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Bodhale N, Nair A, Saha B. Isoform-specific functions of Ras in T-cell development and differentiation. Eur J Immunol 2023; 53:e2350430. [PMID: 37173132 DOI: 10.1002/eji.202350430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/02/2023] [Accepted: 05/11/2023] [Indexed: 05/15/2023]
Abstract
Ras GTPases, well characterized for their role in oncogenesis, are the cells' molecular switches that signal to maintain immune homeostasis through cellular development, proliferation, differentiation, survival, and apoptosis. In the immune system, T cells are the central players that cause autoimmunity if dysregulated. Antigen-specific T-cell receptor (TCR) stimulation activates Ras-isoforms, which exhibit isoform-specific activator and effector requirements, functional specificities, and a selective role in T-cell development and differentiation. Recent studies show the role of Ras in T-cell-mediated autoimmune diseases; however, there is a scarcity of knowledge about the role of Ras in T-cell development and differentiation. To date, limited studies have demonstrated Ras activation in response to positive and negative selection signals and Ras isoform-specific signaling, including subcellular signaling, in immune cells. The knowledge of isoform-specific functions of Ras in T cells is essential, but still inadequate to develop the T-cell-targeted Ras isoform-specific treatment strategies for the diseases caused by altered Ras-isoform expression and activation in T cells. In this review, we discuss the role of Ras in T-cell development and differentiation, critically analyzing the isoform-specific functions.
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Affiliation(s)
| | - Arathi Nair
- National Centre for Cell Science, Pune, India
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2
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Minati MA, Assi M, Libert M, Cordi S, Lemaigre F, Jacquemin P. KRAS protein expression becomes progressively restricted during embryogenesis and in adulthood. Front Cell Dev Biol 2022; 10:995013. [PMID: 36238685 PMCID: PMC9551567 DOI: 10.3389/fcell.2022.995013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 08/29/2022] [Indexed: 11/24/2022] Open
Abstract
KRAS mutants are common in many cancers and wild-type KRAS is essential in development as its absence causes embryonic lethality. Despite this critical role in development and disease, the normal expression pattern of KRAS protein is still largely unknown at the tissue level due to the lack of valid antibodies. To address this issue, we used the citrine-Kras mouse model in which the Citrine-KRAS (Cit-K) fusion protein functions as a validated surrogate of endogenous KRAS protein that can be detected on tissue sections by immunolabeling with a GFP antibody. In the embryo, we found expression of KRAS protein in a wide range of organs and tissues. This expression tends to decrease near birth, mainly in mesenchymal cells. During transition to the adult stage, the dynamics of KRAS protein expression vary among organs and detection of KRAS becomes restricted to specific cell types. Furthermore, we found that steady state KRAS protein expression is detectable at the cell membrane and in the cytoplasm and that this subcellular partitioning differed among cell types. Our results reveal hitherto unanticipated dynamics in developmental, tissular, cell-specific and subcellular expression of KRAS protein. They provide insight into the reason why specific cell-types are sensitive to KRAS mutations during cancer initiation.
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3
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Ras Isoforms from Lab Benches to Lives-What Are We Missing and How Far Are We? Int J Mol Sci 2021; 22:ijms22126508. [PMID: 34204435 PMCID: PMC8233758 DOI: 10.3390/ijms22126508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 11/21/2022] Open
Abstract
The central protein in the oncogenic circuitry is the Ras GTPase that has been under intense scrutiny for the last four decades. From its discovery as a viral oncogene and its non-oncogenic contribution to crucial cellular functioning, an elaborate genetic, structural, and functional map of Ras is being created for its therapeutic targeting. Despite decades of research, there still exist lacunae in our understanding of Ras. The complexity of the Ras functioning is further exemplified by the fact that the three canonical Ras genes encode for four protein isoforms (H-Ras, K-Ras4A, K-Ras4B, and N-Ras). Contrary to the initial assessment that the H-, K-, and N-Ras isoforms are functionally similar, emerging data are uncovering crucial differences between them. These Ras isoforms exhibit not only cell-type and context-dependent functions but also activator and effector specificities on activation by the same receptor. Preferential localization of H-, K-, and N-Ras in different microdomains of the plasma membrane and cellular organelles like Golgi, endoplasmic reticulum, mitochondria, and endosome adds a new dimension to isoform-specific signaling and diverse functions. Herein, we review isoform-specific properties of Ras GTPase and highlight the importance of considering these towards generating effective isoform-specific therapies in the future.
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Jiang W, Takeshita N, Maeda T, Sogi C, Oyanagi T, Kimura S, Yoshida M, Sasaki K, Ito A, Takano-Yamamoto T. Connective tissue growth factor promotes chemotaxis of preosteoblasts through integrin α5 and Ras during tensile force-induced intramembranous osteogenesis. Sci Rep 2021; 11:2368. [PMID: 33504916 PMCID: PMC7841149 DOI: 10.1038/s41598-021-82246-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 01/18/2021] [Indexed: 02/07/2023] Open
Abstract
In vertebrates, new bone formation via intramembranous osteogenesis is a critical biological event for development, remodeling, and fracture healing of bones. Chemotaxis of osteoblast lineage cells is an essential cellular process in new bone formation. Connective tissue growth factor (CTGF) is known to exert chemotactic properties on various cells; however, details of CTGF function in the chemotaxis of osteoblast lineage cells and underlying molecular biological mechanisms have not been clarified. The aim of the present study was to evaluate the chemotactic properties of CTGF and its underlying mechanisms during active bone formation through intramembranous osteogenesis. In our mouse tensile force-induced bone formation model, preosteoblasts were aggregated at the osteogenic front of calvarial bones. CTGF was expressed at the osteogenic front, and functional inhibition of CTGF using a neutralizing antibody suppressed the aggregation of preosteoblasts. In vitro experiments using μ-slide chemotaxis chambers showed that a gradient of CTGF induced chemotaxis of preosteoblastic MC3T3-E1 cells, while a neutralizing integrin α5 antibody and a Ras inhibitor inhibited the CTGF-induced chemotaxis of MC3T3-E1 cells. These findings suggest that the CTGF-integrin α5-Ras axis is an essential molecular mechanism to promote chemotaxis of preosteoblasts during new bone formation through intramembranous osteogenesis.
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Affiliation(s)
- Wei Jiang
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Nobuo Takeshita
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Toshihiro Maeda
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Chisumi Sogi
- Department of Pediatrics, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8574, Japan
| | - Toshihito Oyanagi
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Seiji Kimura
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Michiko Yoshida
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Kiyo Sasaki
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Arata Ito
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Teruko Takano-Yamamoto
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, 980-8575, Japan. .,Department of Biomaterials and Bioengineering, Faculty of Dental Medicine, Hokkaido University, Sapporo, Hokkaido, 060-8586, Japan.
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5
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Post JB, Roodhart JML, Snippert HJG. Colorectal Cancer Modeling with Organoids: Discriminating between Oncogenic RAS and BRAF Variants. Trends Cancer 2020; 6:111-129. [PMID: 32061302 DOI: 10.1016/j.trecan.2019.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 11/27/2019] [Accepted: 12/06/2019] [Indexed: 12/12/2022]
Abstract
RAS and BRAF proteins are frequently mutated in colorectal cancer (CRC) and have been associated with therapy resistance in metastatic CRC patients. RAS isoforms are considered to act as redundant entities in physiological and pathological settings. However, there is compelling evidence that mutant variants of RAS and BRAF have different oncogenic potentials and therapeutic outcomes. In this review we describe similarities and differences between various RAS and BRAF oncogenes in CRC development, histology, and therapy resistance. In addition, we discuss the potential of patient-derived tumor organoids for personalized therapy, as well as CRC modeling using genome editing in preclinical model systems to study similarities and discrepancies between the effects of oncogenic MAPK pathway mutations on tumor growth and drug response.
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Affiliation(s)
- Jasmin B Post
- Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht and Utrecht University, CX Utrecht, The Netherlands; Oncode Institute Netherlands, Office Jaarbeurs Innovation Mile, Utrecht, The Netherlands
| | - Jeanine M L Roodhart
- Department of Medical Oncology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands; Oncode Institute Netherlands, Office Jaarbeurs Innovation Mile, Utrecht, The Netherlands
| | - Hugo J G Snippert
- Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht and Utrecht University, CX Utrecht, The Netherlands; Oncode Institute Netherlands, Office Jaarbeurs Innovation Mile, Utrecht, The Netherlands.
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6
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Nishiyama J. Plasticity of dendritic spines: Molecular function and dysfunction in neurodevelopmental disorders. Psychiatry Clin Neurosci 2019; 73:541-550. [PMID: 31215705 DOI: 10.1111/pcn.12899] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 06/04/2019] [Accepted: 06/06/2019] [Indexed: 02/06/2023]
Abstract
Dendritic spines are tiny postsynaptic protrusions from a dendrite that receive most of the excitatory synaptic input in the brain. Functional and structural changes in dendritic spines are critical for synaptic plasticity, a cellular model of learning and memory. Conversely, altered spine morphology and plasticity are common hallmarks of human neurodevelopmental disorders, such as intellectual disability and autism. The advances in molecular and optical techniques have allowed for exploration of dynamic changes in structure and signal transduction at single-spine resolution, providing significant insights into the molecular regulation underlying spine structural plasticity. Here, I review recent findings on: how synaptic stimulation leads to diverse forms of spine structural plasticity; how the associated biochemical signals are initiated and transmitted into neuronal compartments; and how disruption of single genes associated with neurodevelopmental disorders can lead to abnormal spine structure in human and mouse brains. In particular, I discuss the functions of the Ras superfamily of small GTPases in spatiotemporal regulation of the actin cytoskeleton and protein synthesis in dendritic spines. Multiple lines of evidence implicate disrupted Ras signaling pathways in the spine structural abnormalities observed in neurodevelopmental disorders. Both deficient and excessive Ras activities lead to disrupted spine structure and deficits in learning and memory. Dysregulation of spine Ras signaling, therefore, may play a key role in the pathogenesis of multiple neurodevelopmental disorders with distinct etiologies.
