HDAC9 and central nervous system cancer: To examine whether MPT0B291 inhibits HDACs on glioma cells, we conducted HDAC activity assays (Figure 1B-C) and confirmed by the expression of acetyl-tubulin (a consequence of cytoplasmic inhibition) and acetyl-histone H3 (a consequence of nuclear inhibition) in C6 glioma cells (Figure 1D).