Dickkopf-1 Research Articles

Characterization of cell states in biliary tract cancers identifies mechanisms of therapeutic resistance in a phase II trial of DKN-01/nivolumab.

Biliary tract cancers demonstrate profound therapeutic resistance, and broadly effective therapies for refractory disease are lacking. We conducted a single-arm, second-line phase II trial combining DKN-01, a humanized monoclonal antibody targeting Dickkopf-1 (DKK-1), and nivolumab to treat patients with advanced biliary tract cancer ( NCT04057365 ). No objective responses were seen. To identify mechanisms of treatment failure, we analyzed paired pre-treatment and on-treatment biopsies using scRNA-seq and constructed a detailed molecular classification of malignant and immune cells. We annotated five biliary tract cancer malignant cell states: classical, basal, mesenchymal, neural-like, and endothelial-like. Neural-like and endothelial-like states, which drive therapeutic resistance in other cancers, have not previously been described in BTC. Malignant cell states co-varied with distinct immune cell states, revealing diverse mechanisms of myeloid and T-cell mediated immune suppression, including M2 myeloid and terminally exhausted T cell programs that were induced by DKN-01/nivolumab. Here, we provide the first systematic classification of functionally annotated cell states in biliary tract cancer and provide new insight into resistance mechanisms to an immunotherapy combination that can inform the next generation of trials.

7881 Using Selective Estrogen Receptor Modulators to Reveal Therapeutic Vulnerabilities in ESR1 Mutant Breast Cancer

Abstract Disclosure: S.W. Fanning: Grant Recipient; Self; Olema Oncology. Hotspot activating somatic mutations to ESR1, the gene for estrogen receptor alpha (ER), enable hormone therapy resistance and drive breast cancer metastasis. The Y537S missense mutation within the ER ligand binding domain is the most activating, therapy resistant, and increases metastatic potential. Next generation antiestrogens including lasofoxifene (laso) and elacestrant (RAD1901) show improved progression-free survival over fulvestrant (fulv), but further progress is needed to achieve durable response. To fully address Y537S ESR1, it is critically important to understand how the mutation boosts metastasis. We have developed a small molecule antiestrogen, T6I-29, that uniquely impacts transcriptional pathways related to cell-cell adhesions and morphology. Two allele-specific phenotypes identified by the Oesterreich Laboratory enhance the metastasis of Y537S ESR1 breast cancer cells. T6I-29-specific pathway effects were driven by a significant downregulation of dickkopf-1 (DKK1), which was also observed but to a lesser extent with fulv, laso, and RAD1901. DKK1 is an immunosuppressive, tumor-secreted glycoprotein and its overexpression correlates with poor outcomes in multiple cancers. However, DKK1 acts as a tumor-suppressor in colorectal cancer, which does not rely on ER. Our preliminary studies suggest that DKK1 plays a role in ER+ breast cancer progression. We measured significantly elevated DKK1 protein levels in the blood plasma of 108 diverse ER+ breast cancer patients compared to 100 matched healthy female donors and levels increase coincident with tumor stage. Unfortunately, we lack ESR1 mutation status and other critical details to make further insights on these patients. DKK1 gene expression and protein secretion is stimulated in WT cells by the pathogenic hormone 17β-estradiol (E2), while it is constitutively expressed in Y537S ESR1 cells. DKK1 is characterized as a WNT antagonist but can also induce PI3K/Akt signaling. Interestingly, DKK1 is elevated and ERα responsive in WT not mutant PI3KCA cell lines. DKK1 knockdown also reduced proliferation of Y537S ESR1 breast cancer cells where elevated DKK1 was observed. Presentation: 6/3/2024

DKN-01 Suppresses Gastric Cancer Progression Through Activating cGAS-STING Pathway to Block Macrophage M2 Polarization.

