Peroxiredoxins (Prx's) are a superfamily of peroxidases that are ubiquitous in all super-kingdoms. Previous biochemical and structural studies have suggested that Prx's could be divided into five subfamilies (1-Cys, Typical 2-Cys, Atypical 2-Cys C-, L- and R- types). In this work, we have developed a set of regular expression patterns describing subfamily-specific spatial constraints of the key catalytic residues. Using these patterns, 1,016 Prx's available in public databases were classified into the five subfamilies. Our method performed well for most of the types except for Atypical 2 Cys R type.
Classification* ; Peroxidases ; Peroxiredoxins*

BACKGROUND: Peroxidases (Prx) of the peroxiredoxin family reduce hydrogen peroxide and alkyl hydroperoxides to water and alcohol respectively. Hydrogen peroxide is implicated as an intracellular messenger in various cellular responses such as proliferation and differentiation. And Prx I activity is regulated by Cdc-2 mediated phosphorylation. This work was undertaken to investigate the proliferation role of peroxiredoxin III as a member of Prx family in Prx III overexpressed HeLa cell line. METHODS: To provide further evidence of proliferation, we selected Prx III stably expressed HeLa Tet-off cell lines. Cell proliferation was examined by using proliferation reagent WST-1 in the presence or absence of doxycycline. Prx III, 2-cys Prx enzymes exist as homodimer. The activation of Prx III heterodimer with induced and endogenous Prx III was examined by immunoprecipitation. RESULTS: Immunoprecipitation analysis of the induced and endogenous Prx III with anti-myc showed that the induced wild type (WT) and dominant negative (DN) Prx III from HeLa Prx III Tet-off stable cell heterodimerized with endogenous Prx III each other. And the expression level of induced Prx III was examined after addition of doxycycline. By 72 hr, the expression level of induced Prx III was diminished gradually and the half-life of the induced wild type Prx III was approximately 17 hr. The proliferation experiment demonstrated that the relative proliferation value of induced and endogenous WT Prx III stable cell has no changes but the DN Prx III induced HeLa Tet-off stable cells were lower than endogenous Prx III. CONCLUSION: In conclusion, the HeLa dominant negative Prx III Tet-off stable cells were decreased the proliferation.
Cell Line ; Cell Proliferation ; Doxycycline ; Half-Life ; HeLa Cells* ; Humans* ; Hydrogen Peroxide ; Immunoprecipitation ; Peroxidases ; Peroxiredoxin III* ; Peroxiredoxins* ; Phosphorylation

OBJECTIVETo characterize the expressions of peroxiredoxin 1 (Prx1), peroxiredoxin 6 (Prx6) and glial fibrillary acidic protein (GFAP) in human brain astrocytoma and explore their clinical significance.

METHODSThe protein and mRNA expression levels of Prx1, Prx6 and GFAP in human brain astrocytoma and normal brain tissue specimens were determined by Western blotting, RT-PCR and immunohistochemistry.

RESULTSThe protein and mRNA expressions of Prx1 and Prx6 increased significantly in the order of normal brain tissue, grade II astrocytoma, grade III astrocytoma and grade IV astrocytoma (P<0.05). The protein and mRNA expressions of GFAP decreased significantly in grade III and IV astrocytoma compared with those in grade II astrocytoma and normal brain tissues (P<0.05).

CONCLUSIONPrx1 and Prx6 may play important roles in the invasion and malignant development of human brain astrocytoma, and may serve as biomarkers for evaluating the invasiveness, malignancy and prognosis of the tumor as well as potential molecular targets in astrocytoma therapy.

Adolescent ; Adult ; Aged ; Astrocytoma ; metabolism ; pathology ; Brain Neoplasms ; metabolism ; pathology ; Child ; Child, Preschool ; Female ; Glial Fibrillary Acidic Protein ; metabolism ; Humans ; Male ; Middle Aged ; Peroxiredoxin VI ; metabolism ; Peroxiredoxins ; metabolism ; Young Adult

OBJECTIVETo investigate the effects of Yiqi Chutan Recipe (YCR, a Chinese herbal prescription for invigorating qi and removing phlegm) on the growth and metastasis of tumor, survival time, and the expressions of peroxiredoxin (PRDX-1 and PRDX-6) in tumor tissue of C57BL/6J mice bearing Lewis lung carcinoma.

