Higher Levels Of Dkk-1 Research Articles

Abstract 662: Local and systemic effects of Dickkopf-1 during breast cancer progression by limiting NK cell-mediated killing

Abstract While most breast cancer patients are diagnosed early, approximately 10-20% recur with the metastatic disease within 10 years. Unfortunately, cures are limited once recur, especially if the tumor spreads to the bone, a site resistant to therapies. Elevated levels of the Wnt inhibitor dickkopf-1 (Dkk1) are detected in breast cancer patients and correlate with the progression of bone metastases. We also find that breast cancer patients with progressive metastatic bone disease unresponsive to standard-of-care therapies have higher Dkk1 levels than patients with stable disease. Intriguingly, serum Dkk1 levels do not always correlate with Dkk1 expression in cancer cells. Thus, it is important to understand the source and role of Dkk1 in breast cancer. In this study, we used mice orthotopically injected with PyMT, EO771, and 4T1 breast cancer lines. Although Dkk1 was not expressed in the tumor cells, Dkk1 serum levels were upregulated in all models. To determine the role of Dkk1 in tumor progression, we used a Dkk1 neutralizing antibody (α-Dkk1) and found a significant reduction in primary tumor growth and in the bone of mice intratibially injected with PyMT tumor cells compared to IgG. To understand the source of Dkk1, we isolated the tumor mass and the bones from tumor-bearing mice. Dkk1 was highly expressed by the osteoblasts (OBs) in the bone and to a less extent by the cancer-associated fibroblasts (CAFs) in the tumor stroma. To address the role of bone- versus CAF-derived Dkk1, we generated mice with specific deletion of Dkk1 in the OBs (OsxCre;Dkk1fl/fl), or CAFs (Fsp1Cre;Dkk1fl/fl and aSMACreERT2;Dkk1fl/fl). To our surprise, all our mouse models showed a significant reduction in primary tumor growth, suggesting systemic and local effects of Dkk1. Further supporting direct local effects of Dkk1, WT mice co-injected with PyMT and Dkk1 deficient CAFs showed reduced tumor growth compared to mice co-injected with Dkk1 sufficient CAFs. To understand how Dkk1 exerts its pro-tumorigenic effects, we performed bulk RNAseq of tumor cells isolated from IgG and α-Dkk1 treated mice. To our surprise, we did not detect changes in pathways related to cell proliferation, survival, apoptosis, and cytoskeletal reorganization. However, pathways related to immune responses were upregulated in the α-Dkk1 treated tumors. Indeed, Dkk1 neutralization did not reduce tumor growth in the NSG immune-compromised mice. To investigate which immune population was targeted by Dkk1, we treated tumor-bearing mice with α-Dkk1 in combination with depletion of T, NK cells, or macrophages. Surprisingly, only NK cell depletion abrogated α-Dkk1 anti-tumor effects. In vitro assays further confirmed reduced NK cell killing efficiency against PyMT tumor cells in the presence of recombinant Dkk1. Our data show that Dkk1 exerts local and systemic effects to promote tumor progression by modulating the killing efficiency of NK cells. Citation Format: Seunghyun Lee, Biancamaria Ricci, Roberta Faccio. Local and systemic effects of Dickkopf-1 during breast cancer progression by limiting NK cell-mediated killing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 662.

Genetic analyses identify pleiotropy and causality for blood proteins and highlight Wnt/β-catenin signalling in migraine

Migraine is a common complex disorder with a significant polygenic SNP heritability ({h}_{{SNP}}^{2}). Here we utilise genome-wide association study (GWAS) summary statistics to study pleiotropy between blood proteins and migraine under the polygenic model. We estimate {h}_{{SNP}}^{2} for 4625 blood protein GWASs and identify 325 unique proteins with a significant {h}_{{SNP}}^{2} for use in subsequent genetic analyses. Pleiotropy analyses link 58 blood proteins to migraine risk at genome-wide, gene and/or single-nucleotide polymorphism levels—suggesting shared genetic influences or causal relationships. Notably, the identified proteins are largely distinct from migraine GWAS loci. We show that higher levels of DKK1 and PDGFB, and lower levels of FARS2, GSTA4 and CHIC2 proteins have a significant causal effect on migraine. The risk-increasing effect of DKK1 is particularly interesting—indicating a role for downregulation of β-catenin-dependent Wnt signalling in migraine risk, suggesting Wnt activators that restore Wnt/β-catenin signalling in brain could represent therapeutic tools against migraine.

