Fenretinide increases the transcriptional activity of RARβ. Huh-7 cells were treated with fenretinide for 24 hours followed by ChIP assay. (A)RARβ and (B)CYP26A1 promoter fragments (harboring RARE) bound by RARβ were immunoprecipitated with a specific antibody against RARβ and amplified by PCR. Representative PCR results from two independent experiments were shown. The histograms depict the relative fold of PCR band intensity (after normalized to the corresponding input) between fenretinide treatment and DMSO treatment.