Methods: Ca9-22 cells were used in this study. In immunofluorescent analysis, acetylate histone H3 and actin filaments were detected by Alexa Fluor 488 and Alexa Fluor 588 phalloidin, respectively. The cell viability of HDACi treatment was measured by the WST-1 assay. The cell-cycle was analyzed by a flow cytometer. HDACi-treated Ca9-22 cells were cultured for 24 h and stained with Hoechst 33342. Apoptosis-related proteins, such as caspase-9, caspase-3, caspase-6, caspase-7, PARP, Lamin A were determined by western blotting analysis.
Results: Cell viability was significantly reduced by HDACi treatment in a dose-dependent manner. HDACi treatment increased the levels of acetylate histone H3, and led to an augmentation of the proportion of the cells in the sub G1 phase. An early DNA fragmentation was seen at 24 h after exposure to 100 nM HDACi. Western blotting analysis revealed that HDACi caused activation of apoptosis-related proteins.
Conclusion: HDACi treatment induced apoptosis in Ca9-22 cells, suggesting that HDACi might be an effective drug against cancer cells.