Calreticulin transacetylase mediated upregulation of thioredoxin by 7,8-diacetoxy-4-methylcoumarin enhances the antioxidant potential and the expression of vascular endothelial growth factor in peripheral blood mononuclear cells

Extensive research carried out in our group on polyphenolic acetates (PAs) substantiated the potential role of PAs in causing diverse biological and pharmacological actions. Our earlier investigations firmly established the calreticulin transacetylase (CRTAase) catalyzed activation of nitric oxide synthase (NOS) by PAs. In this report, we have studied the effect of 7,8-diacetoxy-4-methylcoumarin (DAMC, a model PA) and other acetoxy coumarins on the thioredoxin and VEGF expression in human peripheral blood mononuclear cells (PBMCs), with a view to substantiate our earlier observation that DAMC was a superb inducer of angiogenesis. Real time RT-PCR analysis revealed the enhanced expression of thioredoxin reductase (TRXR) and diminished expression of thioredoxin interacting protein (TRXIP) leading to the increased expression and activity of thioredoxin (TRX) in PBMCs due to the the action of DAMC. The fact that TRX activity of PBMCs was enhanced by various acetoxy coumarins in tune with their affinity to CRTAase as substrate, suggested the possible activation of TRX due to acetylation. The overexpression of thioredoxin was found to correlate with that of VEGF as proved by real time RT-PCR and VEGF -ELISA results, apart from the DAMC-caused enhanced production of NO acting as an inducer of VEGF. Moreover, the intracellular ROS levels were also found to be reduced drastically, by DAMC thus reducing the oxidative stress in cells. These observations strongly evidenced the crucial role of TRX in DAMC-induced tissue angiogenesis with the involvement of VEGF.     

Identification of thioredoxin-binding protein-2/vitamin D(3) up-regulated protein 1 as a negative regulator of thioredoxin function and expression.

Recent works have shown the importance of reduction/oxidation (redox) regulation in various biological phenomena. Thioredoxin (TRX) is one of the major components of the thiol reducing system and plays multiple roles in cellular processes such as proliferation, apoptosis, and gene expression. To investigate the molecular mechanism of TRX action, we used a yeast two-hybrid system to identify TRX-binding proteins. One of the candidates, designated as thioredoxin-binding protein-2 (TBP-2), was identical to vitamin D(3) up-regulated protein 1 (VDUP1). The association of TRX with TBP-2/VDUP1 was observed in vitro and in vivo. TBP-2/VDUP1 bound to reduced TRX but not to oxidized TRX nor to mutant TRX, in which two redox active cysteine residues are substituted by serine. Thus, the catalytic center of TRX seems to be important for the interaction. Insulin reducing activity of TRX was inhibited by the addition of recombinant TBP-2/VDUP1 protein in vitro. In COS-7 and HEK293 cells transiently transfected with TBP-2/VDUP1 expression vector, decrease of insulin reducing activity of TRX and diminishment of TRX expression was observed. These results suggested that TBP-2/VDUP1 serves as a negative regulator of the biological function and expression of TRX. Treatment of HL-60 cells with 1alpha, 25-dihydroxyvitamin D(3) caused an increase of TBP-2/VDUP1 expression and down-regulation of the expression and the reducing activity of TRX. Therefore, the TRX-TBP-2/VDUP1 interaction may be an important redox regulatory mechanism in cellular processes, including differentiation of myeloid and macrophage lineages.     

Intracellular uptake of an antitumor-active azole-bridged dinuclear platinum(II) complex in cisplatin-resistant tumor cells

A cationic azolato-bridged dinuclear platinum(II) complex, [{cis-Pt(NH₃)₂}₂(μ-OH)(μ-methyl-pyrazolate)]²⁺ (4M-PzPt), was developed to overcome resistance to cisplatin (CDDP). This study aimed to assess the cytotoxicity of 4M-PzPt against a CDDP-resistant cell line, H4-II-E/CDDP, and compare the intracellular accumulation of CDDP and 4M-PzPt. H4-II-E and H4-II-E/CDDP displayed similar sensitivity to 4M-PzPt; however, the sensitivity of H4-II-E/CDDP to CDDP was approximately 19-fold lower than that of H4-II-E. The difference in the sensitivity to both platinum complexes corresponded with the difference in the amount of intracellular platinum accumulation after exposure to CDDP or 4M-PzPt in both cell lines. In H4-II-E, HepG2, and HuH-7 cells, the intracellular uptake of CDDP and 4M-PzPt occurred via active transport and passive transport. Results of co-exposure with the transport inhibitors ouabain, tetraethylammonium, and cimetidine indicated that the intracellular uptake of CDDP was dependent on Na⁺/K⁺-ATPase and that of 4M-PzPt was dependent on organic cation transporters (OCTs), probably OCT1. This study suggested that 4M-PzPt could inhibit the growth of a CDDP-resistant tumor via an intracellular uptake mechanism different from that of CDDP.     

