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    Topic review

    Punicic Acid and Ferroptotic Cell

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    Submitted by: Perrine Vermonden

    Definition

    Plant-derived conjugated linolenic acids (CLnA) have been widely studied for their preventive and therapeutic properties against diverse diseases such as cancer. In particular, punicic acid (PunA), a conjugated linolenic acid isomer (C18:3 c9t11c13) present at up to 83% in pomegranate seed oil, has been shown to exert anti-cancer effects, although the mechanism behind its cytotoxicity remains unclear. Ferroptosis, a cell death triggered by an overwhelming accumulation of lipid peroxides, has recently arisen as a potential mechanism underlying CLnA cytotoxicity. In the present study, we show that PunA is highly cytotoxic to HCT-116 colorectal and FaDu hypopharyngeal carcinoma cells grown either in monolayers or as three-dimensional spheroids. Moreover, our data indicate that PunA triggers ferroptosis in carcinoma cells. It induces significant lipid peroxidation and its effects are prevented by the addition of ferroptosis inhibitors. A combination with docosahexaenoic acid (DHA), a known polyunsaturated fatty acid with anticancer properties, synergistically increases PunA cytotoxicity. Our findings highlight the potential of using PunA as a ferroptosis-sensitizing phytochemical for the prevention and treatment of cancer.

    1. Introduction

    For centuries, plant-derived lipids have been used for their therapeutic properties against various diseases [1][2]. Fatty acids are the building blocks of natural lipids and represent a large class of compounds that are diverse in composition. They act as a source of energy as well as structural and functional components of cells [1]. Saturated fatty acids have no double bond while unsaturated fatty acids present at least one double bond in their carbon chain [3]. Polyunsaturated fatty acids (PUFAs) are classified according to the number and position of double bonds in the carbon chain. Most PUFAs present double bonds separated by a methylene (-CH2-) group. In contrast, some PUFAs display double bonds that are not interrupted by a methylene group and are known as conjugated fatty acids [1][4]. Conjugated linoleic acids (CLAs) have two conjugated double bonds while conjugated linolenic acids (CLnAs) have three double bonds of which at least two are conjugated [5]. The three double bonds of plant-derived CLnAs are in a conjugated configuration. In contrast to CLAs that are particularly found in dairy products, CLnAs are mainly contained in diverse plant seed oils, such as pomegranate seed oil rich in punicic acid (PunA, C18:3 c9t11c13) and tung, bitter gourd or ricinodendron seed oil rich in α-eleostearic acid (α-ESA, C18:3 c9t11t13) [6][7][8].
    Among the conjugated fatty acids, CLAs have been the most extensively studied for their beneficial effects on human health. These include anti-obesity, anti-atherogenic, anti-diabetic, anti-carcinogenic and immunomodulatory properties [7][9][10][11][12][13]. However, the interest towards CLnAs has significantly increased over the last two decades, partially due to their high content in some seed oils, suggesting that CLnAs may be more available for preventive or even therapeutic purposes than previously expected [2]. In fact, CLnAs have been shown to possess anti-inflammatory [14][15][16], anti-obesity [14][17][18], anti-diabetic [19][20] and anti-cancer activities [1][2][21][22][23]. Specifically, PunA has been reported to exert a strong anti-cancer activity, both in vitro [7][24][25][26] and in vivo [4][27][28]. PunA anti-cancer activity is thought to be associated with lipid peroxidation [7]. In fact, CLnAs are more susceptible to autoxidation than their non-conjugated counterpart, namely α-linolenic acid (C18:3 c9c12c15), due to the ease of free radical formation by the quick electron delocalization at the level of the conjugated double bonds [29]. However, the exact mechanisms behind PunA cytotoxicity towards cancer cells remain poorly understood.
    Ferroptosis is a form of iron-catalyzed regulated cell death that is morphologically, biochemically and genetically distinct from other regulated cell deaths, such as apoptosis and necroptosis [30][31]. Ferroptotic cell death is characterized by the overwhelming accumulation of lipid hydroperoxides, a form of reactive oxygen species (ROS) generated through oxidation of PUFAs [32][33][34][35]. This mode of cell death is executed through PUFA-containing phospholipid peroxidation as well as the presence of redox-active iron and a defective lipid peroxide repair (i.e., deficiency in glutathione and impairment of glutathione peroxidase 4) [36]. More recently, other key ferroptosis suppressors have been identified, such as the ferroptosis suppressor protein 1, which regenerates the radical trapping-reduced form of ubiquinone and the Ca2+-independent phospholipase A2β, which hydrolyses lipid hydroperoxides from cell membranes [37][38]. Mechanistically, the formation of lipid hydroperoxides requires di-oxygenation of lipid double bonds, which occurs either spontaneously by autoxidation or through enzyme-catalyzed processes controlled by lipoxygenases [39][40][41] and oxidases [42]. Accumulation of lipid hydroperoxides eventually leads to the disruption of cell membranes, production of reactive aldehydes and finally cell death.
    In the last decade, multiple drugs impacting the activity of various enzymes or transporters have been identified as ferroptosis inducers in cancer cells [30][43][44][45]. Another strategy, as yet largely unexplored for the induction of ferroptosis, may lie in the promotion of lipid hydroperoxide production by preferentially introducing high amounts of peroxidable PUFAs in cancer cells. In fact, several lines of research suggest that a wide range of PUFAs might sensitize cancer cells to ferroptosis by causing a dramatic accumulation of phospholipid-derived peroxides [37][46][47][48]. Recently, ferroptosis has appeared as a potential cell death pathway underlying CLnA cytotoxicity [49]. However, more work is  warranted to further dissect the potential pro-ferroptotic effects of PunA. This is even more necessary as PunA, unlike other CLnAs, is a readily available phytochemical. It is indeed present in large amounts in pomegranate seed oil [6], the only CLnA-rich oil widely recognized as edible on the market [14].
     Our data indicate that PunA induces ferroptosis in carcinoma cells by triggering an intense lipid peroxidation, a phenomenon that is prevented by ferroptosis inhibitors. In addition, a combination of PunA with docosahexaenoic acid (DHA, C22:6 c4c7c10c13c16c19), another PUFA recently shown to induce ferroptosis under acidosis [50], increases its effect in a synergistic manner. These findings suggest that PunA, possibly in combination with DHA, could be used as an anti-cancer agent.