Dickkopf-1 (DKK1) is a secretory antagonist that can bind with the Wnt coreceptor to desensitize cells to canonical Wnt ligands. DKN-01 is a specific antibody targeting secreted DKK1, which has been investigated as a monotherapy or combination therapy for various malignant tumors, including gastric cancer (GC). Tumor-associated macrophages (TAMs) with high plasticity usually present M2 phenotype, which can promote tumor progression. The aim of this study was to investigate the effect of DKN-01 on macrophage polarization in GC and the underlying molecular mechanism. To ascertain the effect of DKN-01 on GC tumor growth, we established a tumor-bearing mouse model and found that DKN-01 treatment suppressed tumor growth efficiently. Through RNA-seq and pathway enrichment analysis, we identified that the differentially expressed genes after DKN-01 treatment are associated with tumor immune-related pathways. Macrophage polarization was assessed using immunohistochemistry and quantitative real-time polymerase chain reaction. DKN-01 and knockdown of DKK1 promoted M1 polarization and inhibited M2 polarization of macrophages, while DKK1 overexpression got the opposite results. Moreover, DKN-01 activated the cGAS/STING pathway, while the inactivation of cGAS-STING pathway using RU.521 reversed the inhibition of tumor growth in vivo and macrophage M2 polarization caused by DKN-01. This study reveals that DKN-01 suppresses GC tumor growth through activating cGAS-STING pathway to block macrophage M2 polarization.

Newly developed humanized anti-CKAP4 antibody suppresses pancreatic cancer growth by inhibiting DKK1-CKAP4 signaling.

Cytoskeleton-associated protein 4 (CKAP4) is a cell surface receptor for Dickkopf 1 (DKK1), a secreted protein. The DKK1-CKAP4 pathway is activated in various malignant tumors, including pancreatic, lung, esophageal, and liver cancers, to promote tumor growth. Thus, CKAP4 has been expected to represent a novel molecular target of cancer therapy. Recombinant mouse anti-CKAP4 antibodies were generated based on an original mouse antibody (3F11-2B10) and inhibited DKK1-CKAP4 signaling and xenograft tumor formation induced by pancreatic cancer cells, which was comparable with 3F11-2B10. From the 3F11-2B10 nucleotide sequence, humanized anti-CKAP4 antibody (Hv1Lt1) was subsequently developed. The binding affinity of Hv1Lt1 for CKAP4 was superior to that of 3F11-2B10. Hv1Lt1 inhibited DKK1 binding to CKAP4, AKT activity, and sphere formation of pancreatic cancer cells, which was comparable with 3F11-2B10. Hv1Lt1 also suppressed xenograft tumor formation induced by human pancreatic cancer cells and tumor growth in murine cancer models, in which murine pancreatic cancer organoids were orthotopically transplanted into the pancreas. In resected tumor samples from mice treated with Hv1Lt1, anti-tumor immune reactions were modulated and cytotoxic T cells were highly infiltrated in the tumor microenvironment. Additionally, combination of Hv1Lt1 and other chemotherapy drugs exhibited stronger effects compared with monotherapy. These results suggest that Hv1Lt1 represents a promising anti-cancer therapy.

Hair Growth-Promoting Effect of Hydrangea serrata (Thunb.) Ser. Extract and Its Active Component Hydrangenol: In Vitro and In Vivo Study.

With the escalating prevalence of hair loss, the demand for effective hair loss treatment has surged. This study evaluated the effects of hot water extract of Hydrangea serrata (Thunb.) Ser. leaf (WHS) on hair growth, employing cell cultures, mice, and human skin organoid models. Both WHS and hydrangenol were found to enhance 5α-reductase inhibitory activity. WHS and hydrangenol have been shown to stimulate dermal papilla cell (DPC) growth, potentially through factors like keratinocyte growth factor (KGF), fibroblast growth factor 10 (FGF10), and transforming growth factor-β1 (TGF-β1). They also elevated the expression levels of keratin genes (K31 and K85) and the ceramide synthase (CerS3) gene, crucial clinical indicators of hair health. Furthermore, they exhibited notable anti-inflammatory and anti-androgenic properties by reducing the levels of tumor necrosis factor-α (TNF-α) and androgen signaling molecules, including androgen receptor (AR) and dickkopf-1 (DKK-1) gene expression. Oral administration of WHS to C57BL/6 mice for 3 weeks confirmed its hair growth-promoting effects, improving hair growth parameters and gene expression without significant changes in hair weight. Additionally, in a human skin organoid model, WHS was found to stimulate hair formation and augment the expression of follicle markers. These findings position WHS as a promising nutraceutical for promoting hair health, as evidenced by its efficacy in both in vitro and in vivo models.

Enhanced Association of Novel Cardiovascular Biomarkers Fetuin-A and Catestatin with Serological and Inflammatory Markers in Rheumatoid Arthritis Patients.

