Expression Patterns of the Wnt Pathway Inhibitors Dickkopf3 and Secreted Frizzled-Related Proteins 1 and 4 in Endometrial Endometrioid Adenocarcinoma: An NRG Oncology/Gynecologic Oncology Group Study

Secreted frizzled-related proteins: A promising therapeutic target for cancer therapy through Wnt signaling inhibition

The Wnt signaling system is a critical pathway that regulates embryonic development and adult homeostasis. Secreted frizzled-related proteins (SFRPs) are extracellular inhibitors of Wnt signaling that act by binding directly to Wnt ligands or Frizzled receptors. SFRPs can act as anti-Wnt agents and suppress cancer growth by blocking the action of Wnt ligands. However, SFRPs are often silenced by promoter methylation in cancer cells, resulting in hyperactivation of the Wnt pathway. Epigenetic modifiers can reverse this silencing and restore SFRPs expression. Despite the potential of SFRPs as a therapeutic target, the effects of SFRPs on tumor development remain unclear. Therefore, a review of the expression of various members of the SFRPs family in different cancers and their potential as therapeutic targets is warranted. This review aims to summarize the current knowledge of SFRPs in cancer, focusing on their expression patterns and their potential as novel therapeutic targets.

PBX1-promoted SFRP4 transcription inhibits cell proliferation and epithelial-mesenchymal transition in endometrial carcinoma

OBJECTIVE

To explore the effects and mechanisms of action of the PBX1/secreted frizzled-related protein 4 (SFRP4) axis in endometrial carcinoma (EC).

METHODS

The expression of PBX1 and SFRP4 was analyzed using bioinformatics prediction, followed by validation in EC cells using quantitative reverse transcription-polymerase chain reaction and western blotting. After transduction with overexpression vectors for PBX1 and SFRP4, migration, proliferation, and invasion of EC cells were measured, accompanied by the detection of E-cadherin, Snail, N-cadherin, Vimentin, β-catenin, GSK-3β, and C-myc expression. The association between PBX1 and SFRP4 was validated using dual luciferase reporter gene and chromatin immunoprecipitation assays.

RESULTS

PBX1 and SFRP4 were downregulated in EC cells. Overexpression of PBX1 or SFRP4 resulted in weakened cell proliferation, migration, and invasion, as well as decreased expression of Snail, N-cadherin, Vimentin, β-catenin, GSK-3β, and C-myc and increased expression of E-cadherin. PBX1 bound to the SFRP4 promoter and promoted its transcription. Knockdown of SFRP4 reversed the repression of overexpressed PBX1 in the malignant phenotypes and EMT of EC cells, and PBX1 repressed Wnt/β-catenin pathway activation by upregulating SFRP4 transcription.

CONCLUSION

PBX1 inhibited activation of the Wnt/β-catenin pathway by promoting SFRP4 transcription, thereby suppressing malignant phenotypes in EC cells and the EMT process.

Prediction of early recurrencies of uterine body cancer based on monitoring of serum biological markers

The aim of this work was to optimize the prognosis of early recurrences of uterine cancer by searching for informative laboratory biomarkers. The study included 343 patients with I-IV stages FIGO endometrial adenocarcinoma the ages of 53 and 76 years. In patients before surgery, as well as 3 and 6 months after the end of primary treatment, the concentration of oncological markers CA-125, HE4, DJ-1, DKK-1 was determined in blood serum by ELISA and electrochemiluminescence immunoassay. We analyzed the predictive informativeness of monitoring markers to assess the risk of early recurrences of cancer within two years after surgery. In patients with uterine cancer with the stage of the disease and the degree of tumor differentiation in the blood serum, the concentration of DJ-1 is changed. With myometrial invasion of more than 50%, increased serum levels of three markers - CA-125, HE4, and DJ-1. Depending on the risk of disease recurrence, the assessment of which was determined by intraoperative and histological characteristics, a difference was revealed in the content of HE4 and DJ-1 markers in the blood. It was found that the risk of early recurrence of uterine cancer increased (p<0,05) when the concentration of CA-125 exceeded the level of 29,3 U/ml, HE4 was above 79,3 pmol/l, DJ-1 was above 90,0 ng/ml and DKK-1 above 47,3 pg/ml 6 months after the end of primary treatment. The highest predictive information value was found for monitoring DJ-1 and HE4 in blood serum, which indicates that they are promising for use in continuous monitoring of the course of cancer.