    2. Punicic acid as a ferroptosis-sensitizing agent

    In the present work, we show that PunA is cytotoxic for hypopharyngeal (FaDu) and colorectal (HCT-116) carcinoma cells in vitro, either grown in monolayers or as three-dimensional spheroids. At micromolar doses, only PunA was cytotoxic to carcinoma cells, with a dramatic loss of viability in both HCT-116 and FaDu cells, whereas DHA, a known omega-3 PUFA, has no cytotoxic impact and even increased HCT-116 cell viability. We found that the viability of HCT-116 and FaDu carci- noma cells exposed to both DHA at 100 μM and PunA at a sub-lethal dose of 7 μM for 72 h was more greatly reduced than upon treatment with PunA alone. The combination of PunA with DHA also significantly decreased spheroid growth (vs. single fatty acid treatments), suggesting that PunA and DHA act in a supraadditive way to impact on carcinoma cell viability. Next, we evaluated the impact of two ferroptosis inhibitors, namely ferro- statin-1 (fer-1) and α-tocopherol (α-T), on the cytotoxicity of PunA on HCT-116 and FaDu carcinoma cells. PunA cyto- toxicity on HCT-116 and FaDu carcinoma cells was inhibited by the addition of fer-1 and α-T, as well as by the iron chelator deferoxamine mesylate (DFOM). On the contrary, neither the apoptosis inhibitor ZVAD-fmk nor the necroptosis inhibitor necrostatin-1 prevented PunA cytotoxicity on HCT-116 and FaDu carcinoma cells, further supporting ferroptosis as the cell death pathway triggered upon PunA exposure. Both α-T and fer-1 also strongly inhibited the cytotoxicity of PunA on HCT-116 and FaDu spheroids. As ferroptosis execution is characterized by an abundant accumulation of lipid peroxide species, we investigated whether PunA treatment triggers an increase in lipid peroxidation in carcinoma cells. We used the C11-BODIPY assay, which measures the ability of cells to peroxidize the double bonds of this BODIPY probe, as well as the MDA assay, which measures the secondary products resulting from intracellular lipid peroxidation. We showed that PunA triggers lipid peroxidation in carcinoma cells in a manner and a time course that are consistent with the induction of ferroptosis. 

