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Clavaín L, Fernández-Pisonero I, Movilla N, Lorenzo-Martín LF, Nieto B, Abad A, García-Navas R, Llorente-González C, Sánchez-Martín M, Vicente-Manzanares M, Santos E, Alarcón B, García-Aznar JM, Dosil M, Bustelo XR. Characterization of mutant versions of the R-RAS2/TC21 GTPase found in tumors. Oncogene 2023; 42:389-405. [PMID: 36476833 PMCID: PMC9883167 DOI: 10.1038/s41388-022-02563-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022]
Abstract
The R-RAS2 GTP hydrolase (GTPase) (also known as TC21) has been traditionally considered quite similar to classical RAS proteins at the regulatory and signaling levels. Recently, a long-tail hotspot mutation targeting the R-RAS2/TC21 Gln72 residue (Q72L) was identified as a potent oncogenic driver. Additional point mutations were also found in other tumors at low frequencies. Despite this, little information is available regarding the transforming role of these mutant versions and their relevance for the tumorigenic properties of already-transformed cancer cells. Here, we report that many of the RRAS2 mutations found in human cancers are highly transforming when expressed in immortalized cell lines. Moreover, the expression of endogenous R-RAS2Q72L is important for maintaining optimal levels of PI3K and ERK activities as well as for the adhesion, invasiveness, proliferation, and mitochondrial respiration of ovarian and breast cancer cell lines. Endogenous R-RAS2Q72L also regulates gene expression programs linked to both cell adhesion and inflammatory/immune-related responses. Endogenous R-RAS2Q72L is also quite relevant for the in vivo tumorigenic activity of these cells. This dependency is observed even though these cancer cell lines bear concurrent gain-of-function mutations in genes encoding RAS signaling elements. Finally, we show that endogenous R-RAS2, unlike the case of classical RAS proteins, specifically localizes in focal adhesions. Collectively, these results indicate that gain-of-function mutations of R-RAS2/TC21 play roles in tumor initiation and maintenance that are not fully redundant with those regulated by classical RAS oncoproteins.
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Affiliation(s)
- Laura Clavaín
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC and University of Salamanca, 37007 Salamanca, Spain
| | - Isabel Fernández-Pisonero
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC and University of Salamanca, 37007 Salamanca, Spain
| | - Nieves Movilla
- grid.11205.370000 0001 2152 8769Aragon Institute of Engineering Research, Department of Mechanical Engineering, University of Zaragoza, 50018 Zaragoza, Spain
| | - L. Francisco Lorenzo-Martín
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC and University of Salamanca, 37007 Salamanca, Spain
| | - Blanca Nieto
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain
| | - Antonio Abad
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC and University of Salamanca, 37007 Salamanca, Spain
| | - Rósula García-Navas
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC and University of Salamanca, 37007 Salamanca, Spain
| | - Clara Llorente-González
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain
| | - Manuel Sánchez-Martín
- grid.11762.330000 0001 2180 1817Transgenesis Facility and Nucleus Platform for Research Services, University of Salamanca, 37007 Salamanca, Spain
| | - Miguel Vicente-Manzanares
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain
| | - Eugenio Santos
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC and University of Salamanca, 37007 Salamanca, Spain
| | - Balbino Alarcón
- grid.5515.40000000119578126Centro de Biología Molecular Severo Ochoa, CSIC and Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - José M. García-Aznar
- grid.11205.370000 0001 2152 8769Aragon Institute of Engineering Research, Department of Mechanical Engineering, University of Zaragoza, 50018 Zaragoza, Spain
| | - Mercedes Dosil
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC and University of Salamanca, 37007 Salamanca, Spain
| | - Xosé R. Bustelo
- grid.11762.330000 0001 2180 1817Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Instituto de Biología Molecular y Celular del Cáncer, CSIC and University of Salamanca, 37007 Salamanca, Spain ,grid.11762.330000 0001 2180 1817Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC and University of Salamanca, 37007 Salamanca, Spain
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A hotspot mutation targeting the R-RAS2 GTPase acts as a potent oncogenic driver in a wide spectrum of tumors. Cell Rep 2022; 38:110522. [PMID: 35294890 DOI: 10.1016/j.celrep.2022.110522] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 12/22/2021] [Accepted: 02/20/2022] [Indexed: 12/20/2022] Open
