Dose-dependent inhibition of metabolic activity by valproic acid, SAHA, abacavir, retinoic acid, and resveratrol. Metabolic activity of three medulloblastoma cell lines was measured by WST-1 assay after treatment with the indicated modulators for three days. Raw values were normalized to untreated control. Data are presented as mean ± SEM from at least three independent experiments done in triplicates. IC 30 values, depicted as black lines, indicate concentrations with 30-percent inhibition of metabolic activity.