Expression of thioredoxin in bleomycin-injured airway epithelium: possible role of protection against bleomycin induced epithelial injury

Bleomycin (BLM) is an anticancer drug, administration of which leads to severe lung injury, in which the generation of intracellular reactive oxygen species (ROS) is thought to participate in that. Thioredoxin (TRX) has been found to function as a powerful antioxidant by reducing ROS, and thus protecting against ROS-mediated cytotoxicity. However, a protective role of TRX in BLM-induced lung injury has not been determined. In the present study, we therefore attempted to clarify this issue. Human TRX-transfected L929 murine fibrosarcoma cells were more resistant to BLM-induced cytotoxicity than the parental and the control transfected cells, indicating that TRX plays the protective role in BLM-induced cytotoxicity. Next, we examined TRX expression in the lung of in vivo model of BLM-induced lung injury and BLM-stimulated bronchial epithelial cells in vitro to clarify the role of TRX in BLM-induced lung injury. In the lungs of BLM-treated mice, the expression of TRX was strongly induced in bronchial epithelial cells. TRX expression was also up-regulated at both the mRNA and protein levels in cultured BEC with the treatment with BLM. However, the expression of other major antioxidants, such as Cu/Zn-SOD, Mn-SOD, catalase and glutathione peroxidase, was not affected by BLM. These observations suggest that the cellular reduction and oxidation (redox) state modified by TRX is involved in the BLM resistancy and the induction of TRX in bronchial epithelial cells might play a protective role in BLM-induced lung injury.     

Entamoeba histolytica thioredoxin reductase: Molecular and functional characterization of its atypical properties

Background

Entamoeba histolytica, an intestinal protozoan that is the causative agent of amoebiasis, is exposed to elevated amounts of highly toxic reactive oxygen and nitrogen species during tissue invasion. Thioredoxin reductase catalyzes the reversible transfer of reducing equivalents between NADPH and thioredoxin, a small protein that plays key metabolic functions in maintaining the intracellular redox balance.

Methods

The present work deals with in vitro steady state kinetic studies aimed to reach a better understanding of the kinetic and structural properties of thioredoxin reductase from E. histolytica (EhTRXR).

Results

Our results support that native EhTRXR is a homodimeric covalent protein that is able to catalyze the NAD(P)H-dependent reduction of amoebic thioredoxins and S‐nitrosothiols. In addition, the enzyme exhibited NAD(P)H dependent oxidase activity, which generates hydrogen peroxide from molecular oxygen. The enzyme can reduce compounds like methylene blue, quinones, ferricyanide or nitro-derivatives; all alternative substrates displaying a relative high capacity to inhibit disulfide reductase activity of EhTRXR.

Conclusions and general significance

Interestingly, EhTRXR exhibited kinetic and structural properties that differ from other low molecular weight TRXR. The TRX system could play an important role in the parasite defense against reactive species. The latter should be critical during the extra intestinal phase of the amoebic infection. So far we know, this is the first in depth characterization of EhTRXR activity and functionality.     

Nitric oxide confers cisplatin resistance in human lung cancer cells through upregulation of aldo-keto reductase 1B10 and proteasome

