fumaric-acid and Kidney-Neoplasms

While performing surgical treatment of the localized form of renal cell cancer by means of open or laparoscopic partial nephrectomy, renal warm ischemia is an important issue. Using renal warm ischemia allows to prevent parenchymal bleeding, to optimize conditions for resection of the tumor and to increase significantly the efficiency of hemostasis. However, an important problem is the probability of ischemic hypoxic damage of the remaining part of the kidney tissue during renal warm ischemia and renal functional impairment in the postoperative period.. To compare nephroprotective activity of sodium fumarate, mannitol and furosemide using experimental model of 30- and 60-minute renal warm ischemia in rabbits.. The experiments were carried out on 360 conventional male-rabbits of the "Chinchilla" breed weighed 2,6+/-0,3 kg which were allocated into 10 groups. The control group No1 included intact animals, the control group No2 included the rabbits in which renal artery was not clamped. For the animals from the trial groups (No3-No10) the experimental model of 30- and 60-minute renal warm ischemia was used. In groups No3 and No4 no drugs were provided. Other rabbits undergone renal warm ischemia with a protection by sodium fumarate (groups No5 and No6 - 1,5 ml/kg IV), lasix (groups No7 and No8 - 3,0 mg/kg IV) and mannitol (No9 and No10 - 1,0 g/kg IV). The influence of renal warm ischemia on the renal tissue ultrastructure and the levels of NGAL, Cystatin-C and creatinine in blood and urine were studied.. During experimental pharmacologically uncorrected 30-minute renal warm ischemia in animals, edema of the terminal part of microvilli of the proximal tubules epithelium, an increase of lysosome number in the hyaloplasm of epithelial cells, appearance of flaky content of medium electronic density in the lumens of distal tubules and collecting tubules, as well as sharp peak-like increase of NGAL and cystatin-C in blood and urine were observed. Increasing the time of ischemia up to 60 minutes was accompanied by more severe disturbances. In groups where sodium fumarate, lasix and mannitol were used the observed ultrastructural disturbances were expressed to lesser extent, whereas sodium fumarate demonstrated the best nephroprotective activity. After using mannitol the severity of disturbances was less than in the groups where mannitol, lasix or sodium fumarate were not given. Lasix and sodium salt of fumaric acid showed a higher nephroprotective activity. The best results were received in the animals received sodium fumarate.. The studied drugs provided a nephroprotective effect regarding ischemia of rabbit kidney. The effect of sodium fumarate was the most pronounced, followed by furosemide and, to a lesser extent, mannitol. Use of sodium fumarate allows to protect and stimulate the kidney tissue effectively during oxygen deprivation under ischemic state.

Topics: Animals; Female; Fumarates; Furosemide; Humans; Ischemia; Kidney; Kidney Neoplasms; Lipocalin-2; Male; Mannitol; Rabbits; Warm Ischemia

Mutations of the tricarboxylic acid cycle enzyme fumarate hydratase cause hereditary leiomyomatosis and renal cell cancer. Fumarate hydratase-deficient renal cancers are highly aggressive and metastasize even when small, leading to a very poor clinical outcome. Fumarate, a small molecule metabolite that accumulates in fumarate hydratase-deficient cells, plays a key role in cell transformation, making it a bona fide oncometabolite. Fumarate has been shown to inhibit α-ketoglutarate-dependent dioxygenases that are involved in DNA and histone demethylation. However, the link between fumarate accumulation, epigenetic changes, and tumorigenesis is unclear. Here we show that loss of fumarate hydratase and the subsequent accumulation of fumarate in mouse and human cells elicits an epithelial-to-mesenchymal-transition (EMT), a phenotypic switch associated with cancer initiation, invasion, and metastasis. We demonstrate that fumarate inhibits Tet-mediated demethylation of a regulatory region of the antimetastatic miRNA cluster mir-200ba429, leading to the expression of EMT-related transcription factors and enhanced migratory properties. These epigenetic and phenotypic changes are recapitulated by the incubation of fumarate hydratase-proficient cells with cell-permeable fumarate. Loss of fumarate hydratase is associated with suppression of miR-200 and the EMT signature in renal cancer and is associated with poor clinical outcome. These results imply that loss of fumarate hydratase and fumarate accumulation contribute to the aggressive features of fumarate hydratase-deficient tumours.

Topics: Animals; Cell Movement; Cells, Cultured; Epigenesis, Genetic; Epithelial-Mesenchymal Transition; Fumarate Hydratase; Fumarates; HEK293 Cells; Humans; Kidney Neoplasms; Mesoderm; Mice; MicroRNAs; Transcription Factors; Transcriptome

The gene encoding the Krebs cycle enzyme fumarate hydratase (FH) is mutated in hereditary leiomyomatosis and renal cell cancer (HLRCC). Loss of FH activity causes accumulation of intracellular fumarate, which can directly modify cysteine residues to form 2-succinocysteine through succination. We undertook a proteomic-based screen in cells and renal cysts from Fh1 (murine FH)-deficient mice and identified 94 protein succination targets. Notably, we identified the succination of three cysteine residues in mitochondrial Aconitase2 (ACO2) crucial for iron-sulfur cluster binding. We show that fumarate exerts a dose-dependent inhibition of ACO2 activity, which correlates with increased succination as determined by mass spectrometry, possibly by interfering with iron chelation. Importantly, we show that aconitase activity is impaired in FH-deficient cells. Our data provide evidence that succination, resulting from FH deficiency, targets and potentially alters the function of multiple proteins and may contribute to the dysregulated metabolism observed in HLRCC.