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Affiliation(s)
- Jun Nishiyama
- Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore Medical School, Singapore
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7
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Oncogenic N-Ras Stimulates SRF-Mediated Transactivation via H3 Acetylation at Lysine 9. BIOMED RESEARCH INTERNATIONAL 2018; 2018:5473725. [PMID: 29511684 PMCID: PMC5817314 DOI: 10.1155/2018/5473725] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 10/18/2017] [Accepted: 11/21/2017] [Indexed: 01/10/2023]
Abstract
Signal transduction pathways regulate the gene expression by altering chromatin dynamics in response to mitogens. Ras proteins are key regulators linking extracellular stimuli to a diverse range of biological responses associated with gene regulation. In mammals, the three ras genes encode four Ras protein isoforms: H-Ras, K-Ras4A, K-Ras4B, and N-Ras. Although emerging evidence suggests that Ras isoforms differentially regulate gene expressions and are functionally nonredundant, the mechanisms underlying Ras specificity and Ras signaling effects on gene expression remain unclear. Here, we show that oncogenic N-Ras acts as the most potent regulator of SRF-, NF-κB-, and AP-1-dependent transcription. N-Ras-RGL2 axis is a distinct signaling pathway for SRF target gene expression such as Egr1 and JunB, as RGL2 Ras binding domain (RBD) significantly impaired oncogenic N-Ras-induced SRE activation. By monitoring the effect of Ras isoforms upon the change of global histone modifications in oncogenic Ras-overexpressed cells, we discovered that oncogenic N-Ras elevates H3K9ac/H3K23ac levels globally in the chromatin context. Importantly, chromatin immunoprecipitation (ChIP) assays revealed that H3K9ac is significantly enriched at the promoter and coding regions of Egr1 and JunB. Collectively, our findings define an undocumented role of N-Ras in modulating of H3 acetylation and in gene regulation.
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8
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Messina S, Di Zazzo E, Moncharmont B. Early and Late Induction of KRAS and HRAS Proto-Oncogenes by Reactive Oxygen Species in Primary Astrocytes. Antioxidants (Basel) 2017; 6:antiox6030048. [PMID: 28661467 PMCID: PMC5618076 DOI: 10.3390/antiox6030048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 06/17/2017] [Accepted: 06/19/2017] [Indexed: 12/13/2022] Open
Abstract
Astrocytes, one of the predominant types of glial cells, function as both supportive and metabolic cells for the brain. Among mammalian tissues, the highest levels of p21Ras protein are detected in the brain. Here, we investigated the expression of KRAS and HRAS proto-oncogenes in primary astrocytes following acute oxidative stimulation. Reactive oxygen species (ROS) changed the expression of proto-oncogenes at both transcriptional and translational levels. De novo protein synthesis analysis measured approximate values of proteins half-life, ranging from 1–4 h, of the different H- and K- isoforms by western blot analysis. Quantitative gene expression analysis of KRAS and HRAS revealed an unexpected short-term induction of KRAS mRNA in primary astrocytes in response to acute stimulation. Indeed, cultured astrocytes responded to proteasomal inhibition by preventing the reduction of c-K-Ras. A fraction of K-Ras protein accumulated in the presence of ROS and cycloheximide, while a substantial proportion was continuously synthesized. These data indicate that ROS regulate in a complementary fashion p21Ras isoforms in primary astrocytes: K-Ras is rapidly and transiently induced by post-translational and post-transcriptional mechanisms, while H-Ras is stably induced by mRNA accumulation. We suggest that K-Ras and H-Ras are ROS sensors that adapt cells to metabolic needs and oxidative stress.
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Affiliation(s)
- Samantha Messina
- Department of Human Sciences, Society and Health, University of Cassino and Southern Lazio, Cassino 03043, Italy.
| | - Erika Di Zazzo
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso 86100, Italy.
| | - Bruno Moncharmont
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso 86100, Italy.
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9
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Watters K, Inankur B, Gardiner JC, Warrick J, Sherer NM, Yin J, Palmenberg AC. Differential Disruption of Nucleocytoplasmic Trafficking Pathways by Rhinovirus 2A Proteases. J Virol 2017; 91:e02472-16. [PMID: 28179529 PMCID: PMC5375692 DOI: 10.1128/jvi.02472-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 02/01/2017] [Indexed: 01/11/2023] Open
Abstract
The RNA rhinoviruses (RV) encode 2A proteases (2Apro) that contribute essential polyprotein processing and host cell shutoff functions during infection, including the cleavage of Phe/Gly-containing nucleoporin proteins (Nups) within nuclear pore complexes (NPC). Within the 3 RV species, multiple divergent genotypes encode diverse 2Apro sequences that act differentially on specific Nups. Since only subsets of Phe/Gly motifs, particularly those within Nup62, Nup98, and Nup153, are recognized by transport receptors (karyopherins) when trafficking large molecular cargos through the NPC, the processing preferences of individual 2Apro predict RV genotype-specific targeting of NPC pathways and cargos. To test this idea, transformed HeLa cell lines were created with fluorescent cargos (mCherry) for the importin α/β, transportin 1, and transportin 3 import pathways and the Crm1-mediated export pathway. Live-cell imaging of single cells expressing recombinant RV 2Apro (A16, A45, B04, B14, B52, C02, and C15) showed disruption of each pathway with measurably different efficiencies and reaction rates. The B04 and B52 proteases preferentially targeted Nups in the import pathways, while B04 and C15 proteases were more effective against the export pathway. Virus-type-specific trends were also observed during infection of cells with A16, B04, B14, and B52 viruses or their chimeras, as measured by NF-κB (p65/Rel) translocation into the nucleus and the rates of virus-associated cytopathic effects. This study provides new tools for evaluating the host cell response to RV infections in real time and suggests that differential 2Apro activities explain, in part, strain-dependent host responses and diverse RV disease phenotypes.IMPORTANCE Genetic variation among human rhinovirus types includes unexpected diversity in the genes encoding viral proteases (2Apro) that help these viruses achieve antihost responses. When the enzyme activities of 7 different 2Apro were measured comparatively in transformed cells programed with fluorescent reporter systems and by quantitative cell imaging, the cellular substrates, particularly in the nuclear pore complex, used by these proteases were indeed attacked at different rates and with different affinities. The importance of this finding is that it provides a mechanistic explanation for how different types (strains) of rhinoviruses may elicit different cell responses that directly or indirectly lead to distinct disease phenotypes.
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Affiliation(s)
- Kelly Watters
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Bahar Inankur
- Wisconsin Institutes for Discovery and Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jaye C Gardiner
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- McArdle Laboratories for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jay Warrick
- Wisconsin Institutes for Medical Research and Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Nathan M Sherer
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- McArdle Laboratories for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - John Yin
- Wisconsin Institutes for Discovery and Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Ann C Palmenberg
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
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10
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Dorard C, Vucak G, Baccarini M. Deciphering the RAS/ERK pathway in vivo. Biochem Soc Trans 2017; 45:27-36. [PMID: 28202657 DOI: 10.1042/bst20160135] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 11/03/2016] [Accepted: 11/07/2016] [Indexed: 12/19/2022]
Abstract
The RAS/ERK pathway has been intensely studied for about three decades, not least because of its role in human pathologies. ERK activation is observed in the majority of human cancers; in about one-third of them, it is driven by mutational activation of pathway components. The pathway is arguably one of the best targets for molecule-based pharmacological intervention, and several small-molecule inhibitors are in clinical use. Genetically engineered mouse models have greatly contributed to our understanding of signaling pathways in development, tissue homeostasis, and disease. In the specific case of the RAS/ERK pathway, they have revealed unique biological roles of structurally and functionally similar proteins, new kinase-independent effectors, and unsuspected relationships with other cascades. This short review summarizes the contribution of mouse models to our current understanding of the pathway.
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Affiliation(s)
- Coralie Dorard
- Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna 1030, Austria
| | - Georg Vucak
- Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna 1030, Austria
| | - Manuela Baccarini
- Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna 1030, Austria
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11
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Quantification of spatiotemporal patterns of Ras isoform expression during development. Sci Rep 2017; 7:41297. [PMID: 28117393 PMCID: PMC5259795 DOI: 10.1038/srep41297] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 12/19/2016] [Indexed: 01/05/2023] Open
Abstract
Ras proteins are important signalling hubs frequently dysregulated in cancer and in a group of developmental disorders called Rasopathies. Three Ras genes encode four proteins that differentially contribute to these phenotypes. Using quantitative real-time PCR (qRT-PCR) we have measured the gene expression profiles of each of the Ras isoforms in a panel of mouse tissues derived from a full developmental time course spanning embryogenesis through to adulthood. In most tissues and developmental stages we observe a relative contribution of KRas4B > > NRas ≥ KRas4A > HRas to total Ras expression with KRas4B typically representing 60–99% of all Ras transcripts. KRas4A is the most dynamically regulated Ras isoform with significant up-regulation of expression observed pre-term in stomach, intestine, kidney and heart. The expression patterns assist interpretation of the essential role of KRas in development and the preponderance of KRas mutations in cancer.
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12
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Anta B, Pérez-Rodríguez A, Castro J, García-Domínguez CA, Ibiza S, Martínez N, Durá LM, Hernández S, Gragera T, Peña-Jiménez D, Yunta M, Zarich N, Crespo P, Serrador JM, Santos E, Muñoz A, Oliva JL, Rojas-Cabañeros JM. PGA1-induced apoptosis involves specific activation of H-Ras and N-Ras in cellular endomembranes. Cell Death Dis 2016; 7:e2311. [PMID: 27468687 PMCID: PMC4973357 DOI: 10.1038/cddis.2016.219] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 06/20/2016] [Accepted: 06/21/2016] [Indexed: 12/14/2022]
Abstract
The cyclopentenone prostaglandin A1 (PGA1) is an inducer of cell death in cancer cells. However, the mechanism that initiates this cytotoxic response remains elusive. Here we report that PGA1 triggers apoptosis by a process that entails the specific activation of H- and N-Ras isoforms, leading to caspase activation. Cells without H- and N-Ras did not undergo apoptosis upon PGA1 treatment; in these cells, the cellular demise was rescued by overexpression of either H-Ras or N-Ras. Consistently, the mutant H-Ras-C118S, defective for binding PGA1, did not produce cell death. Molecular analysis revealed a key role for the RAF-MEK-ERK signaling pathway in the apoptotic process through the induction of calpain activity and caspase-12 cleavage. We propose that PGA1 evokes a specific physiological cell death program, through H- and N-Ras, but not K-Ras, activation at endomembranes. Our results highlight a novel mechanism that may be of potential interest for tumor treatment.
