Enitociclib induces apoptosis by inhibition of RNA Pol II phosphorylation and oncogene expression in MM cells. Western blotting of NCI-H929 and OPM-2 MM cells treated with either DMSO (vehicle control; “–”) or 0.5 to 1 μM of enitociclib for up to 24 hours. Total cell lysates were prepared and analyzed by immunoblotting to detect levels of markers associated with apoptosis (total and cleaved PARP and caspase-3, Mcl-1, and Bim_EL), total and phosphorylated RNA Pol II CTD (S2/S5), and short half-life oncogene proteins c-Myc and PCNA. β-actin was used as a loading control. Molecular masses are indicated in kDa.