DJ-1 Protein Expression Research Articles

NRG-1 Stimulates Serum DJ-1 Increase in Breast Cancers.

To explore the relationship between the expression of DJ-1/HER3 and tumor grade in breast cancer, and investigate the effect of HER3 on NRG-1-mediated serum DJ-1 level in vivo. We analyze the expression level of DJ-1 and HER3 in 68 patients with different grades of breast cancer by immunostaining the tissue microarray. Besides, we investigated the serum DJ-1 level by ELISA. We found that the detectable DJ-1 protein expression is decreased, and the HER3 expression is increased in tumor tissue with the progression of breast cancer. There is a significant rise of DJ-1 in serum in vivo with the stimulation of NRG-1. Meanwhile, we found that HER3 knockdown abolishes NRG-1-induced serum DJ-1 increase and HER3 overexpress improves NRG-1-induced serum DJ-1 increase. This study provides a serum biomarker for breast cancer. The results showed that DJ-1 was associated with clinical stage of breast cancer, and NRG-1 increased the dissociation of HER3 and DJ-1, with promoting the level of DJ-1 in peripheral blood. It is suggested that the level of DJ-1 in peripheral blood may be conducive to assess the prognosis of patients with breast cancer and serum DJ-1 levels can serve as an indicator of therapeutic effectiveness for the development of HER3 targeting breast cancer antibody therapies.

DJ-1/PARK7 Impairs Bacterial Clearance in Sepsis

Effective and rapid bacterial clearance is a fundamental determinant of outcomes in sepsis. DJ-1 is a well-established reactive oxygen species (ROS) scavenger. Because cellular ROS status is pivotal to inflammation and bacterial killing, we determined the role of DJ-1 in bacterial sepsis. We used cell and murine models with gain- and loss-of-function experiments, plasma, and cells from patients with sepsis. Stimulation of bone marrow-derived macrophages (BMMs) with endotoxin resulted in increased DJ-1 mRNA and protein expression. Cellular and mitochondrial ROS was increased in DJ-1-deficient (-/-) BMMs compared with wild-type. In a clinically relevant model of polymicrobial sepsis (cecal ligation and puncture), DJ-1-/- mice had improved survival and bacterial clearance. DJ-1-/- macrophages exhibited enhanced phagocytosis and bactericidal activity in vitro, and adoptive transfer of DJ-1-/- bone marrow-derived mononuclear cells rescued wild-type mice from cecal ligation and puncture-induced mortality. In stimulated BMMs, DJ-1 inhibited ROS production by binding to p47phox, a critical component of the NADPH oxidase complex, disrupting the complex and facilitating Nox2 (gp91phox) ubiquitination and degradation. Knocking down DJ-1 (siRNA) in THP-1 (human monocytic cell line) and polymorphonuclear cells from patients with sepsis enhanced bacterial killing and respiratory burst. DJ-1 protein levels were elevated in plasma from patients with sepsis. Higher levels of circulating DJ-1 were associated with increased organ failure and death. These novel findings reveal DJ-1 impairs optimal ROS production for bacterial killing with important implications for host survival in sepsis.

Expression of DJ-1 protein in endometrial carcinoma tissue and its correlation with prognosis

Objective To investigate the expression and clinical significance of DJ-1 protein in the endometrial carcinoma and delineate its functional roles in endometrial carcinoma progression. Methods Expression of DJ-1 was examined with immunohistochemical staining of 69 paraffin-embedded endometrial carcinoma samples who underwent surgery at Hunan province Tumor Hospital. Kaplan-Meier analysis was performed to describe the survival curve. Univariate and multivariate analyses were performed with COX proportional hazard model. Results ⑴ The expression of DJ-1 protein in endometrial carcinoma was significantly higher than that in normal endometrial tissues (P 0.05). Conclusions The high expression of DJ-1 protein in endometrial carcinoma samples demonstrated a significantly positive correlation with the pathological grade, FIGO stage, depth of myometrial invasion, and lymph node metastasis. However, DJ-1 is not enough to be independent prognostic factor for overall survival time. Key words: Endometrial neoplasms/ME; Oncogene proteins/ME; Prognosis

Overexpression of DJ-1 reduces oxidative stress and attenuates hypoxia/reoxygenation injury in NRK-52E cells exposed to high glucose.

