International Union of Basic and Clinical Pharmacology. CXV: The Class F of G Protein-Coupled Receptors.

The class F of G protein-coupled receptors (GPCRs) consists of ten Frizzleds (FZD1-10) and Smoothened (SMO). FZDs bind and are activated by secreted lipoglycoproteins of the Wingless/Int-1 (WNT) family and SMO is indirectly activated by the Hedgehog (Hh) family of morphogens acting on the transmembrane protein Patched (PTCH). The advance of our understanding of FZDs and SMO as dynamic transmembrane receptors and molecular machines, which emerged during the past 14 years since the first class F GPCR IUPHAR nomenclature report, justifies an update. This article focuses on the advances in molecular pharmacology and structural biology providing new mechanistic insight into ligand recognition, receptor activation mechanisms, signal initiation and signal specification. Furthermore, class F GPCRs continue to develop as drug targets, and novel technologies and tools such as genetically encoded biosensors and CRISP/Cas9 edited cell systems have contributed to refined functional analysis of these receptors. Also, advances in crystal structure analysis and cryogenic electron microscopy contribute to a rapid development of our knowledge about structure-function relationships providing a great starting point for drug development. Despite the progress questions and challenges remain to fully understand the complexity of the WNT/FZD and Hh/SMO signaling systems. Significance Statement The recent years of research have brought about substantial functional and structural insight into mechanisms of activation of Frizzleds and Smoothened. While the advance furthers our mechanistic understanding of ligand recognition, receptor activation, signal specification and initiation, broader opportunities emerge that allow targeting class F GPCRs for therapy and regenerative medicine employing both biologics and small molecule compounds.

Molecular landscape of borderline ovarian tumours: A systematic review.

Borderline ovarian tumours (BOTs) show intriguing characteristics distinguishing them from other ovarian tumours. The aim of the systematic review was to analyse the spectrum of molecular changes found in BOTs and discuss their significance in the context of the overall therapeutic approach. The systematic review included articles published between 2000 and 2023 in the databases: PubMed, EMBASE, and Cochrane. After a detailed analysis of the available publications, we qualified for the systematic review: 28 publications on proto-oncogenes: BRAF, KRAS, NRAS, ERBB2, and PIK3CA, 20 publications on tumour suppressor genes: BRCA1/2, ARID1A, CHEK2, PTEN, 4 on adhesion molecules: CADM1, 8 on proteins: B-catenin, claudin-1, and 5 on glycoproteins: E-Cadherin. In addition, in the further part of the systematic review, we included eight publications on microsatellite instability and three describing loss of heterozygosity in BOT. Molecular changes found in BOTs can vary on a case-by-case basis, identifying carcinogenic mutations through molecular analysis and developing targeted therapies represent significant advancements in the diagnosis and treatment of ovarian malignancies. Molecular studies have contributed significantly to our understanding of BOT pathogenesis, but substantial research is still required to elucidate the relationship between ovarian neoplasms and extraneous disease, identify accurate prognostic indicators, and develop targeted therapeutic approaches.

Therapeutic avenues in bone repair: Harnessing an anabolic osteopeptide, PEPITEM, to boost bone growth and prevent bone loss.

The existing suite of therapies for bone diseases largely act to prevent further bone loss but fail to stimulate healthy bone formation and repair. We describe an endogenous osteopeptide (PEPITEM) with anabolic osteogenic activity, regulating bone remodeling in health and disease. PEPITEM acts directly on osteoblasts through NCAM-1 signaling to promote their maturation and formation of new bone, leading to enhanced trabecular bone growth and strength. Simultaneously, PEPITEM stimulates an inhibitory paracrine loop: promoting osteoblast release of the decoy receptor osteoprotegerin, which sequesters RANKL, thereby limiting osteoclast activity and bone resorption. In disease models, PEPITEM therapy halts osteoporosis-induced bone loss and arthritis-induced bone damage in mice and stimulates new bone formation in osteoblasts derived from patient samples. Thus, PEPITEM offers an alternative therapeutic option in the management of diseases with excessive bone loss, promoting an endogenous anabolic pathway to induce bone remodeling and redress the imbalance in bone turnover.

