Figure 8

CRBP1 is a downstream target of retinoic acid receptor (RAR)γ. A) Immunoblotting analysis of CRBP1 protein in tumor lysates from 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carboxamido]benzoic acid (Am580)-responsive (Am580 R) and Am580-nonresponsive (Am580 NR) tumors. Results from three representative tumors from each experimental group are shown. Tubulin was used as a loading control. B) and C) Quantitative (Q)-PCR analysis of CRBP1 gene expression in normal mammary epithelial cells obtained from FVB mice transfected with RARγ or vector control and treated with 1 uM All-trans retinoic acid (ATRA) or vehicle control for 48 h. D) Primary mammary epithelial cells obtained from a normal FVB female mouse were isolated and used to generate a primary culture that was treated with each retinoid (100 nM Am580, 1 uM ATRA, 100 nMSR11253 and 60 nM BMS961) for 72 h., CRBP1 protein levels were determined by western blot analysis. Results shown are representative of three independent experiments. E) Chip analysis of lysates from normal FVB mammary epithelial cells treated or not with 1 μM ATRA for 48 h to examine interaction of RARγ with the CRBP1 gene promoter. Results presented are representative of three independent experiments done in triplicate.