Redox regulation by SOD2 modulates colorectal cancer tumorigenesis through AMPK-mediated energy metabolism.

Colorectal cancer (CRC) is a common malignancy. Many reports have implicated aberrant mitochondrial activity in the progression of CRC, with particular emphasis on the dysregulation of redox signaling and oxidative stress. In this study, we focused on manganese superoxide dismutase (MnSOD/SOD2), a key antioxidant enzyme, which maintains intracellular redox homeostasis. Current literature presents conflicting mechanisms for how SOD2 influences tumorigenesis and tumor progression. Here, we explored the role of SOD2 in CRC specifically. We found high levels of SOD2 expression in CRC tissues. We carried out a series of experiments to determine whether knockdown of SOD2 expression in CRC cell lines would reverse features of tumorigenesis. We found that reduced SOD2 expression decreased cell proliferation, migration, and invasion activity in CRC cells. Results from an additional series of experiments on mitochondrial function implicated a dual role for SOD2 in promoting CRC progression. First, proper level of SOD2 helped CRC cells maintain mitochondrial function by disposal of superoxide (O2.- ). Second, over-expression of SOD2 induced H2 O2 -mediated tumorigenesis by upregulating AMPK and glycolysis. Our results indicate that SOD2 may promote the occurrence and development of CRC by regulating the energy metabolism mediated by AMPK signaling pathways.

Mn-SOD Upregulation by Electroacupuncture Attenuates Ischemic Oxidative Damage via CB1R-Mediated STAT3 Phosphorylation.

Electroacupuncture (EA) pretreatment elicits the neuroprotective effect against cerebral ischemic injury through cannabinoid receptor type 1 receptor (CB1R). In current study, we aimed to investigate whether the signal transducer and activator of transcription 3 (STAT3) and manganese superoxide dismutase (Mn-SOD) were involved in the antioxidant effect of EA pretreatment through CB1R. At 2 h after EA pretreatment, focal cerebral ischemic injury was induced by transient middle cerebral artery occlusion for 60 min in C57BL/6 mice. The expression of Mn-SOD in the penumbra was assessed by Western blot and immunoflourescent staining at 2 h after reperfusion. In the presence or absence of Mn-SOD small interfering RNA (siRNA), the neurological deficit score, the infarct volume, the terminal deoxynucleotidyl transferase-mediated dUDP-biotin nick end labeling (TUNEL) staining, and oxidative stress were evaluated. Furthermore, the Mn-SOD protein expression and phosphorylation of STAT3 at Y705 were also determined in the presence and absence of CB1R antagonists (AM251, SR141716) and CB1R agonists (arachidonyl-2-chloroethylamide (ACEA), WIN 55,212-2). EA pretreatment upregulated the Mn-SOD protein expression and Mn-SOD-positive neuronal cells at 2 h after reperfusion. EA pretreatment also attenuated oxidative stress, inhibited cellular apoptosis, and induced neuroprotection against ischemic damage, whereas these beneficial effects of EA pretreatment were reversed by knockdown of Mn-SOD. Mn-SOD upregulation and STAT3 phosphorylation by EA pretreatment were abolished by two CB1R antagonists, while pretreatment with two CB1R agonists increased the expression of Mn-SOD and phosphorylation level of STAT3. Mn-SOD upregulation by EA attenuates ischemic oxidative damage through CB1R-mediated STAT3 phosphorylation in stroke mice, which may represent one new mechanism of EA pretreatment-induced neuroprotection against cerebral ischemia.

Effects of Manganese Superoxide Dismutase 9 Ala/Val Genetic Polymorphisms on Coronary Heart Disease / 现代检验医学杂志

Objective To study associations between manganese superoxide dismutase 9 Ala/Val (Mn-SOD 9 Ala/Val)genet-ic polymorphism and total superoxide dismutase (T-SOD)and Mn-SOD activity and the impact on coronary heart disease (CHD)were studied.Methods There were 82 CHD patients and 57 controls in this research.Sequencer was used to identify the genotype of Mn-SOD 9 Ala/Val genetic polymorphism and colorimeter was used to detect the serum T-SOD and Mn-SOD activity.Results Compared with the control group,the serum T-SOD and Mn-SOD activity of the CHD group was significantly reduced(t=4.83,6.57,P all<0.05),while the VV genotype and V allele of Mn-SOD 9 Ala/Val genetic poly-morphism of the CHD group were higher (χ2 =4.75,P <0.05).The serum T-SOD and Mn-SOD activity of the Mn-SOD 9 VV genotype was significantly lower than the Mn-SOD 9 AA genotype(t=2.96,3.11,P all<0.05).Conclusion The ser-um T-SOD and Mn-SOD activity in the CHD patients was reduced.Mn-SOD 9 Ala/Val genetic polymorphism was involved in the pathogenesis of CHD by influencing the Mn-SOD activity.

Mitochondrial antioxidant defence in radio-resistant Lepidopteran insect cells.

