miR-103与胃癌多药耐药作用机制探讨

Molecular mechanism of multidrug resistance in gastric cancer by miR-103

目的既往研究肿瘤耐药均集中在DNA水平,而DNA又影响mRNA及蛋白质表达。但是mRNA与编码蛋白质的表达并不成比例,而非编码RNA恰好能解释两者之间的不平衡。非编码RNA即微小RNA(microRNA,miRNA),是一类内源性短链非编码小分子核糖核苷酸,长度约18~25个核糖核苷酸,是转录后基因表达调节的关键分子,参与胃癌的发生发展。本研究旨在探讨miR-103在胃癌多药耐药中作用及其分子机制。方法miRNA芯片筛选SGC7901/ADR及SGC7901细胞差异表达miRNA,应用qRT-PCR验证miR-103表达;将miR-103的拟似物及抑制物分别转染SGC7901/ADR及SGC7901细胞,MTT法检测转染前后对多柔比星敏感性变化;蛋白质印迹法检测miR-103对caveolin-1表达的影响。结果 miR-103在SGC7901/ADR细胞中表达(0.32±0.04)显著低于SGC7901细胞。miR-103拟似物转染SGC7901/ADR细胞后对多柔比星的敏感性较对照组显著提高,IC_(50)由(18.83±0.32)μg/mL下降到(4.54±0.29)μg/mL,t=1.04,P<0.05;而miR-103抑制物转染SGC7901细胞后对多柔比星的敏感性显著降低,IC_(50)由(1.65±0.03)μg/mL上升到(15.27±0.26)μg/mL,t=1.25,P<0.05。miR-103靶向作用于caveolin-1的3’-UTR,并在转录后水平负向调控caveolin-1表达。结论 miR-103通过靶向负调控caveolin-1表达,增加SGC7901/ADR细胞对多柔比星敏感性,从而逆转胃癌多药耐药。

OBJECTIVE Traditionally,therapeutic targets and modulators are focused at the DNA level,and changes in messenger RNA（mRNA）and protein expression levels.Expression profiling has usually been performed at the mRNA level,but mRNA and encoded protein levels are not necessarily proportional,and the expression of noncoding RNAs has recently been suggested to contribute to the lack of proportionality between mRNA and encoded proteins.MicroRNAs（miRNAs）are small noncoding RNAs of 18-25 nucleotides in length that negatively modulate protein expression.MicroRNAs as post-transcriptional regulator play a key role in a variety of biological behavior of tumor,and are involved in gastric carcinogenesis and development.The objective of this study was to investigate the Molecular mechanism of multidrug resistance in gastric cancer by miR-103.METHODS miRNA expression in SGC7901/ADR and parental SGC7901 cells were measured by microarray profiling.To verify the results obtained,we performed quantitative real-time polymerase chain reaction（RT-PCR）in the two cell lines.miR-103 mimics and inhibitors were transfected into SGC7901/ADR and SGC7901 cells respectively,and adriamycin sensitivity was detected by MTT assay before and after transfection.Western blot was applied to test caveolin-1expression.RESULTS miR-103 was down-regulated in MDR gastric cancer cells.Compared with control group,SGC7901/ADR cells transfected with miR-103 mimics showed greatly enhanced sensitivity to adriamycin,IC50 decreased from（18.83±0.32）μg/mL to（4.54±0.29）μg/mL（t=1.04,P〈0.05）.In contrast,suppression of the miR-103 in the SGC7901 cells resulted in a decreased sensitivity to Adriamycin,IC50 increased from（1.65±0.03）μg/mL to（15.27±0.26）μg/mL（t=1.25,P〈0.05）.CONCLUSION miR-103 effectively increases the sensitivity of gastric cancer cells to adriamycin,and this effect of miR-103 may be due to its regulation of caveolin-1expression.