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Affiliation(s)
- B Anta
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - A Pérez-Rodríguez
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - J Castro
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - C A García-Domínguez
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - S Ibiza
- Fundación Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid 28029, Spain
| | - N Martínez
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - L M Durá
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - S Hernández
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - T Gragera
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - D Peña-Jiménez
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - M Yunta
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - N Zarich
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - P Crespo
- Departamento de Biologia Molecular, Facultad de Medicina, Instituto de Biomedicina y Biotecnología de Cantabria, Consejo Superior de Investigaciones Cientificas (CSIC)-IDICAN, Universidad de Cantabria, Santander 39011, Spain
| | - J M Serrador
- Departamento de Biología Celular e Inmunología, Centro de Biología Molecular Severo Ochoa (CBMSO), CSIC-UAM, Madrid 28049, Spain
| | - E Santos
- Centro de Investigación del Cancer, IBMCC (CSIC-USAL), Universidad de Salamanca, Salamanca 37007, Spain
| | - A Muñoz
- Instituto de Investigaciones Biomédicas 'Alberto Sols', Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Arturo Duperier 4, Madrid 28029, Spain
| | - J L Oliva
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
| | - J M Rojas-Cabañeros
- Unidad de Biología Celular, Unidad Funcional de Investigación de Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, Madrid 28220, Spain
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13
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Ryu HH, Lee YS. Cell type-specific roles of RAS-MAPK signaling in learning and memory: Implications in neurodevelopmental disorders. Neurobiol Learn Mem 2016; 135:13-21. [PMID: 27296701 DOI: 10.1016/j.nlm.2016.06.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 05/28/2016] [Accepted: 06/09/2016] [Indexed: 01/17/2023]
Abstract
The RAS-mitogen-activated protein kinase (MAPK) signaling pathway plays critical roles in brain function, including learning and memory. Mutations of molecules in the RAS-MAPK pathway are associated with a group of disorders called RASopathies, which include Noonan syndrome, neurofibromatosis type 1, Costello syndrome, Noonan syndrome with multiple lentigines, Legius syndrome, and cardio-facio-cutaneous syndrome. RASopathies share certain clinical symptoms, including craniofacial abnormalities, heart defects, delayed growth, and cognitive deficits such as learning disabilities, while each individual syndrome also displays unique phenotypes. Recent studies using mouse models of RASopathies showed that each disorder may have a distinct molecular and cellular etiology depending on the cellular specificity of the mutated molecules. Here, we review the cell-type specific roles of the regulators of the RAS-MAPK pathway in cognitive function (learning and memory) and their contribution to the development of RASopathies. We also discussed recent technical advances in analyzing cell type-specific transcriptomes and proteomes in the nervous system. Understanding specific mechanisms for these similar but distinct disorders would facilitate the development of mechanism-based individualized treatment for RASopathies.
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Affiliation(s)
- Hyun-Hee Ryu
- Department of Life Science, College of Natural Science, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 06974, South Korea; Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Yong-Seok Lee
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.
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Wang MT, Holderfield M, Galeas J, Delrosario R, To MD, Balmain A, McCormick F. K-Ras Promotes Tumorigenicity through Suppression of Non-canonical Wnt Signaling. Cell 2016; 163:1237-1251. [PMID: 26590425 DOI: 10.1016/j.cell.2015.10.041] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/01/2015] [Accepted: 10/13/2015] [Indexed: 12/30/2022]
Abstract
K-Ras and H-Ras share identical effectors and have similar properties; however, the high degree of tumor-type specificity associated with K-Ras and H-Ras mutations suggests that they have unique roles in oncogenesis. Here, we report that oncogenic K-Ras, but not H-Ras, suppresses non-canonical Wnt/Ca(2+) signaling, an effect that contributes strongly to its tumorigenic properties. K-Ras does this by binding to calmodulin and so reducing CaMKii activity and expression of Fzd8. Restoring Fzd8 in K-Ras mutant pancreatic cells suppresses malignancy, whereas depletion of Fzd8 in H-Ras(V12)-transformed cells enhances their tumor initiating capacity. Interrupting K-Ras-calmodulin binding using genetic means or by treatment with an orally active protein kinase C (PKC)-activator, prostratin, represses tumorigenesis in K-Ras mutant pancreatic cancer cells. These findings provide an alternative way to selectively target this "undruggable" protein.
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Affiliation(s)
- Man-Tzu Wang
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Matthew Holderfield
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Jacqueline Galeas
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Reyno Delrosario
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Minh D To
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Allan Balmain
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA
| | - Frank McCormick
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, 1450 3(rd) Street, San Francisco, CA 94158, USA.
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Mageean CJ, Griffiths JR, Smith DL, Clague MJ, Prior IA. Absolute Quantification of Endogenous Ras Isoform Abundance. PLoS One 2015; 10:e0142674. [PMID: 26560143 PMCID: PMC4641634 DOI: 10.1371/journal.pone.0142674] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/26/2015] [Indexed: 01/15/2023] Open
Abstract
Ras proteins are important signalling hubs situated near the top of networks controlling cell proliferation, differentiation and survival. Three almost identical isoforms, HRAS, KRAS and NRAS, are ubiquitously expressed yet have differing biological and oncogenic properties. In order to help understand the relative biological contributions of each isoform we have optimised a quantitative proteomics method for accurately measuring Ras isoform protein copy number per cell. The use of isotopic protein standards together with selected reaction monitoring for diagnostic peptides is sensitive, robust and suitable for application to sub-milligram quantities of lysates. We find that in a panel of isogenic SW48 colorectal cancer cells, endogenous Ras proteins are highly abundant with ≥260,000 total Ras protein copies per cell and the rank order of isoform abundance is KRAS>NRAS≥HRAS. A subset of oncogenic KRAS mutants exhibit increased total cellular Ras abundance and altered the ratio of mutant versus wild type KRAS protein. These data and methodology are significant because Ras protein copy number is required to parameterise models of signalling networks and informs interpretation of isoform-specific Ras functional data.
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Affiliation(s)
- Craig J. Mageean
- Division of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3BX, United Kingdom
| | - John R. Griffiths
- Cancer Research UK Manchester Institute, University of Manchester, Manchester, M20 4BX, United Kingdom
| | - Duncan L. Smith
- Cancer Research UK Manchester Institute, University of Manchester, Manchester, M20 4BX, United Kingdom
| | - Michael J. Clague
- Division of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3BX, United Kingdom
| | - Ian A. Prior
- Division of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3BX, United Kingdom
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Lynch SJ, Snitkin H, Gumper I, Philips MR, Sabatini D, Pellicer A. The differential palmitoylation states of N-Ras and H-Ras determine their distinct Golgi subcompartment localizations. J Cell Physiol 2015; 230:610-9. [PMID: 25158650 PMCID: PMC4269384 DOI: 10.1002/jcp.24779] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 08/22/2014] [Indexed: 01/27/2023]
Abstract
Despite a high degree of structural homology and shared exchange factors, effectors and GTPase activating proteins, a large body of evidence suggests functional heterogeneity among Ras isoforms. One aspect of Ras biology that may explain this heterogeneity is the differential subcellular localizations driven by the C-terminal hypervariable regions of Ras proteins. Spatial heterogeneity has been documented at the level of organelles: palmitoylated Ras isoforms (H-Ras and N-Ras) localize on the Golgi apparatus whereas K-Ras4B does not. We tested the hypothesis that spatial heterogeneity also exists at the sub-organelle level by studying the localization of differentially palmitoylated Ras isoforms within the Golgi apparatus. Using confocal, live-cell fluorescent imaging and immunogold electron microscopy we found that, whereas the doubly palmitoylated H-Ras is distributed throughout the Golgi stacks, the singly palmitoylated N-Ras is polarized with a relative paucity of expression on the trans Golgi. Using palmitoylation mutants, we show that the different sub-Golgi distributions of the Ras proteins are a consequence of their differential degree of palmitoylation. Thus, the acylation state of Ras proteins controls not only their distribution between the Golgi apparatus and the plasma membrane, but also their distribution within the Golgi stacks.
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Affiliation(s)
- Stephen J. Lynch
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - Harriet Snitkin
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | - Iwona Gumper
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | - Mark R. Philips
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA
- Department of Medicine, New York University School of Medicine, New York, NY, USA
- Department of Pharmacology, New York University School of Medicine, New York, NY, USA
- New York University Cancer Institute, New York University School of Medicine, New York, NY, USA
| | - David Sabatini
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | - Angel Pellicer
- Department of Pathology, New York University School of Medicine, New York, NY, USA
- New York University Cancer Institute, New York University School of Medicine, New York, NY, USA
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Rapozzi V, Zorzet S, Zacchigna M, Della Pietra E, Cogoi S, Xodo LE. Anticancer activity of cationic porphyrins in melanoma tumour-bearing mice and mechanistic in vitro studies. Mol Cancer 2014; 13:75. [PMID: 24684778 PMCID: PMC4021972 DOI: 10.1186/1476-4598-13-75] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 03/20/2014] [Indexed: 01/07/2023] Open
Abstract
Background Porphyrin TMPyP4 (P4) and its C14H28-alkyl derivative (C14) are G-quadruplex binders and singlet oxygen (1O2) generators. In contrast, TMPyP2 (P2) produces 1O2 but it is not a G-quadruplex binder. As their photosensitizing activity is currently undefined, we report in this study their efficacy against a melanoma skin tumour and describe an in vitro mechanistic study which gives insights into their anticancer activity. Methods Uptake and antiproliferative activity of photoactivated P2, P4 and C14 have been investigated in murine melanoma B78-H1 cells by FACS, clonogenic and migration assays. Apoptosis was investigated by PARP-1 cleavage and annexin-propidium iodide assays. Biodistribution and in vivo anticancer activity were tested in melanoma tumour-bearing mice. Porphyrin binding and photocleavage of G-rich mRNA regions were investigated by electrophoresis and RT-PCR. Porphyrin effect on ERK pathway was explored by Western blots. Results Thanks to its higher lipophylicity C14 was taken up by murine melanoma B78-H1 cells up to 30-fold more efficiently than P4. When photoactivated (7.2 J/cm2) in B78-H1 melanoma cells, P4 and C14, but not control P2, caused a strong inhibition of metabolic activity, clonogenic growth and cell migration. Biodistribution studies on melanoma tumour-bearing mice showed that P4 and C14 localize in the tumour. Upon irradiation (660 nm, 193 J/cm2), P4 and C14 retarded tumour growth and increased the median survival time of the treated mice by ~50% (P <0.01 by ANOVA), whereas porphyrin P2 did not. The light-dependent mechanism mediated by P4 and C14 is likely due to the binding to and photocleavage of G-rich quadruplex-forming sequences within the 5′-untranslated regions of the mitogenic ras genes. This causes a decrease of RAS protein and inhibition of downstream ERK pathway, which stimulates proliferation. Annexin V/propidium iodide and PARP-1 cleavage assays showed that the porphyrins arrested tumour growth by apoptosis and necrosis. C14 also showed an intrinsic light-independent anticancer activity, as recently reported for G4-RNA binders. Conclusions Porphyrins P4 and C14 impair the clonogenic growth and migration of B78-H1 melanoma cells and inhibit melanoma tumour growth in vivo. Evidence is provided that C14 acts through light-dependent (mRNA photocleavage) and light-independent (translation inhibition) mechanisms.
