肺癌干样细胞APE1外泌体介导NSCLC化疗抵抗的机制研究

Apurinic/apyrimidinic endonuclease 1 (APE1), with dual functions of both DNA damage repair activity and redox activity, plays important roles in chemotherapy resistance of non-small cell lung cancer. In our previous study, we have demonstrated that APE1 protein presented in NSCLC patients serum and exosomes. Interestionly, theses APE1-armed exosomes derived from lung cancer stem-like cells had different molecular weight. Numbers of papers have investigated CSCs and stem-like cancer cells is one of the reasons contribute to the chemotherapeutic resistance. Therefore, we suppose that APE1 armed exosomes derived from lung cancer stem-like cells promote NSCLC chemotherapeutic resistance through the interaction among cancer cells. This study take advantages of proteomics, bioinformatics, observation and function analysis of living cells, vector construction, EMSA, Co-IP, animal models and so on to illustrate the mechanism of APE1 armed exosomes derived from lung cancer derived promote the acquirement of stemness and resistance to chemotherapy of lung cancer cells. We will conduct this study from a novel viewpoint to analyze the interactional functions between cancer stem cells and cancer cells, as well as elucidate the mechanism of the acquirement of cell stemness and chemotherapeutic resistance of NSCLC cells, in order to put forward new perspective and theoretical foundation for boosting chemotherapeutic effects of NSCLC.

脱嘌呤脱嘧啶核酸内切酶（APE1）具有DNA损伤修复和氧化还原双功能，在非小细胞肺癌（NSCLC）化疗抵抗中具有重要作用。前期研究发现并证实NSCLC患者外周血循环中存在APE1蛋白及APE1外泌体，但与肿瘤细胞相比，外泌体中的APE1主要来源于诱导的肺癌干样细胞，且其分子量亦不相同。大量研究均已证实，肿瘤干细胞及肿瘤干样细胞是肿瘤化疗抵抗的根源之一。因此，我们提出肺癌干样细胞APE1外泌体通过肿瘤细胞间通讯具有促进NSCLC化疗抵抗的重要作用。本研究拟采用蛋白组学、生物信息学、活细胞观测分析、载体构建、EMSA、Co-IP、动物模型等技术方案阐明肺癌干样细胞来源的APE1外泌体促进肺癌细胞干性获得及其化疗抵抗的机制，本研究将从新视野剖析肿瘤干样细胞与肿瘤细胞之间相互作用的方式，阐明NSCLC细胞干性获得及其对化疗抵抗的分子机制，为提高NSCLC的化疗疗效提供新的思路和理论基础。

目前，非小细胞肺癌铂类耐药仍然是造成大部分非小细胞肺癌患者疗效差的的主要原因，然而非小细胞肺癌铂类耐药的具体机制尚未完全明了。铂类耐药是由多种因素造成的，其中外泌体可能发挥重要作用。外泌体是细胞分泌的携带生物活性物质的纳米级囊泡，根据前期研究基础，我们提出外泌体可能通过其携带的碱基切除修复关键蛋白APE1或某些microRNA传递耐药性。因此，本研究着眼于NSCLC外泌体APE1，外泌体microRNA，对NSCLC铂类耐药的机制进行探索。首先，我们研究了顺铂处理后，NSCLC细胞外泌体APE1的变化情况，以及这种变化与NSCLC对顺铂敏感性的关系，结果显示外泌体APE1的高表达与顺铂敏感性下降有关。临床资料也表明，血浆外泌体APE1升高的患者，铂类化疗疗效差。接着，我们研究了顺铂刺激下，细胞外泌体microRNA的变化情况，结果发现外泌体miR-1273a是变化最为显著的miRNA，外泌体miR-1273a可以增加NSCLC的铂类敏感性，而下降的miR-1273a与铂类化疗疗效差有关。此外，我们初步发现某些microRNA可能受APE1调控，并与铂类化疗疗效相关。以上结果表明，NSCLC铂类化疗耐药与外泌体APE1、外泌体miR-1273a有关，靶向外泌体的APE1或者miR-1273a可作为提高NSCLC铂类化疗敏感性干预手段。