Cells isolated from Lepidopteran insects (butterfly and moths) display very high radioresistance as compared to mammals and other insect species. Since free radical induced mitochondrial damage under stress conditions is very crucial for cellular fate determination, antioxidant system is the major protective modality required to minimize stress-induced damage and to modulate cellular sensitivity. In this study, we predict the mitochondrial localization potential and co-existence of important antioxidant enzymes in insect cells and compare with other radiosensitive (mammals, Dipteran insects) and radioresistant (nematodes) species. Our study clearly demonstrates the inter-species variation in then localization potential of various antioxidant enzymes. A higher mitochondrial localization potential as a function of mitoprot score was evident for all important antioxidant enzymes in the lepidopteran insect Bombyx mori (Mn-SOD, 0.694; GPx, 0.862; TRPx, 0.997; TR, 0.9), besides an unusual mitochondrial localization prediction for catalase (0.453). We further found coexistence of glutathione and thioredoxin system in the mitochondria of lepidopteran insects as also reported in various plant species. On the basis of above observations, we hypothesize that a strong mitochondrial antioxidant enzyme system including the unusual coexistence of catalase, glutathione and thioredoxin system may help minimize the free radical mediated damage to mitochondria and can contribute to the intrinsic radioresistance of lepidopteran insects.

Extracellular superoxide dismutase, a potential extracellular biomarker candidate for prolactinoma / Superóxido dismutasa extracelular - candidato potencial a biomarcador extracelular del prolactinoma

AIM: To investigate whether the extracellular superoxide dismutase (EC-SOD) and manganese super-oxide dismutase (Mn-SOD) level changes during prolactinoma (PRL) development. METHODS: Surgical tissues from 37 female patients with PRL were tested for Mn-SOD and serum samples from such PRL patients were tested for EC-SOD level changes with Western Blot. The Mn-SOD level from blood cells was also investigated to show whether the Mn-SOD variation could locate tumorigenesis tissues. RESULTS: According to the patients' age analysis, age 20-40 years is high risk for getting PRL. There is a positive relationship between the PRL severity and EC-SOD. The Mn-SOD level from surgical tissues, but not blood cells, also shows a corresponding positive relationship to PRL severity, which indicates that elevated Mn-SOD might only happen in PRL tumorigenesis tissues. CONCLUSIONS: Extracellular superoxide dismutase is an extracellular protein and the serum EC-SOD could be a good candidate for the diagnoses of prolactinoma.

OBJETIVO: Investigar los cambios de niveles del superóxido dismutasa extracelular (EC-SOD) y el superóxido dismutasa de manganeso (Mn-SOD) durante el desarrollo del prolactinoma (PRL). MÉTODOS: Los tejidos quirúrgicos de 37 pacientes hembras con PRL fueron examinados para investigar los niveles de cambio de Mn-SOD, mediante la técnica de Western Blot. El nivel de Mn-SOD de las células sanguíneas fue investigado para ver si la variación de Mn-SOD puede indicar la localización de tejidos de tumorigénesis. RESULTADOS: Según el análisis de la edad de los pacientes, la edad de 20-40 años presenta un alto riesgo de desarrollar PRL. Hay una relación positiva entre la severidad del PRL y el EC-SOD. El nivel de Mn-SOD en los tejidos quirúrgicos - a diferencia de lo que ocurre en las células sanguíneas - muestra una relación positiva con respecto a la severidad del PRL, lo cual indica que un Mn-SOD elevado, sólo podría tener lugar en los tejidos de la tumorigénesis del PRL. CONCLUSIONES: El superóxido dismutasa extracelular (EC-SOD) es una proteína extracelular, y el EC-SOD sérico podría ser un buen candidato para diagnosticar el prolactinoma.

Screening of differential expression proteins from human oral lichen planus and normal oral mucosa by two-dimensional difference gel electrophoresis and mass spectrometry / 实用口腔医学杂志

Objective:To find biomarkers for oral lichen planus by comparing differential expressing proteins. Methods:10 cases of oral lichen planus and normal oral mucosa tissues were collected.Total protein was extracted; differential proteome profiles were established and analyzed by two-dimensional polyacrylamide gel electrophoresis(2D-PAGE) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Results:(1)The well-resolved,reproducible 2-DE patterns of oral lichen planus and normal oral mucosa were obtained. The results showed that average protein spots were 1 576?67 and 1 608?73 in oral lichen planus and normal oral mucosa respectively, (2) The 13 differential protein spots were identified by Imaging Master 2D image analysis software between oral lichen planus and normal oral mucosa. There were 7 protein spots in oral lichen planus were higher than those in normal oral mucosa, 6 protein spots in oral lichen planus were lower than those in normal oral mucosa. 10 differential expressing proteins were analyzed by mass spectrometry and bioinformation. 4 of them were well characterized including manganese superoxide dismutase (Mn-SOD), Annexin I, vimentin and unknown proteins. Conclusion:Differential expression proteins might be candidate biomarkers for diagnosis of oral lichen planus;and proteomic technique is valuable for screening the diagnostic biomarkers.