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Affiliation(s)
| | | | | | | | | | - Luigi E Xodo
- Department of Medical and Biological Sciences, School of Medicine, P,le Kolbe 4, 33100 Udine, Italy.
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18
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Fuentes-Calvo I, Crespo P, Santos E, López-Novoa JM, Martínez-Salgado C. The small GTPase N-Ras regulates extracellular matrix synthesis, proliferation and migration in fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2734-2744. [DOI: 10.1016/j.bbamcr.2013.07.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 07/09/2013] [Accepted: 07/10/2013] [Indexed: 01/22/2023]
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19
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Chen X, Makarewicz JM, Knauf JA, Johnson LK, Fagin JA. Transformation by Hras(G12V) is consistently associated with mutant allele copy gains and is reversed by farnesyl transferase inhibition. Oncogene 2013; 33:5442-9. [PMID: 24240680 PMCID: PMC4025988 DOI: 10.1038/onc.2013.489] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 10/04/2013] [Accepted: 10/08/2013] [Indexed: 01/19/2023]
Abstract
RAS-driven malignancies remain a major therapeutic challenge. The two-stage 7,12-dimethylbenz(a)anthracene (DMBA)/12-o-tetradecanoylphorbol-13-acetate (TPA) model of mouse skin carcinogenesis has been used to study mechanisms of epithelial tumor development by oncogenic Hras. We used mice with a HrasG12V knock-in allele to elucidate the early events after Hras activation, and to evaluate the therapeutic effectiveness of farnesyltransferase (FTI) inhibition. Treatment of Caggs-Cre/FR-HrasG12V mice with TPA alone was sufficient to trigger papilloma development with shorter latency and a ~10-fold greater tumor burden than DMBA/TPA-treated WT controls. HrasG12V allele copy number was increased in all papillomas induced by TPA. DMBA/TPA treatment of HrasG12V knock-in mice induced an even greater incidence of papillomas, which either harbored HrasG12V amplification, or developed a HrasQ61L mutation in the second allele. Laser-capture microdissection of normal skin, hyperplastic skin and papillomas showed that amplification occurred only at the papilloma stage. HRAS mutant allelic imbalance was also observed in human cancer cell lines, consistent with a requirement for augmented oncogenic HRAS signaling for tumor development. The FTI SCH66336 blocks HRAS farnesylation and delocalizes it from the plasma membrane. NRAS and KRAS are not affected as they are alternatively prenylated. When tested in lines harboring HRAS, NRAS or KRAS mutations, SCH66336 delocalized, inhibited signaling and preferentially inhibited growth only of HRAS-mutant lines. Treatment with SCH66336 also induced near-complete regression of papillomas of TPA-treated HrasG12V knock-in mice. These data suggest that farnesyl transferase inhibitors should be reevaluated as targeted agents for human HRAS-driven cancers, such as those of bladder, thyroid and other epithelial lineages.
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Affiliation(s)
- X Chen
- Human Oncology and Pathogenesis Program, Sloan Kettering Cancer Center, New York, NY, USA
| | - J M Makarewicz
- Human Oncology and Pathogenesis Program, Sloan Kettering Cancer Center, New York, NY, USA
| | - J A Knauf
- 1] Human Oncology and Pathogenesis Program, Sloan Kettering Cancer Center, New York, NY, USA [2] Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - L K Johnson
- Sloan Kettering Institute, New York, NY, USA
| | - J A Fagin
- 1] Human Oncology and Pathogenesis Program, Sloan Kettering Cancer Center, New York, NY, USA [2] Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA [3] Weill-Cornell Medical College, New York, NY, USA
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20
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Le Floc'h A, Tanaka Y, Bantilan NS, Voisinne G, Altan-Bonnet G, Fukui Y, Huse M. Annular PIP3 accumulation controls actin architecture and modulates cytotoxicity at the immunological synapse. ACTA ACUST UNITED AC 2013; 210:2721-37. [PMID: 24190432 PMCID: PMC3832928 DOI: 10.1084/jem.20131324] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
In T cells, PI3K activation in the periphery of the immune synapse leads to PIP3 accumulation that promotes actin polymerization in a pathway important for cytotoxic function. The immunological synapse formed by a T lymphocyte on the surface of a target cell contains a peripheral ring of filamentous actin (F-actin) that promotes adhesion and facilitates the directional secretion of cytokines and cytolytic factors. We show that growth and maintenance of this F-actin ring is dictated by the annular accumulation of phosphatidylinositol trisphosphate (PIP3) in the synaptic membrane. PIP3 functions in this context by recruiting the exchange factor Dock2 to the periphery of the synapse, where it drives actin polymerization through the Rho-family GTPase Rac. We also show that synaptic PIP3 is generated by class IA phosphoinositide 3-kinases that associate with T cell receptor microclusters and are activated by the GTPase Ras. Perturbations that inhibit or promote PIP3-dependent F-actin remodeling dramatically affect T cell cytotoxicity, demonstrating the functional importance of this pathway. These results reveal how T cells use lipid-based signaling to control synaptic architecture and modulate effector responses.
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Affiliation(s)
- Audrey Le Floc'h
- Immunology Program, 2 Computational Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065
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21
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Lau KS, Schrier SB, Gierut J, Lyons J, Lauffenburger DA, Haigis KM. Network analysis of differential Ras isoform mutation effects on intestinal epithelial responses to TNF-α. Integr Biol (Camb) 2013; 5:1355-65. [PMID: 24084984 DOI: 10.1039/c3ib40062j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Tumor necrosis factor alpha (TNF-α) is an inflammatory cytokine that can elicit distinct cellular behaviors under different molecular contexts. Mitogen activated protein kinase (MAPK) pathways, especially the extracellular signal-regulated kinase (Erk) pathway, help to integrate influences from the environmental context, and therefore modulate the phenotypic effect of TNF-α exposure. To test how variations in flux through the Erk pathway modulate TNF-α-elicited phenotypes in a complex physiological environment, we exposed mice with different Ras mutations (K-Ras activation, N-Ras activation, and N-Ras ablation) to TNF-α and observed phenotypic and signaling changes in the intestinal epithelium. Hyperactivation of Mek1, an Erk kinase, was observed in the intestine of mice with K-Ras activation and, surprisingly, in N-Ras null mice. Nevertheless, these similar Mek1 outputs did not give rise to the same phenotype, as N-Ras null intestine was hypersensitive to TNF-α-induced intestinal cell death while K-Ras mutant intestine was not. A systems biology approach applied to sample the network state revealed that the signaling contexts presented by these two Ras isoform mutations were different. Consistent with our experimental data, N-Ras ablation induced a signaling network state that was mathematically predicted to be pro-death, while K-Ras activation did not. Further modeling by constrained Fuzzy Logic (cFL) revealed that N-Ras and K-Ras activate the signaling network with different downstream distributions and dynamics, with N-Ras effects being more transient and diverted more towards PI3K-Akt signaling and K-Ras effects being more sustained and broadly activating many pathways. Our study highlights the necessity to consider both environmental and genomic contexts of signaling pathway activation in dictating phenotypic responses, and demonstrates how modeling can provide insight into complex in vivo biological mechanisms, such as the complex interplay between K-Ras and N-Ras in their downstream effects.
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Affiliation(s)
- Ken S Lau
- Molecular Pathology Unit, Center for Cancer Research, and Center for Systems Biology, Massachusetts General Hospital, 149 13th Street, Charlestown, MA 02129, USA.
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Lynch SJ, Zavadil J, Pellicer A. In TCR-stimulated T-cells, N-ras regulates specific genes and signal transduction pathways. PLoS One 2013; 8:e63193. [PMID: 23755101 PMCID: PMC3670928 DOI: 10.1371/journal.pone.0063193] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 04/02/2013] [Indexed: 12/27/2022] Open
Abstract
It has been recently shown that N-ras plays a preferential role in immune cell development and function; specifically: N-ras, but not H-ras or K-ras, could be activated at and signal from the Golgi membrane of immune cells following a low level T-cell receptor stimulus. The goal of our studies was to test the hypothesis that N-ras and H-ras played distinct roles in immune cells at the level of the transcriptome. First, we showed via mRNA expression profiling that there were over four hundred genes that were uniquely differentially regulated either by N-ras or H-ras, which provided strong evidence in favor of the hypothesis that N-ras and H-ras have distinct functions in immune cells. We next characterized the genes that were differentially regulated by N-ras in T cells following a low-level T-cell receptor stimulus. Of the large pool of candidate genes that were differentially regulated by N-ras downstream of TCR ligation, four genes were verified in qRT-PCR-based validation experiments (Dntt, Slc9a6, Chst1, and Lars2). Finally, although there was little overlap between individual genes that were regulated by N-ras in unstimulated thymocytes and stimulated CD4+ T-cells, there was a nearly complete correspondence between the signaling pathways that were regulated by N-ras in these two immune cell types.
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Affiliation(s)
- Stephen J. Lynch
- Department of Pathology, New York University Langone School of Medicine, New York, New York, United States of America
| | - Jiri Zavadil
- Department of Pathology, N.Y.U. Cancer Institute and Center for Health Informatics and Bioinformatics, New York University Langone Medical Center, New York, New York, United States of America
| | - Angel Pellicer
- Department of Pathology, New York University Langone School of Medicine, New York, New York, United States of America
- New York University Cancer Institute, New York University Langone School of Medicine, New York, New York, United States of America
- * E-mail:
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Fuentes-Calvo I, Blázquez-Medela AM, Eleno N, Santos E, López-Novoa JM, Martínez-Salgado C. H-Ras isoform modulates extracellular matrix synthesis, proliferation, and migration in fibroblasts. Am J Physiol Cell Physiol 2011; 302:C686-97. [PMID: 22094331 DOI: 10.1152/ajpcell.00103.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ras GTPases are ubiquitous plasma membrane transducers of extracellular stimuli. In addition to their role as oncogenes, Ras GTPases are key regulators of cell function. Each of the Ras isoforms exhibits specific modulatory activity on different cellular pathways. This has prompted researchers to determine the pathophysiological roles of each isoform. There is a proven relationship between the signaling pathways of transforming growth factor-β1 (TGF-β1) and Ras GTPases. To assess the individual role of H-Ras oncogene in basal and TGF-β1-mediated extracellular matrix (ECM) synthesis, proliferation, and migration in fibroblasts, we analyzed these processes in embryonic fibroblasts obtained from H-Ras knockout mice (H-ras(-/-)). We found that H-ras(-/-) fibroblasts exhibited a higher basal phosphatidylinositol-3-kinase (PI3K)/Akt activation than wild-type (WT) fibroblasts, whereas MEK/ERK 1/2 activation was similar in both types of cells. Fibronectin and collagen synthesis were higher in H-ras(-/-) fibroblasts and proliferation was lower in H-ras(-/-) than in WT fibroblasts. Moreover, H-Ras appeared indispensable to maintain normal fibroblast motility, which was highly restricted in H-ras(-/-) cells. These results suggest that H-Ras (through downregulation of PI3K/Akt activation) could modulate fibroblast activity by reducing ECM synthesis and upregulating both proliferation and migration. TGF-β1 strongly increased ERK and Akt activation in WT but not in H-ras(-/-) fibroblasts, suggesting that H-Ras is necessary to increase ERK 1/2 activation and to maintain PI3K downregulation in TGF-β1-stimulated fibroblasts. TGF-β1 stimulated ECM synthesis and proliferation, although ECM synthesis was higher and proliferation lower in H-ras(-/-) than in WT fibroblasts. Hence, H-Ras activation seems to play a key role in the regulation of these effects.
