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Johnson CW, Lin YJ, Reid D, Parker J, Pavlopoulos S, Dischinger P, Graveel C, Aguirre AJ, Steensma M, Haigis KM, Mattos C. Isoform-Specific Destabilization of the Active Site Reveals a Molecular Mechanism of Intrinsic Activation of KRas G13D. Cell Rep 2020; 28:1538-1550.e7. [PMID: 31390567 PMCID: PMC6709685 DOI: 10.1016/j.celrep.2019.07.026] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/28/2019] [Accepted: 07/10/2019] [Indexed: 12/21/2022] Open
Abstract
Ras GTPases are mutated at codons 12, 13, and 61, with different frequencies in KRas, HRas, and NRas and in a cancer-specific manner. The G13D mutant appears in 25% of KRas-driven colorectal cancers, while observed only rarely in HRas or NRas. Structures of Ras G13D in the three isoforms show an open active site, with adjustments to the D13 backbone torsion angles and with disconnected switch regions. KRas G13D has unique features that destabilize the nucleotide-binding pocket. In KRas G13D bound to GDP, A59 is placed in the Mg2+ binding site, as in the HRas-SOS complex. Structure and biochemistry are consistent with an intermediate level of KRas G13D bound to GTP, relative to wild-type and KRas G12D, observed in genetically engineered mouse models. The results explain in part the elevated frequency of the G13D mutant in KRas over the other isoforms of Ras.
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Affiliation(s)
- Christian W Johnson
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Yi-Jang Lin
- Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Derion Reid
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Jillian Parker
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Spiro Pavlopoulos
- Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | | | - Carrie Graveel
- Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Andrew J Aguirre
- Dana-Farber Cancer Institute, Boston, MA 02215, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Kevin M Haigis
- Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Medicine, Harvard Medical School, Boston, MA 02215, USA; Harvard Digestive Disease Center, Boston, MA 02215, USA.
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA.
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Juan J, Muraguchi T, Iezza G, Sears RC, McMahon M. Diminished WNT -> β-catenin -> c-MYC signaling is a barrier for malignant progression of BRAFV600E-induced lung tumors. Genes Dev 2014; 28:561-75. [PMID: 24589553 PMCID: PMC3967046 DOI: 10.1101/gad.233627.113] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Oncogene-induced senescence (OIS) is proposed as a cellular defense mechanism that restrains malignant progression of oncogene-expressing, initiated tumor cells. Consistent with this, expression of BRAF(V600E) in the mouse lung epithelium elicits benign tumors that fail to progress to cancer due to an apparent senescence-like proliferative arrest. Here we demonstrate that nuclear β-catenin → c-MYC signaling is essential for early stage proliferation of BRAF(V600E)-induced lung tumors and is inactivated in the subsequent senescence-like state. Furthermore, either β-catenin silencing or pharmacological blockade of Porcupine, an acyl-transferase essential for WNT ligand secretion and activity, significantly inhibited BRAF(V600E)-initiated lung tumorigenesis. Conversely, sustained activity of β-catenin or c-MYC significantly enhanced BRAF(V600E)-induced lung tumorigenesis and rescued the anti-tumor effects of Porcupine blockade. These data indicate that early stage BRAF(V600E)-induced lung tumors are WNT-dependent and suggest that inactivation of WNT → β-catenin → c-MYC signaling is a trigger for the senescence-like proliferative arrest that constrains the expansion and malignant progression of BRAF(V600E)-initiated lung tumors. Moreover, these data further suggest that the trigger for OIS in initiated BRAF(V600E)-expressing lung tumor cells is not simply a surfeit of signals from oncogenic BRAF but an insufficiency of WNT → β-catenin → c-MYC signaling. These data have implications for understanding how genetic abnormalities cooperate to initiate and promote lung carcinogenesis.
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Affiliation(s)
- Joseph Juan
- Helen Diller Family Comprehensive Cancer Center
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González-Sánchez E, Martín-Caballero J, Flores JM, Hernández-Losa J, Cortés J, Mares R, Barbacid M, Recio JA. Lkb1 loss promotes tumor progression of BRAF(V600E)-induced lung adenomas. PLoS One 2013; 8:e66933. [PMID: 23825589 PMCID: PMC3692542 DOI: 10.1371/journal.pone.0066933] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/11/2013] [Indexed: 11/18/2022] Open
Abstract
Aberrant activation of MAP kinase signaling pathway and loss of tumor suppressor LKB1 have been implicated in lung cancer development and progression. Although oncogenic KRAS mutations are frequent, BRAF mutations (BRAFV600E) are found in 3% of human non-small cell lung cancers. Contrary to KRAS mutant tumors, BRAFV600E-induced tumors are benign adenomas that fail to progess. Interestingly, loss of tumor supressor LKB1 coexists with KRAS oncogenic mutations and synergizes in tumor formation and progression, however, its cooperation with BRAFV600E oncogene is unknown. Our results describe a lung cell population in neonates mice where expression of BRAFV600E leads to lung adenoma development. Importantly, expression of BRAFV600E concomitant with the loss of only a single-copy of Lkb1, overcomes senencence–like features of BRAFV600E-mutant adenomas leading malignization to carcinomas. These results posit LKB1 haploinsufficiency as a risk factor for tumor progression of BRAFV600E mutated lung adenomas in human cancer patients.
