Fig. 3.

The effects of 1,25α(OH)2D3 and CDA on the cell-cycle status and gene regulation. (A) Cell-cycle analysis of RWPE-1 cells measured by FACS analysis. Cells were treated with ligand ED₂₅ concentrations individually and in combination for 24h. Representative cell-cycle distributions are shown (upper panel), with subsequent quantification of three biological replicate populations (lower panel). Significant changes (determined by t-test) of cell population at any given cell cycle are noted, comparing additive results to those observed experimentally. (B) VDR candidate gene expression profile in RWPE-1 cells. Expression of known VDR-regulated genes (IGBFP3, CDKN1A) at different time points of treatment (4, 12, 24h) determined via Q-RT–PCR. The 1α,25(OH)₂D₃ (D3) and CDA were dosed individually and in combination at ED₂₅ concentrations and were compared with respective vehicle controls. Significant changes of gene expression between combination treatment and individual treatments (*D3, ^#CDA) are noted.