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Zhang JZ, Ong SE, Baker D, Maly DJ. Single-cell sensor analyses reveal signaling programs enabling Ras-G12C drug resistance. Nat Chem Biol 2024:10.1038/s41589-024-01684-4. [PMID: 39103633 DOI: 10.1038/s41589-024-01684-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 06/23/2024] [Indexed: 08/07/2024]
Abstract
Clinical resistance to rat sarcoma virus (Ras)-G12C inhibitors is a challenge. A subpopulation of cancer cells has been shown to undergo genomic and transcriptional alterations to facilitate drug resistance but the immediate adaptive effects on Ras signaling in response to these drugs at the single-cell level is not well understood. Here, we used Ras biosensors to profile the activity and signaling environment of endogenous Ras at the single-cell level. We found that a subpopulation of KRas-G12C cells treated with Ras-G12C-guanosine-diphosphate inhibitors underwent adaptive signaling and metabolic changes driven by wild-type Ras at the Golgi and mutant KRas at the mitochondria, respectively. Our Ras biosensors identified major vault protein as a mediator of Ras activation through its scaffolding of Ras signaling pathway components and metabolite channels. Overall, methods including ours that facilitate direct analysis on the single-cell level can report the adaptations that subpopulations of cells adopt in response to cancer therapies, thus providing insight into drug resistance.
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Affiliation(s)
- Jason Z Zhang
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
- Institute for Protein Design, University of Washington, Seattle, WA, USA.
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA.
| | - Shao-En Ong
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Dustin J Maly
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Department of Chemistry, University of Washington, Seattle, WA, USA
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2
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Zhang JZ, Ong SE, Baker D, Maly DJ. Single-cell signaling analysis reveals that Major Vault Protein facilitates RasG12C inhibitor resistance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.02.560617. [PMID: 37873412 PMCID: PMC10592919 DOI: 10.1101/2023.10.02.560617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Recently developed covalent inhibitors for RasG12C provide the first pharmacological tools to target mutant Ras-driven cancers. However, the rapid development of resistance to current clinical Ras G12C inhibitors is common. Presumably, a subpopulation of RasG12C-expressing cells adapt their signaling to evade these inhibitors and the mechanisms for this phenomenon are unclear due to the lack of tools that can measure signaling with single-cell resolution. Here, we utilized recently developed Ras sensors to profile the environment of active Ras and to measure the activity of endogenous Ras in order to pair structure (Ras signalosome) to function (Ras activity), respectively, at a single-cell level. With this approach, we identified a subpopulation of KRasG12C cells treated with RasG12C-GDP inhibitors underwent oncogenic signaling and metabolic changes driven by WT Ras at the golgi and mutant Ras at the mitochondria, respectively. Our Ras sensors identified Major Vault Protein (MVP) as a mediator of Ras activation at both compartments by scaffolding Ras signaling pathway components and metabolite channels. We found that recently developed RasG12C-GTP inhibitors also led to MVP-mediated WT Ras signaling at the golgi, demonstrating that this a general mechanism RasG12C inhibitor resistance. Overall, single-cell analysis of structure-function relationships enabled the discovery of a RasG12C inhibitor-resistant subpopulation driven by MVP, providing insight into the complex and heterogenous rewiring occurring during drug resistance in cancer.
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Affiliation(s)
- Jason Z. Zhang
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States
- Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, United States
| | - Shao-En Ong
- Department of Pharmacology, University of Washington, Seattle, Washington 98195, United States
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States
- Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, United States
| | - Dustin J. Maly
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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3
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Nolan A, Raso C, Kolch W, von Kriegsheim A, Wynne K, Matallanas D. Proteomic Mapping of the Interactome of KRAS Mutants Identifies New Features of RAS Signalling Networks and the Mechanism of Action of Sotorasib. Cancers (Basel) 2023; 15:4141. [PMID: 37627169 PMCID: PMC10452836 DOI: 10.3390/cancers15164141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
RAS proteins are key regulators of cell signalling and control different cell functions including cell proliferation, differentiation, and cell death. Point mutations in the genes of this family are common, particularly in KRAS. These mutations were thought to cause the constitutive activation of KRAS, but recent findings showed that some mutants can cycle between active and inactive states. This observation, together with the development of covalent KRASG12C inhibitors, has led to the arrival of KRAS inhibitors in the clinic. However, most patients develop resistance to these targeted therapies, and we lack effective treatments for other KRAS mutants. To accelerate the development of RAS targeting therapies, we need to fully characterise the molecular mechanisms governing KRAS signalling networks and determine what differentiates the signalling downstream of the KRAS mutants. Here we have used affinity purification mass-spectrometry proteomics to characterise the interactome of KRAS wild-type and three KRAS mutants. Bioinformatic analysis associated with experimental validation allows us to map the signalling network mediated by the different KRAS proteins. Using this approach, we characterised how the interactome of KRAS wild-type and mutants is regulated by the clinically approved KRASG12C inhibitor Sotorasib. In addition, we identified novel crosstalks between KRAS and its effector pathways including the AKT and JAK-STAT signalling modules.
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Affiliation(s)
- Aoife Nolan
- Systems Biology Ireland, School of Medicine, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland; (A.N.); (C.R.); (W.K.); (A.v.K.); (K.W.)
| | - Cinzia Raso
- Systems Biology Ireland, School of Medicine, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland; (A.N.); (C.R.); (W.K.); (A.v.K.); (K.W.)
| | - Walter Kolch
- Systems Biology Ireland, School of Medicine, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland; (A.N.); (C.R.); (W.K.); (A.v.K.); (K.W.)
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, D04 V1W8 Dublin, Ireland
| | - Alex von Kriegsheim
- Systems Biology Ireland, School of Medicine, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland; (A.N.); (C.R.); (W.K.); (A.v.K.); (K.W.)
- Edinburgh Cancer Research UK Centre, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Kieran Wynne
- Systems Biology Ireland, School of Medicine, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland; (A.N.); (C.R.); (W.K.); (A.v.K.); (K.W.)
| | - David Matallanas
- Systems Biology Ireland, School of Medicine, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland; (A.N.); (C.R.); (W.K.); (A.v.K.); (K.W.)
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4
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Burge RA, Hobbs GA. Not all RAS mutations are equal: A detailed review of the functional diversity of RAS hot spot mutations. Adv Cancer Res 2022; 153:29-61. [PMID: 35101234 DOI: 10.1016/bs.acr.2021.07.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The RAS family of small GTPases are among the most frequently mutated oncogenes in human cancer. Approximately 20% of cancers harbor a RAS mutation, and >150 different missense mutations have been detected. Many of these mutations have mutant-specific biochemical defects that alter nucleotide binding and hydrolysis, effector interactions and cell signaling, prompting renewed efforts in the development of anti-RAS therapies, including the mutation-specific strategies. Previously viewed as undruggable, the recent FDA approval of a KRASG12C-selective inhibitor has offered real promise to the development of allele-specific RAS therapies. A broader understanding of the mutational consequences on RAS function must be developed to exploit additional allele-specific vulnerabilities. Approximately 94% of RAS mutations occur at one of three mutational "hot spots" at Gly12, Gly13 and Gln61. Further, the single-nucleotide substitutions represent >99% of these mutations. Within this scope, we discuss the mutational frequencies of RAS isoforms in cancer, mutant-specific effector interactions and biochemical properties. By limiting our analysis to this mutational subset, we simplify the analysis while only excluding a small percentage of total mutations. Combined, these data suggest that the presence or absence of select RAS mutations in human cancers can be linked to their biochemical properties. Continuing to examine the biochemical differences in each RAS-mutant protein will continue to provide additional breakthroughs in allele-specific therapeutic strategies.
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Affiliation(s)
- Rachel A Burge
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, United States
| | - G Aaron Hobbs
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, United States; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States.
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5
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RAS Dimers: The Novice Couple at the RAS-ERK Pathway Ball. Genes (Basel) 2021; 12:genes12101556. [PMID: 34680951 PMCID: PMC8535645 DOI: 10.3390/genes12101556] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 02/07/2023] Open
Abstract
Signals conveyed through the RAS-ERK pathway constitute a pivotal regulatory element in cancer-related cellular processes. Recently, RAS dimerization has been proposed as a key step in the relay of RAS signals, critically contributing to RAF activation. RAS clustering at plasma membrane microdomains and endomembranes facilitates RAS dimerization in response to stimulation, promoting RAF dimerization and subsequent activation. Remarkably, inhibiting RAS dimerization forestalls tumorigenesis in cellular and animal models. Thus, the pharmacological disruption of RAS dimers has emerged as an additional target for cancer researchers in the quest for a means to curtail aberrant RAS activity.
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Ramos-Kuri M, Meka SH, Salamanca-Buentello F, Hajjar RJ, Lipskaia L, Chemaly ER. Molecules linked to Ras signaling as therapeutic targets in cardiac pathologies. Biol Res 2021; 54:23. [PMID: 34344467 PMCID: PMC8330049 DOI: 10.1186/s40659-021-00342-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 06/26/2021] [Indexed: 12/11/2022] Open
Abstract
Abstract The Ras family of small Guanosine Triphosphate (GTP)-binding proteins (G proteins) represents one of the main components of intracellular signal transduction required for normal cardiac growth, but is also critically involved in the development of cardiac hypertrophy and heart failure. The present review provides an update on the role of the H-, K- and N-Ras genes and their related pathways in cardiac diseases. We focus on cardiac hypertrophy and heart failure, where Ras has been studied the most. We also review other cardiac diseases, like genetic disorders related to Ras. The scope of the review extends from fundamental concepts to therapeutic applications. Although the three Ras genes have a nearly identical primary structure, there are important functional differences between them: H-Ras mainly regulates cardiomyocyte size, whereas K-Ras regulates cardiomyocyte proliferation. N-Ras is the least studied in cardiac cells and is less associated to cardiac defects. Clinically, oncogenic H-Ras causes Costello syndrome and facio-cutaneous-skeletal syndromes with hypertrophic cardiomyopathy and arrhythmias. On the other hand, oncogenic K-Ras and alterations of other genes of the Ras-Mitogen-Activated Protein Kinase (MAPK) pathway, like Raf, cause Noonan syndrome and cardio-facio-cutaneous syndromes characterized by cardiac hypertrophy and septal defects. We further review the modulation by Ras of key signaling pathways in the cardiomyocyte, including: (i) the classical Ras-Raf-MAPK pathway, which leads to a more physiological form of cardiac hypertrophy; as well as other pathways associated with pathological cardiac hypertrophy, like (ii) The SAPK (stress activated protein kinase) pathways p38 and JNK; and (iii) The alternative pathway Raf-Calcineurin-Nuclear Factor of Activated T cells (NFAT). Genetic alterations of Ras isoforms or of genes in the Ras-MAPK pathway result in Ras-opathies, conditions frequently associated with cardiac hypertrophy or septal defects among other cardiac diseases. Several studies underline the potential role of H- and K-Ras as a hinge between physiological and pathological cardiac hypertrophy, and as potential therapeutic targets in cardiac hypertrophy and failure. Graphic abstract ![]()
The Ras (Rat Sarcoma) gene family is a group of small G proteins Ras is regulated by growth factors and neurohormones affecting cardiomyocyte growth and hypertrophy Ras directly affects cardiomyocyte physiological and pathological hypertrophy Genetic alterations of Ras and its pathways result in various cardiac phenotypes Ras and its pathway are differentially regulated in acquired heart disease Ras modulation is a promising therapeutic target in various cardiac conditions.