Patients with diabetes are more vulnerable to renal ischemia/reperfusion (I/R) injury, which is implicated in hyperglycemia-induced oxidative stress. We previously reported that the hyperglycemia-induced inhibition of DJ-1, a novel oncogene that exhibits potent antioxidant activity, is implicated in the severity of myocardial I/R injury. In the present study, we aimed to explore the role of DJ-1 in hypoxia/reoxygenation (H/R) injury in renal cells exposed to high glucose (HG). For this purpose, NRK-52E cells were exposed to HG (30 mM) for 48 h and then exposed to hypoxia for 4 h and reoxygenation for 2 h, which significantly decreased cell viability and superoxide dismutase (SOD) activity, and increased the malondialdehyde (MDA) content, accompanied by a decrease in DJ-1 protein expression. The overexpression of DJ-1 by transfection with a DJ-1 overexpression plasmid exerted protective effects against HG-induced H/R injury, as evidenced by increased CCK-8 levels and SOD activity, the decreased release of lactate dehydrogenase (LDH) and the decreased MDA content, and increased nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase-1 (HO-1) expression. Similar effects were observed following treatment with the antioxidant, N-acetylcysteine. These results suggest that the overexpression of DJ-1 reduces oxidative stress and attenuates H/R injury in NRK-52E cells exposed to HG.

Neuroprotective effect of resveratrol against brain ischemia reperfusion injury in rats entails reduction of DJ-1 protein expression and activation of PI3K/Akt/GSK3b survival pathway

In the current study, we aimed to investigate the mechanistic role of DJ-1/PI3K/Akt survival pathway in ischemia/reperfusion (I/R) induced cerebral damage and to investigate if the resveratrol (RES) mediates its ischemic neuroptotection through this pathway. RES administration to Sham rats boosted glutathione level and superoxide dismutase activity and downregulated inducible nitric oxide synthase expression without affecting redox levels of DJ-1 forms or components of PI3K/Akt pathway including PTEN, p-Akt or p/p-GSK3b. However, RES pre-administration to I/R rats reduced infarction area, oxidative stress, inflammation and apoptosis. Concomitantly, RES ameliorated the decreased levels of oxidized forms of DJ-1 and enhancing its reduction, increased the nuclear protein expression of Nfr-2 and led to activation of PI3K/Akt survival pathway. In conclusion, overoxidation of DJ-1 is a major factor that contributes to post-I/R cerebral damage and its reduction by RES could explain the neuroprotection offered by RES.

DJ1 expression downregulates in neuroblastoma cells (SK-N-MC) chronically exposed to HIV-1 and cocaine.

Background: HIV-associated neurological disorder (HAND) has long been recognized as a consequence of human immunodeficiency virus (HIV) infection in the brain. The pathology of HAND gets more complicated with the recreational drug use such as cocaine. Recent studies have suggested multiple genetic influences involved in the pathology of addiction and HAND but only a fraction of the entire genetic risk has been investigated so far. In this regard, role of DJ1 protein (a gene linked to autosomal recessive early-onset Parkinson’s disease) in regulating dopamine (DA) transmission and reactive oxygen species (ROS) production in neuronal cells will be worth investigating in HIV-1 and cocaine exposed microenvironment. Being a very abundant protein in the brain, DJ1 could serve as a potential marker for early detection of HIV-1 and/or cocaine related neurological disorder.Methods: In vitro analysis was done to observe the effect of HIV-1 and/or cocaine on DJ1 protein expression in neuroblastoma cells (SK-N-MC). Gene and protein expression analysis of DJ1 was done on the HIV infected and/or cocaine treated SK-N-MC and compared to untreated cells using real time PCR, Western Blot and flow cytometry. Effect of DJ1 dysregulation on oxidative stress was analyzed by measuring ROS production in these cells.Results: Gene expression and protein analysis indicated that there was a significant decrease in DJ1 expression in SK-N-MC chronically exposed to HIV-1 and/or cocaine which is inversely proportional to ROS production.Conclusion: This is the first study to establish that DJ1 expression level in the neuronal cells significantly decreased in presence of HIV-1 and/or cocaine indicating oxidative stress level of DA neurons.