The role of Wnt pathway antagonists in early-stage lung adenocarcinoma

PURPOSE

We aimed to examine the expression levels of the genes encoding adenomatous polyposis coli (APC) 1, APC-2, Dickkopf related protein (DKK)-1, DKK-3, secreted frizzled-related protein (SFRP)-2, SFRP-4, and SFRP-5, which play roles in the Wnt signaling pathway, in lung adenocarcinoma and adjacent normal lung tissues and to evaluate their relationships with clinicopathologic factors.

MATERIALS AND METHODS

The expression levels of genes in formalin-fixed paraffin-embedded samples of tumor tissue and adjacent intact lung tissue from 57 patients who underwent surgery for lung adenocarcinoma between 2011 and 2018 were determined by real-time PCR analysis.

RESULTS

The expression levels of the DKK-1 in tumor tissue, especially in stage I-II tumor tissue, were significantly suppressed compared to those in normal tissue (p < 0.025). Whereas DKK-1 expression was suppressed in the tumor tissue of patients with early-stage lung adenocarcinoma, expression of the SFRP-5 in these patients was significantly higher in tumor tissue than in normal tissue (p < 0.039).

CONCLUSION

In our study, opposing regulation was found between the SFRP-5 and DKK-1, which are known to be extracellular antagonists of the Wnt signaling pathway. The SFRP-5 was found to have an oncogenic role in adenocarcinoma development. Studies of the opposing regulation between these genes in early-stage lung adenocarcinoma may shed light on the mechanisms associated with the development of carcinogenesis. The relationships or interactions of these genes may serve as potential therapeutic targets.

Addressing activation of WNT beta-catenin pathway in diverse landscape of endometrial carcinogenesis

The WNT-beta-catenin pathway (WP) is one of the major oncogenic pathways in solid tumors. Wnt beta-catenin pathway plays a unique role in a wide range of endometrial dysfunctions, from embryo implantation failure to severe pathogenic changes like endometriosis and endometrial cancer. Although abnormal activation of the pathway has long been known to be associated with endometrial tumorigenesis, the pathway's exact mode of involvement remains to be understood. As more evidence has been presented in favor of a crucial role of the WP in solid tumors, including endometrial cancer, anti-WP drugs are currently being tested to manage the disease. Aggressive tumor cells are nurtured by the tumor microenvironment (TME). The genetic alterations within tumor cells are the primary driving force to activate the extra-tumoral micro-environment. TME (a) provides metabolic support for the proliferation of tumor cells, (b) orchestrates immune-evasion, (c) initiates mechanistic signaling for several metastasis-associated phenotypes, and (d) supports cellular events for the development of drug resistance. To get metabolic as well as immune support from the tumor microenvironment, tumor cells cross-talk with components of the TME, most critically to the cancer-associated fibroblasts. Thus it is expected that the tumor-TME cross-talk throughout the process of tumorigenesis and metastasis is one of the characteristic features of an aggressive tumor. Here we review the WP's mechanistic involvement as a common culprit (Un Colpevole Comune) in endometrial tumor cells and endometrial cancer-associated fibroblast (CAF). In this review, we have attempted to discuss the activation of the WP in the genesis and progression of endometrial cancers, including endometrial tumor biology, tumor microenvironment, cancer-associated fibroblasts, and wnt-beta catenin genetic alteration. We interrogated the available literature on the various aspects of endometrial carcinogenesis leading to the pathway's activation. We examined how genetic alterations in WP directly influence tumor cell signaling to bring out different tumor cell phenotypes, and present palpable evidence to envision a role of WP inhibitors in the future management of the disease.

