Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Overexpression of the P-glycoprotein/multidrug resistance 1 (MDR1) and multidrug resistance protein 1 (MRP1) gene is closely associated with the clinical outcome of various malignancies, and it is involved in responses to some anticancer chemotherapeutic agents including doxorubicin. Six human MRP subfamily members (MRP2-7) with structural similarities to MRP1 have been identified. Recently, the relationships between MRP2 and MRP3 expression levels of some cancer cells and drug sensitivity to doxorubicin have been reported, but the relationship between the clinical samples and drug sensitivity remains unclear. We determined the expressions of the MDR1, MRP1, MRP2 and MRP3 gene in bladder cancer during the clinical course and sought to learn whether the expression was correlated with drug responses to doxorubicin. Doxorubicin, used in chemotherapeutic treatment including intravesical and systemic chemotherapy, is an important anticancer agent for the treatment of bladder cancer. We used quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis for our study, and the sensitivity to doxorubicin in bladder cancer was determined using the in vitro succinate dehydrogenase inhibition test. Using 47 clinical samples of bladder cancer, we confirmed the significant correlation of MDR1, MRP1 and MRP3 mRNA levels with resistance to doxorubicin. We showed that the expression of MDR1, MRP1, MRP2 and MRP3 in recurrent tumors and residual tumors after chemotherapeutic treatment was higher than that in untreated primary tumors. In particular, the MDR1 expression in residual tumors was 5.7-fold higher than that in untreated primary tumors.
Int J Cancer 2002 Apr 01
PMID:Increased expression of multidrug resistance-associated proteins in bladder cancer during clinical course and drug resistance to doxorubicin. 1192 Jun 26

Mitochondrial defects have been associated with neurological disorders, as well as cancers. Two ubiquitously expressed mitochondrial enzymes--succinate dehydrogenase (SDH) and fumarate hydratase (FH, fumarase)--catalyse sequential steps in the Krebs tricarboxylic-acid cycle. Inherited heterozygous mutations in the genes encoding these enzymes cause predispositions to two types of inherited neoplasia syndromes that do not share any component tumours. Homozygous mutations in the same genes result in severe neurological impairment. Understanding this link between inherited cancer syndromes and neurological disease could provide further insights into the mechanisms by which mitochondrial deficiencies lead to tumour development.
Nat Rev Cancer 2003 Mar
PMID:A role for mitochondrial enzymes in inherited neoplasia and beyond. 1261 54

Mitochondrial DNA (mtDNA) mutations occur in a variety of human cancers, suggesting a possible role for mitochondrial respiratory functions in tumorigenesis. Recent studies have demonstrated that SDHD, a nuclear gene encoding one of the mitochondrial complex II subunits, acts as a tumor-suppressor for hereditary paragangliomas and pheochromocytomas. In order to determine whether the SDHD function plays a wider role in human malignancies, we examined SDHD gene alterations in 52 colorectal and 59 gastric cancers and 7 cancer cell lines. Loss of heterozygosity (LOH) at the SDHD gene locus was found in 5 of 35 (14%) colorectal and 5 of 40 (13%) gastric cancers. Reduced SDHD gene expression, which was partly associated with SDHD gene LOH, was observed in 15 of 19 (79%) colorectal cancers examined. Unlike classical tumor-suppressor genes, however, partial loss rather than complete loss of the SDHD gene expression was preferentially observed and the reduced expression could not result from CpG-island methylation or coding mutation. Interestingly, the mtDNA mutations (12 cases) and the SDHD gene LOH (6 of 7 cases) did not occur in the same cancers, suggesting that these alterations might have similar functional effects in tumorigenesis. We suggest that SDHD alterations can affect mitochondrial respiratory chain functions and play a role in colorectal and gastric cancers as a distinct type of tumor suppressor.
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PMID:Reduced expression and loss of heterozygosity of the SDHD gene in colorectal and gastric cancer. 1288 10

Pheochromocytomas and paragangliomas are tumors of the autonomic nervous system; pheochromocytomas are tumors of the adrenal medulla, and paragangliomas are extra-adrenal tumors arising from either the sympathetic nervous system or parasympathetic ganglia. It has previously been estimated that approximately 10%-15% of pheochromocytomas are due to hereditary causes. However, our increased understanding of the three hereditary syndromes (neurofibromatosis 1, multiple endocrine neoplasia type 2, and von Hippel-Lindau syndrome) in which pheochromocytoma is found and the recent discovery that mutations in genes in the succinate dehydrogenase family (SDHB and SDHD) predispose to pheochromocytoma have necessitated a re-evaluation of the genetic basis of pheochromocytoma. These studies indicate that the frequency of germline mutations associated with isolated pheochromocytoma is higher than previously estimated, with both hospital-based series and a large population-based series indicating that the frequency of germline mutations in RET, VHL, SDHB, and SDHD taken together approximates 20%. In all patients with pheochromocytoma, including those with known hereditary syndrome or a positive family history, the frequency of germline mutations in these four genes together approaches 30%. Given the frequency of germline mutations, consideration should be given to genetic counseling for all patients with pheochromocytoma and is particularly important for individuals with a positive family history, multifocal disease, or a diagnosis before age 50. Identification of patients with hereditary pheochromocytoma is important because it can guide medical management in mutation-positive patients and their families. This review provides an overview of the known genetic syndromes that are commonly associated with pheochromocytoma, examines recent data on the association of germline mutations in the succinate dehydrogenase gene family with pheochromocytoma, and suggests guidelines for the genetic evaluation of pheochromocytoma patients.
J Natl Cancer Inst 2003 Aug 20
PMID:Pheochromocytoma: the expanding genetic differential diagnosis. 1292 44

