Analysis of the vitamin D system in basal cell carcinomas (BCCs).
Using real-time PCR (LightCycler) and immunohistochemistry, we have analyzed expression of key components of the vitamin D system in basal cell carcinomas (BCCs) and normal human skin (NS). Increased VDR-immunoreactivity was demonstrated in BCCs using a streptavidin-peroxidase technique. RNA expression of vitamin D receptor (VDR) and of main enzymes involved in synthesis and metabolism of calcitriol (vitamin D-25-hydroxylase [25-OHase], 25-hydroxyvitamin D-1alpha-hydroxylase [1alpha-OHase], 1,25-dihydroxyvitamin D-24-hydroxylase [24-OHase]) was detected in BCCs and NS. Expression levels were determined as ratios between target genes (VDR, 1alpha-OHase, 25-OHase, 24-OHase) and the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as internal control. Median of mRNA ratios for VDR/GAPDH (BCCs: 16.54; NS: 0.00021), 1alpha-OHase/GAPDH (BCCs: 0.739; NS 0.000803) and 24-OHase/GAPDH (BCCs: 0.00585; NS 0.000000366) was significantly (Wilcoxon-Mann-Whitney U-test) elevated in BCCs. In contrast, median of mRNA ratio for 25-OHase/GAPDH (BCCs: 0.17; NS: 0.016) was not significantly altered in BCCs as compared to NS. Additionally, we report for the first time expression of 1alpha-OHase splice variants in BCCs and NS, that were detected using conventional RT-PCR. In conclusion, our findings provide supportive evidence for the concept that endogeneous synthesis and metabolism of vitamin D metabolites as well as VDR expression may regulate growth characteristics of BCCs. New vitamin D analogs that exert little calcemic side effects, their precursors, or inhibitors of 24-OHase may offer a new approach for the prevention or therapy of BCCs. The function of alternative transcripts of 1alpha-OHase that we describe here for the first time in BCCs and NS and their effect on activity level has to be investigated in future experiments.
Mitschele
Tanja
T
Universitäts-Hautklinik, Universitätshautkliniken des Saarlandes, Homburg, Germany.
Diesel
Britta
B
Friedrich
Michael
M
Meineke
Viktor
V
Maas
Ruth M
RM
Gärtner
Barbara C
BC
Kamradt
Jörn
J
Meese
Eckart
E
Tilgen
Wolfgang
W
Reichrath
Jörg
J
D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics; D017398:Alternative Splicing; D001483:Base Sequence; D002280:Basal Cell Carcinoma / Q000235:genetics / Q000378:metabolism*; D016022:Case-Control Studies; D053493:Cholestanetriol 26-Monooxygenase; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism*; D013250:Steroid Hydroxylases / Q000235:genetics; D014807:Vitamin D / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D065668:Vitamin D3 24-Hydroxylase
D012333:RNA, Messenger; D012334:RNA, Neoplasm; D018167:Receptors, Calcitriol; D014807:Vitamin D; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; C506831:CYP27A1 protein, human; D053493:Cholestanetriol 26-Monooxygenase; D065668:Vitamin D3 24-Hydroxylase; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase