scholarly journals Top Notch Targeting Strategies in Cancer: A Detailed Overview of Recent Insights and Current Perspectives

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1503 ◽  
Author(s):  
Gillian Moore ◽  
Stephanie Annett ◽  
Lana McClements ◽  
Tracy Robson
Keyword(s):  
Critical Role ◽  
Acquired Resistance ◽  
Tumour Microenvironment ◽  
Phase Iii ◽  
Cell Renewal ◽  
Gamma Secretase ◽  
Cancer Hallmarks ◽  
Activating Mutations ◽  
Stem Cell Renewal ◽  
Exciting Time

Evolutionarily conserved Notch plays a critical role in embryonic development and cellular self-renewal. It has both tumour suppressor and oncogenic activity, the latter of which is widely described. Notch-activating mutations are associated with haematological malignancies and several solid tumours including breast, lung and adenoid cystic carcinoma. Moreover, upregulation of Notch receptors and ligands and aberrant Notch signalling is frequently observed in cancer. It is involved in cancer hallmarks including proliferation, survival, migration, angiogenesis, cancer stem cell renewal, metastasis and drug resistance. It is a key component of cell-to-cell interactions between cancer cells and cells of the tumour microenvironment, such as endothelial cells, immune cells and fibroblasts. Notch displays diverse crosstalk with many other oncogenic signalling pathways, and may drive acquired resistance to targeted therapies as well as resistance to standard chemo/radiation therapy. The past 10 years have seen the emergence of different classes of drugs therapeutically targeting Notch including receptor/ligand antibodies, gamma secretase inhibitors (GSI) and most recently, the development of Notch transcription complex inhibitors. It is an exciting time for Notch research with over 70 cancer clinical trials registered and the first-ever Phase III trial of a Notch GSI, nirogacestat, currently at the recruitment stage.

scholarly journals An amphipathic motif at the transmembrane-cytoplasmic junction prevents autonomous activation of the thrombopoietin receptor

Blood ◽  
2006 ◽  
Vol 107 (5) ◽  
pp. 1864-1871 ◽  
Author(s):  
Judith Staerk ◽  
Catherine Lacout ◽  
Takeshi Sato ◽  
Steven O. Smith ◽  
William Vainchenker ◽  
...  
Keyword(s):  
Erythroid Differentiation ◽  
Erythropoietin Receptor ◽  
Cell Renewal ◽  
Hematopoietic Stem ◽  
Activating Mutations ◽  
Stem Cell Renewal ◽  
Thrombopoietin Receptor ◽  
Stat3 Phosphorylation ◽  
Protein Map ◽  
Mitogen Activated Protein

Ligand binding to the thrombopoietin receptor (TpoR) is thought to impose a dimeric receptor conformation(s) leading to hematopoietic stem cell renewal, megakaryocyte differentiation, and platelet formation. Unlike other cytokine receptors, such as the erythropoietin receptor, TpoR contains an amphipathic KWQFP motif at the junction between the transmembrane (TM) and cytoplasmic domains. We show here that a mutant TpoR (Δ5TpoR), where this sequence was deleted, is constitutively active. In the absence of ligand, Δ5TpoR activates Jak2, Tyk2, STAT5, and mitogen-activated protein (MAP) kinase, but does not appear to induce STAT3 phosphorylation. Δ5TpoR induces hematopoietic myeloid differentiation in the absence of Tpo. In the presence of Tpo, the Δ5TpoR mutant appears to enhance erythroid differentiation when compared with the Tpo-activated wild-type TpoR. Strikingly, individual substitution of K507 or W508 to alanine also induces constitutive TpoR activation, indicating that the K and W residues within the amphipathic KWQFP motif are crucial for maintaining the unliganded receptor inactive. These residues may be targets for activating mutations in humans. Such a motif may exist in other receptors to prevent ligand-independent activation and to allow signaling via multiple flexible interfaces.

scholarly journals Interplay between RNA Viruses and Promyelocytic Leukemia Nuclear Bodies

2021 ◽  
Vol 8 (4) ◽  
pp. 57
Author(s):  
Sabari Nath Neerukonda
Keyword(s):  
Rna Viruses ◽  
Critical Role ◽  
Promyelocytic Leukemia ◽  
Nuclear Bodies ◽  
Cell Renewal ◽  
Immune Functions ◽  
Stem Cell Renewal ◽  
Cellular Environment ◽  
Core Proteins ◽  
Promyelocytic Leukemia Nuclear Bodies

