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*

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*

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

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

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

BACKGROUND: Peroxiredoxin I (Prx I) is part of an oxidative stress defense system with thioredoxin peroxidase activity to eliminate hydrogen peroxide (H2O2). UV irradiation is one of the major sources to produce H2O2, which should then be scavenged by antioxidant systems to maintain functional integrity of the skin. OBJECTIVE: This study aimed to evaluate the modulation of Prx I by ultraviolet B (UVB) irradiation in human epidermal keratinocytes. The modulation of Prx I expression by H2O2 was also evaluated. METHOD: Primary culture of epidermal keratinocytes was performed, and sub-confluent cells were irradiated with UVB irradiation (20mJ/cm(2)). Western blot and Northern blot analysis were performed after the cells were harvested at different time-points after UVB irradiation. Prx I expression and intracellular levels of H2O2 were evaluated in the cells which had been irradiated with different doses of UVB. The localization of Prx I expression was identified by immunocytochemical staining. RESULTS: UVB irradiation induced Prx I mRNA and protein expressions from 3 h and 6 h after irradiation, respectively, indicating that UVB induced Prx I expression at a transcription level. Intracellular H2O2 levels were steadily increased as keratinocytes were irradiated with increasing doses of UVB. Next, when keratinocytes were treated with 0.1-10.0mM of H2O2, the marked induction of Prx I protein expression was observed above 1 mM H2O2 at a time-dependent manner (after 6 h). The H2O2-induced Prx I expression was abolished by N-acetyl-L-cysteine, a H2O2 scavenger, pre-treatment. In 2D-gel electrophoresis, the active reduced form of Prx I was rapidly transformed into the oxidized, inactive form, and then it restored to the reduced form by H2O2 treatment, suggesting that Prx I was active in responding to the H2O2-induced oxidative stress. CONCLUSION: UVB irradiation up-regulates Prx I by the mediation of H2O2 in the keratinocytes.
Acetylcysteine ; Blotting, Northern ; Blotting, Western ; Electrophoresis ; Humans* ; Hydrogen Peroxide ; Keratinocytes* ; Negotiating ; Oxidative Stress ; Peroxiredoxins* ; RNA, Messenger ; Skin

PURPOSE: We evaluated the hypothesis that the telomerase expression is associated with c-Myc and peroxiredoxin I (Prx I) in patients with prostate cancer. The study determined the link between Prx I, c-Myc and human telomerase reverse transcriptase (hTERT) in prostate cancer cells. MATERIALS AND METHODS: The cDNA of the Prx I gene was obtained by reverse-transcriptase polymerase chain reaction (RT-PCR) amplification. Cotransfections were performed by using a hTERT luciferase reporter plasmid and each expression vector as indicated (c-Myc or Prx I). Empty vectors were used as controls for determining the basal promoter activity. RT-PCR was performed to evaluate the effect of the DEM-induced Prx I mRNA expression. Luciferase assay was performed to evaluate the inhibitory effect of transfected Prx I and the DEM induced Prx I on the transcriptional activity of hTERT in the human prostatic cancer cell lines PC-3 and DU-145. RESULTS: In this study, we found that Prx I could inhibit hTERT expression through direct interaction with c-Myc protein in the prostate cancer cell lines. In addition, it was obvious that Prx I could interact with c-Myc protein. We also found that DEM could induce upregulation of the Prx I mRNA expression and that the increased expression of Prx I could downregulate the expression of hTERT. CONCLUSIONS: Our results demonstrated a direct link between Prx I, c-Myc and hTERT, and we suggest that Prx I regulates cellular immortalization through c-Myc and hTERT, which is activation step in carcinogenesis.
Carcinogenesis ; Cell Line ; DNA, Complementary ; Humans* ; Luciferases ; Peroxiredoxins* ; Plasmids ; Polymerase Chain Reaction ; Prostatic Neoplasms* ; RNA, Messenger ; Telomerase* ; Up-Regulation

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

Atherosclerotic vascular dysfunction is a chronic inflammatory process that spreads from the fatty streak and foam cells through lesion progression. Therefore, its early diagnosis and prevention is unfeasible. Reactive oxygen species (ROS) play important roles in the pathogenesis of atherosclerotic vascular disease. Intracellular redox status is tightly regulated by oxidant and antioxidant systems. Imbalance in these systems causes oxidative or reductive stress which triggers cellular damage or aberrant signaling, and leads to dysregulation. Paradoxically, large clinical trials have shown that non-specific ROS scavenging by antioxidant vitamins is ineffective or sometimes harmful. ROS production can be locally regulated by cellular antioxidant enzymes, such as superoxide dismutases, catalase, glutathione peroxidases and peroxiredoxins. Therapeutic approach targeting these antioxidant enzymes might prove beneficial for prevention of ROS-related atherosclerotic vascular disease. Conversely, the development of specific antioxidant enzyme-mimetics could contribute to the clinical effectiveness.
Atherosclerosis ; Catalase ; Early Diagnosis ; Foam Cells ; Glutathione ; Oxidation-Reduction ; Peroxidases ; Peroxiredoxins ; Reactive Oxygen Species ; Superoxides ; Vascular Diseases* ; Vitamins

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