Relationship between DJ-1 and diabetes mellitus-caused influence on cardioprotection induced by ischemic postconditioning in rats

Objective To evaluate the relationship between DJ-1 and diabetes mellitus (DM) -caused influence on cardioprotection induced by ischemic postconditioning in rats. Methods Adult male Sprague-Dawley rats, aged 3 months, weighing 220-250 g, were used in the study.DM was induced by intraperitoneal injection of 1% streptozotocin 60 mg/kg and confirmed by blood glucose≥16.7 mmol/L.Forty-eight rats with DM were randomly divided into 3 groups (n=16 each) using a random number table: sham operation group (group DM-S) , myocardial ischemia-reperfusion (I/R) group (DM-IR) and ischemic postconditioning group (DM-IPO group) . Another 48 normal rats received the equal volume of citrate buffer solution instead and served as control.Those rats were randomly divided into 3 groups (n=16 each) using a random number table: sham operation group (S group) , myocardial I/R group (IR group) and ischemic postconditioning group (IPO group) . At 12 weeks after streptozotocin injection, myocardial I/R was produced by 30 min occlusion of the left anterior descending branch of the coronary artery followed by 120 min reperfusion.Ischemic postconditioning was induced by 3 cycles of 10 s reperfusion followed by 10 s limb ischemia at the end of 30 min limb ischemia.At 120 min of reperfusion, the animals were sacrificed, and hearts were removed for determination of myocardial infarction size (using TTC) , and expression of DJ-1, phosphatase and tensin homologue (PTEN) protein, and phosphorylated Akt (p-Akt) in myocardial tissues (by Western blot) . Results The infarction size was significantly increased in diabetic and nondiabetic rats during myocardial I/R.The expression of DJ-1, PTEN protein and p-Akt was significantly higher during myocardial I/R in nondiabetic rats, and the expression of PTEN protein and p-Akt was up-regulated, and no significant change was found in DJ-1 expression during myocardial I/R in diabetic rats.Ischemic postconditioning reduced infarction size during myocardial I/R and up-regulated the expression of DJ-1 and p-Akt, and down-regulated the expression of PTEN protein in nondiabetic rats, but not in diabetic rats.Compared with nondiabetic rats, the expression of DJ-1 and p-Akt was down-regulated, and the expression of PTEN protein was up-regulated after ischemic postconditioning in diabetic rats. Conclusion The mechanism by which DM abolishes cardioprotection induced by ischemic postconditioning is associated with down-regulation of DJ-1 expression in rats. Key words: Diabetes mellitus; Myocardial reperfusion injury; Ischemic postconditioning; DJ-1

High levels of DJ-1 protein and isoelectric point 6.3 isoform in sera of breast cancer patients.

In patients with cancer and Parkinson’s disease, the DJ-1 protein may be secreted into the serum during the impaired response of the underlying cell-protective mechanisms. In order to determine the clinical significance of DJ-1 protein in the sera of breast cancer patients, we examined blood samples from a breast cancer group (n = 180) and a non-cancerous control group (n = 300). Higher levels of DJ-1 were detected in the breast cancer group (mean level, 42.7 ng/mL) than the control group (28.3 ng/mL) by ELISA (P = 0.019). Higher DJ-1 levels were significantly associated with advanced clinical grade, according to the TNM classification, negative hormone receptor status, and high Ki-67 labeling index, of biopsied materials; samples showed low DJ-1 protein expression despite upregulated DJ-1 mRNA. DJ-1 isoforms could be detected clearly in 17 blood samples (from 11 breast cancer patients, and 6 non-cancerous controls) by 2-D gel electrophoresis and immunoblot analysis. The isoform at the pI of 6.3 showed the highest intensity in all 11 cancer cases. Conversely, in the 6 non-cancerous cases, isoforms other than the pI 6.3 isoform were highly expressed, and there was a significant difference in the isoform pattern between breast cancer cases and controls (P = 0.00025). These data indicate that high levels of DJ-1, probably of isoform at pI 6.3, is a candidate serum marker of breast cancer.

