Cardiac induction of embryonic stem cells by a small molecule inhibitor of Wnt/?-catenin signaling.
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ABSTRACT:
SUBMITTER: Wang H
PROVIDER: S-EPMC3076310 | biostudies-literature | 2011 Feb
REPOSITORIES: biostudies-literature
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Project description:Wnt/?-catenin signaling is a branch of a functional network that dates back to the first metazoans and it is involved in a broad range of biological systems including stem cells, embryonic development and adult organs. Deregulation of components involved in Wnt/?-catenin signaling has been implicated in a wide spectrum of diseases including a number of cancers and degenerative diseases. The key mediator of Wnt signaling, ?-catenin, serves several cellular functions. It functions in a dynamic mode at multiple cellular locations, including the plasma membrane, where ?-catenin contributes to the stabilization of intercellular adhesive complexes, the cytoplasm where ?-catenin levels are regulated and the nucleus where ?-catenin is involved in transcriptional regulation and chromatin interactions. Central effectors of ?-catenin levels are a family of cysteine-rich secreted glycoproteins, known as Wnt morphogens. Through the LRP5/6-Frizzled receptor complex, Wnts regulate the location and activity of the destruction complex and consequently intracellular ?- catenin levels. However, ?-catenin levels and their effects on transcriptional programs are also influenced by multiple other factors including hypoxia, inflammation, hepatocyte growth factor-mediated signaling, and the cell adhesion molecule E-cadherin. The broad implications of Wnt/?-catenin signaling in development, in the adult body and in disease render the pathway a prime target for pharmacological research and development. The intricate regulation of ?-catenin at its various locations provides alternative points for therapeutic interventions.
| S-EPMC3529405 | biostudies-literature
Project description:The Wnt signal transduction pathway is dysregulated in many highly prevalent diseases, including cancer. Unfortunately, drug discovery efforts have been hampered by the paucity of targets and drug-like lead molecules amenable to drug discovery. Recently, we reported the FDA-approved anthelmintic drug Niclosamide inhibits Wnt/β-catenin signaling by a unique mechanism, though the target responsible remains unknown. We interrogated the mechanism and structure-activity relationships to understand drivers of potency and to assist target identification efforts. We found inhibition of Wnt signaling by Niclosamide appears unique among the structurally-related anthelmintic agents tested and found the potency and functional response was dependent on small changes in the chemical structure of Niclosamide. Overall, these findings support efforts to identify the target of Niclosamide inhibition of Wnt/β-catenin signaling and the discovery of potent and selective modulators to treat human disease.
| S-EPMC3660039 | biostudies-literature
Project description:Wnt/beta-catenin signaling is an important regulator of differentiation and morphogenesis that can also control stem cell fates. Our group has developed an efficient protocol to generate cardiomyocytes from human embryonic stem (ES) cells via induction with activin A and BMP4.We tested the hypothesis that Wnt/beta-catenin signals control both early mesoderm induction and later cardiac differentiation in this system. Addition of exogenous Wnt3a at the time of induction enhanced cardiac differentiation, while early inhibition of endogenous Wnt/beta-catenin signaling with Dkk1 inhibited cardiac differentiation, as indicated by quantitative RT-PCR analysis for beta-myosin heavy chain (beta-MHC), cardiac troponin T (cTnT), Nkx2.5, and flow cytometry analysis for sarcomeric myosin heavy chain (sMHC). Conversely, late antagonism of endogenously produced Wnts enhanced cardiogenesis, indicating a biphasic role for the pathway in human cardiac differentiation. Using quantitative RT-PCR, we show that canonical Wnt ligand expression is induced by activin A/BMP4 treatment, and the extent of early Wnt ligand expression can predict the subsequent efficiency of cardiogenesis. Measurement of Brachyury expression showed that addition of Wnt3a enhances mesoderm induction, whereas blockade of endogenously produced Wnts markedly inhibits mesoderm formation. Finally, we show that Wnt/beta-catenin signaling is required for Smad1 activation by BMP4.Our data indicate that induction of mesoderm and subsequent cardiac differentiation from human ES cells requires fine-tuned cross talk between activin A/BMP4 and Wnt/beta-catenin pathways. Controlling these pathways permits efficient generation of cardiomyocytes for basic studies or cardiac repair applications.
