Figure 6. BRCA1 silencing enhances IGF-I signaling and effects on ACCA.

(A, B) MCF7 breast cancer cells were transfected with BRCA1 siRNA or control siRNA for 48 hours before stimulation with 25 ng/ml IGF-I for 30 minutes. (A) Representative blots of western blotting analysis of p-ACCA (S⁷⁹) and total ACCA are shown. The graph shows densitometry analyses of p-ACCA (S⁷⁹) normalized to total ACCA. Each bar represents mean ± S.E.M. of three independent experiments. ^*p < 0.05, ^**p < 0.01 and ^***p < 0.001, one-way ANOVA. (B) UBR60-bcl2 cells with or without 1 mg/ml tetracycline and (C) MCF7 cells transfected with control siRNA or BRCA1 siRNA were treated with increasing doses (0–200 ng/ml) of IGF-I for 24 hours. The cells were pulsed with [3H]-labelled thymidine (1 μCi) 4 hours before the end of the experiment. The radioactive label was precipitated with trichloracetic acid, solubilised with sodium hydroxide and the signal was detected using liquid scintillation counter. The experiments were repeated 3 times and results are expressed as percentage increase for treatment over control. The graphs represent mean ± S.E.M. of three independent experiments.