Abstract 19185: Upregulation of DJ-1 Protein after Prolonged Ischemia in a Murine Model for Myocardial Ischemia and Reperfusion

Introduction: Upregulation of cardiac DJ-1 protein might be a cardio-protective mechanism under conditions of ischemia or ischemia and reperfusion by regulating mitogen activated protein (MAP) kinases or inducing enzymes for detoxification and glutathione metabolism. We recently observed that significantly elevated DJ-1 protein expression was associated with decreased expression of phosphatase and tensin homolog (PTEN) and increased phosphorylation of the cell protective kinase AKT (protein kinase B) in human heart tissue samples from patients with chronic ischemic cardiomyopathy. Hypothesis: The expression of DJ-1 protein and its interaction with PTEN and AKT during ischemia or ischemia and reperfusion in a murine heart model might play a cardio-protective role. Methods: The level of DJ-1 was analyzed from the area at risk after 30 or 60-minute ischemia or 30-minute ischemia with 30 or 60 minutes of reperfusion using C57BL/6J mice (n=3). The changes in DJ-1 expression were correlated with the expression of PTEN and AKT and phosphorylation of ERK1/2 (extracellular signal regulated kinase) and P38. The protein levels and their phosphorylation were evaluated by Western blot analysis. Results: Expression of DJ-1 increased significantly after 60 minutes of ischemia while PTEN decreased after 30 minutes of ischemia followed by 30 or 60 minutes of reperfusion both were associated with increased phosphorylation of AKT. The phosphorylation of ERK1/2 was increased at all time points of ischemia or ischemia and reperfusion while phosphorylation of P38 was increased only during ischemia and reperfusion. Conclusions: The increased expression of DJ-1 protein is a potential marker for prolonged ischemia. Although, PTEN expression were not decreased with increased DJ-1 levels, a direct inhibiting effect of DJ-1 on PTEN might increase the phosphorylation of the cell protective AKT during 60-minute ischemia. A DJ-1 independent decrease of PTEN expression might contribute to the increased AKT phosphorylation during ischemia reperfusion. Phosphorylation of ERK1/2 was a sensitive marker of early or late ischemia and ischemia and reperfusion. The role of the DJ-1-AKT interaction in preventing P38 phosphorylation during ischemia needs further investigation.

204P - Dj-1 Protein Expression in Intrinsic Subtype As a Predictor of Pathological Complete Remission After Neoadjuvant Chemotherapy in Breast Cancer Patients

ABSTRACT Aim: The DJ-1 gene was originally identified as an oncogene that, in conjunction with activated ras, and Parkinson's disease is associated with DJ-1/Parkinson protein 7 dysfunction. Neoplastic transformation is associated with the hyperactivity of DJ-1 . DJ-1 overexpression increases the resistance of neoplastic cells to apoptosis by inhibiting the phosphatase and tensin homolog(PTEN)-mediated protein kinase B/Akt pathway and/or other apoptotic pathways,including death-associated protein 6 and homeodomain-interacting protein kinase1. Recent genetic studies showed that, in addition to apoptosis pathways, DJ-1 is also involved in cellular defense against reactive oxygen species. The activity of apoptotic and cellular defense pathways is key in determining drug sensitivity. DJ-1 overexpression is associated with various cancers. We reported that low DJ-1 protein expression is a significant predictor of pCR after chemotherapy in reast cancer patients.(Kawate, BCRT2013) In this time, we will report that we classified Luminal-A subtype to new Lum-A and Lum-B subtype by ki67 and reanalyzed results. Methods: Expression of DJ-1 in pre-therapeutic needle biopsies and surgical specimens obtained from 198 breast cancer cases that received neoadjuvant chemotherapy was determined using immunohistochemistry and in situ hybridization.Chemotherapy comprised epirubicin / cyclophosphamide taxane-based regimens with or without trastuzumab. Univariate and multivariate analyses were used to evaluate the predictive value of DJ-1 on pCR. Results: Low DJ-1 protein expression was detected in 46.0 % (91/198) of all breast cancer cases and in 80.4 % (37/46) of pCR cases. In multivariate analysis, DJ-1 expression(k2 = 16.05, p Conclusions: Low DJ-1 protein expression is a significant predictor of pCR after neoadjuvant chemotherapy at any Sub Type in breast cancer patients. Disclosure: All authors have declared no conflicts of interest.