    3. Development and Findings

    Despite great advances in treatment, cancer remains the second cause of mortality worldwide, with the majority of cancer deaths caused by carcinoma [51]. Many anti-cancer drugs aim at triggering apoptosis as a strategy to eliminate cancer cells. However, the effectiveness of these drugs is limited by the tendency of cancer cells to acquire resistance to apoptosis [52]. In this regard, exploiting other types of cell death mechanisms such as ferroptosis opens up new therapeutic avenues. PunA, a CLnA isomer, is cytotoxic to different carcinoma cell lines by triggering intracellular lipid peroxidation and these effects are completely prevented in the presence of ferroptosis inhibitors. Neither apoptosis nor necroptosis inhibitors blocked PunA cytotoxicity, further supporting the ability of PunA to specifically trigger ferroptosis in cancer cells. Ferroptotic effects of PunA were observed from low concentrations, both on carcinoma cells grown as monolayers and on cells organized as three-dimensional spheroids.
    Our results indicate that DHA and PunA may work synergistically to induce cell death in carcinoma cells. To our knowledge, this is the first study suggesting synergies between PUFA and CLnA cytotoxicities on cancer cells and spheroids. Even though in vivo evidence of their synergistic mechanism should be provided, such a combination of PUFAs and CLnAs may be an interesting therapeutic option to increase their respective effects in cancer patients.
    As indicated by our results as well as by other in vitro and in vivo studies [1][49], CLnAs are phytochemicals with promising anti-cancer effects that could be exploited as preventive or even therapeutic agents. CLnAs are mainly found in seed oils of specific plants and the CLnA content can reach up to 80% of the total lipids [5], making CLnAs accessible nutritional phytochemicals. However, CLnA-rich seed oils remain too little known and available on the market to be used on a large scale as anti-cancer agents. Only pomegranate seed oil is currently widely recognized as an edible oil on the market [14], making PunA the most relevant CLnAs to be further investigated as a potential anti-cancer agent. A strategy to make these phytochemicals more available could be to include CLnAs in frequently consumed food items. A different approach would be the production of enriched food supplements that could be taken up by cancer patients. However, as an oral intake of PunA would mainly lead to its incorporation into triglycerides as part of complex lipids (i.e., chylomicrons and lipoproteins), whether cancer cells are able to take up PunA in the form of triglycerides should be carefully investigated. Such enriched food products and supplements open up new opportunities to promote the use of CLnAs as health beneficial phytochemicals in the context of cancer prevention and treatment. Further studies are, however, needed to assess whether PunA-induced lipid peroxidation may cause adverse effects on the long term.

