The interplay of oncogenic signaling,oxidative stress and ferroptosis in cancer

Oncogene-induced hyper-proliferation in cancer cells is accompanied by the onset of different stresses, including DNA-replication stress, metabolic stress and oxidative stress. Excessive accumulation of reactive oxygen species (ROS) plays a pivotal and contradictory role in tumor progression. ROS dictates a multitude of cell signaling pathways to facilitate the malignant transformation of tumor cells. In the meantime, oxidative burden in tumor cells mandates reinforcing antioxidant capacity to mitigate detrimental damages. The addiction to oxidative stress and increased iron demands in cancer cells also impinges on the sensitivity of ferroptosis. Targeting redox homeostasis and ferroptosis to overcome drug resistance in cancer treatment has become an attractive research topic. However, the roles of oncogenic signaling in redox regulation and ferroptosis have not been comprehensively discussed. In this review, we summarize current knowledge regarding the interplay between redox regulation and ferroptosis in the context of cancer biology. We emphasize the implication of oncogenic signaling in redox homeostasis and ferroptosis regulation. We also provide an overview of strategies targeting oxidative stress and ferroptosis in cancer treatment.     

过表达miR-199-3p/5p诱导胰腺癌细胞BxPC-3、Panc-1铁死亡的作用机制

目的探讨过表达miR-199-3p/5p诱导胰腺癌细胞BxPC-3和Panc-1铁死亡的作用机制。 方法瞬时转染miR-199-3p/5p模拟物和抑制物至BxPC-3、Panc-1细胞中。qRT-PCR检测细胞中miR-199-3p/5p表达水平；Western blotting检测SCL7A11、BTRC、TFRC蛋白水平。谷胱甘肽(GSH)、Fe2＋、脂质过氧化物(LPO)试剂盒检测细胞GSH、Fe2＋、LPO水平。免疫共沉淀检测BTRC、TFRC泛素化水平。双荧光素酶报告实验检测miR-199与靶基因的相互作用。 结果转染miR-199-3p/5p模拟物后,胰腺癌BxPC-3、Panc-1细胞株中miR-199-3p/5p、TFRC蛋白水平显著上调；SLC7A11、BTRC蛋白水平显著降低；LPO、Fe2＋含量升高,GSH含量降低。过表达BTRC能够显著降低TFRC蛋白水平。miR-199-3p靶向结合SLC7A11,miR-199-5p靶向结合BTRC。 结论过表达miR-199-3p/5p诱导胰腺癌细胞BxPC-3和PANC-1铁死亡,可能与靶向抑制BTRC、SLC7A11促进LPO累积有关。     

基于代谢组学的柠檬烯抗非小细胞肺癌作用机制研究

目的 采用非靶向代谢组学等方法，探究柠檬烯抑制非小细胞肺癌增殖的作用机制。方法 以肺癌A549细胞为研究对象，通过CCK-8法测定柠檬烯抑制A549细胞活力及IC₅₀；通过集落形成、流式细胞检测、铁含量测定及线粒体染色等实验，分别评价柠檬烯的体外抗肺癌及诱导铁死亡作用；代谢组学分析发现柠檬烯的潜在作用通路；最后采用Western blotting对相关通路主要蛋白进行验证。结果 与对照组相比，柠檬烯给药组可以显著抑制A549细胞的增殖及集落的形成，且呈剂量依赖性；光学显微镜观察发现，柠檬烯给药后A549细胞出现脱落现象，并可显著改变其形态；同时柠檬烯具有诱导A549细胞凋亡作用，并阻滞在G₀-G₁期；共聚焦显微镜发现柠檬烯作用后，A549细胞线粒体荧光减弱，同时细胞内铁含量亦显著增加，呈现典型的铁死亡表现；代谢组学研究发现谷胱甘肽(glutathione，GSH)代谢、精氨酸生物合成、D-谷氨酰胺和D-谷氨酸代谢及半胱氨酸和蛋氨酸代谢等多条差异代谢通路，这些通路与细胞内GSH合成密切相关；Western blotting实验发现，柠檬烯给药后细胞中SLC40A1、SLC7A11(xCT)及GPX4蛋白含量显著减少。结论 柠檬烯抗肺癌作用机制可能与降低肺癌细胞中GSH合成及增加Fe²⁺含量诱导其铁死亡有关。     

