Peroxiredoxins (Prxs) are antioxidant enzymes that protect cells from oxidative stress by reducing intracellular accumulation of reactive oxygen species (ROS). In mammalian cells, the six Prx isoforms are ubiquitously expressed in diverse intracellular locations. They are involved in the regulation of various physiological processes including cell growth, differentiation, apoptosis, immune response and metabolism as well as intracellular ROS homeostasis. Although there are increasing evidences that Prxs are involved in carcinogenesis of many cancers, their role in cancer is controversial. The ROS levels in cancer cells are increased compared to normal cells, thus promoting cancer development. Nevertheless, for various cancer types, an overexpression of Prxs has been found to be associated with poor patient prognosis, and an increasing number of studies have reported that tumorigenesis is either facilitated or inhibited by regulation of cancer-associated signaling pathways. This review summarizes Prx isoforms and their basic functions, the relationship between the expression level and the physiological role of Prxs in cancer cells, and their roles in regulating cancer-associated signaling pathways.
Apoptosis ; Carcinogenesis ; Homeostasis ; Humans ; Metabolism ; Oxidative Stress ; Peroxiredoxins ; Physiological Processes ; Prognosis ; Protein Isoforms ; Reactive Oxygen Species

OBJECTIVE: To explore the relationship between peroxiredoxin I expression and seminal reactive oxygen species (ROS) in patients with idiopathic asthenozoospermia. METHODS: Twenty-six infertile male patients were selected from the Reproductive Medical Center, Xiangya Hospital, from September to December in 2012. Fresh semen was collected from an experimental group (26 idiopathic asthenozoospermia patients) and a control group (15 men with fertility history and normal semen). Luminol chemiluminescence method was applied to detect the seminal ROS level. Western blot was used to detect the peroxiredoxin I expression. RESULTS: 1)The seminal ROS level in the experimental group was significantly increased compared with that in the control group (P<0.05), and the seminal ROS level was negatively correlated with mobility of the sperm (r=-0.777, P<0.01). 2) Compared with the control group, the peroxiredoxin I expression was significantly downregulated in the experimental group (P<0.05). The content of sperm peroxiredoxin I in the 2 groups was negatively correlated with the seminal ROS level (r=-0.474, P<0.01). 3) The content of peroxiredoxin I had a positive correlation with human sperm motility(r=0.779, P<0.01). CONCLUSION The decline of peroxiredoxin I expression may be one of the crucial factors that leads to idiopathic asthenozoospermia. High level of ROS may be one of the main reasons for sperm vitality decline in patients with idiopathic asthenozoospermia.
Asthenozoospermia ; Case-Control Studies ; Humans ; Male ; Peroxiredoxins ; metabolism ; Reactive Oxygen Species ; chemistry ; Semen ; chemistry ; Sperm Motility ; Spermatozoa ; metabolism

OBJECTIVEThe aim of this study was to observe the effects of dioscin on apoptosis and on expression of PRDX1 in pancreatic cancer MiaPaCa-2 cells in vitro.

METHODSMTT assay was used to detect the growth rate among the medication groups treated with different concentrations of dioscin. The apoptosis rate was determined by annexin V-fluorescein isothiocyanate/propidium iodide double staining and flow cytometry. Western blot analysis was used to assay the expression of PRDX1 and apoptotic proteins in the cells. Reactive oxygen species (ROS) formation was measured by 2'7'-dichlorofluorescein diacetate (DCFH-DA).