Dickkopf Proteins and Their Role in Cancer: A Family of Wnt Antagonists with a Dual Role

The Wnt signaling pathway regulates crucial aspects such as cell fate determination, cell polarity and organogenesis during embryonic development. Wnt pathway deregulation is a hallmark of several cancers such as lung, gastric and liver cancer, and has been reported to be altered in others. Despite the general agreement reached by the scientific community on the oncogenic potential of the central components of the pathway, the role of the antagonist proteins remains less clear. Deregulation of the pathway may be caused by overexpression or downregulation of a wide range of antagonist proteins. Although there is growing information related to function and regulation of Dickkopf (DKK) proteins, their pharmacological potential as cancer therapeutics still has not been fully developed. This review provides an update on the role of DKK proteins in cancer and possible potential as therapeutic targets for the treatment of cancer; available compounds in pre-clinical or clinical trials are also reviewed.

Emerging role of phytochemicals in targeting predictive, prognostic, and diagnostic biomarkers of lung cancer

Lung-cancer is the foremost cause of cancer in humans worldwide, of which 80-85% cases are composed of non-small cell lung carcinoma. All treatment decisions depend on the pattern of biomarkers selection to enhance the response to the targeted therapies. Although advanced treatments are available for lung-cancer, the disease treatment remains not adequate. There are several synthetic chemotherapeutic agents available for the treatment of lung cancer. However, due to their toxic effect, survival rate is still 15-18%. Besides, medicinal plants are a huge reservoir of natural products that provide protective effects against lung cancer. Likewise, successful studies of potential phytochemicals in targeting lung-cancer biomarkers have created a novel paradigm for the discovery of potent drugs against lung-cancer. Hence, to defeat severe toxicity and resistance towards the synthetic drugs, detailed studies are required regarding the available phytochemicals and targets responsible for the treatment of lung-cancer. The present review provides a comprehensive information about the lung-cancer biomarkers under the classification of predictive, prognostic, and diagnostic type. Moreover, it discusses and enlists the phytochemicals with mode of action against different biomarkers, effective doses in in vitro, in vivo, and clinical studies, the limitations associated with usage of phytochemicals as a drug to prevent/cure lung-cancer and the latest techniques employed to overcome such issues.

Cyclooxygenase-2 and β-Catenin as Potential Diagnostic and Prognostic Markers in Endometrial Cancer

Objectives: Explore the diagnostic and prognostic value of cyclooxygenase-2 and wnt3a/β-catenin pathway in endometrial cancer.

Methods: A prospective cohort study of 93 women underwent hysterectomy at the China-Japan Friendship Hospital (61 patients with primary endometrial carcinoma, and 32 control patients with uterine prolapse or leiomyoma of uterus). Cox2 and β-catenin expression were determined by immunohistochemistry. The serum levels of cox2 and wnt3a were detected via ELISA assays.

Results: Patients with endometrial cancer showed overexpression of cox2 and β-catenin, as well as significantly higher serum levels of cox2 and wnt3a. The serum cox2 level, which is highly significant in predicting the risk of disease progression (RR, 9.617, 95% confidence interval, 1.162–79.622, P = 0.036), showed good diagnostic and prognostic potential, with cut-off of 55 U/L, but alongside β-catenin expression in tissues, were related to poor prognosis (RR, 12.426; 95% confidence interval, 1.618–95.450; P = 0.015).

Conclusion: Serum levels of cox2 and wnt3a exhibited diagnostic value for endometrial cancer. Cox2 serum levels and β-catenin expression also showed potential value of prognostic prediction. Cox2 serum levels might be a potential marker for early diagnosis and prognosis prediction in endometrial cancer.

