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Rishabh Singh,1 James C Watchorn,2 Alexander Zarbock,3 Lui G Forni4,5 1Department of Surgery, Royal Surrey Hospital, Guildford, Surrey, UK; 2Intensive Care Unit, Royal Berkshire NHS Foundation Trust, Reading, Berkshire, UK; 3Department of Anesthesiology, Intensive Care and Pain Medicine, University Hospital Münster, Münster, Germany; 4Critical Care Unit, Royal Surrey Hospital, Guildford, Surrey, UK; 5School of Medicine, Kate Granger Building, University of Surrey, Guildford, UKCorrespondence: Lui G Forni, Email luiforni@nhs.netAbstract: Acute kidney injury (AKI) is a common complication after surgery and the more complex the surgery, the greater the risk. During surgery, patients are exposed to a combination of factors all of which are associated with the development of AKI. These include hypotension and hypovolaemia, sepsis, systemic inflammation, the use of nephrotoxic agents, tissue injury, the infusion of blood or blood products, ischaemia, oxidative stress and reperfusion injury. Given the risks of AKI, it would seem logical to conclude that early identification of patients at risk of AKI would translate into benefit. The conventional markers of AKI, namely serum creatinine and urine output are the mainstay of defining chronic kidney disease but are less suited to the acute phase. Such concerns are compounded in surgical patients given they often have significantly reduced mobility, suboptimal levels of nutrition and reduced muscle bulk. Many patients may also have misleadingly low serum creatinine and high urine output due to aggressive fluid resuscitation, particularly in intensive care units. Over the last two decades, considerable information has accrued with regard to the performance of what was termed “novel” biomarkers of AKI, and here, we discuss the most examined molecules and performance in surgical settings. We also discuss the application of biomarkers to guide patients’ postoperative care.Plain Language Summary: Kidney damage is common after major surgery with a recent study showing almost 1 in 5 patients suffer kidney damage. The usual tests for measuring kidney function are excellent in the outpatient but not so good in acute scenario’s. Therefore, there has been a lot of interest in new markers of kidney damage (so-called novel biomarkers) which perform well acutely and allow earlier detection of damage allowing treatment to be started earlier. This article summarises the currently available biomarkers for use post-operatively and points out the different information that can be achieved by using them routinely.Keywords: acute kidney injury, biomarkers, DKK-3, dickkopf-3, suPAR, soluble urokinase plasminogen activator receptor, IGFBP-7, insulin growth factor binding protein-7 and TIMP-2, tissue inhibitor of metalloproteinases-2, PENK, proenkephalin A 119-159, NGAL, neutrophil gelatinase-associated lipocalin, KIM-1, kidney injury molecule-1, CCL14, chemokine 14

The human Dickkopf (DKK) family includes four main secreted proteins, DKK-1, DKK-2, DKK-3, and DKK-4, as well as the DKK-3 related protein soggy (Sgy-1 or DKKL1). These glycoproteins play crucial roles in various biological processes, and especially modulation of the Wnt signaling pathway. DKK-3 is distinct, with its multifaceted roles in development, stem cell differentiation and tissue homeostasis. Intriguingly, DKK-3 appears to have immunomodulatory functions and a complex role in cancer, acting as either a tumor suppressor or an oncogene, depending on the context. DKK-3 is a promising diagnostic and therapeutic target that can be modulated by epigenetic reactivation, gene therapy and DKK-3-blocking agents. However, further research is needed to optimize DKK-3-based therapies. In this review, we comprehensively describe the known functions of DKK-3 and highlight the importance of context in understanding and exploiting its roles in health and disease. [ABSTRACT FROM AUTHOR]

Vitamin D3 helps to reduce oxidative stress levels, as does Dickkopf-3 (DKK-3) glycoprotein, which is released in the kidney's tubular membrane during stress and helps promote tubulointerstitial fibrosis. The aim is to investigate how vitamin D supplementation affects serum DKK-3 levels and biochemical indicators of renal function in CKD patients in stage III. The study had inclusion criteria for 180 participants of both sexes, aged between 20 and 35 years. They were divided into 3 groups: 60 healthy participants as control, 60 CKD patients in stage III (without vitamin D3 supplements), and 60 others (with three months of 5,000 IU of weekly vitamin D3 supplements). DKK-3 levels in serum, vitamin D3, and parathyroid hormone were examined, and kidney function was tested. Findings indicated a significant increase in levels of DKK-3 serum for patients in the 2 and 3 groups with CKD compared with control. Additionally, outcomes revealed significantly lower DKK-3 (41%) in the third group of patients who took vitamin D compared to the second group (120%) without vitamin D supplements. There was also an improvement in several kidney functions for the third group, and the relationships revealed a significant inverse association between the levels of vitamin D3 and serum DKK3. Also, there is a significant inverse association with urea and creatinine levels; additionally, there is a significant positive association with glomerular filtration rate and calcium. In conclusion, DKK-3 may be a potential biomarker for the development of CKD. Furthermore, vitamin D administration improved kidney function and DKK-3 levels in individuals with stage III CKD. As a result, vitamin D can assist in reducing the development of chronic kidney disease. [ABSTRACT FROM AUTHOR]

Malgré une grande hétérogénéité des situations cliniques, la définition de l'insuffisance rénale aiguë (IRA) est unique et son diagnostic repose essentiellement sur l'augmentation de la créatininémie et/ou la diminution de la diurèse. À l'inverse de l'évolution sur les marqueurs biologiques de l'infarctus du myocarde observée depuis plus de 50 ans, c'est toujours la créatinine "marqueur fonctionnel" qui sert de gold standard biologique pour le diagnostic de l'IRA. Cependant, sous le terme d'IRA, sont regroupées des situations cliniques très hétérogènes d'un point de vue étioIogique, physiopathologique, de durée, d'évolution et d'éventuelles complications associées. Depuis une quinzaine d'années des nouveaux biomarqueurs potentiels sont étudiés et semblent prometteurs. Contrairement à la troponine qui est augmentée dans tous les types d'infarctus du myocarde, ces nouveaux biomarqueurs présentent des sensibilités et spécificités différentes en fonction du type d'IRA, ce qui explique possiblement leur sous-utilisation en pratique courante. Despite a great heterogeneity of clinical situations, the definition of acute kidney injury (AKI) is unique and its diagnosis includes an increase in serum creatinine and/or a decrease in diuresis. Contrary to the evolution of the biological markers of myocardial infarction observed for more than 50 years, it is always the "functional marker" creatinine which serves as the biological gold standard for the diagnosis of AKI. However, under the term of acute renal failure, very heterogeneous clinical situations are grouped together from an etiological, pathophysiological mechanisms, duration, evolution and associated complications. For fifteen/twenty years, new potential biomarkers have been studied and seem promising. Unlike troponin, which is increased in all types of myocardial infarction, these new biomarkers have different sensitivities and specificities depending on the type of AKI, which possibly explains their under-use in current practice. [ABSTRACT FROM AUTHOR]