    The entry is from 10.3390/nu13082751

    References

    1. Dhar Dubey, K.K.; Sharma, G.; Kumar, A. Conjugated Linolenic Acids: Implication in Cancer. J. Agric. Food Chem. 2019, 67, 6091–6101.
    2. Gasmi, J.; Sanderson, J.T. Jacaric Acid and Its Octadecatrienoic Acid Geoisomers Induce Apoptosis Selectively in Cancerous Human Prostate Cells: A Mechanistic and 3-D Structure–Activity Study. Phytomedicine 2013, 20, 734–742.
    3. Dierge, E.; Larondelle, Y.; Feron, O. Cancer Diets for Cancer Patients: Lessons from Mouse Studies and New Insights from the Study of Fatty Acid Metabolism in Tumors. Biochimie 2020, 178, 56–68.
    4. Hennessy, A.A.; Ross, P.R.; Fitzgerald, G.F.; Stanton, C. Sources and Bioactive Properties of Conjugated Dietary Fatty Acids. Lipids 2016, 51, 377–397.
    5. Schneider, A.-C.; Mignolet, E.; Schneider, Y.-J.; Larondelle, Y. Uptake of Conjugated Linolenic Acids and Conversion to Cis-9, Trans-11-or Trans-9, Trans-11-conjugated Linoleic Acids in Caco-2 Cells. Br. J. Nutr. 2013, 109, 57–64.
    6. Schneider, A.-C.; Beguin, P.; Bourez, S.; Perfield, J.W.; Mignolet, E.; Debier, C.; Schneider, Y.-J.; Larondelle, Y. Conversion of T11t13 CLA into C9t11 CLA in Caco-2 Cells and Inhibition by Sterculic Oil. PLoS ONE 2012, 7, e32824.
    7. Shinohara, N.; Tsuduki, T.; Ito, J.; Honma, T.; Kijima, R.; Sugawara, S.; Arai, T.; Yamasaki, M.; Ikezaki, A.; Yokoyama, M.; et al. Jacaric Acid, a Linolenic Acid Isomer with a Conjugated Triene System, Has a Strong Antitumor Effect in Vitro and in Vivo. Biochim. Biophys. Acta Mol. Cell Biol. Lipids 2012, 1821, 980–988.
    8. Ngo Njembe, M.T.; Dormal, E.; Gardin, C.; Mignolet, E.; Debier, C.; Larondelle, Y. Effect of the Dietary Combination of Flaxseed and Ricinodendron Heudelotii or Punica Granatum Seed Oil on the Fatty Acid Profile of Eggs. Food Chem. 2021, 344, 128668.
    9. Lee, K.N.; Kritchevsky, D.; Pariza, M.W. Conjugated Linoleic Acid and Atherosclerosis in Rabbits. Atherosclerosis 1994, 108, 19–25.
    10. Benjamin, S.; Spener, F. Conjugated Linoleic Acids as Functional Food: An Insight into Their Health Benefits. Nutr. Metab. 2009, 6, 36.
    11. den Hartigh, L.J. Conjugated Linoleic Acid Effects on Cancer, Obesity, and Atherosclerosis: A Review of Pre-Clinical and Human Trials with Current Perspectives. Nutrients 2019, 11, 370.
    12. Yang, B.; Chen, H.; Stanton, C.; Ross, R.; Zhang, H.; Chen, Y.; Chen, W. Review of the Roles of Conjugated Linoleic Acid in Health and Disease. J. Funct. Foods 2015, 15, 314–325.
    13. de Carvalho, E.B.T.; de Melo, I.L.P.; Mancini-Filho, J. Chemical and Physiological Aspects of Isomers of Conjugated Fatty Acids. Food Sci. Technol. 2010, 30, 295–307.
    14. Fontes, A.L.; Pimentel, L.L.; Simões, C.D.; Gomes, A.M.P.; Rodríguez-Alcalá, L.M. Evidences and Perspectives in the Utilization of CLNA Isomers as Bioactive Compounds in Foods. Crit. Rev. Food Sci. Nutr. 2017, 57, 2611–2622.
