Abstract:

BACKGROUND: Studies have demonstrated that vitamin D receptor (VDR) induces CYP3A4 gene transcription and expression in tract, and the abnormity of VDR will change the quantity and quality of its protein and cause alteration of target genes transcription and expression or function in the downstream.
OBJECTIVE: To identify the effects of VDR Fok Ⅰ mutation on the transcription of CYP3A4 in intestinal tract HT-29 cells.
METHODS: Hepatic tissues were obtained from hepatolithus patients and constructed pcDNA3.1(-)B-myc/his h VDR eukaryotic expression vectors (wild type and Fok Ⅰ mutant). The HT-29 cells were transfected by using cell transfection technique and dual-luciferase report gene analytical system and treated by different concentrations of 1,25(OH)2VD3 (1, 10, and 100 nmol/L). The transcription of CYP3A4 in cultured HT-29 cells was observed.
RESULTS AND CONCLUSION: In transiently transfected HT-29 cells, the CYP3A4 luciferase activity of three concentrations (1, 10, 100 nmol/L) was increased respectively after 1,25(OH)2VD3 was added to cells for 24 hours, and there were significant differences between 1,25(OH)2VD3 group and the vehicle control group (P < 0.05), the luciferase activity from mutant VDR constructs was a little greater than wild VDR constructs, but there was no significant difference between the two VDR forms (P > 0.05). VDR Fok Ⅰ mutant could not significantly change the regulational capacity of wild type VDR on CYP3A4. The results revealed that vitamin D induces CYP3A4 expression via VDR. However, compared with wild type, the VDR Fok I mutant has no obvious difference on CYP3A4 expression.