Effect of DJ-1 overexpression on the proliferation, apoptosis, invasion and migration of laryngeal squamous cell carcinoma SNU-46 cells through PI3K/AKT/mTOR.

The aim of the present study was to explore the effect of DJ-1-mediated PI3K/AKT/mTOR pathway on the proliferation, apoptosis, invasion, migration and other tumor biological characteristics of laryngeal squamous cell SNU-46, through stable transfection and overexpression of the DJ-1 gene. Retrovirus carrying DJ-1 gene was used to stabilize transfected human laryngeal squamous carcinoma SNU-46 cell line, and monoclonal cell line of stably overexpressed DJ-1 protein was screened out by G418. DJ-1 protein expression was determined by western blotting, and changes of p-AKT, p-mTOR and PTEN protein content were detected, followed by the detection of changes in proliferation, apoptosis, invasion, migration and other tumor biological characteristics of laryngeal squamous carcinoma cell line with stably transfected DJ-1 protein overexpression by flow cytometry, CCK-8 method and Transwell. We successfully constructed a laryngeal squamous carcinoma cell line of stably overexpressed DJ-1 protein and termed it SNU-46-DJ-1. After overexpression of DJ-1 protein, the levels of PTEN expression in laryngeal squamous cell SNU-46 decreased and p-AKT and p-mTOR protein expression levels increased. Compared to the untreated SNU-46 cells, the proliferation rate of SNU-46-DJ-1 cells increased (0.834±0.336 vs. 0.676±0.112; p<0.001); invasiveness was enhanced (165.7±13.6 vs. 100.0±17.4; p=0.001), the migration ability was enhanced (207.3±13.1vs.175.3±13.3; p=0.036), and the apoptosis rate decreased (3.533±5.167 vs. 16.397±5.447%; p=0.019). The overexpression of DJ-1 protein in laryngeal squamous carcinoma SNU-46 cells can accelerate proliferation rate, increase the invasion and migration capacity, and reduce apoptosis, by activating the PI3K/AKT/mTOR pathway.

DJ-1 plays an important role in caffeic acid-mediated protection of the gastrointestinal mucosa against ketoprofen-induced oxidative damage

Ketoprofen is widely used to alleviate pain and inflammation in clinical medicine; however, this drug may cause oxidative stress and lead to gastrointestinal (GI) ulcers. We previously reported that nuclear factor erythroid 2-related factor 2 (Nrf2) plays a crucial role in protecting cells against reactive oxygen species, and it facilitates the prevention of ketoprofen-induced GI mucosal ulcers. Recent reports suggested that Nrf2 becomes unstable in the absence of DJ-1/PARK7, attenuating the activity of Nrf2-regulated downstream antioxidant enzymes. Thus, increasing Nrf2 translocation by DJ-1 may represent a novel means for GI protection. In vitro, caffeic acid increases the nuclear/cytosolic Nrf2 ratio and the mRNA expression of the downstream antioxidant enzymes, ϒ-glutamyl cysteine synthetase, glutathione peroxidase, glutathione reductase, and heme oxygenase-1, by activating the JNK/p38 pathway in Int-407 cells. Moreover, knockdown of DJ-1 also reversed caffeic acid-induced nuclear Nrf2 protein expression in a JNK/p38-dependent manner. Our results also indicated that treatment of Sprague–Dawley rats with caffeic acid prior to the administration of ketoprofen inhibited oxidative damage and reversed the inhibitory effects of ketoprofen on the antioxidant system and DJ-1 protein expression in the GI mucosa. Our observations suggest that DJ-1 plays an important role in caffeic acid-mediated protection against ketoprofen-induced oxidative damage in the GI mucosa.

