Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04179 (MnSOD)
 2,777 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MnSOD is an antioxidant enzyme whose decrease in activity appears involved in tumorigenesis. We had previously reported the production of a monoclonal antibody, named 35.8, against rat MnSOD. In the present paper we show that it recognizes human and mouse MnSODs, although with different detection limits. We also use the antibody for immunofluorescence studies and observed that the antibody yields a positive staining of a non-nuclear protein, in rat and human organs where high concentration of MnSOD activity have been reported, and a lack of staining in rat kidney where MnSOD activity is decreased. Two tumors, an experimental rat hepatocarcinoma and a human liver metastasis from a gastrointestinal adenocarcinoma, are found negative for immunostaining.
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PMID:Monoclonal antibody 35.8 recognizes human, mouse and rat MnSODs in western blot and immunostaining. 808 Dec

Tirapazamine (TPZ, 3-amino-1,2,4-benzotriazine 1,4-di-N-oxide, SR 4233, WIN 59075) is a bioreductive antitumor agent with a high selective toxicity for hypoxic cells. The selective hypoxic toxicity of TPZ results from the rapid reoxidation of the one-electron reduction product, the TPZ radical, in the presence of molecular oxygen with the concomitant production of superoxide radical. Under hypoxia the TPZ radical kills cells by causing DNA double-strand breaks and chromosome aberrations. However, the mechanism of aerobic cytotoxicity is still a matter of debate. In this study, we investigated the mechanism of aerobic cytotoxicity by adapting human lung adenocarcinoma A549 cells to aerobic TPZ exposure and characterizing the changes associated with drug resistance. The adapted cells were resistant to aerobic TPZ exposures (with dose-modifying factors of up to 9.2), although hypoxic sensitivity was largely unchanged. Relative to the parental A549 cell line, adaptation to continuous aerobic TPZ exposure resulted in increased levels of manganese superoxide dismutase (up to 9.4-fold), moderate increases in glutathione reductase (up to 2.1-fold), and loss of both quinone oxidoreductase (DT-diaphorase) activity and NADPH cytochrome P450 reductase activity. There was essentially no change in the activity of the cytoplasmic form of superoxide dismutase (CuZnSOD), catalase, or glutathione peroxidase. The increased activity of antioxidant enzymes in the resistant cell lines (in particular MnSOD) strongly suggests that reactive oxygen species are, in large part, responsible for the toxicity of TPZ under aerobic conditions, and is consistent with aerobic and hypoxic drug cytotoxicity resulting from different mechanisms.
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PMID:Adaptation of human tumor cells to tirapazamine under aerobic conditions: implications of increased antioxidant enzyme activity to mechanism of aerobic cytotoxicity. 927 29

One reason why pancreatic cancer is so aggressive and unresponsive to treatments is its resistance to apoptosis. We report here that reactive oxygen species (ROS) are a prosurvival, antiapoptotic factor in pancreatic cancer cells. Human pancreatic adenocarcinoma MIA PaCa-2 and PANC-1 cells generated ROS, which was stimulated by growth factors (serum, insulin-like growth factor I, or fibroblast growth factor-2). Growth factors also stimulated membrane NAD(P)H oxidase activity in these cells. Both intracellular ROS and NAD(P)H oxidase activity were inhibited by antioxidants tiron and N-acetylcysteine and the inhibitor of flavoprotein-dependent oxidases, diphenylene iodonium, but not by inhibitors of various other ROS-generating enzymes. Using Rho(0) cells deficient in mitochondrial DNA, we showed that a nonmitochondrial NAD(P)H oxidase is a major source of growth factor-induced ROS in pancreatic cancer cells. Among proteins that have been implicated in NAD(P)H oxidase activity, MIA PaCa-2 and PANC-1 cells do not express the phagocytic gp91(phox) subunit but express several nonphagocytic oxidase (NOX) isoforms. Transfection with Nox4 antisense oligonucleotide inhibited NAD(P)H oxidase activity and ROS production in MIA PaCa-2 and PANC-1 cells. Inhibiting ROS with the antioxidants, Nox4 antisense, or MnSOD overexpression all stimulated apoptosis in pancreatic cancer cells as measured by internucleosomal DNA fragmentation, phosphatidylserine externalization, cytochrome c release, and effector caspase activation. The results show that growth factor-induced ROS produced by NAD(P)H oxidase (probably Nox4) protect pancreatic cancer cells from apoptosis. This mechanism may play an important role in pancreatic cancer resistance to treatment and thus represent a novel therapeutic target.
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PMID:Reactive oxygen species produced by NAD(P)H oxidase inhibit apoptosis in pancreatic cancer cells. 1515 19