Background: Activity and chronicity of kidney involvement in ANCA-associated vasculitis (AAV) can be currently reliably evaluated only by kidney biopsy. In this study, we measured a panel of serum and urinary biomarkers collected at the time of kidney biopsy and hypothesized that they could reflect specific histopathological parameters in the biopsy and help to predict prognosis. Methods: We examined a cohort of 45 patients with AAV and 10 healthy controls. Biomarker levels (DKK-3, CD163, EGF, PRO-C6 and C3M) were measured in this study by ELISA. Biopsies were scored with a scoring system for AAV (focal x crescentic x sclerotic x mixed class) and interstitial fibrosis was quantified. Results: Levels of urinary DKK-3, CD163, EGF, PRO-C6 and C3M significantly differed among biopsy classes in AAV, with urinary DKK-3 and PRO-C6 levels being highest in the sclerotic class and lowest in the focal class, urinary CD163 levels highest in the crescentic class and urinary C3M levels highest in the focal class. Moreover, the urinary biomarkers were able to discriminate focal biopsy class from the other classes. Urinary DKK-3, EGF, PRO-C6 and C3M levelsmeasured at the time of biopsy were also significantly related to the extent of fibrosis and to the final kidney function at the end of follow-up. Conclusions: This small pilot study suggests that selected urinary biomarkers of fibrosis and inflammation may reflect changes in the kidney biopsy and be prognostic of kidney outcome in patients with AAV. [ABSTRACT FROM AUTHOR]

The human Dickkopf (DKK) family includes four main secreted proteins, DKK-1, DKK-2, DKK-3, and DKK-4, as well as the DKK-3 related protein soggy (Sgy-1 or DKKL1). These glycoproteins play crucial roles in various biological processes, and especially modulation of the Wnt signaling pathway. DKK-3 is distinct, with its multifaceted roles in development, stem cell differentiation and tissue homeostasis. Intriguingly, DKK-3 appears to have immunomodulatory functions and a complex role in cancer, acting as either a tumor suppressor or an oncogene, depending on the context. DKK-3 is a promising diagnostic and therapeutic target that can be modulated by epigenetic reactivation, gene therapy and DKK-3-blocking agents. However, further research is needed to optimize DKK-3-based therapies. In this review, we comprehensively describe the known functions of DKK-3 and highlight the importance of context in understanding and exploiting its roles in health and disease.

BackgroundActivity and chronicity of kidney involvement in ANCA-associated vasculitis (AAV) can be currently reliably evaluated only by kidney biopsy. In this study, we measured a panel of serum and urinary biomarkers collected at the time of kidney biopsy and hypothesized that they could reflect specific histopathological parameters in the biopsy and help to predict prognosis.MethodsWe examined a cohort of 45 patients with AAV and 10 healthy controls. Biomarker levels (DKK-3, CD163, EGF, PRO-C6 and C3M) were measured in this study by ELISA. Biopsies were scored with a scoring system for AAV (focal x crescentic x sclerotic x mixed class) and interstitial fibrosis was quantified.ResultsLevels of urinary DKK-3, CD163, EGF, PRO-C6 and C3M significantly differed among biopsy classes in AAV, with urinary DKK-3 and PRO-C6 levels being highest in the sclerotic class and lowest in the focal class, urinary CD163 levels highest in the crescentic class and urinary C3M levels highest in the focal class. Moreover, the urinary biomarkers were able to discriminate focal biopsy class from the other classes. Urinary DKK-3, EGF, PRO-C6 and C3M levels measured at the time of biopsy were also significantly related to the extent of fibrosis and to the final kidney function at the end of follow-up.ConclusionsThis small pilot study suggests that selected urinary biomarkers of fibrosis and inflammation may reflect changes in the kidney biopsy and be prognostic of kidney outcome in patients with AAV.

This study will assess the safety and efficacy of the administration of adenoviral vector expressing the human-reduced expression in immortalized cells (Ad-REIC) to a liver tumor in patients with hepatocellular carcinoma (HCC) or liver metastasis of pancreatic cancer. A Phase I clinical study of Ad-REIC administration to a liver tumor in a patient with HCC or liver metastasis of pancreatic cancer will be conducted. The study is a single-arm, prospective, nonrandomized, noncomparative, open-label, single-center trial performed in Okayama University Hospital, Okayama, Japan. Ad-REIC will be injected into the liver tumor under ultrasound guidance. Ad-REIC administration will be repeated a total of three-times every 2 weeks. The primary end point is the dose-limiting toxicity and incidence of adverse events. The secondary end points are the objective response rate and disease control rate. This study aims to expand the indication of Ad-REIC by assessing its safety and efficacy in patients with HCC or liver metastasis of pancreatic cancer. [ABSTRACT FROM AUTHOR]

Skeletal muscle dysfunction is a critical finding in many respiratory diseases. However, a definitive biomarker to assess muscle decline in respiratory diseases is not known. We analyzed the association of plasma levels of glycoprotein Dickkopf-3 (Dkk-3), c-terminal agrin fragment-22 (CAF22) and microRNAs miR-21, miR-134a, miR-133 and miR-206 with hand-grip strength (HGS) and appendicular skeletal mass index (ASMI) in male, 54–73-year-old patients with chronic obstructive pulmonary diseases (COPD), asthma or pulmonary TB (n = 83–101/group). Patients with respiratory diseases showed a reduction in HGS and gait speed, while a reduction in ASMI was only found in patients with pulmonary TB. Among the sarcopenia indexes, HGS showed the strongest correlation with plasma CAF22, miR-21 and miR-206 levels while ASMI showed the strongest correlation with Dkk-3 and miR-133 in respiratory diseases. We found a modest-to-significant increase in the plasma markers of inflammation, oxidative stress and muscle damage, which had varying degrees of correlations with Dkk-3, CAF22 and selected micro RNAs (miRs) in respiratory diseases. Taken together, our data show that plasma levels of Dkk-3, CAF22 and selected miRs can be useful tools to assess accelerated sarcopenia phenotype in the elderly with respiratory diseases.