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Affiliation(s)
- Isabel Fuentes-Calvo
- Unidad de Fisiopatología Renal y Cardiovascular, Instituto “Reina Sofía” de Investigación Nefrológica, Departamento de Fisiología y Farmacología, Universidad de Salamanca, Salamanca, Spain
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24
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Grande MT, Arévalo M, Núñez A, Cannata-Andía JB, Santos E, López-Novoa JM. Targeted genomic disruption of H-ras and N-ras has no effect on early renal changes after unilateral ureteral ligation. World J Urol 2011; 27:787-97. [PMID: 19288266 DOI: 10.1007/s00345-009-0399-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2008] [Accepted: 02/23/2009] [Indexed: 11/28/2022] Open
Abstract
PURPOSE To assess the contribution of two different Ras monomeric GTPases isoforms H- and N-Ras in the early changes associated to obstructive nephropathy induced by unilateral ureteral obstruction (UUO). METHODS UUO was performed in N-ras (N-ras−/−) and H-ras (H-ras−/−) knock-out mice and control (H-ras+/+/N-ras+/+) mice of C57Bl/6 background. Fibronectin, α-smooth muscle actin, cleaved caspase-3, ki-67, Ras-GTP, pERK, and pAkt expression was analyzed by western blot and/or immunohistochemistry. Ras isoforms activation and caspase activity were determined by both western blot and ELISA. RESULTS Three days after UUO, obstructed (O) kidneys of H-ras−/−, N-ras−/−and H-ras+/+/N-ras+/+mice showed no significant differences in activated total ras, pERK1/2, pAkt, total Akt levels, fibronectin, α-SMA expression, cell proliferation, and activated caspase-3. The morphological alterations in the O kidneys, revealed by histological and immunohistochemical studies, were also similar in H-ras−/−, N-ras−/−, and H-ras+/+/N-ras+/+mice. CONCLUSIONS These data suggest that the activation of H-ras and N-ras isoforms does not play a major role in the early renal damage induced by UUO.
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Affiliation(s)
- María T Grande
- Departamento de Fisiología y Farmacología, Instituto Reina Sofía de Investigación Nefrológica, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007 Salamanca, Spain
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Luwor RB, Lu Y, Li X, Liang K, Fan Z. Constitutively active Harvey Ras confers resistance to epidermal growth factor receptor-targeted therapy with cetuximab and gefitinib. Cancer Lett 2011; 306:85-91. [PMID: 21411223 DOI: 10.1016/j.canlet.2011.02.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 02/17/2011] [Accepted: 02/21/2011] [Indexed: 01/05/2023]
Abstract
Kirsten Ras (K-Ras) mutations have been implicated as a key predictive marker of resistance to therapies targeting the epidermal growth factor receptor (EGFR). To determine whether Harvey Ras (H-Ras) mutations also can confer resistance to EGFR-targeted therapy, we expressed a constitutively active H-Ras (Ras G12V) in A431 human vulvar squamous carcinoma cells. Compared with corresponding control cells, A431-Ras cells exhibited marked resistance to the EGFR inhibitors cetuximab and gefitinib, reducing inhibition of Akt and Erk phosphorylation, inhibition of HIF-1α expression and transcriptional activity, and antitumor effects in vitro and in vivo. Our data indicate that constitutively active H-Ras can also confer resistance to anti-EGFR therapy in cancer cells.
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Affiliation(s)
- Rodney B Luwor
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, 77030, USA
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26
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Ray KC, Bell KM, Yan J, Gu G, Chung CH, Washington MK, Means AL. Epithelial tissues have varying degrees of susceptibility to Kras(G12D)-initiated tumorigenesis in a mouse model. PLoS One 2011; 6:e16786. [PMID: 21311774 PMCID: PMC3032792 DOI: 10.1371/journal.pone.0016786] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 01/11/2011] [Indexed: 02/06/2023] Open
Abstract
Activating mutations in the Kras gene are commonly found in some but not all epithelial cancers. In order to understand the susceptibility of different epithelial tissues to Kras-induced tumorigenesis, we introduced one of the most common Kras mutations, KrasG12D, broadly in epithelial tissues. We used a mouse model in which the G12D mutation is placed in the endogenous Kras locus controlled by inducible, Cre-mediated recombination in tissues expressing cytokeratin 19 including the oral cavity, GI tract, lungs, and ducts of the liver, kidney, and the pancreas. Introduction of the KrasG12D mutation in adult mouse tissues led to neoplastic changes in some but not all of these tissues. Notably, many hyperplasias, metaplasias and adenomas were observed in the oral cavity, stomach, colon and lungs, suggesting that exposure to products of the outside environment promotes KrasG12D-initiated tumorigenesis. However, environmental exposure did not consistently correlate with tumor formation, such as in the small intestine, suggesting that there are also intrinsic differences in susceptibility to Kras activation. The pancreas developed small numbers of mucinous metaplasias with characteristics of early stage pancreatic intraepithelial neoplasms (PanINs), supporting the hypothesis that pancreatic ducts have the potential to give rise pancreatic cancer.
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Affiliation(s)
- Kevin C Ray
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
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Beronja S, Livshits G, Williams S, Fuchs E. Rapid functional dissection of genetic networks via tissue-specific transduction and RNAi in mouse embryos. Nat Med 2010; 16:821-7. [PMID: 20526348 DOI: 10.1038/nm.2167] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 01/15/2010] [Indexed: 12/13/2022]
Abstract
Using ultrasound-guided in utero infections of fluorescently traceable lentiviruses carrying RNAi or Cre recombinase into mouse embryos, we have demonstrated noninvasive, highly efficient selective transduction of surface epithelium, in which progenitors stably incorporate and propagate the desired genetic alterations. We achieved epidermal-specific infection using small generic promoters of existing lentiviral short hairpin RNA libraries, thus enabling rapid assessment of gene function as well as complex genetic interactions in skin morphogenesis and disease in vivo. We adapted this technology to devise a new quantitative method for ascertaining whether a gene confers a growth advantage or disadvantage in skin tumorigenesis. Using alpha1-catenin as a model, we uncover new insights into its role as a widely expressed tumor suppressor and reveal physiological interactions between Ctnna1 and the Hras1-Mapk3 and Trp53 gene pathways in regulating skin cell proliferation and apoptosis. Our study illustrates the strategy and its broad applicability for investigations of tissue morphogenesis, lineage specification and cancers.
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Affiliation(s)
- Slobodan Beronja
- Howard Hughes Medical Institute, Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, New York, USA
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Castellano E, Downward J. Role of RAS in the regulation of PI 3-kinase. Curr Top Microbiol Immunol 2010; 346:143-69. [PMID: 20563706 DOI: 10.1007/82_2010_56] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Ras proteins are key regulators of signalling cascades, controlling many processes such as proliferation, differentiation and apoptosis. Mutations in these proteins or in their effectors, activators and regulators are associated with pathological conditions, particularly the development of various forms of human cancer. RAS proteins signal through direct interaction with a number of effector enzymes, one of the best characterized being type I phosphatidylinositol (PI) 3-kinases. Although the ability of RAS to control PI 3-kinase has long been well established in cultured cells, evidence for a role of the interaction of endogenous RAS with PI 3-kinase in normal and malignant cell growth in vivo has only been obtained recently. Mice with mutations in the PI 3-kinase catalytic p110a isoform that block its ability to interact with RAS are highly resistant to endogenous KRAS oncogene induced lung tumourigenesis and HRAS oncogene induced skin carcinogenesis. Cells from these mice show proliferative defects and selective disruption of signalling from certain growth factors to PI 3-kinase, while the mice also display delayed development of the lymphatic vasculature. The interaction of RAS with p110a is thus required in vivo for some normal growth factor signalling and also for RAS-driven tumour formation. RAS family members were among the first oncogenes identified over 40 years ago. In the late 1960s, the rat-derived Harvey and Kirsten murine sarcoma retroviruses were discovered and subsequently shown to promote cancer formation through related oncogenes, termed RAS (from rat sarcoma virus). The central role of RAS proteins in human cancer is highlighted by the large number of tumours in which they are activated by mutation: approximately 20% of human cancers carry a mutation in RAS proteins. Because of the complex signalling network in which RAS operates, with multiple activators and effectors, each with a different pattern of tissue-specific expression and a distinct set of intracellular functions, one of the critical issues concerns the specific role of each effector in RAS-driven oncogenesis. In this chapter, we summarize current knowledge about how RAS regulates one of its best-known effectors, phosphoinositide 3-kinase (PI3K).
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Affiliation(s)
- Esther Castellano
- Signal Transduction Laboratory, Cancer Research UK London Research Institute, London, WC2A 3PX, UK
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Lau KS, Haigis KM. Non-redundancy within the RAS oncogene family: insights into mutational disparities in cancer. Mol Cells 2009; 28:315-20. [PMID: 19812895 PMCID: PMC3976423 DOI: 10.1007/s10059-009-0143-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 09/11/2009] [Indexed: 12/11/2022] Open
Abstract
The RAS family of oncoproteins has been studied extensively for almost three decades. While we know that activation of RAS represents a key feature of malignant transformation for many cancers, we are only now beginning to understand the complex underpinnings of RAS biology. Here, we will discuss emerging cancer genome sequencing data in the context of what is currently known about RAS function. Taken together, retrospective studies of primary human tissues and prospective studies of experimental models support the notion that the variable mutation frequencies exhibited by the RAS oncogenes reflect unique functions of the RAS oncoproteins.
