Prevention of gene expression by inhibition of GPR30 with estriol. RT-PCR of (A) HCC1806 and (B) HCC70 Serum starved cells of TNBC cell lines (lane 1) were stimulated for 30 minutes with 10-8 M 17β-estradiol (lane 2) or pretreated with 10-4 M estriol (lane 3) and subsequently stimulated with 10-8 M 17β-estradiol (lane 4). mRNA was extracted, transcribed to cDNA and amplified by PCR using primers specific for c-fos (panel 1), cyclin D1 (panel 2) or aromatase (panel 3). L7, a ribosomal housekeeping gene, was amplified to prove the presence of equal amounts of RNA in each PCR reaction of the respective cell line (panel 4). Representative results of three separate experiments. (C) and (D) densitometric evaluation of RT-PCR results of c-fos, cyclin D1 and aromatase in HCC1806 cells (C) and HCC70 (D).