The small non-coding RNA landscape of prostate epithelium

Vitamin D, a hormone that acts through the nuclear vitamin D receptor (VDR), upregulates anti-tumorigenic microRNA in prostate epithelium. This may contribute to the lower levels of aggressive prostate cancer (PCa) in patients with high serum vitamin D. Expression of other small non-coding RNAs (ncRNAs) in prostate epithelium and their potential regulation by vitamin D are uncharacterized. Laser capture microdissection (LCM) followed by small-RNA sequencing was used to identify ncRNA in the prostate epithelium of tissues from a vitamin D-supplementation trial. We compared the expression profiles to small-RNA sequencing data from primary prostate epithelial cells and publically-available benign whole prostate. Application of LCM to isolate epithelium promoted sample homogeneity and captured more diversity in ncRNA species. An abundance of PIWI-interacting RNAs (piRNAs) was detected in normal prostate epithelium, which increased under high vitamin D conditions. Overall design: Small RNA from benign epithelium of four control prostates and four prostates containing a high concentration of vitamin D was sequenced. Small RNA from one primary prostate epithelial cell line treated with ethanol or 50 nM vitamin D (1,25D) was also sequenced.