Overexpression of enhance of Zeste homolog 2 (EZH2) in endometrial carcinoma: An NRG Oncology/Gynecologic Oncology Group Study

OBJECTIVES

Enhancer of zeste homolog 2 (EZH2) is a histone methyl transferase that mediates epigenetic silencing of tumor suppressor genes. It is commonly over-expressed in several solid tumors and has been shown to be a prognostic biomarker. We investigated patterns of EZH2 expression in endometrial cancer.

METHODS

Evaluation of EZH2 expression was completed on both early and advanced stage endometrioid adenocarcinoma tissues and a subset of matched normal mullerian tissue samples, from participants enrolled in Gynecologic Oncology Group (GOG) protocol 210, using real time reverse transcription polymerase chain reaction (RT-PCR) and western blot (WB) analysis. Non-parametric methods were used to assess differences in mRNA and protein expression respectively with known clinical/pathologic prognostic factors. Survival analysis was performed using techniques including Cox proportional hazards (PH) model to evaluate differences in progression free survival (PFS) and overall survival (OS) based on EZH2 expression.

RESULTS

Eighty-seven patient samples were analyzed that included 60 tumors and 27 matched-normal tissue specimens. EZH2 mRNA (p < .0001) and protein expression (p < .0001) in tumor specimens were significantly higher than in matched-normal tissue. In primary tumors, EZH2 protein expression was associated with lympho-vascular space invasion (LVSI, p = .044), and EZH2 mRNA expression was associated with age (p = .037). Differences in EZH2 expression between primary tumors and matched normal tissue were not associated with other known clinical and pathologic factors. However, there did appear to be a trend toward decreased progression-free survival among patients with high EZH2 expression levels.

CONCLUSIONS

Our results confirm the differential expression of EZH2 in uterine cancers compared to normal tissues. However, there were no statistically significant differences in survival associated with EZH2 expression in patients with endometrial cancer. NCT #: NCT00340808.

A potpourri of pathogenetic pathways in endometrial carcinoma with a focus on Lynch Syndrome

Endometrial carcinoma is the most frequently occurring female genital tract malignancy in developed nations, with a rising annual incidence. Endometrioid endometrial carcinoma (EEC), the most common histological variant, differs in morphologic and molecular characteristics from serous carcinomas but morphological distinction of high-grade EECs from serous carcinomas may prove difficult. Thus, molecular categorization of tumors may allow for better tumor classification with greater insight into the underlying biology of endometrial carcinomas with new therapeutic options. Microsatellite instability (MSI) is a commonly occurring molecular aberration in EECs and has been identified in most Lynch Syndrome (LS) associated tumors. This tumor syndrome predisposes afflicted individuals to a myriad of tumors including endometrial carcinoma. Herein, the molecular signature of endometrial tumors as well as LS, and its clinical manifestations are reviewed. Understanding of the pathogenetic pathways allows for greater comprehension of occurrences at a molecular level which are then appreciated at a cellular and tissue level, by the histopathologist. The molecular classification of endometrial tumors allows for further targeted therapeutic options for affected patients. Screening tests for patients with suspected LS enables surveillance of other tumors in the affected patient and her family with the potential to decrease morbidity and mortality. It is envisioned that this overview will allow for enhanced comprehension of genetic pathways by practicing pathologists, oncologists, gynecologists and other members of the multidisciplinary team, all of whom are involved in the management of the patient with an endometrial malignancy.

