Figure 1.

Tissue-selective regulation of aromatase mRNA by calcitriol. A, Calcitriol decreases total aromatase mRNA in BCa cells. Total aromatase mRNA levels were determined in BCa cells treated for 24 h with 0.1% ethanol vehicle (Veh) or calcitriol (Cal, 100 nm for MDA-MB 231 and 10 nm for all other cells). *, P < 0.05 and **, P < 0.01 compared with vehicle. B, Calcitriol decreases various promoter-specific aromatase transcript levels in BCa cells. The levels of promoter-specific aromatase transcripts were determined in MCF-7 cells treated as in A. *, P < 0.05 and **, P < 0.01 compared with vehicle. C, Calcitriol increases aromatase mRNA in human osteosarcoma and ovarian cancer cells. Total aromatase mRNA levels were measured in human osteosarcoma cells (MG-63 and SaoS-2) and human ovarian cancer cells (OVCAR-3 and SKOV-3) treated as in A. **, P < 0.01 and ***, P < 0.001 compared with vehicle. D, Calcitriol increases various promoter-specific aromatase transcript levels in osteosarcoma cells. MG-63 cells were treated as in A and the levels of various promoter-specific aromatase transcripts determined. *, P < 0.05 and **, P < 0.01 compared with vehicle. E and F, Calcitriol decreases aromatase expression in 3T3-L1 preadipocytes. 3T3-L1 mouse fibroblasts representing undifferentiated preadipocytes (E, Pre-diff) were treated with ethanol vehicle (Veh) or 10 nm (Cal) for 24 h, and aromatase mRNA was measured. The cultures were then exposed to a differentiation-inducing medium with and without calcitriol addition for the final 24 h and aromatase mRNA was measured (E, Post-diff). Aromatase mRNA levels are shown as a percent of vehicle-treated control in Pre-diff cells set at 100% (E). *, P < 0.05 compared with vehicle treatment in Pre-diff cells. AP2, PPAR-γ, and perilipin mRNA levels were measured before (Pre-diff) and after (Post-diff) the induction of differentiation of 3T3-L1 cells (F). Values are shown as a percent of levels in Pre-diff cells (control) set at 100%. *, P < 0.05 compared with Pre-diff.