title: Epigenetic regulation of vitamin D hydroxylase expression and activity in normal and malignant human prostate cells.
abstract: It was previously suggested that the 25-Vitamin-D3-1alpha-hydroxylase (CYP27B1) is downregulated during human prostate tumor pathogenesis while the catabolic 25-Vitamin-D3-24-hydroxylase (CYP24) expression is increased. The latter could lead to resistance against the antimitotic, pro-differentiating activity of 1,25-dihydroxycholecalciferol. Our hypothesis was that regulation of Vitamin D hydroxylase expression during prostate tumor progression might be under epigenetic control. We demonstrate by real time RT-PCR that PNT-2 human normal prostate cells indeed possess CYP27B1, but are practically devoid of CYP24 mRNA, whereas DU-145 cancer cells have constitutive expression of CYP24, and very low levels of CYP27B1 mRNA. Treatment of PNT-2 cells with the methylation inhibitor 5-aza-2'-deoxycytidine together with the deacetylation inhibitor trichostatin A resulted in elevation of both CYP27B1 and CYP24 mRNA expression demonstrating that even in normal human prostate cells expression of Vitamin D hydroxylases may be under epigenetic control. In the DU-145 malignant cell line trichostatin A together with 5-aza-2'-deoxycytidine increased CYP27B1 mRNA expression to a smaller extent than in normal cells, however this resulted in a highly significant increase in 1alpha-hydroxylation capacity. This demonstrates for the first time that synthesis of 1,25-dihydroxycholecalciferol in human prostate tumors could be reinitiated by epigenetic regulators.
authors.affiliation: Department of Pathophysiology, Medical University of Vienna, A-1090 Vienna, Waehringerguertel 18-20, Austria.
authors.forename: Maya
authors.initials: M
authors.lastname: Khorchide
authors.forename: Daniel
authors.initials: D
authors.lastname: Lechner
authors.forename: Heide S
authors.initials: HS
authors.lastname: Cross
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D002117:Calcitriol / Q000096:biosynthesis; D002460:Cell Line; D045744:Cell Line, Tumor; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D044127:Epigenesis, Genetic; D006801:Humans; D008297:Male; D011467:Prostate / Q000201:enzymology* / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013250:Steroid Hydroxylases / Q000235:genetics* / Q000378:metabolism*; D065668:Vitamin D3 24-Hydroxylase
chemical_list: D018076:DNA, Complementary; D004273:DNA, Neoplasm; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D065668:Vitamin D3 24-Hydroxylase; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002117:Calcitriol