Trophoblastic cell surface antigen 2 (TROP2) is a membrane glycoprotein overexpressed in many solid tumors with a poor prognosis, including intestinal neoplasms. In our study, we show that TROP2 is expressed in preneoplastic lesions, and its expression is maintained in most colorectal cancers (CRC). High TROP2 positivity correlated with lymph node metastases and poor tumor differentiation and was a negative prognostic factor. To investigate the role of TROP2 in intestinal tumors, we analyzed two mouse models with conditional disruption of the adenomatous polyposis coli (Apc) tumor-suppressor gene, human adenocarcinoma samples, patient-derived organoids, and TROP2-deficient tumor cells. We found that Trop2 is produced early after Apc inactivation and its expression is associated with the transcription of genes involved in epithelial-mesenchymal transition, the regulation of migration, invasiveness, and extracellular matrix remodeling. A functionally similar group of genes was also enriched in TROP2-positive cells from human CRC samples. To decipher the driving mechanism of TROP2 expression, we analyzed its promoter. In human cells, this promoter was activated by β-catenin and additionally by the Yes1-associated transcriptional regulator (YAP). The regulation of TROP2 expression by active YAP was verified by YAP knockdown in CRC cells. Our results suggest a possible link between aberrantly activated Wnt/β-catenin signaling, YAP, and TROP2 expression.
- Publikační typ
- časopisecké články MeSH
Modulating endogenous regenerative processes may represent a suitable treatment for central nervous system (CNS) injuries, such as stroke or trauma. Neural stem/progenitor cells (NS/PCs), which naturally reside in the subventricular zone (SVZ) of the adult brain, proliferate and differentiate to other cell types, and therefore may compensate the negative consequences of ischemic injury. The fate of NS/PCs in the developing brain is largely influenced by Wingless/Integrated (Wnt) signaling; however, its role in the differentiation of adult NS/PCs under ischemic conditions is still enigmatic. In our previous study, we identified the Wnt/β-catenin signaling pathway as a factor promoting neurogenesis at the expense of gliogenesis in neonatal mice. In this study, we used adult transgenic mice in order to assess the impact of the canonical Wnt pathway modulation (inhibition or hyper-activation) on NS/PCs derived from the SVZ, and combined it with the middle cerebral artery occlusion (MCAO) to disclose the effect of focal cerebral ischemia (FCI). Based on the electrophysiological properties of cultured cells, we first identified three cell types that represented in vitro differentiated NS/PCs - astrocytes, neuron-like cells, and precursor cells. Following FCI, we detected fewer neuron-like cells after Wnt signaling inhibition. Furthermore, the immunohistochemical analysis revealed an overall higher expression of cell-type-specific proteins after FCI, indicating increased proliferation and differentiation rates of NS/PCs in the SVZ. Remarkably, Wnt signaling hyper-activation increased the abundance of proliferating and neuron-like cells, while Wnt pathway inhibition had the opposite effect. Finally, the expression profiling at the single cell level revealed an increased proportion of neural stem cells and neuroblasts after FCI. These observations indicate that Wnt signaling enhances NS/PCs-based regeneration in the adult mouse brain following FCI, and supports neuronal differentiation in the SVZ.
- Publikační typ
- časopisecké články MeSH
The first step in the development of human colorectal cancer is aberrant activation of the Wnt signaling pathway. Wnt signaling hyperactivation is predominantly caused by loss-of-function mutations in the adenomatous polyposis coli (APC) gene that encodes the pathway negative regulator. In order to identify genes affected by the Apc loss, we performed expression profiling of intestinal epithelium isolated from mice harboring a conditional Apc allele. The gene encoding transcriptional factor msh homeobox 1 (Msx1) displayed robust upregulation upon Apc inactivation. Histological analysis of the Apc-deficient epithelium revealed that in the small intestine, the Msx1 protein was localized exclusively in ectopic crypts, i.e., in pockets of proliferating cells abnormally positioned on the villi. Ablation of the Msx1 gene leads to the disappearance of ectopic crypts and loss of differentiated cells. Moreover, tumors arising from Msx1-deficient cells display altered morphology reminiscent of villous adenomas. In human tumor specimens, MSX1 displayed significantly increased expression in colonic neoplasia with a descending tendency during the lesion progression towards colorectal carcinoma. In summary, the results indicate that Msx1 represents a novel marker of intestinal tumorigenesis. In addition, we described the previously unknown relationship between the Msx1-dependent formation of ectopic crypts and cell differentiation.
