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)

The phototoxicity of liposome-incorporated Zn(II)-phthalocyanine (ZnPc) and its water-soluble tetrasulphonated derivative (ZnPcTS) was studied in the tumorigenic but nonmetastatic (RE4) and the highly metastatic (4R) transformed rat embryo fibroblasts. Upon irradiation with 585-605 nm light in the presence of ZnPc, the cell survival drastically decreased, while it was unaffected by ZnPcTS. Enzymatic assays showed that ZnPc induced about a 60% decrease in the activity of the mitochondrial enzymes NADH and succinate dehydrogenase after 3 min of irradiation, while no significant reduction in the activity of lactate dehydrogenase and lysosomal N-acetyl-beta-glucosaminidase was observed. The transport of thymidine, deoxyglucose and alpha-aminoisobutyric acid through the plasma membrane was strongly inhibited after irradiation. Similarly, the intracellular ATP content was significantly reduced. The reduction of DNA biosynthesis showed a time dependence quite similar to the photo-induced decrease in cell survival. No repair of cellular functions affected by ZnPc was observed in the 2 cell lines. These results indicate that, under our experimental conditions, hydrophobic ZnPc exerts its cytotoxic activity mainly by impairing those functions localized in the plasma membrane of the cells.
Int J Cancer 1998 Jan 30
PMID:Photosensitization of cells with different metastatic potentials by liposome-delivered Zn(II)-phthalocyanine. 945 3

Preneoplastic liver foci and neoplasms of different morphological phenotypes were induced in rats with N-nitrosomorpholine (NNM; 120 mg/l in drinking water for 7 weeks) and the peroxisome proliferator dehydroepiandrosterone (DHEA; 0.6% in the diet for up to 84 weeks). Preneoplastic glycogen storage foci (GSF) occurred mainly upon treatment with NNM, and amphophilic cell foci (APF) were mainly observed in rats treated with DHEA alone or in combination with NNM. The 2 types of lesions belong to 2 different cellular lineages, the glycogenotic/basophilic lineage and the amphophilic lineage, which are characterized by distinct patterns of alterations in key enzymes of energy metabolism. Whereas in GSF enzymes of glucose metabolizing pathways were modified (increase in glucose-6-phosphate dehydrogenase and pyruvate kinase, decrease in glucose-6-phosphatase), APF mainly demonstrated alterations in mitochondrial enzymes (increase in cytochrome c oxidase, succinate dehydrogenase and glycerol-3-phosphate dehydrogenase) and, to a lower extent, in peroxisomal enzymes (increase in peroxisomal hydratase and acyl-CoA oxidase). The alterations in enzyme expression reflect an insulinomimetic effect in GSF and a thyromimetic effect in APF. Neoplasms resulting from APF show a more differentiated phenotype than those arising from GSF. We suggest that the different and in many aspects opposite effects of the 2 carcinogens on key enzymes of distinct pathways of energy metabolism modulate the process of neoplastic liver cell transformation and result in phenotypically different preneoplasias and neoplasias reflecting different cellular lineages.
Int J Cancer 1998 Jun 19
PMID:Differential expression of key enzymes of energy metabolism in preneoplastic and neoplastic rat liver lesions induced by N-nitrosomorpholine and dehydroepiandrosterone. 964 43