    15. Boussetta, T.; Raad, H.; Lettéron, P.; Gougerot-Pocidalo, M.-A.; Marie, J.-C.; Driss, F.; El-Benna, J. Punicic Acid a Conjugated Linolenic Acid Inhibits TNFalpha-Induced Neutrophil Hyperactivation and Protects from Experimental Colon Inflammation in Rats. PLoS ONE 2009, 4, e6458.
    16. Shabbir, M.A.; Khan, M.R.; Saeed, M.; Pasha, I.; Khalil, A.A.; Siraj, N. Punicic Acid: A Striking Health Substance to Combat Metabolic Syndromes in Humans. Lipids Health Dis. 2017, 16, 99.
    17. Zamora-López, K.; Noriega, L.G.; Estanes-Hernández, A.; Escalona-Nández, I.; Tobón-Cornejo, S.; Tovar, A.R.; Barbero-Becerra, V.; Pérez-Monter, C. Punica Granatum L.-Derived Omega-5 Nanoemulsion Improves Hepatic Steatosis in Mice Fed a High Fat Diet by Increasing Fatty Acid Utilization in Hepatocytes. Sci. Rep. 2020, 10, 15229.
    18. Chen, P.-H.; Chen, G.-C.; Yang, M.-F.; Hsieh, C.-H.; Chuang, S.-H.; Yang, H.-L.; Kuo, Y.-H.; Chyuan, J.-H.; Chao, P.-M. Bitter Melon Seed Oil—Attenuated Body Fat Accumulation in Diet-Induced Obese Mice Is Associated with CAMP-Dependent Protein Kinase Activation and Cell Death in White Adipose Tissue. J. Nutr. 2012, 142, 1197–1204.
    19. Vroegrijk, I.O.C.M.; van Diepen, J.A.; van den Berg, S.; Westbroek, I.; Keizer, H.; Gambelli, L.; Hontecillas, R.; Bassaganya-Riera, J.; Zondag, G.C.M.; Romijn, J.A.; et al. Pomegranate Seed Oil, a Rich Source of Punicic Acid, Prevents Diet-Induced Obesity and Insulin Resistance in Mice. Food Chem. Toxicol. Int. J. Publ. Br. Ind. Biol. Res. Assoc. 2011, 49, 1426–1430.
    20. Anusree, S.S.; Sindhu, G.; Preetha Rani, M.R.; Raghu, K.G. Insulin Resistance in 3T3-L1 Adipocytes by TNF-α Is Improved by Punicic Acid through Upregulation of Insulin Signalling Pathway and Endocrine Function, and Downregulation of Proinflammatory Cytokines. Biochimie 2018, 146, 79–86.
    21. Yuan, G.-F.; Chen, X.-E.; Li, D. Conjugated Linolenic Acids and Their Bioactivities: A Review. Food Funct. 2014, 5, 1360.
    22. Tsuzuki, T.; Kawakami, Y. Tumor Angiogenesis Suppression by α-Eleostearic Acid, a Linolenic Acid Isomer with a Conjugated Triene System, via Peroxisome Proliferator-Activated Receptor γ. Carcinogenesis 2008, 29, 797–806.
    23. Yasui, Y.; Hosokawa, M.; Sahara, T.; Suzuki, R.; Ohgiya, S.; Kohno, H.; Tanaka, T.; Miyashita, K. Bitter Gourd Seed Fatty Acid Rich in 9c,11t,13t-Conjugated Linolenic Acid Induces Apoptosis and up-Regulates the GADD45, P53 and PPARγ in Human Colon Cancer Caco-2 Cells. Prostaglandins Leukot. Essent. Fat. Acids 2005, 73, 113–119.
    24. Grossmann, M.E.; Mizuno, N.K.; Schuster, T.; Cleary, M.P. Cleary Punicic Acid Is an ω-5 Fatty Acid Capable of Inhibiting Breast Cancer Proliferation. Int. J. Oncol. 2009, 36.
    25. Suzuki, R.; Noguchi, R.; Ota, T.; Abe, M.; Miyashita, K.; Kawada, T. Cytotoxic Effect of Conjugated Trienoic Fatty Acids on Mouse Tumor and Human Monocytic Leukemia Cells. Lipids 2001, 36, 477–482.
    26. Gasmi, J.; Sanderson, J.T. Growth Inhibitory, Antiandrogenic, and Pro-Apoptotic Effects of Punicic Acid in LNCaP Human Prostate Cancer Cells. J. Agric. Food Chem. 2010, 58, 12149–12156.
