Zhang Shengqiang, Guo Jida, Zhang Hongyan, Tong Lu, Zhang Linyou
Department of Thoracic Surgery, The 2nd Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang, P. R. China.
Department of Physiology and Neurobiology, Mudanjiang Medical University, Mudanjiang 157000, Heilongjiang, P. R. China.
Recent Pat Anticancer Drug Discov. 2023;18(3):397-407. doi: 10.2174/1574892817666220905114120.
Gliotoxin, a secondary metabolite isolated from marine-derived Aspergillus fumigatus, has demonstrated anti-tumor properties in several cancers. Ferroptosis, a recently discovered type of programmed cell death that depends on the accumulation of iron and lipid peroxides, participates in the occurrence and development of various diseases, including cancer. A recent patent, US20200383943, has suggested that the promotion of ferroptosis is a method of cancer treatment. Therefore, the development of drugs that induce ferroptosis in cancer cells would constitute a novel therapeutic approach.
Gliotoxin is a natural compound which has exhibited anti-tumor properties in multiple cancers, however, studies of the effect of gliotoxin on esophageal cancer are lacking. Although cancer treatment has shown great progress, including traditional surgery, chemotherapy, radiotherapy, and immunotherapy, the prognosis of esophageal cancer is still poor. Therefore, the development of new treatment approaches for esophageal cancer is necessary.
The effects of gliotoxin on esophageal cancer cells were determined by functional assays, such as CCK-8, wound healing and transwell assays. We used online tools to predict the target genes of gliotoxin, followed by further verification using Western blotting assays. To assess the role of gliotxin in inducing ferroptosis in esophageal cancer, we detected characteristics associated with ferroptosis including ROS, MDA, GSH and Fe.
Using online tools SEA and SwissTargetPrediction, we predicted that SUV39H1 was the gliotoxin target gene. Furthermore, in esophageal cancer tissues, SUV39H1 was expressed at higher levels than in normal tissues, while in patients with Esophageal Squamous Cell Carcinoma (ESCC), high expression levels of SUV39H1 indicated a poor prognosis. In vitro, we observed that gliotoxin increased ESCC cell death and inhibited cell migration. We treated ESCC cells with pan-caspase inhibitor Z-VAD-FMK or ferroptosis inhibitors, including Fer-1 and DFO. Our results showed that Fer-1 and DFO reduced the toxic effects of gliotoxin, while Z-VAD-FMK did not. Furthermore, gliotoxin treatment reduced tumor weight and volume in the xenograft tumor mouse model.
In summary, our findings indicate that gliotoxin downregulated SUV39H1 expression in ESCC cells and induced ferroptosis, suggesting a novel natural therapy for ESSC.
Gliotoxin是一种从海洋来源的烟曲霉中分离出的次生代谢产物，已在多种癌症中显示出抗肿瘤特性。铁死亡是一种最近发现的程序性细胞死亡类型，依赖于铁和脂质过氧化物的积累，参与包括癌症在内的各种疾病的发生和发展。最近的一项专利（美国专利号：US20200383943）表明，促进铁死亡是一种癌症治疗方法。因此，开发能诱导癌细胞发生铁死亡的药物将构成一种新的治疗方法。
Gliotoxin是一种在多种癌症中均表现出抗肿瘤特性的天然化合物，然而，关于Gliotoxin对食管癌作用的研究尚缺乏。尽管癌症治疗已取得了巨大进展，包括传统手术治疗、化疗、放疗和免疫治疗，但食管癌的预后仍然很差。因此，开发新的食管癌治疗方法很有必要。
通过CCK-8、伤口愈合和Transwell实验等功能实验来确定Gliotoxin对食管癌细胞的作用。我们使用在线工具预测Gliotoxin的靶基因，随后通过蛋白质免疫印迹实验进一步验证。为了评估Gliotoxin在诱导食管癌铁死亡中的作用，我们检测了与铁死亡相关的特征，包括活性氧（ROS）、丙二醛（MDA）、谷胱甘肽（GSH）和铁。
使用在线工具SEA和SwissTargetPrediction，我们预测SUV39H1是Gliotoxin的靶基因。此外，在食管癌组织中，SUV39H1的表达水平高于正常组织，而在食管鳞状细胞癌（ESCC）患者中，SUV39H1的高表达水平表明预后较差。在体外实验中，我们观察到Gliotoxin增加了ESCC细胞死亡并抑制了细胞迁移。我们用泛半胱天冬酶抑制剂Z-VAD-FMK或铁死亡抑制剂（包括Fer-1和去铁胺-DFO）处理ESCC细胞。我们的结果表明，Fer-1和DFO降低了Gliotoxin的毒性作用，而Z-VAD-FMK则没有。此外，Gliotoxin治疗降低了异种移植肿瘤小鼠模型中的肿瘤重量和体积。
总之，我们的研究结果表明，Gliotoxin下调了ESCC细胞中SUV39H1的表达并诱导了铁死亡，提示了一种针对ESCC的新型天然治疗方法。
