Search results for "Notch Signaling"

2017

Strategies for promoting neural regeneration are hindered by the difficulty of manipulating desired neural fates in the brain without complex genetic methods. The subventricular zone (SVZ) is the largest germinal zone of the forebrain and is responsible for the lifelong generation of interneuron subtypes and oligodendrocytes. Here, we have performed a bioinformatics analysis of the transcriptome of dorsal and lateral SVZ in early postnatal mice, including neural stem cells (NSCs) and their immediate progenies, which generate distinct neural lineages. We identified multiple signaling pathways that trigger distinct downstream transcriptional networks to regulate the diversity of neural cells …

Programming of Intestinal Epithelial Differentiation by IL-33 Derived from Pericryptal Fibroblasts in Response to Systemic Infection.

2016

SummaryThe intestinal epithelium constitutes an efficient barrier against the microbial flora. Here, we demonstrate an unexpected function of IL-33 as a regulator of epithelial barrier functions. Mice lacking IL-33 showed decreased Paneth cell numbers and lethal systemic infection in response to Salmonella typhimurium. IL-33 was produced upon microbial challenge by a distinct population of pericryptal fibroblasts neighboring the intestinal stem cell niche. IL-33 programmed the differentiation of epithelial progenitors toward secretory IEC including Paneth and goblet cells. Finally, IL-33 suppressed Notch signaling in epithelial cells and induced expression of transcription factors governing…

Active Akt signaling triggers CLL toward Richter transformation via overactivation of Notch1

2021

Abstract Richter’s transformation (RT) is an aggressive lymphoma that occurs upon progression from chronic lymphocytic leukemia (CLL). Transformation has been associated with genetic aberrations in the CLL phase involving TP53, CDKN2A, MYC, and NOTCH1; however, a significant proportion of RT cases lack CLL phase–associated events. Here, we report that high levels of AKT phosphorylation occur both in high-risk CLL patients harboring TP53 and NOTCH1 mutations as well as in patients with RT. Genetic overactivation of Akt in the murine Eµ-TCL1 CLL mouse model resulted in CLL transformation to RT with significantly reduced survival and an aggressive lymphoma phenotype. In the absence of recurren…

Telomere Shortening in Neural Stem Cells Disrupts Neuronal Differentiation and Neuritogenesis

2009

Proliferation in the subependymal zone (SEZ) and neurogenesis in the olfactory bulb decline in the forebrain of telomerase-deficient mice. The present work reveals additional effects of telomere shortening on neuronal differentiation, as adult multipotent progenitors with critically short telomeres yield reduced numbers of neurons that, furthermore, exhibit underdeveloped neuritic arbors. Genetic data indicate that the tumor suppressor protein p53 not only mediates the adverse effects of telomere attrition on proliferation and self-renewal but it is also involved in preventing normal neuronal differentiation of adult progenitors with dysfunctional telomeres. Interestingly, progenitor cells …

Notch inhibition restores TRAIL-mediated apoptosis via AP1-dependent upregulation of DR4 and DR5 TRAIL receptors in MDA-MB-231 breast cancer cells.

2013

Notch is a family of transmembrane receptors whose activation through proteolytic cleavage by γ-secretase targets genes which participate in cell development, differentiation and tumorigenesis. Notch signaling is constitutively activated in various cancers, including breast cancer and its upregulation is usually related with poor clinical outcomes. Therefore, targeting Notch signaling with γ-secretase inhibitors (GSIs) is considered a promising strategy for cancer treatment. We report that the γ-secretase inhibitor-I (GSI-I) sensitizes human breast cancer cells to apoptosis mediated by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). The antiproliferative GSI-I/TRAIL synergi…

Abstract PR10: Inhibition of deacetylase SIRT1 offers a novel treatment option in metastatic Ewing sarcoma

2014

Abstract Metastasis is the major cause of disease-related death in Ewing sarcoma. Patients, who present with clinically overt disseminated disease at diagnosis and those who relapse early with distant metastases have a poor outcome despite multi-modal high-dose chemotherapy. Therefore, new treatment options are highly warranted. Ewing sarcoma pathogenesis is driven by the chimeric ETS oncogene EWS-FLI1. We here describe regulation of sirtuin SIRT1 by EWS-FLI1 and its role in metastasis. SIRT1 belongs to a family of NAD+-dependent group III deacetylases that target histone and non-histone proteins in response to metabolic stress resulting in widespread gene expression changes through epigene…

2015

Notch receptors play an essential role in the regulation of central cellular processes during embryonic and postnatal development. The mammalian genome encodes for four Notch paralogs (Notch 1-4), which are activated by three Delta-like (Dll1/3/4) and two Serrate-like (Jagged1/2) ligands. Further, non-canonical Notch ligands such as EGFL7 have been identified and serve mostly as antagonists of Notch signaling. The Notch pathway prevents neuronal differentiation in the central nervous system by driving neural stem cell maintenance and commitment of neural progenitor cells into the glial lineage. Notch is therefore often implicated in the development of brain tumors, as tumor cells share vari…

Abstract 1918: Gene characterization of lung-tumorspheres for their usage as an in vitro screening platform for testing new therapeutic strategies

2017

Abstract Background: Lung cancer features like treatment resistance or tumor relapse have been linked to cancer stem cells (CSCs), a population of cells with self-renewal properties, and the ability to grow forming tumorspheres in non-adherent conditions. The aim of this study was to isolate and characterize tumorspheres from lung cancer cell lines and tumor tissue from resectable non-small cell lung cancer (NSCLC) patients and to use them as an in vitro platform for drug screening. Methods: This study was performed on cells from seven NSCLC tumor samples and five cell lines (H1650, H1993, H1395, A549 and PC9) grown in monolayer and as spheroids. The expression of 60 genes, including CSC-ma…

Vascular niche factor PEDF modulates Notch-dependent stemness in the adult subependymal zone.

2009

We sought to address the fundamental question of how stem cell microenvironments can regulate self-renewal. We found that Notch was active in astroglia-like neural stem cells (NSCs), but not in transit-amplifying progenitors of the murine subependymal zone, and that the level of Notch transcriptional activity correlated with self-renewal and multipotency. Moreover, dividing NSCs appeared to balance renewal with commitment via controlled segregation of Notch activity, leading to biased expression of known (Hes1) and previously unknown (Egfr) Notch target genes in daughter cells. Pigment epithelium-derived factor (PEDF) enhanced Notch-dependent transcription in cells with low Notch signaling,…

The complex interplay between Notch signaling and Snail1 transcription factor in the regulation of epithelial–mesenchymal transition (EMT)

2015

Background The epithelial–mesenchymal transition (EMT) is a highly coordinated process observed during embryonic development and adult tissue repair. It is characterized by the loss of cell–cell adhesion and apicobasal polarity, and the transition to a cell type with a spindle-like phenotype able to migrate through the basal membranes. Methods This review article includes available date from peer-reviewed publications associated with the role of Notch signaling and Snail1 transcription factor in activation and regulation of EMT. Results Growing evidences in the past few years demonstrated a significant role of Notch in EMT activation. It is not surprising because this pathway is the nexus o…