Methods: HDAC activity in osteosarcoma cells was measured using HDAC activity assay Kit, and the histone acetylation was detected by Western Blotting analysis. The cell viability was evaluated by WST-1 assay when being treated with HDACi. The cell cycle was analyzed by flow cytometor. The fragmentation of nuclear was confirmed by Hoeachst staining. The expression of apoptosis-related proteins, caspase-7, caspase-9, PARP and Lamin A/C, were detected by Western Blotting analysis.
Result: The HDAC activity decreased and the histone acetylation was detected in ROS17/2.8 and Saos-2 cells treated with HDACi. In HDACi-treated Saos-2, the cell viability significantly decreased in does- and time-dependent manner. FACS analysis revealed that the proportion of sub G1 phase increased in Saos-2. Western Blotting analysis revealed that HDACi induced caspase-9 and -7 activity, and the cleavage of PARP and LaminA/C in Saso-2. The fragmentation of nuclear was detected on Saos-2 by Hoechst staining. On the other hands, ROS17/2.8 was not shown these significantly change by HDACi treatment.
Conclusion: The results indicated that HDACi induced apoptosis in Saos-2. The difference of cell viability between Saos-2 and ROS17/2.8 expression may be caused by the HDAC activity or by the difference of apoptosis-related proteins in each cell.