HDAC9 and central nervous system cancer: Viability of rat F98 glioma cells and human U251-MG glioblastoma cells was measured by MTS assay (CellTiter 96® AQueous One Solution Cell Proliferation Assay; Promega GmbH, Walldorf, Germany) after incubation with <50 μM BA3 or 50 μM reference HDAC inhibitors for 72 h.