    27. Kohno, H.; Yasui, Y.; Suzuki, R.; Hosokawa, M.; Miyashita, K.; Tanaka, T. Dietary Seed Oil Rich in Conjugated Linolenic Acid from Bitter Melon Inhibits Azoxymethane-Induced Rat Colon Carcinogenesis through Elevation of Colonic PPAR? Expression and Alteration of Lipid Composition. Int. J. Cancer 2004, 110, 896–901.
    28. Wang, L.; Li, W.; Lin, M.; Garcia, M.; Mulholland, D.; Lilly, M.; Martins-Green, M. Luteolin, Ellagic Acid and Punicic Acid Are Natural Products That Inhibit Prostate Cancer Metastasis. Carcinogenesis 2014, 35, 2321–2330.
    29. Yang, L.; Cao, Y.; Chen, J.-N.; Chen, Z.-Y. Oxidative Stability of Conjugated Linolenic Acids. J. Agric. Food Chem. 2009, 57, 4212–4217.
    30. Dixon, S.J.; Lemberg, K.M.; Lamprecht, M.R.; Skouta, R.; Zaitsev, E.M.; Gleason, C.E.; Patel, D.N.; Bauer, A.J.; Cantley, A.M.; Yang, W.S.; et al. Ferroptosis: An Iron-Dependent Form of Nonapoptotic Cell Death. Cell 2012, 149, 1060–1072.
    31. Friedmann Angeli, J.P.; Schneider, M.; Proneth, B.; Tyurina, Y.Y.; Tyurin, V.A.; Hammond, V.J.; Herbach, N.; Aichler, M.; Walch, A.; Eggenhofer, E.; et al. Inactivation of the Ferroptosis Regulator Gpx4 Triggers Acute Renal Failure in Mice. Nat. Cell Biol. 2014, 16, 1180–1191.
    32. Hassannia, B.; Vandenabeele, P.; Vanden Berghe, T. Targeting Ferroptosis to Iron Out Cancer. Cancer Cell 2019, 35, 830–849.
    33. Stockwell, B.R.; Friedmann Angeli, J.P.; Bayir, H.; Bush, A.I.; Conrad, M.; Dixon, S.J.; Fulda, S.; Gascón, S.; Hatzios, S.K.; Kagan, V.E.; et al. Ferroptosis: A Regulated Cell Death Nexus Linking Metabolism, Redox Biology, and Disease. Cell 2017, 171, 273–285.
    34. Cao, J.Y.; Dixon, S.J. Mechanisms of Ferroptosis. Cell. Mol. Life Sci. 2016, 73, 2195–2209.
    35. Conrad, M.; Pratt, D.A. The Chemical Basis of Ferroptosis. Nat. Chem. Biol. 2019, 15, 1137–1147.
    36. Jiang, X.; Stockwell, B.R.; Conrad, M. Ferroptosis: Mechanisms, Biology and Role in Disease. Nat. Rev. Mol. Cell Biol. 2021, 22, 266–282.
    37. Doll, S.; Freitas, F.P.; Shah, R.; Aldrovandi, M.; da Silva, M.C.; Ingold, I.; Goya Grocin, A.; da Silva, T.N.X.; Panzilius, E.; Scheel, C.H.; et al. FSP1 Is a Glutathione-Independent Ferroptosis Suppressor. Nature 2019, 575, 693–698.
    38. Sun, W.-Y.; Tyurin, V.A.; Mikulska-Ruminska, K.; Shrivastava, I.H.; Anthonymuthu, T.S.; Zhai, Y.-J.; Pan, M.-H.; Gong, H.-B.; Lu, D.-H.; Sun, J.; et al. Phospholipase IPLA2β Averts Ferroptosis by Eliminating a Redox Lipid Death Signal. Nat. Chem. Biol. 2021, 17, 465–476.
    39. Shah, R.; Shchepinov, M.S.; Pratt, D.A. Resolving the Role of Lipoxygenases in the Initiation and Execution of Ferroptosis. ACS Cent. Sci. 2018, 4, 387–396.
    40. Yang, W.S.; Kim, K.J.; Gaschler, M.M.; Patel, M.; Shchepinov, M.S.; Stockwell, B.R. Peroxidation of Polyunsaturated Fatty Acids by Lipoxygenases Drives Ferroptosis. Proc. Natl. Acad. Sci. USA 2016, 113, E4966–E4975.