活性氧与铁死亡通路相互作用在丙酮醛引起的小鼠胚胎成骨细胞损伤中起重要作用

目的 探讨活性氧和铁死亡在丙酮醛诱导小鼠胚胎成骨细胞（MC3T3-E1）损伤中是否存在相互作用。方法 应用丙酮醛损伤MC3T3-E1细胞建立模拟糖尿病骨质损伤的细胞模型。应用细胞计数试剂盒-8（CCK-8）测定MC3T3-E1细胞的存活率;罗丹明123染色荧光显微镜照相法测定线粒体膜电位;双氯荧光素（DCFH-DA）荧光显微镜照相法检测胞内活性氧水平;碱性磷酸酶试剂盒检测定碱性磷酸酶活性;茜素红染色观察成骨细胞晚期标志物-矿化结节的形成;铁离子试剂盒检测铁离子水平;Western blot检测成骨细胞的抑制铁死亡的标志蛋白谷胱甘肽过氧化物酶4（GPX4）的表达水平。结果 0.6 mmol/L 丙酮醛处理MC3T3-E1细胞24 h可明显减少GPX4的表达（P<0.001）,同时可使胞内铁离子浓度升高,细胞存活率降低,线粒体膜电位丢失,胞内活性氧水平升高,碱性磷酸酶活性降低和矿化结节减少（P<0.001）。应用2 mmol/L 活性氧清除剂N-乙酰半胱氨酸和丙酮醛共处理MC3T3-E1细胞24 h可增加GPX4的表达（P<0.01）,应用4 μmol/L铁死亡抑制剂铁抑素-1与丙酮醛共处理成骨细胞24 h可使胞内活性氧水平降低（P<0.001）;应用N-乙酰半胱氨酸或铁抑素-1与丙酮醛共处理成骨细胞24 h均能对抗丙酮醛引起的上述其他细胞损伤（P<0.001）。结论 活性氧与铁死亡通路相互作用在丙酮醛引起MC3T3-E1成骨细胞损伤中起重要的作用。     

脑泰方调控细胞铁转运抑制铁死亡保护脑卒中缺血损伤的机制研究

目的 探讨脑泰方是否通过调控热休克转录因子1（heat shock factor 1,HSF1）/热休克蛋白B1（heat shock proteins B1,HSPB1）通路降低脑铁沉积、抑制活性氧沉积及脂质过氧化产物产生、减轻神经元铁死亡,从而发挥脑卒中缺血损伤保护作用。方法 SD大鼠随机分为假手术组、模型组、脑泰方（27 g/kg）组和去铁酮（125 mg/kg）组,给予药物干预。通过大脑中动脉闭塞（middle cerebral artery occlusion,MCAO）法制备脑缺血大鼠模型,术后2 h进行神经功能评分及取材。TTC染色法检测脑梗死体积;苏木素-伊红（HE）染色观察脑组织形态结构及损伤情况;尼氏染色观察脑组织尼氏体数目;普鲁士蓝染色观察脑组织神经元内铁聚集水平;免疫组化及Western blotting法检测脑组织HSF1、HSPB1、转铁蛋白受体1（transferrin receptor 1,TFR1）和铁蛋白重链多肽（ferritin heavy polypeptide1,FTH1）蛋白表达;铁离子检测试剂盒与丙二醛检测试剂盒及活性氧检测试剂盒检测脑组织铁、丙二醛及活性氧含量。结果 与模型组比较,脑泰方组大鼠脑梗死体积减少,神经功能评分降低（P<0.01）;脑缺血区尼氏体增多,细胞损伤程度降低;含铁聚集颗粒细胞的数目减少;脑铁、丙二醛及活性氧含量降低（P<0.05、0.01）;脑组织HSF1、HSPB1及FTH1蛋白表达上调（P<0.05、0.01）,TFR1蛋白表达下调（P<0.05）。结论 脑泰方可能通过上调HSF1/HSPB1通路,抑制TFR1的表达以减少神经元铁的吸收,上调FTH1的表达以增加铁蛋白的铁存储,以此调控铁代谢稳态平衡,进而抑制因过量的铁通过芬顿反应产生的活性氧及随后脂质过氧化产物引起的缺血性脑卒中神经元铁死亡。     

PLA2G6 guards placental trophoblasts against ferroptotic injury

The recently identified ferroptotic cell death is characterized by excessive accumulation of hydroperoxy-arachidonoyl (C20:4)- or adrenoyl (C22:4)- phosphatidylethanolamine (Hp-PE). The selenium-dependent glutathione peroxidase 4 (GPX4) inhibits ferroptosis, converting unstable ferroptotic lipid hydroperoxides to nontoxic lipid alcohols in a tissue-specific manner. While placental oxidative stress and lipotoxicity are hallmarks of placental dysfunction, the possible role of ferroptosis in placental dysfunction is largely unknown. We found that spontaneous preterm birth is associated with ferroptosis and that inhibition of GPX4 causes ferroptotic injury in primary human trophoblasts and during mouse pregnancy. Importantly, we uncovered a role for the phospholipase PLA2G6 (PNPLA9, iPLA2beta), known to metabolize Hp-PE to lyso-PE and oxidized fatty acid, in mitigating ferroptosis induced by GPX4 inhibition in vitro or by hypoxia/reoxygenation injury in vivo. Together, we identified ferroptosis signaling in the human and mouse placenta, established a role for PLA2G6 in attenuating trophoblastic ferroptosis, and provided mechanistic insights into the ill-defined placental lipotoxicity that may inspire PLA2G6-targeted therapeutic strategies.