Gastric cancer is the second most common cancer worldwide. The involvement of reactive oxygen species (ROS) in the pathogenesis of gastric malignancies is well known. Many human tumours have shown significant changes in the activity and expression of superoxide dismutase (SOD), which might be correlated with clinical-pathological parameters for the prognosis of human carcinoma. The aim of this study is the detection of MnSOD and CuZnSOD activity and their expression in gastric adenocarcinoma and healthy tissues. Gastric samples (adenocarcinoma and healthy tissues) harvested during endoscopy or resected during surgery were used to determine MnSOD and CuZnSOD activity and expression by spectrophotometric and Western blotting assays. The total SOD activity was significantly higher (p<0.05) in healthy mucosa with respect to gastric adenocarcinomas. No differences were found in MnSOD activity and, on the contrary, CuZnSOD activity was significantly lower (p<0.001) in cancer samples with respect to normal mucosa. The rate of MnSOD/CuZnSOD activity in adenocarcinoma was over ninefold higher than that registered in healthy tissues (p<0.05). Moreover, in adenocarcinoma MnSOD activity represented the 83% of total SOD with respect to healthy tissues where the ratio was 52% (p<0.001). On the contrary, in cancer tissues, CuZnSOD activity accounted for only 17% of the total SOD (p<0.001 if compared with the values recorded in normal mucosa). After immunoblotting, MnSOD was more expressed in adenocarcinoma with respect to normal mucosa (p<0.001), while CuZnSOD was similarly expressed in adenocarcinoma and healthy tissues. The SOD activity assay might provide a specific and sensitive method of analysis that allows the differentiation of healthy tissue from tumour tissue. The MnSOD to CuZnSOD activity ratio, and the ratio between these two isoforms and total SOD, presented in this preliminary study might be considered in the identification of cancerous from healthy control tissue.
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PMID:Superoxide dismutase in gastric adenocarcinoma: is it a clinical biomarker in the development of cancer? 1705 76

Human lung cancer is a major cause of cancer mortality worldwide. Advances in pathophysiologic understanding and novel biomarkers for diagnosis and treatment are significant tasks. We have undertaken a comprehensive glycoproteomic analysis of human lung adenocarcinoma tissues. Glycoproteins from paired lung adenocarcinoma and normal tissues were enriched by the lectins Con A, WGA, and AIL. 2-D PAGE revealed 30 differentially expressed protein spots, and 15 proteins were identified by MS/MS, including 8 up- (A1AT, ALDOA, ANXA1, CALR, ENOA, PDIA1, PSB1 and SODM) and 7 down-regulated (ANXA3, CAH2, FETUA, HBB, PRDX2, RAGE and VIME) proteins in lung cancer. By reverse-transcription PCR, nine proteins showed positive correlation between mRNA and glycoprotein expression. Vimentin and fetuin A (alpha(2)-HS-glycoprotein) were selected for further investigation. While for vimentin there was little correlation between total protein and mRNA abundance, expression of WGA-captured glycosylated vimentin protein was frequently decreased in cancer. Glycoarray analysis suggested that vimentins from normal and cancerous lung tissue differ in their contents of sialic acid and terminal GlcNAc. For fetuin A, both total protein and mRNA abundance showed concordant decrease in cancer. WGA- and AIL-binding glycosylated fetuin A was also consistently decreased in cancer. Glycoarray analysis suggested that high mannose glycan structures on fetuin A were only detectable in cancer but not normal tissue. The intriguing expression patterns of different isoforms of glycosylated vimentin and fetuin A in lung cancer illustrate the complexities and benefits of in-depth glycoproteomic analysis. In particular, the discovery of differentially glycosylated protein isoforms in lung adenocarcinoma may represent avenues towards new functional biomarkers for diagnosis, treatment guidance, and response monitoring.
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PMID:Glycoproteomic analysis of human lung adenocarcinomas using glycoarrays and tandem mass spectrometry: differential expression and glycosylation patterns of vimentin and fetuin A isoforms. 1941 61