Prognostic significance of E-Cadherin and B-Catenin in non-muscle invasive bladder cancer.

Non muscle invasive bladder cancer (NMIBC) has unpredictable outcomes with a variable risk of recurrence and progression. Many clinic-pathological prognostic factors have been identified but remain insufficient, raising the need to investigate new biomarkers. The aim of our study was to assess the prognostic value of the immunohistochemical (IHC) markers E-Cadherin and B-Catenin in NMIBC. All cases of NMIBC were collected between 2008 and 2013. IHC analysis was performed using E-Cadherin and B-Catenin. Reduced or loss of E-Cadherin expression was assessed as abnormal. Only cases with B-Catenin intense membranous staining were considered normal. A correlation was found between abnormal E-Cadherin expression and stage (p = 0.001), grade (p = 0.0000000), recurrence (p = 0.0000000), progression (p = 0.01), recurrence-free survival (p = 0.00000001), and progression-free survival (p = 0.01). A statistically significant association was found between B-Catenin and stage (p = 0. 05), grade (p = 0.02), and recurrence (p = 0.02). The abnormal expression of these markers could help to identify a high-risk subgroup of NMIBC that might benefit from either more accurate follow-up or more aggressive treatment.

Wnt/ß-catenin signaling activation promotes lipogenesis in the steatotic liver via physical mTOR interaction.

Background and aims: Wnt/ß-catenin signaling plays an important role in regulating hepatic metabolism. This study is to explore the molecular mechanisms underlying the potential crosstalk between Wnt/ß-catenin and mTOR signaling in hepatic steatosis. Methods: Transgenic mice (overexpress Wnt1 in hepatocytes, Wnt+) mice and wild-type littermates were given high fat diet (HFD) for 12 weeks to induce hepatic steatosis. Mouse hepatocytes cells (AML12) and those transfected to cause constitutive ß-catenin stabilization (S33Y) were treated with oleic acid for lipid accumulation. Results: Wnt+ mice developed more hepatic steatosis in response to HFD. Immunoblot shows a significant increase in the expression of fatty acid synthesis-related genes (SREBP-1 and its downstream targets ACC, AceCS1, and FASN) and a decrease in fatty acid oxidation gene (MCAD) in Wnt+ mice livers under HFD. Wnt+ mice also revealed increased Akt signaling and its downstream target gene mTOR in response to HFD. In vitro, increased lipid accumulation was detected in S33Y cells in response to oleic acid compared to AML12 cells reinforcing the in vivo findings. mTOR inhibition by rapamycin led to a down-regulation of fatty acid synthesis in S33Y cells. In addition, ß-catenin has a physical interaction with mTOR as verified by co-immunoprecipitation in hepatocytes. Conclusions: Taken together, our results demonstrate that ß-catenin stabilization through Wnt signaling serves a central role in lipid metabolism in the steatotic liver through up-regulation of fatty acid synthesis via Akt/mTOR signaling. These findings suggest hepatic Wnt signaling may represent a therapeutic strategy in hepatic steatosis.

Induced pluripotent stem cells modulate the Wnt pathway in the bleomycin-induced model of idiopathic pulmonary fibrosis.