Dickkopf-3 Causes Neuroprotection by Inducing Vascular Endothelial Growth Factor

Dickkopf-3 (Dkk3) is an atypical member of the Dkk family of Wnt inhibitors, which has been implicated in the pathophysiology of neurodegenerative disorders. However, the role of Dkk3 in mechanisms of cell degeneration and protection is unknown. We used Dkk3 knockout mice to examine how endogenous Dkk3 influences ischemic brain damage. In addition, we used primary cultures of astrocytes or mixed cultures of astrocytes and neurons to investigate the action of Dkk3 on cell damage and dissect the underlying molecular mechanisms. In a model of focal brain ischemia induced by permanent middle cerebral artery (MCA) occlusion (MCAO) Dkk3^−/− mice showed a significantly greater infarct size with respect to their wild-type counterparts at all time points investigated (1, 3 and 7 days after MCAO). Immunohistochemical analysis showed that Dkk3 expression was enhanced at the borders of the ischemic focus, and was predominantly detected in astrocytes. This raised the possibility that Dkk3 produced by astrocytes acted as a protective molecule. We tested this hypothesis using either primary cultures of cortical astrocytes or mixed cortical cultures containing both neurons and astrocytes. Genetic deletion of Dkk3 was permissive to astrocyte damage induced by either oxidative stress or glucose deprivation. In addition, application of human recombinant Dkk3 (hrDkk3) was highly protective against oxidative stress in cultured astrocytes. We tested the hypothesis that the protective activity of Dkk3 was mediated byvascular endothelial growth factor (VEGF). Interestingly, glucose deprivation up-regulated both Dkk3 and VEGF in cultured astrocytes prepared from wild-type mice. VEGF induction was not observed in astrocytes lacking Dkk3 (i.e., in cultures prepared from Dkk3^−/− mice). In mixed cultures of cortical cells, excitotoxic neuronal death induced by a brief pulse with N-methyl-D-aspartate (NMDA) was significantly enhanced when Dkk3 was lacking in astrocytes, whereas post-NMDA addition of hrDkk3 was neuroprotective. Neuroprotection by hrDkk3 was significantly reduced by pharmacological blockade of type-2 VEGF receptors and was mimicked by hrVEGF. These data offer the first evidence that Dkk3 protects both neurons and astrocytes against a variety of toxic insults, and at least in culture, protection involves VEGF induction.

An update of Wnt signalling in endometrial cancer and its potential as a therapeutic target

Endometrial cancer is the most common gynaecological malignancy in developed nations, and its prevalence is rising as women defer or decide not to have children and as obesity rises, both key risk factors. Despite this, treatment options remain limited, particularly for advanced or refractory disease. New genomic analyses have revealed distinct mutational profiles with therapeutic and prognostic potential. Wnt signalling, which is pivotal in embryogenesis, healing and homeostasis, is of importance in the endometrium and has been linked to carcinogenesis. This review aims to update and discuss the current evidence for the role of β-catenin dependent and independent Wnt signalling, including the ROR receptors in the endometrium and its potential as a therapeutic target, in light of recent trials of Wnt-targeted therapy in multiple tumour types.

Secreted frizzled related protein 4 (sFRP4) update: A brief review

Secreted frizzled-related proteins control a multitude of biological phenomena throughout development and adult life in humans. In parallel, aberrant gene expression and abnormal secreted protein levels accompany a wide range of pathologies in humans. In this review, we provide a brief introduction to sFRP4, an update of the pathways it's involved, its various physiological actions that are reported to contribute to diseases, outlining the importance of its wider research and specific modulation by pharmacologic interventions. First recognized as a novel molecule that co-purified with a disparate protein, its identity was based on its sequence homology to the frizzled receptors. Once multiple members of the family were cloned, their genetic loci, tissue and subcellular distributions were located. Nucleotide and amino acid sequences were characterized and homology to different organisms was found to be present that helped elucidate their actions. Following subsequent experimental studies, they were found to be secreted proteins with an affinity to bind to the Wnt ligands, participating in different developmental and adult homeostatic pathways by the virtue of their regulatory function to the Wnt signal transduction system. Secreted frizzled related protein 4 has garnered considerable attention in the recent years following breakthrough discoveries implicating them in the pathogenesis of various diseases. Studies investigating them can provide information not only regarding their association with a disease but can also help use them as potential biomarkers and therapeutic targets.