RESULTSDioscin considerably inhibited the proliferation of MiaPaCa-2 cells in vitro. The inhibitory action was enhanced in a dose-dependent manner. The levels of intracellular ROS detected with DCFH-DA were highly increased after dioscin treatment. The flow cytometry analysis using annexin V-PI staining showed that compared with the apoptotic rate of control group [(3.5 ± 0.7)%], 2.5 µmol/L and 5 µmol/L dioscin induced apoptosis in (28.4 ± 0.9)% and (49.6 ± 2.7)% MiaPaCa-2 cells, and Western blot analysis showed that apoptotic proteins Bax and cleaved caspase-3 expressions were increased and antiapoptotic protein Bcl-2 expression was decreased. In addition, these effects could be blocked by antioxidant N-acetylcysteine (NAC) administration, and the apoptotic rates decreased to (10.8 ± 2.3)% and (18.8 ± 3.0)%, respectively. We further observed the decrease of PRDX1 expression after dioscin treatment. Moreover, after PRDX1 overexpression, dioscin treatment no longer induced high levels of ROS and apoptosis, and the apoptotic rate was decreased to (21.3 ± 5.9)%.

CONCLUSIONDioscin can down-regulate the PRDX1 expression, and then induces ROS-mediated apoptosis in cancer cells.

Apoptosis ; drug effects ; Diosgenin ; analogs & derivatives ; pharmacology ; Humans ; Pancreatic Neoplasms ; pathology ; Peroxiredoxins ; drug effects ; Reactive Oxygen Species ; metabolism

Alzheimer's disease (AD) pathogenesis is characterized by senile plaques in the brain and evidence of oxidative damage. Oxidative stress may precede plaque formation in AD; however, the link between oxidative damage and plaque formation remains unknown. Presenilins are transmembrane proteins in which mutations lead to accelerated plaque formation and early-onset familial Alzheimer's disease. Presenilins physically interact with two antioxidant enzymes thiol-specific antioxidant (TSA) and proliferation-associated gene (PAG) of the peroxiredoxin family. The functional consequences of these interactions are unclear. In the current study we expressed a presenilin transgene in Drosophila wing and sensory organ precursors of the fly. This caused phenotypes typical of Notch signaling loss-of-function mutations. We found that while expression of TSA or PAG alone produced no phenotype, co-expression of TSA and PAG with presenilin led to an enhanced Notch loss-of-function phenotype. This phenotype was more severe and more penetrant than that caused by the expression of Psn alone. In order to determine whether these phenotypes were indeed affecting Notch signaling, this experiment was performed in a genetic background carrying an activated Notch (Abruptex) allele. The phenotypes were almost completely rescued by this activated Notch allele. These results link peroxiredoxins with the in vivo function of Presenilin, which ultimately connects two key pathogenetic mechanisms in AD, namely, antioxidant activity and plaque formation, and raises the possibility of a role for peroxiredoxin family members in Alzheimer's pathogenesis.
Amino Acid Sequence ; Animals ; Drosophila ; metabolism ; physiology ; Drosophila Proteins ; metabolism ; Molecular Sequence Data ; Peroxiredoxins ; chemistry ; genetics ; metabolism ; Presenilins ; chemistry ; metabolism ; Receptors, Notch ; metabolism ; Sequence Alignment ; Signal Transduction

BACKGROUND/AIMS: Peroxiredoxin (Prx) belongs to a ubiquitous family of antioxidant enzymes that regulates many cellular processes through intracellular oxidative signal transduction pathways. Silica-induced lung damage involves reactive oxygen species (ROS) that trigger subsequent toxic effects and inflammatory responses in alveolar epithelial cells resulting in fibrosis. Therefore, we investigated the role of Prx in the development of lung oxidant injury caused by silicosis, and determined the implication of ROS in that process. METHODS: Lung epithelial cell lines A549 and WI26 were treated with 1% silica for 0, 24, or 48 hours, following pretreatment of the A549 cells with N-acetyl-L-cysteine and diphenylene iodonium and no pretreatment of the WI26 cells. We transfected an HA-ubiquitin construct into the A549 cell line and then analyzed the cells via Western blotting and co-immunoprecipitation. RESULTS: Silica treatment induced cell death in the A549 lung epithelial cell line and selectively degraded Prx I without impairing protein synthesis in the A549 cells, even when the ROS effect was blocked chemically by N-acetyl-L-cysteine. A co-immunoprecipitation study revealed that Prx I did not undergo ubiquitination. CONCLUSIONS: Silica treatment induces a decrease of Prx I expression in lung epithelial cell lines regardless of the presence of ROS. The silica-induced degradation of Prx does not involve the ubiquitin-proteasomal pathway.
Cell Line ; Epithelial Cells/drug effects/metabolism ; Humans ; Lung/chemistry/*drug effects/metabolism ; Peroxiredoxins/analysis/*physiology ; Protein Isoforms ; Reactive Oxygen Species/metabolism ; Silicon Dioxide/*toxicity ; Ubiquitin/metabolism