| S-EPMC2886114 | biostudies-literature
Project description:Understanding pathways controlling cardiac development may offer insights that are useful for stem cell-based cardiac repair. Developmental studies indicate that the Wnt/beta-catenin pathway negatively regulates cardiac differentiation, whereas studies with pluripotent embryonal carcinoma cells suggest that this pathway promotes cardiogenesis. This apparent contradiction led us to hypothesize that Wnt/beta-catenin signaling acts biphasically, either promoting or inhibiting cardiogenesis depending on timing. We used inducible promoters to activate or repress Wnt/beta-catenin signaling in zebrafish embryos at different times of development. We found that Wnt/beta-catenin signaling before gastrulation promotes cardiac differentiation, whereas signaling during gastrulation inhibits heart formation. Early treatment of differentiating mouse embryonic stem (ES) cells with Wnt-3A stimulates mesoderm induction, activates a feedback loop that subsequently represses the Wnt pathway, and increases cardiac differentiation. Conversely, late activation of beta-catenin signaling reduces cardiac differentiation in ES cells. Finally, constitutive overexpression of the beta-catenin-independent ligand Wnt-11 increases cardiogenesis in differentiating mouse ES cells. Thus, Wnt/beta-catenin signaling promotes cardiac differentiation at early developmental stages and inhibits it later. Control of this pathway may promote derivation of cardiomyocytes for basic research and cell therapy applications.
| S-EPMC1876428 | biostudies-literature
Project description:The Wnt/beta-catenin signaling pathway regulates cell fate and behavior during embryogenesis, adult tissue homeostasis, and regeneration. When inappropriately activated, the pathway has been linked to colorectal cancer and melanoma, and when attenuated it may contribute to Alzheimer's disease and osteoporosis. Small molecules that modulate Wnt signaling will likely provide new insights into the regulation of this key developmental pathway and ultimately provide pharmacological agents to control Wnt signaling in vivo. To this end, we screened a library of 100,000 small molecules for activity in a cell-based assay of Wnt/beta-catenin signaling and discovered a purine derivative, QS11, that synergizes with Wnt-3a ligand in the activation of Wnt/beta-catenin signal transduction. Through affinity chromatography and subsequent functional assays, we showed that QS11 binds and inhibits the GTPase activating protein of ADP-ribosylation factor 1 (ARFGAP1), suggesting that QS11 modulates Wnt/beta-catenin signaling through an effect on protein trafficking. Consistent with its function as an ARFGAP inhibitor, QS11 inhibits migration of ARFGAP overexpressing breast cancer cells.
| S-EPMC1863490 | biostudies-literature
Project description:Although several epigenetic modulating drugs are suggested to target cancer stem cells (CSCs), additional identification of anti-CSC drugs is still necessary. Here we showed that JIB-04, a pan-selective inhibitor of histone demethylase(s), was identified as a small molecule that selectively target colorectal CSCs. Our data showed that JIB-04 is capable of reducing self-renewal and stemness of colorectal CSCs in three different colorectal cancer cell lines. JIB-04 significantly attenuated CSC tumorsphere formation, growth/relapse, invasion, and migration in vitro. Furthermore, JIB-04-treated colorectal cancer cells showed reduced tumorigenic activity in vivo. RNA sequencing analysis revealed that JIB-04 affected various cancer-related signaling pathways, especially Wnt/β-catenin signaling, which is crucial for the proliferation and maintenance of colorectal cancer cells. qRT-PCR and TOP/FOP flash luciferase assays showed that JIB-04 down-regulated the expression of Wnt/β-catenin-regulated target genes associated with colorectal CSC function. Overall, the effects of JIB-04 were equal to or greater than those of salinomycin, a known anti-colorectal CSC drug, despite the lower concentration of JIB-04 compared with that of salinomycin. Our results strongly suggest that JIB-04 is a promising drug candidate for colorectal cancer therapy.
| S-EPMC5919936 | biostudies-literature
Project description:BackgroundEmbryonic stem cells (ESCs) are pluripotent stem cells and can form tumors containing cells from all three germ layers. Similarities between pluripotent stem cells and malignant tumor cells have been identified. The purpose of this study was to obtain ESCs-converted tumor cell lines and to investigate the mechanism of malignancy in pluripotent stem cells.MethodsMouse ESCs were subcutaneously injected into nude mice to obtain tumors from which a tumor-like cell line (ECCs1) was established by culturing the cells in chemical-defined N2B27 medium supplied with two small molecular inhibitors CHIR99021 and PD0325901 (2i). The ECCs1 were then subcutaneously injected into nude mice again to obtain tumors from which another tumor-like cells line (ECCs2) was established in the same 2i medium. The malignant degree of ESCs, ECCs1 and ECCs2 was compared and the underlying mechanism involved in the malignancy development of ESCs was examined.ResultsThe three ESCs, ECCs1 and ECCs2 cell lines were cultured in the same 2i condition and showed some likeness such as Oct4-expression and long-term expansion ability. However, the morphology and the tumor-formation ability of the cell lines were different. We identified that ECCs1 and ECCs2 gradually acquired malignancy. Moreover, Wnt signaling-related genes such as CD133 and ?-catenin expression were up-regulated and Frizzled related protein (FRP) was down-regulated during the tumor development of ESCs.ConclusionsThe two tumor-like cell lines ECCs1 and ECCs2 stand for early malignant development stage of ESCs and the ECCs2 was more malignant than the ECCs1. Moreover, we identified that Wnt/?-catenin signaling played an important role in the malignancy process of ESCs.