Rheumatoid arthritis (RA) is a chronic autoimmune disease associated with increased cardiovascular disease (CVD) risk and mortality. This work aimed to evaluate the serum levels of the novel CV biomarkers fetuin-A (fet-A), Dickkopf-1 (DKK-1), galectin-3 (Gal-3), interleukin-32 (IL-32), and catestatin (CST) in RA patients and their associations with RA parameters and CVD markers. A cohort of 199 RA patients was assessed for traditional CVD risk factors, RA disease activity, and biomarker levels. Carotid ultrasound was used to measure carotid intima-media thickness (cIMT) and carotid plaque presence (cPP). Multivariate analyses examined correlations between biomarkers and RA parameters, serological markers, and CVD markers. Adjusted models showed that elevated CST expression levels were associated with rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA) positivity (OR = 2.45, p = 0.0001 and OR = 1.48, p = 0.04, respectively) in the overall cohort and for RF in men and women, respectively. In addition, fet-A concentration was inversely associated with the erythrocyte sedimentation rate (ESR) in the overall cohort (β = -0.15, p = 0.038) and in women (β = -0.25, p = 0.004). Fet-A levels were also negatively correlated with disease activity (DAS28-ESR) scores (β = -0.29, p = 0.01) and fibrinogen concentration (β = -0.22, p = 0.01) in women. No adjusted associations were observed for Gal-3, DKK-1 or IL32 concentration. The study revealed no significant associations between the biomarkers and cIMT or cPP. The measurement of CST and fet-A levels could enhance RA patient management and prognosis. However, the utility of biomarkers for evaluating CV risk via traditional surrogate markers is limited, highlighting the need for continued investigations into their roles in RA.

Ablation of LRP6 in alpha-smooth muscle actin-expressing cells abrogates lung inflammation and fibrosis upon bleomycin-induced lung injury.

Low-density lipoprotein receptor-related protein 6 (LRP6) is a receptor for Wnt ligands. Tissue fibrosis is a progressive pathological process with excessive extracellular matrix proteins (ECM) deposition. Myofibroblasts, identified by alpha-smooth muscle actin (αSMA) expression, play an important role in tissue fibrosis by producing ECM production. Here we found that Wnt antagonist Dickkopf1 (DKK1) induced gene expressions associated with inflammation and fibrosis in lung fibroblasts. We demonstrated that genetic deletion of LRP6 in αSMA-expressing cells using Acta2 -cre Lrp6 fl/fl ( Lrp6 AKO ) mice abrogated bleomycin (BLM)-induced lung inflammation and fibrosis phenotype, suggesting an important role of LRP6 in modulating inflammation and fibrotic processes in the lung. Our results highlight the crucial role of LRP6 in fibroblasts in regulating inflammation and fibrosis upon BLM-induced lung injury.

Associations of serum Dickkopf-1 levels with disease severity and 90-day Prognosis after spontaneous intracerebral hemorrhage: results from the prospective cohort study.

Dickkopf-1 (DKK-1) may be involved in inflammatory response and secondary brain injury after acute brain injury. We gauged serum DKK-1 levels and further assessed its correlation with disease severity and investigated its predictive value for 90-day prognosis in patients with spontaneous intracerebral hemorrhage (sICH). Serum DKK-1 levels were measured in 128 sICH patients and 128 healthy controls. The severity of sICH was assessed using the Glasgow Coma Scale (GCS) scores and hematoma volumes. Poor prognosis was referred to as a Glasgow Outcome Scale (GOS) score of 1-3 at 90days after stroke. Multivariate analysis was performed to identify associations of serum DKK-1 levels with disease severity, early neurological deterioration (END) and poor prognosis. Receiver operating characteristic curve (ROC) was built to investigate the prognostic predictive capability. The serum DKK-1 levels of patients were significantly higher than those of controls (median, 4.74ng/mL versus 1.98ng/mL; P < 0.001), and were independently correlated with hematoma volumes (ρ = 0.567, P < 0.001; t = 3.444, P = 0.001) and GCS score (ρ = -0.612, P < 0.001; t = -2.048, P = 0.043). Serum DKK-1 significantly differentiated patients at risk of END (area under ROC curve (AUC), 0.850; 95% confidence interval (CI), 0.777-0.907; P < 0.001) and poor prognosis (AUC, 0.830; 95% CI, 0.753-0.890; P < 0.001), which had similar prognostic ability, as compared to GCS scores and hematoma volumes. Subsequent Logistic regression model affirmed that GCS score, hematoma volume, and serum DKK-1 levels were independently associated with END and poor prognosis at 90days after sICH. The models, which contained them, performed well using ROC curve analysis and calibration curve analysis. Serum DKK-1 levels are markedly associated with disease severity, END and 90-day poor prognosis in sICH. Hence, serum DKK-1 is presumed to be used as a potential prognostic biomarker of sICH.