MiRNA-27a promotes the proliferation and invasion of human gastric cancer MGC803 cells by targeting SFRP1 via Wnt/β-catenin signaling pathway

This study aims to elucidate the effects of microRNA-27a (miR-27a) on the proliferation and invasion of gastric cancer (GC) cells by targeting SFRP1 via Wnt/β-catenin signaling pathway. GC and normal adjacent tissues were collected from 273 GC patients. Human gastric cancer cell line (MGC803) and normal human gastric mucosal cell line (GES-1) were cultured. The miR-27a mRNA expression was analyzed using Quantitative real-time polymerase chain reaction (qRT-PCR). Immunohistochemistry (IHC) test was used to detect miR-27a and SFRP1 protein expressions. After transfection, cells were divided into five groups: the negative control (NC) group, the miR-27a inhibitor group, the miR-27a mimics group, the miR-27a inhibitor + SFRP1 siRNA group and the miR-27a mimics + SFRP1 overexpression group. Western blotting was conducted to test SFRP1 and Wnt/β-catenin protein expression. Analysis for the target gene of miR-27a was performed using Luciferase assay. Cell proliferation, migration and invasion were determined by CCK8 and Transwell assay. The dual-luciferase reporter assay system was applied to analyze the effects of miR-27a on Wnt/β-catenin signaling pathway. In GC tissue and cell line, miR-27a protein and mRNA expressions were up-regulated, and SFRP1 protein and mRNA expressions were down-regulated. Luciferase assay indicated that miR-27a might target SFRP1 and regulate its expressions. When miR-27a was down-regulated, SFRP1 was up-regulated, and β-catenin, Wnt, p-β-catenin, and p-Wnt were significantly down-regulated. Compared with the NC group, the proliferation, migration and invasion of GC cells were remarkably increased in the miR-27a group, but these were declined in the miR-27a mimics + SFRP1 overexpression group. The proliferation, migration and invasion of GC cells were elevated in the miR-27a inhibitor + SFRP1 siRNA group compared with the miR-27a inhibitor group. These results showed that miR-27a was highly expressed in GC tissues and cells, and it might promote cell proliferation, migration and invasion by targeting SFRP1 via the activation of Wnt/β-catenin signaling pathway.

Prostaglandin E2 (PGE2) promotes proliferation and invasion by enhancing SUMO-1 activity via EP4 receptor in endometrial cancer

Prostaglandin E2 (PGE2), a derivative of arachidonic acid, has been identified as a tumorigenic factor in many cancers in recent studies. Prostaglandin E synthase 2 (PTGES2) is an enzyme that in humans is encoded by the PTGES2 gene located on chromosome 9, and it synthesizes PGE2 in human cells. In our study, we selected 119 samples from endometrial cancer patients, with 50 normal endometrium tissue samples as controls, in which we examined the expression of PTGES2. Both immunohistochemistry (IHC) and Western blot analyses demonstrated that synthase PTGES2, which is required for PGE2 synthesis, was highly expressed in endometrium cancer tissues compared with normal endometrium. Stable PTGES2-shRNA transfectants were generated in Ishikawa and Hec-1B endometrial cancer cell lines, and transfection efficiencies were confirmed by RT-PCR and Western blot analyses. We found that PGE2 promoted proliferation and invasion of cells in Ishikawa and Hec-1B cells by cell counting kit-8 tests (CCK8) and transwell assays, respectively. PGE2 stimulation enhanced the expression of SUMO-1, via PGE2 receptor subtype 4 (EP4). Further analysis implicated the Wnt/β-catenin signaling pathway function as the major mediator of EP4 and SUMO-1. The increase in SUMO-1 activity prompted the SUMOlyation of target proteins which may be involved in proliferation and invasion. These findings suggest SUMO-1 and EP4 as two potential targets for new therapeutic or prevention strategies for endometrial cancers.