Wnt Activation Research Articles

Abstract 3163: (Phospho)proteomic analysis reveals vulnerabilities in refractory metastatic colorectal cancer

Abstract Proteomic networks are crucial for cellular homeostasis maintenance and, indeed, their aberrant regulation is implicated in cancer development and progression. Understanding alterations underlying these pathways, provides a way to design therapeutic interventions in human cancer. Improvements in mass spectrometry analysis have unlocked our potential to unveil cancer vulnerabilities. Here, we performed (phospho)proteomic analysis and ex-vivo drug testing on a cohort of refractory metastatic colorectal cancer (mCRC) tissues and matched patients-Derived Organoids (PDO) to identify new putative druggable biomarkers. The comparison between the proteome and phosphoproteome of 10 mCRCs tissues with their matched PDOs normalized to a pool of 6 colon mucosa tissues highlighted a strong overall correlation (R= 0.57 and R=0.6, respectively) suggesting a good level of similarity. Applying GSEA on our proteomic dataset, we identified up-regulation in MYC, cell cycle and MTORC1 signaling pathways in mCRC tissues and PDO, while kinase enrichment analysis highlighted an increase in Casein Kinase II (CKII) activity, an important cell cycle regulator. Our ex-vivo experiments showed that silmitasertib-mediated CKII inhibition reduced the cell viability in our PDO models, but with an overall modest effect. Analysis revealed that, even though not statistically significant, high Wnt signaling score correlated with an higher resistance to silmitasertib treatment (R=0.61; p=0.08). Previous works highlighted that MAPK activity is increased after silmitasertib treatment and responsible for resistance mechanisms to CKII inhibition. Strikingly, the combined trametinib-mediated MEK blockade and CKII blockade resulted in a synergistic interaction leading to enhanced antitumor activity, especially in PDO harboring high Wnt (R=0.74; p=0.022) and cell cycle (R=0.69; p=0.04) pathway activity. Moreover, the combined treatment strongly reduced S6 activity and RAPTOR expression, overcoming the significant effect exerted by the single agents. Surprisingly, none of them altered baseline MAPK activity, suggesting that silmitasertib and trametinib synergize their activity via inactivating the MTORC1-S6 axis in an ERK-independent manner. We are currently integrating genomic and transcriptomic data to better characterize the observed drug synergy. Taken together, our findings propose the silmitasertib and trametinib combination as a new therapeutic opportunity for refractory mCRC patients and strengthen the use of PDO as a suitable model for drug screening. Citation Format: Mattia Marinucci, Gina Faye Boot, Lara Zaidi, Cinzia Esposito, Mairene Coto Llerena, Savas Soysal, Otto Kolmar, Charlotte K Y Ng, Salvatore Piscuoglio. (Phospho)proteomic analysis reveals vulnerabilities in refractory metastatic colorectal cancer [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 3163.

Abstract 5840: Identifying drug tolerant persister to neoadjuvant osimertinib in resectable non-small cell lung cancer harbouring EGFR mutations (NORA) via single-cell RNA sequencing