Knockdown of WISP1/DKK1 restrains phenotypic plasticity in esophageal squamous cell carcinoma by suppressing epithelial-mesenchymal transition and stemness.

Wnt-induced signaling protein 1 (WISP1) and Dickkopf-1 (DKK1) are highly expressed in esophageal squamous cell carcinoma (ESCC), but no direct connection was identified between them. Phenotypic plasticity is a hallmark of ESCC. This research intended to identify the association between WISP1 and DKK1 and their roles in the phenotypic plasticity of ESCC. Genes differentially expressed in esophageal carcinoma were analyzed in the GEO database, followed by analyses of GO and KEGG enrichment to screen the hub gene. WISP1 expression and DKK1 secretion was assessed in ESCC tissues and cells. The tumor xenograft and in vivo metastasis models were established by injecting ESCC cells into nude mice. Functional deficiency and rescue experiments were conducted, followed by assays for cell proliferation, migration/invasion, stemness, epithelial-mesenchymal transition (EMT), and apoptosis, as well as tumor volume, weight, proliferation, stemness, and lung metastasis. The binding relationship and co-expression of WISP1 and DKK1 were determined. WISP1 and DKK1 were upregulated in ESCC cells and tissues, and WISP1 was enriched in the cell stemness and Wnt pathways. WISP1 knockdown subdued proliferation, migration/invasion, EMT activity, and stemness but enhanced apoptosis in ESCC cells. WISP1 knockdown restrained ESCC growth, proliferation, stemness, and metastasis in vivo. WISP1 bound to DKK1 in ESCC. DKK1 overexpression abolished the repressive impacts of WISP1 knockdown on the malignant behaviors of ESCC cells in vitro and of ESCC tumor in vivo. Knockdown of WISP1/DKK1 restrains the phenotypic plasticity in esophageal squamous cell carcinoma by suppressing epithelial-mesenchymal transition and stemness.

EZH2-H3K27me3-Mediated Epigenetic Silencing of DKK1 Induces Nucleus Pulposus Cell Pyroptosis in Intervertebral Disc Degeneration by Activating NLRP3 and NAIP/NLRC4.

Nucleus pulposus (NP) cell pyroptosis is crucial for intervertebral disc degeneration (IDD). However, the precise mechanisms underlying pyroptosis in IDD remain elusive. Therefore, this study aimed to investigate how dickkopf-1 (DKK1) influences NP cell pyroptosis and delineate the regulatory mechanisms of IDD. Behavioral tests and histological examinations were conducted in rat IDD models to assess the effect of DKK1 on the structure and function of intervertebral discs. Detected pyroptosis levels using Hoechst 33,342/propidium iodide (PI) double staining, and determined pyroptosis-related protein expression via western blotting. The cellular mechanisms of DKK1 in pyroptosis were explored in interleukin (IL)-1β-induced NP cells transfected with or without DKK1 overexpression plasmids (oe-DKK1). In addition, IL-1β-treated NP cells transfected with sh-EZH2 and/or sh-DKK1 were utilized to clarify the interplay between the enhancer of zeste homologue 2 (EZH2) and DKK1 in pyroptosis. Additionally, the epigenetic regulation of DKK1 by EZH2 was explored in NP cells treated with the EZH2 inhibitors GSK126/DZNep. DKK1 expression decreased in IDD rats. Transfection with oe-DKK1 reduced pro-inflammatory factors and extracellular matrix markers in IDD rats. In IL-1β-induced NP cells, DKK1 overexpression suppressed pyroptosis and inhibited the NLRP3 and NAIP/NLRC4 inflammasome activation. EZH2 knockdown increased DKK1 expression and reduced pyroptosis-related proteins. Conversely, DKK1 downregulation reversed the inhibitory effects of EZH2 knockdown on pyroptosis. Furthermore, EZH2 suppressed DKK1 expression via H3K27 methylation at the DKK1 promoter. EZH2 negatively regulates DKK1 expression via H3K27me3 methylation, promoting NP cell pyroptosis in IDD patients. This regulatory effect involves the activation of NLRP3 and NAIP/NLRC4 inflammasomes.