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Affiliation(s)
- Manuel Ramos-Kuri
- Instituto Nacional de Cancerología, Unidad de Investigación Biomédica en Cáncer, Secretarìa de Salud/Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, México.,Researcher of the Facultad de Bioética, Cátedra de Infertilidad, Universidad Anáhuac, Mexico City, México.,Centro de Investigación en Bioética y Genética, Querétaro, México
| | - Sri Harika Meka
- Division of Nephrology, Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Clinical and Translational Research Center, 875 Ellicott Street, Suite 8030B, Buffalo, NY, 14203, USA
| | - Fabio Salamanca-Buentello
- University of Toronto Institute of Medical Science, Medical Sciences Building, 1 King's College Circle, Room 2374, Toronto, ON, M5S 1A8, Canada
| | | | - Larissa Lipskaia
- INSERM U955 and Département de Physiologie, Hôpital Henri Mondor, FHU SENEC, AP-HP, and Université Paris-Est Créteil (UPEC), 94010, Créteil, France
| | - Elie R Chemaly
- Division of Nephrology, Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Clinical and Translational Research Center, 875 Ellicott Street, Suite 8030B, Buffalo, NY, 14203, USA.
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Busquets-Hernández C, Triola G. Palmitoylation as a Key Regulator of Ras Localization and Function. Front Mol Biosci 2021; 8:659861. [PMID: 33816563 PMCID: PMC8010249 DOI: 10.3389/fmolb.2021.659861] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 02/22/2021] [Indexed: 11/27/2022] Open
Abstract
Ras proteins require membrane association for proper function. This process is tightly regulated by reversible palmitoylation that controls not only the distribution over different subcellular compartments but also Ras compartmentalization within membrane subdomains. As a result, there is a growing interest in protein palmitoylation and the enzymes that control this process. In this minireview, we discuss how palmitoylation affects the localization and function of Ras proteins. A better understanding of the regulatory mechanism controlling protein lipidation is expected to provide new insights into the functional role of these modifications and may ultimately lead to the development of novel therapeutic approaches.
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Affiliation(s)
| | - Gemma Triola
- Department of Biological Chemistry, Laboratory of Chemical Biology, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
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8
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Kiel C, Matallanas D, Kolch W. The Ins and Outs of RAS Effector Complexes. Biomolecules 2021; 11:236. [PMID: 33562401 PMCID: PMC7915224 DOI: 10.3390/biom11020236] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 01/31/2021] [Accepted: 02/03/2021] [Indexed: 12/12/2022] Open
Abstract
RAS oncogenes are among the most commonly mutated proteins in human cancers. They regulate a wide range of effector pathways that control cell proliferation, survival, differentiation, migration and metabolic status. Including aberrations in these pathways, RAS-dependent signaling is altered in more than half of human cancers. Targeting mutant RAS proteins and their downstream oncogenic signaling pathways has been elusive. However, recent results comprising detailed molecular studies, large scale omics studies and computational modeling have painted a new and more comprehensive portrait of RAS signaling that helps us to understand the intricacies of RAS, how its physiological and pathophysiological functions are regulated, and how we can target them. Here, we review these efforts particularly trying to relate the detailed mechanistic studies with global functional studies. We highlight the importance of computational modeling and data integration to derive an actionable understanding of RAS signaling that will allow us to design new mechanism-based therapies for RAS mutated cancers.
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Affiliation(s)
- Christina Kiel
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin 4, Ireland; (C.K.); (D.M.)
- UCD Charles Institute of Dermatology, School of Medicine, University College Dublin, Dublin 4, Ireland
| | - David Matallanas
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin 4, Ireland; (C.K.); (D.M.)
| | - Walter Kolch
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin 4, Ireland; (C.K.); (D.M.)
- Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Dublin 4, Ireland
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9
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SV40 Polyomavirus Activates the Ras-MAPK Signaling Pathway for Vacuolization, Cell Death, and Virus Release. Viruses 2020; 12:v12101128. [PMID: 33028008 PMCID: PMC7650553 DOI: 10.3390/v12101128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 09/30/2020] [Accepted: 09/30/2020] [Indexed: 12/13/2022] Open
Abstract
Polyomaviruses are a family of small, non-enveloped DNA viruses that can cause severe disease in immunosuppressed individuals. Studies with SV40, a well-studied model polyomavirus, have revealed the role of host proteins in polyomavirus entry and trafficking to the nucleus, in viral transcription and DNA replication, and in cell transformation. In contrast, little is known about host factors or cellular signaling pathways involved in the late steps of productive infection leading to release of progeny polyomaviruses. We previously showed that cytoplasmic vacuolization, a characteristic late cytopathic effect of SV40 infection, depends on the specific interaction between the major viral capsid protein VP1 and its cell surface ganglioside receptor GM1. Here, we show that, late during infection, SV40 activates a signaling cascade in permissive monkey CV-1 cells involving Ras, Rac1, MKK4, and JNK to stimulate SV40-specific cytoplasmic vacuolization and subsequent cell lysis and virus release. Inhibition of individual components of this signaling pathway inhibits vacuolization, lysis, and virus release, even though high-level intracellular virus replication occurs. Identification of this pathway for SV40-induced vacuolization and virus release provides new insights into the late steps of non-enveloped virus infection.
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10
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García-Ibáñez Y, Riesco-Eizaguirre G, Santisteban P, Casar B, Crespo P. RAS Subcellular Localization Inversely Regulates Thyroid Tumor Growth and Dissemination. Cancers (Basel) 2020; 12:cancers12092588. [PMID: 32927904 PMCID: PMC7565207 DOI: 10.3390/cancers12092588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 12/11/2022] Open
Abstract
Simple Summary RAS mutations occur frequently in thyroid tumors, but the extent to which they are associated to tumor aggressiveness is still uncertain. HRAS proteins occupy different subcellular localizations, from which they regulate distinct biochemical processes. Herein, we demonstrate that the capacity of HRAS-transformed thyroid cells to extravasate and invade distant organs is orchestrated by HRAS subcellular localization, by a mechanism dependent on VEGF-B secretion. Interestingly, aggressiveness inversely correlates with tumor size. Moreover, we have identified the acyl protein thioesterase APT-1, a regulator of HRAS sublocalization, as a determinant of thyroid tumor growth versus dissemination. As such, alterations in APT-1 expression levels can dramatically affect the behavior of thyroid tumors. In this respect, APT-1 levels could serve as a biomarker that may help in the stratification of HRAS mutant thyroid tumors based on their aggressiveness. Abstract RAS mutations are the second most common genetic alteration in thyroid tumors. However, the extent to which they are associated with the most aggressive phenotypes is still controversial. Regarding their malignancy, the majority of RAS mutant tumors are classified as undetermined, which complicates their clinical management and can lead to undesired under- or overtreatment. Using the chick embryo spontaneous metastasis model, we herein demonstrate that the aggressiveness of HRAS-transformed thyroid cells, as determined by the ability to extravasate and metastasize at distant organs, is orchestrated by HRAS subcellular localization. Remarkably, aggressiveness inversely correlates with tumor size. In this respect, we also show that RAS site-specific capacity to regulate tumor growth and dissemination is dependent on VEGF-B secretion. Furthermore, we have identified the acyl protein thioesterase APT-1 as a determinant of thyroid tumor growth versus dissemination. We show that alterations in APT-1 expression levels can dramatically affect the behavior of thyroid tumors, based on its role as a regulator of HRAS sublocalization at distinct plasma membrane microdomains. In agreement, APT-1 emerges in thyroid cancer clinical samples as a prognostic factor. As such, APT-1 levels could serve as a biomarker that could help in the stratification of HRAS mutant thyroid tumors based on their aggressiveness.
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Affiliation(s)
- Yaiza García-Ibáñez
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Cantabria. Santander, E-39011 Cantabria, Spain; (Y.G.-I.); (B.C.)
| | - Garcilaso Riesco-Eizaguirre
- Instituto de Investigaciones Biomédicas “Alberto Sols”, Consejo Superior de Investigaciones Científicas -Universidad Autónoma de Madrid. E-28029 Madrid, Spain; (G.R.-E.); (P.S.)
- Departamento de Endocrinología y Nutrición, Hospital Universitario de Móstoles, E-28935 Madrid, Spain
- Departamento de Endocrinología Molecular, Universidad Francisco de Vitoria, E-28223 Madrid, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Pilar Santisteban
- Instituto de Investigaciones Biomédicas “Alberto Sols”, Consejo Superior de Investigaciones Científicas -Universidad Autónoma de Madrid. E-28029 Madrid, Spain; (G.R.-E.); (P.S.)
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Berta Casar
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Cantabria. Santander, E-39011 Cantabria, Spain; (Y.G.-I.); (B.C.)
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Piero Crespo
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Cantabria. Santander, E-39011 Cantabria, Spain; (Y.G.-I.); (B.C.)
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence:
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11
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Keyes J, Ganesan A, Molinar-Inglis O, Hamidzadeh A, Zhang J, Ling M, Trejo J, Levchenko A, Zhang J. Signaling diversity enabled by Rap1-regulated plasma membrane ERK with distinct temporal dynamics. eLife 2020; 9:57410. [PMID: 32452765 PMCID: PMC7289600 DOI: 10.7554/elife.57410] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/22/2020] [Indexed: 12/23/2022] Open
Abstract
A variety of different signals induce specific responses through a common, extracellular-signal regulated kinase (ERK)-dependent cascade. It has been suggested that signaling specificity can be achieved through precise temporal regulation of ERK activity. Given the wide distrubtion of ERK susbtrates across different subcellular compartments, it is important to understand how ERK activity is temporally regulated at specific subcellular locations. To address this question, we have expanded the toolbox of Förster Resonance Energy Transfer (FRET)-based ERK biosensors by creating a series of improved biosensors targeted to various subcellular regions via sequence specific motifs to measure spatiotemporal changes in ERK activity. Using these sensors, we showed that EGF induces sustained ERK activity near the plasma membrane in sharp contrast to the transient activity observed in the cytoplasm and nucleus. Furthermore, EGF-induced plasma membrane ERK activity involves Rap1, a noncanonical activator, and controls cell morphology and EGF-induced membrane protrusion dynamics. Our work strongly supports that spatial and temporal regulation of ERK activity is integrated to control signaling specificity from a single extracellular signal to multiple cellular processes.