Abstract

In this study, we show that exposure of human lung cancer A549 cells to cisplatin (cis-diamminedichloroplatinum, CDDP) promotes production of nitric oxide (NO) through generation of reactive oxygen species (ROS) and resulting upregulation of inducible NO synthase (iNOS). The incubation of the cells with a NO donor, diethylenetriamine NONOate, not only reduced the CDDP-induced cell death and apoptotic alterations (induction of CCAAT-enhancer-binding protein homologous protein and caspase-3 activation), but also elevated proteolytic activity of 26S proteasome, suggesting that the activation of proteasome function contributes to the reduction of CDDP sensitivity by NO. Monitoring expression levels of six aldo-keto reductases (AKRs) (1A1, 1B1, 1B10, 1C1, 1C2, and 1C3) during the treatment with the NO donor and subsequent CDDP sensitivity test using the specific inhibitors also proposed that upregulation of AKR1B10 by NO is a key process for acquiring the CDDP resistance in A549 cells. Treatment with CDDP and NO increased amounts of nitrotyrosine protein adducts, indicative of peroxynitrite formation, and promoted the induction of AKR1B10, inferring a relationship between peroxynitrite formation and the enzyme upregulation in the cells. The treatment with CDDP or a ROS-related lipid aldehyde, 4-hydroxy-2-nonenal, facilitated the iNOS upregulation, which was restored by increasing the AKR1B10 expression. In contrast, the facilitation of NO production by CDDP treatment was hardly observed in AKR1B10-overexpressing A549 cells and established CDDP-resistant cancer cells (A549, LoVo, and PC3). Collectively, these results suggest the NO functions as a key regulator controlling AKR1B10 expression and 26S proteasome function leading to gain of the CDDP resistance.     

Analysis of the inhibition of mammalian thioredoxin, thioredoxin reductase, and glutaredoxin by cis-diamminedichloroplatinum (II) and its major metabolite, the glutathione-platinum complex.

Several studies have demonstrated a correlation between cellular toxicity of cis-diamminedichloroplatinum (II) (cisplatin, CDDP) and inhibited intracellular activity of the thioredoxin system, i.e., thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH. Conversely, increased cellular activity of the Trx system confers resistance to CDDP. In this study, we have analyzed the interaction of CDDP with Trx and TrxR in order to clarify the mechanism. The inhibition with time-dependent kinetics by CDDP of NADPH-reduced (but not oxidized) TrxR was irreversible, strongly suggesting covalent modification of the reduced selenocysteine-containing active site. Assuming second order kinetics, the rate constant of TrxR inhibition by CDDP was 21 +/- 3 M(-1) x s(-1). Transplatin was found to be an even more efficient inhibitor, with a second order rate constant of 84 +/- 22 M(-1) x s(-1), whereas carboplatin (up to 1 mM) gave no inhibition of the enzyme under the same conditions. Escherichia coli Trx or human or bacterial glutaredoxin (Grx) activities were in comparison only slightly or not at all inhibited by either CDDP, transplatin, or carboplatin. However, glutaredoxins were found to be inhibited by the purified glutathione adduct of cisplatin, bis-(glutathionato)platinum(II) (GS-Platinum complex, GS-Pt), with an IC50 = 350 microM in the standard beta-hydroxyethyl disulfide-coupled assay for human Grx. Also the mammalian Trx system was inhibited by GS-Pt with similar efficiency (IC(50) = 325 microM), whereas neither the E. coli Trx system nor glutathione reductase were inhibited. Formation of GS-Pt is a major route for cellular elimination of CDDP. The fact that GS-Pt inhibits the mammalian Trx as well as Grx systems shows that CDDP may exert effects at several stages of its metabolism, including after conjugation with GSH, which are intimately linked with the cellular disulfide/dithiol redox regulatory systems.     

Regulatory roles of thioredoxin in oxidative stress-induced cellular responses

Abstract

Thioredoxin (TRX) is a small ubiquitous and multifunctional protein having a redox-active dithiol/disulfide within the conserved active site sequence –Cys–Gly–Pro–Cys–. TRX is induced by a variety of oxidative stimuli, including UV irradiation, inflammatory cytokines and chemical carcinogens, and has been shown to play crucial roles in the regulation of cellular responses such as gene expression, cell proliferation and apoptosis. Overexpression of TRX protects cells from cytotoxicity elicited by oxidative stress in both in vitro and in vivo models. The regulatory mechanism of TRX expression and activity is also being elucidated. Recently, TRX binding protein-2 (TBP-2)/vitamin D3 up-regulated protein 1 (VDUP1) was identified as a negative regulator of TRX. The analysis of TRX promoter region has revealed putative regulatory elements responsible for oxidative stress. Thus, the modulation of TRX functions may be a new therapeutic strategy for the treatment of oxidative stress-mediated diseases.     