The human Dickkopf (DKK) family includes four main secreted proteins, DKK-1, DKK-2, DKK-3, and DKK-4, as well as the DKK-3 related protein soggy (Sgy-1 or DKKL1). These glycoproteins play crucial roles in various biological processes, and especially modulation of the Wnt signaling pathway. DKK-3 is distinct, with its multifaceted roles in development, stem cell differentiation and tissue homeostasis. Intriguingly, DKK-3 appears to have immunomodulatory functions and a complex role in cancer, acting as either a tumor suppressor or an oncogene, depending on the context. DKK-3 is a promising diagnostic and therapeutic target that can be modulated by epigenetic reactivation, gene therapy and DKK-3-blocking agents. However, further research is needed to optimize DKK-3-based therapies. In this review, we comprehensively describe the known functions of DKK-3 and highlight the importance of context in understanding and exploiting its roles in health and disease.

Meridianin C is a marine natural product known for its anti‐cancer activity. At present, the anti‐tumour effects of meridianin C on oral squamous cell carcinoma are unknown. Here, we investigated the effect of meridianin C on the proliferation of four different human tongue cancer cells, YD‐8, YD‐10B, YD‐38 and HSC‐3. Among the cells tested, meridianin C most strongly reduced the growth of YD‐10B cells; the most aggressive and tumorigenic of the cell lines tested. Strikingly, meridianin C induced a significant accumulation of macropinosomes in the YD‐10B cells; confirmed by the microscopic and TEM analysis as well as the entry of FITC‐dextran, which was sensitive to the macropinocytosis inhibitor amiloride. SEM data also revealed abundant long and thin membrane extensions that resemble lamellipodia on the surface of YD‐10B cells treated with meridianin C, pointing out that meridianin C‐induced macropinosomes was the result of macropinocytosis. In addition, meridianin C reduced cellular levels of Dickkopf‐related protein‐3 (DKK‐3), a known negative regulator of macropinocytosis. A role for DKK‐3 in regulating macropinocytosis in the YD‐10B cells was confirmed by siRNA knockdown of endogenous DKK‐3, which led to a partial accumulation of vacuoles and a reduction in cell proliferation, and by exogenous DKK‐3 overexpression, which resulted in a considerable inhibition of the meridianin C‐induced vacuole formation and decrease in cell survival. In summary, this is the first study reporting meridianin C has novel anti‐proliferative effects via macropinocytosis in the highly tumorigenic YD‐10B cell line and the effects are mediated in part through down‐regulation of DKK‐3. [ABSTRACT FROM AUTHOR]

We investigated the expression pattern of Dkk-3, a secreted Wnt pathway inhibitor, in mouse intestinal tissue and three-dimensional cultured Caco-2 spheroids. Dkk-3 was expressed at the bottom of crypts from the mouse small intestine. Human colon adenocarcinoma Caco-2 cells expressed Dkk-3 under a semi-confluent condition, but Dkk-3 expression was seen in only some of the Caco-2 cells when the cells were sparse. Caco-2 cells formed hollow spheroids in Matrigel, and the layer-forming cells in the hollow spheroids expressed Dkk-3. Our results demonstrated that Dkk-3 might affect intestinal cells when the fate of stem cells changes.

Background Dickkopf 3 (Dkk-3), a Wnt signaling inhibitor, is a characterized DKK family member that efficiently suppresses tumor growth in several types of cancer. Photodynamic therapy (PDT) is commonly used for treatment of different types of cancer and antitumor efficacy of PDT increased upon Wnt signaling inhibition. The objective of this study is to evaluate the effects of Dkk-3 and 5-aminolevulinic acid (5-ALA) mediated photodynamic therapy in breast cancer cell line. Material and methods 4T1 breast cell line were treated with either Dkk-3 (20, 40 and 80 ng/ml) 24 h followed by 5-ALA-PDT (1, 3 and 6 J/cm2). Also, 5-ALA was used at dose 1 mM. The apoptosis and post apoptotic necrosis were evaluated by FITC-Annexin-PI apoptosis detection kit. Results Obtained findings showed that both Dkk-3 and ALA-PDT have cytotoxic effects on cancer cells in a dose-dependent manner. The subtracted mean of death cell percentage in 20, 40 and 80 ng/ml of Dkk-3 were 6.8 ± 0.7%, 10.4 ± 0.84% and 16.1 ± 1.55% respectively. The subtracted mean of cell death induction in 5-ALA mediated PDT was 5.3 ± 0.77% at 6 J/cm2. Dkk-3 with ALA-PDT significantly increased cell death compared to either Dkk-3 or 5-ALA mediated PDT in cancer 4T1 cancer cell line (P ˂ 0.001). Conclusion In this study, observed results revealed that Dkk-3 induced the apoptosis in 4T1 breast cancer cells and apoptotic effects of Dkk-3 intensified following photodynamic therapy. This study provided a novel insight into the development of therapeutic strategies for treatment of breast cancer using Dkk-3 combined with PDT. [ABSTRACT FROM AUTHOR]

Objective. The objective of this study is to determine the efficiency of YKL-40, HE-4 and DKK-3 levels in early diagnosis of patients with endometrial cancer and in the pre-operative estimation of the prognostic parameters such as stage, grade and the extension of the disease. Methods. In this prospective study, 50 patients diagnosed with endometrial cancer and 50 women as a control group, who applied to Dokuz Eylul University and Ege University Faculties of Medicine, Obstetrics and Gynecology Clinics between May 2011-May 2012 were included. CA125, HE-4, YKL-40 and DKK-3 serum levels were measured by ELISA and compared between two groups. The relation between serum levels and histopathological results, extension of disease and prognostic factors were analyzed. Results. Preoperative serum CA125, HE-4 and YKL-40 levels were significantly higher in endometrial cancer group (p < 0.001). Serum HE-4 levels were significantly higher in advanced stages (p=0.004). When we examined early stage patients, YKL-40 levels were significantly higher in non-endometrioid histology compared with endometrioid adenocarcinoma (p=0.022). We also examined the relation between the markers and prognostic factors. Different from other markers, HE-4 levels were significantly higher in endometrial cancer patients who had lymphovascular space involvement, lower uterine segment involvement, endocervical stromal involvement, and deep myometrial invasion. Conclusion. YKL-40 and HE-4were significantly higher in patients with endometrial cancer. HE-4 seems to be superior to YKL-40 in discriminating early and advanced stages. Additionally, HE4 is significantly correlated with prognostic factors. HE-4 and YKL-40 may be successful in early determination of endometrial cancer and in detection of high risk subsets before surgery. [ABSTRACT FROM AUTHOR]

