RT Journal Article
SR Electronic
T1 MicroRNAs Regulate CYP3A4 Expression via Direct and Indirect Targeting
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 2112
OP 2117
DO 10.1124/dmd.109.027680
VO 37
IS 10
A1 Pan, Yu-Zhuo
A1 Gao, Wenqing
A1 Yu, Ai-Ming
YR 2009
UL http://dmd.aspetjournals.org/content/37/10/2112.abstract
AB CYP3A4 metabolizes many drugs on the market. Although transcriptional regulation of CYP3A4 is known to be tightly controlled by some nuclear receptors (NR) including vitamin D receptor (VDR/NR1I1), posttranscriptional regulation of CYP3A4 remains elusive. In this study, we show that noncoding microRNAs (miRNAs) may control posttranscriptional and transcriptional regulation of CYP3A4 by directly targeting the 3′-untranslated region (3′UTR) of CYP3A4 and indirectly targeting the 3′UTR of VDR, respectively. Luciferase reporter assays showed that CYP3A4 3′UTR-luciferase activity was significantly decreased in human embryonic kidney 293 cells transfected with plasmid that expressed microRNA-27b (miR-27b) or mouse microRNA-298 (mmu-miR-298), whereas the activity was unchanged in cells transfected with plasmid that expressed microRNA-122a or microRNA-328. Disruption of the corresponding miRNA response element (MRE) within CYP3A4 3′UTR led to a 2- to 3-fold increase in luciferase activity. Immunoblot analyses indicated that CYP3A4 protein was down-regulated over 30% by miR-27b and mmu-miR-298 in LS-180 and PANC1 cells. The decrease in CYP3A4 protein expression was associated with significantly decreased CYP3A4 mRNA levels, as determined by quantitative real-time PCR (qPCR) analyses. Likewise, interactions of miR-27b or mmu-miR-298 with VDR 3′UTR were supported by luciferase reporter assays. The mmu-miR-298 MRE site is well conserved within the 3′UTR of mouse, rat, and human VDR. Down-regulation of VDR by the two miRNAs was supported by immunoblot and qPCR analyses. Furthermore, overexpression of miR-27b or mmu-miR-298 in PANC1 cells led to a lower sensitivity to cyclophosphamide. Together, these findings suggest that CYP3A4 gene expression may be regulated by miRNAs at both the transcriptional and posttranscriptional level. Copyright © 2009 by The American Society for Pharmacology and Experimental Therapeutics