Figure 4.

HDAC7 is downregulated by panobinostat and knockdown causes growth inhibition in bortezomib-sensitive and refractory lines. (A) RMPI-8226 and Kas6 were treated with 50 nM vorinostat or panobinostat for 12 h before the harvest of total RNA. HDAC7 expression was measured by RT-PCR. Expression of HDAC7 in sensitive or resistant RMPI-8226 and Kas6 cells treated with vorinostat or panobinostat was normalized to vehicle-treated RPMI-8226wt and Kas6wt, respectively. (B) RMPI-8226 and Kas6 were treated with 50 nM vorinostat or panobinostat for 12 h before harvesting for protein, and HDAC7 expression was measured by immunoblotting. (C) Peripheral blood mononuclear cells from a patient enrolled from a phase I/II newly diagnosed multiple myeloma clinical trial (Clinicaltrials.gov, number NCT01440582) before and after the first cycle treatment was harvested, and HDAC7 expression in PBMC was measured by immunoblotting. (D, E) RPMI-8226wt transfected with either vehicle or cas9 plasmid with sgRNA targeting HDAC7. HDAC7 after transfection was measured by immunoblotting. Cell growth was monitored by measuring the number of viable cells over the course of 96 h in (D). In addition, cell cycle distribution was determined by propidium iodide staining using flow cytometer in (E). ^*P < 0.05. ^**P < 0.01. HDAC: Histone deacetylase.