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Affiliation(s)
- Jeremiah Keyes
- Department of Pharmacology, University of California San Diego, La Jolla, United States
| | - Ambhighainath Ganesan
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Olivia Molinar-Inglis
- Department of Pharmacology, University of California San Diego, La Jolla, United States
| | - Archer Hamidzadeh
- Department of Biomedical Engineering and Yale Systems Biology Institute, Yale University, New Haven, United States
| | - Jinfan Zhang
- Department of Pharmacology, University of California San Diego, La Jolla, United States
| | - Megan Ling
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, United States
| | - JoAnn Trejo
- Department of Pharmacology, University of California San Diego, La Jolla, United States
| | - Andre Levchenko
- Department of Biomedical Engineering and Yale Systems Biology Institute, Yale University, New Haven, United States
| | - Jin Zhang
- Department of Pharmacology, University of California San Diego, La Jolla, United States.,Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, United States.,Department of Bioengineering, University of California San Diego, La Jolla, United States
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12
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Reder H, Wagner S, Gamerdinger U, Sandmann S, Wuerdemann N, Braeuninger A, Dugas M, Gattenloehner S, Klussmann JP, Wittekindt C. Genetic alterations in human papillomavirus-associated oropharyngeal squamous cell carcinoma of patients with treatment failure. Oral Oncol 2019; 93:59-65. [PMID: 31109697 DOI: 10.1016/j.oraloncology.2019.04.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/15/2019] [Accepted: 04/22/2019] [Indexed: 01/15/2023]
Abstract
OBJECTIVES Despite improved survival rates of patients with HPV-associated OPSCC, a subset has distant metastasis or develops local recurrence during follow-up. To investigate potential underlying genetic alterations, we analyzed patients with HPV-driven OPSCC who suffered from recurrence in comparison to matching pairs with successful tumor control. MATERIALS AND METHODS We performed chromosomal copy number analyses and targeted next generation sequencing using a custom panel comprising genes that are frequently mutated in HPV-associated OPSCC. RESULTS Specific differences regarding chromosomal aberrations were not observed between both groups. In HPV-driven OPSCC from patients with recurrence we found higher mutation rates compared to patients with successful tumor control. Especially mutation rates of HRAS (p ≤ 0.05) PIK3R1, STK11 and TP63 (p ≤ 0.1 each) were statistically significant or trending towards significance. The respective genes can be linked to transcription factors and signaling pathways involved in cell cycle regulation, proliferation and survival. Additionally, combinations of alterations were observed on chromosomes 16 and 19, which might also influence outcome. CONCLUSION Patients with HPV-driven OPSCC who develop recurrence or have metastasis may be defined by genetic alterations that might be responsible for poor outcome after standard therapy. This might be of importance for stratification in future de-escalation and targeted therapy.
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Affiliation(s)
- Henrike Reder
- Department of Otorhinolaryngology, Head and Neck Surgery, Justus-Liebig University Giessen, 35392 Giessen, Germany.
| | - Steffen Wagner
- Department of Otorhinolaryngology, Head and Neck Surgery, Justus-Liebig University Giessen, 35392 Giessen, Germany
| | - Ulrike Gamerdinger
- Department of Pathology, Justus-Liebig University Giessen, 35392 Giessen, Germany
| | - Sarah Sandmann
- Institute of Medical Informatics, Westphalian Wilhelms University Muenster, 48149 Muenster, Germany
| | - Nora Wuerdemann
- Department of Otorhinolaryngology, Head and Neck Surgery, Justus-Liebig University Giessen, 35392 Giessen, Germany; Department of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University Hospital Cologne, 50931 Cologne, Germany
| | - Andreas Braeuninger
- Department of Pathology, Justus-Liebig University Giessen, 35392 Giessen, Germany
| | - Martin Dugas
- Institute of Medical Informatics, Westphalian Wilhelms University Muenster, 48149 Muenster, Germany
| | - Stefan Gattenloehner
- Department of Pathology, Justus-Liebig University Giessen, 35392 Giessen, Germany
| | - Jens Peter Klussmann
- Department of Otorhinolaryngology, Head and Neck Surgery, Justus-Liebig University Giessen, 35392 Giessen, Germany; Department of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University Hospital Cologne, 50931 Cologne, Germany
| | - Claus Wittekindt
- Department of Otorhinolaryngology, Head and Neck Surgery, Justus-Liebig University Giessen, 35392 Giessen, Germany
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13
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Mendoza P, Martínez-Martín N, Bovolenta ER, Reyes-Garau D, Hernansanz-Agustín P, Delgado P, Diaz-Muñoz MD, Oeste CL, Fernández-Pisonero I, Castellano E, Martínez-Ruiz A, Alonso-Lopez D, Santos E, Bustelo XR, Kurosaki T, Alarcón B. R-Ras2 is required for germinal center formation to aid B cells during energetically demanding processes. Sci Signal 2018; 11:11/532/eaal1506. [DOI: 10.1126/scisignal.aal1506] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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14
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The Yeast Saccharomyces cerevisiae as a Model for Understanding RAS Proteins and their Role in Human Tumorigenesis. Cells 2018; 7:cells7020014. [PMID: 29463063 PMCID: PMC5850102 DOI: 10.3390/cells7020014] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 02/05/2018] [Accepted: 02/12/2018] [Indexed: 12/16/2022] Open
Abstract
The exploitation of the yeast Saccharomyces cerevisiae as a biological model for the investigation of complex molecular processes conserved in multicellular organisms, such as humans, has allowed fundamental biological discoveries. When comparing yeast and human proteins, it is clear that both amino acid sequences and protein functions are often very well conserved. One example of the high degree of conservation between human and yeast proteins is highlighted by the members of the RAS family. Indeed, the study of the signaling pathways regulated by RAS in yeast cells led to the discovery of properties that were often found interchangeable with RAS proto-oncogenes in human pathways, and vice versa. In this work, we performed an updated critical literature review on human and yeast RAS pathways, specifically highlighting the similarities and differences between them. Moreover, we emphasized the contribution of studying yeast RAS pathways for the understanding of human RAS and how this model organism can contribute to unveil the roles of RAS oncoproteins in the regulation of mechanisms important in the tumorigenic process, like autophagy.
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15
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Abstract
How do Ras isoforms attain oncogenic specificity at the membrane? Oncogenic KRas, HRas, and NRas (K-Ras, H-Ras, and N-Ras) differentially populate distinct cancers. How they selectively activate effectors and why is KRas4B the most prevalent are highly significant questions. Here, we consider determinants that may bias isoform-specific effector activation and signaling at the membrane. We merge functional data with a conformational view to provide mechanistic insight. Cell-specific expression levels, pathway cross-talk, and distinct interactions are the key, but conformational trends can modulate selectivity. There are two major pathways in oncogenic Ras-driven proliferation: MAPK (Raf/MEK/ERK) and PI3Kα/Akt/mTOR. All membrane-anchored, proximally located, oncogenic Ras isoforms can promote Raf dimerization and fully activate MAPK signaling. So why the differential statistics of oncogenic isoforms in distinct cancers and what makes KRas so highly oncogenic? Many cell-specific factors may be at play, including higher KRAS mRNA levels. As a key factor, we suggest that because only KRas4B binds calmodulin, only KRas can fully activate PI3Kα/Akt signaling. We propose that full activation of both MAPK and PI3Kα/Akt proliferative pathways by oncogenic KRas4B-but not by HRas or NRas-may help explain why the KRas4B isoform is especially highly populated in certain cancers. We further discuss pharmacologic implications. Cancer Res; 78(3); 593-602. ©2017 AACR.
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Affiliation(s)
- Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland. .,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland
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16
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Nussinov R, Tsai CJ, Jang H. Oncogenic Ras Isoforms Signaling Specificity at the Membrane. Cancer Res 2018; 78:593-602. [PMID: 29273632 PMCID: PMC5811325 DOI: 10.1158/0008-5472.can-17-2727] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/13/2017] [Accepted: 11/10/2017] [Indexed: 01/21/2023]
Abstract
How do Ras isoforms attain oncogenic specificity at the membrane? Oncogenic KRas, HRas, and NRas (K-Ras, H-Ras, and N-Ras) differentially populate distinct cancers. How they selectively activate effectors and why is KRas4B the most prevalent are highly significant questions. Here, we consider determinants that may bias isoform-specific effector activation and signaling at the membrane. We merge functional data with a conformational view to provide mechanistic insight. Cell-specific expression levels, pathway cross-talk, and distinct interactions are the key, but conformational trends can modulate selectivity. There are two major pathways in oncogenic Ras-driven proliferation: MAPK (Raf/MEK/ERK) and PI3Kα/Akt/mTOR. All membrane-anchored, proximally located, oncogenic Ras isoforms can promote Raf dimerization and fully activate MAPK signaling. So why the differential statistics of oncogenic isoforms in distinct cancers and what makes KRas so highly oncogenic? Many cell-specific factors may be at play, including higher KRAS mRNA levels. As a key factor, we suggest that because only KRas4B binds calmodulin, only KRas can fully activate PI3Kα/Akt signaling. We propose that full activation of both MAPK and PI3Kα/Akt proliferative pathways by oncogenic KRas4B-but not by HRas or NRas-may help explain why the KRas4B isoform is especially highly populated in certain cancers. We further discuss pharmacologic implications. Cancer Res; 78(3); 593-602. ©2017 AACR.
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Affiliation(s)
- Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland.
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland
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17
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Herrero A, Reis-Cardoso M, Jiménez-Gómez I, Doherty C, Agudo-Ibañez L, Pinto A, Calvo F, Kolch W, Crespo P, Matallanas D. Characterisation of HRas local signal transduction networks using engineered site-specific exchange factors. Small GTPases 2018; 11:371-383. [PMID: 29172991 DOI: 10.1080/21541248.2017.1406434] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Ras GTPases convey signals from different types of membranes. At these locations, different Ras isoforms, interactors and regulators generate different biochemical signals and biological outputs. The study of Ras localisation-specific signal transduction networks has been hampered by our inability to specifically activate each of these Ras pools. Here, we describe a new set of site-specific tethered exchange factors, engineered by fusing the RasGRF1 CDC25 domain to sub-localisation-defining cues, whereby Ras pools at specific locations can be precisely activated. We show that the CDC25 domain has a high specificity for activating HRas but not NRas and KRas. This unexpected finding means that our constructs mainly activate endogenous HRas. Hence, their use enabled us to identify distinct pathways regulated by HRas in endomembranes and plasma membrane microdomains. Importantly, these new constructs unveil different patterns of HRas activity specified by their subcellular localisation. Overall, the targeted GEFs described herein constitute ideal tools for dissecting spatially-defined HRas biochemical and biological functions.