N-(4-Hydroxyphenyl)retinamide (4HPR) is currently used in cancer prevention and therapy trials. It is thought that its effects result from induction of apoptosis. 4HPR-induced apoptosis in human cervical carcinoma C33A cells involves enhanced generation of reactive oxygen species (ROS). In this study we explored the mechanism by which 4HPR increases ROS and induces apoptosis in these cells. 4HPR induced cytochrome c release from mitochondria to cytoplasm, activated caspase-3, and caused a membrane permeability transition (MPT). All these 4HPR's effects, as well as the induction of apoptosis, were inhibited by antioxidants, which decrease ROS. Thenoyltrifluoroacetone, a mitochondrial respiratory chain (MRC) complex II inhibitor, and carbonylcyanide m-chlorophenyl hydrazone, which uncouples electron transfer and ATP synthesis and inhibits ROS generation by MRC, inhibited 4HPR-induced ROS generation very effectively. Rotenone, an MRC complex I inhibitor was less effective and azide, an MRC complex IV inhibitor, exhibited a marginal effect. In contrast, antimycin A, an MRC complex III inhibitor, enhanced 4HPR-induced ROS generation. These findings suggest that 4HPR enhances ROS generation by affecting a target between complex II and complex III, presumably coenzyme Q. This effect is followed by release of cytochrome c, increased caspase-3 activity, induction of MPT and eventual DNA fragmentation and cell death.
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PMID:Implication of mitochondria-derived reactive oxygen species, cytochrome C and caspase-3 in N-(4-hydroxyphenyl)retinamide-induced apoptosis in cervical carcinoma cells. 1059 38

Tamoxifen (TAM) is used in the treatment of breast cancer and decreases the incidence of breast cancer when given to healthy women for different therapeutic purposes. This expansion of its use calls for further studies of its own potential side effects and those in combination with other prescription drugs. Diazepam (DP) is one such drug normally administered to patients who are under cancer treatment and those who suffer from insomnia. The present study examines the effect of individual and simultaneous administration of TAM and DP at therapeutic dose level of 0.8 mg/Kg/day of TAM and 0.3 mg/Kg/day of DP to normal female Wistar rats for a period of 12 weeks. The drugs were administered orally by mixing it in pellet made by wheat dough. There was no significant change in the terminal body weight and liver weights of animals. The ovary weights in TAM + DP treated animals were significantly decreased. The serum succinate dehydrogenase (SDH) levels were significantly lower in TAM, DP and TAM + DP treated rats and comparatively were lowest in TAM and TAM + DP treated animal groups. Serum glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT), acid and alkaline phosphatase (ACP & ALP) levels were significantly higher in the three treated groups, but comparatively lower in TAM + DP treated animals when compared to TAM or DP alone treated rats. There was marked increase in liver triglyceride and cholesterol levels in the three treated groups but remarkable decrease in liver glycogen. Total serum cholesterol levels were significantly high in DP and TAM + DP treated rats and total serum triglyceride levels were significantly high only in TAM treated rats. As a whole it can be concluded that DP does not enhance TAM toxicity on simultaneous administration, but on its own when administered individually brings about perturbation in lipid storage and metabolism.
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PMID:A toxicity study of simultaneous administration of Tamoxifen and Diazepam to female Wistar rats. 1066 14

Dietary restriction (DR) is the only known intervention that delays aging and age-related diseases. Mechanisms proposed to explain this DR effect include a decline in free radical production and an increase in free radical detoxification. In the present study the effect of bleomycin (BLM) as a reactive oxygen species-generating antitumor drug has been evaluated on antioxidant enzymes and the electron transport system in different cellular fractions of liver in female and male Fischer 344 rats. Animals were fed ad libitum (AL) or 60% of the AL intake (DR) and were given a single intraperitoneal injection of 2.5, 5, or 10 mg BLM/kg body wt. After four weeks, BLM significantly increased glutathione peroxidase and lactate dehydrogenase activities in liver cytosol of female AL rats and increased activity even more in male rats. Similar changes were also noted for glutathione reductase and glucose 6-phosphate dehydrogenase activities in BLM-treated AL rats. In liver mitochondria, glutathione peroxidase was increased in female and male AL rats but was increased more in female rats. Drug treatment had no significant effect on these enzyme activities in cytosolic or mitochondrial fractions of DR animals. Profound effects of BLM were noted in activities of complexes I, III, and IV of the electron transport system in AL and DR female and male rats; however, complex II demonstrated no significant diet or treatment effect. Induced antioxidant enzyme activities in BLM-treated AL rats may be a response to excessive free radical generation due to BLM metabolism in AL animals that is mitigated by DR. Furthermore, dysfunction of the electron transport system might suggest its role in a secondary generation of free radicals during BLM metabolism contributing to its toxicity.
Nutr Cancer 2000
PMID:Effects of bleomycin on liver antioxidant enzymes and the electron transport system from ad libitum-fed and dietary-restricted female and male Fischer 344 rats. 1079 15

