Expression of prostaglandin- and vitamin D-metabolising enzymes in benign and malignant breast cells

Background: Cyclooxygenase-2 (COX-2) plays a crucial role in prognosis of malignancy and has been associated with carcinogenesis, particularly neoangiogenesis and tumor progression. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is described as a tumour suppressor in cancer. The antiproliferative effects of calcitriol [1,25(OH) ₂D ₃] mediated via the vitamin D receptor (VDR) render vitamin D a promising target in breast cancer therapy. Materials and Methods: The expression of prostaglandin (PG)-metabolizing enzymes, vitamin D-metabolising enzymes and VDR were determined in benign and malignant breast cell lines using western blot analysis. Results: We detected an inverse correlation between the two types of metabolism, a reduced VDR expression in the malignant breast cell lines, and therefore an insufficient induction of 24-hydroxylase in the malignant cells. Conclusion: We suggest the possibility of dysregulation of vitamin Dmetabolizing enzymes in malignant breast cell lines.