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Affiliation(s)
- Ana Herrero
- Systems Biology Ireland, University College Dublin , Dublin, Ireland.,School of Medicine and Medical Science, University College Dublin , Dublin, Ireland
| | | | - Iñaki Jiménez-Gómez
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Cantabria, Santander , Spain
| | - Carolanne Doherty
- Systems Biology Ireland, University College Dublin , Dublin, Ireland.,School of Medicine and Medical Science, University College Dublin , Dublin, Ireland
| | - Lorena Agudo-Ibañez
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Cantabria, Santander , Spain
| | - Adán Pinto
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Cantabria, Santander , Spain
| | - Fernando Calvo
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Cantabria, Santander , Spain
| | - Walter Kolch
- Systems Biology Ireland, University College Dublin , Dublin, Ireland.,Conway Institute, University College Dublin , Dublin, Ireland.,School of Medicine and Medical Science, University College Dublin , Dublin, Ireland
| | - Piero Crespo
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Cantabria, Santander , Spain.,Centro de Investigación Biomédica en Red CIBERONC, Instituto de Salud Calos III , Madrid, Spain
| | - David Matallanas
- Systems Biology Ireland, University College Dublin , Dublin, Ireland.,School of Medicine and Medical Science, University College Dublin , Dublin, Ireland
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18
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Agudo-Ibañez L, Crespo P, Casar B. Analysis of Ras/ERK Compartmentalization by Subcellular Fractionation. Methods Mol Biol 2018; 1487:151-162. [PMID: 27924565 DOI: 10.1007/978-1-4939-6424-6_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
A vast number of stimuli use the Ras/Raf/MEK/ERK signaling cascade to transmit signals from their cognate receptors, in order to regulate multiple cellular functions, including key processes such as proliferation, cell cycle progression, differentiation, and survival. The duration, intensity and specificity of the responses are, in part, controlled by the compartmentalization/subcellular localization of the signaling intermediaries. Ras proteins are found in different plasma membrane microdomains and endomembranes. At these localizations, Ras is subject to site-specific regulatory mechanisms, distinctively engaging effector pathways and switching-on diverse genetic programs to generate a multitude of biological responses. The Ras effector pathway leading to ERKs activation is also subject to space-related regulatory processes. About half of ERK1/2 substrates are found in the nucleus and function mainly as transcription factors. The other half resides in the cytosol and other cellular organelles. Such subcellular distribution enhances the complexity of the Ras/ERK cascade and constitutes an essential mechanism to endow variability to its signals, which enables their participation in the regulation of a broad variety of functions. Thus, analyzing the subcellular compartmentalization of the members of the Ras/ERK cascade constitutes an important factor to be taken into account when studying specific biological responses evoked by Ras/ERK signals. Herein, we describe methods for such purpose.
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Affiliation(s)
- Lorena Agudo-Ibañez
- Instituto de Biomedicina y Biotecnología de Cantabria, Consejo Superior de Investigaciones Científicas - Universidad de Cantabria, c/Albert Einstein, 22, PCTCAN, Santander, 39011, Cantabria, Spain
| | - Piero Crespo
- Instituto de Biomedicina y Biotecnología de Cantabria, Consejo Superior de Investigaciones Científicas - Universidad de Cantabria, c/Albert Einstein, 22, PCTCAN, Santander, 39011, Cantabria, Spain
| | - Berta Casar
- Instituto de Biomedicina y Biotecnología de Cantabria, Consejo Superior de Investigaciones Científicas - Universidad de Cantabria, c/Albert Einstein, 22, PCTCAN, Santander, 39011, Cantabria, Spain.
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19
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Shishina AK, Kovrigina EA, Galiakhmetov AR, Rathore R, Kovrigin EL. Study of Förster Resonance Energy Transfer to Lipid Domain Markers Ascertains Partitioning of Semisynthetic Lipidated N-Ras in Lipid Raft Nanodomains. Biochemistry 2018; 57:872-881. [PMID: 29280621 DOI: 10.1021/acs.biochem.7b01181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cellular membranes are heterogeneous planar lipid bilayers displaying lateral phase separation with the nanometer-scale liquid-ordered phase (also known as "lipid rafts") surrounded by the liquid-disordered phase. Many membrane-associated proteins were found to permanently integrate into the lipid rafts, which is critical for their biological function. Isoforms H and N of Ras GTPase possess a unique ability to switch their lipid domain preference depending on the type of bound guanine nucleotide (GDP or GTP). This behavior, however, has never been demonstrated in vitro in model bilayers with recombinant proteins and therefore has been attributed to the action of binding of Ras to other proteins at the membrane surface. In this paper, we report the observation of the nucleotide-dependent switch of lipid domain preferences of the semisynthetic lipidated N-Ras in lipid raft vesicles in the absence of additional proteins. To detect segregation of Ras molecules in raft and disordered lipid domains, we measured Förster resonance energy transfer between the donor fluorophore, mant, attached to the protein-bound guanine nucleotides, and the acceptor, rhodamine-conjugated lipid, localized into the liquid-disordered domains. Herein, we established that N-Ras preferentially populated raft domains when bound to mant-GDP, while losing its preference for rafts when it was associated with a GTP mimic, mant-GppNHp. At the same time, the isolated lipidated C-terminal peptide of N-Ras was found to be localized outside of the liquid-ordered rafts, most likely in the bulk-disordered lipid. Substitution of the N-terminal G domain of N-Ras with a homologous G domain of H-Ras disrupted the nucleotide-dependent lipid domain switch.
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Affiliation(s)
- Anna K Shishina
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Elizaveta A Kovrigina
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Azamat R Galiakhmetov
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Rajendra Rathore
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Evgenii L Kovrigin
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
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20
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Bi C, Tham DKL, Perronnet C, Joshi B, Nabi IR, Moukhles H. The Oxidative Stress-Induced Increase in the Membrane Expression of the Water-Permeable Channel Aquaporin-4 in Astrocytes Is Regulated by Caveolin-1 Phosphorylation. Front Cell Neurosci 2017; 11:412. [PMID: 29326556 PMCID: PMC5742350 DOI: 10.3389/fncel.2017.00412] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 12/08/2017] [Indexed: 01/14/2023] Open
Abstract
The reperfusion of ischemic brain tissue following a cerebral stroke causes oxidative stress, and leads to the generation of reactive oxygen species (ROS). Apart from inflicting oxidative damage, the latter may also trigger the upregulation of aquaporin 4 (AQP4), a water-permeable channel expressed by astroglial cells of the blood-brain barrier (BBB), and contribute to edema formation, the severity of which is known to be the primary determinant of mortality and morbidity. The mechanism through which this occurs remains unknown. In the present study, we have attempted to address this question using primary astrocyte cultures treated with hydrogen peroxide (H2O2) as a model system. First, we showed that H2O2 induces a significant increase in AQP4 protein levels and that this is inhibited by the antioxidant N-acetylcysteine (NAC). Second, we demonstrated using cell surface biotinylation that H2O2 increases AQP4 cell-surface expression independently of it's increased synthesis. In parallel, we found that caveolin-1 (Cav1) is phosphorylated in response to H2O2 and that this is reversed by the Src kinase inhibitor 4-Amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2). PP2 also abrogated the H2O2-induced increase in AQP4 surface levels, suggesting that the phosphorylation of tyrosine-14 of Cav1 regulates this process. We further showed that dominant-negative Y14F and phosphomimetic Y14D mutants caused a decrease and increase in AQP4 membrane expression respectively, and that the knockdown of Cav1 inhibits the increase in AQP4 cell-surface, expression following H2O2 treatment. Together, these findings suggest that oxidative stress-induced Cav1 phosphorylation modulates AQP4 subcellular distribution and therefore may indirectly regulate AQP4-mediated water transport.
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Affiliation(s)
- Chongshan Bi
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Daniel K L Tham
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Caroline Perronnet
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Bharat Joshi
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Ivan R Nabi
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Hakima Moukhles
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
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21
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Concepts and advances in cancer therapeutic vulnerabilities in RAS membrane targeting. Semin Cancer Biol 2017; 54:121-130. [PMID: 29203271 DOI: 10.1016/j.semcancer.2017.11.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 11/30/2017] [Indexed: 01/05/2023]
Abstract
For decades oncogenic RAS proteins were considered undruggable due to a lack of accessible binding pockets on the protein surfaces. Seminal early research in RAS biology uncovered the basic paradigm of post-translational isoprenylation of RAS polypeptides, typically with covalent attachment of a farnesyl group, leading to isoprenyl-mediated RAS anchorage at the plasma membrane and signal initiation at those sites. However, the failure of farnesyltransferase inhibitors to translate to the clinic stymied anti-RAS therapy development. Over the past ten years, a more complete picture has emerged of RAS protein maturation, intracellular trafficking, and location, positioning and retention in subdomains at the plasma membrane, with a corresponding expansion in our understanding of how these properties of RAS contribute to signal outputs. Each of these aspects of RAS regulation presents a potential vulnerability in RAS function that may be exploited for therapeutic targeting, and inhibitors have been identified or developed that interfere with RAS for nearly all of them. This review will summarize current understanding of RAS membrane targeting with a focus on highlighting development and outcomes of inhibitors at each step.
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22
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Schmukler E, Wolfson E, Elazar Z, Kloog Y, Pinkas-Kramarski R. Continuous treatment with FTS confers resistance to apoptosis and affects autophagy. PLoS One 2017; 12:e0171351. [PMID: 28151959 PMCID: PMC5289601 DOI: 10.1371/journal.pone.0171351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 01/19/2017] [Indexed: 12/26/2022] Open
Abstract
High percentage of human cancers involves alteration or mutation in Ras proteins, including the most aggressive malignancies, such as lung, colon and pancreatic cancers. FTS (Salirasib) is a farnesylcysteine mimetic, which acts as a functional Ras inhibitor, and was shown to exert anti-tumorigenic effects in vitro and in vivo. Previously, we have demonstrated that short-term treatment with FTS also induces protective autophagy in several cancer cell lines. Drug resistance is frequently observed in cancer cells exposed to prolonged treatment, and is considered a major cause for therapy inefficiency. Therefore, in the present study, we examined the effect of a prolonged treatment with FTS on drug resistance of HCT-116 human colon cancer cells, and the involvement of autophagy in this process. We found that cells grown in the presence of FTS for 6 months have become resistant to FTS-induced cell growth inhibition and cell death. Furthermore, we discovered that the resistant cells exhibit altered autophagy, reduced apoptosis and changes in Ras-related signaling pathways following treatment with FTS. Moreover we found that while FTS induces an apoptosis-related cleavage of p62, the FTS-resistant cells were more resistant to apoptosis and p62 cleavage.
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Affiliation(s)
- Eran Schmukler
- Department of Neurobiology. Tel-Aviv University, Ramat-Aviv, Israel
| | - Eya Wolfson
- Department of Neurobiology. Tel-Aviv University, Ramat-Aviv, Israel
| | - Zvulun Elazar
- Department of Biological Chemistry; The Weizmann Institute of Science; Rehovot, Israel
| | - Yoel Kloog
- Department of Neurobiology. Tel-Aviv University, Ramat-Aviv, Israel
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23
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Rohlenova K, Neuzil J, Rohlena J. The role of Her2 and other oncogenes of the PI3K/AKT pathway in mitochondria. Biol Chem 2016; 397:607-15. [DOI: 10.1515/hsz-2016-0130] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/13/2016] [Indexed: 01/01/2023]
Abstract
Abstract
Altered metabolism and resistance to cell death are typical hallmarks of cancer phenotype. Mitochondria are organelles central to cellular metabolism as well as to cell death induction. Hyperactivation of pro-survival and pro-proliferative pathways such as PI3K/AKT leads to cancer initiation, which affects mitochondria. Growing body of evidence indicates that oncogenes such as HER2, EGFR and RAS, as well as the downstream members of the PI3K/AKT signaling pathway, directly regulate mitochondria by translocating to the organelle. Here we discuss evidence of this scenario and consider mechanisms for direct regulation of mitochondrial function. Being in close proximity to mitochondrial bioenergetics machinery as well as to the regulators/executors of programed cell death, oncogenes in mitochondria may be ideally placed to perform this task. This represents a thus far under-explored area, which may be relevant to better understanding of cancer initiation, progression and treatment.