BACKGROUND: The Wnt signaling pathway has been implicated in the pathogenesis of fibrotic disorders and malignancies. Hence, we aimed to assess the potential of the induced pluripotent stem cells (IPS) in modulating the expression of the cardinal genes of the Wnt pathway in a mouse model of idiopathic pulmonary fibrosis (IPF). METHODS: C57Bl/6 mice were randomly divided into three groups of Control, Bleomycin (BLM), and BLM + IPS; the BLM mice received intratracheal instillation of bleomycin, BLM + IPS mice received tail vein injection of IPS cells 48 h post instillation of the BLM; The Control group received Phosphate-buffered saline instead. After 3 weeks, the mice were sacrificed and Histologic assessments including hydroxy proline assay, Hematoxylin and Eosin, and Masson-trichrome staining were performed. The expression of the genes for Wnt, ß-Catenin, Lef, Dkk1, and Bmp4 was assessed utilizing specific primers and SYBR green master mix. RESULTS: Histologic assessments revealed that the fibrotic lesions and inflammation were significantly alleviated in the BLM + IPS group. Besides, the gene expression analyses demonstrated the upregulation of Wnt, ß-Catenin, and LEF along with the significant downregulation of the Bmp4 and DKK1 in response to bleomycin treatment; subsequently, it was found that the treatment of the IPF mice with IPS cells results in the downregulation of the Wnt, ß-Catenin, and Lef, as well as upregulation of the Dkk1, but not the Bmp4 gene (P values < 0.05). CONCLUSION: The current study highlights the therapeutic potential of the IPS cells on the IPF mouse model in terms of regulating the aberrant expression of the factors contributing to the Wnt signaling pathway.

NEAT1-mediated miR-150-5p downregulation regulates b-catenin expression in OA chondrocytes.

We investigated the role of miR-150-5p in osteoarthritic (OA) chondrocytes, as well as the possible regulatory role of long non-coding RNAs (lncRNAs) in miR-150-5p expression. TargetScan, StarBase, DIANA-LncBase, and Open Targets databases were used to predict miR-150-5p target genes, lncRNAs/miR-150-5p interactions, and OA-related genes. Protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING). Gene ontology (GO) and pathway analysis were performed using Enrichr database. A publicly available RNA-seq dataset was retrieved to identify differentially expressed lncRNAs in damaged vs intact cartilage. We re-analyzed the retrieved RNA-seq data and revealed 177 differentially expressed lncRNAs in damage vs intact cartilage, including Nuclear Paraspeckle Assembly Transcript 1(NEAT1). MiR-150-5p, NEAT1, b-catenin, matrix metallopeptidase 13 (MMP-13), and ADAM metallopeptidase with thrombospondin type 1 motif 5 (ADAMTS-5) expressions were assessed by reverse transcription-quantitative PCR (RT-qPCR) and western blot assay. Knockout and transfection experiments were conducted to investigate the role of NEAT1/miR-150-5p/b-catenin in cartilage degradation. Bioinformatics analysis revealed that b-catenin was an OA-related miR-150-5p target. MiR-150-5p overexpression in OA chondrocytes resulted in decreased expression of b-catenin, as well as MMP-13 and ADAMTS-5, both being Wnt/b-catenin downstream target genes. NEAT1/miR-150-5p interaction was predicted by bioinformatics analysis, while NEAT1 knockout led to increased expression of miR-150-5p in OA chondrocytes. Moreover, inhibition of miR-150-5p reversed the repressive effects of NEAT1 silencing in b-catenin expression in OA chondrocytes. Our results support a possible catabolic role of NEAT1/miR-150-5p interaction in OA progression by regulating b-catenin expression.

The association of Wnt-signalling and EMT markers with clinical characteristics in women with endometrial cancer.

Endometrial cancer is the most common gynecologic malignancy in the developed world. Risk stratification and treatment approaches are changing due to better understanding of tumor biology. Upregulated Wnt signaling plays an important role in cancer initiation and progression with promising potential for development of specific Wnt inhibitor therapy. One of the ways in which Wnt signaling contributes to progression of cancer, is by activating epithelial-to-mesenchymal transition (EMT) in tumor cells, causing the expression of mesenchymal markers, and enabling tumor cells to dissociate and migrate. This study analyzed the expression of Wnt signaling and EMT markers in endometrial cancer. Wnt signaling and EMT markers were significantly correlated with hormone receptors status in EC, but not with other clinico-pathological characteristics. Expression of Wnt antagonist, Dkk1 was significantly different between the ESGO-ESTRO-ESP patient risk assessment categories using integrated molecular risk assessment.

