Fig. 6: Sp1 regulates DDR gene expression and impairs MPT0B291-induced DNA damage.

A U87MG cells were treated with DMSO or 10 μM MPT0B291 following transfection with GFP or GFP-Sp1 plasmid. One day after treatment, the mRNA expression of GEN1 (a), EXO1 (b), TDG (c), NEIL3 (d), RAD54L (e), and DDB2 (f) in cells was analyzed by qPCR. Quantitative results (normalized to GAPDH) from five independent experiments are shown. B A172 cells were transfected with GFP or GFP-Sp1, and treated with the indicated dosage of MPT0B291 for 24 h. The protein levels of GFP-Sp1, Sp1, GFP (a), γH2AX and tubulin (b) were analyzed by western blotting. Quantitative result (normalized to tubulin) of γH2AX from three independent experiments is shown (lower panel). C Forest plots showing hazard ratios for the risk of death in patients with low-grade and high-grade glioma having higher expression of the indicated gene(s). The lines on both sides denote 95% confidence intervals. All the original data (Kaplan–Meier curve) were obtained from PROGgeneV2 database [51] (Supplementary Fig. S6). Hazard ratios above one indicate a poor outcome. D Schematic diagram shows that MPT0B291 induces DNA damage and cell death through the HDAC6/Sp1-mediated DDR gene regulation.