- MeSH
- beta-katenin metabolismus MeSH
- buněčná diferenciace MeSH
- kolorektální nádory genetika patologie MeSH
- lidé MeSH
- myši knockoutované MeSH
- nádory tračníku genetika patologie MeSH
- protein familiární adenomatózní polypózy genetika metabolismus MeSH
- regulace genové exprese u nádorů MeSH
- signální dráha Wnt MeSH
- stanovení celkové genové exprese MeSH
- střevní sliznice metabolismus patologie MeSH
- tenké střevo patologie MeSH
- transkripční faktor MSX1 genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
T-cell factor 4 (TCF4), together with β-catenin coactivator, functions as the major transcriptional mediator of the canonical wingless/integrated (Wnt) signaling pathway in the intestinal epithelium. The pathway activity is essential for both intestinal homeostasis and tumorigenesis. To date, several mouse models and cellular systems have been used to analyze TCF4 function. However, some findings were conflicting, especially those that were related to the defects observed in the mouse gastrointestinal tract after Tcf4 gene deletion, or to a potential tumor suppressive role of the gene in intestinal cancer cells or tumors. Here, we present the results obtained using a newly generated conditional Tcf4 allele that allows inactivation of all potential Tcf4 isoforms in the mouse tissue or small intestinal and colon organoids. We also employed the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system to disrupt the TCF4 gene in human cells. We showed that in adult mice, epithelial expression of Tcf4 is indispensable for cell proliferation and tumor initiation. However, in human cells, the TCF4 role is redundant with the related T-cell factor 1 (TCF1) and lymphoid enhancer-binding factor 1 (LEF1) transcription factors.
- Publikační typ
- časopisecké články MeSH
Neoplastic growth is frequently associated with genomic DNA methylation that causes transcriptional silencing of tumor suppressor genes. We used a collection of colorectal polyps and carcinomas in combination with bioinformatics analysis of large datasets to study the expression and methylation of Hypermethylated in cancer 1 (HIC1), a tumor suppressor gene inactivated in many neoplasms. In premalignant stages, HIC1 expression was decreased, and the decrease was linked to methylation of a specific region in the HIC1 locus. However, in carcinomas, the HIC1 expression was variable and, in some specimens, comparable to healthy tissue. Importantly, high HIC1 production distinguished a specific type of chemotherapy-responsive tumors.
- Publikační typ
- časopisecké články MeSH
The Wnt pathway plays a crucial role in self-renewal and differentiation of cells in the adult gut. In the present study, we revealed the functional consequences of inhibition of canonical Wnt signaling in the intestinal epithelium. The study was based on generation of a novel transgenic mouse strain enabling inducible expression of an N-terminally truncated variant of nuclear Wnt effector T cell factor 4 (TCF4). The TCF4 variant acting as a dominant negative (dn) version of wild-type (wt) TCF4 protein decreased transcription of β-catenin-TCF4-responsive genes. Interestingly, suppression of Wnt/β-catenin signaling affected asymmetric division of intestinal stem cells (ISCs) rather than proliferation. ISCs expressing the transgene underwent several rounds of division but lost their clonogenic potential and migrated out of the crypt. Expression profiling of crypt cells revealed that besides ISC-specific markers, the dnTCF4 production downregulated expression levels of epithelial genes produced in other crypt cells including markers of Paneth cells. Additionally, in Apc conditional knockout mice, dnTCF activation efficiently suppressed growth of Apc-deficient tumors. In summary, the generated mouse strain represents a convenient tool to study cell-autonomous inhibition of β-catenin-Tcf-mediated transcription.
