Class I/IIb- but not class IIa-HDAC inhibitors potently inhibit metabolic activity of
amplified medulloblastoma (MB) cells in vitro. a The metabolic activity of MYC amplified medullobastoma cells HD-MB03, MED8A, D458 (yellow) is potently inhibited by class I/IIb HDACi vorinostat and HDAC1,2,3 selective MS275, but not by class IIa HDACi MAZ1863 and MAZ1866, each after 72 h of treatment. The metabolic activity of MYC non-amplified MB cells UW228-2, DAOY, ONS76 (red) is inhibited only at very high concentrations. b EC50 values of vorinostat and MS-275 are significantly lower for MYC amplified cell lines, and are close to (MS-275) or below (vorinostat) published plasma concentrations clinically achievable in patients (dashed lines).