Decreased RNA Polymerase II activity and RNA synthesis in transcriptional RP2i-treated KG1a cells. Un-manipulated KG1a cells and cells enriched for dormancy by rapamycin pre-treatment were cultured with chemotherapy drugs, each drug at its 48 hour IC50 concentration. (Daunorubicin was not included in this set of experiments, due to interference from its fluorescent properties). (A) Loss of serine 2-phosphorylated RNA Polymerase II (RP2S2) was measured after 6 hours’ incubation of proliferating and dormancy-enriched cells with chemotherapeutic agents. For comparisons against untreated controls ** signifies P < 0.01; * signifies P < 0.05. (B) RNA synthesis was measured by 20 μM 5-ethynyl uridine incorporation for the final hour of a six hour treatment with chemotherapeutic agents. For comparisons against untreated controls ** signifies P < 0.01; * signifies P < 0.05. (C) Apoptosis was measured using Annexin V after 18 hours. In each experiment datapoints indicate mean and SEM of at least 3 independent assays.