Topics: Aconitate Hydratase; Animals; Cell Line; Cysteine; Fumarate Hydratase; Fumarates; Humans; Iron; Kidney Neoplasms; Leiomyomatosis; Mice; Mice, Transgenic; Mitochondria; Neoplastic Syndromes, Hereditary; Proteome; Skin Neoplasms; Succinic Acid; Uterine Neoplasms

Fumarate hydratase (FH) is an enzyme of the tricarboxylic acid cycle (TCA cycle) that catalyses the hydration of fumarate into malate. Germline mutations of FH are responsible for hereditary leiomyomatosis and renal-cell cancer (HLRCC). It has previously been demonstrated that the absence of FH leads to the accumulation of fumarate, which activates hypoxia-inducible factors (HIFs) at normal oxygen tensions. However, so far no mechanism that explains the ability of cells to survive without a functional TCA cycle has been provided. Here we use newly characterized genetically modified kidney mouse cells in which Fh1 has been deleted, and apply a newly developed computer model of the metabolism of these cells to predict and experimentally validate a linear metabolic pathway beginning with glutamine uptake and ending with bilirubin excretion from Fh1-deficient cells. This pathway, which involves the biosynthesis and degradation of haem, enables Fh1-deficient cells to use the accumulated TCA cycle metabolites and permits partial mitochondrial NADH production. We predicted and confirmed that targeting this pathway would render Fh1-deficient cells non-viable, while sparing wild-type Fh1-containing cells. This work goes beyond identifying a metabolic pathway that is induced in Fh1-deficient cells to demonstrate that inhibition of haem oxygenation is synthetically lethal when combined with Fh1 deficiency, providing a new potential target for treating HLRCC patients.

Topics: Animals; Bilirubin; Cell Line; Cells, Cultured; Citric Acid Cycle; Computer Simulation; Fumarate Hydratase; Fumarates; Genes, Lethal; Genes, Tumor Suppressor; Glutamine; Heme; Heme Oxygenase (Decyclizing); Kidney Neoplasms; Leiomyomatosis; Mice; Mitochondria; Mutation; NAD; Neoplastic Syndromes, Hereditary; Skin Neoplasms; Uterine Neoplasms

Individuals with hemizygous germline fumarate hydratase (FH) mutations are predisposed to renal cancer. These tumors predominantly exhibit functional inactivation of the remaining wild-type allele, implicating FH inactivation as a tumor-promoting event. Hypoxia-inducible factors are expressed in many cancers and are increased in clear cell renal carcinomas. Under normoxia, the HIFs are labile due to VHL-dependent proteasomal degradation, but stabilization occurs under hypoxia due to inactivation of HIF prolyl hydroxylase (HPH), which prevents HIF hydroxylation and VHL recognition. We demonstrate that FH inhibition, together with elevated intracellular fumarate, coincides with HIF upregulation. Further, we show that fumarate acts as a competitive inhibitor of HPH. These data delineate a novel fumarate-dependent pathway for regulating HPH activity and HIF protein levels.

Topics: Adult; Alleles; Basic Helix-Loop-Helix Transcription Factors; Carcinoma, Renal Cell; DNA-Binding Proteins; Female; Fumarate Hydratase; Fumarates; Gene Expression Regulation, Neoplastic; Humans; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Ketoglutaric Acids; Kidney Neoplasms; Leiomyomatosis; Male; Middle Aged; Nuclear Proteins; Procollagen-Proline Dioxygenase; Syndrome; Transcription Factors; Up-Regulation

Anticarcinogenic effects of the fumaric acid was studied in two rat models of carcinogenesis. Tumors of the esophagus, forestomach, tongue and throat were induced by peroral instillation of 35 mg/kg body weight N-methyl-N-benzylnitrosamine, and neurogenic and renal ones--by transplacental injection of 75 mg/kg body weight N-ethyl-N-nitrosourea. The fumaric acid given in drinking water in the dose of 1 g/l at the postinitiation stage of the carcinogenesis was shown to inhibit the development of esophageal papilloma, brain glioma and mesenchymal tumors of the kidney.

Topics: Animals; Anticarcinogenic Agents; Carcinogens; Chi-Square Distribution; Dimethylnitrosamine; Disease Models, Animal; Drug Screening Assays, Antitumor; Esophageal Neoplasms; Ethylnitrosourea; Female; Fumarates; Kidney Neoplasms; Male; Nervous System Neoplasms; Pregnancy; Prenatal Exposure Delayed Effects; Rats