Wnt signaling plays crucial roles in regulation of a wide range of processes in different cell types including immune cells and, in particular, dendritic cells and T cells. Growing indications point out that Wnt pathway components modulate the both innate and adaptive immune responses through regulating DC functions. We investigated the effects of recombinant DKK-3 protein on the phenotype and biological functions of bone marrow-derived DCs (BM-DCs) as well as T cell polarization. The phenotype and the cytokine production of BM-derived DCs in the presence DKK-3 were analyzed using flow cytometry and ELISA, respectively. Also, capability of DCs to activate T cells was evaluated by CFSE-labeled splenocytes. Regulatory T cell induction, T cell polarization, and cytokine secretion were assessed by flow cytometry and ELISA in splenocytes cultured in the presence of DKK-3. Our results showed that the expression of CD86 and CD40 increased in the DKK-3-treated DC, while the expression of PDL-1 and PDL-2 diminished. Furthermore, the presence of DKK-3 decreased IL-10 and IL-4 production and increased IFN-gamma production by treated DCs.DKK-3. Moreover, DKK-3 shifted naive CD4 T cells towards TH1 cells through up-regulation of T-bet and down-regulation of GATA-3. Our results, therefore, suggest that DKK-3 protein has the ability to promote the generation of Th1-immunostimulatory DCs from its precursors. [ABSTRACT FROM PUBLISHER]

The Wnt/b-catenin signalling pathway is activated in pancreatic cancer initiation and progression. Dickkopf-related protein 3 (DKK3) is a member of the human Dickkopf family and an antagonist of Wnt ligand activity. However, the function of DKK3 in this pathway in pancreatic cancer is rarely known. We examined the expression of DKK3 in six human pancreatic cancer cell lines, 75 pancreatic cancer and 75 adjacent non-cancerous tissues. Dickkopf-related protein 3 was frequently silenced and methylation in pancreatic cancer cell lines (3/6). The expression of DKK3 was significantly lower in pancreatic cancer tissues than in adjacent normal pancreas tissues. Further, ectopic expression of DKK3 inhibits nuclear translocation of β-catenin induced by hypoxia in pancreatic cancer Bxpc-3 cell. The forced expression of DKK3 markedly suppressed migration and the stem cell-like phenotype of pancreatic cancer Bxpc-3 cell in hypoxic conditions through reversing epithelial- mesenchymal transition (EMT). The stable expression of DKK3 sensitizes pancreatic cancer Bxpc-3 cell to gemcitabine, delays tumour growth and augments gemcitabine therapeutic effect in pancreatic cancer xenotransplantation model. Thus, we conclude from our finding that DKK3 is a tumour suppressor and improved gemcitabine therapeutic effect through inducing apoptosis and regulating β-catenin/EMT signalling in pancreatic cancer Bxpc-3 cell. [ABSTRACT FROM AUTHOR]

In this study, we investigated a possible mechanism of β 2 -microglobulin (β2M) function in cancer metastases in vitro , using a human ovarian carcinoma cell line. β2M, a modulator acts as a cell growth-promoting and cellular signaling factors, was identified as a dickkopf-3 (DKK-3) interacting protein. We also observed that DKK-3 suppresses endothelial cell angiogenesis of β2M through vascular endothelial growth factor receptor-2 (VEGFR-2) in tumorigenesis. Luciferase activity was remarkably reduced by the transfection of DKK-3 in a dose-dependent manner. In addition, over-expression of β2M activates cell growth by suppressing DKK-3-induced apoptosis. The effect of β2M on cell cycle and apoptosis-regulatory components was also confirmed through the silencing of β2M expression. Furthermore, induction of β2M-mediated VEGFR-2/Akt/mTOR phosphorylation and tumor angiogenesis was significantly suppressed by over-expression of DKK-3. Taken together, our results suggest an underlying mechanism for an increase of β2M-related activity in ovarian tumor cells. [ABSTRACT FROM AUTHOR]

Amyloid-β (Aβ) is the most prominent protein in Alzheimer's disease ( AD) senile plaques. In addition, Aβ interacts with a variety of Aβ-associated proteins (AAPs), some of which can form complexes with Aβ and influence its clearance, aggregation or toxicity. Identification of novel AAPs may shed new light on the pathophysiology of AD and the metabolic fate of Aβ. In this study, we aimed to identify new AAPs by searching for proteins that may form soluble complexes with Aβ in CSF, using a proteomics approach. We identified the secreted Wnt pathway protein Dickkopf-related protein 3 (Dkk-3) as a potential Aβ-associated protein. Using immunohistochemistry on human AD brain tissue, we observed that (i) Dkk-3 co-localizes with Aβ in the brain, both in diffuse and classic plaques. (ii) Dkk-3 is expressed in neurons and in blood vessel walls in the brain and (iii) is secreted by leptomeningeal smooth muscle cells in vitro. Finally, measurements using ELISA revealed that (iv) Dkk-3 protein is abundantly present in both cerebrospinal fluid and serum, but its levels are similar in non-demented controls and patients with AD, Lewy body dementia, and frontotemporal dementia. Our study demonstrates that Dkk-3 is a hitherto unidentified Aβ-associated protein which, given its relatively high cerebral concentrations and co-localization with Aβ, is potentially involved in AD pathology. [ABSTRACT FROM AUTHOR]

Kremen-1 is a co-receptor of Wnt signaling, interacting with the Dkk-3 protein, which is an antagonist of the Wnt/p catenin pathway. In the present study we attempted to shed some light on the possible orientations of Kremen/Dkk-3 interactions, explaining the mechanisms of Kremen and Dkk-3 functions. Employing state-of-the-art software, a Kremen model was built and subsequently refined. The quality of the final model was evaluated using RMSD calculations. Ultimately, we used the Kremen model for docking analysis between Kremen and Dkk-3 molecules. A model built by the Robetta server showed the best quality scores. Near native coordination of the final model was verified getting < 2 Å RMSD values between our model and an experimentally resolved structure. Docking analysis indicates that one low energy orientation for Kremen/Dkk-3 involves all extracellular domains of Kremen, while another only involves the CUB and WSC domains. Kremen receptors may determine either antitumor or protumor effects of the Dkk protein. Based on existing reports and our findings, we hypothesized that there could be different cellular fate outcomes due to the orientation of Kremen and Dkk-3 interactions. One orientation of the Kremen/Dkk complex could lead to Kringle mediated antitumor effects, while another could end with CUB mediated protumor effects. [ABSTRACT FROM AUTHOR]

