDS-PAGE and Western blotting. RESULTS: KN-93 (5-50 mmol/L) decreased the proliferation of human hepatic stellate cells in a dose- dependent manner from 81.76% (81.76% ± 2.58% vs 96.63% ± 2.69%, P < 0.05) to 27.15% (27.15% ± 2.86% vs 96.59% ± 2.44%, P < 0.01) after 24 h treatment. Incubation of 10 mmol/L KN-93 induced the cell growth reduction in a time-dependent manner from 78.27% at 8 h to 11.48% at 48 h. However, KN-92, an inactive derivative of KN-93, did not inhibit cell proliferation effectively. Moreover, analysis of cell cycle regulator expression revealed that KN-93 rather than KN-92 reduced the expression of p53 and p21.