食管鳞状细胞癌（ESCC）患者全球五年总生存率不足20％，亟需新的治疗策略。云南白草碱是一种自然的β-咖啡碱类生物活性物质，在癌症研究中引起了极大兴趣。本研究旨在研究云南白草碱对ESCC的影响及其机制。我们研究了云南白草碱对ESCC细胞增殖、细胞周期、凋亡和体内肿瘤生长的影响。RNA测序（RNA-seq）、实时PCR和西方印迹法用于检测机制。云南白草碱抑制了体外ESCC细胞生长和体内肿瘤生长。云南白草碱处理的ESCC细胞中差异表达的基因主要涉及内质网蛋白质处理。实时PCR和西方印迹法证实云南白草碱诱导了细胞内内质网应激。使用CRISPR-Cas9基因编辑技术敲除C/EBP同源蛋白（CHOP）消除云南白草碱诱导的死亡受体5和凋亡表达。云南白草碱还诱导CHOP介导的蛋白素-2的表达，进而通过抑制AMP激活蛋白激酶-蛋白激酶B-哺乳动物雷帕霉素靶标信号通路促进自噬体形成。总之，我们的研究结果表明云南白草碱通过调控内质网应激抑制ESCC的生长，提示该物质是ESCC治疗的有前途的候选药物。© 2023 John Wiley & Sons Ltd.

The worldwide overall 5-year survival rate of esophageal squamous cell carcinoma (ESCC) patients is less than 20%, and novel therapeutic strategies for these patients are urgently needed. Harmine is a natural β-carboline alkaloid, which received great interest in cancer research because of its biological and anti-tumor activities. The aim of this study is to examine the effects of harmine on ESCC and its mechanism. We investigated the effects of harmine on proliferation, cell cycle, apoptosis, and tumor growth in vivo. RNA sequencing (RNA-seq), real-time PCR, and western blotting were used to detect the mechanism. Harmine inhibited ESCC cell growth in vitro and tumor growth in vivo. Differentially expressed genes in harmine-treated ESCC cells were mainly involved in protein processing in the endoplasmic reticulum (ER). Real-time PCR and western blotting confirmed harmine-induced cellular ER stress. CRISPR-Cas9 knockout of C/EBP homologous protein (CHOP) abolished harmine-induced expression of death receptor 5 and apoptosis. Harmine also induced the expression of CHOP-mediated sestrin-2, which in turn contributes to autophagosome formation via suppressing the AMP-activated protein kinase-protein kinase B-mammalian target of rapamycin signaling pathway. In conclusion, our results demonstrate that harmine inhibits the growth of ESCC through its regulation of ER stress, suggesting that it is a promising candidate for ESCC treatment.© 2023 John Wiley & Sons Ltd.