| S-EPMC3515512 | biostudies-literature
Project description:Pluripotent embryonic stem (ES) cells, which have the capacity to give rise to all tissue types in the body, show great promise as a versatile source of cells for regenerative therapy. However, the basic mechanisms of lineage specification of pluripotent stem cells are largely unknown, and generating sufficient quantities of desired cell types remains a formidable challenge. Small molecules, particularly those that modulate key developmental pathways like the bone morphogenetic protein (BMP) signaling cascade, hold promise as tools to study in vitro lineage specification and to direct differentiation of stem cells toward particular cell types.We describe the use of dorsomorphin, a selective small molecule inhibitor of BMP signaling, to induce myocardial differentiation in mouse ES cells. Cardiac induction is very robust, increasing the yield of spontaneously beating cardiomyocytes by at least 20 fold. Dorsomorphin, unlike the endogenous BMP antagonist Noggin, robustly induces cardiomyogenesis when treatment is limited to the initial 24-hours of ES cell differentiation. Quantitative-PCR analyses of differentiating ES cells indicate that pharmacological inhibition of BMP signaling during the early critical stage promotes the development of the cardiomyocyte lineage, but reduces the differentiation of endothelial, smooth muscle, and hematopoietic cells.Administration of a selective small molecule BMP inhibitor during the initial stages of ES cell differentiation substantially promotes the differentiation of primitive pluripotent cells toward the cardiomyocytic lineage, apparently at the expense of other mesodermal lineages. Small molecule modulators of developmental pathways like dorsomorphin could become versatile pharmacological tools for stem cell research and regenerative medicine.
| S-EPMC2483414 | biostudies-other
Project description:Embryonic stem cells (ESCs) represent an important research tool and a potential resource for regenerative medicine. Generally, ESCs are cocultured with a supportive feeder cell layer of murine embryonic fibroblasts, which maintain the ESCs' capacity for self-renewal and block spontaneous differentiation. These cumbersome conditions, as well as the risk of xenobiotic contamination of human ESCs grown on murine embryonic fibroblasts, make it a priority to develop chemically defined methods that can be safely used for the expansion of ESCs. Using a high-throughput, cell-based assay, we identified the small molecule IQ-1 that allows for the Wnt/beta-catenin-driven long-term expansion of mouse ESCs and prevents spontaneous differentiation. We demonstrate that IQ-1, by targeting the PR72/130 subunit of the serine/threonine phosphatase PP2A, prevents beta-catenin from switching coactivator usage from CBP to p300. The increase in beta-catenin/CBP-mediated transcription at the expense of beta-catenin/p300-mediated transcription is critical for the maintenance of murine stem cell pluripotency.
| S-EPMC1838514 | biostudies-literature
Project description:The Wnt/?-catenin signaling pathway plays a major role in tissue homeostasis, and its dysregulation can lead to various human diseases. Aberrant activation of ?-catenin is oncogenic and is a critical driver in the development and progression of human cancers. Despite the significant potential of targeting the oncogenic ?-catenin pathway for cancer therapy, the development of specific inhibitors remains insufficient. Using a T cell factor (TCF)-dependent luciferase-reporter system, we screened for small-molecule compounds that act against Wnt/?-catenin signaling and identified MSAB (methyl 3-{[(4-methylphenyl)sulfonyl]amino}benzoate) as a selective inhibitor of Wnt/?-catenin signaling. MSAB shows potent anti-tumor effects selectively on Wnt-dependent cancer cells in vitro and in mouse cancer models. MSAB binds to ?-catenin, promoting its degradation, and specifically downregulates Wnt/?-catenin target genes. Our findings might represent an effective therapeutic strategy for cancers addicted to the Wnt/?-catenin signaling pathway.
| S-EPMC4957947 | biostudies-literature