Abstract Introduction: Adjuvant osimertinib is the standard of care for resected, stage IB-IIIA non-small cell lung cancer (NSCLC) harboring activating epidermal growth factor receptor (EGFR) mutation. Yet, the role of neoadjuvant osimertinib is not clear. In the NORA trial (NCT04816838), we aimed to identify the drug tolerant persister (DTP) after neoadjuvant osimertinib for surgically resectable, EGFR-mutated stage IA-IIIA NSCLC. Methods: Patients harboring EGFR Exon 19 deletion or L858R at clinical stage IA-IIIA were given 80 mg of neoadjuvant osimertinib daily for two 28-day cycles followed by surgical resection and adjuvant osimertinib for 3 years. The key exploratory endpoint was to characterize the DTP via single-cell RNA sequencing (scRNA-seq) with pre and post-osimertinib samples. Results: We performed scRNA-seq on twenty-five patients enrolled at Yonsei Cancer Center from June 2021 to March 2022. Patients with stage IA (n=8, 32%), IB (n=7, 28%), IIA (n=4, 16%), IIB (n=4, 16%), and IIIA (n=2, 8%) were included. For EGFR mutation, exon 19 del and L858R accounted for 10 (40%) patients and 15 (60%) patients, respectively. The ORR (all partial response) was 44% (n=11), major pathologic response (MPR) rate was 24% (n=6), and pathologic complete response rate was 0%. ScRNA-seq revealed a total of 252,339 cells (60 clusters) annotated as epithelial cells (10 clusters), fibroblasts (7 clusters), immune cells (17 clusters), myeloid (15 clusters), endothelial cells (11 clusters) that showed distinct enrichment in post-osimertinib samples, non-MPR, and L858R subset. We found that a distint epithelial subset, namely EP8-AGER, identified as alveolar type 1 (AT1) cells was enriched in the non-MPR subset showing activation of Wnt, Hippo, and YAP/TAZ pathway. Pseudotemporal ordering of this cluster showed activation of signaling pathway for COL4A2/COL4A3 related to structural consistuent of extracellular matrix, and RTKN2 associated with NF-κB. In the fibroblast subset, the proportion of FB6-CD74 associated with chemokine activity and NF-κB was higher in the non-MPR and L858R group. In the myeloid subset, CD8-C1-GZMK identified as CD8+ T cells with activation/effector and cytotoxic signatures was also enriched in the post-osimertinib samples. Among macrophages, 3 clusters (annotated as SELENOP+, SPP1+, PLXDC2+) showed enrichment of cholesterol metabolism with activation of apolipoprotein E that promotes conversion of proinflammatory macrophages into anti-inflammatory phenotypes. Lastly, the proportion of EC9-LYZ, annotated as scavenging endothelial cells was higher in the non-MPR and L858R group. Conclusion: Neoadjuvant osimertinib resulted in the cellular reprogramming in the tumor microenvironment, notably AT1 epithelial cell which may lead to a loop between cancer cells and fibroblasts for the generation of DTP cells. Citation Format: Jii Bum (Joy) Lee, Su-Jin Choi, Young Joon Park, Kyoung-Ho Park, Seung Hyun Yong, Hyo Sup Shim, Byung Jo Park, Chang Young Lee, Min Hee Hong, Byoung Chul Cho, Sun Min Lim. Identifying drug tolerant persister to neoadjuvant osimertinib in resectable non-small cell lung cancer harbouring EGFR mutations (NORA) via single-cell RNA sequencing [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 5840.

Mice with renal-specific alterations of stem cell-associated signaling develop symptoms of chronic kidney disease but surprisingly no tumors.

Previously, we found that Wnt and Notch signaling govern stem cells of clear cell kidney cancer (ccRCC) in patients. To mimic stem cell responses in the normal kidney in vitro in a marker-unbiased fashion, we have established tubular organoids (tubuloids) from total single adult mouse kidney epithelial cells in Matrigel and serum-free conditions. Deep proteomic and phosphoproteomic analyses revealed that tubuloids resembled renewal of adult kidney tubular epithelia, since tubuloid cells displayed activity of Wnt and Notch signaling, long-term proliferation and expression of markers of proximal and distal nephron lineages. In our wish to model stem cell-derived human ccRCC, we have generated two types of genetic double kidney mutants in mice: Wnt-β-catenin-GOF together with Notch-GOF and Wnt-β-catenin-GOF together with a most common alteration in ccRCC, Vhl-LOF. An inducible Pax8-rtTA-LC1-Cre was used to drive recombination specifically in adult kidney epithelial cells. We confirmed mutagenesis of β-catenin, Notch and Vhl alleles on DNA, protein and mRNA target gene levels. Surprisingly, we observed symptoms of chronic kidney disease (CKD) in mutant mice, but no increased proliferation and tumorigenesis. Thus, the responses of kidney stem cells in the tubuloid and genetic systems produced different phenotypes, i.e. enhanced renewal versus CKD.