The expression of ATP-binding cassette superfamily transporter genes, such as P-glycoprotein/multidrug resistance (MDR) 1 and MDR protein (MRP) 1, is often up-regulated in various tumor types and is involved in responses to some anticancer chemotherapeutic agents. Five human MRP subfamily members (MRP2-6) with structural similarities to MRP1 have been identified. The relationships between MRP2-6 mRNA levels and drug resistance are not well understood. Data on 45 patients with colorectal cancer were analyzed. Of the ATP-binding cassette superfamily genes, we asked whether mRNA levels of MDR1, MRP1, MRP2, and MRP3 correlated with drug resistance to anticancer agents. For this analysis, we used quantitative reverse transcription-PCR, and the sensitivity to anticancer agents in surgically resected colon carcinomas was determined using the in vitro succinate dehydrogenase inhibition test. MDR1, MRP1, and MRP3 were highly expressed in normal colorectal mucosa, and the relative mRNA levels of MDR1, MRP1, and MRP3 in cancerous tissues compared with noncancerous tissues were decreased or unchanged. By contrast, MRP2 mRNA expression was low in normal colorectal mucosa and specifically increased in cancer regions compared with noncancerous regions. Of the anticancer agents prescribed for patients with colorectal cancers, including doxorubicin, mitomycin C, cisplatin, 5-fluorouracil, etoposide, and a camptothecin derivative, mRNA expression of MRP2 was significantly associated with resistance to cisplatin. MRP2 may be important for resistance to cisplatin treatment in colorectal cancer.
Clin Cancer Res 2000 Jun
PMID:Increased expression of an ATP-binding cassette superfamily transporter, multidrug resistance protein 2, in human colorectal carcinomas. 1087 92

Most pheochromocytomas are sporadic but about 10% are though to be hereditary. Although the etiology of most inherited pheochromocytoma is well known, little is known about the etiology of the more common sporadic tumor. Recently, germ-line mutations of SDHD, a mitochondria complex II gene, were found in patients with hereditary paraganglioma. We sought to determine whether SDHD plays a role in the development of sporadic pheochromocytomas and performed a mutation and deletion analysis of SDHD. Among 18 samples, we identified 4 heterozygous sequence variants (3 germ-line, 1 somatic). One germ-line SDHD mutation IVS1+2T>G (absent among 78 control alleles) is predicted to cause aberrant splicing. On reinvestigation, this patient was found to have a tumor of the carotid body, which was likely a paraganglioma. Another patient with malignant, extra-adrenal pheochromocytoma was found to have germ-line c.34G> A (G12S). However, this sequence variant was also found in 1 of 78 control alleles. The third, germ-line nonsense mutation R38X was found in a patient with extra-adrenal pheochromocytoma. The only somatic heterozygous mutation, c.242C>T (P81L), has been found in the germ line of two families with hereditary paraganglioma and is conserved among four eukaryotic multicellular organisms. Hence, this mutation is most likely of functional significance too. Overall, loss of heterozygosity in at least one of the two markers flanking SDHD was found in 13 tumors (72%). All of the tumors that already harbored intragenic SDHD mutations, whether germ-line or somatic, also had loss of heterozygosity. Our results indicate that SDHD plays a role in the pathogenesis of pheochromocytoma. Given the minimum estimated germline SDHD mutation frequency of 11% (maximum estimate up to 17%) in this set of apparently sporadic pheochromocytoma cases and if these data can be replicated in other populations, our observations might suggest that all such patients be considered for SDHD mutation analysis.
Cancer Res 2000 Dec 15
PMID:Somatic and occult germ-line mutations in SDHD, a mitochondrial complex II gene, in nonfamilial pheochromocytoma. 1115 72