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24
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Fey D, Matallanas D, Rauch J, Rukhlenko OS, Kholodenko BN. The complexities and versatility of the RAS-to-ERK signalling system in normal and cancer cells. Semin Cell Dev Biol 2016; 58:96-107. [PMID: 27350026 DOI: 10.1016/j.semcdb.2016.06.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 06/18/2016] [Indexed: 12/19/2022]
Abstract
The intricate dynamic control and plasticity of RAS to ERK mitogenic, survival and apoptotic signalling has mystified researches for more than 30 years. Therapeutics targeting the oncogenic aberrations within this pathway often yield unsatisfactory, even undesired results, as in the case of paradoxical ERK activation in response to RAF inhibition. A direct approach of inhibiting single oncogenic proteins misses the dynamic network context governing the network signal processing. In this review, we discuss the signalling behaviour of RAS and RAF proteins in normal and in cancer cells, and the emerging systems-level properties of the RAS-to-ERK signalling network. We argue that to understand the dynamic complexities of this control system, mathematical models including mechanistic detail are required. Looking into the future, these dynamic models will build the foundation upon which more effective, rational approaches to cancer therapy will be developed.
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Affiliation(s)
- Dirk Fey
- Systems Biology Ireland, UCD School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
| | - David Matallanas
- Systems Biology Ireland, UCD School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Jens Rauch
- Systems Biology Ireland, UCD School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Oleksii S Rukhlenko
- Systems Biology Ireland, UCD School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Boris N Kholodenko
- Systems Biology Ireland, UCD School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
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25
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Regulation of H-Ras-driven MAPK signaling, transformation and tumorigenesis, but not PI3K signaling and tumor progression, by plasma membrane microdomains. Oncogenesis 2016; 5:e228. [PMID: 27239960 PMCID: PMC4945753 DOI: 10.1038/oncsis.2016.36] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 04/17/2016] [Indexed: 12/16/2022] Open
Abstract
In this study, we assessed the contributions of plasma membrane (PM) microdomain targeting to the functions of H-Ras and R-Ras. These paralogs have identical effector-binding regions, but variant C-terminal targeting domains (tDs) which are responsible for lateral microdomain distribution: activated H-Ras targets to lipid ordered/disordered (Lo/Ld) domain borders, and R-Ras to Lo domains (rafts). We hypothesized that PM distribution regulates Ras-effector interactions and downstream signaling. We used tD swap mutants, and assessed effects on signal transduction, cell proliferation, transformation and tumorigenesis. R-Ras harboring the H-Ras tD (R-Ras-tH) interacted with Raf, and induced Raf and ERK phosphorylation similar to H-Ras. R-Ras-tH stimulated proliferation and transformation in vitro, and these effects were blocked by both MEK and PI3K inhibition. Conversely, the R-Ras tD suppressed H-Ras-mediated Raf activation and ERK phosphorylation, proliferation and transformation. Thus, Ras access to Raf at the PM is sufficient for MAPK activation and is a principal component of Ras mitogenesis and transformation. Fusion of the R-Ras extended N-terminal domain to H-Ras had no effect on proliferation, but inhibited transformation and tumor progression, indicating that the R-Ras N-terminus also contributes negative regulation to these Ras functions. PI3K activation was tD independent; however, H-Ras was a stronger activator of PI3K than R-Ras, with either tD. PI3K inhibition nearly ablated transformation by R-Ras-tH, H-Ras and H-Ras-tR, whereas MEK inhibition had a modest effect on Ras-tH-driven transformation but no effect on H-Ras-tR transformation. R-Ras-tH supported tumor initiation, but not tumor progression. While H-Ras-tR-induced transformation was reduced relative to H-Ras, tumor progression was robust and similar to H-Ras. H-Ras tumor growth was moderately suppressed by MEK inhibition, which had no effect on H-Ras-tR tumor growth. In contrast, PI3K inhibition markedly suppressed tumor growth by H-Ras and H-Ras-tR, indicating that sustained PI3K signaling is a critical pathway for H-Ras-driven tumor progression, independent of microdomains.
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Bender RHF, Haigis KM, Gutmann DH. Activated k-ras, but not h-ras or N-ras, regulates brain neural stem cell proliferation in a raf/rb-dependent manner. Stem Cells 2016; 33:1998-2010. [PMID: 25788415 DOI: 10.1002/stem.1990] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 02/08/2015] [Accepted: 02/19/2015] [Indexed: 12/19/2022]
Abstract
Neural stem cells (NSCs) give rise to all the major cell types in the brain, including neurons, oligodendrocytes, and astrocytes. However, the intracellular signaling pathways that govern brain NSC proliferation and differentiation have been incompletely characterized to date. Since some neurodevelopmental brain disorders (Costello syndrome and Noonan syndrome) are caused by germline activating mutations in the RAS genes, Ras small GTPases are likely critical regulators of brain NSC function. In the mammalian brain, Ras exists as three distinct molecules (H-Ras, K-Ras, and N-Ras), each with different subcellular localizations, downstream signaling effectors, and biological effects. Leveraging a novel series of conditional-activated Ras molecule-expressing genetically engineered mouse strains, we demonstrate that activated K-Ras, but not H-Ras or N-Ras, expression increases brain NSC growth in a Raf-dependent, but Mek-independent, manner. Moreover, we show that activated K-Ras regulation of brain NSC proliferation requires Raf binding and suppression of retinoblastoma (Rb) function. Collectively, these observations establish tissue-specific differences in activated Ras molecule regulation of brain cell growth that operate through a noncanonical mechanism.
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Affiliation(s)
- R Hugh F Bender
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kevin M Haigis
- Department of Medicine, Cancer Research Institute, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - David H Gutmann
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
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27
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Muñoz-Félix JM, Fuentes-Calvo I, Cuesta C, Eleno N, Crespo P, López-Novoa JM, Martínez-Salgado C. Absence of K-Ras Reduces Proliferation and Migration But Increases Extracellular Matrix Synthesis in Fibroblasts. J Cell Physiol 2016; 231:2224-35. [PMID: 26873620 DOI: 10.1002/jcp.25340] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 02/10/2016] [Indexed: 02/06/2023]
Abstract
The involvement of Ras-GTPases in the development of renal fibrosis has been addressed in the last decade. We have previously shown that H- and N-Ras isoforms participate in the regulation of fibrosis. Herein, we assessed the role of K-Ras in cellular processes involved in the development of fibrosis: proliferation, migration, and extracellular matrix (ECM) proteins synthesis. K-Ras knockout (KO) mouse embryonic fibroblasts (K-ras(-/-) ) stimulated with transforming growth factor-β1 (TGF-β1) exhibited reduced proliferation and impaired mobility than wild-type fibroblasts. Moreover, an increase on ECM production was observed in K-Ras KO fibroblasts in basal conditions. The absence of K-Ras was accompanied by reduced Ras activation and ERK phosphorylation, and increased AKT phosphorylation, but no differences were observed in TGF-β1-induced Smad signaling. The MEK inhibitor U0126 decreased cell proliferation independently of the presence of K-ras but reduced migration and ECM proteins expression only in wild-type fibroblasts, while the PI3K-AKT inhibitor LY294002 decreased cell proliferation, migration, and ECM synthesis in both types of fibroblasts. Thus, our data unveil that K-Ras and its downstream effector pathways distinctively regulate key biological processes in the development of fibrosis. Moreover, we show that K-Ras may be a crucial mediator in TGF-β1-mediated effects in this cell type. J. Cell. Physiol. 231: 2224-2235, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- José M Muñoz-Félix
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Isabel Fuentes-Calvo
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Cristina Cuesta
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Nélida Eleno
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Piero Crespo
- Facultad de Medicina, Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, Consejo Superior de Investigaciones Científicas-IDICAN-Universidad de Cantabria, Santander, Spain
| | - José M López-Novoa
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Carlos Martínez-Salgado
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain.,Instituto de Estudios de Ciencias de la Salud de Castilla y León (IECSCYL), Unidad de Investigación, Hospital Universitario de Salamanca, Salamanca, Spain
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28
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Porrello A, Piergentili RB. Contextualizing the Genes Altered in Bladder Neoplasms in Pediatric andTeen Patients Allows Identifying Two Main Classes of Biological ProcessesInvolved and New Potential Therapeutic Targets. Curr Genomics 2016; 17:33-61. [PMID: 27013923 PMCID: PMC4780474 DOI: 10.2174/1389202916666151014222603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 06/29/2015] [Accepted: 07/08/2015] [Indexed: 12/19/2022] Open
Abstract
Research on bladder neoplasms in pediatric and teen patients (BNPTP) has described 21 genes, which are variously involved in this disease and are mostly responsible for deregulated cell proliferation. However, due to the limited number of publications on this subject, it is still unclear what type of relationships there are among these genes and which are the chances that, while having different molecular functions, they i) act as downstream effector genes of well-known pro- or anti- proliferative stimuli and/or interplay with biochemical pathways having oncological relevance or ii) are specific and, possibly, early biomarkers of these pathologies. A Gene Ontology (GO)-based analysis showed that these 21 genes are involved in biological processes, which can be split into two main classes: cell regulation-based and differentiation/development-based. In order to understand the involvement/overlapping with main cancer-related pathways, we performed a meta-analysis dependent on the 189 oncogenic signatures of the Molecular Signatures Database (OSMSD) curated by the Broad Institute. We generated a binary matrix with 53 gene signatures having at least one hit; this analysis i) suggests that some genes of the original list show inconsistencies and might need to be experimentally re- assessed or evaluated as biomarkers (in particular, ACTA2) and ii) allows hypothesizing that important (proto)oncogenes (E2F3, ERBB2/HER2, CCND1, WNT1, and YAP1) and (putative) tumor suppressors (BRCA1, RBBP8/CTIP, and RB1-RBL2/p130) may participate in the onset of this disease or worsen the observed phenotype, thus expanding the list of possible molecular targets for the treatment of BNPTP.
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Affiliation(s)
- A. Porrello
- Comprehensive Cancer Center (LCCC), University of North Carolina (UNC)-Chapel Hill, Chapel Hill, 27599 NC, USA
| | - R. b Piergentili
- Institute of Molecular Biology and Pathology at CNR (CNR-IBPM); Department of Biology and Biotechnologies, Sapienza – Università di Roma, Italy
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29
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Zangari A, Zaini J, Gulìa C. Genetics of Bladder Malignant Tumors in Childhood. Curr Genomics 2016; 17:14-32. [PMID: 27013922 PMCID: PMC4780472 DOI: 10.2174/1389202916666151014221954] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/25/2015] [Accepted: 06/30/2015] [Indexed: 12/30/2022] Open
Abstract
Bladder masses are represented by either benign or malignant entities. Malignant bladder tumors are frequent causes of disease and death in western countries. However, in children they are less common. Additionally, different features are found in childhood, in which non epithelial tumors are more common than epithelial ones. Rhabdomyosarcoma is the most common pediatric bladder tumor, but many other types of lesions may be found, such as malignant rhabdoid tumor (MRT), inflammatory myofibroblastic tumor and neuroblastoma. Other rarer tumors described in literature include urothelial carcinoma and other epithelial neoplasms. Rhabdomyosarcoma is associated to a variety of genetic syndromes and many genes are involved in tumor development. PAX3-FKHR and PAX7-FKHR (P-F) fusion state has important implications in the pathogenesis and biology of RMS, and different genes alterations are involved in the pathogenesis of P-F negative and embryonal RMS, which are the subsets of tumors most frequently affecting the bladder. These genes include p53, MEF2, MYOG, Ptch1, Gli1, Gli3, Myf5, MyoD1, NF1, NRAS, KRAS, HRAS, FGFR4, PIK3CA, CTNNB1, FBXW7, IGF1R, PDGFRA, ERBB2/4, MET, BCOR. Malignant rhabdoid tumor (MRT) usually shows SMARCB1/INI1 alterations. Anaplastic lymphoma kinase (ALK) gene translocations are the most frequently associated alterations in inflammatory myofibroblastic tumor (IMT). Few genes alterations in urothelial neoplasms have been reported in the paediatric population, which are mainly related to deletion of p16/lnk4, overexpression of CK20 and overexpression of p53. Here, we reviewed available literature to identify genes associated to bladder malignancies in children and discussed their possible relationships with these tumors.