Competence for neural crest induction is controlled by hydrostatic pressure through Yap

Embryonic induction is a key mechanism in development that corresponds to an interaction between a signalling and a responding tissue, causing a change in the direction of differentiation by the responding tissue. Considerable progress has been achieved in identifying inductive signals, yet how tissues control their responsiveness to these signals, known as competence, remains poorly understood. While the role of molecular signals in competence has been studied, how tissue mechanics influence competence remains unexplored. Here we investigate the role of hydrostatic pressure in controlling competence in neural crest cells, an embryonic cell population. We show that neural crest competence decreases concomitantly with an increase in the hydrostatic pressure of the blastocoel, an embryonic cavity in contact with the prospective neural crest. By manipulating hydrostatic pressure in vivo, we show that this increase leads to the inhibition of Yap signalling and impairs Wnt activation in the responding tissue, which would be required for neural crest induction. We further show that hydrostatic pressure controls neural crest induction in amphibian and mouse embryos and in human cells, suggesting a conserved mechanism across vertebrates. Our work sets out how tissue mechanics can interplay with signalling pathways to regulate embryonic competence.

O189: Exploring the polyclonal origins of intestinal tumours

Abstract Introduction Some reports have shown that a proportion of intestinal tumours in the human colorectal cancer (CRC) predisposition syndrome Familial Adenomatous Polyposis (FAP) may have a multi-ancestral structure, challenging the widely-held monoclonal theory of tumour initiation. The nature of these polyclonal tumours and the reasons for their existence have not yet been elucidated. Methods Intestinal tumorigenesis was promoted through chemical mutagenesis in Villin-CreERT2-Apcfl/+ mice containing a multicolour reporter. The clonal status of tumours was determined with confocal microscopy. Targeted cancer driver sequencing was performed to determine if certain driver mutations were associated with monoclonal or polyclonal routes of tumour formation. Finally, transcriptomic analysis was performed to identify differentially expressed pathways. Results Confocal imaging reveals that more than 40% of tumours are heterotypic, and therefore polyclonal. Transcriptomic profiling of clones within these tumours demonstrates a non-cell autonomous interplay between Myc and Ras pathways, suggestive of oncogenic cooperation between adjacent clones. Strikingly, sequencing reveals that the nature of the Apc mutation dictates clonal architecture. Using a large publicly available dataset of sporadic CRCs, these mutational differences are confirmed, suggesting a role for differential Wnt activation in tumour initiation. Conclusions Taken together, these data suggest that a significant proportion of intestinal tumours arise through clonal cooperation, and that early RAS/MAPK pathway activation may obviate the need for this. Clonal cooperation appears to be at play not just in FAP but also in sporadic CRCs. Uncovering this mechanism may pave the way for therapeutics aimed at reducing tumour burden in patients with FAP.

Mechanical loading rescues mechanoresponsiveness in a human osteoarthritis explant model despite Wnt activation

ObjectivesOptimizing rehabilitation strategies for osteoarthritis necessitates a comprehensive understanding of chondrocytes’ mechanoresponse in both health and disease, especially in the context of the interplay between loading and key pathways involved in osteoarthritis development, like canonical Wnt signaling. This study aims to elucidate the role of Wnt signaling in the mechanoresponsiveness of healthy and osteoarthritic human cartilage. MethodsWe used an ex-vivo model involving short-term physiological mechanical loading of human cartilage explants. First, the loading protocol for subsequent experiments was determined. Next, loading was applied to non-OA explants with or without Wnt activation with CHIR99021. Molecular read-outs of anabolic, pericellular matrix and matrix remodeling markers were used to assess the effect of Wnt on cartilage mechanoresponse. Finally, the same set-up was used to study the effect of loading in cartilage from patients with established OA. ResultsOur results confirm that physiological loading maintains expression of anabolic genes in non-OA cartilage, and indicate a deleterious effect of Wnt activation in the chondrocyte mechanoresponsiveness. This suggests that loading-induced regulation of chondrocyte markers occurs downstream of canonical Wnt signaling. Interestingly, our study highlighted contrasting mechanoresponsiveness in the model of Wnt activation and the established OA samples, with established OA cartilage maintaining its mechanoresponsiveness, and mechanical loading rescuing the chondrogenic phenotype. ConclusionThis study provides insights into the mechanoresponsiveness of human cartilage in both non-OA and OA conditions. These findings hold the potential to contribute to the development of strategies that optimize the effect of dynamic compression by correcting OA pathological cell signaling.

Nanotechnological Advancements for the Theranostic Intervention in Anaplastic Thyroid Cancer: Current Perspectives and Future Direction.

