Effect of inhibitors on histone 3B phosphorylation. (A) OPM-2 or MM1.S cells were exposed to increasing concentrations of the ZK inhibitor, after which immunoblot was performed for expression of total histone 3B or phosphorylated histone 3B (on serine 10). (B-C) Similar immunoblot experiments were performed on OPM-2 and MM1.S cells exposed to increasing concentrations of VX-680. The experiments depicted in panels A-C were repeated 3 times with identical results.