Vitamin D-24-hydroxylase in benign and malignant breast tissue and cell lines.
Tissue-specific expression of 25-hydroxyvitamin D-1alpha-hydroxylase (1alpha-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.
Fischer
D
D
Klinik für Frauenheilkunde und Geburtshilfe, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, D-23562 Lübeck, Germany. dorothea.fischer@uk-sh.de
Becker
S
S
Cordes
T
T
Bücker
B
B
Diedrich
K
K
Friedrich
M
M
Salehin
D
D
Thill
M
M
D000328:Adult; D000368:Aged; D017398:Alternative Splicing; D001483:Base Sequence; D001940:Breast / Q000166:cytology / Q000201:enzymology*; D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D002460:Cell Line; D045744:Cell Line, Tumor; D017931:DNA Primers; D005260:Female; D006801:Humans; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D013250:Steroid Hydroxylases / Q000235:genetics / Q000378:metabolism*; D065668:Vitamin D3 24-Hydroxylase
D017931:DNA Primers; D013250:Steroid Hydroxylases; D065668:Vitamin D3 24-Hydroxylase