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Affiliation(s)
| | - Johan Zaini
- Università degli Studi della Tuscia, dipartimento di scienze biologiche (DEB), Viterbo, Italy
| | - Caterina Gulìa
- Università degli Studi di Roma La Sapienza, Dipartimento di Urologia, Roma, Italy
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30
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Banerjee A, Jang H, Nussinov R, Gaponenko V. The disordered hypervariable region and the folded catalytic domain of oncogenic K-Ras4B partner in phospholipid binding. Curr Opin Struct Biol 2016; 36:10-7. [PMID: 26709496 PMCID: PMC4785042 DOI: 10.1016/j.sbi.2015.11.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/20/2015] [Indexed: 01/08/2023]
Abstract
The C-terminal hypervariable region (HVR) of the splice variant KRAS4B is disordered. Classically, the role of the post-translationally-modified HVR is to navigate Ras in the cell and to anchor it in localized plasma membrane regions. Here, we propose additional regulatory roles, including auto-inhibition by shielding the effector binding site in the GDP-bound state and release upon GTP binding and in the presence of certain oncogenic mutations. The released HVR can interact with calmodulin. We show that oncogenic mutations (G12V/G12D) modulate the HVR-phospholipid binding specificity, resulting in preferential interactions with phosphatidic acid. The shifts in the conformational preferences and binding specificity in the disordered state exemplify the critical role of the unstructured tail of K-Ras4B in cancer.
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Affiliation(s)
- Avik Banerjee
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Hyunbum Jang
- Cancer and Inflammation Program, National Cancer Institute at Frederick, Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Ruth Nussinov
- Cancer and Inflammation Program, National Cancer Institute at Frederick, Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA.
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31
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Classic Ras Proteins Promote Proliferation and Survival via Distinct Phosphoproteome Alterations in Neurofibromin-Null Malignant Peripheral Nerve Sheath Tumor Cells. J Neuropathol Exp Neurol 2015; 74:568-86. [PMID: 25946318 DOI: 10.1097/nen.0000000000000201] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Neurofibromin, the tumor suppressor encoded by the neurofibromatosis type 1 (NF1) gene, potentially suppresses the activation of H-Ras, N-Ras, and K-Ras. However, it is not known whether these classic Ras proteins are hyperactivated in NF1-null nerve sheath tumors, how they contribute to tumorigenesis, and what signaling pathways mediate their effects. Here we show that H-Ras, N-Ras, and K-Ras are coexpressed with their activators (guanine nucleotide exchange factors) in neurofibromin-null malignant peripheral nerve sheath tumor (MPNST) cells, and that all 3 Ras proteins are activated. Dominant negative (DN) H-Ras, a pan-inhibitor of the classic Ras family, inhibited MPNST proliferation and survival, but not migration. However, NF1-null MPNST cells were variably dependent on individual Ras proteins. In some lines, ablation of H-Ras, N-Ras, and/or K-Ras inhibited mitogenesis. In others, ablation of a single Ras protein had no effect on proliferation; in these lines, ablation of a single Ras protein resulted in compensatory increases in the activation and/or expression of other Ras proteins. Using mass spectrometry-based phosphoproteomics, we identified 7 signaling networks affecting morphology, proliferation, and survival that are regulated by DN H-Ras. Thus, neurofibromin loss activates multiple classic Ras proteins that promote proliferation and survival by regulating several distinct signaling cascades.
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32
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H-ras distribution and signaling in plasma membrane microdomains are regulated by acylation and deacylation events. Mol Cell Biol 2015; 35:1898-914. [PMID: 25776558 DOI: 10.1128/mcb.01398-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 03/10/2015] [Indexed: 12/30/2022] Open
Abstract
H-Ras must adhere to the plasma membrane to be functional. This is accomplished by posttranslational modifications, including palmitoylation, a reversible process whereby H-Ras traffics between the plasma membrane and the Golgi complex. At the plasma membrane, H-Ras has been proposed to occupy distinct sublocations, depending on its activation status: lipid rafts/detergent-resistant membrane fractions when bound to GDP, diffusing to disordered membrane/soluble fractions in response to GTP loading. Herein, we demonstrate that H-Ras sublocalization is dictated by its degree of palmitoylation in a cell type-specific manner. Whereas H-Ras localizes to detergent-resistant membrane fractions in cells with low palmitoylation activity, it locates to soluble membrane fractions in lineages where it is highly palmitoylated. Interestingly, in both cases GTP loading results in H-Ras diffusing away from its original sublocalization. Moreover, tilting the equilibrium between palmitoylation and depalmitoylation processes can substantially alter H-Ras segregation and, subsequently, its biochemical and biological functions. Thus, the palmitoylation/depalmitoylation balance not only regulates H-Ras cycling between endomembranes and the plasma membrane but also serves as a key orchestrator of H-Ras lateral diffusion between different types of plasma membrane and thereby of H-Ras signaling.
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33
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Durgan J, Tao G, Walters MS, Florey O, Schmidt A, Arbelaez V, Rosen N, Crystal RG, Hall A. SOS1 and Ras regulate epithelial tight junction formation in the human airway through EMP1. EMBO Rep 2015; 16:87-96. [PMID: 25394671 PMCID: PMC4304732 DOI: 10.15252/embr.201439218] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 10/23/2014] [Accepted: 10/24/2014] [Indexed: 11/09/2022] Open
Abstract
The human airway is lined with respiratory epithelial cells, which create a critical barrier through the formation of apical tight junctions. To investigate the molecular mechanisms underlying this process, an RNAi screen for guanine nucleotide exchange factors (GEFs) was performed in human bronchial epithelial cells (16HBE). We report that SOS1, acting through the Ras/MEK/ERK pathway, is essential for tight junction formation. Global microarray analysis identifies epithelial membrane protein 1 (EMP1), an integral tetraspan membrane protein, as a major transcriptional target. EMP1 is indispensable for tight junction formation and function in 16HBE cells and in a human airway basal progenitor-like cell line (BCi-NS1.1). Furthermore, EMP1 is significantly downregulated in human lung cancers. Together, these data identify important roles for SOS1/Ras and EMP1 in tight junction assembly during airway morphogenesis.
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Affiliation(s)
- Joanne Durgan
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Guangbo Tao
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Matthew S Walters
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Oliver Florey
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Anja Schmidt
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Vanessa Arbelaez
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Neal Rosen
- Molecular Pharmacology & Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ronald G Crystal
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Alan Hall
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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PP2A-mediated regulation of Ras signaling in G2 is essential for stable quiescence and normal G1 length. Mol Cell 2014; 54:932-945. [PMID: 24857551 DOI: 10.1016/j.molcel.2014.04.023] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 03/04/2014] [Accepted: 04/07/2014] [Indexed: 12/23/2022]
Abstract
Quiescence (G0) allows cycling cells to reversibly cease proliferation. A decision to enter quiescence is suspected of occurring early in G1, before the restriction point (R). Surprisingly, we have identified G2 as an interval during which inhibition of the protein phosphatase PP2A results in failure to exhibit stable quiescence. This effect is accompanied by shortening of the ensuing G1. The PP2A subcomplex required for stable G0 contains the B56γ B subunit. After PP2A inhibition in G2, aberrant overexpression of cyclin E occurs during mitosis and is responsible for overriding quiescence. Strikingly, suppression of Ras signaling re-establishes normal cyclin E levels during M and restores G0. These data point to PP2A-B56γ-driven Ras signaling modulation in G2 as essential for suppressing aberrant cyclin E expression during mitosis and thereby achieving normal G0 control. Thus, G2 is an interval during which the length and growth factor dependence of the next G1 interval are established.
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35
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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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36
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Ras palmitoylation is necessary for N-Ras activation and signal propagation in growth factor signalling. Biochem J 2013; 454:323-32. [PMID: 23758196 DOI: 10.1042/bj20121799] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ras GTPases undergo post-translational modifications that govern their subcellular trafficking and localization. In particular, palmitoylation of the Golgi tags N-Ras and H-Ras for exocytotic transport and residency at the PM (plasma membrane). Following depalmitoylation, PM-Ras redistributes to all subcellular membranes causing an accumulation of palmitate-free Ras at endomembranes, including the Golgi and endoplasmic reticulum. Palmitoylation is unanimously regarded as a critical modification at the crossroads of Ras activity and trafficking control, but its precise relevance to native wild-type Ras function in growth factor signalling is unknown. We show in the present study by use of palmitoylation-deficient N-Ras mutants and via the analysis of palmitate content of agonist-activated GTP-loaded N-Ras that only palmitoylated N-Ras becomes activated by agonists. In line with an essential role of palmitoylation in Ras activation, dominant-negative RasS17N loses its blocking potency if rendered devoid of palmitoylation. Live-cell Ras-GTP imaging shows that N-Ras activation proceeds only at the PM, consistent with activated N-Ras-GTP being palmitoylated. Finally, palmitoylation-deficient N-Ras does not sustain EGF (epidermal growth factor) or serum-elicited mitogenic signalling, confirming that palmitoylation is essential for signal transduction by N-Ras. These findings document that N-Ras activation proceeds at the PM and suggest that depalmitoylation, by removing Ras from the PM, may contribute to the shutdown of Ras signalling.
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37
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The differential effects of wild-type and mutated K-Ras on MST2 signaling are determined by K-Ras activation kinetics. Mol Cell Biol 2013; 33:1859-68. [PMID: 23459937 DOI: 10.1128/mcb.01414-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
K-Ras is frequently mutated in human cancers. Mutant (mt) K-Ras can stimulate both oncogenic transformation and apoptosis through activation of extracellular signal-regulated kinase (ERK) and AKT pathways and the MST2 pathway, respectively. The biological outcome is determined by the balance and cross talk between these pathways. In colorectal cancer (CRC), a K-Ras mutation is negatively correlated with MST2 expression, as mt K-Ras can induce apoptosis by activating the MST2 pathway. However, wild-type (wt) K-Ras can prevent the activation of the MST2 pathway upon growth factor stimulation and enable transformation by mt K-Ras in CRC cells that express MST2. Here we have investigated the mechanism by which wt and mt K-Ras differentially regulate the MST2 pathway and MST2-dependent apoptosis. The ability of K-Ras to activate MST2 and MST2-dependent apoptosis is determined by the differential activation kinetics of mt K-Ras and wt K-Ras. Chronic activation of K-Ras by mutation or overexpression of Ras exchange factors results in the activation of MST2 and LATS1, increased MST2-LATS1 complex formation, and apoptosis. In contrast, transient K-Ras activation upon epidermal growth factor (EGF) stimulation prevents the formation of the MST2-LATS1 complex in an AKT-dependent manner. Our data suggest that the close relationship between Ras prosurvival and proapoptotic signaling is coordinated via the differential regulation of the MST2-LATS1 interaction by transient and chronic stimuli.
