Rationale: Loss of iron-sulfur cluster function predisposes cancer cells to ferroptosis by upregulating iron-starvation response, but the role of glutaredoxin 5 (GLRX5) silencing in ferroptosis remains unknown. We examined the role of GLRX5 functional loss in promoting ferroptosis in cisplatin-resistant head and neck cancer (HNC) cells./nMethods: The effects of sulfasalazine treatment and GLRX5 gene silencing were tested on HNC cell lines and mouse tumor xenograft models. These effects were analyzed concerning cell viability and death, lipid reactive oxygen species (ROS) and mitochondrial iron production, labile iron pool, mRNA/protein expression, and malondialdehyde assays./nResults: Cyst(e)ine deprivation, erastin, or sulfasalazine induced ferroptosis in HNC cells, which was relatively less sensitive in cisplatin-resistant HNC cells. Sulfasalazine or cyst(e)ine deprivation-induced ferroptosis resulted from increased lipid peroxidation and intracellular free iron, which were significantly promoted by short-interfering RNA or short hairpin RNA (shRNA) targeting GLRX5 (P<0.05). GLRX5 silencing activated iron-starvation response and boosted up intracellular free iron through the iron-responsive element-binding activity of increased iron regulatory protein (increased transferrin receptor and decreased ferritin). These effects were rescued by resistant GLRX5 cDNA but not by catalytically inactive mutant GLRX5 K101Q. The same results were noted in an in vivo mouse model transplanted with vector or shGLRX5-transduced HNC cells and treated with sulfasalazine./nConclusion: Our data suggest that inhibition of GLRX5 predisposes therapy-resistant HNC cells to ferroptosis.

中文翻译：

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谷胱甘肽5的抑制使顺铂耐药的头颈部癌细胞易患肥大病。

原理：铁-硫簇功能的丧失会通过上调铁饥饿反应使癌细胞易患肥大症，但谷氨酰胺毒素5（GLRX5）沉默在肥大症中的作用仍然未知。我们检查了在顺铂耐药的头部和颈部癌症（HNC）cells./n促进ferroptosis GLRX5功能丧失的作用方法：柳氮磺吡啶治疗和GLRX5基因沉默的效果上HNC细胞系和小鼠肿瘤异种移植模型中测试。分析了这些影响，涉及细胞生存力和死亡，脂质活性氧（ROS）和线粒体铁的产生，不稳定的铁库，mRNA /蛋白质表达以及丙二醛测定。/n结果：胱氨酸（e）剥夺，抑素或柳氮磺吡啶在HNC细胞中引起肥大病，在顺铂耐药的HNC细胞中相对较不敏感。柳氮磺吡啶或胱氨酸（e）缺乏引起的肥大病是由于脂质过氧化和细胞内游离铁增加所致，而针对GLRX5的短干扰RNA或短发夹RNA（shRNA）可以显着促进脂质过氧化和胞内游离铁（P <0.05）。GLRX5沉默激活铁饥饿反应，并通过增加铁调节蛋白（增加转铁蛋白受体和减少铁蛋白）的铁反应性元素结合活性来增强细胞内游离铁。这些作用可通过抗性GLRX5 cDNA挽救，但不能通过催化失活的突变体GLRX5 K101Q挽救。在体内发现了相同的结果小鼠模型移植用载体或shGLRX5转导HNC细胞，并用sulfasalazine./n处理结论：我们的数据表明GLRX5的抑制易患治疗抗性HNC细胞ferroptosis。