Introduction: Acquired cancer therapy resistance evolves under selection pressure of immune surveillance and favors mechanisms that promote drug resistance through cell survival and immune evasion. AXL receptor tyrosine kinase is a mediator of cancer cell phenotypic plasticity and suppression of tumor immunity, and AXL expression is associated with drug resistance and diminished long-term survival in a wide range of malignancies, including NSCLC. Methods: We aimed to investigate the mechanisms underlying AXL-mediated acquired resistance to first- and third-generation small molecule EGFR tyrosine kinase inhibitors (EGFRi) in NSCLC. Results: We found that EGFRi resistance was mediated by up-regulation of AXL, and targeting AXL reduced reactivation of the MAPK pathway and blocked onset of acquired resistance to long-term EGFRi treatment in vivo. AXL-expressing EGFRi-resistant cells revealed phenotypic and cell signaling heterogeneity incompatible with a simple bypass signaling mechanism, and were characterized by an increased autophagic flux. AXL kinase inhibition by the small molecule inhibitor bemcentinib or siRNA mediated AXL gene silencing was reported to inhibit the autophagic flux in vitro, bemcentinib treatment blocked clonogenicity and induced immunogenic cell death in drug-resistant NSCLC in vitro, and abrogated the transcription of autophagy-associated genes in vivo. Furthermore, we found a positive correlation between AXL expression and autophagy-associated gene signatures in a large cohort of human NSCLC (n = 1018). Conclusion: Our results indicate that AXL signaling supports a drug-resistant persister cell phenotype through a novel autophagy-dependent mechanism and reveals a unique immunogenic effect of AXL inhibition on drug-resistant NSCLC cells.

中文翻译：

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AXL 靶向消除自噬流并诱导耐药癌细胞中的免疫原性细胞死亡

简介：获得性癌症治疗耐药性在免疫监视的选择压力下演变，并有利于通过细胞存活和免疫逃避促进耐药性的机制。AXL 受体酪氨酸激酶是癌细胞表型可塑性和抑制肿瘤免疫的介质，AXL 表达与耐药性和包括 NSCLC 在内的多种恶性肿瘤的长期存活率降低有关。方法：我们旨在研究 AXL 介导的 NSCLC 中第一代和第三代小分子 EGFR 酪氨酸激酶抑制剂 (EGFRi) 获得性耐药的机制。结果：我们发现 EGFRi 耐药是由 AXL 的上调介导的，靶向 AXL 减少了 MAPK 通路的再激活，并阻止了体内长期 EGFRi 治疗获得性耐药的发生。表达 AXL 的 EGFRi 抗性细胞显示出与简单的旁路信号机制不相容的表型和细胞信号异质性，其特征是自噬通量增加。据报道，小分子抑制剂 bemcentinib 或 siRNA 介导的 AXL 基因沉默抑制 AXL 激酶可抑制体外自噬通量，bemcentinib 治疗在体外阻断耐药性 NSCLC 的克隆形成和诱导免疫原性细胞死亡，并消除自噬相关的转录体内基因。此外，我们在一大群人 NSCLC（n = 1018）中发现 AXL 表达与自噬相关基因特征之间呈正相关。结论：