Vitamin D and miRNAs in cancer

Vitamin D is a steroid hormone that regulates mineral homeostasis, bone metabolism and many other physiological processes. The active metabolite of vitamin D, 1α, 25-dihydroxyvitamin D (1,25D(3)), has broad spectrum antitumor activities and potentiates the effects of a number of chemotherapeutic agents. 1,25D(3) exerts its anti-tumor effects mainly through genomic mechanisms involving the regulation of gene transcription through vitamin D response elements (VDREs). More recently, miRNAs have been shown to be regulated by 1,25D(3). miRNAs are short non-coding RNAs that post-transcriptionally modulate the expression of a wide range of genes. Therefore, they have important regulatory roles in the development and progression of many diseases including cancer. This review focuses on the regulation of miRNA expression by 1,25D(3) in cancer model systems and the contribution of the regulated miRNAs to the anti-tumor effect of 1,25D(3). In addition, the impact of miRNAs on 1,25D(3) signaling is discussed.