Barrett's esophagus (BE) is a premalignant condition associated with the development of esophageal adenocarcinoma (EAC). Previous studies have implicated hydrophobic bile acids and gastric acid in BE and EAC pathogenesis. In this study, we tested the hypothesis that DNA damage, cytotoxicity and oxidative stress induced by bile acids and gastric acid can be attenuated by the cytoprotective, hydrophilic bile acid glycoursodeoxycholic acid (GUDCA). Non-dysplastic BE cells were exposed for 10 min to pH 4 and/or bile acid cocktail or to pH 4 and a modified cocktail consisting of a mixture of bile acids and GUDCA. DNA damage was evaluated by the comet assay; cell viability and proliferation were measured by trypan blue staining and the MTS assay; reactive oxygen species (ROS) were measured using hydroethidium staining; oxidative DNA/RNA damage was detected by immunostaining with antibody against 8-OH-dG; thiol levels were measured by 5-chloromethylfluorescein diacetate (CMFDA) staining; and the expression of antioxidant proteins was evaluated by western blotting. DNA damage and oxidative stress were significantly increased, while thiol levels were decreased in BE cells treated with pH 4 and bile acid cocktail compared with cells treated with pH 4 alone or untreated cells. Bile acids and low pH also significantly decreased cell proliferation. Expression of the antioxidant enzymes, MnSOD and CuZnSOD, was elevated in the cells treated with bile acids and low pH. When GUDCA was included in the medium, all these effects of pH 4 and bile acids were markedly reduced. In conclusion, treatment of BE cells with acidified medium and a bile acid cocktail at physiologically relevant concentrations induces DNA damage, cytotoxicity, and ROS. The cytoprotective bile acid, GUDCA, inhibits these deleterious effects by inhibiting oxidative stress.
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PMID:Protective effects of glycoursodeoxycholic acid in Barrett's esophagus cells. 1954 10

The loss of manganese superoxide dismutase function has been associated with increased incidence of Barrett's esophagus and esophageal adenocarcinoma. In previous studies, we have demonstrated that loss of MnSOD resulted in severe esophageal damage by both endogenous and exogenous bile. However, the alterative manner of MnSOD in esophageal epithelium is largely unknown. In this study, we investigated the expression and localization of MnSOD in response to the exposure to bile salts in an esophageal epithelial cell line. Het-1A cells were seeded at 5 x 10(5) and 10(7) and incubated with taurocholate, cholate, glycocholate, deoxycholate, and the mixture of these bile salts. Mitochondria and cytoplasma were separated, and the expression and localization of MnSOD was determined by Western blot and immunocytochemical assay. Proliferation rates were strongly inhibited in the groups with taurocholate and bile salts mixture at 4 h, with 0.367 +/- 0.042 and 0.396 +/- 0.046, respectively, compared to 0.684 +/- 0.054 in untreated groups (P < 0.05). An increased apoptotic rate compared to untreated group (3.65 +/- 0.59) were significantly increased in taurocholate group and in bile salts mixture group were 33.62 +/- 10.25 and 31.52 +/- 8.97 at 4 h, respectively (P < 0.05). The protein level of MnSOD in mitochondria was increased at 4 h, but with a decreased enzymatic activity after bile salts treatment. Cytoplasmic MnSOD was detected in the cells with bile salts treatment. Immunocytochemical staining demonstrated that esophageal epithelial cell underwent morphological alteration and MnSOD relocalization after bile salts treatment. This is the first study to demonstrate cellular cytosolic MnSOD expression and that this relocalization to the cytosol is a cause for decreased MnSOD enzymatic activity. This suggests that bile salts may contribute to the dysfunction of mitochondria, by enzymatically inhibiting of MnSOD localization and thus activation in the mitochondria.
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PMID:Colocalization of MnSOD expression in response to oxidative stress. 1962 44