Abstract
A missense change in RRAS2 (Gln72 to Leu), analogous to the Gln61-to-Leu mutation of RAS oncoproteins, has been identified as a long-tail hotspot mutation in cancer and Noonan syndrome. However, the relevance of this mutation for in vivo tumorigenesis remains understudied. Here we show, using an inducible knockin mouse model, that R-Ras2Q72L triggers rapid development of a wide spectrum of tumors when somatically expressed in adult tissues. These tumors show limited overlap with those originated by classical Ras oncogenes. R-Ras2Q72L-driven tumors can be classified into different subtypes according to therapeutic susceptibility. Importantly, the most relevant R-Ras2Q72L-driven tumors are dependent on mTORC1 but independent of phosphatidylinositol 3-kinase-, MEK-, and Ral guanosine diphosphate (GDP) dissociation stimulator. This pharmacological vulnerability is due to the extensive rewiring by R-Ras2Q72L of pathways that orthogonally stimulate mTORC1 signaling. These findings demonstrate that RRAS2Q72L is a bona fide oncogenic driver and unveil therapeutic strategies for patients with cancer and Noonan syndrome bearing RRAS2 mutations.
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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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Nakhaei-Rad S, Haghighi F, Nouri P, Rezaei Adariani S, Lissy J, Kazemein Jasemi NS, Dvorsky R, Ahmadian MR. Structural fingerprints, interactions, and signaling networks of RAS family proteins beyond RAS isoforms. Crit Rev Biochem Mol Biol 2018; 53:130-156. [PMID: 29457927 DOI: 10.1080/10409238.2018.1431605] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Saeideh Nakhaei-Rad
- a Institute of Biochemistry and Molecular Biology II, Medical Faculty , Heinrich-Heine University , Düsseldorf , Germany
| | - Fereshteh Haghighi
- a Institute of Biochemistry and Molecular Biology II, Medical Faculty , Heinrich-Heine University , Düsseldorf , Germany
| | - Parivash Nouri
- a Institute of Biochemistry and Molecular Biology II, Medical Faculty , Heinrich-Heine University , Düsseldorf , Germany
| | - Soheila Rezaei Adariani
- a Institute of Biochemistry and Molecular Biology II, Medical Faculty , Heinrich-Heine University , Düsseldorf , Germany
| | - Jana Lissy
- a Institute of Biochemistry and Molecular Biology II, Medical Faculty , Heinrich-Heine University , Düsseldorf , Germany
| | - Neda S Kazemein Jasemi
- a Institute of Biochemistry and Molecular Biology II, Medical Faculty , Heinrich-Heine University , Düsseldorf , Germany
| | - Radovan Dvorsky
- a Institute of Biochemistry and Molecular Biology II, Medical Faculty , Heinrich-Heine University , Düsseldorf , Germany
| | - Mohammad Reza Ahmadian
- a Institute of Biochemistry and Molecular Biology II, Medical Faculty , Heinrich-Heine University , Düsseldorf , Germany
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Nakhaeizadeh H, Amin E, Nakhaei-Rad S, Dvorsky R, Ahmadian MR. The RAS-Effector Interface: Isoform-Specific Differences in the Effector Binding Regions. PLoS One 2016; 11:e0167145. [PMID: 27936046 PMCID: PMC5147862 DOI: 10.1371/journal.pone.0167145] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 11/09/2016] [Indexed: 12/31/2022] Open
Abstract
RAS effectors specifically interact with the GTP-bound form of RAS in response to extracellular signals and link them to downstream signaling pathways. The molecular nature of effector interaction by RAS is well-studied but yet still incompletely understood in a comprehensive and systematic way. Here, structure-function relationships in the interaction between different RAS proteins and various effectors were investigated in detail by combining our in vitro data with in silico data. Equilibrium dissociation constants were determined for the binding of HRAS, KRAS, NRAS, RRAS1 and RRAS2 to both the RAS binding (RB) domain of CRAF and PI3Kα, and the RAS association (RA) domain of RASSF5, RALGDS and PLCε, respectively, using fluorescence polarization. An interaction matrix, constructed on the basis of available crystal structures, allowed identification of hotspots as critical determinants for RAS-effector interaction. New insights provided by this study are the dissection of the identified hotspots in five distinct regions (R1 to R5) in spite of high sequence variability not only between, but also within, RB/RA domain-containing effectors proteins. Finally, we propose that intermolecular β-sheet interaction in R1 is a central recognition region while R3 may determine specific contacts of RAS versus RRAS isoforms with effectors.
