曲妥珠单抗（TRA）在人表皮生长因子受体2（HER2）阳性胃癌（GC）患者中显示出显著的疗效。虽然TRA可以帮助治疗HER2阳性乳腺癌，但TRA耐药是一个关键的临床挑战。据报道，巢蛋白在肺癌中调节细胞氧化还原平衡。本研究旨在鉴定巢蛋白对HER2阳性GC细胞对TRA敏感性的功能。通过实时聚合酶链反应（PCR）和Western blotting（WB），分别探讨了巢蛋白和Keap1-Nrf2途径的mRNA和蛋白表达谱之间的关联。通过Cell Counting Kit-8（CCK-8）试验、克隆形成试验、反应性氧化物（ROS）检测和流式细胞术，研究了巢蛋白过表达对GC细胞对TRA的体外敏感性的影响。TRA治疗导致HER2阳性GC细胞株（MKN45和NCI-N87）中巢蛋白下调。巢蛋白过表达降低了GC细胞对TRA的敏感性。巢蛋白过表达增加了Nrf2的表达和活性，以及相关下游抗氧化基因。巢蛋白过表达也显著抑制了TRA诱导的细胞凋亡和ROS产生。基于雌性BALB/c裸鼠的体内肿瘤生长实验表明，巢蛋白上调恢复了被TRA治疗抑制的肿瘤生长速率。总之，本研究证实了巢蛋白对细胞对TRA敏感性的抑制作用。这些结果暗示抗氧化剂巢蛋白-Nrf2轴可能在GC细胞对TRA耐药机制中发挥作用。《胃肠肿瘤学杂志》2023年，版权所有。

Trastuzumab (TRA) shows significant efficacy in patients with human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC). While TRA can help treat HER2-positive breast cancer, TRA resistance is a key clinical challenge. Nestin reportedly regulates the cellular redox homeostasis in lung cancer. This study aimed at identifying the functions of Nestin on the TRA sensitivity of HER2-positive GC cells.Real-time polymerase chain reaction (PCR) and Western blotting (WB) were performed to explore the association between the mRNA and protein expression profiles, respectively, of Nestin and the Keap1-Nrf2 pathway. The influence of Nestin overexpression on the in vitro sensitivity of GC cells to TRA was explored by Cell Counting Kit-8 (CCK-8) assay, colony formation assay, reactive oxygen species (ROS) detection, and flow cytometry.TRA treatment caused Nestin downregulation in two HER2-positive GC cell lines (MKN45 and NCI-N87). Nestin overexpression reduced the sensitivity of GC cells to TRA. The expression and activity of Nrf2 and relevant downstream antioxidant genes were increased by Nestin overexpression. Nestin overexpression also significantly suppressed TRA-induced apoptosis and ROS generation. In vivo tumor growth experiment with female BALB/c nude mice indicated that Nestin upregulation restored the tumor growth rate which was inhibited by TRA treatment.Collectively, the inhibitory effect of Nestin on the TRA sensitivity of cells to TRA was confirmed in this study. These results imply that the antioxidant Nestin-Nrf2 axis may play a role in the mechanism underlying the resistance of GC cells to TRA.2023 Journal of Gastrointestinal Oncology. All rights reserved.