Unrestricted lipid peroxidation jeopardizes membrane structure, fluidity, and permeability, and may lead to cell injury or death (1, 2). This injury can be mitigated by antioxidant enzymes, including superoxide dismutase, catalase, thioredoxin, peroxiredoxin, and glutathione peroxidase (GPX) (3). Distinctively, ferroptosis is a recently identified form of lipoxygenase (LOX)-regulated, nonapoptotic cell death, characterized by iron-dependent accumulation of oxygenated phospholipids and relative insufficiency of glutathione peroxidase 4 (GPX4) (4–7). Considering hydroperoxide phospholipids, ferroptosis is characterized by the accumulation of hydroperoxide phosphatidylethanolamines (Hp-PEs) with preference to the fatty acyls arachidonoyl (termed HpETE-PE) and adrenoyl (termed HpDTE-PE) (4). Advanced liquid chromatography–mass spectrometry (LC-MS)-based redox phospholipidomics demonstrated that oxidation by 15-lipoxygenase (15-LOX), when coupled by PE-binding protein 1 (PEBP1), generates the proferroptotic 15-HpETE-PE and 17-HpDTE-PE (4, 8–10). Recently, FSP1 was identified as a vital element of a nonmitochondrial CoQ antioxidant system that acts in parallel to the canonical glutathione-based GPX4 pathway (11, 12).The placenta forms the maternal–fetal interface and plays a vital role in gas, nutrients, and waste exchange, the production of pregnancy hormones, and immune and mechanical defense of the developing fetus (13). These crucial functions are mediated primarily by trophoblasts that cover the entire villous surface of the placenta (14). Importantly, circumstances that have been previously implicated in ferroptosis are associated with placental physiology and pathobiology: 1) akin to processes that define ferroptosis in acute renal failure, asthma, neurotoxicity, cancer, and brain ischemia–reperfusion injury (7, 10, 15–17), the placenta is subject to hypoxia/reperfusion during the normal establishment of placental blood flow and the transition from histotrophic to hemotrophic placental support (18, 19) and later in pregnancy, during uterine contractions before or during labor (20, 21); 2) hypoxia/reperfusion injury has been implicated in the pathogenesis of placental dysfunction underlying preeclampsia, preterm birth, and fetal growth restriction (15, 22, 23); 3) iron, which is required for lipid peroxidation (24), is abundant in placental trophoblasts (25); 4) cellular lipid peroxidation has been described in placental injury (16, 26); and 5) GPX4 mutations or lower GPX4 levels have been associated with human placental dysfunction and preeclampsia (24, 27–29) and inhibitors of ferroptosis-attenuated preeclampsia like symptoms in a rat model (29). These observations underscore the need to further investigate trophoblast ferroptosis and its role in placental injury underlying obstetrical syndromes. Notably, when compared to preeclampsia and fetal growth restriction (FGR), the placental pathobiological pathways causing spontaneous preterm birth (SPTB) and placental injury are less clear. Yet, uterine contractions, the hallmark of SPTB, are associated with placental hypoxia/reoxygenation (H/R), a risk factor for ferroptosis. An increased level of lipid mediators and relevant enzymes, such as PTGS2 (COX2), are associated with ferroptosis (30) and have been implicated in the production of bioactive lipids that stimulate uterine contractions (31).The phospholipase A2 (PLA2) protein family is a group of lipid-modifying enzymes. Within this family, the Ca-independent PLA2 protein, PLA2G6 (PNPLA9, iPLA2beta), is expressed in the human placenta (32). PLA2G6 hydrolyzes the second carbon chain of membrane phospholipids (33), a pivotal step in prostaglandin production (34, 35). Importantly PLA2G6 also hydrolyzes Hp-PE species that are implicated in ferroptosis (36–39). Mutations in PLA2G6 have been associated with Parkinson’s disease, neurodegenerative disorders, and iron accumulation in the brain (34), reviewed in ref. 40. We therefore hypothesized that PLA2G6 activity mitigates ferroptosis, paralleling the GPX4-mediated defense mechanism. Here we demonstrate that: 1) SPTB in humans that is associated with injured placentas exhibits increased levels of Hp-PE, consistent with placental ferroptosis; 2) genetic and pharmacologic inhibition of GPX4 induces ferroptosis in human placental trophoblasts; 3) sublethal activation of ferroptosis signaling leads to cellular trophoblast dysfunction; 4) PLA2G6-deficient trophoblasts exhibit enhanced sensitivity to ferroptosis; and 5) Pl2g6 deficiency sensitizes the mouse pregnancy to placental ferroptosis, accompanied by a higher risk of fetal demise.     