Anaplastic thyroid cancer is the rarest, most aggressive, and undifferentiated class of thyroid cancer, accounting for nearly forty percent of all thyroid cancer-related deaths. It is caused by alterations in many cellular pathways like MAPK, PI3K/AKT/mTOR, ALK, Wnt activation, and TP53 inactivation. Although many treatment strategies, such as radiation therapy and chemotherapy, have been proposed to treat anaplastic thyroid carcinoma, they are usually accompanied by concerns such as resistance, which may lead to the lethality of the patient. The emerging nanotechnology-based approaches cater the purposes such as targeted drug delivery and modulation in drug release patterns based on internal or external stimuli, leading to an increase in drug concentration at the site of the action that gives the required therapeutic action as well as modulation in diagnostic intervention with the help of dye property materials. Nanotechnological platforms like liposomes, micelles, dendrimers, exosomes, and various nanoparticles are available and are of high research interest for therapeutic intervention in anaplastic thyroid cancer. The pro gression of the disease can also be traced by using magnetic probes or radio-labeled probes and quantum dots that serve as a diagnostic intervention in anaplastic thyroid cancer.

NEK2 plays an essential role in porcine embryonic development by maintaining mitotic division and DNA damage response via the Wnt/β-catenin signalling pathway.

NIMA-related kinase 2 (NEK2) is a serine/threonine protein kinase that regulates mitosis and plays pivotal roles in cell cycle regulation and DNA damage repair. However, its function in porcine embryonic development is unknown. In this study, we used an NEK2-specific inhibitor, JH295 (JH), to investigate the role of NEK2 in embryonic development and the underlying regulatory mechanisms. Inhibition of NEK2 after parthenogenesis activation or in vitro fertilization significantly reduced the rates of cleavage and blastocyst formation, the numbers of trophectoderm and total cells and the cellular survival rate compared with the control condition. NEK2 inhibition delayed cell cycle progression at all stages from interphase to cytokinesis during the first mitotic division; it caused abnormal nuclear morphology in two- and four-cell stage embryos. Additionally, NEK2 inhibition significantly increased DNA damage and apoptosis, and it altered the expression levels of DNA damage repair- and apoptosis-related genes. Intriguingly, NEK2 inhibition downregulated the expression of β-catenin and its downstream target genes. To validate the relationship between Wnt/β-catenin signalling and NEK2 during porcine embryonic development, we cultured porcine embryos in JH-treated medium with or without CHIR99021, a Wnt activator. CHIR99021 co-treatment strongly restored the developmental parameters reduced by NEK2 inhibition to control levels. Our findings suggest that NEK2 plays an essential role in porcine embryonic development by regulating DNA damage repair and normal mitotic division via the Wnt/β-catenin signalling pathway.

RhoA downregulation in the murine intestinal epithelium results in chronic Wnt activation and increased tumorigenesis

RhoA downregulation in the murine intestinal epithelium results in chronic Wnt activation and increased tumorigenesis

Unravelling the Road to Recovery: Mechanisms of Wnt Signalling in Spinal Cord Injury.

Spinal cord injury (SCI) is a complex neurodegenerative pathology that consistently harbours a poor prognostic outcome. At present, there are few therapeutic strategies that can halt neuronal cell death and facilitate functional motor recovery. However, recent studies have highlighted the Wnt pathway as a key promoter of axon regeneration following central nervous system (CNS) injuries. Emerging evidence also suggests that the temporal dysregulation of Wnt may drive cell death post-SCI. A major challenge in SCI treatment resides in developing therapeutics that can effectively target inflammation and facilitate glial scar repair. Before Wnt signalling is exploited for SCI therapy, further research is needed to clarify the implications of Wnt on neuroinflammation during chronic stages of injury. In this review, an attempt is made to dissect the impact of canonical and non-canonical Wnt pathways in relation to individual aspects of glial and fibrotic scar formation. Furthermore, it is also highlighted how modulating Wnt activity at chronic time points may aid in limiting lesion expansion and promoting axonal repair.

