Fig. 2

HDAC inhibitors AR-42 and SAHA induce apoptosis of osteosarcoma cells. a Dose-dependent increase of apoptosis in OS cells treated with AR-42 or SAHA as determined by analysis of cell cycle profiles by flow cytometry. Cells were exposed to DMSO, AR-42, or SAHA at the indicated concentrations for 48 h. The percentage of propidium iodide stained sub G1 cells is shown. Representative data from three independent experiments are presented. *p < 0.01, **p < 0.005, ***p < 0.0001. b Quantitation of caspase-3/7 enzymatic activity in OS cells treated with AR-42. OS cells were exposed to DMSO, AR-42, or SAHA at the indicated concentrations for 48 h. Caspase-3/7 enzymatic activity was determined using the SensoLyte® Homogeneous AMC Caspase-3 Assay Kit. *p < 0.01, **p < 0.005. c Dose-dependent effect of AR-42 on fragmented nucleosome accumulation in treated OS cells. OS cells were exposed to DMSO, AR-42, or SAHA at the indicated concentrations for 48 h. Fragmented cytoplasmic nucleosomal DNA was detected by Cell Death Detection ELISA Kit. *p < 0.001, **p < 0.0001. d Western blot analysis of apoptotic markers. OS cells were exposed to AR-42 or SAHA at the indicated concentrations for 48 h. Protein lysates were generated and separated by SDS-PAGE and Western blotting for caspase-3, Bcl-xL, and α-tubulin was performed