METHODSLewis lung carcinoma cells were transplanted to 90 C57BL/6J mice receiving preconditioning for inducing Pi-deficiency syndrome and divided into three groups treated respectively with saline, high dose YCR (3.0 g/kg) and low dose YCR (1.0 g/kg) once a day via gastric infusion. Besides, a group of 30 healthy mice simply received tumor cell transplantation was set up for controls. Ten mice selected from each group were sacrificed 21 days later, the size, weight and lung metastasis foci of tumor in mice were measured, and expressions of PRDX-1 and PRDX-6 in tumor tissue were detected using immunohistochemical method. The survival time of the remained 20 mice in each groups was observed.

RESULTSTumor size, weight and the numbers of lung metastatic foci were (1.14 +/- 0.30) cm3, (0.83 +/- 0.26) g, (6.20 +/- 2.53) foci in the high dose YCR treated group, which were significantly lower than those in the control group [(2.83 +/- 0.35) cm3, (2.08 +/- 0.28) g, and (8.60 +/- 1.84) foci] respectively, also lower than those in the saline treated group [(2.29 +/- 0.49) cm3, (1.67 +/- 0.33) g and (8.70 +/- 2.00) foci]. The median survival time in the three groups, in above order, were 29.00 +/- 0.89 days, 22.00 +/- 0.75 days and 21.00 +/- 0.53 days; the average survival time in them 29.60 +/- 0.53 days, 22.90 +/- 0.50 days and 20.95 +/- 0.44 days; the PRDX-1 expression were 0.15 +/- 0.03, 0.52 +/- 0.07 and 0.61 +/- 0.09; and the PRDX-6 expression were 0.12 +/- 0.02, 0.43 +/- 0.06 and 0.56 +/- 0.07, all showed significant difference in comparing the indices in the high dose treated group with those in the control group and in the saline treated group (P < 0.05 or P < 0.01). The tumor growth inhibition rate was 50.30% in the high dose YCR group with life prolongation rate of 41.29%, all better than those in the low dose YCR treated group (P < 0.05).

CONCLUSIONSYCR can remarkably inhibit the growth and metastasis of Lewis lung carcinoma in mice with Pi-asthenia syndrome, prolong their survival period, and its mechanism is possibly related to the reduction of over expressed PRDX-1 and PRDX-6.

Animals ; Carcinoma, Lewis Lung ; drug therapy ; metabolism ; pathology ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Lung Neoplasms ; drug therapy ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Peroxiredoxin VI ; metabolism ; Peroxiredoxins ; metabolism

Silicosis is one of the most serious occupational diseases in China and dates back to centuries ago. In this study, we successfully established a rat model of silicosis by intratracheal silica injection for 28 days and determined hydroxyproline levels to evaluate collagen metabolism in lung homogenates. Oxidative stress status was evaluated by detecting catalase and glutathione peroxidase activities. Expression levels of peroxiredoxins (Prx I and Prx VI) were detected by Western blotting. Pulmonary surfactant protein A (SP-A) levels in rat serum and lung tissue were analyzed by ELISA, and SP-A and Prx expression levels in lung tissues were detected by immunohistochemistry. The results suggest that Prx proteins may be involved in pulmonary fibrosis induced by silica. Downregulation of SP-A expression caused due to silica is an important factor in the occurrence and development of silicosis.
Animals ; Disease Models, Animal ; Humans ; Lung ; enzymology ; metabolism ; Male ; Oxidative Stress ; Peroxiredoxin VI ; genetics ; metabolism ; Peroxiredoxins ; genetics ; metabolism ; Pulmonary Surfactant-Associated Protein A ; genetics ; metabolism ; Rats ; Silicon Dioxide ; toxicity ; Silicosis ; genetics ; metabolism

