Figure 2.

MDR-1 gene silencing reduces MDR-1 proteins levels and renders MCF7/DOX cells sensitive to DOX. A) MCF7/DOX cells were treated with MDR-1 or scrambled siRNA oligos for 48 hrs. Protein lysates were prepared and analyzed using antibodies against MDR-1 and GAPDH as a protein load control. B) Cell killing was determined by MTT analysis of MCF7/DOX cells treated as above. The analysis was repeated three times and standard error of the mean is shown. A statistical analysis was performed using ANOVA with a post-hoc Tukey–Kramer test. MDR-1 siRNA + DOX is significantly different from control (P < 0.5).

Abbreviations: ANOVA, analysis of variance; DOX, doxorubicin; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; MDR-1, multiple drug resistance protein 1.