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Affiliation(s)
- Elena González-Sánchez
- Animal Models and Cancer Laboratory, Anatomy Pathology Department, Vall d’Hebron Institut of Research-Autonomous University of Barcelona (VHIR-UAB) Barcelona, Barcelona, Spain
| | - Juan Martín-Caballero
- Animal Laboratory Unit, Biomedical Research Park of Barcelona-Prbb, Barcelona, Spain
| | - Juana María Flores
- Surgery and Medicine Department, Veterinary School, Universidad Complutense de Madrid, Madrid, Spain
| | | | - Ma Ángeles Montero
- Histopathology Department, Royal Brompton and Harefield NHS Trust, London, United Kingdom
| | - Javier Cortés
- Medical Oncology Department, Vall d’Hebron Institut of Oncology (VHIO)-Vall d’Hebron Hospital, Barcelona, Spain
| | - Roso Mares
- Anatomy Pathology Department, Vall d’Hebron Hospital, Barcelona, Spain
| | - Mariano Barbacid
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas, Madrid, Madrid, Spain
| | - Juan A. Recio
- Animal Models and Cancer Laboratory, Anatomy Pathology Department, Vall d’Hebron Institut of Research-Autonomous University of Barcelona (VHIR-UAB) Barcelona, Barcelona, Spain
- * E-mail:
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Sheu JJC, Guan B, Tsai FJ, Hsiao EYT, Chen CM, Seruca R, Wang TL, Shih IM. Mutant BRAF induces DNA strand breaks, activates DNA damage response pathway, and up-regulates glucose transporter-1 in nontransformed epithelial cells. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:1179-1188. [PMID: 22227015 PMCID: PMC4429179 DOI: 10.1016/j.ajpath.2011.11.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 10/17/2011] [Accepted: 11/14/2011] [Indexed: 02/03/2023]
Abstract
Although the oncogenic functions of activating BRAF mutations have been clearly demonstrated in human cancer, their roles in nontransformed epithelial cells remain largely unclear. Investigating the cellular response to the expression of mutant BRAF in nontransformed epithelial cells is fundamental to the understanding of the roles of BRAF in cancer pathogenesis. In this study, we used two nontransformed cyst108 and RK3E epithelial cell lines as models in which to compare the phenotypes of cells expressing BRAF(WT) and BRAF(V600E). We found that transfection of the BRAF(V600E), but not the BRAF(WT), expression vector suppressed cellular proliferation and induced apoptosis in both cell types. BRAF(V600E) generated reactive oxygen species, induced DNA double-strand breaks, and caused subsequent DNA damage response as evidenced by an increased number of pCHK2 and γH2AX nuclear foci as well as the up-regulation of pCHK2, p53, and p21. Because BRAF and KRAS (alias Ki-ras) mutations have been correlated with GLUT1 up-regulation, which encodes glucose transporter-1, we demonstrated here that expression of BRAF(V600E), but not BRAF(WT), was sufficient to up-regulate GLUT1. Taken together, our findings provide new insights into mutant BRAF-induced oncogenic stress that is manifested by DNA damage and growth arrest by activating the pCHK2-p53-p21 pathway in nontransformed cells, while it also confers tumor-promoting phenotypes such as the up-regulation of GLUT1 that contributes to enhanced glucose metabolism that characterizes tumor cells.
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Affiliation(s)
- Jim Jinn-Chyuan Sheu
- Human Genetic Center, China Medical University Hospital, Taichung, Taiwan; School of Chinese Medicine, China Medical University, Taichung, Taiwan.
| | - Bin Guan
- Departments of Pathology, Oncology, Gynecology and Obstetrics, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Fuu-Jen Tsai
- Human Genetic Center, China Medical University Hospital, Taichung, Taiwan
| | - Erin Yi-Ting Hsiao
- Human Genetic Center, China Medical University Hospital, Taichung, Taiwan
| | - Chih-Mei Chen
- Human Genetic Center, China Medical University Hospital, Taichung, Taiwan
| | - Raquel Seruca
- Institute of Molecular Pathology and Immunology, The University of Porto, Porto, Portugal
| | - Tian-Li Wang
- Departments of Pathology, Oncology, Gynecology and Obstetrics, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Ie-Ming Shih
- Departments of Pathology, Oncology, Gynecology and Obstetrics, Johns Hopkins Medical Institutions, Baltimore, Maryland.