OBJECTIVETo evaluate the mRNA and protein expressions of peroxiredoxin II (PrxII) in hepatocellular carcinoma (HCC) and their significance.

METHODSHCC was induced by aflatoxin B1 (AFB1) in 6 tree shrews (Tupaia belangeri chinensis). The expression levels of PrxII mRNA and protein were detected by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot on HCC tissues and on their surrounding liver tissues (para-HCC). Biopsied liver tissues were taken before the HCC induction (pre-HCC) from the same animals and from a group of blank controlled animals that served as controls. Liver biopsy specimens from 18 cases of human HCC and from 17 healthy human volunteers were studied using the same methods.

RESULTSThe mRNA and protein expressions of PrxII in tree shrew HCC tissues were significantly higher than those in para-HCC and pre-HCC tissues, and also higher than those in the liver tissues from the control animals (all P < 0.05). The expression levels of PrxII mRNA and protein in human HCC tissues were also significantly higher than those in their para-HCC tissues and in the human normal liver tissues (P < 0.05).

CONCLUSIONPrxII might play an important role in hepatocarcinogenesis and might be used as a molecular target for HCC prevention and treatment.

Adult ; Aged ; Animals ; Carcinoma, Hepatocellular ; metabolism ; pathology ; Female ; Humans ; Liver ; metabolism ; pathology ; Liver Neoplasms ; metabolism ; pathology ; Liver Neoplasms, Experimental ; metabolism ; pathology ; Male ; Middle Aged ; Peroxiredoxins ; genetics ; Tupaiidae

OBJECTIVETo provide evidence for illustrating the molecular mechanism of nickel carcinogenesis, and to identify the differential expression of protein in crystalline NiS-induced neoplastic transformation of human bronchial epithelial cell by proteomics technology.

METHODSTwo dimensional electrophoresis (2-DE) and the ImageMaster 3.10 software were used to analyze the differential expression of protein, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) combined with database search was applied to identify protein peroxiredoxin 2 (PDX2) related to malignant transformation.

RESULTSThe good 2-DE pattern including resolution and reproducibility was obtained. Nearly 700 expressed proteins per 2-D gel were isolated with molecular weights (MW) ranging from 14,400 to 94,000 KD and pI 3 - 10. A protein PDX2 with MW 21,890 KD, pI 5.66, which was highly expressed in malignantly transformed cell, was identified using MALDI-TOF-MS.

CONCLUSIONPDX2 was involved in malignant transformation of human bronchial epithelial cell induced by crystalline nickel sulfide.

Bronchi ; cytology ; Cell Line ; Cell Transformation, Neoplastic ; chemically induced ; metabolism ; Epithelial Cells ; cytology ; drug effects ; metabolism ; Humans ; Nickel ; toxicity ; Peroxiredoxins ; metabolism ; Proteome

To construct the eukaryotic expression plasmid of human PRX3 and measure its expression in the HEK-293FT cells, the full-length coding region of human PRX3 was cloned by PCR and inserted into the eukaryotic expression vector pcDNA4-Xpress (A). HEK-293FT cells were transiently transfected with the recombinant plasmid. Western blot and immuofluorescence were used to detect the expression of the fusion protein. In the experiment, restriction analysis identified the construction of the recombinant plasmid and the inserted sequence was identical with that published on GenBank. Western blot and immunofluorescence confirmed the expression of the recombinant protein in transfected HEK-293FT cells. It was concluded that the eukaryotic expression plasmid of human PRX3 was constructed successfully and the recombinant could be expressed efficiently in HEK-293FT cells, which provides a sound basis for the further study on human PRX3.
Cell Line, Transformed ; Cloning, Molecular ; Embryo, Mammalian ; Eukaryotic Cells ; metabolism ; Gene Expression ; Genetic Vectors ; Humans ; Kidney ; cytology ; metabolism ; Peroxidases ; biosynthesis ; genetics ; Peroxiredoxin III ; Peroxiredoxins ; Plasmids ; genetics ; Transfection