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

OBJECTIVE: To assess the expression pattern of all six Prxs in normal ovarian tissue and epithelial ovarian tumor cell using immunohistochemical staining. METHODS: Patients were retrieved from those who had undertaken operation in Obstetrics and Gynecology of our hospital from January 1995 to June 2005. According to the pathologic result, five patients were allocated randomly in each group of malignant serous, malignant mucinous, benign serous and benign mucinous ovarian tumor. And another five with normal ovarian epithelial cell were included for the comparison. Immunohistochemical staining was performed with Prx I to VI antibodies. Using microscopy, we evaluated the immunoreactivities of nucleus and cytoplasm semiquantitatively by dividing into four categories : -; no immunoactivity present, +; weak, ++; moderate, +++; strong staining. RESULTS: The immunopositivity of Prx III in cytoplasm shows weak to moderate and Prx VI moderate to strong in normal ovarian tissue. In mucinous epithelial ovarian tumor cell, cytoplasmic Prx IV shows stronger activity than in normal epithelial cell or serous tumor cell. In malignant epithelial cell, Prx V shows stronger activity in cytoplasm than normal epithelial cell. It shows characteristically granular pattern. Prx VI shows stronger activity in the nucleus of malignant epithelial cell compared to normal epithelial cell or benign tumor epithelial cell. CONCLUSION: Normal ovarian tissue showed higher affinity for Prx III and VI. In epithelial ovarian tumor, cytosolic Prx IV in mucinous tumor, cytosolic Prx V and nuclear Prx VI in malignant tumor were overexpressed.
Antibodies ; Cytoplasm ; Cytosol ; Epithelial Cells ; Female ; Gynecology ; Humans ; Microscopy ; Mucins ; Obstetrics ; Ovary* ; Peroxiredoxins* ; Protein Isoforms*

PURPOSE: Peroxiredoxins(PRDXs) are antioxidant enzymes that play an important role on cell differentiation, proliferation and apoptosis. In this study, we investigated if the expression levels of PRDX I were related to bladder cancer. MATERIALS AND METHODS: The mRNA level of PRDX I was examined via real time polymerase chain reaction(PCR) in 186 cancer specimens from patients with primary bladder cancer, 73 corresponding samples of normal looking bladder mucosae surrounding the cancer and 21 samples of normal bladder mucosae. We investigated the correlation between the expression levels of PRDX I and the clinico-pathological parameters of the 154 patients who could be followed up more than three years. RESULTS: The expression levels of PRDX I in bladder cancer(0.73pg/ml) were significantly higher that that in the normal bladder mucosae (0.04 pg/ml)(p<0.01) or that in the corresponding normal bladder mucosae surrounding the cancer(0.38pg/ml)(p<0.01). The expression level of PRDX I was not significantly enhanced in the non-recurred(0.87pg/ml) superficial bladder tumor patients compared with the recurred superficial bladder tumor patients(0.63pg/ml), but it was significantly enhanced in the non-progressed(0.82pg/ml) patients compared with the progressed (0.50pg/ml) patients(p<0.05 for each). CONCLUSIONS: An enhanced expression of PRDX I is strongly associated with the development of bladder cancer. Moreover, enhanced expressions of PRDX I are also positively associated with a low rate of progression of bladder cancer, and this might be useful as a marker for assessing progression in human bladder cancers.
Apoptosis ; Cell Differentiation ; Humans ; Mucous Membrane ; Peroxiredoxins ; RNA, Messenger ; Urinary Bladder ; Urinary Bladder Neoplasms

Oxidative stress plays a critical role in the pathogenesis of asthma. To effectively control oxidative stress in asthmatics, it is important to investigate the precise intracellular mechanism by which the development of immunity, rather than immune tolerance and progression of airway inflammation, is induced. In this article, we suggest that protein tyrosine phosphatases, as intracellular negative regulators, and intracellular antioxidant enzymes such as peroxiredoxins can be regulated by oxidative stress during intracellular signaling.
Antioxidants ; Asthma ; Hypersensitivity ; Immune Tolerance ; Inflammation ; Oxidative Stress ; Peroxiredoxins ; Protein Tyrosine Phosphatases

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