Germ-line mutations in the genes encoding succinate dehydrogenase complex subunits B (SDHB) and D (SDHD) have been reported in familial paragangliomas and apparently sporadic phaeochromocytomas (ASP), but the genotype-phenotype relationships of these mutations are unknown. Eighty-four patients (all but 2 followed up for 8.8 +/- 5.7 years) with ASP (57 with adrenal tumors, 27 with extra-adrenal, multiple, malignant, or recurrent tumors) were screened for the major susceptibility genes for phaeochromocytoma (RET, VHL, SDHD, and SDHB). Thirty-three tumors were available for molecular analysis, enzyme assays, and immunohistochemistry. No (0%) RET and 2 (2.4%) VHL mutations were detected. Only two coding single nucleotide polymorphisms in the SDHD gene (G12S and H50R) were found in 6 patients (7%). Conversely, six deleterious mutations in the SDHB gene were identified in 8 patients (9.5%). Ectopic site and recurrence or malignancy were strongly associated with SDHB mutations (7 of 8, 87%, versus 20 of 76, 26%; P = 0.001). Somatic DNA analysis indicated a loss of heterozygosity at chromosome 1p36 (SDHB locus) in 16 of 33 cases (48%). A loss of heterozygosity at the SDHB locus was found in all tumors with SDHB mutation, and assays of respiratory chain enzymes showed a complete loss of complex II catalytic activity. The vascular architecture of tumors with SDHB mutations displayed features typical of malignancy. These data strongly suggest that SDHB gene is a tumor suppressor gene and that the identification of germ-line mutations in SDHB gene in patients with ASPs should be considered as a high-risk factor for malignancy or recurrence.
Cancer Res 2003 Sep 01
PMID:Mutations in the SDHB gene are associated with extra-adrenal and/or malignant phaeochromocytomas. 1450 Apr 3

Paragangliomas of the head and neck region are a group of rare, usually benign, slow-growing tumors developing from paraganglionic chemoreceptors in most patients. Mutations in a subunit of the mitochondrial enzyme II complex (succinate dehydrogenase [SDHD]) were shown to be responsible for the formation of paragangliomas. In addition, loss of heterozygosity (LOH) on chromosome 11, mainly in 11q23 (PGL1), was observed recently. We analyzed DNA derived from tumor sections of three unrelated paraganglioma patients (one case with multiple paragangliomas, two cases with single tumors; all of them sporadic cases) for mutations in the SDHD gene by direct sequencing. Microsatellite-based LOH was performed, and events of chromosomal loss were validated by fluorescence in situ hybridization (FISH) on paraffin-embedded tumor and normal tissue by using centromeric satellite DNA. Sequence analysis revealed mutations in SDHD exon 1 in all patients, affecting the initiation codon (M1V). Another alteration was detected in exon 2 but was lacking in tumor DNA and therefore classified as polymorphism (H50R). LOH and FISH analyses demonstrated partial/total monosomy for chromosome 11 in the tumor samples tested. A common genetic mechanism appears to be the pathophysiologic basis for sporadic tumor development because the proposed two-hit model comprising both LOH and point mutation is manifest in our patients. Loss of chromosome 11 regions, including the deletion of PGL1 and PGL2 loci, may result in a more severe phenotype, as exemplified by the development of multiple tumors in one of the patients.
Cancer Genet Cytogenet 2004 Apr 15
PMID:Chromosome 11 monosomy in conjunction with a mutated SDHD initiation codon in nonfamilial paraganglioma cases. 1506 20

