HDAC9 and glioblastoma: Al-Awadhi et al. investigated largazole (56) (Figure 14B) to ascertainits potential as a brain-penetrant class I HDAC inhibitor prodrug.58 Largazole demonstrated in vitro anti-GBM efficacy coupled with BBB-penetrating ability, as evidencedby studies based on measuring the active species (concentration),largazole thiol, in the mouse brain.