Wnt/β-catenin signaling pathway, having a crucial role in regulating diverse cellular processes, can be a new therapeutic target in cancer. To investigate the role of Dkk-1 (Dickkopf-1) and Dkk-3 in tumors and cirrhoses of the liver tissue in hepatocellular carcinoma (HCC), tissues from 38 patients with HCC resections including 5 patients who underwent hemangioma surgery of adjacent tumor tissues at the same time were obtained. Tissues were divided into three groups (nonfibrosis, cirrhosis, and carcinoma) through hematoxylin-eosin (HE) staining. Methylation-specific polymerase chain reaction (PCR) (MSP) measured the methylation status, and reverse transcription-PCR tested the messenger RNA (mRNA) levels, and immunohistochemical analysis provided levels of protein expression. The methylation detection rate of Dkk-1 and Dkk-3 was the highest ( P < 0.05) and the mRNA levels of Dkk-1 and Dkk-3 were the lowest ( P < 0.05) in the carcinoma tissues. The mRNA levels of β-catenin were significantly higher in the carcinoma tissue than the other tissues ( P < 0.05). The expression of Dkk-1 and Dkk-3 was significantly higher in the carcinoma tissues than the other tissues ( P < 0.05); but the β-catenin expression was the highest ( P < 0.05). Compared with the control, the mRNA levels of β-catenin in the Dkk-1 and Dkk-3 silencing cells increased 5.34 ( P < 0.05) and 3.5 times ( P > 0.05). After the interference of 5-aza-2′-deoxycytidine, the mRNA levels of Dkk-1 and Dkk-3 significantly increased 58.9 and 59.3 times ( P < 0.0001), and the mRNA levels of β-catenin decreased 6.02 times ( P < 0.05). In the process of HCC, the abnormal activity of Wnt/β-catenin signaling may be associated with the methylation of Dkk-1 and Dkk-3. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Ovarian cancer is the most lethal gynecological malignancy in North America. Although survival rates are high when the disease is diagnosed at an early stage, this decreases exponentially in late-stage diagnoses. As such, there is a need for novel early detection biomarkers. Through an integrated approach to ovarian cancer biomarker discovery that combines proteomics with transcriptomics and bioinformatics, our laboratory has identified folate-receptor 1 (FOLR1) and Dickkopf-related protein 3 (Dkk-3) as putative biomarkers. The objective of this study was to measure the levels of FOLR1 and Dkk-3 in the serum of patients with ovarian cancer, benign gynecological conditions and healthy women. Design and methods: FOLR1 and Dkk-3 were analyzed in serum of 100 ovarian cancer patients, 100 patients with benign gynecological conditions, and 100 healthy women using enzyme-linked immunosorbent assays (ELISAs). All specimens were analyzed in triplicate. Results: FOLR1 was significantly elevated in the serum of ovarian cancer patients compared to serum of both healthy controls (P<0.0001) and patients with benign gynecological conditions (P<0.0001). Furthermore, FOLR1 was strongly correlated with CA125 as both were elevated in the serous histotype and in late-stage disease. FOLR1 did not outperform CA125 in receiver operating characteristic curve analysis and there was no significant complementarity between the two markers. Dkk-3 was not significantly different between the three serum cohorts and was not correlated with CA125. Conclusions: FOLR1 is a new biomarker for ovarian cancer which correlates closely with CA125. The role of FOLR1 in the pathogenesis of ovarian cancer warrants further investigation. [Copyright &y& Elsevier]

Loss of tissue organization is a hallmark of the early stages of cancer, and there is considerable interest in proteins that maintain normal tissue architecture. Prostate epithelial cells cultured in Matrigel form three-dimensional acini that mimic aspects of prostate gland development. The organization of these structures requires the tumor suppressor Dickkopf-3 (Dkk-3), a divergent member of the Dkk family of secreted Wnt signalling antagonists that is frequently downregulated in prostate cancer. To gain further insight into the function of Dkk-3 in the prostate, we compared the prostates of Dkk3-null mice with those of control littermates. We found increased proliferation of prostate epithelial cells in the mutant mice and changes in prostate tissue organization. Consistent with these observations, cell proliferation was elevated in acini formed by human prostate epithelial cells stably silenced for Dkk-3. Silencing of Dkk-3 increased TGF-b/Smad signalling, and inhibitors of TGF-b/Smad signalling rescued the defective acinar phenotype caused by loss of Dkk-3. These findings suggest that Dkk-3 maintains the structural integrity of the prostate gland by limiting TGF-b/Smad signalling. [ABSTRACT FROM AUTHOR]

Dickkopf (Dkk)-3, an inhibitor of the Wnt/β-catenin pathway, is reported as a potential tumor suppressor gene in many cancers. To gain a better comprehension of the mechanisms involved in the carcinogenesis of oral squamous epithelium, protein expression and localization of Dkk-3 and β-catenin was investigated in normal epithelium, dysplasias and squamous cell carcinoma (SCC). An increase in β-catenin and Ki-67 expressions was observed from dysplasias to poorly differentiated SCC. Interestingly, an increase in Dkk-3 positive cells was also noted, which was correlated to the cancer progression step. A change in Dkk-3 localization during the transformation of normal oral epithelium to SCC was clearly observed. Dkk-3 was localized in the cell membrane in normal oral epithelium and in dysplasias, whereas that was localized in both cell membrane and cytoplasm in SCC. These results suggest that Dkk-3 is involved in the carcinogenesis of SCC with a distinct function from those in other cancers. [ABSTRACT FROM AUTHOR]

Abstract: REIC/Dkk-3 is a member of the Dickkopf family proteins known as Wnt-antagonists, and REIC/Dkk-3 expression is downregulated in a broad range of cancer types. REIC/Dkk-3 acts as a tumor suppressor in multiple cancer cell lines by inducing apoptosis through endoplasmic reticulum (ER) stress signaling. However, the intracellular interaction partners of REIC/Dkk-3 have not been fully elucidated. By employing yeast two-hybrid screening, we identified the human dynein light chain, Tctex-1, as a novel interaction partner of REIC/Dkk-3. We further disclosed that the interaction involves the 136–157 amino acid region of REIC/Dkk-3 by using the mammalian two-hybrid system. Interestingly, this binding region of REIC/Dkk-3 with Tctex-1 contains an amino acid sequence motif [-E-X-G-R-R-X-H-] which was previously reported as the Tctex-1 binding domain of dynein intermediate chain (DIC). Immunocytochemistry demonstrated that both REIC/Dkk-3 and Tctex-1 were localized around the ER of human fibroblasts, and the similar distribution pattern of the proteins suggests that their interaction occurs around the ER. This is the first study showing the interaction of a Dickkopf family protein with a dynein motor complex protein. The link between REIC/Dkk-3 and Tctex-1 may be of significance for understanding the molecular functions of the proteins in ER stress signaling and intracellular dynein motor dynamics, respectively. [Copyright &y& Elsevier]