The Inhibition of Oxidative Stress-Mediated Cell Apoptosis by the Caspase Inhibitor (S)-3-((S)-2-(6-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-1-oxoisoindolin-2-yl)butanamido)-4-oxo-5-(2,3,5,6-tetrafluorophenoxy)pentanoic Acid in Human Dermal Papilla Cells

Alopecia is traditionally viewed as androgen-dependent, but emerging evidence has implicated oxidative stress in the pathogenesis of hair loss. Current treatments for alopecia have limited efficacy, leading to the need for new therapies. Human dermal papilla cells (hDPCs) play a pivotal role in hair follicle (HF) development and hair growth regulation. In this study, we investigated the potential of (S)-3-((S)-2-(6-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-1-oxoisoindolin-2-yl)butanamido)-4-oxo-5-(2,3,5,6 tetrafluorophenoxy) pentanoic acid (THPA), a pan-caspase inhibitor, to reduce ROS-induced cellular damage and apoptosis in hDPCs. Our study revealed that THPA effectively suppressed hydrogen peroxide-induced apoptosis while also attenuating activated caspase signaling. Additionally, THPA restored the down-regulated expression of β-catenin, a key mediator of the Wnt/β-catenin pathway, in hDPCs exposed to hydrogen peroxide. Furthermore, significant alterations in Akt/mTOR/p70S6K signaling were observed following THPA treatment. Notably, THPA treatment led to a reduction in the expression of Dickkopf-1 (DKK-1), an inhibitor of the Wnt/β-catenin pathway implicated in hair follicle regression. Moreover, THPA treatment decreased the expression of the cell senescence markers p21 and p16, suggesting a potential role in preserving hDPC function and delaying hair follicle regression. Collectively, our findings highlight the therapeutic potential of THPA in preventing hair loss by protecting hDPCs against oxidative stress damage.

The Role of Serum Dickkopf1 and CKAP4 Levels in Diagnosing Colorectal Cancer and Measuring the Disease Severity: A Prospective Study.

Background and Objective: Colorectal cancer (CRC) is among the most common types of cancer. Although the disease is treatable in its early stages, five-year survival falls below 20% in the later stages. CEA and CA19-9 are tumor markers used in the diagnosis and follow-up of the disease in clinical practice; however, their diagnostic effectiveness is insufficient. Therefore, the identification of biomarkers that can be easily studied from serum and can diagnose CRC and determine its severity is highly important. In this context, dickkopf1 (DKK1) and cytoskeleton-associated protein 4 (CKAP4) are both promising biomarkers. Materials and Methods: Serum DKK1 and CKAP4 levels were measured in 55 patients with CRC and 40 healthy controls. The patients with CRC were divided into groups based on pathological stages and histological differentiation. The serum levels of both proteins in patients with CRC were measured preoperatively and 10 and 30 days postoperatively. Results: Serum DKK1 and CKAP4 were significantly higher in the CRC group than in the healthy controls (p < 0.05). Serum levels of both proteins rose in line with the disease stage and grade but decreased following surgical resection. A positive correlation was observed between tumor diameter and protein blood levels. The diagnostic efficacy of DKK1 and CKAP4 in CRC (approximately 95%) was higher than that of markers such as CEA and CA19-9. Conclusions: The DKK1 and CKAP4 serum values of patients with CRC are promising biomarkers. They can potentially be used in CRC management, namely, in the diagnosis and treatment of tumor response access and in tumor aggressiveness prediction.

Effect of Hypoglycemia and Rebound Hyperglycemia on Proteomic Cardiovascular Risk Biomarkers.

Introduction: Hypoglycemia has been associated with cardiovascular events, and glucose variability has been suggested to be associated with increased cardiovascular risk. Therefore, in this study, we examined the effect on proteomic cardiovascular risk protein markers of (i) mild iatrogenic hypoglycemia and (ii) severe iatrogenic hypoglycemia followed by rebound hyperglycemia. Methods: Two iatrogenic hypoglycemia studies were compared; firstly, mild hypoglycemia in 18 subjects (10 type 2 diabetes (T2D), 8 controls; blood glucose to 2.8 mmoL/L (50 mg/dL) for 1 h), and secondly, severe hypoglycemia in 46 subjects (23 T2D, 23 controls; blood glucose to <2.2 mmoL/L (<40 mg/dL) transiently followed by intravenous glucose reversal giving rebound hyperglycemia). A SOMAscan assay was used to measure 54 of the 92 cardiovascular protein biomarkers that reflect biomarkers involved in inflammation, cellular metabolic processes, cell adhesion, and immune response and complement activation. Results: Baseline to euglycemia showed no change in any of the proteins measured in the T2D cohort. With severe hypoglycemia, the study controls showed an increase in Angiopoietin 1 (ANGPT1) (p < 0.01) and Dickkopf-1 (DKK1) (p < 0.01), but no changes were seen with mild hypoglycemia. In both the mild and severe hypoglycemia studies, at the point of hypoglycemia, T2D subjects showed suppression of Brother of CDO (BOC) (p < 0.01). At 1 h post-hypoglycemia, the changes in ANGPT1, DKK1, and BOC had resolved, with no additional protein biomarker changes despite rebound hyperglycemia from 1.8 ± 0.1 to 12.2 ± 2.0 mmol/L. Conclusions: Proteomic biomarkers of cardiovascular disease showed changes at hypoglycemia that resolved within 1 h following the hypoglycemic event and with no changes following hyperglycemia rebound, suggesting that any cardiovascular risk increase is due to the hypoglycemia and not due to glucose fluctuation per se.