Gender-dimorphic regulation of antioxidant proteins in response to high-fat diet and sex steroid hormones in rats

Despite the fact that gender dimorphism in diet-induced oxidative stress is associated with steroid sex hormones, there are some contradictory results concerning roles of steroid hormones in gender dimorphism. To evaluate the role of gender dimorphism as well as the effects of sex steroid hormones in response to high-fat diet (HFD)-induced oxidative stress, we measured cellular levels of major antioxidant proteins in the liver, abdominal white adipose tissue, and skeletal muscles of Sprague-Dawley rats following HFD or sex hormone treatment using Western blot analysis. Animal experiments revealed that 17β-estradiol, (E2) and dihydrotestosterone (DHT) negatively and positively affected body weight gain, respectively. Interestingly, plasma levels of malondialdehyde (MDA) increased in both E2- and DHT-treated rats. We also observed that cellular levels of classical antioxidant proteins, including catalase, glutathion peroxidase, peroxiredoxin, superoxide dismutase, and thioredoxin, were differentially regulated hormone- and gender-dependent manner in various metabolic tissues. In addition, tissue-specific expression of DJ-1 protein with respect to HFD-induced oxidative stress in association with sex steroid hormone treatment was observed for the first time. Taken together, our data show that females were more capable at overcoming oxidative stress than males through feasible expression of antioxidant proteins in metabolic tissues. Although the exact regulatory mechanism of sex hormones in diet-induced oxidative stress could not be fully elucidated, the current data will provide clues regarding the tissue-specific roles of antioxidant proteins during HFD-induced oxidative stress in association with sex steroid hormones.

DJ-1 is activated in medulloblastoma and is associated with cell proliferation and differentiation.

BackgroundDJ-1 is a key regulator in human tumorigenesis, including brain malignancies. The mechanisms by which DJ-1 contributes to the pathogenesis of medulloblastoma (MB) remain unclear, and its impact on the prognosis for patients with MB has not been identified. The aim of this study was to determine whether the DJ-1 protein is associated with tumorigenesis of MBs, and whether DJ-1 is a valuable factor for predicting the prognosis of patients with MB.MethodsWe collected 66 pairs of MB and adjacent normal cerebellum samples. Expression of DJ-1, Ser 473-phosphorylated-Akt (p-Akt), PTEN, and Ki-67 (MIB-1) was detected by immunohistochemical staining, and the correlation of these immunostaining results with the clinicopathological features of patients with MB was determined.ResultsHigh DJ-1 expression (48.5%, 32/66) in tumor cells of MBs was significantly associated with the classic MB variant (P = 0.003), high proliferative activity (P = 0.002) and undifferentiated tumor (P = 0.001), whereas high p-Akt expression (56.1%, 37/66) was associated with tumor metastasis stage (P = 0.007), undifferentiated tumor (P = 0.007), and high-risk tumor (P = 0.002). High DJ-1 expression also correlated with high p-Akt expression and high MIB-1 index. However, only high levels of DJ-1(P = 0.009) and high MIB-1 index (P = 0.001) were strong independent prognostic factors associated with worse overall survival.ConclusionsAlthough the validity of the preliminary data in this study needs to be confirmed by a larger number of cases, our study indicates that DJ-1, PTEN, and p-Akt might play important roles in cell proliferation and differentiation of MBs. The evaluation of expression of DJ-1 and related proteins might be useful for predicting the prognosis of patients with MB.

Baicalein Prevents 6-Hydroxydopamine-Induced Mitochondrial Dysfunction in SH-SY5Y Cells via Inhibition of Mitochondrial Oxidation and Up-Regulation of DJ-1 Protein Expression

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by progressive loss of dopaminergic (DA) neurons at the substantia nigra. Mitochondrial dysfunction is involved in the mechanism of cell damage in Parkinson’s disease (PD). 6-Hydroxydopamine (6-OHDA) is a dopamine analog which specifically damages dopaminergic neurons. Baicalein has been previously reported to have potential in the treatment of PD. The purpose of the present study was to investigate the mechanism of action of baicalein against 6-OHDA injury in SH-SY5Y cells. The results showed that baicalein significantly alleviated alterations of mitochondrial redox activity and mitochondrial membrane potential induced by 6-OHDA in a dose-dependent manner in SH-SY5Y cells compared with vehicle group. Futhermore, baicalein decreased the production of ROS and upregulated the DJ-1 protein expression in SH-SY5Y cells. In addition, baicalein also inhibited ROS production and lipid peroxidation (IC50 = 6.32 ± 0.03 μM) in rat brain mitochondia. In summary, the underlying mechanisms of baicalein against 6-OHDA-induced mitochondrial dysfunction may involve inhibition of mitochondrial oxidation and upregulation of DJ-1 protein expression.

