25-hydroxyvitamin D3-1alpha-hydroxylase expression in normal and malignant human colon. |
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Authors: | Giovanna Bises Enik? Kállay Tina Weiland Friedrich Wrba Etienne Wenzl Elisabeth Bonner Stefan Kriwanek Peter Obrist Heide S Cross |
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Affiliation: | Department of Pathophysiology, Medical University of Vienna, Waehringerguertel 18-20, A-1090 Vienna, Austria. |
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Abstract: | 1,25-dihydroxyvitamin D(3) has anti-mitotic, pro-differentiating, and pro-apoptotic activity in tumor cells. We demonstrated that the secosteroid can be synthesized and degraded not only in the kidney but also extrarenally in intestinal cells. Evaluation of 1,25-dihydroxyvitamin D(3)-synthesizing CYP27B1 hydroxylase mRNA (real-time PCR) and protein (immunoblotting, immunofluorescence) showed enhanced expression in high- to medium-differentiated human colon tumors compared with tumor-adjacent normal mucosa or with colon mucosa from non-cancer patients. In high-grade undifferentiated tumor areas expression was lost. Many cells co-expressed CYP27B1 and the vitamin D receptor. We suggest that autocrine/paracrine antimitotic activity of 1,25-dihydroxyvitamin D(3) could prevent intestinal tumor formation and progression. |
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