Claudin18.2 (CLDN18.2) 在消化系统癌症中过度表达，使其成为抗体药物偶联物 (ADC) 的理想药物靶点。尽管许多针对 CLDN18.2 的 ADC 正在进行临床试验，但不确定的潜在机制对扩展这些药物的效用构成了障碍。在我们的研究中，αCLDN18.2-MMAE（一种由抗 CLDN18.2 单克隆抗体和微管蛋白抑制剂 MMAE 组成的 ADC）通过裂解 CLDN18.2 阳性的 caspase-9/PARP 蛋白诱导剂量依赖性细胞凋亡胃癌细胞。值得注意的是，αCLDN18.2-MMAE处理过程中自噬显着激活，其特点是自噬体的积累，自噬标记物LC3从I型转变为II型，以及完全的自噬流。通过自噬抑制剂 LY294002 抑制自噬可显着增强 αCLDN18.2-MMAE 诱导的细胞毒性和 caspase 介导的细胞凋亡，表明自噬在 CLDN18.2 导向的 ADC 处理的胃癌细胞中具有细胞保护作用。与自噬抑制剂联合使用可显着增强 αCLDN18.2-MMAE 的体内抗肿瘤功效。此外，Akt/mTOR 通路失活被证明与 αCLDN18.2-MMAE 处理的胃癌细胞的自噬启动有关。总之，我们的研究强调了对 CLDN18.2 导向的 ADC 机制的突破性研究，重点关注自噬的关键作用，为 CLDN18.2 导向的 ADC 与自噬抑制剂联合治疗胃癌提供了新的见解.© 2024。作者。

Claudin18.2 (CLDN18.2) is overexpressed in cancers of the digestive system, rendering it an ideal drug target for antibody-drug conjugates (ADCs). Despite many CLDN18.2-directed ADCs undergoing clinical trials, the inconclusive underlying mechanisms pose a hurdle to extending the utility of these agents. In our study, αCLDN18.2-MMAE, an ADC composed of an anti-CLDN18.2 monoclonal antibody and the tubulin inhibitor MMAE, induced a dose-dependent apoptosis via the cleavage of caspase-9/PARP proteins in CLDN18.2-positive gastric cancer cells. It was worth noting that autophagy was remarkably activated during the αCLDN18.2-MMAE treatment, which was characterized by the accumulation of autophagosomes, the conversion of autophagy marker LC3 from its form I to II, and the complete autophagic flux. Inhibiting autophagy by autophagy inhibitor LY294002 remarkably enhanced αCLDN18.2-MMAE-induced cytotoxicity and caspase-mediated apoptosis, indicating the cytoprotective role of autophagy in CLDN18.2-directed ADC-treated gastric cancer cells. Combination with an autophagy inhibitor significantly potentiated the in vivo antitumoral efficacy of αCLDN18.2-MMAE. Besides, the Akt/mTOR pathway inactivation was demonstrated to be implicated in the autophagy initiation in αCLDN18.2-MMAE-treated gastric cancer cells. In conclusion, our study highlighted a groundbreaking investigation into the mechanism of the CLDN18.2-directed ADC, focusing on the crucial role of autophagy, providing a novel insight to treat gastric cancer by the combination of CLDN18.2-directed ADC and autophagy inhibitor.© 2024. The Author(s).