Id2, E12 and E47 dysregulate Notch3 expression in breast cancer cells. (A, B) The mRNA expression level of Id2 and Notch3 was analyzed by qRT-PCR in breast cancer cell lines. (C) Id2 and Notch3 protein levels were analyzed by western blot in breast cancer cell lines. (D, E) The mRNA expression level of E12 and E47 was analyzed by qRT-PCR in breast cancer cell lines. (F, G) Expression of Id2 and Notch3 mRNA and protein in Id2 overexpressing MDA-MB-231 cells were analyzed by qRT-PCR and western blot, respectively. (H, I) The expression of Id2 and Notch3 mRNA and protein in Id2 knock-down MCF-7 cells were analyzed by qRT-PCR and western blot, respectively. (J, K, L) The expression of E47 and Notch3 in MCF-7 cells was analyzed by qRT-PCR and western blot 48 h after transfection of pcDNA3-E47. (M, N, O) The expression of E12 and Notch3 in MCF-7 cells was analyzed by qRT-PCR and western blot 48 h after transfection of pCS2-E12.