Figure 4.
1 significantly down regulates ABCB1 mRNA. (a) Northern blotting analysis of HeLa MDR Tet-off cells grown in the absence (lanes 1-3) or presence of 1 mM 1 (lanes 4-6) for 24 hours (lanes 1 and 4), 48 hours (lanes 2 and 5) or 72 hours (lanes 3 and 6), prior to RNA extraction and northern blotting with an ABCB1 cDNA biotin labeled probe. (b) Quantitative analysis of the ABCB1 mRNA extracted from HeLa MDR Tet-off cells cultured for 8, 24 or 48 hours in the absence (line with triangles) or presence of 1 mM 1 (line with filled squares) prior to RNA extraction and Taqman Q-RT-PCR analysis. (c) Western blot of protein extracts from HeLa Tet-off MDR (P-gp expressing) cells treated with 0 mM 1 (lane 1), 0.1 mM (lane 2), 1 mM (lane 3) or 10 mM 1 (lane 4) for 24 hours prior to harvesting and Western blot analysis with the anti-P-gp antibody C219. GAPDH control was used to calibrate loading. (d) 1 strongly down-regulates the amount of MRP1 in MCF7/VP-16 cells. Cells were treated with 0 mM (lane 1), 0.1 mM (lane 2), 1 mM (lane 3) or 10 mM (lane 4) 1 for 72 hours prior to harvesting, Western blotting and analysis of the ABCC1/MRP1 protein levels with the primary antibody QCRL and a loading control anti-GAPDH antibody.