Fig. 3: Inhibition of HDAC6 enhances TMZ-induced DNA damage response.

A, B HR assay was performed after the treatment with DMSO or each HDAC6 inhibitor for 48 h at 2 μM in A and at indicated doses in B. Percentage of HR efficiency was calculated as the ratio of the indicated dosage of HDAC6 inhibitor treatment to DMSO treatment and quantified after three independent experiments. C U87MG cells were treated with 5 μM MPT0B291 or tubacin in the presence (100 μM) or absence of TMZ for 24 h. D A172 cells were treated with the indicated concentrations of MPT0B291 in the presence (100 μM) or absence of TMZ for 24 h. The protein levels of γH2AX, RAD51, CHEK1, HDAC6, Ac-tubulin, and tubulin were analyzed by western blotting (upper panels). Quantitative results (normalized to tubulin) of γH2AX from three independent experiments are shown (lower panels).