Dickkopf-1 (DKK1) drives growth and metastases in castration-resistant prostate cancer.

Metastatic castration-resistant prostate cancer (mCRPC) is associated with a poor prognosis and remains an incurable fatal disease. Therefore, the identification of molecular markers involved in cancer progression is urgently needed to develop more-effective therapies. The present study investigated the role of the Wnt signaling modulator Dickkopf-1 (DKK1) in the growth and metastatic progression of mCRPC. DKK1 silencing through siRNA and deletion via CRISPR/Cas9 editing were performed in two different metastatic castration-resistant prostate cancer cell lines (PC3 and DU145). A xenograft tumor model was used to assess tumor growth and metastases. In in vitro experiments, both DKK1 silencing and deletion reduced cell growth and migration of both cell lines. DKK1 knockout clones (DKK1-KO) exhibited cell cycle arrest, tubulin reorganization, and modulation of tumor metastasis-associated genes. Furthermore, in DKK1-KO cells, E-cadherin re-expression and its membrane co-localization with β-catenin were observed, contributing to reduced migration; Cadherin-11, known to increase during epithelial-mesenchymal transition, was down-regulated in DKK1-KO cells. In the xenograft mouse model, DKK1 deletion not only reduced tumor growth but also inhibited the formation of lung metastases. In conclusion, our findings support the key role of DKK1 in the growth and metastatic dissemination of mCRPC, both in vitro and in vivo.

YAP prevents senescence of dermal fibroblast and inhibits melanogenesis via paracrine effect of DKK1.

Senile skin hyperpigmentation displays remarkable histopathological features of dermal aging. The crosstalk between melanocytes and dermal fibroblasts plays crucial roles in aging-related pigmentation. While senescent fibroblasts can upregulate pro-melanogenic factors, the role of anti-melanogenic factors, such as dickkopf1 (DKK1), and the upstream regulatory mechanism during aging remain obscure. This study investigated the roles of yes-associated protein (YAP) and DKK1 in the regulation of dermal fibroblast senescence and melanogenesis. Our findings demonstrated decreased YAP activity and DKK1 levels in intrinsic and extrinsic senescent fibroblasts. YAP depletion induced fibroblast senescence and downregulated the expression and secretion of DKK1, whereas YAP overexpression partially reversed the effect. The transcriptional regulation of DKK1 by YAP was supported by dual-luciferase reporter and chromatin immunoprecipitation assays. Moreover, YAP depletion in fibroblasts upregulated Wnt/β-catenin in melanocytes and stimulated melanogenesis, which was partially rescued by the re-supplementation of DKK1. Conversely, overexpression of YAP in senescent fibroblasts decreased Wnt/β-catenin levels in melanocytes and inhibited melanogenesis. Additionally, reduced levels of YAP and DKK1 were verified in the dermis of solar lentigines. These findings suggest that, during skin aging, epidermal pigmentation may be influenced by YAP in the dermal microenvironment via the paracrine effect of DKK1.

Pathogenesis of Alopecia Areata and Vitiligo: Commonalities and Differences.