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Charles RP, Iezza G, Amendola E, Dankort D, McMahon M. Mutationally activated BRAF(V600E) elicits papillary thyroid cancer in the adult mouse. Cancer Res 2011; 71:3863-71. [PMID: 21512141 DOI: 10.1158/0008-5472.can-10-4463] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mutated BRAF is detected in approximately 45% of papillary thyroid carcinomas (PTC). To model PTC, we bred mice with adult-onset, thyrocyte-specific expression of BRAF(V600E). One month following BRAF(V600E) expression, mice displayed increased thyroid size, widespread alterations in thyroid architecture, and dramatic hypothyroidism. Over 1 year, without any deliberate manipulation of tumor suppressor genes, all mice developed PTC displaying nuclear atypia and marker expression characteristic of the human disease. Pharmacologic inhibition of MEK1/2 led to decreased thyroid size, restoration of thyroid form and function, and inhibition of tumorigenesis. Mice with BRAF(V600E)-induced PTC will provide an excellent system to study thyroid tumor initiation and progression and the evaluation of inhibitors of oncogenic BRAF signaling.
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Affiliation(s)
- Roch-Philippe Charles
- UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, California, USA
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Hinoue T, Weisenberger DJ, Pan F, Campan M, Kim M, Young J, Whitehall VL, Leggett BA, Laird PW. Analysis of the association between CIMP and BRAF in colorectal cancer by DNA methylation profiling. PLoS One 2009; 4:e8357. [PMID: 20027224 PMCID: PMC2791229 DOI: 10.1371/journal.pone.0008357] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2009] [Accepted: 11/20/2009] [Indexed: 12/15/2022] Open
Abstract
A CpG island methylator phenotype (CIMP) is displayed by a distinct subset of colorectal cancers with a high frequency of DNA hypermethylation in a specific group of CpG islands. Recent studies have shown that an activating mutation of BRAF (BRAFV600E) is tightly associated with CIMP, raising the question of whether BRAFV600E plays a causal role in the development of CIMP or whether CIMP provides a favorable environment for the acquisition of BRAFV600E. We employed Illumina GoldenGate DNA methylation technology, which interrogates 1,505 CpG sites in 807 different genes, to further study this association. We first examined whether expression of BRAFV600E causes DNA hypermethylation by stably expressing BRAFV600E in the CIMP-negative, BRAF wild-type COLO 320DM colorectal cancer cell line. We determined 100 CIMP-associated CpG sites and examined changes in DNA methylation in eight stably transfected clones over multiple passages. We found that BRAFV600E is not sufficient to induce CIMP in our system. Secondly, considering the alternative possibility, we identified genes whose DNA hypermethylation was closely linked to BRAFV600E and CIMP in 235 primary colorectal tumors. Interestingly, genes that showed the most significant link include those that mediate various signaling pathways implicated in colorectal tumorigenesis, such as BMP3 and BMP6 (BMP signaling), EPHA3, KIT, and FLT1 (receptor tyrosine kinases) and SMO (Hedgehog signaling). Furthermore, we identified CIMP-dependent DNA hypermethylation of IGFBP7, which has been shown to mediate BRAFV600E-induced cellular senescence and apoptosis. Promoter DNA hypermethylation of IGFBP7 was associated with silencing of the gene. CIMP-specific inactivation of BRAFV600E-induced senescence and apoptosis pathways by IGFBP7 DNA hypermethylation might create a favorable context for the acquisition of BRAFV600E in CIMP+ colorectal cancer. Our data will be useful for future investigations toward understanding CIMP in colorectal cancer and gaining insights into the role of aberrant DNA hypermethylation in colorectal tumorigenesis.
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Affiliation(s)
- Toshinori Hinoue
- USC Epigenome Center, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- Department of Surgery and Department of Biochemistry and Molecular Biology, USC/Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Daniel J. Weisenberger
- USC Epigenome Center, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Fei Pan
- USC Epigenome Center, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Mihaela Campan
- Department of Surgery and Department of Biochemistry and Molecular Biology, USC/Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Myungjin Kim
- Department of Surgery and Department of Biochemistry and Molecular Biology, USC/Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Joanne Young
- Familial Cancer Laboratory, Queensland Institute of Medical Research, Herston, Queensland, Australia
- University of Queensland School of Medicine, Herston, Queensland, Australia
| | - Vicki L. Whitehall
- Conjoint Gastroenterology Laboratory, Clinical Research Centre, Royal Brisbane and Women's Hospital Research Foundation, Herston, Queensland, Australia
| | - Barbara A. Leggett
- Conjoint Gastroenterology Laboratory, Clinical Research Centre, Royal Brisbane and Women's Hospital Research Foundation, Herston, Queensland, Australia
| | - Peter W. Laird
- USC Epigenome Center, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- Department of Surgery and Department of Biochemistry and Molecular Biology, USC/Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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