@article {Dluzen182, author = {Douglas F. Dluzen and Aimee K. Sutliff and Gang Chen and Christy J. W. Watson and Faoud T. Ishmael and Philip Lazarus}, title = {Regulation of UGT2B Expression and Activity by miR-216b-5p in Liver Cancer Cell Lines}, volume = {359}, number = {1}, pages = {182--193}, year = {2016}, doi = {10.1124/jpet.116.235044}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {The UDP-glucuronosyltransferase (UGT) 2B enzymes are important in the detoxification of a variety of endogenous and exogenous compounds, including many hormones, drugs, and carcinogens. Identifying novel mechanisms governing their expression is important in understanding patient-specific response to drugs and cancer risk factors. In silico prediction algorithm programs were used to screen for microRNAs (miRNAs) as potential regulators of UGT2B enzymes, with miR-216b-5p identified as a potential candidate. Luciferase data suggested the presence of a functional miR-216b-5p binding motif within the 3' untranslated regions of UGTs 2B7, 2B4, and 2B10. Overexpression of miR-216b-5p mimics significantly repressed UGT2B7 (P \< 0.001) and UGT2B10 (P = 0.0018) mRNA levels in HuH-7 cells and UGT2B4 (P \< 0.001) and UGT2B10 (P = 0.018) mRNA in Hep3B cells. UGT2B7 protein levels were repressed in both HuH-7 and Hep3B cells in the presence of increasing miR-216b-5p concentrations, corresponding with significant (P \< 0.001 and P = 0.011, respectively) decreases in glucuronidation activity against the UGT2B7-specific substrate epirubicin. Inhibition of endogenous miR-216b-5p levels significantly increased UGT2B7 mRNA levels in HuH-7 (P = 0.021) and Hep3B (P = 0.0068) cells, and increased epirubicin glucuronidation by 85\% (P = 0.057) and 50\% (P = 0.012) for HuH-7 and Hep3B cells, respectively. UGT2B4 activity against codeine and UGT2B10 activity against nicotine were significantly decreased in both HuH-7 and Hep3B cells (P \< 0.001 and P = 0.0048, and P = 0.017 and P = 0.043, respectively) after overexpression of miR-216b-5p mimic. This is the first evidence that miRNAs regulate UGT 2B7, 2B4, and 2B10 expression, and that miR-216b-5p regulation of UGT2B proteins may be important in regulating the metabolism of UGT2B substrates.}, issn = {0022-3565}, URL = {https://jpet.aspetjournals.org/content/359/1/182}, eprint = {https://jpet.aspetjournals.org/content/359/1/182.full.pdf}, journal = {Journal of Pharmacology and Experimental Therapeutics} }