The transcription factor XBP-1 in neurodegenerative diseases

Parkinson’s disease (PD) is a neurodegenerative disorder that is either associated with an autosomal dominant or recessive mode of inheritance. The latter forms are mostly linked to mutations in the genes of parkin, Pink-1 and DJ-1. Several lines of evidence indicate that DJ-1 could act as an antioxidant while parkin has been characterized as an ubiquitin-ligase. Parkin was reported to interact physically with DJ-1 monomers in oxidative stress conditions but did not promote its ubiquitin-linked proteasomal degradation. This led us to examine whether parkin could control DJ-1 via its function as transcription factor that we documented recently [1]. We have shown [2] that parkin controls DJ-1 by a mechanism independent of its ubiquitin-ligase activity and that this regulation is abolished by PD-related pathogenic mutations. Thus, parkin increases DJ-1 promoter trans-activation, mRNA levels and protein expression via a transcriptional cascade involving p53 repression and subsequent activation of ER-stress induced X-box-binding protein-1S (XBP-1S). Then, XBP-1S physically interacts with DJ-1 promoter, thereby raising DJ-1 mRNA and protein levels. Overall, our study unravels a functional dialogue by which parkin and DJ-1 could control ER-stress response in physiopathological conditions. We will discuss the potential involvement of XBP-1 in other neurodegenerative diseases.

Changes in expression of DJ-1 protein during myocardial ischemia-reperfusion in diabetic rats

Objective To evaluate the changes in the expression of DJ-1 protein during myocardial ischemia-reperfusion (I/R) in diabetic rats.Methods Fifty male Sprague-Dawley rats,weighing 220-280 g,were used in this study.Type 1 diabetes mellitus was induced by intraperitoneal streptozotocin 65 mg/kg and confirmed by fasting blood glucose ＞ 16.7 mmol/L.Forty animals with type 1 diabetes mellitus were randomly divided into 3 groups:diabetes group (group D,n =10),diabetic sham operation group (group DS,n =15) and diabetic I/R group (group DIR,n =15).Another 10 non-diabetic rats in which citrate buffer 6 ml/kg was injected intraperitoneally were served as control group (group C).Myocardial I/R was produced by occlusion of the anterior descending branch of left coronary artery for 30 min followed by 120 min reperfusion in group I/R.At 120 min of reperfusion,5 rats were sacrificed and myocardial specimens were c(on)tained for determination of infarct size in groups DS and DIR,and 10 rats were sacrificed and myocardial specimens were obtained for microscopic examination and for determination of cell apoptosis,malondialdehyde (MDA) content,superoxide dismutase (SOD) activity and expression of DJ-1 and phosphatase and tensin homologue (PTEN) protein.Apoptotic index (AI) was calculated.Linear correlation between the expression of DJ-1 protein and MDA content,SOD activity,AI and expression of PTEN protein was analyzed.Results Compared with group DS,the myocardial infract size was significantly increased in group DIR (P ＜ 0.05).Compared with group C,MDA content and AI were significantly increased,SOD activity was decreased,the expression of DJ-1 was down-regulated,and the expression of PTEN protein was up-regulated in groups D,DS and DIR (P ＜ 0.05).Compared with groups D and DS,MDA content and AI were significantly increased,SOD activity was decreased,the expression of DJ-1 was down-regulated,and the expression of PTEN protein was up-regulated in group DIR (P ＜ 0.05).There was no significant difference in the parameters mentioned above between groups D and DS (P ＞ 0.05).There was linear correlation between the expression of DJ-1 protein and MDA content,SOD activity,AI and expression of PTEN protein and the correlation coefficients (r) were-0.734,0.593,-0.818,and-0.812 in turn.Conclusion Down-regulation of DJ-1 protein expression is involved in myocardial I/R injury in diabetic rats via decreasing anti-oxidative stress responses and upregulating PTEN protein expression. Key words: Intracellular signaling peptides and proteins; Myocardial reperfusion injury; Diabetes mellitus

DJ-1 protein expression as a predictor of pathological complete remission after neoadjuvant chemotherapy in breast cancer patients