Aim: The expression of Dkk-3, as a number of the Dkk family was different in different cancer. Because Dkk-3 encodes a secreted protein, we investigated whether the Dkk-3 protein is secreted into the sera of patients with gynecological cancer. Material & Methods: The levels of Dkk-3 protein were assessed by enzyme-linked immunosorbent assay in the sera of 104 patients with gynecological cancer: 36 with ovarian, 40 with cervical and 28 with endometrial cancers. Results: The serum levels of Dkk-3 protein in patients with ovarian cancer [25.54 (7.99) pg/mL] was lower than in normal individuals [42.08 (14.89) pg/mL] ( P = 0.000). But serum levels of Dkk-3 protein in patients with cervical [166.39 (300.68) pg/mL] ( P = 0.013) and endometrial cancers [73.64 (23.36) pg/mL] ( P = 0.000) were higher than in normal individuals. The serum levels of Dkk-3 protein were associated with clinical stage in patients with cervical and endometrial cancers. In patients with ovarian cancer, the serum levels of Dkk-3 protein were associated with lymphatic metastasis. In patients with cervical cancer, the serum levels of Dkk-3 protein were associated with tumor diameters. Conclusion: Dkk-3 protein detection using enzyme-linked immunosorbent assay as molecular markers can contribute to detection and diagnosis of gynecological cancer, especially for ovarian cancer and endometrial cancer. [ABSTRACT FROM AUTHOR]

We had previously reported that REIC/Dkk-3, a member of the Dickkopf (Dkk) gene family, works as a tumor suppressor. In this study, we evaluated the therapeutic effects of an intratumoral injection with adenoviral vector encoding REIC/Dkk-3 gene (Ad-REIC) using an orthotopic mouse prostate cancer model of RM-9 cells. We also investigated the in vivo anti-metastatic effect and in vitro anti-invasion effect of Ad-REIC gene delivery. We demonstrated that the Ad-REIC treatment inhibited prostate cancer growth and lymph node metastasis, and prolonged mice survival in the model. These therapeutic responses were consistent with the intratumoral apoptosis induction and in vitro suppression of cell invasion/migration with reduced matrix metalloprotease-2 activity. We thus concluded that in situ Ad-REIC/Dkk-3 gene transfer may be a promising therapeutic intervention modality for the treatment of prostate cancer.Cancer Gene Therapy (2007) 14, 765–772; doi:10.1038/sj.cgt.7701071; published online 29 June 2007 [ABSTRACT FROM AUTHOR]

Wnt signalling plays a critical role in the development of cancer. Recent studies indicate that Wnt signalling is negatively regulated by secreted Wnt antagonists such as secreted frizzled related proteins (sFRPs) and Dickkopfs (Dkks). We compared Dkk family expression levels in normal prostate and prostate cancer cells and found a reduction in Dkk-3 expression in cancer cells. Ectopic expression of Dkk-3 inhibited colony formation in LNCaP and PC3 prostate cancer cell lines and inducible expression of Dkk-3 reduced LNCaP cell proliferation. Moreover, small interfering RNA-mediated downregulation of Dkk-3 enhanced cell cycle progression in untransformed RWPE-1 prostate epithelial cells. Immunohistochemical analysis revealed that Dkk-3 is expressed in a subset of normal prostate gland acini and that Dkk-3 expression is reduced in prostate tumours, particularly those with a high Gleason grade, suggesting a role for Dkk-3 in postmitotic differentiation. Consistent with this, depletion of Dkk-3 disrupted acinar morphogenesis of RWPE-1 cells in a three-dimensional cell culture model. Our results are consistent with the loss of Dkk-3 expression resulting in impairment of glandular structure and uncontrolled prostate epithelial cell (PrEC) proliferation, both of which are crucial for prostate cancer progression.Oncogene (2006) 25, 6528–6537. doi:10.1038/sj.onc.1209661; published online 5 June 2006 [ABSTRACT FROM AUTHOR]

To identify putative tumor suppressor genes in hepatocarcinogenesis, we combined the representational difference analysis and reverse northern blot identifying downregulated genes in human hepatoma tissues. One of them was Dkk-3/REIC. Dkk-3/REIC was downregulated in 11 out of the 20 human hepatoma tissues as compared to their counterparts of noncancerous liver tissues by northern blot analysis. It was also downregulated in 29 out of 48 human cancer samples including the kidney, urinary bladder, prostate, pancreas and lung cancers. Its gene product, Dkk-3/REIC, was found to be N-glycosylated and have two isoforms, the 55?kDa in the cytosol and 50?kDa secreted in the medium. Ectopic expression of Dkk-3/REIC in HeLa, Hep3B and Huh 7 cells led to suppression of cell growth, which was primarily attributable to induction of cell apoptosis. The suppression phenomenon was found to be cell-type related (most prominent in HeLa and least in Hep3B cells) and cell-density dependent (attenuated as the cell density increased). Transduction of Dkk-3/REIC into HeLa and Hep3B cells caused suppression on colony formation in vitro and reduced tumor growth rate in inoculated athymic nude mice. In conclusion, these data indicate that Dkk-3/REIC functions as a suppressor for human tumor growth.Oncogene (2004) 23, 9183-9189. doi:10.1038/sj.onc.1208138 Published online 25 October 2004 [ABSTRACT FROM AUTHOR]

DKK-3: is a newly characterised mortalisation-related gene and an antagonist of the Wnt oncogenic signalling pathway whose expression is decreased in a variety of cancer cell lines, suggesting that the Dkk-3 gene, located at chromosome 11p15.1, functions as a tumour suppressor gene. Although 11p15 is a 'hot spot' for methylation in acute lymphoblastic leukaemia (ALL), the role of Dkk-3 abnormalities has never been evaluated in this disease. We analysed CpG island methylation of the Dkk-3 promoter in six ALL cell lines and 183 ALL patients. We observed Dkk-3 hypermethylation in all cell lines and in cells from 33% (60/183) of ALL patients. Moreover, Dkk-3 methylation was associated with decreased Dkk-3 mRNA expression and this expression was restored after exposure to the demethylating agent 5-AzaC. Clinical features did not differ between hypermethylated and unmethylated patients. Estimated disease-free survival (DFS) and overall survival at 10 and 11 years, respectively, were 49.8 and 45.6% for normal patients and 10.5 and 15.1% for hypermethylated patients (P=0.001 and 0.09). Multivariate analysis demonstrated that Dkk-3 methylation was an independent prognostic factor predicting DFS (P=0.0009). Our data suggest that Dkk-3 methylation occurs at an early stage in ALL pathogenesis and probably influences the clinical behaviour of the disease. [ABSTRACT FROM AUTHOR]

