Vitamin D, Calcidiol and Calcitriol Regulate Vitamin D Metabolizing Enzymes in Cervical and Ovarian Cancer Cells

The vitamin D metabolizing enzymes 25-, 1α- and 24-hydroxylase are expressed in malignant cells of the cervix and the ovaries. The aim of this study was to obtain further information about the regulation of the aforementioned enzymes by vitamin D, calcidiol and calcitriol in cervical and ovarian cancer. The human cervical adenocarcinoma cell line HeLa and the human ovarian adenocarcinoma cell line OVCAR-3 were incubated with vitamin D, calcidiol and calcitriol. The influence of vitamin D and its metabolites on the expression of 25-, 1α- and 24-hydroxylase was assessed by real-time RT-PCR. Calcitriol significantly increased the 24-hydroxylase mRNA levels in HeLa and OVCAR-3 cells. The expression of 25- and 1α-hydroxylase was not regulated in a statistically significant manner. These results suggest that in HeLa as well as OVCAR-3 cell lines, the metabolism of vitamin D is regulated via the expression of the catabolizing 24-hydroxylase.