- MeSH
- beta-katenin metabolismus MeSH
- buněčná diferenciace MeSH
- buněčné dělení MeSH
- genetická transkripce MeSH
- kmenové buňky cytologie metabolismus MeSH
- myši transgenní MeSH
- myši MeSH
- proliferace buněk MeSH
- signální dráha Wnt * MeSH
- střevní sliznice cytologie metabolismus MeSH
- tenké střevo cytologie metabolismus MeSH
- transkripční faktory BHLH-Zip chemie genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The activity of the Wnt pathway undergoes complex regulation to ensure proper functioning of this principal signaling mechanism during development of adult tissues. The regulation may occur at several levels and includes both positive and negative feedback loops. In the present study we employed one of such negative feedback regulators, naked cuticle homolog 1 (Nkd1), to follow the Wnt pathway activity in the intestine and liver and in neoplasia originated in these organs. Using lineage tracing in transgenic mice we localized Nkd1 mRNA to the bottom parts of the small intestinal crypts and hepatocytes surrounding the central vein of the hepatic lobule. Furthermore, in two mouse models of intestinal tumorigenesis, Nkd1 expression levels were elevated in tumors when compared to healthy tissue. We utilized a collection of human intestinal polyps and carcinomas to confirm that NKD1 represents a robust marker of neoplastic growth. In addition, expression analysis of NKD1 in liver cancer showed that high expression levels of the gene distinguish a subclass of hepatocellular carcinomas related to aberrant Wnt signaling. Finally, our results were confirmed by bioinformatic analysis of large publicly available datasets that included gene expression profiling and high-throughput sequencing data of human colon and liver cancer specimens.
- MeSH
- beta-katenin genetika metabolismus MeSH
- genetická transkripce MeSH
- hepatocelulární karcinom metabolismus patologie MeSH
- hepatocyty metabolismus patologie MeSH
- kolorektální nádory metabolismus patologie MeSH
- lidé MeSH
- messenger RNA metabolismus MeSH
- mutace MeSH
- myši transgenní MeSH
- myši MeSH
- nádory jater metabolismus patologie MeSH
- protein familiární adenomatózní polypózy nedostatek genetika metabolismus MeSH
- proteiny Wnt metabolismus MeSH
- signální transdukce MeSH
- střevní nádory metabolismus patologie MeSH
- transportní proteiny genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
UNLABELLED: Hypermethylated in cancer 1 (HIC1) represents a prototypic tumor suppressor gene frequently inactivated by DNA methylation in many types of solid tumors. The gene encodes a sequence-specific transcriptional repressor controlling expression of several genes involved in cell cycle or stress control. In this study, a Hic1 allele was conditionally deleted, using a Cre/loxP system, to identify genes influenced by the loss of Hic1. One of the transcripts upregulated upon Hic1 ablation is the toll-like receptor 2 (TLR2). Tlr2 expression levels increased in Hic1-deficient mouse embryonic fibroblasts (MEF) and cultured intestinal organoids or in human cells upon HIC1 knockdown. In addition, HIC1 associated with the TLR2 gene regulatory elements, as detected by chromatin immunoprecipitation, indicating that Tlr2 indeed represents a direct Hic1 target. The Tlr2 receptor senses "danger" signals of microbial or endogenous origin to trigger multiple signaling pathways, including NF-κB signaling. Interestingly, Hic1 deficiency promoted NF-κB pathway activity not only in cells stimulated with Tlr2 ligand, but also in cells treated with NF-κB activators that stimulate different surface receptors. In the intestine, Hic1 is mainly expressed in differentiated epithelial cells and its ablation leads to increased Tlr2 production. Finally, in a chemical-induced mouse model of carcinogenesis, Hic1 absence resulted in larger Tlr2-positive colonic tumors that showed increased proportion of proliferating cells. IMPLICATIONS: The tumor-suppressive function of Hic1 in colon is related to its inhibitory action on proproliferative signaling mediated by the Tlr2 receptor present on tumor cells.
- MeSH
- azoxymethan MeSH
- epitelové buňky MeSH
- genový knockdown MeSH
- karcinogeneze metabolismus MeSH
- lidé MeSH
- modely nemocí na zvířatech MeSH
- myši transgenní MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- nádorové supresorové proteiny metabolismus MeSH
- nádory tračníku MeSH
- NF-kappa B metabolismus MeSH
- proliferace buněk MeSH
- signální transdukce * MeSH
- síran dextranu MeSH
- střeva cytologie MeSH
- toll-like receptor 2 metabolismus MeSH
- transkripční faktory Krüppel-like genetika metabolismus MeSH
- upregulace MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The Wnt signaling pathway is required during embryonic development and for the maintenance of homeostasis in adult tissues. However, aberrant activation of the pathway is implicated in a number of human disorders, including cancer of the gastrointestinal tract, breast, liver, melanoma, and hematologic malignancies. In this study, we identified monensin, a polyether ionophore antibiotic, as a potent inhibitor of Wnt signaling. The inhibitory effect of monensin on the Wnt/β-catenin signaling cascade was observed in mammalian cells stimulated with Wnt ligands, glycogen synthase kinase-3 inhibitors, and in cells transfected with β-catenin expression constructs. Furthermore, monensin suppressed the Wnt-dependent tail fin regeneration in zebrafish and Wnt- or β-catenin-induced formation of secondary body axis in Xenopus embryos. In Wnt3a-activated HEK293 cells, monensin blocked the phoshorylation of Wnt coreceptor low-density lipoprotein receptor related protein 6 and promoted its degradation. In human colorectal carcinoma cells displaying deregulated Wnt signaling, monensin reduced the intracellular levels of β-catenin. The reduction attenuated the expression of Wnt signaling target genes such as cyclin D1 and SP5 and decreased the cell proliferation rate. In multiple intestinal neoplasia (Min) mice, daily administration of monensin suppressed progression of the intestinal tumors without any sign of toxicity on normal mucosa. Our data suggest monensin as a prospective anticancer drug for therapy of neoplasia with deregulated Wnt signaling.
