Ferroptosis is a new form of regulated cell death driven by iron-dependent lipid peroxidation. Glutaminolysis and tricarboxylic acid cycle are involved in ferroptosis, but the underlying metabolic process remains unclear. We examined the role of dihydrolipoamide dehydrogenase (DLD) in ferroptosis induction in head and neck cancer (HNC). The effects of cystine deprivation or sulfasalazine treatment and of DLD gene silencing/overexpression were tested on HNC cell lines and mouse tumor xenograft models. These effects were analyzed with regard to cell death, lipid reactive oxygen species (ROS) and mitochondrial iron production, mitochondrial membrane potential, mRNA/protein expression, and α-ketoglutarate dehydrogenase (KGDH)/succinate/aconitase activities. Cystine deprivation induced ferroptosis via glutaminolysis. Cystine deprivation or import inhibition using sulfasalazine induced cancer cell death and increased lipid ROS and mitochondrial iron levels, which had been significantly decreased by short-interfering RNA (siRNA) or short hairpin RNA (shRNA) targeting DLD (P < 0.01) but not by dihydrolipoyl succinyltransferase. The same results were noted in an in vivo mouse model transplanted with vector or shDLD-transduced HN9 cells. After cystine deprivation or sulfasalazine treatment, mitochondrial membrane potential, mitochondrial free iron level, KGDH activity, and succinate content significantly increased (P < 0.001), which had been blocked by DLD siRNA or shRNA and were consequently rescued by resistant DLD cDNA. Cystine deprivation caused iron starvation response and mitochondrial iron accumulation for Fenton reaction and ferroptosis. Our data suggest a close association of DLD with cystine deprivation- or import inhibition-induced ferroptosis.

Ferroptosis是受铁依赖性脂质过氧化作用驱动的一种新的调控细胞死亡的形式。谷氨酰胺分解和三羧酸循环参与肥大症，但潜在的代谢过程仍不清楚。我们检查了二氢脂酰胺脱氢酶（DLD）在头颈部癌（HNC）的肥大病诱导中的作用。在HNC细胞系和小鼠肿瘤异种移植模型上测试了胱氨酸剥夺或柳氮磺吡啶治疗和DLD基因沉默/过表达的作用。分析了细胞死亡，脂质活性氧（ROS）和线粒体铁的产生，线粒体膜电位，mRNA /蛋白质表达以及α-酮戊二酸脱氢酶（KGDH）/琥珀酸/花生酸酯酶活性方面的这些影响。胱氨酸剥夺通过谷氨酰胺分解诱导肥大病。P  ＜0.01），但不是通过二氢脂酰琥珀酰转移酶。在移植了载体或shDLD转导的HN9细胞的体内小鼠模型中，注意到了相同的结果。剥夺胱氨酸或柳氮磺胺吡啶处理后，线粒体膜电位，线粒体游离铁水平，KGDH活性和琥珀酸含量显着增加（P  <0.001），这已被DLD siRNA或shRNA阻断，因此被抗性DLD cDNA挽救。胱氨酸剥夺引起铁饥饿反应和线粒体铁积累，引起芬顿反应和肥大症。我们的数据表明DLD与胱氨酸剥夺或进口抑制引起的肥大病密切相关。