Cisplatin-resistant osteosarcoma cell-derived exosomes confer cisplatin resistance to recipient cells in an exosomal circ_103801-dependent manner

Studies have shown that exosomes can mediate the chemoresistance of drug-resistant cells by transmitting circular RNAs (circRNAs). However, the role of exosome-derived hsa_circ_103801 (exosomal hsa_circ_103801) in osteosarcoma (OS) remains unclear. The level of hsa_circ_103801 was upregulated in the serum exosomes from patients with OS, and OS patients with high hsa_circRNA_103801 expression had a shorter survival time relative to patients with low hsa_circ_103801 expression. The expression of hsa_circ_103801 was upregulated in cisplatin-resistant MG63 (MG63/CDDP) cells compared with that in MG63 cells. In addition, hsa_circ_103801 was highly enriched in exosomes derived from CDDP-resistant OS cells and could be delivered to MG63 and U2OS cells through exosomes. Exosomes derived from CDDP-resistant cells were shown to reduce the sensitivity of MG63 and U2OS cells to CDDP, inhibit apoptosis, and increase the expression of multidrug resistance-associated protein 1 and P-glycoprotein. Moreover, exosomal hsa_circ_103801 could strengthen the promotive effect of exosomes on the chemoresistance of MG63 and U2OS cells to CDDP. Hence, serum exosomal hsa_circ_103801 may serve as an effective prognostic biomarker for OS, and exosomal hsa_circ_103801 could be a potential target for overcoming OS chemoresistance.     

硫氧还蛋白还原酶1(TrxR1)在胃癌中的表达及对胃癌细胞生长的影响*

目的: 探讨胃癌组织硫氧还蛋白还原酶1(TrxR1)表达与生存时间的关系及其对胃癌细胞生长的影响。方法: 用Real-time PCR法检测76例胃癌组织及癌旁TrxR1 mRNA表达,并分析其与胃癌患者临床病理特征及预后的关系;随机选取3例胃癌组织及癌旁组织,采用免疫组化法、Western blot法检测TrxR1蛋白表达。采用Western blot法和Real-time PCR法检测胃癌细胞系及人胃粘膜上皮细胞中TrxR1的表达。采用小RNA干扰序列(siRNA)处理AGS细胞,根据处理方法不同将AGS细胞分为3组:阴性对照组:转染NC-siRNA、TRXR1 siRNA干扰1组:转染TRXR1-siRNA1、TRXR1 siRNA干扰2组:转染TRXR1-siRNA2。使用Real-time PCR法检测各组AGS细胞中TrxR1 mRNA的表达,克隆形成试验和MTT法检测AGS细胞生长情况。结果: 胃癌组织中TrxR1 mRNA和蛋白表达量均显著性上调,TrxR1主要定位于细胞质中。TrxR1高表达与患者TNM分期及淋巴结转移有关,且TrxR1高表达组患者的中位生存时间短于低表达组(P＜0.05)。胃癌细胞中TrxR1表达量高于人胃粘膜上皮细胞系中的表达。TRXR1-siRNA1组AGS细胞和TRXR1-siRNA2组AGS细胞中TrxR1 mRNA和蛋白与NC-siRNA组相比均显著性降低(P＜0.05),且AGS细胞克隆形成与增殖能力均降低(P＜0.05)。结论: 胃癌组织中TrxR1高表达提示患者预后不良,沉默TrxR1能抑制胃癌细胞的增殖。     

Acetyl-L-carnitine suppresses apoptosis of thioredoxin 2-deficient DT40 cells

To elucidate the mechanism by which l-carnitine and related metabolites inhibited mitochondria-dependent apoptosis, we used conditional TRX2-knockout DT40 cells (TRX2^−/−) and compared the properties of signaling pathways leading to apoptosis in the wild and TRX2^−/− cells. Caspase-3 and 9, but not caspase-8, were strongly activated in TRX2^−/− cells but not in wild cells. TRX2^−/− cells generated large amounts of reactive oxygen species that markedly decreased cellular glutathione levels both in cytosol and mitochondria. We found that the critical thiol groups of adenine nucleotide translocator (ANT) were oxidized more easily in TRX2^−/− cells than in wild cells and that the reduced form, but not oxidized form, of ANT selectively bound to TRX2. Cytochrome c and SOD1 were released from mitochondria more easily in TRX2^−/− cells than in wild cells. All these phenomena observed with TRX2^−/− cells were effectively inhibited by acetyl-l-carntine but not l-carnitine. Thus, acetyl-l-carnitine effectively suppressed the oxidative stress in and around mitochondria thereby preventing mitochondrial signaling pathway leading to apoptosis.     