Perturbed liver gene zonation in a mouse model of non-alcoholic steatohepatitis

Liver zonation characterizes the separation of metabolic pathways along the lobules and is required for optimal hepatic function. Wnt signaling is a master regulator of spatial liver zonation. A perivenous-periportal Wnt activity gradient orchestrates metabolic zonation by activating gene expression in perivenous hepatocytes, while suppressing gene expression in their periportal counterparts. However, the understanding as to the liver gene zonation and zonation regulators in diseases is limited. Non-alcoholic steatohepatitis (NASH) is a chronic liver disease characterized by fat accumulation, inflammation, and fibrosis. Here, we investigated the perturbation of liver gene zonation in a mouse NASH model by combining spatial transcriptomics, bulk RNAseq and in situ hybridization. Wnt-target genes represented a major subset of genes showing altered spatial expression in the NASH liver. The altered Wnt-target gene expression levels and zonation spatial patterns were in line with the up regulation of Wnt regulators and the augmentation of Wnt signaling. Particularly, we found that the Wnt activator Rspo3 expression was restricted to the perivenous zone in control liver but expanded to the periportal zone in NASH liver. AAV8-mediated RSPO3 overexpression in controls resulted in zonation changes, and further amplified the disturbed zonation of Wnt-target genes in NASH, similarly Rspo3 knockdown in Rspo3+/− mice resulted in zonation changes of Wnt-target genes in both chow and HFD mouse. Interestingly, there were no impacts on steatosis, inflammation, or fibrosis NASH pathology from RSPO3 overexpression nor Rspo3 knockdown. In summary, our study demonstrated the alteration of Wnt signaling in a mouse NASH model, leading to perturbed liver zonation.

A Protective Role of Canonical Wnt/β-Catenin Pathway in Pathogenic Bacteria-Induced Inflammatory Responses.

Inflammation is a complex host defensive response against various disease-associated pathogens. A baseline extent of inflammation is supposed to be tightly associated with a sequence of immune-modulated processes, resulting in the protection of the host organism against pathogen invasion; however, as a matter of fact is that an uncontrolled inflammatory cascade is the main factor responsible for the host damage, accordingly suggesting a significant and indispensable involvement of negative feedback mechanism in modulation of inflammation. Evidence accumulated so far has supported a repressive effect of the canonical Wnt/β-catenin pathway on microbial-triggered inflammation via diverse mechanisms, although that consequence is dependent on the cellular context, types of stimuli, and cytokine environment. It is of particular interest and importance to comprehend the precise way in which the Wnt/β-catenin pathway is activated, due to its essential anti-inflammatory properties. It is assumed that an inflammatory milieu is necessary for initiating and activating this signaling, implying that Wnt activity is responsible for shielding tissues from overwhelming inflammation, thus sustaining a balanced physiological condition against bacterial infection. This review gathers the recent efforts to elucidate the mechanistic details through how Wnt/β-catenin signaling modulates anti-inflammatory responses in response to bacterial infection and its interactions with other inflammatory signals, which warrants further study for the development of specific interventions for the treatment of inflammatory diseases. Further clinical trials from different disease settings are required.

Crosstalk between Wnt and bone morphogenetic protein signaling during osteogenic differentiation.

Mesenchymal stem cells (MSCs) originate from many sources, including the bone marrow and adipose tissue, and differentiate into various cell types, such as osteoblasts and adipocytes. Recent studies on MSCs have revealed that many transcription factors and signaling pathways control osteogenic development. Osteogenesis is the process by which new bones are formed; it also aids in bone remodeling. Wnt/β-catenin and bone morphogenetic protein (BMP) signaling pathways are involved in many cellular processes and considered to be essential for life. Wnt/β-catenin and BMPs are important for bone formation in mammalian development and various regulatory activities in the body. Recent studies have indicated that these two signaling pathways contribute to osteogenic differentiation. Active Wnt signaling pathway promotes osteogenesis by activating the downstream targets of the BMP signaling pathway. Here, we briefly review the molecular processes underlying the crosstalk between these two pathways and explain their participation in osteogenic differentiation, emphasizing the canonical pathways. This review also discusses the crosstalk mechanisms of Wnt/BMP signaling with Notch- and extracellular-regulated kinases in osteogenic differentiation and bone development.

SOX9 switch links regeneration to fibrosis at the single-cell level in mammalian kidneys.