Both alopecia areata (AA) and vitiligo are distinct, heterogenous, and complex disease entities, characterized by nonscarring scalp terminal hair loss and skin pigment loss, respectively. In AA, inflammatory cell infiltrates are in the deep reticular dermis close to the hair bulb (swarm of bees), whereas in vitiligo the inflammatory infiltrates are in the epidermis and papillary dermis. Immune privilege collapse has been extensively investigated in AA pathogenesis, including the suppression of immunomodulatory factors (e.g., transforming growth factor-β (TGF-β), programmed death-ligand 1 (PDL1), interleukin-10 (IL-10), α-melanocyte-stimulating hormone (α-MSH), and macrophage migration inhibitory factor (MIF)) and enhanced expression of the major histocompatibility complex (MHC) throughout hair follicles. However, immune privilege collapse in vitiligo remains less explored. Both AA and vitiligo are autoimmune diseases that share commonalities in pathogenesis, including the involvement of plasmacytoid dendritic cells (and interferon-α (IFN- α) signaling pathways) and cytotoxic CD8+ T lymphocytes (and activated IFN-γ signaling pathways). Blood chemokine C-X-C motif ligand 9 (CXCL9) and CXCL10 are elevated in both diseases. Common factors that contribute to AA and vitiligo include oxidative stress, autophagy, type 2 cytokines, and the Wnt/β-catenin pathway (e.g., dickkopf 1 (DKK1)). Here, we summarize the commonalities and differences between AA and vitiligo, focusing on their pathogenesis.

High dose statin treatment reduces circulating Dickkopf-1 following acute myocardial infarction

BackgroundSecreted glycoproteins of the Dickkopf (DKK) family modify Wnt signaling and may influence plaque destabilization but their modulation by statins in MI patients is not known. MethodsWe measured plasma DKK-1 and DKK-3 in patients with acute ST-segment elevation MI (STEMI) before percutaneous coronary intervention (PCI) and after 2 and 7 days and 2 months in patients receiving short-term high-dose (40 mg rosuvastatin, given before PCI; n = 25) and moderate dose (20 mg simvastatin, given the day after PCI; n = 34). In vitro modulation of DKK-1 in human umbilical vein endothelial cells (HUVECs) by statins were assessed. Results(i) Patients receiving high dose rosuvastatin had a marked decline in DKK-1 at day 2 which was maintained throughout the study period. However, a more prevalent use of β-blockers in the simvastatin group, that could have contributed to higher DKK-1 levels in these patients. (ii) There was a strong correlation between baseline DKK-1 levels and change in DKK-1 from baseline to day 2 in patients receiving high dose rosuvastatin treatment. (iii) DKK-3 increased at day 2 but returned to baseline levels at 2 months in both treatment groups. (iv) Statin treatment dose-dependently decreased DKK-1 mRNA and protein levels in HUVEC. ConclusionsOur findings suggest that high dose statin treatment with 40 mg rosuvastatin could persistently down-regulate DKK-1 levels, even at 2 months after the initial event in STEMI patients.

Albumin-to-alkaline phosphatase ratio may be a better predictor of survival than sclerostin, dickkopf-1, osteopontin, osteoprotegerin and osteocalcin

ObjectivesThe value of biochemical markers of bone turnover (BTMs) in predicting survival and disease remains unclear. In a prospective study we evaluated the novel biomarkers for bone turnover sclerostin, dickkopf-1 (DKK-1), osteopontin (OPN), osteoprotegerin (OPG) and osteocalcin (OC), as well as a traditional biomarker, alkaline phosphatase (ALP) in relation to risk of mortality, cardiovascular events and fractures. Participantsand Methods:Routine blood tests and serum BTMs, including ALP, were analyzed in patients with hip fracture n = 97, stroke n = 71 and healthy volunteers n = 83 (mean age 86, 83 and 77, respectively), followed for 7 years. Hazard Ratios (HR) were calculated for mortality, cardiovascular events and fractures in relation to these biomarkers. After adding the albumin-to-ALP ratio (AAPR) a post hoc analysis was performed. Results120 participants died during the study. In the entire group of patients and volunteers (n = 251) higher AAPR (HR 0.28, 95 % CI 0.14–0.59, p < 0.001) was associated with decreased mortality. OPN and OPG were associated with mortality risk only in the univariate statistical analysis. HR for high AAPR in relation to new cardiovascular events was borderline significant (HR 0.29, 95 % CI 0.08–1.06, p = 0.061). None of the examined biomarkers were associated with new fractures, nor with an increased risk of a new cardiovascular event. ConclusionsAAPR may be a better predictor of mortality than the more novel BTMs, and higher AAPR could be associated with longer life expectancy. Further studies should determine the clinical usefulness of AAPR as a biomarker of mortality and cardiovascular disease.

