TY - JOUR T1 - Vitamin D-24-Hydroxylase in Benign and Malignant Breast Tissue and Cell Lines JF - Anticancer Research JO - Anticancer Res SP - 3641 LP - 3645 VL - 29 IS - 9 AU - D. FISCHER AU - S. BECKER AU - T. CORDES AU - B. BÜCKER AU - K. DIEDRICH AU - M. FRIEDRICH AU - D. SALEHIN AU - M. THILL Y1 - 2009/09/01 UR - http://ar.iiarjournals.org/content/29/9/3641.abstract N2 - Tissue-specific expression of 25-hydroxyvitamin D-1α-hydroxylase (1α-OHase) and vitamin D-hydroxylase (24-OHase) may act as the pivotal link between 25-hydroxyvitamin D3 (25(OH)D3) serum levels and the anticancer effects of 1,25-dihydoxyvitamin D3 (1,25(OH)2D3) and alternative splicing of the enzymes may regulate their biological function. The expression of 24-OHase in cells and breast tissue was investigated and its splice variants were detected. The expression of 24-OHase RNA and protein was assessed by RT-PCR followed by Western blot. The expression of 24-OHase was reduced by about 57% in MCF-7 breast cancer cells, compared to MCF-10F benign breast cells. In the Western blot, a signal at 56 kDa was found and further bands were detected at 42 and 44 kDa. In the breast cancer tissue, the expression of 24-OHase was reduced by about 58% compared to benign tissue. However, in the Western blot, only one signal was found in the benign tissue at 56 kDa, while in malignant tissue, a further band was detected at 40 kDa. Alternative splicing of 24-OHase may lead to a catalytically dysfunctional enzyme and may lead to less reduction of the target protein. ER -