PURPOSE: Apoptosis is known to be induced either by direct oxidative damage from oxygen free radicals or hydrogen peroxide, or from their generation in cells by injurious agents. Peroxiredoxin plays an important role in eliminating peroxides generated during metabolism. The aim of this study is to elucidate the role of Prx (peroxiredoxin) enzymes during the cellular response to oxidative stress. METHODS: The presence of Prx isoforms was demonstrated by immunoblot analysis using Prx isoforms-specific antibodies, and RT-PCR using Prx isozyme coding sequences. Annexin V-FITO apoptosis detection method was used to measure the cell death following exposure to H2O2. RESULTS: Treatment of MCF7 cell lines with H2O2 resulted in the dose-dependent expression of Prx I and II. Observed decreases in the mRNA expressions of Prx I and II, analyzed by RT-PCR, correlated well with the results of immunoblot analysis. The treatment of normal breast cell line, MCF10A, with H2O2 resulted in rapid cell death, while the breast cancer cell line, MCF7, was resistant. In addition, we confirmed that Prx I and II transfected MCF10A cells were more prone to cell death than MCF10A transfected with vector alone, after H2O2 treatment. CONCLUSION: These findings suggest that Prx I and II have an important function as inhibitors of cell death during the cellular response to oxidative stress.
Antibodies ; Apoptosis* ; Breast ; Breast Neoplasms ; Cell Death ; Cell Line ; Clinical Coding ; Free Radicals ; Hydrogen Peroxide ; MCF-7 Cells* ; Metabolism ; Oxidative Stress ; Oxygen ; Peroxides ; Peroxiredoxins ; Protein Isoforms ; RNA, Messenger

OBJECTIVETo evaluate the change in protein expression of peroxiredoxin I (Prx I) during pulmonary fibrosis among rats exposed to silica dust and to investigate the role of Prx I in pulmonary fibrosis.

METHODSNinety male Wistar rats were randomly divided into control group (n = 60) and experimental group (n = 30). The control group received intratracheal perfusion of saline (1 ml), while the experimental group received intratracheal perfusion of suspension of silica dust (50 mg/ml) to establish a rat model of silicosis. At 1, 2, 3, 4, 6, or 8 weeks after treatment, 10 rats in control group and 5 rats in experimental group were sacrificed. The lung tissues were collected for conventional pathological observation. The protein expression of Prx I at each time point was measured by immunohistochemistry and Western blot.

RESULTSAmong the rats exposed to silica dust, Prx I was seen in the form of brown particles that were mainly distributed in the alveolar septa and the cytoplasm of alveolar epithelial cells, macrophages, vascular endothelial cells, and smooth muscle cells around the blood vessels and tracheae. The control group showed weak protein expression of Prx I, and the experimental group had significantly higher protein expression of Prx I than the control group at all time points (P < 0.05). In the experimental group, the protein expression of Prx I was upregulated significantly at 1 and 2 weeks and decreased at 3∼8 weeks.

CONCLUSIONThe change in protein expression of Prx I may be one of the important causes of the onset and development of pulmonary fibrosis in rats exposed to free silica.

Animals ; Disease Models, Animal ; Lung ; enzymology ; pathology ; Male ; Peroxiredoxins ; metabolism ; Pulmonary Fibrosis ; enzymology ; pathology ; Rats ; Rats, Wistar ; Silicon Dioxide ; toxicity ; Silicosis ; enzymology ; pathology