HDAC1 and glioblastoma: Moreover, in human U87MG GBM cells and rat C6 glioma cells, CM combination consisting of 8-CPT-cAMP (C) and MS-275 (M) targeting histone deacetylases 1 and 3 (HDAC1 and HDAC3) induced marked morphologic phenotype characterized by shrinking cell bodies and long synapse-like structure (Fig. 1B).