Antitumor activity of Chidamide in hepatocellular carcinoma cell lines.

Chidamide, the structural analog of MS-275, is a novel and promising histone deacetylase (HDAC) inhibitor for use in cancer therapy. To investigate its effects on cancer cell growth, MTT assay was performed in 10 human cancer cell lines. The data showed that the IC50 of Chidamide ranged from 1 to 13 mu M, which was comparable to that of MS-275 in half of the tested cell lines. Furthermore, the growth curve indicated that cell growth was gradually inhibited with an increase in Chidamide dosage, and the inhibition was reversed after drug removal in two hepatocelluclar carcinoma cell lines, BEL-7402 and HCC-9204. To determine cell cycle and apoptosis, FACS was carried out in the BEL-7402 and HCC-9204 cells treated with Chidamide. A decrease in the cell population at S phase and an increase in the cell population at G1 phase occurred in a dose-dependent manner. In addition, Chidamide induced apoptosis and up-regulated p21 mRNA expression. These results suggest that Chidamide may arrest the cell cycle and inhibit the growth of hepatocellular carcinoma cells through up-regulation of p21. Further studies are required to clarify the antitumor activity of Chidamide in vivo and its mechanism in anticancer therapy.