The antibiotic antimycin A (AMA) is commonly used as an inhibitor for the electron transport chain but its application in anticancer studies is rare. Recently, the repurposing use of AMA in antiproliferation of several cancer cell types has been reported. However, it is rarely investigated in oral cancer cells. The purpose of this study is to investigate the selective antiproliferation ability of AMA treatment on oral cancer cells. Cell viability, flow cytometry, and western blotting were applied to explore its possible anticancer mechanism in terms of both concentration‐ and exposure time‐effects. AMA shows the higher antiproliferation to two oral cancer CAL 27 and Ca9‐22 cell lines than normal oral HGF‐1 cell lines. Moreover, AMA induces the production of higher reactive oxygen species (ROS) levels and pan‐caspase activation in oral cancer CAL 27 and Ca9‐22 cells than in normal oral HGF‐1 cells, providing the possible mechanism for its selective antiproliferation effect of AMA. In addition to ROS, AMA induces mitochondrial superoxide (MitoSOX) generation and depletes mitochondrial membrane potential (MitoMP). This further supports the AMA‐induced oxidative stress changes in oral cancer CAL 27 and Ca9‐22 cells. AMA also shows high expressions of annexin V in CAL 27 and Ca9‐22 cells and cleaved forms of poly (ADP‐ribose) polymerase (PARP), caspase 9, and caspase 3 in CAL 27 cells, supporting the apoptosis‐inducing ability of AMA. Furthermore, AMA induces DNA damage (γH2AX and 8‐oxo‐2′‐deoxyguanosine [8‐oxodG]) in CAL 27 and Ca9‐22 cells. Notably, the AMA‐induced selective antiproliferation, oxidative stress, and DNA damage were partly prevented from N‐acetylcysteine (NAC) pretreatments. Taken together, AMA selectively kills oral cancer cells in an oxidative stress‐dependent mechanism involving apoptosis and DNA damage.

中文翻译：

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抗霉素 A 通过氧化应激介导的细胞凋亡和 DNA 损伤对口腔癌细胞显示出选择性的抗增殖作用

抗生素抗霉素 A (AMA) 通常用作电子传递链的抑制剂，但其在抗癌研究中的应用很少。最近，已经报道了 AMA 在几种癌细胞类型的抗增殖中的再利用用途。然而，它很少在口腔癌细胞中进行研究。本研究的目的是研究 AMA 治疗对口腔癌细胞的选择性抗增殖能力。应用细胞活力、流式细胞术和蛋白质印迹法探索其在浓度和暴露时间效应方面可能的抗癌机制。AMA 对两种口腔癌 CAL 27 和 Ca9-22 细胞系的抗增殖能力高于正常口腔 HGF-1 细胞系。而且，与正常口腔 HGF-1 细胞相比，AMA 诱导口腔癌 CAL 27 和 Ca9-22 细胞产生更高的活性氧 (ROS) 水平和泛半胱天冬酶活化，为 AMA 的选择性抗增殖作用提供了可能的机制。除 ROS 外，AMA 还诱导线粒体超氧化物 (MitoSOX) 生成并消耗线粒体膜电位 (MitoMP)。这进一步支持了 AMA 诱导的口腔癌 CAL 27 和 Ca9-22 细胞中的氧化应激变化。AMA 还显示 CAL 27 和 Ca9-22 细胞中膜联蛋白 V 的高表达以及 CAL 27 细胞中聚（ADP-核糖）聚合酶 (PARP)、caspase 9 和 caspase 3 的裂解形式，支持 AMA 的凋亡诱导能力. 此外，AMA 在 CAL 27 和 Ca9-22 细胞中诱导 DNA 损伤（γH2AX 和 8-oxo-2'-deoxyguanosine [8-oxodG]）。尤其，N-乙酰半胱氨酸 (NAC) 预处理部分阻止了 AMA 诱导的选择性抗增殖、氧化应激和 DNA 损伤。综上所述，AMA 以一种涉及细胞凋亡和 DNA 损伤的氧化应激依赖性机制选择性杀死口腔癌细胞。