BACKGROUND: Histone deacetylase (HDAC) inhibitors are promising antitumoral 
drugs. Currently there are no data regarding the comparison of different HDAC 
inhibitors on hepatoma cells.
MATERIALS AND METHODS: Hepatoma cells were incubated with the HDAC inhibitors 
MS-275, SAHA, FK901228 and trichostatin. Proliferation was assessed via BrdU 
incorporation and apoptosis rate via flow cytometry. Trichostatin, SAHA and 
MS-275 were applied in a rat hepatoma model.
RESULTS: The agents showed antiproliferative and pro-apoptotic effects time- and 
dose-dependently. SAHA and MS-275 were moderately effective at 10 μM, while 
trichostatin A and FK901228 showed higher potency. Caspases 3 and 8 were 
activated upon treatment with the drugs. The agents increased the acetylation 
rate. Hyperacetylation did not correlate with antitumoral efficacy. In vivo, 
SAHA was superior to MS-275 and trichostatin A.
CONCLUSION: The HDAC inhibitors were effective both in vitro and in vivo. The 
potency of SAHA and MS-275 was similar. In spite of differing affinity to the 11 
known HDACs, the agents induced comparable effects. These findings suggest that 
these agents have further antitumoral effects apart from HDAC inhibition.