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Affiliation(s)
- Hossein Nakhaeizadeh
- Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine University, Düsseldorf, Germany
| | - Ehsan Amin
- Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine University, Düsseldorf, Germany
| | - Saeideh Nakhaei-Rad
- Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine University, Düsseldorf, Germany
| | - Radovan Dvorsky
- Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine University, Düsseldorf, Germany
| | - Mohammad Reza Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine University, Düsseldorf, Germany
- * E-mail:
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6
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Huff LP, DeCristo MJ, Cox AD. Effector recruitment method to study spatially regulated activation of Ras and Rho GTPases. Methods Mol Biol 2014; 1120:263-83. [PMID: 24470032 DOI: 10.1007/978-1-62703-791-4_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Ras and Rho family GTPases control a wide variety of cellular processes, and the signaling downstream of these GTPases is influenced by their subcellular localization when activated. Since only a minority of total cellular GTPases is active, observation of the total subcellular distribution of GTPases does not reveal where active GTPases are localized. In this chapter, we describe the use of effector recruitment assays to monitor the subcellular localization of active Ras and Rho family GTPases. The recruitment assay relies on preferential binding of downstream effectors to active GTPases versus inactive GTPases. Tagging the GTPase-binding-domain (GBD) of a downstream effector with a fluorescent protein produces a probe that is recruited to compartments where GTPases are active. We describe an example of a recruitment assay using the GBD of PAK1 to monitor Rac1 activity and explain how the assay can be expanded to determine the subcellular localization of activation of other GTPases.
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Affiliation(s)
- Lauren P Huff
- Department of Radiation Oncology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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7
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Liao W, Jordaan G, Coriaty N, Sharma S. Amplification of B cell receptor-Erk signaling by Rasgrf-1 overexpression in chronic lymphocytic leukemia. Leuk Lymphoma 2014; 55:2907-16. [PMID: 24597981 DOI: 10.3109/10428194.2014.898759] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Rasgrf-1 is a guanine exchange factor (GEF) that catalyzes the exchange of GDP for GTP. In a RNA microarray analysis of chronic lymphocytic leukemia (CLL) specimens (n = 5), this gene was found to be overexpressed in CLL as compared to normal peripheral blood mononuclear cell (PBMC) CD19 + B cells (n = 3). CLL specimens (n = 29) expressed Rasgrf-1 RNA at levels 5-300-fold higher as compared to normal B cells. CLL specimens expressed a 75 kDa isoform that was smaller than the expected full-length protein (140 kDa) and the truncated variant had higher GEF activity. Knockdown of Rasgrf-1 in CLL specimens inhibited active GTP-bound Ras and the Ras/Erk/mitogen-activated protein kinase (MAPK) pathway. Rasgrf-1 was phosphorylated and activated by B cell receptor (BCR) signaling that increased its GEF function, and this phosphorylation was blocked by Src and Bruton's tyrosine kinase (BTK) inhibitors. Rasgrf-1 is a novel GEF protein that has a role in BCR signaling and its overexpression further activates the Ras/Erk/MAPK pathway in CLL specimens.
