中文摘要：

目的：探讨miRNA-181a对乳腺癌耐药蛋白（ BCRP）及其介导的乳腺癌细胞耐药性的调控作用。方法应用生物信息学预测 BCRP mRNA-3ˊUTR 与 miR-181a 的结合位点；荧光素酶报告分析检测miR-181a与BCRP mRNA-3ˊUTR的结合作用；qRT-PCR和Western blot检测细胞中相关蛋白表达水平。结果与阴性转染组比较,miR-181a mimic 与PGL3-BCRP 3ˊUTR共转染后,荧光素酶活性明显降低（ P〈0.05）。 miR-181a mimic转染到MCF7/MX细胞48 h后,与阴性转染组相比,导致原本 miR-181a低表达的 MCF-7/MX细胞中miR-181a的表达增加（P〈0.05）,BCRP mRNA和蛋白表达明显下降（P〈0.05）,而MRP、P-gp、LRP的mRNA和蛋白水平均无明显改变（P〉;0.05）；MCF-7细胞在miR-181a inhibitor转染48 h后,与阴性转染组相比,miR-181a的表达降低（ P〈0.05）。同时, BCRP mRNA和蛋白表达明显增加（P〈0.05）。而MRP、P-gp、LRP的mRNA和蛋白水平无明显改变（P〉;0.05）。结论 miR-181a可通过靶向作用于BCRP mRNA-3ˊUTR区,调控BCRP表达。

英文摘要：

Aim ToinvestigatetheeffectsofmiRNA-181 a on breast cancer resistance protein （ BCRP ） . Methods Bioinformaticspredictedbindingsitesof BCRP mRNA-3ˊUTR region and miR-181 a;further lu-ciferase reporter gene analysis confirmed that miR-181 a could combine with BCRP mRNA-3ˊUTR; qRT-PCR and Western blot detected related mRNA and protein expressionlevels.Results Comparedwithnegative transfection group, after the miR-181a mimic and PGL3-BCRP 3ˊUTR were co-transfected, luciferase ac-tivity was significantly decreased （ P 〈0 . 05 ） . After miR-181a mimic transfected MCF7/MX cells for 48h, compared to the negative group, the expression of miR-181 a in MCF-7/MX cells was increased （ P〈0. 05 ） , BCRP mRNA, BCRP protein expression were signifi-cantly decreased （ P〈0 . 05 ） , while mRNA expression and protein levels of MRP, P-gp, LRP did not change significantly （ P 〉;0. 05 ）; after transfecting miR-181 a inhibitor for 48h, compared to the negative group, the expression of miR-181 a in MCF-7 cells was reduced （P〈0. 05）. Meanwhile,BCRP mRNA expression and BCRP protein expression were also significantly in-creased （ P〈0. 05 ） . The mRNA expression and pro-tein levels of MRP, P-gp, LRP did not change signifi-cantly（P〉;0.05）.Conclusion miR-181acanregu-late BCRP expression by targeting the BCRP mRNA-3ˊUTR region.