Electrochemotherapy is a novel cancer treatment in which electric pulses (EP) are used as a means of delivering anticancer agents to the cytoplasm of cancer cells (electroporation). The present study evaluates whether electrochemotherapy has in vitro and in vivo anticancer effects in murine bladder cancer. Using mouse bladder tumor cells (MBT-2 cells), in vitro electrochemotherapy was performed by applying EP to the cell suspension immediately after the addition of anticancer agents. The cytotoxicity of adriamycin (ADM), bleomycin (BLM) and cis-diamminedichloroplatinum(II) (CDDP) was determined by measuring succinate dehydrogenase (SD) activity in both electroporated and non-electroporated cells. In addition, intracellular concentrations of these anticancer agents were also measured. In the in vivo study, tumor-bearing C3H/He mice were treated with an intraperitoneal injection of anticancer agents followed by a local delivery of EP at the tumor site. Then, tumor growth rate (TGR) was determined and compared to that in the sham-treated control group, the EP-only group and the drug-only group. The in vitro study showed that, with electroporation, the cytotoxicity of BLM in electroporated cells was increased by as much as 95.7-fold compared to that of non-electroporated MBT-2 cells; CDDP showed only an increase of 1.8-fold and ADM showed no increase. After electroporation, the intracellular concentration of BLM, CDDP and ADM showed an increase of 120-, 1.7- and 0.8-fold, respectively. In electrochemotherapy for in vivo growing tumors, the potentiation of the antitumor effect was most prominent when combined with BLM, only slightly with CDDP, and totally absent with ADM. It is clear from in vitro and in vivo studies that, in a murine bladder tumor, the anticancer effect of BLM can be considerably potentiated by applying EP. Thus, BLM seems to be the most suitable anticancer agent for electrochemotherapy of bladder cancer.
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PMID:Potentiation of effects of anticancer agents by local electric pulses in murine bladder cancer. 1122 18

Hereditary paragangliomas or glomus tumors are usually benign slow-growing tumors in the head and neck region. The inheritance pattern of hereditary paraganglioma is autosomal dominant with imprinting. Recently, we have identified the SDHD gene encoding subunit D of the mitochondrial respiratory chain complex II as one of the genes involved in hereditary paragangliomas. Here, we demonstrate that two founder mutations, Asp92Tyr and Leu139Pro, are responsible for paragangliomas in 24 and 6 of the 32 independently ascertained Dutch paraganglioma families, respectively. These two mutations were also detected among 20 of 55 isolated patients. Ten of the isolated patients had multiple paragangliomas, and in eight of these SDHD germline mutations were found, indicating that multicentricity is a strong predictive factor for the hereditary nature of the disorder in isolated patients. In addition, we demonstrate that the maternally derived wild-type SDHD allele is lost in tumors from mutation-carrying patients, indicating that SDHD functions as a tumor suppressor gene.
Genes Chromosomes Cancer 2001 Jul
PMID:Nearly all hereditary paragangliomas in the Netherlands are caused by two founder mutations in the SDHD gene. 1139 98

Mithramycin (MTR) is an anti-cancer antibiotic that blocks the macromolecular biosynthesis via reversible interaction with DNA template in the presence of bivalent metal ion such as Mg2+. In absence of DNA, mithramycin forms two types of complexes with Mg2+, complex I (with 1:1 stoichiometry in terms of MTR: Mg2+) and complex II (with 1:2 stoichiometry in terms of MTR: Mg2+). In an eukaryotic system, the drug would interact with chromatin, a protein-DNA complex. We have employed the spectroscopic techniques such as absorption and fluorescence to study the interaction of MTR: Mg2+ complexes with rat liver chromatin. In this report, we have shown that the two types of ligands have different binding potentials with the same chromatin. This supports our proposition that complexes I and II, are different molecular species. We have also shown that the histone protein(s) reduce the binding potential and the number of available sites for both ligands.
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PMID:Interaction of mithramycin with chromatin. 1156 35


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