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Affiliation(s)
- Wei Liao
- Division of Hematology-Oncology, Greater Los Angeles VA Healthcare Center, UCLA School of Medicine , Los Angeles, CA , USA
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8
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Larive RM, Abad A, Cardaba CM, Hernández T, Cañamero M, de Álava E, Santos E, Alarcón B, Bustelo XR. The Ras-like protein R-Ras2/TC21 is important for proper mammary gland development. Mol Biol Cell 2012; 23:2373-87. [PMID: 22535521 PMCID: PMC3374755 DOI: 10.1091/mbc.e12-01-0060] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
R-Ras2/TC21 is a GTPase with high sequence and signaling similarity with Ras subfamily members. Although it has been extensively studied using overexpression studies in cell lines, its physiological role remains poorly characterized. Here we used RRas2-knockout mice expressing β-galactosidase under the regulation of the endogenous RRas2 promoter to investigate the function of this GTPase in vivo. Despite its expression in tissues critical for organismal viability, RRas2(-/-) mice show no major alterations in viability, growth rates, cardiovascular parameters, or fertility. By contrast, they display a marked and specific defect in the development of the mammary gland during puberty. In the absence of R-Ras2/TC21, this gland forms reduced numbers of terminal end buds (TEBs) and ductal branches, leading to a temporal delay in the extension and arborization of the gland tree in mammary fat pads. This phenotype is linked to cell-autonomous proliferative defects of epithelial cells present in TEBs. These cells also show reduced Erk activation but wild type-like levels of phosphorylated Akt. Using compound RRas2-, HRas-, and NRas-knockout mice, we demonstrate that these GTPases act in a nonsynergistic and nonadditive manner during this morphogenic process.
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Affiliation(s)
- Romain M Larive
- Centro de Investigación del Cáncer, Consejo Superior de Investigaciones Científicas-University of Salamanca, E37007 Salamanca, Spain
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9
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Crespo P, Calvo F, Sanz-Moreno V. Ras and Rho GTPases on the move: The RasGRF connection. BIOARCHITECTURE 2011; 1:200-204. [PMID: 22069515 DOI: 10.4161/bioa.1.4.17774] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 08/10/2011] [Accepted: 08/10/2011] [Indexed: 12/29/2022]
Abstract
Metastasis involves tumor cells moving through tissues and crossing tissue boundaries, which requires cell migration, remodeling of cell-to-cell contacts and interactions with the extracellular matrix. Individual tumor cells move in three-dimensional environments with either a rounded "ameboid" or an elongated "mesenchymal" morphology. These two modes of movement are tightly regulated by Rho family GTPases: elongated movement requires activation of Rac1, whereas rounded movement engages specific Cdc42 and Rho signaling pathways. It has been known for some time that events unfolding downstream of Ras GTPases are also involved in regulating multiple aspects of cell migration and invasion. More recently, RasGRF2-a Ras activator-has been identified as a suppressor of rounded movement, by inhibiting the activation of Cdc42, independently of its capacity to activate Ras. Here, we discuss how Rho and Ras signals can either cooperate or oppose each other in the regulation of cell migration and invasion.
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Affiliation(s)
- Piero Crespo
- Instituto de Biomedicina y Biotecnologıa de Cantabria (IBBTEC); Consejo Superior de Investigaciones Cientıficas (CSIC)-IDICAN-Universidad de Cantabria; Departamento de Biologıa Molecular; Facultad de Medicina; Santander, Cantabria Spain
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10
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Calvo F, Sanz-Moreno V, Agudo-Ibáñez L, Wallberg F, Sahai E, Marshall CJ, Crespo P. RasGRF suppresses Cdc42-mediated tumour cell movement, cytoskeletal dynamics and transformation. Nat Cell Biol 2011; 13:819-26. [PMID: 21685891 DOI: 10.1038/ncb2271] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 04/28/2011] [Indexed: 01/03/2023]
Abstract
Individual tumour cells move in three-dimensional environments with either a rounded or an elongated 'mesenchymal' morphology. These two modes of movement are tightly regulated by Rho family GTPases: elongated movement requires activation of Rac1, whereas rounded/amoeboid movement engages specific Cdc42 and Rho signalling pathways. In siRNA screens targeting the genes encoding guanine nucleotide exchange factors (GEFs), we found that the Ras GEF RasGRF2 regulates conversion between elongated- and rounded-type movement. RasGRF2 suppresses rounded movement by inhibiting the activation of Cdc42 independently of its capacity to activate Ras. RasGRF2 and RasGRF1 directly bind to Cdc42, outcompeting Cdc42 GEFs, thereby preventing Cdc42 activation. By this mechanism, RasGRFs regulate other Cdc42-mediated cellular processes such as the formation of actin spikes, transformation and invasion in vitro and in vivo. These results demonstrate a role for RasGRF GEFs as negative regulators of Cdc42 activation.