The present study is the first to evaluate the expression and activity of MnSOD, Cu/ZnSOD and catalase in human gastric samples, since ROS play a significant role in the pathogenesis of different forms of malignancy inducing mutations and various diseases such as gastric cancer. Biopsies and surgical samples from 53 patients (male/female 22/31, mean age 56.5+/-15.8 years) consisted of 15 healthy, 12 autoimmune atrophic gastritis, 10 Helicobacter pylori (HP) infection, 8 HP-negative chronic gastritis (CG) and 8 adenocarcinoma cases. Enzyme activity and expression were evaluated by spectrophotometry and immunoblotting after specific extraction in phosphate buffer. We found that MnSOD activity was increased in adenocarcinoma, CG and HP tissues (p<0.05-0.001), while Cu/ZnSOD was significantly lower in adenocarcinoma and HP tissues (p<0.001) when compared to the healthy control. MnSOD and Cu/ZnSOD were expressed to a significantly higher degree in adenocarcinoma and HP tissues (p<0.05 and <0.001 respectively) and to a significantly lower degree in CG tissues with respect to the healthy patients (p<0.05 and <0.001). A significant decrease in CAT activity in adenocarcinoma and HP tissues was observed (p<0.01 and <0.05). Gastric human neoplasms showed significant changes in antioxidant enzymes, that represent the first line in antioxidant protection against radical attack. The difficulties in correlating the antioxidant enzyme with the neoplasms was related to the complexity of the biochemical pathways that regulate the cellular redox balance. Our results are important in enhancing the understanding of the role that these enzymes play in the promotion/suppression of the carcinogenesis cascade in human gastric mucosa.
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PMID:Implications of antioxidant enzymes in human gastric neoplasms. 1978 4

Black raspberry extracts (RSE) have been shown to inhibit cancer cell growth and stimulate apoptosis. Also, studies have demonstrated that RSE inhibits transcriptional regulators including NFkappa B. Accordingly, we investigated the effect of RSE in inhibiting radiation (IR) induced NFkappa B mediated radioprotection in breast adenocarcinoma cells. MCF-7 cells were exposed to IR (2Gy), treated with RSE (0.5, 1.0, 2.0 micro g/ml) or treated with RSE (1.0 micro g/ml) followed by IR exposure, and harvested after 1, 3, 6, 24, 48, and 72 h. NFkappa B DNA-binding activity was measured by EMSA and phosphorylated Ikappa Balpha by immunoblotting. Expression of IAP1, IAP2, XIAP and survivin were measured by QPCR and immunoblotting. Cell survival was measured using MTT assay and cell death using Caspase-3/7 activity. Effect of RSE on IR induced MnSOD, TNFalpha, IL-1alpha and MnSOD activity was also determined. RSE inhibited NFkappa B activity in a dose-dependent manner. Also, RSE inhibited IR-induced sustained activation of NFkappa B, and NFkappa B regulated IAP1, IAP2, XIAP, and survivin. In addition, RSE inhibited IR-induced TNFalpha, IL-1alpha, and MnSOD levels and MnSOD activity. RSE suppressed cell survival and enhanced cell death. These results suggest that RSE may act as a potent radiosensitizer by overcoming the effects of NFkappa B mediated radioprotection in human breast cancer cells.
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PMID:Effect of black raspberry extract in inhibiting NFkappa B dependent radioprotection in human breast cancer cells. 2004 64

CuZnSOD and MnSOD have been shown to exert tumour suppressive activities; however, their exact molecular mechanism is still unclear. We investigated the molecular mechanism underlying the tumour suppressive activities of CuZnSOD and MnSOD using multicellular tumour spheroid (MTS), an in vitro tumour model. Overexpression of CuZnSOD and MnSOD significantly suppressed the growth of A549 and MCF-7 MTS, supporting a critical role(s) of reactive oxygen species (ROS) in tumour growth. In solid tumours, ROS is produced by metabolic stress due to insufficient oxygen and glucose supply and induces necrosis that is known to promote tumour progression by releasing the proinflammatory cytokine HMGB1. We observed that CuZnSOD and MnSOD overexpression prevents metabolic stress-induced necrosis and HMGB1 release by inhibiting mitochondrial ROS and intracellular O2- production in response to glucose depletion in two dimensional cell culture. CuZnSOD and MnSOD overexpression also significantly repressed the occurrence of necrosis that was observed during MTS culture. In human tumour tissues including lung pulmonary adenocarcinoma, CuZnSOD and MnSOD expression was detected in the para-necrotic region that was identified by the expression of a hypoxic marker carbonic anhydrase (CA) IX. These results suggest that CuZnSOD and MnSOD may suppress tumour growth through inhibiting metabolic stress-induced necrosis and HMGB1 release via inhibiting metabolic stress-induced mitochondrial ROS production.
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PMID:CuZnSOD and MnSOD inhibit metabolic stress-induced necrosis and multicellular tumour spheroid growth. 2051 11


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