Fig. 6
From: ABC-transporter upregulation mediates resistance to the CDK7 inhibitors THZ1 and ICEC0942
Chemotherapy-resistant cell lines are cross-resistant to CDK7 inhibitors. mRNA levels of ABCB1 (a) and ABCG2 (c) were examined in OVCAR8, NCI-ADRR, MCF7 and MCF7-MXR by qRT-PCR (error bars = SEM, n = 3). OVCAR8 and NCI-ADRR were incubated with EFFLUXX-ID dye and MCF7 and MCF7-MXR with Hoechst 33342, and the accumulation of intracellular fluorescence was measured by flow cytometry every 5 min for 30 min. The mean fluorescence intensity at time 0 and 30 min is shown for OVCAR8 vs. NCI-ADRR (b) and MCF7 vs. MCF7-MXR (d) (error bars = SEM, n = 3). NCI-ADRR (e) and MCF7-MXR (f) were treated with increasing concentrations of THZ1 or ICEC0942 for 48 h. Dose-response curves shown are from single experiments (error bars = SEM, n = 6). Mean growth is shown relative to that for vehicle (DMSO)-treated cells. Asterisks represent statistically significant differences (unpaired t-test, **P < 0.01, ****P < 0.0001)
