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J Steroid Biochem Mol Biol. 2016 Jan;155(Pt A):85-93. doi: 10.1016/j.jsbmb.2015.09.021. Epub 2015 Sep 15.

Epigenetic regulation of steroid inactivating UDP-glucuronosyltransferases by microRNAs in prostate cancer.

Author information

1
Pharmacogenomics Laboratory, Centre Hospitalier Universitaire (CHU) de Québec Research Center, and Faculty of Pharmacy, Laval University, G1V 4G2 Quebec, Canada.
2
CHU de Québec Research Center, Faculty of Medicine, Laval University, Québec, Canada.
3
Pharmacogenomics Laboratory, Centre Hospitalier Universitaire (CHU) de Québec Research Center, and Faculty of Pharmacy, Laval University, G1V 4G2 Quebec, Canada. Electronic address: chantal.guillemette@crchul.ulaval.ca.

Abstract

Androgens play a central role in prostate cancer progression. Systemic and local androgen bioavailability is controlled by UDP-glucuronosyltransferases conjugating enzymes (UGT), namely UGT2B15, UGT2B17 and UGT2B28. Reporter vector assays in HEK293 cells initially validated in silico-predicted regulatory potential of candidate miRNAs to target UGT transcripts, including miR-376c, miR-409 and miR-494 for UGT2B17, miR-331-5p and miR-376c for UGT2B15 while none were efficient for UGT2B28. miR-376c was shown as the most effective to downregulate UGT2B15 and UGT2B17 through interactions with a site conserved in both UGTs. Ectopic miR-376c expression in prostate cancer cells significantly reduced UGT2B15 and UGT2B17 expression (>32%; P<0.005) with a consequent decrease in dihydrotestosterone glucuronidation (-37%; P<0.001). Consistent with reduced androgen inactivation, ectopic expression of miR-376c changed expression of androgen responsive genes and enhanced cell proliferation with no effect on androgen receptor levels. Sustaining a role of miR-376c in the regulation of androgen-inactivating UGTs, its expression was significantly downregulated in prostatic tumors and further reduced in metastases (P<0.0001), whereas the opposite was observed for UGT2B15/17 (P=0.031). In high-grade tumors (Gleason ≥8), UGT2B15/17 and miR-376c were inversely correlated (r=-0.557; P=0.048) with also a significant relationship in metastases (r=-0.747; P=0.003). In line with a modification in androgen bioavailability, PSA mRNA levels were also negatively correlated to those of UGT2B15/17 (r=-0.573; P=0.01) but positively linked to levels of miR-376c (r=0.577; P=0.039). This study reveals that the androgen-inactivating UGT2B15 and UGT2B17 genes are direct targets of miR-376c and thus may influence steroid metabolism during prostate cancer progression.

KEYWORDS:

Androgen; Cancer progression; Prostate cancer; UDP-glucuronosyltransferase; miRNA

PMID:
26385605
DOI:
10.1016/j.jsbmb.2015.09.021
[Indexed for MEDLINE]

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