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Affiliation(s)
- Ken S. Lau
- Molecular Pathology Unit and Center for Cancer Research, Massachusetts General Hospital and Department of Pathology, Harvard Medical School, USA
| | - Kevin M. Haigis
- Molecular Pathology Unit and Center for Cancer Research, Massachusetts General Hospital and Department of Pathology, Harvard Medical School, USA
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30
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Bertrand S, Campo-Paysaa F, Camasses A, García-Fernàndez J, Escrivà H. Actors of the tyrosine kinase receptor downstream signaling pathways in amphioxus. Evol Dev 2009; 11:13-26. [PMID: 19196330 DOI: 10.1111/j.1525-142x.2008.00299.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
One of the major goals of evo-developmentalists is to understand how the genetic mechanisms controlling embryonic development have evolved to create the current diversity of bodyplans that we encounter in the animal kingdom. Tyrosine kinase receptors (RTKs) are transmembrane receptors present in all metazoans known to control several developmental processes. They act via the activation of various cytoplasmic signaling cascades, including the mitogen-activated protein kinase (MAPK), the PI3K/Akt, and the phospholipase C-gamma (PLCgamma)/protein kinase C (PKC) pathways. In order to address the evolution of these three pathways and their involvement during embryogenesis in chordates, we took advantage of the complete genome sequencing of a key evolutionarily positioned species, the cephalochordate amphioxus, and searched for the complete gene set of the three signaling pathways. We found that the amphioxus genome contains all of the most important modules of the RTK-activated cascades, and looked at the embryonic expression of two genes selected from each cascade. Our data suggest that although the PI3K/Akt pathway may have ubiquitous functions, the MAPK and the PLCgamma/PKC cascades may play specific roles in amphioxus development. Together with data known in vertebrates, the expression pattern of PKC in amphioxus suggests that the PLCgamma/PKC cascade was implicated in neural development in the ancestor of all chordates.
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Affiliation(s)
- Stéphanie Bertrand
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, edifici annex, planta, 08028 Barcelona, Spain
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Rhee JS, Lee YM, Raisuddin S, Lee JS. Expression of R-ras oncogenes in the hermaphroditic fish Kryptolebias marmoratus, exposed to endocrine disrupting chemicals. Comp Biochem Physiol C Toxicol Pharmacol 2009; 149:433-9. [PMID: 19000778 DOI: 10.1016/j.cbpc.2008.10.102] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 10/06/2008] [Accepted: 10/07/2008] [Indexed: 12/25/2022]
Abstract
The hermaphroditic fish Krytolebias marmoratus is a potential fish model for study of tumour development. Recently, sequences and expression of some oncogenes and tumor suppressor gene have been studied in K. marmoratus. To get a better understanding of oncogene expression at different development stage, and in different tissues three R-ras genes were cloned and fully sequenced. Expression of these R-ras genes (R-ras1, R-ras2, R-ras3) was also studied in fish exposed to endocrine-disrupting chemicals (EDCs). Liver showed the highest level of expression compared to other tissues, even though each R-ras gene showed different expression patterns in tissues. Interestingly, in secondary male (ovary atresia stage), expression levels of three R-ras genes was lower compared to hermaphrodites. At different developmental stages, R-ras2 gene showed most pronounced expression at early embryogenesis but at stage 5 (hatchling stage) and juvenile stage, R-ras3 gene showed the highest expression. After the juvenile stage, R-ras1 gene was upregulated compared to other R-ras genes, which showed the highest expression at the hermaphroditic stage. When fish were exposed to 17-beta-estradiol (E2), a natural estrogen and tamoxifen, a nonsteroidal estrogen antagonist and three EDCs viz., 4-n-nonylphenol (NP), bisphenol A (BPA), and 4-tert-octylphenol (OP), all the three R-ras genes were induced, except in the fish exposed to tamoxifen. These results suggest that EDCs modulate the expression of R-ras genes and thus affect subsequent signal transduction and tumor development.
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Affiliation(s)
- Jae-Sung Rhee
- Department of Molecular and Environmental Bioscience, Graduate School, Hanyang University, Seoul 133-791, South Korea
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32
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Schuhmacher AJ, Guerra C, Sauzeau V, Cañamero M, Bustelo XR, Barbacid M. A mouse model for Costello syndrome reveals an Ang II-mediated hypertensive condition. J Clin Invest 2008; 118:2169-79. [PMID: 18483625 DOI: 10.1172/jci34385] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Accepted: 03/26/2008] [Indexed: 01/23/2023] Open
Abstract
Germline activation of H-RAS oncogenes is the primary cause of Costello syndrome (CS), a neuro-cardio-facio-cutaneous developmental syndrome. Here we describe the generation of a mouse model of CS by introduction of an oncogenic Gly12Val mutation in the mouse H-Ras locus using homologous recombination in ES cells. Germline expression of the endogenous H-RasG12V oncogene, even in homozygosis, resulted in hyperplasia of the mammary gland. However, development of tumors in these mice was rare. H-RasG12V mutant mice closely phenocopied some of the abnormalities observed in patients with CS, including facial dysmorphia and cardiomyopathies. These mice also displayed alterations in the homeostasis of the cardiovascular system, including development of systemic hypertension, extensive vascular remodeling, and fibrosis in both the heart and the kidneys. This phenotype was age dependent and was a consequence of the abnormal upregulation of the renin-Ang II system. Treatment with captopril, an inhibitor of Ang II biosynthesis, prevented development of the hypertension condition, vascular remodeling, and heart and kidney fibrosis. In addition, it partially alleviated the observed cardiomyopathies. These mice should help in elucidating the etiology of CS symptoms, identifying additional defects, and evaluating potential therapeutic strategies.
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Affiliation(s)
- Alberto J Schuhmacher
- Molecular Oncology Programme, Centro Nacional de Investigaciones Oncológicas, Madrid, Spain
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33
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Abstract
Extensive research on the Ras proteins and their functions in cell physiology over the past 30 years has led to numerous insights that have revealed the involvement of Ras not only in tumorigenesis but also in many developmental disorders. Despite great strides in our understanding of the molecular and cellular mechanisms of action of the Ras proteins, the expanding roster of their downstream effectors and the complexity of the signalling cascades that they regulate indicate that much remains to be learnt.
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Affiliation(s)
- Antoine E. Karnoub
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Robert A. Weinberg
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
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Lee YM, Raisuddin S, Rhee JS, Ki JS, Kim IC, Lee JS. Modulatory effect of environmental endocrine disruptors on N-ras oncogene expression in the hermaphroditic fish, Kryptolebias marmoratus. Comp Biochem Physiol C Toxicol Pharmacol 2008; 147:299-305. [PMID: 18248853 DOI: 10.1016/j.cbpc.2007.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 11/24/2007] [Accepted: 11/26/2007] [Indexed: 12/27/2022]
Abstract
Kryptolebias marmoratus is the only known internally self-fertilizing vertebrate. It shows high susceptibility to many chemical carcinogens and has been proposed as a potential cancer model species alternative to mammals. Since use of this fish species is expected to rise in cancer research, regulation of oncogenes from K. marmoratus needs proper understanding. We cloned and deduced full-length sequence of cDNA of N-ras oncogene from K. marmoratus. Study of expression profile of N-ras by using quantitative real-time RT-PCR revealed that brain had the highest level of expression compared to other tissues. Some embryonic stages showed more N-ras expression than juveniles and adults. Exposure to two environmental endocrine disrupting chemicals (EDCs), bisphenol A (BPA) and 4-nonylphenyl (NP) caused up-regulation of N-ras in gonad, intestine and liver of hermaphrodite K. marmoratus. It is suggested that K. marmoratus may be a suitable model species for oncogene expression studies. The observed EDC-induced expression of N-ras supports the assumption that EDC exposure may predispose the host to the risk of environmental carcinogenesis.
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Affiliation(s)
- Young-Mi Lee
- Department of Chemistry and the National Research Lab of Marine Molecular and Environmental Bioscience, College of Natural Sciences, Hanyang University, Seoul 133-791, South Korea
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Nakamura K, Ichise H, Nakao K, Hatta T, Otani H, Sakagami H, Kondo H, Katsuki M. Partial functional overlap of the three ras genes in mouse embryonic development. Oncogene 2007; 27:2961-8. [PMID: 18059342 DOI: 10.1038/sj.onc.1210956] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In mammals, three ras genes, H-ras, N-ras and K-ras, encode homologous but distinct 21-kDa Ras proteins. We examined the in vivo functional relationship of the three ras genes in mouse embryonic development by investigating the phenotypes of mice deficient in one or multiple ras genes. H-ras-/- mice and N-ras-/- mice as well as a substantial proportion of H-ras-/-/N-ras-/- mice expressing only the K-ras gene were viable, while K-ras-/- mice were embryonically lethal, as have been reported previously. N-ras-/-/K-ras+/- mice died neonatally, while H-ras-/-/K-ras-/- embryos died much earlier than K-ras homozygous mutant fetuses. To further investigate the functional relationship of the ras genes in embryonic development, we introduced a human H-ras transgene into single or multiple ras mutant mice and found that the transgene rescued mice, including triple ras mutants, from embryonic lethality in association with correction of thin ventricular walls of the heart in null K-ras mutant mice. In situ hybridization revealed that the expression of the H-ras transgene on embryonic day E13.5 and E15.5 was more intense in major organs, including the heart, than those of endogenous ras genes. We therefore conclude that the functions of the ras genes are partially overlapping in mouse embryonic development.
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Affiliation(s)
- K Nakamura
- Mouse Genome Technology Laboratory, Mitsubishi Kagaku Institute of Life Sciences, Machida, Tokyo, Japan
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36
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Ruocco A, Santillo M, Cicale M, Serù R, Cuda G, Anrather J, Iadecola C, Postiglione A, Avvedimento EV, Paternò R. Farnesyl transferase inhibitors induce neuroprotection by inhibiting Ha-Ras signalling pathway. Eur J Neurosci 2007; 26:3261-6. [PMID: 18005061 DOI: 10.1111/j.1460-9568.2007.05935.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In previous studies we found that the GTPase p21 Harvey-Ras (Ha-Ras) stimulates the production of reactive oxygen species and induces apoptosis by oxidative stress; this effect was reversed by farnesyl transferase inhibitors (FTIs). In this study we investigated whether FTIs reduce rat brain damage induced by an excitotoxic stimulus, and the signalling pathway(s) underlying the neuroprotection by FTIs. In brain tissue, protein levels of Ha-Ras and farnesylation inhibition were assayed by Western blot, and superoxide production was measured by hydroethidine. The excitotoxic lesion was induced by intrastriatal injection of N-methyl-d-aspartate (NMDA). The survival of mouse neuronal cortical cells was assessed by 3-(4,5 dimethylthialzol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). In brain tissue, NMDA increased the protein levels of Ha-Ras, FTIs caused the accumulation of non-prenylated inactive Ras in the cytosolic fraction, and significantly reduced superoxide production and necrotic volume after excitotoxicity. FTIs increased the viability of mouse neuronal cortical cells following oxidative stress. In conclusion, FTIs inhibited Ha-Ras, decreased oxidative stress and reduced necrotic volume by partly acting on neuronal cells. Thus, Ha-Ras inhibition plays a role in the pathology of neuroprotection, suggesting a potential role of FTIs in the treatment of cerebrovascular diseases.