Promyelocytic leukemia nuclear bodies (PML NBs) are nuclear membrane-less sub structures that play a critical role in diverse cellular pathways including cell proliferation, DNA damage, apoptosis, transcriptional regulation, stem cell renewal, alternative lengthening of telomeres, chromatin organization, epigenetic regulation, protein turnover, autophagy, intrinsic and innate antiviral immunity. While intrinsic and innate immune functions of PML NBs or PML NB core proteins are well defined in the context of nuclear replicating DNA viruses, several studies also confirm their substantial roles in the context of RNA viruses. In the present review, antiviral activities of PML NBs or its core proteins on diverse RNA viruses that replicate in cytoplasm or the nucleus were discussed. In addition, viral counter mechanisms that reorganize PML NBs, and specifically how viruses usurp PML NB functions in order to create a cellular environment favorable for replication and pathogenesis, are also discussed.

scholarly journals A critical role for Musashi in photoreceptor morphogenesis and Vision

2020 ◽  
Author(s):  
Jesse Sundar ◽  
Fatimah Matalkah ◽  
Bohye Jeong ◽  
Peter Stoilov ◽  
Visvanathan Ramamurthy
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Neuronal Degeneration ◽  
Critical Role ◽  
Conditional Knockout ◽  
Cell Renewal ◽  
Rod Photoreceptor ◽  
Stem Cell Renewal ◽  
Conditional Knockout Mouse ◽  
Photoreceptor Neurons

ABSTRACTMusashi family of RNA-binding proteins are known for their role in stem-cell renewal and are negative regulators of cell differentiation. Interestingly, in the retina, Musashi proteins, MSI1 and MSI2 are differentially expressed throughout the cycle of retinal development including robust expression in the adult retinal tissue. To study the role of Musashi proteins in the retina, we generated a pan-retinal and rod photoreceptor neuron specific conditional knockout mouse lacking MSI1 and MSI2. Independent of sex, photoreceptor neurons with simultaneous deletion of Msi1 and Msi2 were unable to respond to light and displayed severely disrupted OS morphology and ciliary defects. The retina lacking Musashi exhibited neuronal degeneration with complete loss of photoreceptors by six months. In concordance with our earlier studies that proposed a role for Musashi in regulating alternative splicing, the loss of Musashi prevented the use of photoreceptor-specific exons in transcripts critical for OS morphogenesis, ciliogenesis and synaptic transmission. Overall, we demonstrate a critical role for Musashi in the morphogenesis of terminally differentiated photoreceptor neurons. This role is in stark contrast with the canonical function of these two proteins in maintenance and renewal of stem cells.

scholarly journals miR-200c and GATA binding protein 4 regulate human embryonic stem cell renewal and differentiation

2014 ◽  
Vol 12 (2) ◽  
pp. 338-353 ◽  
Author(s):  
Hsiao-Ning Huang ◽  
Shao-Yin Chen ◽  
Shiaw-Min Hwang ◽  
Ching-Chia Yu ◽  
Ming-Wei Su ◽  
...  
Keyword(s):  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Human Embryonic Stem Cell ◽  
Binding Protein ◽  
Embryonic Stem ◽  
Cell Renewal ◽  
Stem Cell Renewal

scholarly journals Protein misfolding, amyotrophic lateral sclerosis and guanabenz: protocol for a phase II RCT with futility design (ProMISe trial)

BMJ Open ◽  
2017 ◽  
Vol 7 (8) ◽  
pp. e015434 ◽  
Author(s):  
Eleonora Dalla Bella ◽  
Irene Tramacere ◽  
Giovanni Antonini ◽  
Giuseppe Borghero ◽  
Margherita Capasso ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Amyotrophic Lateral Sclerosis ◽  
Placebo Group ◽  
Phase Ii ◽  
Critical Role ◽  
Protein Translation ◽  
Phase Iii ◽  
Protein Accumulation ◽  
Neuroprotective Effects ◽  
Lateral Sclerosis