Parkinson's disease is associated with DJ-1/Parkinson protein 7 dysfunction. In contrast, hyperactivity of DJ-1 increases the resistance of cancer cells to apoptosis. Recent genetic studies showed that, in addition to apoptosis pathways, DJ-1 is also involved in cellular defense against reactive oxygen species. The activity of apoptotic and cellular defense pathways is key in determining drug sensitivity. DJ-1 overexpression is associated with various cancers. However, we previously found that there were approximately 50 % patients with breast cancers that expressed low levels of DJ-1 protein, despite mRNA upregulation. Furthermore, low DJ-1 expression was a significant predictor of poor clinical outcome in these patients. This study aimed to determine the association between low DJ-1 protein expression and pathological complete remission (pCR) after neoadjuvant chemotherapy in breast cancer patients. Expression of DJ-1 in pre-therapeutic needle biopsies and surgical specimens obtained from 205 breast cancer cases that received neoadjuvant chemotherapy was determined using immunohistochemistry and in situ hybridization. Chemotherapy comprised epirubicin/cyclophosphamide taxane-based regimens with or without the inclusion of trastuzumab. Univariate and multivariate analyses were used to evaluate the predictive value of DJ-1 on pCR. Low DJ-1 protein expression was detected in 45.3 % (93/205) of all breast cancer cases and in 79.6 % (39/49) of pCR cases, irrespective of maintained mRNA levels. DJ-1 expression [hazard ratio (HR): 1.36; 95 % confidence interval (CI): 1.01-1.84] and HER2 status (HR: 0.84; 95 % CI: 0.62-1.14), in contrast to histological grade, hormone receptors status, Ki-67 labeling index, and intrinsic subtype, were significant predictors of pCR. Low DJ-1 expression predicted pCR in luminal A (P = 0.0004), luminal B (P = 0.0194), and triple negative (P = 0.0143) subtypes breast cancer patients and in patients receiving additional trastuzumab treatment (P = 0.008). In conclusion, low DJ-1 protein expression is a significant predictor of pCR after neoadjuvant chemotherapy in breast cancer patients.

Expression of DJ-1 proteins in placentas from women with severe preeclampsia

ObjectiveLately, DJ-1 has been identified as a novel mediator of hypoxia-induced cellular responses. The aim of this study was to determine the difference of DJ-1 expression in the placentas of women with normal and preeclamptic pregnancies. Study designDJ-1 mRNA expression was quantified by quantitative reverse transcription polymerase chain reaction (RT-PCR). Also, immnoperoxidase and immunofluorescent staining for DJ-1 was performed on 11 normal and 12 preeclamptic placental tissues. ResultsThe expression of mRNA of DJ-1 was significantly higher in the study group than in the control group. The immunoreactivity was especially higher in the syncytiotrophoblast of preeclamptic placentas compared to the control group. ConclusionOverexpression of the DJ-1 protein in the placentas of severe PE patients is thought to be a causative or compensatory mechanism in response to hypoxia, and this finding might contribute to a better understanding of the pathophysiology of preeclampsia.

Effect of DJ-1 siRNA on biological behavior of human lung squamous carcinoma SK-MES-1 cells

RNA interference technology (siRNA) was used to inhibit the expression of DJ-1 gene in lung squamous cell carcinoma SK-MES-1 cells, and the cell biological behaviors were investigated to explore the function of DJ-1 gene. A targeted DJ-1 siRNA lentiviral vector with a green fluorescent protein (GFP) as a reporter was constructed. The constructed DJ-1 siRNA and control-siRNA vectors were infected into SK-MES-1 cells as experimental (DJ-1 siRNA) and control (Control siRNA) groups, respectively. The DJ-1 protein expression was determined by Western blot. The cell proliferation capability was measured with methyl thiazolyl tetrazolium (MTT). The cell cycle was analyzed by flow cytometry. The capability of cell migration was determined by Transwell method. Compared with control-siRNA and blank-control groups, the protein expression of DJ-1 gene was down-regulated, the capability of cell proliferation was obviously inhibited (P<0.01), the cell cycle was arrested with increased number of G1- and G2-phase cells and reduced number of S-phase cells, and the capability of cell migration was significantly decreased (P<0.01) in the DJ-1 siRNA-infected cells. DJ-1 gene might play a role in promoting cell proliferation and cell migration capability in vitro in lung cancer SK-MES-1 cells.