Influence of calcitriol on prostaglandin- and vitamin D-metabolising enzymes in benign and malignant breast cell lines

Background: Cyclooxygenase-2 (COX-2) is a potential molecular prognostic factor for breast cancer, and calcitriol [1,25(OH) ₂D ₃], the biologically active form of vitamin D, is a promising target in breast cancer therapy. Materials and Methods: The influence of calcitriol on the proliferation and the effects of calcitriol on the expression of prostaglandin- and vitamin D-metabolising enzymes were examined in benign and malignant breast cells. Results: Calcitriol inhibited the proliferation of MCF-10F and MCF-7 cells but not of invasive MDA-MB-231 cells and reduced the expression of COX-2 and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in the benign breast cell line MCF-10F. Furthermore, dysregulation in vitamin D-metabolising proteins was detected, especially in MDA-MB-231 cells. Conclusion: These results suggest dysregulation of vitamin D metabolism and a lack of a possible influence of calcitriol on the metabolism of prostaglandins in the malignant breast cell lines.