Bone tissue engineering based on sustained release of MiR29c-modified framework nucleic acids from an injectable hydrogel

Bone defects affect the daily activities of patients and are prevalent complications of various skeletal disorders. The miR29 family regulates bone physiology and pathological processes. MiR29c can inhibit Dickkopf-1 (DKK1) expression, up-regulate the Wnt-signaling pathway, and modify the intracellular microenvironment. However, its application is hindered by poor stability and low bioavailability. This study sought to optimize the nano miR29c delivery system, enable enhanced drug effects, stable drug in situ retention, and sustained drug release. Tetrahedral framework nucleic acids (tFNAs), which have excellent drug-loading ability, endocytic capacity, and stability, were used with sticky ends to deliver miR29c (i.e., stFNAs-miR29c). Porous gelatin methacryloyl (GelMA) was selected as a scaffold for the in situ sustained release of stFNAs-miR29c and to provide a growth environment for bone marrow mesenchymal stem cells (BMSCs). This research developed a miR29c sustained-release system in situ: GelMA-stFNAs-miR29c and demonstrated its osteogenesis in vitro and in vivo. GelMA, stFNAs, and miR29c can function synergistically at nano-, micro-, and macro- scales that achieves high stability and efficiency on microRNA nano-delivery, regulates the local microenvironment, maintains the macro-osteogenic space, accelerates the osteogenic process, and ensures excellent osteogenesis effects, contributing to the broader application of miRNAs in biomedicine and improved bone regeneration in situ.

Abstract 3925: Cancer-associated fibroblast-derived Dickkopf-1 impairs anti-tumor immunity in breast cancer by suppressing NK cell-mediated cytotoxicity

Abstract Despite early diagnosis, 10-20% of breast cancer patients experience metastatic disease within 5-10 years. While it is established that breast cancer cells have the capacity to evade immune responses, the mechanisms driving this evasion remain elusive. Therefore, finding ways to enhance anti-tumor immunity is crucial to improve patient outcomes. Dickkopf-1 (DKK1) is a Wnt inhibitor whose levels correlate with poor prognosis and decreased immune infiltration in various cancers. In this study, we used mice orthotopically injected with the PyMT, EO771, and 4T1 breast cancer lines. In all models, we found elevated DKK1 serum levels, and its neutralization with an αDKK1 Ab resulted in a significant reduction in primary tumor growth but also in metastatic dissemination. To identify the source of DKK1, we examined its expression in the tumor. DKK1 was detected in stromal cells with a fibroblast-like morphology but not in cancer cells or immune infiltrates. Co-staining confirmed colocalization between DKK1 and the CAF marker αSMA. To address the role of CAF-derived DKK1, we specifically deleted DKK1 in CAFs by generating FSP1CreDkk1fl/fl and αSMACreERT2Dkk1fl/fl mice. Both models showed a significant reduction in primary tumor growth while maintaining comparable serum DKK1 levels, indicating locally produced DKK1 supports tumor growth. To understand how DKK1 promotes tumor progression, we conducted bulk RNAseq of tumor cells isolated from IgG or αDKK1 treated mice. While no changes related to cell viability or cell cycle were observed, immune response-related genes were upregulated in αDKK1-treated cells. In support of this, αDKK1 did not reduce tumor growth in NSG immune-compromised mice. To pinpoint the immune cell targeted by DKK1, we depleted T, NK cells, or macrophages in WT tumor-bearing mice treated with αDKK1. Remarkably, only NK cell depletion negated αDKK1 anti-tumor effects. In vitro assays further demonstrated that rDKK1 or the presence of CAFs reduced NK cell cytotoxicity against tumor cells while αDKK1 restored it. To assess whether DKK1 levels correlated with tumor progression and immune suppression in breast cancer patients, we analyzed DKK1 serum levels and circulating NK cells at the diagnosis of metastatic bone disease and 15-18 months after standard care. DKK1 levels were significantly elevated in patients with progressive bone disease compared to those with stable disease. Importantly, NK cells from the progressive disease cohort had reduced perforin and granzyme B expression at the follow-up visit compared to baseline, indicating reduced cytotoxicity. Furthermore, rDKK1 reduced perforin in NK cells from healthy donors. In sum, our data show DKK1 is an important regulator of breast cancer progression, and we report for the first time DKK1 directly impairs NK cell cytotoxicity, creating an immune suppressive environment resistant to treatment. Citation Format: Seunghyun Lee, Biancamaria Ricci, Roberta Faccio. Cancer-associated fibroblast-derived Dickkopf-1 impairs anti-tumor immunity in breast cancer by suppressing NK cell-mediated cytotoxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3925.