Thioredoxin and thioredoxin binding protein 2 in the liver

Thioredoxin (TRX) is a 12-kDa protein with redox-active dithiol in the active site -Cys-Gly-Pro-Cys- and constitutes a major thiol reducing system. TRX protects cells from stress-induced damage through antioxidative, antiapoptotic, and anti-inflammatory effect. In animal models, thioacetamide (TAA)-induced acute hepatitis and TAA-induced liver fibrosis was attenuated in TRX transgenic (TRXTG) mice. Plasma level of TRX is a good marker for hepatitis and nonalcoholic steatohepatitis (NASH) in human patients. Recently, we identified TRX binding protein 2 (TBP2) in a yeast two-hybrid screening. TBP2 regulates both the expression and reducing activity of TRX as well as cell growth. TBP2 knockout (TBP2KO) mice showed disorder in lipid metabolism. TBP2 plays a multiple role on cell growth and lipid and glucose metabolism. Thus, TRX and TBP2 play important roles in the pathophysiology of liver diseases, including NASH, indicating that ratio of TRX and TBP2 expression could be a novel marker of liver diseases like NASH.     

Involvement of thioredoxin reductase 1 in the regulation of redox balance and viability of rheumatoid synovial cells

Rheumatoid arthritis (RA), a chronic and systemic disease of unknown etiology, is characterized by hyperplasia of synovial cells, which ultimately lead to the destruction of cartilage and bone. To elucidate the molecular mechanisms that lead to RA, we analyzed synovial cells established from patients with RA by oligonucleotide microarrays. Gene expression profiles clearly suggested that oxidative stress is enhanced in RA synovial cells, which was confirmed by measuring cellular levels of reactive oxygen species. One of the highly up-regulated proteins in RA synovial cells was thioredoxin reductase 1 (TRXR1), a protein that plays an important role in antioxidant defense system. Subsequent analysis demonstrated that TRXR1 suppresses hydrogen peroxide and inhibits apoptosis of RA synovial cells. Thus, our results reveal a novel pathophysiologic function of RA synovial cells as a generator of oxidative stress, and a self-defense mechanism against self-generated oxidative stress.     

Impact of intracellular chloride concentration on cisplatin accumulation in sensitive and resistant GLC4 cells

Resistance to cisplatin [cis-diamminedichloroplatinum(II), CDDP] chemotherapy is a major problem in the clinic. Understanding the molecular basis of the intracellular accumulation of CDDP and other platinum-based anticancer drugs is of importance in delineating the mechanism of resistance to these clinically important therapies. Different molecular mechanisms may coexist, but defective uptake of CDDP is one of the most consistently identified characteristics of cells selected for CDDP resistance. We have studied the impact of intracellular chloride concentration on platinum-based compound accumulation in the human GLC4, GLC4/CDDP, and K562 tumor cell lines. We show that (1) a decrease of intracellular chloride concentration yielded an increase of CDDP accumulation and vice versa and (2) the intracellular chloride concentration in GLC4/CDDP cells is higher than in sensitive cells, whereas CDDP accumulation shows the opposite behavior. The identification of chloride as a critical determinant of CDDP intracellular accumulation and the molecular mechanisms by which CDDP-resistant cells modulate chloride concentration may allow alternative therapeutic approaches. Our findings indicate that increase of intracellular chloride concentration may be a major determinant of CDDP resistance.     

Temocapril treatment ameliorates autoimmune myocarditis associated with enhanced cardiomyocyte thioredoxin expression