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Affiliation(s)
- Antonio Ruocco
- Department of Clinical and Experimental Medicine, Federico II University, Naples, Italy
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37
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Khalaf WF, Yang FC, Chen S, White H, Bessler W, Ingram DA, Clapp DW. K-ras is critical for modulating multiple c-kit-mediated cellular functions in wild-type and Nf1+/- mast cells. THE JOURNAL OF IMMUNOLOGY 2007; 178:2527-34. [PMID: 17277161 DOI: 10.4049/jimmunol.178.4.2527] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
p21(ras) (Ras) proteins and GTPase-activating proteins (GAPs) tightly modulate extracellular growth factor signals and control multiple cellular functions. The specific function of each Ras isoform (H, N, and K) in regulating distinct effector pathways, and the role of each GAP in negatively modulating the activity of each Ras isoform in myeloid cells and, particularly, mast cells is incompletely understood. In this study, we use murine models of K-ras- and Nf1-deficient mice to examine the role of K-ras in modulating mast cell functions and to identify the role of neurofibromin as a GAP for K-ras in this lineage. We find that K-ras is required for c-kit-mediated mast cell proliferation, survival, migration, and degranulation in vitro and in vivo. Furthermore, the hyperactivation of these cellular functions in Nf1(+/-) mast cells is decreased in a K-ras gene dose-dependent fashion in cells containing mutations in both loci. These findings identify K-ras as a key effector in multiple mast cell functions and identify neurofibromin as a GAP for K-ras in mast cells.
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Affiliation(s)
- Waleed F Khalaf
- Department Microbiology & Immunology, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Rajalingam K, Schreck R, Rapp UR, Albert S. Ras oncogenes and their downstream targets. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:1177-95. [PMID: 17428555 DOI: 10.1016/j.bbamcr.2007.01.012] [Citation(s) in RCA: 303] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 01/17/2007] [Accepted: 01/19/2007] [Indexed: 12/30/2022]
Abstract
RAS proteins are small GTPases, which serve as master regulators of a myriad of signaling cascades involved in highly diverse cellular processes. RAS oncogenes have been originally discovered as retroviral oncogenes, and ever since constitutively activating RAS mutations have been identified in human tumors, they are in the focus of intense research. In this review, we summarize the biochemical properties of RAS proteins, trace down the evolution of RAS signaling and present an overview of the spatio-temporal activation of major RAS isoforms. We further discuss RAS effector pathways, their role in normal and transformed cell physiology and summarize ongoing attempts to interfere with aberrant RAS signaling. Finally, we comment on the role of micro RNAs in modulating RAS expression, contribution of RAS to stem cell function and on high-throughput analyses of RAS signaling networks.
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Affiliation(s)
- Krishnaraj Rajalingam
- University of Würzburg, Institut für Medizinische Strahlenkunde und Zellforschung, Versbacherstr. 5, D-97078 Würzburg, Germany
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Castellano E, De Las Rivas J, Guerrero C, Santos E. Transcriptional networks of knockout cell lines identify functional specificities of H-Ras and N-Ras: significant involvement of N-Ras in biotic and defense responses. Oncogene 2006; 26:917-33. [PMID: 16909116 DOI: 10.1038/sj.onc.1209845] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We characterized differential gene expression profiles of fibroblast cell lines harboring single or double-homozygous null mutations in H-ras and N-ras. Whereas the expression level of the individual H-, N- and K-ras genes appeared unaffected by the presence or absence of the other ras loci, significant differences were observed between the expression profiles of cells missing N-ras and/or H-ras. Absence of N-ras produced much stronger effects than absence of H-ras over the profile of the cellular transcriptome. N-ras(-/-) and H-ras(-/-) fibroblasts displayed rather antagonistic expression profiles and the transcriptome of H-ras(-/-) cells was significantly closer to that of wild-type fibroblasts than to that of N-ras(-/-) cells. Classifying all differentially expressed genes into functional categories suggested specific roles for H-Ras and N-Ras. It was particularly striking in N-ras(-/-) cells the upregulation of a remarkable number of immunity-related genes, as well as of several loci involved in apoptosis. Reverse-phase protein array assays demonstrated in the same N-ras(-/-) cells the overexpression and nuclear migration of tyrosine phosphorylated signal transducer and activator of transcription 1 (Stat1) which was concomitant with transcriptional activation mediated by interferon-stimulated response elements. Significantly enhanced numbers of apoptotic cells were also detected in cultures of N-ras(-/-) cells. Our data support the notion that different Ras isoforms play functionally distinct cellular roles and indicate that N-Ras is significantly involved in immune modulation/host defense and apoptotic responses.
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Affiliation(s)
- E Castellano
- Instituto de Biología Molecular y Celular del Cáncer, Centro de Investigación del Cáncer (CSIC-USAL), University of Salamanca, Salamanca, Spain
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40
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Griffith LC, Budnik V. Plasticity and second messengers during synapse development. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2006; 75:237-65. [PMID: 17137931 PMCID: PMC4664443 DOI: 10.1016/s0074-7742(06)75011-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Effective function of the locomotor system in the Drosophila larva requires a continuous adjustment of synaptic architecture and neurotransmission at the neuromuscular junction (NMJ). This feature has made the larval NMJ a favorite model to study the genetic and molecular mechanisms underlying synapse plasticity. This chapter will review experimental strategies used to study plasticity at the NMJ, the cellular parameters affected during plastic changes, and many of the known molecules involved in plastic changes. In addition, signal transduction pathways activated during plasticity will be discussed.
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Affiliation(s)
- Leslie C. Griffith
- Dept of Biology and National Center for Behavioral Genomics, Brandeis University, 415 South St., Waltham, MA, 02454, USA
- Corresponding Author: phone: 781 736 3125, FAX: 781 736 3107,
| | - Vivian Budnik
- Department of Neurobiology, University of Massachusetts Medical School, Aaron Lazare Medical Research Building, 364 Plantation Street Worcester, MA 01605-2324, USA
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Suvarna N, Borgland SL, Wang J, Phamluong K, Auberson YP, Bonci A, Ron D. Ethanol Alters Trafficking and Functional N-Methyl-D-aspartate Receptor NR2 Subunit Ratio via H-Ras. J Biol Chem 2005; 280:31450-9. [PMID: 16009711 DOI: 10.1074/jbc.m504120200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The N-methyl-D-aspartate receptor (NMDAR) plays a critical role in synaptic plasticity and is one of the main targets for alcohol (ethanol) in the brain. Trafficking of the NMDAR is emerging as a key regulatory mechanism that underlies channel activity and synaptic plasticity. Here we show that exposure of hippocampal neurons to ethanol increases the internalization of the NR2A but not NR2B subunit of the NMDAR via the endocytic pathway. We further observed that ethanol exposure results in NR2A endocytosis through the activation of H-Ras and the inhibition of the tyrosine kinase Src. Importantly, ethanol treatment alters functional subunit composition from NR2A/NR2B- to mainly NR2B-containing NMDARs. Our results suggest that addictive drugs such as ethanol alter NMDAR trafficking and subunit composition. This may be an important mechanism by which ethanol exerts its effects on NMDARs to produce alcohol-induced aberrant plasticity.
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Affiliation(s)
- Neesha Suvarna
- Ernest Gallo Research Center, Emeryville, California 94608, USA
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Scher JU, Pillinger MH. 15d-PGJ2: the anti-inflammatory prostaglandin? Clin Immunol 2005; 114:100-9. [PMID: 15639643 DOI: 10.1016/j.clim.2004.09.008] [Citation(s) in RCA: 251] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2004] [Accepted: 09/23/2004] [Indexed: 01/22/2023]
Abstract
15-Deoxy-Delta-12,14-prostaglandin J2 (15d-PGJ2) is the most recently discovered prostaglandin. This cyclopentanone, the dehydration end product of PGD2, differs from other prostaglandins in several respects. There is no specific prostaglandin synthase (PGS) leading to 15d-PGJ2 production and no specific 15d-PGJ2 receptor has been identified to date. Instead, 15d-PGJ2 has been shown to act via PGD2 receptors (DP1 and DP2) and through interaction with intracellular targets. In particular, 15d-PGJ2 is recognized as the endogenous ligand for the intranuclear receptor PPARgamma. This property is responsible for many of the 15d-PGJ2 anti-inflammatory functions. In this review, we summarize the current understanding of 15d-PGJ2 synthesis, biology and main effects both in molecular physiology and pathological states.
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Affiliation(s)
- Jose U Scher
- The Division of Rheumatology, New York University School of Medicine, New York, NY 10003, USA
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Wainwright MS, Brennan LA, Dizon ML, Black SM. p21ras activation following hypoxia-ischemia in the newborn rat brain is dependent on nitric oxide synthase activity but p21ras does not contribute to neurologic injury. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2003; 146:79-85. [PMID: 14643014 DOI: 10.1016/j.devbrainres.2003.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Hypoxia-ischemia (HI) in the perinatal period is associated with significant infant mortality and neurologic morbidity. Increase in the activity of nitric oxide synthase (NOS) and increased release of nitric oxide (NO) are cardinal events in the pathophysiology of stroke and perinatal asphyxia. Cell culture studies suggest that the GTP-binding protein p21ras (Ras) is activated by NO in an NMDA-receptor-dependent pathway. These findings imply that Ras may be activated in vivo by NO released in response to glutamate stimulation during HI. The contribution of downstream Ras activation to neurologic injury after perinatal HI is unknown. We used a postnatal day 7 rat model of perinatal hypoxia-ischemia to determine the response of Ras to HI, the role of NO in Ras activation and the effect of Ras inhibition on neurologic injury in vivo. Ras is activated in both hippocampus and cortex within 2 h after HI. This increase is prevented by treatment with the NOS inhibitor, aminoguanidine (AG) and by a farnesyl/protein transferase inhibitor, manumycin (MAN). Inhibition of NOS, but not Ras, significantly reduces neurologic injury after a 7-day recovery period. This data suggests that Ras is activated during the initiation of the cellular response to HI in both hippocampus and cortex and that this activation is NO-dependent. Ras does not, however, contribute to the pathophysiologic NO-dependent mechanisms of neurologic injury in this model.