Background: Prostate cancer (PCa) is a frequent malignant tumor worldwide with high morbidity along with mortality. MicroRNAs (miRNAs) have been identified as key posttranscriptional modulators in diverse cancers. Herein, we purposed to explore the impacts of miR-363-3p on PCa growth, migration, infiltration along with apoptosis., Methods: The expressions of miR-363-3p along with Dickkopf 3 (DKK3) were assessed in clinical PCa specimens. We adopted the PCa cell line PC3 and transfected it using miR-363-3p repressors or mimic. The relationship of miR-363-3p with DKK3 was verified by a luciferase enzyme reporter assay. Cell viability along with apoptosis were determined by MTT assay coupled with flow cytometry analysis. Cell migration along infiltration were detected via wound healing, as well as Transwell assays. The contents of DKK3, E-cadherin, vimentin along with N-cadherin were analyzed via Western blotting accompanied with qRT-PCR., Results: MiR-363-3p was found to be inversely associated with the content of DKK3 in clinical PCa specimens. Further investigations revealed that DKK3 was miR-363-3p's direct target. Besides, overexpression of miR-363-3p decreased the contents of DKK3, promoted cell viability, migration coupled with infiltration, and reduced cell apoptosis, while silencing of miR-363-3p resulted in opposite influence. Upregulation of miR-363-3p diminished E-cadherin contents but increased vimentin along with N-cadherin protein contents in PC3 cells; in contrast, miR-363-3p downregulation produced the opposite result., Conclusion: Our study indicates that miR-363-3p promotes PCa growth, migration coupled with invasion while dampening apoptosis by targeting DKK3., (© 2022 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

Abstract Background Expression of Dkk-3, a secreted putative tumor suppressor, is altered in age-related proliferative disorders of the human prostate. We now investigated the suitability of Dkk-3 as a diagnostic biomarker for prostate cancer (PCa) in seminal plasma (SP). Methods SP samples were obtained from 81 patients prior to TRUS-guided prostate biopsies on the basis of elevated serum prostate-specific antigen (PSA; > 4 ng/mL) levels and/or abnormal digital rectal examination. A sensitive indirect immunoenzymometric assay for Dkk-3 was developed and characterized in detail. SP Dkk-3 and PSA levels were determined and normalized to total SP protein. The diagnostic accuracies of single markers including serum PSA and multivariate models to discriminate patients with positive (N = 40) and negative (N = 41) biopsy findings were investigated. Results Biopsy-confirmed PCa showed significantly higher SP Dkk-3 levels (100.9 ± 12.3 vs. 69.2 ± 9.4 fmol/mg; p = 0.026). Diagnostic accuracy (AUC) of SP Dkk-3 levels (0.633) was enhanced in multivariate models by including serum PSA (model A; AUC 0.658) or both, serum and SP PSA levels (model B; AUC 0.710). In a subpopulation with clinical follow-up > 3 years post-biopsy to ensure veracity of negative biopsy status (positive biopsy N = 21; negative biopsy N = 25) AUCs for SP Dkk-3, model A and B increased to 0.667, 0.724 and 0.777, respectively. Conclusions In multivariate models to detect PCa, inclusion of SP Dkk-3 levels, which were significantly elevated in biopsy-confirmed PCa patients, improved the diagnostic performance compared with serum PSA only.

Gastric cancer is a prevalent yet heterogeneous disease which ranks as the fifth most common cancer in the world. Dietary habit, genetic background, Helicobacter Pylori infections were the risk factors of gastric cancer. MicroRNA miR-425 is highly expressed in gastric cancer, but little attention has been devoted to the mechanism of miR-425 in tumorigenesis. This study aim to investigate the role of miR-425 in gastric cancer.The expression of miR-425 and Dickkopf-related protein-3(DKK-3) were analyzed by qRT-PCR. Gastric cell line BGC-823 and SGC-7901 were transfected miR-425 inhibitors or NC. Then, cell viability was determined by CCK-8, cell apoptosis and cell cycle were assessed by flow cytometer. Cell migration and cell invasion were analyzed by wound healing and trans-well assays. Luciferase reporter assay was conducted to assess the correlation between miR-425 and DKK-3. Downstream regulators, such as p-ASK1 and p-JNK, were analysis by western blot.Compared with normal gastric epithelium cell line, miR-425 was obviously upregulated in gastric cancer cell lines. MiR-425 inhibitor suppressed the cell viability, cell migration and cell invasion. The Luciferase assay data identified that DKK-3 is a target of miR-425. While miR-425 could lower the expression of DKK-3 which mediate tumorigenesis in a certain way.

-The tumor suppressor Dickkopf-3 (Dkk-3) is rather a unique molecule. Although it is related to the Dickkopf family of secreted Wnt antagonists, it does not directly inhibit Wnt signaling, and its function and mechanism of action are unknown. Endogenous Dkk-3 was recently found to be required to limit cell proliferation both in the developing mouse prostate and in 3D cultures of human prostate epithelial cells. Dkk-3 was further shown to modulate the response of normal prostate epithelial cells to transforming growth factor-β (TGF--β). These studies are consistent with a model in which Dkk-3 is required by normal cells to prevent the TGF--β switch from tumor suppressor to tumor promoter. Here, we discuss these findings and their potential impact on the development and progression of prostate cancer. [ABSTRACT FROM AUTHOR]

Among the causes of global death and disability, ischemic stroke (also known as cerebral ischemia) plays a pivotal role, by determining the highest number of worldwide mortality, behind cardiomyopathies, affecting 30 million people. The etiopathogenetic burden of a cerebrovascular accident could be brain ischemia (~80%) or intracranial hemorrhage (~20%). The most common site when ischemia occurs is the one is perfused by middle cerebral arteries. Worse prognosis and disablement consequent to brain damage occur in elderly patients or affected by neurological impairment, hypertension, dyslipidemia, and diabetes. Since, in the coming years, estimates predict an exponential increase of people who have diabetes, the disease mentioned above constitutes together with stroke a severe social and economic burden. In diabetic patients after an ischemic stroke, an exorbitant activation of inflammatory molecular pathways and ongoing inflammation is responsible for more severe brain injury and impairment, promoting the advancement of ischemic stroke and diabetes. Considering that the ominous prognosis of ischemic brain damage could by partially clarified by way of already known risk factors the auspice would be modifying poor outcome in the post-stroke phase detecting novel biomolecules associated with poor prognosis and targeting them for revolutionary therapeutic strategies. [ABSTRACT FROM AUTHOR]

