微环境CAFs源性外泌体调控非小细胞肺癌EGFR-TKI耐药及其机制

EGFR-TKI is the first-choice drug for advanced non small cell lung cancer (NSCLC) patients with EGFR sensitive mutation, but inevitable drug resistance is the "bottleneck" of clinical application. Tumor cell-derived exosomes have been proved to mediate drug resistance transmission and formation among tumor cells. However, it is still unclear whether tumor stromal cell-derived exosomes can deliver lncRNAs to tumor cells and regulate drug resistance. Our previous study firstly found that LncUCA1 was significantly overexpressed in CAFs, the most important component of microenvironment, as well as in CAFs-derived exosomes. Moreover, treatment of NSCLC cells with CAFs-derived exosomes resulted in increased LncUCA1 level and EGFR-TKI resistance. These results reveal that CAFs-derived exosomes play a a critical regulatory role in EGFR-TKI resistance mediated by transfer of LncUCA1. Based on the above findings, we propose that CAFs-derived exosomes may promote EGFR-TKI resistance in NSCLC via transfer of LncUCA1 to NSCLC cells and direct binding to the related miRNAs, thereby facilitating upregulation of their target protein GPR124 and activation of downstream signaling pathways. The present study will clarify the key role and mechanism of CAFs-derived exosomes as an important intercellular messenger in delivery of LncUCA1 from stroma to tumor to regulate EGFR-TKI resistance in cells, animals and patients specimens. Our study will provide new evidences on overcoming the EGFR-TKI resistance by targeting tumor microenvironment.

EGFR-TKI是EGFR敏感突变的晚期非小细胞肺癌（NSCLC）首选药，但普遍耐药成为临床应用的瓶颈。已知肿瘤细胞外泌体可传递LncRNAs介导耐药传递和形成。但肿瘤基质细胞外泌体能否传递LncRNAs调控耐药尚不清楚。我们前期研究率先发现：微环境最主要基质成分CAFs富含LncUCA1并随外泌体分泌，提取CAFs外泌体作用于NSCLC细胞，可上调后者LncUCA1水平、增加EGFR-TKI耐药，揭示CAFs外泌体能调控EGFR-TKI耐药并与传递LncUCA1有关。据此我们提出假设：CAFs外泌体通过传递LncUCA1，调节NSCLC细胞miRNAs从而上调靶蛋白GPR124并激活下游通路，促进EGFR-TKI耐药。本课题拟从细胞、动物、临床水平多层次阐明CAFs外泌体在基质-肿瘤间传递LncUCA1的重要信使作用及关键调控机制，为靶向肿瘤微环境从而克服EGFR-TKI耐药提供新依据。

EGFR-TKI是EGFR敏感突变的晚期非小细胞肺癌（NSCLC）首选药，但普遍耐药成为临床应用的瓶颈。已知肿瘤细胞外泌体可传递LncRNAs介导耐药传递和形成。但肿瘤基质细胞外泌体能否传递LncRNAs调控耐药尚不清楚。我们前期研究率先发现：微环境最主要基质成分CAFs富含LncUCA1并随外泌体分泌，提取CAFs外泌体作用于NSCLC细胞，可上调后者LncUCA1水平、增加EGFR-TKI耐药，揭示CAFs外泌体能调控EGFR-TKI耐药并与传递LncUCA1有关。但后续研究发现不同浓度的CAFs源性外泌体对NSCLC细胞的吉非替尼药敏性无显著差别。因此们调整思路，通过对CAFs、NFs进行转录组学测序和临床标本及细胞水平等实验研究，首次发现CAFs高表达NRK。CAFs高表达NRK可增加Cofilin蛋白磷酸化的水平，增加F-actin聚合，增强CAFs运动能力，从而诱导肺腺癌细胞侵袭迁移。我们的研究结果为靶向CAFs的肺腺癌治疗提供了一个新的候选靶点NRK，并发现了可能与肺腺癌恶性进展相关的潜在靶点Cx26。

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