IntroductionRecent studies suggest that endoplasmic reticulum stress may play a critical role in the pathogenesis of amyotrophic lateral sclerosis (ALS) through an altered regulation of the proteostasis, the cellular pathway-balancing protein synthesis and degradation. A key mechanism is thought to be the dephosphorylation of eIF2α, a factor involved in the initiation of protein translation. Guanabenz is an alpha-2-adrenergic receptor agonist safely used in past to treat mild hypertension and is now an orphan drug. A pharmacological action recently discovered is its ability to modulate the synthesis of proteins by the activation of translational factors preventing misfolded protein accumulation and endoplasmic reticulum overload. Guanabenz proved to rescue motoneurons from misfolding protein stress both in in vitro and in vivo ALS models, making it a potential disease-modifying drug in patients. It is conceivable investigating whether its neuroprotective effects based on the inhibition of eIF2α dephosphorylation can change the progression of ALS.Methods and analysesProtocolised Management In Sepsis is a multicentre, randomised, double-blind, placebo-controlled phase II clinical trial with futility design. We will investigate clinical outcomes, safety, tolerability and biomarkers of neurodegeneration in patients with ALS treated with guanabenz or riluzole alone for 6 months. The primary aim is to test if guanabenz can reduce the proportion of patients progressed to a higher stage of disease at 6 months compared with their baseline stage as measured by the ALS Milano-Torino Staging (ALS-MITOS) system and to the placebo group. Secondary aims are safety, tolerability and change in at least one biomarker of neurodegeneration in the guanabenz arm compared with the placebo group. Findings will provide reliable data on the likelihood that guanabenz can slow the course of ALS in a phase III trial.Ethics and disseminationThe study protocol was approved by the Ethics Committee of IRCCS ‘Carlo Besta Foundation’ of Milan (Eudract no. 2014-005367-32 Pre-results) based on the Helsinki declaration.

scholarly journals The decapentaplegic core promoter region plays an integral role in the spatial control of transcription.

1995 ◽  
Vol 15 (7) ◽  
pp. 3960-3968 ◽  
Author(s):  
D H Schwyter ◽  
J D Huang ◽  
T Dubnicoff ◽  
A J Courey
Keyword(s):  
Expression Pattern ◽  
Phase Ii ◽  
Promoter Region ◽  
Core Promoter ◽  
Critical Role ◽  
Regulatory Elements ◽  
Drosophila Embryo ◽  
Phase Iii ◽  
Core Promoter Region ◽  
Flanking Region

The Drosophila melanogaster decapentaplegic (dpp) gene encodes a transforming growth factor beta-related cell signaling molecule that plays a critical role in dorsal/ventral pattern formation. The dpp expression pattern in the Drosophila embryo is dynamic, consisting of three phases. Phase I, in which dpp is expressed in a broad dorsal domain, depends on elements in the dpp second intron that interact with the Dorsal transcription factor to repress transcription ventrally. In contrast, phases II and III, in which dpp is expressed first in broad longitudinal stripes (phase II) and subsequently in narrow longitudinal stripes (phase III), depend on multiple independent elements in the dpp 5'-flanking region. Several aspects of the normal dpp expression pattern appear to depend on the unique properties of the dpp core promoter. For example, this core promoter (extending from -22 to +6) is able to direct a phase II expression pattern in the absence of additional upstream or downstream regulatory elements. In addition, a ventral-specific enhancer in the dpp 5'-flanking region that binds the Dorsal factor activates the heterologous hsp70 core promoter but not the dpp core promoter. Thus, the dpp core promoter region may contribute to spatially regulated transcription both by interacting directly with spatially restricted activators and by modifying the activity of proteins bound to enhancer elements.

scholarly journals Activating mutations in BRAF disrupt the hypothalamo-pituitary axis leading to hypopituitarism in mice and humans

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Angelica Gualtieri ◽  
Nikolina Kyprianou ◽  
Louise C. Gregory ◽  
Maria Lillina Vignola ◽  
James G. Nicholson ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Critical Role ◽  
Cell Lineage ◽  
Activating Mutations ◽  
Pathway Activation ◽  
Tumour Formation ◽  
Conditional Expression ◽  
Cell Cycle Inhibitors ◽  
Mutation Braf

AbstractGermline mutations in BRAF and other components of the MAPK pathway are associated with the congenital syndromes collectively known as RASopathies. Here, we report the association of Septo-Optic Dysplasia (SOD) including hypopituitarism and Cardio-Facio-Cutaneous (CFC) syndrome in patients harbouring mutations in BRAF. Phosphoproteomic analyses demonstrate that these genetic variants are gain-of-function mutations leading to activation of the MAPK pathway. Activation of the MAPK pathway by conditional expression of the BrafV600E/+ allele, or the knock-in BrafQ241R/+ allele (corresponding to the most frequent human CFC-causing mutation, BRAF p.Q257R), leads to abnormal cell lineage determination and terminal differentiation of hormone-producing cells, causing hypopituitarism. Expression of the BrafV600E/+ allele in embryonic pituitary progenitors leads to an increased expression of cell cycle inhibitors, cell growth arrest and apoptosis, but not tumour formation. Our findings show a critical role of BRAF in hypothalamo-pituitary-axis development both in mouse and human and implicate mutations found in RASopathies as a cause of endocrine deficiencies in humans.

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