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38
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Transforming growth factor beta receptor 2 (TGFBR2) changes sialylation in the microsatellite unstable (MSI) Colorectal cancer cell line HCT116. PLoS One 2013; 8:e57074. [PMID: 23468914 PMCID: PMC3584148 DOI: 10.1371/journal.pone.0057074] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 01/17/2013] [Indexed: 01/09/2023] Open
Abstract
Aberrant glycosylation is a common feature of many malignancies including colorectal cancers (CRCs). About 15% of CRC show the microsatellite instability (MSI) phenotype that is associated with a high frequency of biallelic frameshift mutations in the A10 coding mononucleotide microsatellite of the transforming growth factor beta receptor 2 (TGFBR2) gene. If and how impaired TGFBR2 signaling in MSI CRC cells affects cell surface glycan pattern is largely unexplored. Here, we used the TGFBR2-deficient MSI colon carcinoma cell line HCT116 as a model system. Stable clones conferring doxycycline (dox)-inducible expression of a single copy wildtype TGFBR2 transgene were generated by recombinase-mediated cassette exchange (RMCE). In two independent clones, dox-inducible expression of wildtype TGFBR2 protein and reconstitution of its signaling function was shown. Metabolic labeling experiments using the tritiated sialic acid precursor N-acetyl-D-mannosamine (ManNAc) revealed a significant decline (∼30%) of its incorporation into newly synthesized sialoglycoproteins in a TGFBR2-dependent manner. In particular, we detected a significant decrease of sialylated ß1-integrin upon reconstituted TGFBR2 signaling which did not influence ß1-integrin protein turnover. Notably, TGFBR2 reconstitution did not affect the transcript levels of any of the known human sialyltransferases when examined by real-time RT- PCR analysis. These results suggest that reconstituted TGFBR2 signaling in an isogenic MSI cell line model system can modulate sialylation of cell surface proteins like ß1-integrin. Moreover, our model system will be suitable to uncover the underlying molecular mechanisms of altered MSI tumor glycobiology.
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39
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MASL1 induces erythroid differentiation in human erythropoietin-dependent CD34+ cells through the Raf/MEK/ERK pathway. Blood 2013; 121:3216-27. [PMID: 23327923 DOI: 10.1182/blood-2011-10-385252] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Human erythropoiesis is a dynamic and complex multistep process involving differentiation of early erythroid progenitors into enucleated RBCs. The mechanisms underlying erythropoiesis still remain incompletely understood. We previously demonstrated that erythropoietin-stimulated clone-1, which is selectively expressed in normal human erythroid-lineage cells, shares 99.5% identity with malignant fibrous histiocytoma-amplified sequences with leucine-rich tandem repeats 1 (MASL1). In this study, we hypothesized that the MASL1 gene plays a role in erythroid differentiation, and used a human erythroid cell culture system to explore this concept. MASL1 mRNA and protein expression levels were significantly increased during the erythroid differentiation of CD34(+) cells following erythropoietin (EPO) treatment. Conversely, MASL1 knockdown reduced erythroid differentiation in EPO-treated CD34(+) cells. In addition, MASL1 knockdown interrupted the Raf/MEK/ERK signaling pathway in CD34(+) cells. MASL1 mutant-transfected CD34(+) cells also showed decreased erythroid differentiation. Furthermore, inhibition of the SH3 domain of Son of Sevenless, which is an upstream adapter protein in EPO-induced erythroid differentiation, also reduced MASL1 expression and phosphorylation of Raf/MEK/ERK kinases that consequently reduced erythroid differentiation of EPO-induced CD34(+) cells. Importantly, we also demonstrated that MASL1 interacts physically with Raf1. Taken together, our data provide novel insights into MASL1 regulation of erythropoiesis through the Raf/MEK/ERK pathway.
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40
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Köthe S, Müller JP, Böhmer SA, Tschongov T, Fricke M, Koch S, Thiede C, Requardt RP, Rubio I, Böhmer FD. Features of Ras activation by a mislocalized oncogenic tyrosine kinase: FLT3 ITD signals via K-Ras at the plasma membrane of Acute Myeloid Leukemia cells. J Cell Sci 2013; 126:4746-55. [DOI: 10.1242/jcs.131789] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
FLT3 ITD (FMS-like tyrosine kinase 3 with internal tandem duplication) is an important oncoprotein in Acute Myeloid Leukemia (AML). Owing to its constitutive kinase activity FLT3 ITD accumulates partially at endomembranes, a feature shared with other disease-associated, mutated receptor tyrosine kinases. Since Ras proteins also transit through endomembranes we have investigated the possible existence of an intracellular FLT3 ITD/Ras signaling pathway by comparing Ras signaling of FLT3 ITD with that of wild-type FLT3. Ligand stimulation activated both K- and N-Ras in cells expressing wild-type FLT3. Life-cell Ras-GTP imaging revealed ligand-induced Ras activation at the plasma membrane (PM). FLT3 ITD dependent constitutive activation of K-Ras and N-Ras was also observed primarily at the PM, supporting the view that the PM-resident pool of FLT3 ITD engaged the Ras/Erk pathway in AML cells. Accordingly, specific interference with FLT3 ITD/Ras signaling at the PM using PM-restricted dominant negative K-RasS17N potently inhibited cell proliferation and promoted apoptosis, corroborating that Ras signalling is crucial for FLT3 ITD dependent cell transformation and confirming that FLT3 ITD addresses PM-bound Ras despite its pronounced mislocalization to endomembranes.
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41
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Turk HF, Barhoumi R, Chapkin RS. Alteration of EGFR spatiotemporal dynamics suppresses signal transduction. PLoS One 2012; 7:e39682. [PMID: 22761867 PMCID: PMC3384615 DOI: 10.1371/journal.pone.0039682] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 05/29/2012] [Indexed: 01/18/2023] Open
Abstract
The epidermal growth factor receptor (EGFR), which regulates cell growth and survival, is integral to colon tumorigenesis. Lipid rafts play a role in regulating EGFR signaling, and docosahexaenoic acid (DHA) is known to perturb membrane domain organization through changes in lipid rafts. Therefore, we investigated the mechanistic link between EGFR function and DHA. Membrane incorporation of DHA into immortalized colonocytes altered the lateral organization of EGFR. DHA additionally increased EGFR phosphorylation but paradoxically suppressed downstream signaling. Assessment of the EGFR-Ras-ERK1/2 signaling cascade identified Ras GTP binding as the locus of the DHA-induced disruption of signal transduction. DHA also antagonized EGFR signaling capacity by increasing receptor internalization and degradation. DHA suppressed cell proliferation in an EGFR-dependent manner, but cell proliferation could be partially rescued by expression of constitutively active Ras. Feeding chronically-inflamed, carcinogen-injected C57BL/6 mice a fish oil containing diet enriched in DHA recapitulated the effects on the EGFR signaling axis observed in cell culture and additionally suppressed tumor formation. We conclude that DHA-induced alteration in both the lateral and subcellular localization of EGFR culminates in the suppression of EGFR downstream signal transduction, which has implications for the molecular basis of colon cancer prevention by DHA.
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Affiliation(s)
- Harmony F. Turk
- Program in Integrative Nutrition and Complex Diseases, Texas A & M University, College Station, Texas, United States of America
| | - Rola Barhoumi
- Image Analysis Laboratory, Texas A & M University, College Station, Texas, United States of America
| | - Robert S. Chapkin
- Program in Integrative Nutrition and Complex Diseases, Texas A & M University, College Station, Texas, United States of America
- Center for Environmental and Rural Health, Texas A & M University, College Station, Texas, United States of America
- * E-mail:
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Chan PC, Chen HC. p120RasGAP-mediated activation of c-Src is critical for oncogenic Ras to induce tumor invasion. Cancer Res 2012; 72:2405-15. [PMID: 22411953 DOI: 10.1158/0008-5472.can-11-3078] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ras genes are the most common targets for somatic gain-of-function mutations in human cancers. In this study, we found a high incidence of correlation between Ras oncogenic mutations and c-Src activation in human cancer cells. We showed that oncogenic Ras induces c-Src activation mainly on the Golgi complex and endoplasmic reticulum. Moreover, we identified p120RasGAP as an effector for oncogenic Ras to activate c-Src. The recruitment of p120RasGAP to the Golgi complex by oncogenic Ras facilitated its interaction with c-Src, thereby leading to c-Src activation, and this p120RasGAP-mediated activation of c-Src was important for tumor invasion induced by oncogenic Ras. Collectively, our findings unveil a relationship between oncogenic Ras, p120RasGAP, and c-Src, suggesting a critical role for c-Src in cancers evoked by oncogenic mutations in Ras genes.
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Affiliation(s)
- Po-Chao Chan
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
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43
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Matallanas D, Romano D, Al-Mulla F, O'Neill E, Al-Ali W, Crespo P, Doyle B, Nixon C, Sansom O, Drosten M, Barbacid M, Kolch W. Mutant K-Ras activation of the proapoptotic MST2 pathway is antagonized by wild-type K-Ras. Mol Cell 2011; 44:893-906. [PMID: 22195963 DOI: 10.1016/j.molcel.2011.10.016] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 08/29/2011] [Accepted: 10/10/2011] [Indexed: 01/14/2023]
Abstract
K-Ras mutations are frequent in colorectal cancer (CRC), albeit K-Ras is the only Ras isoform that can elicit apoptosis. Here, we show that mutant K-Ras directly binds to the tumor suppressor RASSF1A to activate the apoptotic MST2-LATS1 pathway. In this pathway LATS1 binds to and sequesters the ubiquitin ligase Mdm2 causing stabilization of the tumor suppressor p53 and apoptosis. However, mutant Ras also stimulates autocrine activation of the EGF receptor (EGFR) which counteracts mutant K-Ras-induced apoptosis. Interestingly, this protection requires the wild-type K-Ras allele, which inhibits the MST2 pathway in part via AKT activation. Confirming the pathophysiological relevance of the molecular findings, we find a negative correlation between K-Ras mutation and MST2 expression in human CRC patients and CRC mouse models. The small number of tumors with co-expression of mutant K-Ras and MST2 has elevated apoptosis rates. Thus, in CRC, mutant K-Ras transformation is supported by the wild-type allele.