Interferon-dependent SLC14A1+ cancer-associated fibroblasts promote cancer stemness via WNT5A in bladder cancer.

Cancer-associated fibroblasts (CAFs) play a role in response to cancer treatment and patient prognosis. CAFs show phenotypic and functional heterogeneity and differ widely in tumors of different tissue origin. Here, we use single-cell RNA sequencing of bladder cancer (BC) patient samples and report a CAF subpopulation characterized by overexpression of the urea transporter SLC14A1. This population is induced by interferon signaling and confers stemness to BC cells via the WNT5A paracrine pathway. Activation of cGAS-STING signaling in tumor cells drives interferon production, thereby revealing a link between cGAS-STING signaling and SLC14A1+ CAF differentiation. Furthermore, the inhibition of SLC14A1+ CAF formation via targeting of STAT1 or STING sensitizes tumor cells to chemotherapy. More important, BC patients with high proportions of intratumoral SLC14A1+ CAFs show cancer stage-independent poor outcome and a worse response rate to neoadjuvant chemotherapy or immunotherapy.

¿Cuándo el patólogo debe solicitar inmunomarcación con B-Catenina?: una revisión de la literatura a propósito de dos casos / When should the pathologist request immunostaining with B-catenin?: a review of the literature on two cases

For more than 20 years, immunohistochemistry has represented an auxiliary test of great relevance to support pathological work, however, it should be noted that the pillar of diagnosis continues and will continue to be the classic morphological description based on hematoxylin eosin and the trained eye of the specialist. In neoplastic pathologies, whether benign or malignant, it is becoming increasingly necessary to incorporate new tissue biomarkers that help objectify or confirm the diagnosis of each patient, in order to provide better treatment or a more precise diagnosis about the biological nature of their illness. In this line, there has been intense research in relation to the participation of the Wnt/ß-catenin pathway in the development of various types of tumors, including colon adenocarcinoma, some pancreatic neoplasms and even some tumors of mesenchymal origin, as will be seen. in this work. In this context and based on two clinical cases of special interest, we have prepared a brief review of the literature considering the biological aspects of ß-catenin, tumors where there is currently a true relative consensus that its immunolabeling offers a real contribution to the confirmation of the entity and finally a limited exposition regarding the future of this biomarker in the pathology discipline.

Desde hace más de 20 años la inmunohistoquímica ha representado una prueba auxiliar de gran relevancia para apoyar el trabajo anatomopatológico, no obstante, cabe señalar que, aún el pilar del diagnóstico sigue y seguirá siendo la descripción morfológica clásica basada en hematoxilina eosina y el ojo entrenado del especialista. En las patologías neoplásicas, ya sea benignas, como malignas, se hace cada vez más necesario la incorporación de nuevos biomarcadores tisulares que ayuden a objetivar o confirmar el diagnóstico de cada paciente, con objeto de entregar un mejor tratamiento o un diagnóstico más preciso de la naturaleza biológica de su enfermedad. En esta línea, ha habido intensa investigación en relación con la participación de la vía Wnt/ß-catenina en el desarrollo de varios tipos de cáncer, entre ellos el adenocarcinoma de colon, algunas neoplasias pancreáticas e incluso algunos tumores de origen mesenquimal como se verá en este trabajo. En este contexto y partir de dos casos clínicos de especial interés, hemos preparado una breve revisión de la literatura considerando los aspectos biológicos de la ß-catenina, los tumores donde en la actualidad existe verdadero consenso de que su inmunomarcación ofrece un aporte real a la confirmación de la entidad y finalmente una exposición acotada respecto al futuro de este biomarcador en la disciplina de la anatomía patológica.

Application of Cell-Derived Extracellular Vesicles and Engineered Nanovesicles for Hair Growth: From Mechanisms to Therapeutics.