The steps governing healing with or without fibrosis within the same microenvironment are unclear. After acute kidney injury (AKI), injured proximal tubular epithelial cells activate SOX9 for self-restoration. Using a multimodal approach for a head-to-head comparison of injury-induced SOX9 lineages, we identified a dynamic SOX9 switch in repairing epithelia. Lineages that regenerated epithelia silenced SOX9 and healed without fibrosis (SOX9on-off). By contrast, lineages with unrestored apicobasal polarity maintained SOX9 activity in sustained efforts to regenerate, which were identified as a SOX9on-on Cadherin6pos cell state. These reprogrammed cells generated substantial single-cell WNT activity to provoke a fibroproliferative response in adjacent fibroblasts, driving AKI to chronic kidney disease. Transplanted human kidneys displayed similar SOX9/CDH6/WNT2B responses. Thus, we have uncovered a sensor of epithelial repair status, the activity of which determines regeneration with or without fibrosis.

Exploring the dynamics of adult Axin2 cell lineage integration into dentate gyrus granule neurons.

The Wnt pathway plays critical roles in neurogenesis. The expression of Axin2 is induced by Wnt/β-catenin signaling, making this gene a reliable indicator of canonical Wnt activity. We employed pulse-chase genetic lineage tracing with the Axin2-CreERT2 allele to follow the fate of Axin2+ lineage in the adult hippocampal formation. We found Axin2 expressed in astrocytes, neurons and endothelial cells, as well as in the choroid plexus epithelia. Simultaneously with the induction of Axin2 fate mapping by tamoxifen, we marked the dividing cells with 5-ethynyl-2'-deoxyuridine (EdU). Tamoxifen induction led to a significant increase in labeled dentate gyrus granule cells three months later. However, none of these neurons showed any EdU signal. Conversely, six months after the pulse-chase labeling with tamoxifen/EdU, we identified granule neurons that were positive for both EdU and tdTomato lineage tracer in each animal. Our data indicates that Axin2 is expressed at multiple stages of adult granule neuron differentiation. Furthermore, these findings suggest that the integration process of adult-born neurons from specific cell lineages may require more time than previously thought.

A growth factor-reduced culture system for colorectal cancer organoids

Although organoids derived from tumor tissues have been widely used in cancer research, it is a great challenge for cultured organoids to retain the characteristics of the original tumor tissues due to their heterogeneity. In this study, we explore organoid culture recipes to capture tumor features of colorectal cancers. We find that the activation of Wnt and EGF signaling and inhibition of BMP signaling are non-essential for the survival of most colorectal cancer organoids (CRCOs). We design a growth factor-reduced culture medium containing FGF10, A83-01 (TGF-β type I receptor inhibitor), SB202190 (p38 MAPK inhibitor), gastrin, and nicotinamide. Using this medium, we can maintain tumor features in long-term CRCO cultivation, as evidenced by histopathology, genetic stability, tumorigenicity, and response of clinical treatments. Our findings offer a reliable and economical strategy for CRCO culture, facilitating the utilization of organoids in colorectal cancer research and treatment.

Correlation between intestinal stem cell niche changes and small bowel crypt failure in patients with treatment-naïve celiac disease.

We hypothesized that crypt failure in the small bowel results in villous flattening in patients with celiac disease (CeD). We investigated whether alterations in the stem cell niche (ISC) are responsible for this phenomenon. We included 92 duodenal (D2/3) biopsies from treatment-naive patients of CeD and 37 controls. All underwent screening for serum anti-tissue transglutaminase and endoscopic upper small bowel biopsy. Immunohistochemical markers were used to investigate ISC niche alterations, including LGR5 for crypt basal cells (CBC), Bmi1 for position 4+ cells, β-Defensin for Paneth cells, R-spondin1 as WNT activator, transcription factor-4 as WNT transcription factor, BMP receptor1A as WNT inhibitor, fibronectin-1 as periepithelial stromal cell marker, H2AX as apoptosis marker, and Ki67 as proliferation marker. We also analyzed IgA anti-tTG2 antibody deposits by using dual-color immunofluorescence staining. We found that in biopsies from patients with treatment-naive CeD with modified Marsh grade 3a-3c changes, the epithelial H2AX apoptotic index was upregulated than in controls. LGR5+ crypt basal cells were upregulated in all modified Marsh grades compared to controls. However, the Ki67 proliferation index, expressions of WNT-activator RSPO1, and position-4 cell marker Bmi1 did not significantly alter in patients' biopsies as compared to controls ( P = 0.001). We also observed depletion of pericrypt stromal fibronectin-1 in patients with CeD compared to controls. In addition, we identified IgA anti-TG2 antibody deposits in pericrypt stroma. Our data suggests that ISC niche failure is a plausible hypothesis for villous flattening in patients with CeD, resulting from pericrypt IgA anti-TG2 antibody complex-mediated stromal depletion.