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Affiliation(s)
- Mark S Wainwright
- Department of Pediatrics, Division of Neurology, Northwestern University, Chicago, IL, USA
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Liu Z, Kullman SW, Bencic DC, Torten M, Hinton DE. ras oncogene mutations in diethylnitrosamine-induced hepatic tumors in medaka (Oryzias latipes), a teleost fish. Mutat Res 2003; 539:43-53. [PMID: 12948813 DOI: 10.1016/s1383-5718(03)00133-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Medaka fish are an established non-mammalian research model for the study of liver carcinogenesis and exposure to environmental pollutants. Studies have emphasized the development of hepatic neoplasms in medaka following exposure to model carcinogens. To date however, little information is known regarding the mechanisms underlying initiation of hepatic tumors in this species. The aim of this study was to relate our understanding of diethylnitrosamine (DEN)-induced tumor formation to ras gene activation in hepatic neoplasms of exposed medaka. Initial studies were conducted to identify medaka ras exons 1 and 2 by reverse transcriptase polymerase chain reaction (RT-PCR). Amplification of ras exons 1 and 2 from untreated medaka liver resulted in the identification of three polymorphic ras sequence variants exhibiting a high degree of homology to other teleost and mammalian ras genes. Exposure of medaka to 159 ppm of DEN resulted in a wide range of hepatic neoplasms including: hepatocellular adenomas, hepatocellular carcinomas, cholangiomas, and mixed hepatocholangiocellular carcinomas. Individual liver tumors were examined for oncogenically activating ras mutations by probing genomic DNA with probes specific for activating point mutations or by direct cloning and sequencing of ras transcripts using RT-PCR. Using allele-specific oligonucleotide (ASO) analysis, a single point mutation was detected in codon 12 position two in 8/25 (32%) tumors examined. Mutated ras alleles were additionally detected in 12 of 39 (30%) medaka liver tumors by sequence analysis. Ten of the 12 mutations identified contained a single point mutation at codon 12 resulting in a Gly to Asp amino acid substitution. Two unique mutations were identified at codon 16 resulting in either Lys to Asn or Lys to Thr amino acid substitutions. Our results show that ras mutations are induced by DEN and are present in over 30% of the fish that developed tumors. A ras mutation incidence of 30% is similar to that reported in mammalian species exposed to DEN. While mutations at codon 12 have previously been reported, the present study is the first in vivo report of ras point mutations at codon 16.
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Affiliation(s)
- Zi Liu
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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Guerra C, Mijimolle N, Dhawahir A, Dubus P, Barradas M, Serrano M, Campuzano V, Barbacid M. Tumor induction by an endogenous K-ras oncogene is highly dependent on cellular context. Cancer Cell 2003; 4:111-20. [PMID: 12957286 DOI: 10.1016/s1535-6108(03)00191-0] [Citation(s) in RCA: 447] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have targeted a K-ras allele in mouse embryonic stem (ES) cells to express a K-Ras(V12) oncoprotein along with a marker protein (beta-geo) from a single bicistronic transcript. Expression of this oncogenic allele requires removal of a knocked in STOP transcriptional cassette by Cre recombinase. Primary mouse embryonic fibroblasts expressing this K-ras(V12) allele do not undergo proliferative senescence and proliferate as immortal cells. In mice, expression of K-ras(V12) throughout the body fails to induce unscheduled proliferation or other growth abnormalities for up to eight months. Only a percentage of K-ras(V12)-expressing lung bronchiolo-alveolar cells undergo malignant transformation leading to the formation of multiple adenomas and adenocarcinomas. These results indicate that neoplastic growth induced by an endogenous K-ras oncogene depends upon cellular context.
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Affiliation(s)
- Carmen Guerra
- Molecular Oncology Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), Melchor Fernández Almagro 3, 28029, Madrid, Spain
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Vikis H, Guan KL. Regulation of the Ras-MAPK pathway at the level of Ras and Raf. GENETIC ENGINEERING 2003; 24:49-66. [PMID: 12416300 DOI: 10.1007/978-1-4615-0721-5_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- Haris Vikis
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
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Roy D, Calaf G, Hei TK. Allelic imbalance at 11p15.5-15.4 correlated with c-Ha-ras mutation during radiation-induced neoplastic transformation of human breast epithelial cells. Int J Cancer 2003; 103:730-7. [PMID: 12516091 DOI: 10.1002/ijc.10895] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Breast cancer is the most frequent malignancy in women throughout much of the developed world and is associated with a multistage process involving a number of genetic mutations and their corresponding cellular phenotypic alterations. It has already been shown that neoplastic transformation of a spontaneously immortalized human breast epithelial (MCF-10F) cell line by radiation, in combination with estrogen, represents a successful model in studying the molecular and biological alterations that may contribute to the tumorigenic process. In the present study, the incidence of allelic alterations (microsatellite instability/loss of heterozygosity) on chromosome 11 in different radiation-induced primary and secondary tumorigenic cell lines, relative to the control MCF-10F cells was investigated. We identified 3 regions of the chromosome 11 (11p15-p15.5, 11q13 and 11q23) that showed high incidence of LOH among these tumor cell lines and suggested a potential role for these chromosomal regions in breast carcinogenesis. Among them, locus 11p15.5, where c-Ha-ras oncogene is located, had incidence of allelic imbalance between 25-40%. Furthermore, direct sequencing analysis of codons 12 and 61 of the c-Ha-ras oncogene identified various point mutations. These data highlight the importance of chromosome 11 in radiation induced malignant transformation of human breast epithelial cells and suggest the usefulness of the model in uncovering specific derangements during breast cancer progression.
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Affiliation(s)
- Debasish Roy
- Center for Radiological Research, Vanderbilt Clinic, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA.
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Matallanas D, Arozarena I, Berciano MT, Aaronson DS, Pellicer A, Lafarga M, Crespo P. Differences on the inhibitory specificities of H-Ras, K-Ras, and N-Ras (N17) dominant negative mutants are related to their membrane microlocalization. J Biol Chem 2003; 278:4572-81. [PMID: 12458225 DOI: 10.1074/jbc.m209807200] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ras GTPases include the isoforms H-Ras, K-Ras, and N-Ras. Despite their great biochemical and biological similarities, evidence is mounting suggesting that Ras proteins may not be functionally redundant. A widespread strategy for studying small GTPases is the utilization of dominant inhibitory mutants that specifically block the activation of their respective wild-type proteins. As such, H-Ras N17 has proved to be extremely valuable as a tool to probe Ras functions. However, a comparative study on the inhibitory specificities of H-, K-, and N-Ras N17 mutants has not been approached thus far. Herein, we demonstrate that H-, K-, and N-Ras N17 mutants exhibit markedly distinct inhibitory effects toward H-, K-, and N-Ras. H-Ras N17 can effectively inhibit the activation of all three isoforms. K-Ras N17 completely blocks the activation of K-Ras and is only slightly inhibitory on H-Ras. N-Ras N17 can mainly inhibit N-Ras activation. In light of the recent data on the compartmentalization of H-Ras and K-Ras in the plasma membrane, here we present for the first time a description of N-Ras cellular microlocalization. Overall, our results on Ras N17 mutants specificities exhibit a marked correlation with the localization of the Ras isoforms to distinct membrane microdomains.
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Affiliation(s)
- David Matallanas
- Departamentos de Biología Molecular, Universidad de Cantabria, Santander 39011, Spain
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Sugiyama T, Osaka M, Koami K, Maeda S, Ueda N. 7,12-DMBA-induced rat leukemia: a review with insights into future research. Leuk Res 2002; 26:1053-68. [PMID: 12443876 DOI: 10.1016/s0145-2126(02)00045-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
7,12-Dimethylbenz[a]anthracene (DMBA) elicits leukemia in Long-Evans rats (LE). This leukemia is mostly erythroblastic and 30% of leukemias have total and partial trisomy of #2 chromosome and the rest have diploid karyotype. The common duplication site is in 2q26-q34 and N-ras gene is located in 2q34. 7,8,12-Trimethylbenz[a]anthracene (TMBA) also induces similar leukemias. These leukemias reveal a highly specific mutation of N-ras gene as in human leukemias. N-ras mutation is induced 48h after DMBA treatment. Wild type N-ras allele is frequently lost in diploid leukemias but not in trisomy type. Therefore, a gene dosage problem related to the mutant N-ras gene is involved in development of leukemia. Some secondary genetic rearrangements involving abl and H-ras are also observed in cultured leukemia cells. DMBA-induced chromosome aberrations as well as leukemia are enhanced by erythropoietin and blocked by Sudan III given prior to DMBA treatment. This leukemia will provide an important tool for chemical carcinogenesis and leukemia studies.
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Woods SA, Marmor E, Feldkamp M, Lau N, Apicelli AJ, Boss G, Gutmann DH, Guha A. Aberrant G protein signaling in nervous system tumors. J Neurosurg 2002; 97:627-42. [PMID: 12296648 DOI: 10.3171/jns.2002.97.3.0627] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Object. Guanosine triphosphate (GTP)—binding proteins, also known as G proteins, play important roles in the regulation of cell growth and differentiation by transmitting intracellular signals from cell surface receptors. In this paper, the authors review G protein signaling in general and its aberrations in four human nervous system tumors.
Methods. In the nervous system, four tumor types have been associated with aberrant G protein signaling. The first tumor type includes astrocytomas, which have increased levels of the activated form of the small G protein, p21-ras, without primary oncogenic p21-ras mutations. The likely source for increased p21-ras activity in sporadically occurring astrocytomas is overexpressed or constitutively activated growth factor receptors, whereas in neurofibromatosis Type 1 (NF1)—associated astrocytomas, the source is a loss of expression of neurofibromin, a major inactivator of p21-ras (ras—GTPase activating protein [GAP]). The second type of tumor associated with aberrant G protein signaling includes sporadic and NF1-associated neurofibromas and malignant peripheral nerve sheath tumors, which also have increased p21-ras activity due to a loss of neurofibromin expression. The third tumor type includes subependymal giant cell astrocytomas as part of the tuberous sclerosis complex (TSC). These tumors display a loss of tuberin expression due to germline mutations in the TSC2 gene. Tuberin functions as an inactivator of the small G protein rap1B (rap1-GAP) and, hence, loss of its expression could lead to increased rap1B activity. In addition to TSC-associated tumors, the authors demonstrate that the majority of sporadically occurring astrocytomas display either loss of tuberin or overexpression of rap1B. This suggests that increased rap1B activity, which can augment p21-ras—mediated signals, also contributes to G protein—mediated aberrant signaling in sporadically occurring astrocytomas. The fourth tumor type includes a significant subset of pituitary adenomas that show constitutive activation of the Gα subunit of the large heterotrimeric Gs protein, which is involved in hormone receptor signaling. The net result of this aberrant activation is increased cyclic adenosine monophosphate and mitogenic tumor-promoting signals.
Conclusions. The authors' review of G protein signaling and aberrations in this process is made with the long-term view that increased understanding of relevant signaling pathways will eventually lead to novel biological targeted therapies against these tumors.
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Affiliation(s)
- Stacey A Woods
- Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
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