Hair loss is one of the most common disorders that affect both male and female patients. Cell-derived nanovesicles (CDVs) are natural extracellular vesicles and engineered nanovesicles that can carry various biologicals materials such as proteins, lipids, mRNA, miRNA, and DNA. These vesicles can communicate with local or distant cells and are capable of delivering endogenous materials and exogenous drugs for regenerative therapies. Recent studies revealed that CDVs can serve as new treatment strategies for hair growth. Herein, we review current knowledge on the role of CDVs in applications to hair growth. The in-depth understanding of the mechanisms by which CDVs enable therapeutic effects for hair growth may accelerate successful clinical translation of these vesicles for treating hair loss.

Effect of bone marrow mesenchymal stem cells-derived exosomes on diabetes-induced retinal injury: Implication of Wnt/ b-catenin signaling pathway.

BACKGROUND: Diabetic retinopathy (DR) is a serious microvascular complication of diabetes mellitus. Mesenchymal stem cells are currently studied as therapeutic strategy for management of DR. Exosomes, considered as a promising cell-free therapy option, display biological functions similar to those of their parent cells. In retinal development, Wnt/b-catenin signaling provides key cues for functional progression. The present study aimed to evaluate the potential efficacy of bone marrow-derived mesenchymal stem cell-derived exosomes (BM-MSCs-Ex) in diabetes-induced retinal injury via modulation of the Wnt/ b-catenin signaling pathway. METHODS: Eighty-one rats were allocated into 6 groups (control, DR, DR + DKK1, DR + exosomes, DR + Wnt3a and DR + exosomes+Wnt3a). Evaluation of each group was via histopathological examination, assessment of gene and/or protein expression concerned with oxidative stress (SOD1, SOD2, Nox2, Nox4, iNOS), inflammation (TNF-α, ICAM-1, NF-κB) and angiogenesis (VEGF, VE-cadherin). RESULTS: Results demonstrated that exosomes blocked the wnt/b-catenin pathway in diabetic retina concomitant with significant reduction of features of DR as shown by downregulation of retinal oxidants, upregulation of antioxidant enzymes, suppression of retinal inflammatory and angiogenic markers. These results were further confirmed by histopathological results, fundus examination and optical coherence tomography. Additionally, exosomes ameliorative effects abrogated wnt3a-triggered retinal injury in DR. CONCLUSION: Collectively, these data demonstrated that exosomes ameliorated diabetes-induced retinal injury via suppressing Wnt/ b-catenin signaling with subsequent reduction of oxidative stress, inflammation and angiogenesis.

Bone Marrow Adiposity, Bone Mineral Density and Wnt/ß-catenin Pathway Inhibitors Levels in Hemodialysis Patients.

BACKGROUND: Marrow adipose tissue (MAT) is known to accumulate in patients with chronic kidney disease. This pilot study aimed to evaluate bone mineral density (BMD), MAT, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) using computed tomography (CT) scans and to explore correlations between bone parameters, circulating Wnt/ß-catenin pathway inhibitor levels, and adipose tissue parameters. METHODS: Single-center cross-sectional pilot study conducted in hemodialysis patients at the Centre Universitaire de Québec, Hôtel-Dieu de Québec hospital, Canada. CT-scan slices were acquired at the levels of the hip, L3 vertebra, and tibia. Volumetric and areal BMD, tibia cortical thickness, VAT and SAT area, and fat marrow index (FMI) were analyzed using the Mindways QCT Pro software. Blood levels of sclerostin, dickkopf-related protein 1 (DKK1), fibroblast growth factor 23, and α-Klotho were assessed. Spearman's rho test was used to evaluate correlations. RESULTS: Fifteen hemodialysis patients (median age, 75 [66-82] years; 80% male; dialysis vintage, 39.3 [27.4-71.0] months) were included. While inverse correlations were obtained between L3 FMI and BMD, positive correlations were found between proximal tibial FMI and vertebral and tibial BMD, as well as with tibial (proximal and distal) cortical thickness. VAT had a positive correlation with α-Klotho levels, whereas L3 FMI had a negative correlation with DKK1 levels. CONCLUSIONS: CT-scan allows simultaneous evaluation of bone and marrow adiposity in dialysis patients. Correlations between MAT and BMD vary depending on the bone site evaluated. DKK1 and α-Klotho levels correlate with adipose tissue accumulation in dialysis patients.