Dickkopf 1 protein circulating levels as a possible biomarker of functional disability and chronic damage in patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) is an inflammatory disease characterized by joint destruction, deformity, lower functionality, and decrease in life expectancy. Wingless signaling pathway (Wnt) has been recently involved in bone homeostasis. Studies suggest that overexpression of the pathway inhibitors, like the Dickkopf 1 protein (DKK1), has been implicated in bone destruction. The objective of this study is to compare circulating levels of DKK1 in different groups of patients with disease activity (remission, low, moderate, high activity,) and functionality status. Three hundred seventy-nine patients with RA were evaluated between March 2015 and November 2016. Disease activity was evaluated by disease activity score 28 with C-reactive protein (DAS28CPR), simplified and clinical disease activity scores (SDAI, CDAI), routine assessment of patient index data 3 (RAPID3), functional status using Multidimensional Health Assessment Questionnaire (MD-HAQ), and the Steinbrocker functional classification. DKK1 levels were measured by ELISA. The mean age was 60.7± 13.9years. Disease duration was 13.2± 10.9years. Higher levels of DKK1 were not associated with disease activity by CDAI (p = 0.70), SDAI (p = 0.84), DAS28CRP (p = 0.80), or RAPID3 (p = 0.70). Interestingly higher levels of DKK1 were significantly associated to lower functional status evaluating by the Steinbrocker classification (p = 0,013), severe disability by MD-HAQ (p = 0,004), and variables associated with joint destruction like osteoporosis, higher titles of rheumatoid factor, smoking, and increased hospital admissions related to RA. Higher levels of DKK1 were found in patients with lower functional status. This association was not found in patients with greater disease activity by CDAI, SDAI, DAS28, and RAPID3. This could be explained by more structural damage; DKK1 could be used as a biomarker of joint destruction in RA.

OP0089 Genetic studies on DICKKOPF-1, sclerostin and the severity of joint destruction in rheumatoid arthritis

BackgroundInflammation in Rheumatoid Arthritis leads to impaired bone formation. The activity of the Wnt pathway influences osteoblast differentiation. Dickkopf-1 (Dkk1) and Sclerostin (Sost) are important negative regulators of bone formation,...

Comparison of Serum Dkk1 (Dickkopf-1) and Bone Mineral Density in Patients on Bisphosphonate Treatment Vs no Treatment

Complex pathways affect bone metabolism at the cellular level, and a balance between osteoblast and osteoclast activity is critical to bone remodeling. One of the major pathways affecting bone metabolism is Wnt/β-catenin signaling, and its disturbances lead to a wide range of bone abnormalities. An important antagonist of this pathway is Dickkopf-1 (Dkk1). Higher Dkk1 levels have been associated with increased bone loss due to inhibition of Wnt pathway. Currently, bisphosphonates are the most commonly used agents to treat primary osteoporotic patients. This study demonstrates the effect of bisphosphonates on Dkk1 levels and its correlation with bone mineral density (BMD). Eighty patients with low BMD were recruited and divided into 2 groups of 40 each (bisphosphonate treatment group and control group). The mean Dkk1 level in the treatment group was significantly reduced to 2358.18 vs 3749.80pg/mL in the control group (p<0.001). Pearson correlation coefficient showed negative correlation between Dkk1 and BMD at lumbar spine (r=−0.55) and femoral neck in the control group; however, no such correlation was found in the treatment group (r=−0.05). Hence, bisphosphonate therapy leads to reduction in Dkk1 levels, but it does not correlate with BMD in such patients.

Su1181 A Diagnostic DNA FISH Biomarker Assay Identifies HGD or EAC in Barrett Esophagus

