miR-1260b与Wnt通路协同调控人肺腺癌化疗耐药表型的分子机制研究

MicroRNAs (miRNAs) have been identified as important posttranscriptional regulators involved in various biological processes, but the association with tumor chemoresistance has not been fully understood. The taxol-resistant A549 cell line (A549/Taxol) was successfully established and preserved in our lab. Based on the cDNA and miRNA microarray data, we demonstrated that downregulation of secreted frizzled-related protein 1 (SFRP1) might contribute to the taxol resistance of human lung adenocarcinoma cells by activating the Wnt signaling pathway in vitro and in vivo, and miR-1260b was significantly up-regulated in A549/Taxol cell line. By the bioinformatics tools, we identified that SFRP1 was a preferred candidate target of miR-1260b due to two complementary binding sites of miR-1260b in the 3’-UTR of SFRP1 and TCF/LEF transcriptional factors might bind to the promoter of miR-1260b. The aim of this study is to investigate the effects of miR-1260b on the chemoresistance of lung adenocarcinoma in vitro and in vivo, and to explore the molecular mechanisms that crosstalk of miR-1260b and the Wnt signaling pathway contributes to the chemoresistance of human lung adenocarcinoma, which would provide a novel strategy for reversing chemoresistance of lung adenocarcinoma in the future.

MicroRNA (miRNA)通过对基因表达的转录后调节参与多种生理和病理活动，但其在肿瘤化疗耐药表型形成中的作用仍不清楚。本实验室前期成功建立耐紫杉醇人肺腺癌细胞模型(A549/Taxol)，进行基因表达芯片和miRNA芯片检测后发现：分泌型卷曲相关蛋白1 (SFRP1)通过拮抗Wnt通路逆转人肺腺癌细胞化疗耐药特性，而miR-1260b表达水平在A549/Taxol细胞中明显上调。生物信息学分析提示SFRP1基因的3’-UTR区域含有2个miR-1260b结合位点，而miR-1260b启动子区域含有2个Wnt通路下游转录因子TCF/LEF结合位点。本课题拟通过细胞和活体动物模型分析miR-1260b与人肺腺癌细胞对不同化疗药敏感性之间的关系，并探讨miR-1260b与Wnt通路之间相互作用协同参与肺腺癌细胞化疗耐药表型形成的分子机制，为临床个体化治疗肺腺癌提供有价值的分子靶点。

本研究探讨了miR-1260b/SFRP1/Wnt通路功能轴参与人肺腺癌细胞化疗耐药表型形成的分子机制。本实验室前期已成功建立耐紫杉醇人肺腺癌细胞模型(A549/Taxol)，进行miRNA芯片检测发现，miR-1260b表达水平在A549/Taxol细胞中显著上调。进一步的功能实验证实：miR-1260b可在体内、外影响肺腺癌细胞对于紫杉类药物的敏感性，同时伴有细胞增殖能力、凋亡水平、细胞周期分布比例及上皮间质转化表型(epithelial-mesenchymal transition，EMT)的显著变化。而生物信息学研究发现：作为Wnt信号通路拮抗剂，分泌型卷曲相关蛋白1 (secreted frizzled-related protein 1，SFRP1)基因mRNA的3’-UTR区域含有2个miR-1260b的结合位点。采用荧光素酶报告基因及免疫印迹等实验证实：miR-1260b通过负性调控SFRP1影响Wnt信号通路活性，从而参与人肺腺癌细胞紫杉类药物化疗耐药表型的形成。在人肺腺癌组织中，我们亦证实miR-1260b表达水平与SFRP1 mRNA表达水平呈负相关。本研究揭示了miR-1260b与人肺腺癌细胞化疗敏感性的关系及其分子机制，为肺腺癌患者的个体化治疗提供了有价值的分子靶点。围绕本课题，目前已发表SCI论文1篇，核心期刊论文3篇。