Endocrine surgeons should maintain a high index of suspicion when patients are diagnosed with clinical signs or symptoms of parathyroid carcinoma. Although rare, the best chance for cure of these patients is at the time of the initial operation. Surgical resection of recurrent disease can provide effective palliation and can sometimes be assisted using gamma-probe directed dissection of sestamibi-labeled tumor tissue. Treatment of hyperparathyroidism in the setting of multiple endocrine neoplasia type 1 (MEN-1), particularly in the reoperative setting, can be aided by using the rapid intraoperative parathyroid hormone assay to judge the adequacy of parathyroid debulking. In addition, in selected cases, the gamma probe can assist in identifying the location of ectopic or autografted sestamibi-labeled parathyroid tissue. Patients with incidental adrenal masses rarely require fine needle aspiration to exclude metastatic cancer. Fine needle aspiration, if performed, should never precede hormone evaluation to exclude pheochromocytoma. Patients who are diagnosed with incidental adrenal masses in the setting of a prior or concurrent cancer diagnosis are equally likely to have a primary adrenal mass as they would be to have metastatic cancer in the adrenal gland. Pheochromocytomas occasionally develop in patients with MEN-1. In suspicious cases, molecular identification of an MEN-1 mutation can be used to confirm the diagnosis. Preoperative hormone evaluation of a patient with an adrenal incidentaloma should include evaluation for subclinical Cushing's syndrome through an overnight 1-mg dexamethasone suppression test. Identification of this condition allows for safe peri- and postoperative steroid hormone replacement, with very slow withdrawal of exogenous steroids to allow the opposite adrenal gland to recover and avoid postoperative Addisonian crisis. Paragangliomas are more commonly multifocal and malignant compared to pheochromocytomas. Evaluation of patients with paragangliomas should include radiographic staging for multifocality and metastatic disease, and postoperative hormone and radiographic follow-up evaluation should be performed. Consideration should be given to genetic testing for von Hippel-Lindau and succinate dehydrogenase mutations. Surgical treatment of rare functioning pancreatic and duodenal endocrine tumors, such as metastatic sporadic insulinoma and MEN-1-associated gastrinoma, can provide effective palliation. Surgical treatment should be integrated into a comprehensive treatment scheme that recognizes the natural history of the disease and incorporates appropriate adjunctive therapies and follow-up strategies.
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PMID:Unusual functioning endocrine tumors. 1523 9

Germline mutations in the succinate dehydrogenase (SDH) (mitochondrial respiratory chain complex II) subunit B gene, SDHB, cause susceptibility to head and neck paraganglioma and phaeochromocytoma. Previously, we did not identify somatic SDHB mutations in sporadic phaeochromocytoma, but SDHB maps to 1p36, a region of frequent loss of heterozygosity (LOH) in neuroblastoma as well. Hence, to evaluate SDHB as a candidate neuroblastoma tumour suppressor gene (TSG) we performed mutation analysis in 46 primary neuroblastomas by direct sequencing, but did not identify germline or somatic SDHB mutations. As TSGs such as RASSF1A are frequently inactivated by promoter region hypermethylation, we designed a methylation-sensitive PCR-based assay to detect SDHB promoter region methylation. In 21% of primary neuroblastomas and 32% of phaeochromocytomas (32%) methylated (and unmethylated) alleles were detected. Although promoter region methylation was also detected in two neuroblastoma cell lines, this was not associated with silencing of SDHB expression, and treatment with a demethylating agent (5-azacytidine) did not increase SDH activity. These findings suggest that although germline SDHB mutations are an important cause of phaeochromocytoma susceptibility, somatic inactivation of SDHB does not have a major role in sporadic neural crest tumours and SDHB is not the target of 1p36 allele loss in neuroblastoma and phaeochromocytoma.
Br J Cancer 2004 Nov 15
PMID:Investigation of the role of SDHB inactivation in sporadic phaeochromocytoma and neuroblastoma. 1550 28

Medullary thyroid carcinoma (MTC) is a tumor that arises from parafollicular cells of the thyroid gland. MTC can occur sporadically (75%) or as part of inherited cancer syndromes (25%). In most cases, hereditary MTC evolves from preneoplastic C cell hyperplasia (CCH), so early detection of this pathology would evidently be critical. A recent study reports that alterations in succinate dehydrogenase (SDH) D are responsible for familial non-RET CCH. First, we studied SDHD in two families with hereditary non-RET CCH and found no alterations related to the inheritance of this disease. Then, we investigated whether the H50R variant could be a risk factor in the sporadic development of MTC in both Spanish and English patients. We found no evidence that the presence of the H50R is strongly associated with the risk of sporadic MTC, although we did observe an association with age at diagnosis of MTC in Spanish H50R carriers that we did not find in English patients. Finally, we looked for evidence of CCH or any other thyroid disease in a panel of germ-line SDH (B or D) mutation carriers and found none. We conclude that SDHD variants do not constitute a risk factor for developing CCH or sporadic MTC.
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PMID:Succinate dehydrogenase D variants do not constitute a risk factor for developing C cell hyperplasia or sporadic medullary thyroid carcinoma. 1562 5

Several mitochondrial proteins are tumor suppressors. These include succinate dehydrogenase (SDH) and fumarate hydratase, both enzymes of the tricarboxylic acid (TCA) cycle. However, to date, the mechanisms by which defects in the TCA cycle contribute to tumor formation have not been elucidated. Here we describe a mitochondrion-to-cytosol signaling pathway that links mitochondrial dysfunction to oncogenic events: succinate, which accumulates as a result of SDH inhibition, inhibits HIF-alpha prolyl hydroxylases in the cytosol, leading to stabilization and activation of HIF-1alpha. These results suggest a mechanistic link between SDH mutations and HIF-1alpha induction, providing an explanation for the highly vascular tumors that develop in the absence of VHL mutations.
Cancer Cell 2005 Jan
PMID:Succinate links TCA cycle dysfunction to oncogenesis by inhibiting HIF-alpha prolyl hydroxylase. 1565 51


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