Correlated downregulation of VDR and CYP3A4 in colorectal cancer.

Abstract

The evidence obtained from experimental studies suggests the tumor-suppressive effects of vitamin D by controlling the differentiation, proliferation, and apoptosis in cancerous cells. Furthermore, the deregulation of genes involved in vitamin D metabolism has been reported in several types of cancer. In the present study, we investigated the expression level of vitamin D metabolic pathway genes, including VDR, CYP3A4, RXRα, and GC, in colorectal cancer (CRC) samples compared with the adjacent tissues by using quantitative RT-PCR. The results indicated significant downregulation of CYP3A4 and VDR genes in CRC tissues compared with the adjacent control tissues (p < 0.01). RXRA and GC expression levels did not show any significant alteration among the studied samples. Moreover, a positive correlation was observed between the expression level of CYP3A4 and VDR genes (p < 0.0001). ROC curve analysis also revealed the potential diagnostic power of CYP3A4 and VDR genes in CRC samples. Reduction in the expression of both CYP3A4 and VDR plays an important role in CRC due to the possible impairment in vitamin D metabolism. Further studies concerning the relationship between the expression of these genes and colorectal cancer pathogenesis and treatment are recommended.