- MeSH
- antibiotika antitumorózní farmakologie terapeutické užití MeSH
- beta-katenin metabolismus MeSH
- dánio pruhované MeSH
- experimentální nádory MeSH
- HEK293 buňky MeSH
- kolorektální nádory farmakoterapie patologie MeSH
- LDL receptor related protein 6 metabolismus MeSH
- lidé MeSH
- monensin farmakologie terapeutické užití MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- proliferace buněk účinky léků MeSH
- regulace genové exprese u nádorů účinky léků MeSH
- signální dráha Wnt účinky léků MeSH
- xenogenní modely - testy antitumorózní aktivity MeSH
- Xenopus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND & AIMS: The Wnt signaling pathway is required for maintenance of the intestinal epithelia; blocking this pathway reduces the proliferative capacity of the intestinal stem cells. However, aberrant Wnt signaling leads to intestinal cancer. We investigated the roles of the Wnt pathway in homeostasis of the intestinal epithelium and during malignant transformation in human cells and mice. METHODS: We performed chromatin immunoprecipitation (ChIP) with DNA microarray analysis (ChIP-on-chip) to identify genes regulated by Wnt signaling in human colorectal cancer cells Colo320, DLD1, LS174T, and SW480. Formation of intestinal tumor was induced in C57BL/6J mice using azoxymethane and dextran sulfate. Intestinal tissues from these mice, as well as Apc(+/Min) and Apc(CKO/CKO)/Lgr5-EGFP-IRES-CreERT2 mice, were analyzed by immunohistochemistry and in situ hybridization. RESULTS: We identified promoter regions of 960 genes that interacted with the Wnt pathway nuclear effector T-cell factor 4 in 4 different human colorectal cancer-derived cell lines; 18 of these promoters were present in all chromatin precipitates. Wnt signaling up-regulated a member of the tumor necrosis factor receptor superfamily called TROY. Levels of TROY messenger RNA were increased in human cells with deficiencies in the adenomatous polyposis coli (APC) gene and in cells stimulated with the Wnt3a ligand. Expression of Troy was significantly up-regulated in neoplastic tissues from mice during intestinal tumorigenesis. Lineage tracing experiments revealed that Troy is produced specifically by fast-cycling intestinal stem cells. TROY associated with a unique marker of these cells, leucine-rich repeat-containing G-protein coupled receptor (LGR) 5. In organoids established from the intestinal crypts, Troy suppressed signaling mediated by R-spondin, a Wnt agonist. CONCLUSIONS: TROY is up-regulated in human colorectal cancer cell lines and in intestinal tumors in mice. It functions as a negative modulator of the Wnt pathway in LGR5-positive stem cells.
- MeSH
- apoptóza MeSH
- experimentální nádory MeSH
- hybridizace in situ MeSH
- imunohistochemie MeSH
- kolorektální nádory genetika metabolismus patologie MeSH
- lidé MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- nádorová transformace buněk genetika metabolismus patologie MeSH
- nádorové buněčné linie MeSH
- nádorové kmenové buňky metabolismus patologie MeSH
- polymerázová řetězová reakce s reverzní transkripcí MeSH
- proliferace buněk MeSH
- receptory spřažené s G-proteiny fyziologie MeSH
- receptory TNF fyziologie MeSH
- regulace genové exprese u nádorů * MeSH
- RNA nádorová genetika MeSH
- sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
- signální dráha Wnt fyziologie MeSH
- střevní sliznice metabolismus patologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
