1999;18:3793\3797. that lead to the difference in RCC development. We compared the Bivalirudin Trifluoroacetate protective responses in the kidney of and strains after Fe\NTA treatment. Empesertib After 3\week Fe\NTA treatment, mice maintained higher levels of expression of glutathione peroxidase 4 and mice had decreased expression of transferrin receptor and increased expression of ferritin to greater degrees than mice. After a single Fe\NTA injection, higher levels of oxidative cell damage and cytosolic catalytic Fe(II) were observed in mice, accompanied by a greater increase in lipocalin\2. Lipocalin\2 deficiency significantly decreased oxidative renal damage. Our results suggest that a genetic trait favoring ferroptosis resistance contributes to high susceptibility to Fe\NTA\induced RCC in strain. strain in 1987. 12 However, in the recent experiments using mice, the incidence of RCC was low ( 10%). 13 Therefore, it is necessary to clarify the mechanisms responsible for the inter\strain difference in susceptibility to Fe\NTA\induced renal carcinogenesis. In the first mouse carcinogenesis experiment with strain mice, mice were observed for only 60?weeks, whereas our recent experiment with the strain of mice followed all the mice for 120?weeks. In the present study, we performed the renal carcinogenesis experiment with mice, with all mice followed until the point of death to establish the inter\strain difference. Genomic DNA exposed to ROS may develop copy number aberrations and somatic mutations, which potentially are the basis for carcinogenesis. 14 ROS may affect specific chromosomal loci to provoke carcinogenesis. 15 The genome of Fe\NTA\induced rat RCC carries prominent chromosomal aberrations, which frequently include homozygous deletion of the tumor suppressor and amplification of the oncogene. 16 However, RCC induced in mice and background mice and mice or rats. We also analyzed acute/subacute responses to the Fe\NTA\induced renal damage in and mice to identify the underlying mechanism for the difference in susceptibility. We hypothesized that ferroptosis and iron metabolism are involved in the susceptibility to Fe\NTA\induced renal carcinogenesis. The catalytic Fe(II) in cytosol, called liable iron pool (LIP), can be highly reactive and produces various ROS. 17 , 18 Ferroptosis is a type of regulated cell death, defined as catalytic Fe(II)\dependent regulated necrosis accompanying lipid peroxidation. 19 Ferroptosis is regulated by cellular glutathione and glutathione Empesertib peroxidase 4 (GPX4) 20 as well as by iron regulatory/metabolizing proteins. Transferrin receptor 1 (TfR1), a membrane protein binding to the transferrin complex to uptake iron to cytoplasm, 21 not only controls the cellular iron level but can be a ferroptosis marker. 22 Lipocalin 2 (LCN2), also called neutrophil gelatinase\associated lipocalin (NGAL), is a small secreted protein that binds to iron via siderophores to promote cellular iron uptake or induce apoptosis to contribute to renal injury. 23 The early phase analyses suggested that inherent ferroptosis resistance of the renal tubular cells in mice determines the difference in carcinogenesis from mice. 2.?MATERIALS AND METHODS 2.1. Protocols for ferric nitrilotriacetate induced renal carcinogenesis in mice Ferric nitrate enneahydrate was Empesertib obtained from Wako, and nitrilotriacetic acid disodium salt was obtained from TCI (Tokyo, Japan); they were dissolved in deionized water to make 300 and 600?mM solutions, respectively. The solution of ferric nitrate enneahydrate and nitrilotriacetic acid disodium was mixed immediately before use to make Fe\NTA solution, with a ratio of 1 1:2 (v/v); the pH was adjusted to 7.4 with sodium carbonate (Wako). Finally, the Fe\NTA solution was diluted 10 times with deionized water. All the chemicals used were of analytical grade. From 4?weeks of age, 58?male mice were maintained under a standard diet at the laboratory animal facility of Nagoya University Graduate School of Medicine. All the mice were injected i.p. with Fe\NTA, with a dose of 5?mg iron/kg five times a week for the first 2?weeks, and injected.