lncRNA HNF1α-AS1和PXR正反馈环路调控ABCB1介导紫杉醇抗NSCLC的研究

ABCB1过表达是引起非小细胞肺癌（NSCLC）对紫杉醇敏感性下降的主要原因。我们此前发现PXR可介导ABCB1下调进而增强紫杉醇抗NSCLC作用。近期研究发现干扰lncRNA HNF1α-AS1可下调PXR的表达；而PXR缺失也可降低HNF1α-AS1的表达，据此，我们推测存在调控ABCB1的正反馈环路HNF1α-AS1/PXR，且干预该环路可影响紫杉醇的抗NSCLC作用。本项目拟在体外明确HNF1α-AS1与PXR调控环路及其对ABCB1表达的影响，探究该环路对紫杉醇抗NSCLC药效的影响，并采用基因敲除小鼠考察HNF1α-AS1对紫杉醇药动学的影响，最后在裸鼠抑瘤模型中确证HNF1α-AS1/PXR环路对紫杉醇抗NSCLC的作用，最终阐明HNF1α-AS1与PXR正反馈环路调控ABCB1介导紫杉醇抗NSCLC的作用及机制，为提高NSCLC化疗成功率及新靶点的发现提供新思路和新策略。

Over-expression of ABCB1 gene is the major factor leading to the decreased sensitivity of non-small cell lung cancer (NSCLC) cells to paclitaxel. The results in our preliminary study demonstrated that PXR could down-regulate ABCB1 gene expression and then enhance the anti-NSCLC effect of paclitaxel. Recent studies have found that silencing lncRNAs HNF1α-AS1 can down-regulate the expression of PXR. In addition, there are reports suggesting that the PXR deletion can also decreased the expression of HNF1α-AS1. Therefore, we speculate that there is a positive feedback loop regulating ABCB1 between HNF1α-AS1 and PXR, and intervention of this loop can affect the anti-NSCLC effect of paclitaxel. Firstly, the regulatory loop between HNF1α-AS1 and PXR and their effects on ABCB1 expression will be verified by siRNA interference and over-expression plasmid transfection experiments in A549 cells. Secondly, the effects of HNF1α-AS1 and PXR loss and gain of function on paclitaxel against NSCLC were investigated by cell viability assay and flow cytometry analysis. After that, we will conduct a pharmacokinetic study in HNF1α-AS1 knockout mice to confirm the effects of HNF1α-AS1 on the ABCB1 expression and pharmacokinetics of paclitaxel. Finally, the tumor xenograft experiment will be recruited to elucidate the effect of HNF1α-AS1/PXR positive feedback loop on the anti-NSCLC effect of paclitaxel. This project will provide the novel strategy for improving the chemotherapy success rate and revealing new targets in drug discovery of NSCLC.