目的 探讨大肠癌中miR-145-5p和多药耐药基因(MDR1)蛋白P-糖蛋白（P-gp）的表达及两者的关系。 方法 分别在组织、细胞水平采用SP法、Real-time PCR法、Western blotting法检测50例大肠癌 (CRC)患者组织及30例癌旁正常组织患者中P-gp的表达，miR-145-5p的表达变化对MDR1 mRNA及P-gp的影响及两者与临床病理特征之间的相关性。  结果 大肠癌组织中miR-145-5p表达量明显低于癌旁正常组织，MDR1 mRNA及P-gp的表达量明显高于癌旁正常组织(r=-0.403，P<0.01)。大肠癌细胞(HCT-15)中miR-145-5p 能够抑制MDR1 mRNA及P-gp的表达(P<0.05)。  结论 MiR-145-5p对大肠癌多药耐药基因及蛋白的表达具有调控作用，参与了大肠癌的发生、发展及多药耐药。

Objective To investigate the expression and relationship between miR-145-5p and multidrug resistance gene (MDR1) protein P-glycoprotein(P-gp) in colorectal cancer.  Methods SP, Real-time PCR and Western blotting were used to detect the expression of P-gp colorectal carcinoma (CRC) in 50 patients and in 30 paracancerous normal tissue patients, the effect of miR-145-5p expression on MDR1 mRNA and P-gp and the correlation between them and clinicopathological features.   Results The expression level of miR-145-5p in CRC was significantly lower than that in paracancerous normal tissue, and the expression level of MDR1 mRNA and P-gp was significantly higher than that in paracancerous normal tissue (r=-0.403, P<0.01).MiR-145-5p could inhibit the expression of MDR1 mRNA and P-gp in HCT-15 cells(P<0.05).   Conclusion MiR-145-5p plays a regulatory role in the expression of multidrug resistance genes and proteins in colorectal cancer, and is involved in the occurrence, development and multidrug resistance of colorectal cancer.