Simple Summary: As we grow older, our muscles become smaller and weaker, a condition called sarcopenia. Several lung diseases can further worsen sarcopenia. Among them, COPD, asthma and tuberculosis are well-recognized causes of muscle loss. However, it is difficult and time-consuming to assess muscle health in elderly people with lung diseases. Here, we aimed to overcome this problem by measuring the blood levels of specific molecules that are related to muscle size and strength. We first show that elderly people with lung diseases have a greater degree of sarcopenia than healthy people. We then show that the blood levels of certain molecules (Dkk-3, CAF22, microRNAs) have varying degrees of associations with muscle size and strength in these patients. Thus, we propose that these molecules can be useful in assessing muscle health and the physical capacity of the elderly with lung diseases. Our findings have clinical applications since the quality and/or quantity of muscle tissues decide everyday lifestyle in the elderly, such as walking, lifting from chair and going to the bathroom etc. Skeletal muscle dysfunction is a critical finding in many respiratory diseases. However, a definitive biomarker to assess muscle decline in respiratory diseases is not known. We analyzed the association of plasma levels of glycoprotein Dickkopf-3 (Dkk-3), c-terminal agrin fragment-22 (CAF22) and microRNAs miR-21, miR-134a, miR-133 and miR-206 with hand-grip strength (HGS) and appendicular skeletal mass index (ASMI) in male, 54–73-year-old patients with chronic obstructive pulmonary diseases (COPD), asthma or pulmonary TB (n = 83–101/group). Patients with respiratory diseases showed a reduction in HGS and gait speed, while a reduction in ASMI was only found in patients with pulmonary TB. Among the sarcopenia indexes, HGS showed the strongest correlation with plasma CAF22, miR-21 and miR-206 levels while ASMI showed the strongest correlation with Dkk-3 and miR-133 in respiratory diseases. We found a modest-to-significant increase in the plasma markers of inflammation, oxidative stress and muscle damage, which had varying degrees of correlations with Dkk-3, CAF22 and selected micro RNAs (miRs) in respiratory diseases. Taken together, our data show that plasma levels of Dkk-3, CAF22 and selected miRs can be useful tools to assess accelerated sarcopenia phenotype in the elderly with respiratory diseases. [ABSTRACT FROM AUTHOR]

Background: Bladder cancer (BC) is a common malignancy with high morbidity and mortality. MicroRNAs (miRNAs) are critical post-transcriptional regulators in various cancers. This study aimed to investigate the effect of miR-425 on the migration and invasion of BC. Methods: The expression of miR-425 and Dickkopf 3 (DKK3) was examined in clinical BC specimens. T24 and 5637 BC cell lines were employed and transfected with miR-425 inhibitors. The correlation between miR-425 and DKK3 was determined by a luciferase reporter assay. Cell migration and invasion capacity were measured by wound healing and Transwell assays. The expression levels of DKK3, E-cadherin, N-cadherin and vimentin were analysed by Western blotting and qRT-PCR. Results: miR-425 was negatively correlated with the expression of DKK3 in clinical BC specimens. Further studies identified DKK-3 as a direct target of miR-425. Moreover, knockdown of miR-425 promoted the expression of DKK3 and suppressed cell migration and invasion capacity. miR-425 silencing increased E-cadherin levels but decreased vimentin and N-cadherin protein levels in T24 and 5637 cells. Conclusion: Our study indicated that miR-425 promoted the migration and invasion of BC via targeting DKK3., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Purpose: Glioblastomas are highly aggressive brain tumors. Various pathways are involved in gliomagenesis, among which the Wingless (Wnt) signaling. Dickkopf protein-related protein 3 (Dkk-3) interacts with proteins of Wnt pathwayas inhibitor. The Wnt signaling contributes to activity of the claudins, that are critical components of tight junctions, whose expression was altered selectively in cerebral microvessels of glioblastoma. The aim of this study was to determine the role of Wnt pathways in the regulation of tumor growth, apoptosis process by targeting Dkk-3, tight junctions alteration involving claudin-5, suggesting possible therapeutic interactions involving Wnt/Toll-like receptors (TLRs) pathways., Results: We showed a significant decreasing of Dkk-3 and claudin-5 in human glioblastoma cell lines, as well as in U-87 MG xenograft tumors and in glioblastoma human patient's tissues, with an involvement of the apoptosis process. Also, an interesting TLR-4/Wnt modulation highlighted that the absence of TLR-4 determined resistance to the tumor onset., Conclusions: We concluded that combined modulation of Wnt/Dkk-3/claudin-5 and TLR-4 pathways, simultaneously targeting apoptosis and survival signaling defects, might shift the balance from tumor growth stasis to cytotoxic therapeutic responses, flowing in greater therapeutic benefits., Methods: In the present study we investigated the expression of Dkk-3, claudin-5, apoptosis markers and TLR-4 receptor protein levels in in vitro studies on U-138MG, A-172, LN-18 and LN-229 human glioblastoma cell lines, and in vivo study using TLR-4 KO mice and in glioblastoma human patient's tissues., Competing Interests: CONFLICTS OF INTEREST The authors declare that they have no competing interests.

Background: The Dickkopf 3 (Dkk-3) protein is a member of the Dkk family known as Wnt signaling inhibitor. The level of DKk-3 changes in a wide range of cancers, such as colorectal cancer, lung cancer, prostate cancer, and bladder cancer, is proposed as a biomarker for diagnosis and prognosis of many cancers. The present study was conducted to evaluate the serum level of Dkk-3 as a cancer biomarker and to determine their prognostic value in colorectal cancer (CRC) patients and healthy matched controls. Methods: A total of 30 colorectal cancer patients at different stages of the disease and healthy matched controls with no history of inflammatory and autoimmune disease or cancer were enrolled in the study. The level of Dkk-3 was assessed serologically using enzymelinked immunosorbent assay (ELISA) method, moreover, relevance of these markers with patients' clinicopathological features was subsequently assessed. Means comparison and ROC curves analysis were done using SPSS software. P-value ˂0.05 was considered significant in all the tests. Results: In this study, it was revealed that serum level of Dkk-3 was significantly (p<0.001) lower in patients compared to the healthy controls. Statistical analysis showed that serum level of Dkk-3 has 78% specificity and 77% sensitivity (AUC= 0.782, 95% CI) for diagnosis of colorectal cancer. Conclusion: Dkk-3 protein can be considered as a potential biomarker for diagnosis and possibly the prognosis of colorectal cancer.