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High levels of PIWI‐interacting RNAs are present in the small RNA landscape of prostate epithelium from vitamin D clinical trial specimens
Author(s) -
Baumann Bethany,
Lugli Giovanni,
Gao Shang,
Zenner Morgan,
n Larisa
Publication year - 2019
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/pros.23789
Subject(s) - biology , prostate , prostate cancer , calcitriol receptor , non coding rna , rna , epithelium , cancer research , vitamin d and neurology , genetics , gene , endocrinology , cancer
Background Vitamin D, a hormone that acts through the nuclear vitamin D receptor (VDR), upregulates antitumorigenic microRNA in prostate epithelium. This may contribute to the lower levels of aggressive prostate cancer (PCa) observed in patients with high serum vitamin D. The small noncoding RNA (ncRNA) landscape includes many other RNA species that remain uncharacterized in prostate epithelium and their potential regulation by vitamin D is unknown. Methods Laser capture microdissection (LCM) followed by small‐RNA sequencing was used to identify ncRNAs in the prostate epithelium of tissues from a vitamin D‐supplementation trial. VDR chromatin immunoprecipitation‐sequencing was performed to identify vitamin D genomic targets in primary prostate epithelial cells. Results Isolation of epithelium by LCM increased sample homogeneity and captured more diversity in ncRNA species compared with publicly available small‐RNA sequencing data from benign whole prostate. An abundance of PIWI‐interacting RNAs (piRNAs) was detected in normal prostate epithelium. The obligate binding partners of piRNAs, PIWI‐like (PIWIL) proteins, were also detected in prostate epithelium. High prostatic vitamin D levels were associated with increased expression of piRNAs. VDR binding sites were located near several ncRNA biogenesis genes and genes regulating translation and differentiation. Conclusions Benign prostate epithelium expresses both piRNA and PIWIL proteins, suggesting that these small ncRNA may serve an unknown function in the prostate. Vitamin D may increase the expression of prostatic piRNAs. VDR binding sites in primary prostate epithelial cells are consistent with its reported antitumorigenic functions and a role in ncRNA biogenesis.