Corrigendum: Upregulation of CCT-3 Induces Breast Cancer Cell Proliferation Through miR-223 Competition and Wnt/b-Catenin Signaling Pathway Activation.

[This corrects the article DOI: 10.3389/fonc.2020.533176.].

Identification of Synergistic Drug Combinations to Target KRAS-Driven Chemoradioresistant Cancers Utilizing Tumoroid Models of Colorectal Adenocarcinoma and Recurrent Glioblastoma.

Treatment resistance is observed in all advanced cancers. Colorectal cancer (CRC) presenting as colorectal adenocarcinoma (COAD) is the second leading cause of cancer deaths worldwide. Multimodality treatment includes surgery, chemotherapy, and targeted therapies with selective utilization of immunotherapy and radiation therapy. Despite the early success of anti-epidermal growth factor receptor (anti-EGFR) therapy, treatment resistance is common and often driven by mutations in APC, KRAS, RAF, and PI3K/mTOR and positive feedback between activated KRAS and WNT effectors. Challenges in the direct targeting of WNT regulators and KRAS have caused alternative actionable targets to gain recent attention. Utilizing an unbiased drug screen, we identified combinatorial targeting of DDR1/BCR-ABL signaling axis with small-molecule inhibitors of EGFR-ERBB2 to be potentially cytotoxic against multicellular spheroids obtained from WNT-activated and KRAS-mutant COAD lines (HCT116, DLD1, and SW480) independent of their KRAS mutation type. Based on the data-driven approach using available patient datasets (The Cancer Genome Atlas (TCGA)), we constructed transcriptomic correlations between gene DDR1, with an expression of genes for EGFR, ERBB2-4, mitogen-activated protein kinase (MAPK) pathway intermediates, BCR, and ABL and genes for cancer stem cell reactivation, cell polarity, and adhesion; we identified a positive association of DDR1 with EGFR, ERBB2, BRAF, SOX9, and VANGL2 in Pan-Cancer. The evaluation of the pathway network using the STRING database and Pathway Commons database revealed DDR1 protein to relay its signaling via adaptor proteins (SHC1, GRB2, and SOS1) and BCR axis to contribute to the KRAS-PI3K-AKT signaling cascade, which was confirmed by Western blotting. We further confirmed the cytotoxic potential of our lead combination involving EGFR/ERBB2 inhibitor (lapatinib) with DDR1/BCR-ABL inhibitor (nilotinib) in radioresistant spheroids of HCT116 (COAD) and, in an additional devastating primary cancer model, glioblastoma (GBM). GBMs overexpress DDR1 and share some common genomic features with COAD like EGFR amplification and WNT activation. Moreover, genetic alterations in genes like NF1 make GBMs have an intrinsically high KRAS activity. We show the combination of nilotinib plus lapatinib to exhibit more potent cytotoxic efficacy than either of the drugs administered alone in tumoroids of patient-derived recurrent GBMs. Collectively, our findings suggest that combinatorial targeting of DDR1/BCR-ABL with EGFR-ERBB2 signaling may offer a therapeutic strategy against stem-like KRAS-driven chemoradioresistant tumors of COAD and GBM, widening the window for its applications in mainstream cancer therapeutics.

Oxidative stress as a candidate mechanism for accelerated neuroectodermal differentiation due to trisomy 21.

The ubiquity of cognitive deficits and early onset Alzheimer's disease in Down syndrome (DS) has focused much DS iPSC-based research on neuron degeneration and regeneration. Despite reports of elevated oxidative stress in DS brains, few studies assess the impact of this oxidative burden on iPSC differentiation. Here, we evaluate cellular specific redox differences in DS and euploid iPSCs and neural progenitor cells (NPCs) during critical intermediate stages of differentiation. Despite successful generation of NPCs, our results indicate accelerated neuroectodermal differentiation of DS iPSCs compared to isogenic, euploid controls. Specifically, DS embryoid bodies (EBs) and neural rosettes prematurely develop with distinct morphological differences from controls. Additionally, we observed developmental stage-specific alterations in mitochondrial superoxide production and SOD1/2 abundance, coupled with modulations in thioredoxin, thioredoxin reductase, and peroxiredoxin isoforms. Disruption of intracellular redox state and its associated signaling has the potential to disrupt cellular differentiation and development in DS lending to DS-specific phenotypes.