Androgen deprivation induces double-null prostate cancer via aberrant nuclear export and ribosomal biogenesis through HGF and Wnt activation

Androgen deprivation therapy (ADT) targeting androgen/androgen receptor (AR)- signaling pathways is the main therapy for advanced prostate cancer (PCa). However, ADT eventually fails in most patients who consequently develop castration-resistant prostate cancer (CRPC). While more potent AR antagonists and blockers for androgen synthesis were developed to improve clinical outcomes, they also show to induce more diverse CRPC phenotypes. Specifically, the AR- and neuroendocrine-null PCa, DNPC, occurs in abiraterone and enzalutamide-treated patients. Here, we uncover that current ADT induces aberrant HGF/MET signaling activation that further elevates Wnt/β-catenin signaling in human DNPC samples. Co-activation of HGF/MET and Wnt/β-catenin axes in mouse prostates induces DNPC-like lesions. Single-cell RNA sequencing analyses identify increased expression and activity of XPO1 and ribosomal proteins in mouse DNPC-like cells. Elevated expression of XPO1 and ribosomal proteins is also identified in clinical DNPC specimens. Inhibition of XPO1 and ribosomal pathways represses DNPC growth in both in vivo and ex vivo conditions, evidencing future therapeutic targets.

Lung endothelium exploits susceptible tumor cell states to instruct metastatic latency

In metastasis, cancer cells travel around the circulation to colonize distant sites. Due to the rarity of these events, the immediate fates of metastasizing tumor cells (mTCs) are poorly understood while the role of the endothelium as a dissemination interface remains elusive. Using a newly developed combinatorial mTC enrichment approach, we provide a transcriptional blueprint of the early colonization process. Following their arrest at the metastatic site, mTCs were found to either proliferate intravascularly or extravasate, thereby establishing metastatic latency. Endothelial-derived angiocrine Wnt factors drive this bifurcation, instructing mTCs to follow the extravasation–latency route. Surprisingly, mTC responsiveness towards niche-derived Wnt was established at the epigenetic level, which predetermined tumor cell behavior. Whereas hypomethylation enabled high Wnt activity leading to metastatic latency, methylated mTCs exhibited low activity and proliferated intravascularly. Collectively the data identify the predetermined methylation status of disseminated tumor cells as a key regulator of mTC behavior in the metastatic niche.

Conserved and divergent features of trophoblast stem cells.

Trophoblast stem cells (TSCs) are a proliferative multipotent population derived from the trophectoderm of the blastocyst, which will give rise to all the functional cell types of the trophoblast compartment of the placenta. The isolation and culture of TSCs in vitro represent a robust model to study mechanisms of trophoblast differentiation into mature cells both in successful and diseased pregnancy. Despite the highly conserved functions of the placenta, there is extreme variability in placental morphology, fetal-maternal interface, and development among eutherian mammals. This review aims to summarize the establishment and maintenance of TSCs in mammals such as primates, including human, rodents, and nontraditional animal models with a primary emphasis on epigenetic regulation of their origin while defining gaps in the current literature and areas of further development. FGF signaling is critical for mouse TSCs but dispensable for derivation of TSCs in other species. Human, simian, and bovine TSCs have much more complicated requirements of signaling pathways including activation of WNT and inhibition of TGFβ cascades. Epigenetic features such as DNA and histone methylation as well as histone acetylation are dynamic during development and are expressed in cell- and gestational age-specific pattern in placental trophoblasts. While TSCs from different species seem to recapitulate some select epigenomic features, there is a limitation in the comprehensive understanding of TSCs and how well TSCs retain placental epigenetic marks. Therefore, future studies should be directed at investigating epigenomic features of global and placental-specific gene expression in primary trophoblasts and TSCs.