examine the effect of acid on Wnt/β-catenin signaling activation and on regulating the expression of Dickkopf1 (DKK1), an inhibitor of the Wnt. Methods: Normal esophageal squamous cells lines (EPC1-hTERT, EPC2-hTERT), a non-dysplastic Barrett's esophageal cell line (CP-A) and an esophageal adenocarcinoma cell line (OE33) were exposed to acidic media (pH 4.0) in a pulsive manner. Human esophageal mucosal biopsies in triplicate from healthy (n=1), NERD (n=1), GERD (n=1) and Barrett's (n=1) patients were obtained and cultured in acidic (pH 4.0) or non acidic media. Localization and levels of β-catenin were determined by Immunofluorescence staining and Western blot. Wnt-activity was assessed by Luciferase assay following transfection with β-catenin-LEF/TCF-sensitive (TOP) or βcatenin-LEF/TCF insensitive (FOP) reporter vector. Immunofluorescence was used for βcatenin and E-Cadherin co-localization. DKK1 and β-catenin gene expression was resolved by qRT-PCR. DKK1 secretion in cells culture media and organ culture media was quantified by ELISA assay.Results: Acid destabilized E-cadherin/β-catenin complex in cell-cell junctions and resulted in β-catenin translocation to nucleus. Wnt-activity correlated with nuclear translocation of β-catenin. Cytosolic shuttling of β-catenin occurred in a rapid and transient manner after acid withdrawal. Chronic pulsed acid exposure increased DKK1 expression in normal squamous cells but not in metaplastic columnar cells. DKK1 overexpression correlated with a significant degradation of β-catenin. Mucosal biopsies from patients with NERD/ GERD secreted significantly higher levels of Dkk1 than healthy and metaplastic mucosa biopsies. Conclusions: These findings suggest that acid reflux induces the activation of Wnt-signaling pathway and that the overexpression of DKK1 is the long term response in the normal squamous esophageal tissue but not in the Barrett's esophagus. These findings also suggest a homeostatic role for DKK1 in GERD and its dysfunction to be a potential mechanism for progression to Barrett's metaplasia.

Dickkopf-1 as Potential Biomarker to Evaluate Bone Erosion in Systemic Lupus Erythematosus

This study aims to explore the potential role of circulating Dickkopf-1 (Dkk-1) and osteoprotegerin (OPG) in evaluating erosive arthritis in systemic lupus erythematosus (SLE). Serum Dkk-1 and OPG levels were examined in 130 SLE patients including eight with erosive arthritis, 100 rheumatoid arthritis (RA) patients and 50 healthy individuals by ELISA. Comparison of serum Dkk-1 levels with presence of anti-cyclic citrullinated peptides (CCP) antibodies in evaluating erosive arthritis in SLE was carried out. Associations of Dkk-1 and OPG levels with results of clinical examination were also noted. Dkk-1 levels were significantly increased in eight SLE patients with erosive arthritis, compared to 58 SLE patients with non-erosive arthritis, 64 SLE patients without arthritis, and healthy controls, while similar with RA. In contrast, no significant changes of OPG levels were found except for higher levels in RA. No differences were found in Dkk-1 levels of SLE patients with erosive arthritis subdivided according to presence or absence of anti-CCP antibodies. Moreover, higher levels of Dkk-1 were identified in anti-CCP positive SLE patients with erosive arthritis compared to those with non-erosive arthritis or without arthritis. However, no significant correlations between Dkk-1 and OPG levels or between Dkk-1 levels and other laboratory and clinical manifestations were observed. High levels of circulating Dkk-1 were associated with bone erosion in patients with SLE, even when anti-CCP antibodies were absent.

Levels of DKK1 in patients with acute myocardial infarction and response to atorvastatin

The Wnt-LPR5 signalling pathway plays an important role in skeletal homeostasis, especially in regulating osteoblastic activity. Activation of this pathway is regulated by various inhibitors, including DKK1. The objective of this study was to evaluate DKK1 levels in patients with ischemic heart disease, the response to atorvastatin and the relationship with bone mass. Twenty-one patients with acute myocardial infarction and twenty-three controls with a mean age of 61 ± 9 years with acute coronary syndrome were included. Patients were allocated to low (10-20mg) and high doses (40-80 mg) of atorvastatin according to baseline levels of cholesterol and triglycerides and the index of vascular risk. Patients were studied at hospital admission (baseline) and at 12 months of follow up. DKK1 was determined in all patients at baseline and at 12 months of follow up. Densitometric studies were conducted in the lumbar spine (L2-L4) and the femoral neck and trochanter using an X-ray densitometer. Patients had higher levels of DKK1 than controls, (111 ± 41 nmol/l versus 84 ± 27 nmol/l, p=0.014). Osteoporotic patients had higher levels of DKK1 (137.5 ± 33 nmol/l versus 95.4 ± 36 nmol/l, p=0.021). Analysis of the response to atorvastatin showed reduced DKK1 levels. In conclusion, in patients with acute coronary syndrome, atorvastatin decreases DKK1 levels. This may be a previously unreported mechanism of action of atorvastatin on bone, stimulating the Wnt signalling pathway and increasing bone mass.