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Affiliation(s)
- Fernando Calvo
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas-IDICAN-Universidad de Cantabria, Departamento de Biología Molecular, Facultad de Medicina, Santander, 39011, Cantabria, Spain
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Genome-wide functional screen identifies a compendium of genes affecting sensitivity to tamoxifen. Proc Natl Acad Sci U S A 2011; 109:2730-5. [PMID: 21482774 DOI: 10.1073/pnas.1018872108] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Therapies that target estrogen signaling have made a very considerable contribution to reducing mortality from breast cancer. However, resistance to tamoxifen remains a major clinical problem. Here we have used a genome-wide functional profiling approach to identify multiple genes that confer resistance or sensitivity to tamoxifen. Combining whole-genome shRNA screening with massively parallel sequencing, we have profiled the impact of more than 56,670 RNA interference reagents targeting 16,487 genes on the cellular response to tamoxifen. This screen, along with subsequent validation experiments, identifies a compendium of genes whose silencing causes tamoxifen resistance (including BAP1, CLPP, GPRC5D, NAE1, NF1, NIPBL, NSD1, RAD21, RARG, SMC3, and UBA3) and also a set of genes whose silencing causes sensitivity to this endocrine agent (C10orf72, C15orf55/NUT, EDF1, ING5, KRAS, NOC3L, PPP1R15B, RRAS2, TMPRSS2, and TPM4). Multiple individual genes, including NF1, a regulator of RAS signaling, also correlate with clinical outcome after tamoxifen treatment.
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12
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Fernández-Medarde A, Santos E. The RasGrf family of mammalian guanine nucleotide exchange factors. Biochim Biophys Acta Rev Cancer 2010; 1815:170-88. [PMID: 21111786 DOI: 10.1016/j.bbcan.2010.11.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Accepted: 11/14/2010] [Indexed: 12/31/2022]
Abstract
RasGrf1 and RasGrf2 are highly homologous mammalian guanine nucleotide exchange factors which are able to activate specific Ras or Rho GTPases. The RasGrf genes are preferentially expressed in the central nervous system, although specific expression of either locus may also occur elsewhere. RasGrf1 is a paternally-expressed, imprinted gene that is expressed only after birth. In contrast, RasGrf2 is not imprinted and shows a wider expression pattern. A variety of isoforms for both genes are also detectable in different cellular contexts. The RasGrf proteins exhibit modular structures composed by multiple domains including CDC25H and DHPH motifs responsible for promoting GDP/GTP exchange, respectively, on Ras or Rho GTPase targets. The various domains are essential to define their intrinsic exchanger activity and to modulate the specificity of their functional activity so as to connect different upstream signals to various downstream targets and cellular responses. Despite their homology, RasGrf1 and RasGrf2 display differing target specificities and non overlapping functional roles in a variety of signaling contexts related to cell growth and differentiation as well as neuronal excitability and response or synaptic plasticity. Whereas both RasGrfs are activatable by glutamate receptors, G-protein-coupled receptors or changes in intracellular calcium concentration, only RasGrf1 is reported to be activated by LPA, cAMP, or agonist-activated Trk and cannabinoid receptors. Analysis of various knockout mice strains has uncovered a specific functional contribution of RasGrf1 in processes of memory and learning, photoreception, control of post-natal growth and body size and pancreatic β-cell function and glucose homeostasis. For RasGrf2, specific roles in lymphocyte proliferation, T-cell signaling responses and lymphomagenesis have been described.
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