Effect of miR-146a on c-Myc gene expression in HepG2.2.15 cells / 重庆医学

ABSTRACT

Objective To construct the has-miR 146a eukaryotic overexpression vector pmR 146a and to explore its effect on the expression of c-Myc gene in HepG2.2.15 cells.Methods The has-miR-146a precursor gene fragment pre-has-miR-146a was amplified by PCR,then connected to the pmR-mCherry plasmid vector after double enzyme digestion,the accuracy of recombinant vector was verified by colony PCR,double enzyme digestion and sequencing;then the recombinant vector was transfected into HepG2.2.15 cells as the experimental group,meanwhile the empty vector group (transfecting pmR-mCherry empty plasmid group) and blank group(transfecting reagent lip2000+PBS),then the fluorescent protein expression amount was observed under the fluorescence microscopy at 24,48 h;the expression of has miR-146a was evaluated by qPCR;at 24,48 h after transfection,the expression levels of c-Myc gene mRNA were detected by qPCR,and the c-Myc protein expression level after 48 h was detected by Western blot.Results The colony PCR,double enzyme digestion and sequencing verified that the pre-has-miR-146a gene fragment was inserted into the pmR-mCherry vector;at 24,48 h after transfection in the experimental group and empty vector group,intracellular strong fluorescence was seen by fluorescent microscope,the transfection efficiency was at 50％-60％ contrasting without fluorescence;the has-miR-146a expression level in the experimental group was significantly higher than that in the empty vector group and blank group (P＜0.01);the c-Myc mRNA expression at 24,48 h after tranfection was significantly lower than that in the empty vector group and blank group (P＜0.05);the protein expression amount at 48 h after transfection was lower than that in the empty vector group and blank group (P＜0.01).Conclusion The pmR-146a eukaryotic overexpression vector is successfully constructed,this recombinant vector can express miR-146a stably;miR-146a can down-regulate c-Myc cancer gene expression,which can serve as one of potential targets for treating hepatocellular carcinoma.