    41. Wenzel, S.E.; Tyurina, Y.Y.; Zhao, J.; St. Croix, C.M.; Dar, H.H.; Mao, G.; Tyurin, V.A.; Anthonymuthu, T.S.; Kapralov, A.A.; Amoscato, A.A.; et al. PEBP1 Wardens Ferroptosis by Enabling Lipoxygenase Generation of Lipid Death Signals. Cell 2017, 171, 628–641.e26.
    42. Zou, Y.; Li, H.; Graham, E.T.; Deik, A.A.; Eaton, J.K.; Wang, W.; Sandoval-Gomez, G.; Clish, C.B.; Doench, J.G.; Schreiber, S.L. Cytochrome P450 Oxidoreductase Contributes to Phospholipid Peroxidation in Ferroptosis. Nat. Chem. Biol. 2020, 16, 302–309.
    43. Yagoda, N.; von Rechenberg, M.; Zaganjor, E.; Bauer, A.J.; Yang, W.S.; Fridman, D.J.; Wolpaw, A.J.; Smukste, I.; Peltier, J.M.; Boniface, J.J.; et al. RAS–RAF–MEK-Dependent Oxidative Cell Death Involving Voltage-Dependent Anion Channels. Nature 2007, 447, 865–869.
    44. Yang, W.S.; Stockwell, B.R. Synthetic Lethal Screening Identifies Compounds Activating Iron-Dependent, Nonapoptotic Cell Death in Oncogenic-RAS-Harboring Cancer Cells. Chem. Biol. 2008, 15, 234–245.
    45. Dolma, S.; Lessnick, S.L.; Hahn, W.C.; Stockwell, B.R. Identification of Genotype-Selective Antitumor Agents Using Synthetic Lethal Chemical Screening in Engineered Human Tumor Cells. Cancer Cell 2003, 3, 285–296.
    46. Perez, M.A.; Magtanong, L.; Dixon, S.J.; Watts, J.L. Dietary Lipids Induce Ferroptosis in Caenorhabditiselegans and Human Cancer Cells. Dev. Cell 2020, 54, 447–454.e4.
    47. Doll, S.; Proneth, B.; Tyurina, Y.Y.; Panzilius, E.; Kobayashi, S.; Ingold, I.; Irmler, M.; Beckers, J.; Aichler, M.; Walch, A.; et al. ACSL4 Dictates Ferroptosis Sensitivity by Shaping Cellular Lipid Composition. Nat. Chem. Biol. 2017, 13, 91–98.
    48. Kagan, V.E.; Mao, G.; Qu, F.; Angeli, J.P.F.; Doll, S.; Croix, C.S.; Dar, H.H.; Liu, B.; Tyurin, V.A.; Ritov, V.B.; et al. Oxidized Arachidonic and Adrenic PEs Navigate Cells to Ferroptosis. Nat. Chem. Biol. 2017, 13, 81–90.
    49. Beatty, A.; Singh, T.; Tyurina, Y.Y.; Tyurin, V.A.; Samovich, S.; Nicolas, E.; Maslar, K.; Zhou, Y.; Cai, K.Q.; Tan, Y.; et al. Ferroptotic Cell Death Triggered by Conjugated Linolenic Acids Is Mediated by ACSL1. Nat. Commun. 2021, 12, 2244.
    50. Dierge, E.; Debock, E.; Guilbaud, C.; Corbet, C.; Mignolet, E.; Mignard, L.; Bastien, E.; Dessy, C.; Larondelle, Y.; Feron, O. Peroxidation of N-3 and n-6 Polyunsaturated Fatty Acids in the Acidic Tumor Environment Leads to Ferroptosis-Mediated Anticancer Effects. Cell Metab. 2021, 33, 1701–1715.e5.
    51. Bray, F.; Ferlay, J.; Soerjomataram, I.; Siegel, R.L.; Torre, L.A.; Jemal, A. Global Cancer Statistics 2018: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA Cancer J. Clin. 2018, 68, 394–424.
    52. Hangauer, M.J.; Viswanathan, V.S.; Ryan, M.J.; Bole, D.; Eaton, J.K.; Matov, A.; Galeas, J.; Dhruv, H.D.; Berens, M.E.; Schreiber, S.L.; et al. Drug-Tolerant Persister Cancer Cells Are Vulnerable to GPX4 Inhibition. Nature 2017, 551, 247–250.
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