骨科相关疾病发生发展中的铁超载北大核心

背景:铁是人体必需的金属,它的储存和运输机制复杂,且铁代谢平衡受多种因素的调节。当平衡被破坏时,机体发生铁超载会产生大量活性氧和细胞毒性,甚至引发细胞发生铁死亡进而导致组织器官的功能障碍。但目前关于铁超载的研究主要集中在心血管、神经系统和肿瘤疾病方面,而对于其导致的骨稳态平衡失调以及在骨相关疾病中的机制研究仍然有限。目的:重点针对近年来铁超载在相关骨科疾病中的研究展开综述,并通过回顾铁超载在骨科疾病中的最新研究,为骨科相关疾病的治疗策略提供新思路。方法:通过中文检索词“铁,铁超载,铁死亡,骨质疏松,骨关节炎,骨肿瘤,骨相关疾病”以及英文检索词“iron,iron overload,ferroptosis,osteoporosis,osteoarthritis,osteosarcoma,bone related diseases”在中国知网、万方数据库、PubMed、Web of Science等平台进行检索,检索1978年1月至2022年1月的相关文献,共检索到文献1085篇,根据入组标准,最终纳入文献79篇。结果与结论:①铁超载引起的铁死亡在治疗骨科疾病中具有巨大潜力,但存在缺乏临床应用数据、未进入临床试验环节等问题;②铁超载引起铁死亡的研究集中于与铁结合产生活性氧的酶以及铁本身直接参与Fenton反应介导活性氧积累;铁死亡作为一种独立的细胞死亡方式,为治疗这些疾病提供了一种新的方法,以及联合应用现有治疗方案的可能性,并有助于解决某些疾病的耐药性问题;③铁超载通过抑制成骨细胞活性和功能、促进破骨细胞分化和活化来参与骨质疏松症发展过程;铁超载可加速骨关节炎进展并促进软骨细胞凋亡及基质降解;铁超载能够诱导骨肉瘤细胞的铁死亡、凋亡和自噬,并抑制其侵袭能力;④铁超载引起铁死亡相关机制的研究为骨质疏松症、骨关节炎、骨肉瘤等骨科相关疾病治疗提供了新的靶点与方向。     

铁死亡对器官纤维化的影响及中药干预进展

纤维化是指组织损伤后修复反应失调,以器官内纤维结缔组织增多和实质细胞减少为主要特征,进行性纤维化可导致组织结构破坏,造成器官功能衰竭。铁死亡是一种新型的程序性细胞死亡方式,由铁依赖性脂质过氧化物累积引起,受铁代谢、铁自噬、氨基酸代谢和脂质代谢等多种途径调节。铁死亡在纤维化病理进程中起着重要作用,参与器官实质细胞损伤、巨噬细胞炎症、氧化应激和肌成纤维细胞转化等多个病理过程。在纤维化级联反应中,肌成纤维细胞在细胞外基质沉积过程中会发生铁死亡,且通过靶向调节铁死亡可有效减轻慢性器官损伤和组织纤维化。现已证实,多种中药及其有效成分可调控器官实质细胞铁死亡发挥抗纤维化作用,显示出良好的研究前景。该文对铁死亡在肝、肺、肾和心脏纤维化病理进程中的作用及相关中药干预进行总结,以期为中药防治纤维化疾病提供新靶点。     

中医药干预铁死亡机制的研究进展

铁死亡是近年来发现的一种全新的细胞死亡方式,与正常细胞凋亡和坏死不同,铁死亡具有铁离子的依赖性。铁死亡的发生与细胞内脂质活性氧(reactive oxygen species,ROS)的平衡失调息息相关,其通过介导脂质过氧化(lipid peroxidation,LPO),调节谷胱甘肽(glutathione,GSH)和谷胱甘肽过氧化物酶4(glutathione peroxidase 4,GPX4),依赖细胞内铁、ROS和氧化还原稳态失衡,根据Fe-ROS或者GSH-GPX4-ROS信号通路介导细胞死亡。中药具有多靶点、多通路的优势,干预铁死亡具有一定的疗效和价值,本文总结了铁死亡的相关机制,汇总了近年来中医药领域通过GSH-GPX4-ROS通路介导铁死亡的实验研究成果,以期为疾病铁死亡的靶点治疗提供参考。