Thioredoxin (TRX) is a redox regulatory protein that protects cells from various stresses. Angiotensin-converting enzyme (ACE) inhibitor was reported to enhance endogenous antioxidant enzyme activities. This study was carried out to investigate whether temocapril, a novel non-sulfhydryl containing ACE inhibitor, reduces the severity of myocarditis via redox regulation mechanisms involving TRX. Western blot showed that temocapril enhanced cytosolic redox regulatory protein TRX expression, but neither mitochondrial TRX2 nor antioxidant enzymes, such as copper-zinc superoxide dismutase (Cu/Zn-SOD) or manganese superoxide dismutase (Mn-SOD) expression, was increased by the preconditioning treatment. In rats with experimental autoimmune myocarditis (EAM), the protein carbonyl content, a marker of cellular protein oxidation, was increased accompanied with enhanced TRX expression. An immunohistochemical study showed that TRX stain was enhanced in infiltrating inflammatory cells and in damaged myocytes. The severity of the myocarditis and the protein carbonyl contents were less increased in temocapril treatment (10 mg/kg/day, orally) from day 1 to day 21 in which TRX was up regulated when the inflammation started, but not in temocapril treatment from day 15–21 in which TRX was not up-regulated when the inflammation started. The results suggest that TRX and the redox state modified by TRX may play a crucial role in the pathophysiology of EAM. Temocapril ameliorates myocarditis associated with inducing TRX increase in a preconditioning manner, although the mechanism of TRX induction by temocapril remains to be elucidated.     

Redox regulation of Ito remodeling in diabetic rat heart

Oxidative stress and the resulting change in cell redox state are proposed to contribute to pathogenic alterations in ion channels that underlie electrical remodeling of the diseased heart. The present study examined whether K(+) channel remodeling is controlled by endogenous oxidoreductase systems that regulate redox-sensitive cell functions. Diabetes was induced in rats by streptozotocin, and experiments were conducted after 3-5 wk of hyperglycemia. Spectrophotometric assays of ventricular tissue extracts from diabetic rat hearts revealed divergent changes in two major oxidoreductase systems. The thioredoxin (TRX) system in diabetic rat heart was characterized by a 52% decrease in TRX reductase (TRXR) activity from control heart (P < 0.05), whereas TRX activity was 1.7-fold greater than control heart (P < 0.05). Diabetes elicited similar changes in the glutaredoxin (GRX) system: glutathione reductase was decreased 35% from control level (P < 0.05), and GRX activity was 2.5-fold greater than in control heart (P < 0.05). The basal activity of glucose-6-phosphate dehydrogenase, which generates NADPH required by the TRX and GRX systems, was not altered by diabetes. Voltage-clamp studies showed that the characteristically decreased density of the transient outward K(+) current (I(to)) in isolated diabetic rat myocytes was normalized by in vitro treatment with insulin (0.1 microM) or the metabolic activator dichloroacetate (1.5 mM). The effect of these agonists on I(to) was blocked by inhibitors of glucose-6-phosphate dehydrogenase. Moreover, inhibitors of TRXR, which controls the reducing activity of TRX, also blocked upregulation of I(to) by insulin and dichloroacetate. These data suggest that K(+) channels underlying I(to) are regulated in a redox-sensitive manner by the TRX system and the remodeling of I(to) that occurs in diabetes may be due to decreased TRXR activity. We propose that oxidoreductase systems are an important repair mechanism that protects ion channels and associated regulatory proteins from irreversible oxidative damage.     

Vitamin D3 up-regulated protein 1 mediates oxidative stress via suppressing the thioredoxin function

As a result of identifying the regulatory proteins of thioredoxin (TRX), a murine homologue for human vitamin D3 up-regulated protein 1 (VDUP1) was identified from a yeast two-hybrid screen. Cotransfection into 293 cells and precipitation assays confirmed that mouse VDUP1 (mVDUP1) bound to TRX, but it failed to bind to a Cys32 and Cys35 mutant TRX, suggesting the redox-active site is critical for binding. mVDUP1 was ubiquitously expressed in various tissues and located in the cytoplasm. Biochemical analysis showed that mVDUP1 inhibited the insulin-reducing activity of TRX. When cells were treated with various stress stimuli such as H2O2 and heat shock, mVDUP1 was significantly induced. TRX is known to interact with other proteins such as proliferation-associated gene and apoptosis signal-regulating kinase 1. Coexpression of mVDUP1 interfered with the interaction between TRX and proliferation-associated gene or TRX and ASK-1, suggesting its roles in cell proliferation and oxidative stress. To investigate the roles of mVDUP1 in oxidative stress, mVDUP1 was overexpressed in NIH 3T3 cells. When cells were exposed to stress, cell proliferation was declined with elevated apoptotic cell death compared with control cells. In addition, c-Jun N-terminal kinase activation and IL-6 expression were elevated. Taken together, these results demonstrate that mVDUP1 functions as an oxidative stress mediator by inhibiting TRX activity.