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Affiliation(s)
- David Matallanas
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland
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Castellano E, Santos E. Functional specificity of ras isoforms: so similar but so different. Genes Cancer 2011; 2:216-31. [PMID: 21779495 DOI: 10.1177/1947601911408081] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
H-ras, N-ras, and K-ras are canonical ras gene family members frequently activated by point mutation in human cancers and coding for 4 different, highly related protein isoforms (H-Ras, N-Ras, K-Ras4A, and K-Ras4B). Their expression is nearly ubiquitous and broadly conserved across eukaryotic species, although there are quantitative and qualitative differences of expression depending on the tissue and/or developmental stage under consideration. Extensive functional studies have determined during the last quarter century that these Ras gene products are critical components of signaling pathways that control eukaryotic cell proliferation, survival, and differentiation. However, because of their homology and frequent coexpression in various cellular contexts, it remained unclear whether the different Ras proteins play specific or overlapping functional roles in physiological and pathological processes. Initially, their high degree of sequence homology and the observation that all Ras isoforms share common sets of downstream effectors and upstream activators suggested that they were mostly redundant functionally. In contrast, the notion of functional specificity for each of the different Ras isoforms is supported at present by an increasing body of experimental observations, including 1) the fact that different ras isoforms are preferentially mutated in specific types of tumors or developmental disorders; 2) the different transforming potential of transfected ras genes in different cell contexts; 3) the distinct sensitivities exhibited by the various Ras family members for modulation by different GAPs or GEFs; 4) the demonstration that different Ras isoforms follow distinct intracellular processing pathways and localize to different membrane microdomains or subcellular compartments; 5) the different phenotypes displayed by genetically modified animal strains for each of the 3 ras loci; and 6) the specific transcriptional networks controlled by each isoform in different cellular settings.
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Affiliation(s)
- Esther Castellano
- Signal Transduction Laboratory, Cancer Research UK London Research Institute, London, UK
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45
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Abstract
Ever since their discovery as cellular counterparts of viral oncogenes more than 25 years ago, much progress has been made in understanding the complex networks of signal transduction pathways activated by oncogenic Ras mutations in human cancers. The activity of Ras is regulated by nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs), and much emphasis has been put into the biochemical and structural analysis of the Ras/GAP complex. The mechanisms by which GAPs catalyze Ras-GTP hydrolysis have been clarified and revealed that oncogenic Ras mutations confer resistance to GAPs and remain constitutively active. However, it is yet unclear how cells coordinate the large and divergent GAP protein family to promote Ras inactivation and ensure a certain biological response. Different domain arrangements in GAPs to create differential protein-protein and protein-lipid interactions are probably key factors determining the inactivation of the 3 Ras isoforms H-, K-, and N-Ras and their effector pathways. In recent years, in vitro as well as cell- and animal-based studies examining GAP activity, localization, interaction partners, and expression profiles have provided further insights into Ras inactivation and revealed characteristics of several GAPs to exert specific and distinct functions. This review aims to summarize knowledge on the cell biology of RasGAP proteins that potentially contributes to differential regulation of spatiotemporal Ras signaling.
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Affiliation(s)
- Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, Australia
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46
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Arozarena I, Calvo F, Crespo P. Ras, an actor on many stages: posttranslational modifications, localization, and site-specified events. Genes Cancer 2011; 2:182-94. [PMID: 21779492 DOI: 10.1177/1947601911409213] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Among the wealth of information that we have gathered about Ras in the past decade, the introduction of the concept of space in the field has constituted a major revolution that has enabled many pieces of the Ras puzzle to fall into place. In the early days, it was believed that Ras functioned exclusively at the plasma membrane. Today, we know that within the plasma membrane, the 3 Ras isoforms-H-Ras, K-Ras, and N-Ras-occupy different microdomains and that these isoforms are also present and active in endomembranes. We have also discovered that Ras proteins are not statically associated with these localizations; instead, they traffic dynamically between compartments. And we have learned that at these localizations, Ras is under site-specific regulatory mechanisms, distinctively engaging effector pathways and switching on diverse genetic programs to generate different biological responses. All of these processes are possible in great part due to the posttranslational modifications whereby Ras proteins bind to membranes and to regulatory events such as phosphorylation and ubiquitination that Ras is subject to. As such, space and these control mechanisms act in conjunction to endow Ras signals with an enormous signal variability that makes possible its multiple biological roles. These data have established the concept that the Ras signal, instead of being one single, homogeneous entity, results from the integration of multiple, site-specified subsignals, and Ras has become a paradigm of how space can differentially shape signaling.
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Affiliation(s)
- Imanol Arozarena
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC)-IDICAN-Universidad de Cantabria, Departamento de Biología Molecular, Facultad de Medicina, Cantabria, Spain
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Liu B, Yang P, Ye Y, Zhou Y, Li L, Tashiro SI, Onodera S, Ikejima T. Role of ROS in the protective effect of silibinin on sodium nitroprusside-induced apoptosis in rat pheochromocytoma PC12 cells. Free Radic Res 2011; 45:835-47. [PMID: 21568648 DOI: 10.3109/10715762.2011.580343] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Silibinin mostly has been used as hepatoprotectants, but it has other interesting activities, e.g. anti-cancer, cardial protective and brain-protective activities. A previous study demonstrated that silibinin protected amyloid β (Aβ)-induced mouse cognitive disorder by behavioural pharmacological observation. This study assessed the effect of silibinin on sodium nitroprusside (SNP)-treated rat pheochromocytoma PC12 cells. Subsequent morphologic observation, flow cytometric analysis and Western blot analysis indicated that treatment with SNP significantly induced apoptosis in PC12 cells. However, silibinin eliminated the apoptotic effect by reactive oxygen species (ROS) generation, especially hydroxyl free radical. Silibinin-induced autophagy through ROS generation when exerting a protective effect and silibinin-induced autophagy also enhanced the ROS generation since 3-methyladenine (3-MA), a specific autophagy inhibitor, decreased the ROS generation and rapamycin, an autophagy inducer, enhanced the ROS generation. Therefore, there exists a positive feedback loop between autophagy and ROS generation. Autophagy prevented SNP-induced apoptosis, since the addition of 3-MA significantly eliminated the protective effect of silibinin. This protective effect was attributed to the generation of ROS and its two downstream Ras/PI3K/NF-κB and Ras/Raf/MEK/ERK pathways. Both prevented PC12 cells from apoptosis. The PI3K/NF-κB pathway induced autophagy to protect PC12 cells, but the Raf/MEK/ERK pathway directly protected PC12 cells bypassing the autophagic effect.
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Affiliation(s)
- Binbin Liu
- China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang 110016, PR China
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The MEK inhibitor PD184352 enhances BMS-214662-induced apoptosis in CD34+ CML stem/progenitor cells. Leukemia 2011; 25:1159-67. [PMID: 21483442 DOI: 10.1038/leu.2011.67] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cytotoxic farnesyl transferase inhibitor BMS-214662 has been shown to potently induce mitochondrial apoptosis in primitive CD34+ chronic myeloid leukaemia (CML) stem/progenitor cells. Here, to enhance the BMS-214662 apoptotic effect, we further targeted the extracellular signal-regulated kinase (ERK) pathway, downstream of BCR-ABL, by treating CD34+ CML stem/progenitor cells with a highly selective adenosine triphosphate (ATP) non-competitive MEK inhibitor, PD184352. PD184352 increased the apoptotic effect of BMS-214662 in a CML blast crisis cell line, K562, and in primary chronic phase CD34+ CML cells. Compared with BMS-214662, after combination treatment we observed inhibition of ERK phosphorylation, increased Annexin-V levels, caspase-3, -8 and -9 activation and potentiated mitochondrial damage, associated with decreased levels of anti-apoptotic BCL-2 family protein MCL-1. Inhibition of K-RAS function by a dominant-negative mutant resulted in CML cell death and this process was further enhanced by the addition of BMS-214662 and PD184352. Together, these findings suggest that the addition of a MEK inhibitor improves the ability of BMS-214662 to selectively target CML stem/progenitor cells, notoriously insensitive to tyrosine kinase inhibitor treatment and presumed to be responsible for the persistence and relapse of the disease.
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Ranahan WP, Han Z, Smith-Kinnaman W, Nabinger SC, Heller B, Herbert BS, Chan R, Wells CD. The adaptor protein AMOT promotes the proliferation of mammary epithelial cells via the prolonged activation of the extracellular signal-regulated kinases. Cancer Res 2011; 71:2203-11. [PMID: 21285250 DOI: 10.1158/0008-5472.can-10-1995] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The asymmetric organization of epithelial cells is a basic counter to cellular proliferation. However, the mechanisms whereby pro-growth pathways are modulated by intracellular factors that control cell shape are not well understood. This study demonstrates that the adaptor protein Amot, in addition to its established role in regulating cellular asymmetry, also promotes extracellular signal-regulated kinase 1 and 2 (ERK1/2)-dependent proliferation of mammary cells. Specifically, expression of Amot80, but not a mutant lacking its polarity protein interaction domain, enhances ERK1/2-dependent proliferation of MCF7 cells. Further, expression of Amot80 induces nontransformed MCF10A cells to overgrow as disorganized cellular aggregates in Matrigel. Conversely, Amot expression is required for proliferation of breast cancer cells in specific microenvironmental contexts that require ERK1/2 signaling. Thus, Amot is proposed to coordinate the dysregulation of cell polarity with the induction of neoplastic growth in mammary cells.
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Affiliation(s)
- William P Ranahan
- Department of Biochemistry and Molecular Biology, University of Indiana School of Medicine, Indianapolis, Indiana 46202-5122, USA
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50
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Mutations in the c-Kit gene disrupt mitogen-activated protein kinase signaling during tumor development in adenoid cystic carcinoma of the salivary glands. Neoplasia 2011; 12:708-17. [PMID: 20824047 DOI: 10.1593/neo.10356] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 05/31/2010] [Accepted: 06/02/2010] [Indexed: 11/18/2022]
Abstract
The Ras/mitogen-activated protein kinase (MAPK) pathway is considered to be a positive regulator of tumor initiation, progression, and maintenance. This study reports an opposite finding: we have found strong evidence that the MAPK pathway is inhibited in a subset of adenoid cystic carcinomas (ACCs) of the salivary glands. ACC tumors consistently overexpress the receptor tyrosine kinase (RTK) c-Kit, which has been considered a therapeutic target. We performed mutational analysis of the c-Kit gene (KIT in 17 cases of ACC and found that 2 cases of ACC had distinct missense mutations in KIT at both the genomic DNA and messenger RNA levels. These mutations caused G664R and R796G amino acid substitutions in the kinase domains. Surprisingly, the mutations were functionally inactive in cultured cells. We observed a significant reduction of MAPK (ERK1/2) activity in tumor cells, as assessed by immunohistochemistry. We performed further mutational analysis of the downstream effectors in the c-Kit pathway in the genes HRAS, KRAS, NRAS, BRAF, PIK3CA, and PTEN. This analysis revealed that two ACC tumors without KIT mutations had missense mutations in either KRAS or BRAF, causing S17N K-Ras and V590I B-Raf mutants, respectively. Our functional analysis showed that proteins with these mutations were also inactive in cultured cells. This is the first time that MAPK activity from the RTK signaling has been shown to be inhibited by gene mutations during tumor development. Because ACC seems to proliferate despite inactivation of the c-Kit signaling pathway, we suggest that selective inhibition of c-Kit is probably not a suitable treatment strategy for ACC.
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