WNT5A Interacts With FZD5 and LRP5 to Regulate Proliferation and Self-Renewal of Endometrial Mesenchymal Stem-Like Cells.

Endometrial mesenchymal stem-like cells (eMSC) reside in the basal layer of the endometrium and are responsible for cyclic regeneration during the reproductive lives of women. Myometrial cells act as a component of the niche and regulate the stem cell fate through the activation of WNT/ß-catenin signaling via WNT5A. Since WNT5A-responsive mechanisms on eMSC are still uncertain, we hypothesize that the WNT ligand-WNT5A works to activate WNT/ß-catenin signaling through binding to Frizzled receptors (FZDs) and co-receptor low-density lipoprotein receptor-related protein 5 (LRP5). Among the various receptors that have been reported to interact with WNT5A, we found FZD5 abundantly expressed by eMSC when compared to unfractionated stromal cells. Neutralizing the protein expression by using anti-FZD5 antibody suppressed the stimulatory effects on phenotypic expression and the clonogenicity of eMSC in a myometrial cell-eMSC co-culture system as well as in an L-Wnt5a conditioned medium. Gene silencing of FZD5 not only reduced the binding of WNT5A to eMSC but also decreased the TCF/LEF transcriptional activities and expression of active ß-catenin. Inhibition of LRP coreceptors with recombinant Dickkopf-1 protein significantly reduced the binding affinity of eMSC to WNT5A as well as the proliferation and self-renewal activity. During postpartum remodeling in mouse endometrium, active ß-catenin (ABC) was detected in label-retaining stromal cells (LRSCs), and these ABC+ LRSCs express FZD5 and LRP5, suggesting the activation of WNT/ß-catenin signaling. In conclusion, our findings demonstrate the interaction of WNT5A, FZD5, and LRP5 in regulating the proliferation and self-renewal of eMSC through WNT/ß-catenin signaling.

Estrogen Receptor 1 Inhibition of Wnt/ß-Catenin Signaling Contributes to Sex Differences in Hepatocarcinogenesis.

BACKGROUND: Hepatocellular Carcinoma (HCC) is a sexually dimorphic cancer, with female sex being independently protective against HCC incidence and progression. The aim of our study was to understand the mechanism of estrogen receptor signaling in driving sex differences in hepatocarcinogenesis. METHODS: We integrated 1,268 HCC patient sample profiles from publicly available gene expression data to identify the most differentially expressed genes (DEGs). We mapped DEGs into a physical protein interaction network and performed network topology analysis to identify the most important proteins. Experimental validation was performed in vitro on HCC cell lines, in and in vivo, using HCC mouse model. RESULTS: We showed that the most central protein, ESR1, is HCC prognostic, as increased ESR1 expression was protective for overall survival, with HR=0.45 (95%CI 0.32-0.64, p=4.4E-06), and was more pronounced in women. Transfection of HCC cell lines with ESR1 and exposure to estradiol affected expression of genes involved in the Wnt/ß-catenin signaling pathway. ER-α (protein product of ESR1) agonist treatment in a mouse model of HCC resulted in significantly longer survival and decreased tumor burden (p<0.0001), with inhibition of Wnt/ß-Catenin signaling. In vitro experiments confirmed colocalization of ß-catenin with ER-α, leading to inhibition of ß-catenin-mediated transcription of target genes c-Myc and Cyclin D1. CONCLUSION: Combined, the centrality of ESR1 and its inhibition of the Wnt/ß-catenin signaling axis provide a biological rationale for protection against HCC incidence and progression in women.