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Sabbir MG, Swanson M, Albensi BC. Loss of cholinergic receptor muscarinic 1 impairs cortical mitochondrial structure and function: implications in Alzheimer's disease. Front Cell Dev Biol 2023; 11:1158604. [PMID: 37274741 PMCID: PMC10233041 DOI: 10.3389/fcell.2023.1158604] [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: 02/04/2023] [Accepted: 05/04/2023] [Indexed: 06/06/2023] Open
Abstract
Introduction: Cholinergic Receptor Muscarinic 1 (CHRM1) is a G protein-coupled acetylcholine (ACh) receptor predominantly expressed in the cerebral cortex. In a retrospective postmortem brain tissues-based study, we demonstrated that severely (≥50% decrease) reduced CHRM1 proteins in the temporal cortex of Alzheimer's patients significantly correlated with poor patient outcomes. The G protein-mediated CHRM1 signal transduction cannot sufficiently explain the mechanistic link between cortical CHRM1 loss and the appearance of hallmark Alzheimer's pathophysiologies, particularly mitochondrial structural and functional abnormalities. Therefore, the objective of this study was to analyze the molecular, ultrastructural, and functional properties of cortical mitochondria using CHRM1 knockout (Chrm1-/-) and wild-type mice to identify mitochondrial abnormalities. Methods: Isolated and enriched cortical mitochondrial fractions derived from wild-type and Chrm1-/- mice were assessed for respiratory deficits (oxygen consumption) following the addition of different substrates. The supramolecular assembly of mitochondrial oxidative phosphorylation (OXPHOS)-associated protein complexes (complex I-V) and cortical mitochondrial ultrastructure were investigated by blue native polyacrylamide gel electrophoresis and transmission electron microscopy (TEM), respectively. A cocktail of antibodies, specific to Ndufb8, Sdhb, Uqcrc2, Mtco1, and Atp5a proteins representing different subunits of complexes I-V, respectively was used to characterize different OXPHOS-associated protein complexes. Results: Loss of Chrm1 led to a significant reduction in cortical mitochondrial respiration (oxygen consumption) concomitantly associated with reduced oligomerization of ATP synthase (complex V) and supramolecular assembly of complexes I-IV (Respirasome). Overexpression of Chrm1 in transformed cells (lacking native Chrm1) significantly increased complex V oligomerization and respirasome assembly leading to enhanced respiration. TEM analysis revealed that Chrm1 loss led to mitochondrial ultrastructural defects and alteration in the tinctorial properties of cortical neurons causing a significant increase in the abundance of dark cortical neurons (Chrm1-/- 85% versus wild-type 2%). Discussion: Our findings indicate a hitherto unknown effect of Chrm1 deletion in cortical neurons affecting mitochondrial function by altering multiple interdependent factors including ATP synthase oligomerization, respirasome assembly, and mitochondrial ultrastructure. The appearance of dark neurons in Chrm1-/- cortices implies potentially enhanced glutamatergic signaling in pyramidal neurons under Chrm1 loss condition. The findings provide novel mechanistic insights into Chrm1 loss with the appearance of mitochondrial pathophysiological deficits in Alzheimer's disease.
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Affiliation(s)
- Mohammad Golam Sabbir
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
- Alzo Biosciences Inc, SanDiego, CA, United States
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
- Barry & Judy Silverman College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL, United States
| | - Mamiko Swanson
- Alzo Biosciences Inc, SanDiego, CA, United States
- Barry & Judy Silverman College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL, United States
| | - Benedict C. Albensi
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
- Barry & Judy Silverman College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL, United States
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada
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Pan J, Li D, Fan X, Cheng J, Jin S, Chen P, Lin H, Li Y. Aberrant DNA Methylation Patterns of Deleted in Liver Cancer 1 Isoforms in Hepatocellular Carcinoma. DNA Cell Biol 2023; 42:140-150. [PMID: 36917700 DOI: 10.1089/dna.2022.0384] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Hepatocellular carcinoma (HCC), a common primary liver cancer, is the third leading cause of death worldwide. DNA methylation changes are common in HCC and have been studied to be associated with hepatocarcinogenesis. In our study, we used the MassARRAY® EpiTYPER technology to investigate the methylation differences of deleted in liver cancer 1 (DLC1) (isoform 1 and 3) promoter between HCC tissues and corresponding adjacent noncancerous tissues and the association between methylation levels and clinicopathological features. In addition, the modified CRISPR-Cas9 system and the DNA methyltransferase inhibitor (DNMTi) were utilized to explore the functional correlation of epigenetic modifications and DLC1 gene regulation. The methylation levels of the DLC1 isoforms in HCC samples were found significantly lower than those in the adjacent noncancerous tissues (all p < 0.0001). Also, we found that the expression of DLC1 could be bidirectionally regulated by the modified CRISPR-Cas9 system and the DNMTi. Moreover, the hypomethylation of DLC1 in HCC samples was connected with the presence of satellite lesions (p = 0.0305) and incomplete tumor capsule (p = 0.0204). Receiver operator characteristic curve analysis demonstrated that the methylation levels of DLC1 could be applied to discriminate HCC patients (area under the curve = 0.728, p < 0.0001). The hypomethylation status was a key regulatory mechanism of DLC1 expression and might serve as a potential biomarker for HCC.
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Affiliation(s)
- Junhai Pan
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Duguang Li
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiaoxiao Fan
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- State Key Laboratory of Modern Optical Instrumentations, Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Hangzhou, China
| | - Jiaxi Cheng
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Shengxi Jin
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Peng Chen
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Hui Lin
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
- Zhejiang Engineering Research Center of Cognitive Healthcare, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou,China
| | - Yirun Li
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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Hinsenkamp I, Köhler JP, Flächsenhaar C, Hitkova I, Meessen SE, Gaiser T, Wieland T, Weiss C, Röcken C, Mowat M, Quante M, Taxauer K, Mejias-Luque R, Gerhard M, Vogelmann R, Meindl-Beinker N, Ebert M, Burgermeister E. Functional antagonism between CagA and DLC1 in gastric cancer. Cell Death Dis 2022; 8:358. [PMID: 35963849 PMCID: PMC9376073 DOI: 10.1038/s41420-022-01134-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 11/09/2022]
Abstract
Helicobacter (H.) pylori-induced gastritis is a risk factor for gastric cancer (GC). Deleted-in-liver-cancer-1 (DLC1/ARHGAP7) inhibits RHOA, a downstream mediator of virulence factor cytotoxin-A (CagA) signalling and driver of consensus-molecular-subtype-2 diffuse GC. DLC1 located to enterochromaffin-like and MIST1+ stem/chief cells in the stomach. DLC1+ cells were reduced in H. pylori gastritis and GC, and in mice infected with H. pylori. DLC1 positivity inversely correlated with tumour progression in patients. GC cells retained an N-terminal truncation variant DLC1v4 in contrast to full-length DLC1v1 in non-neoplastic tissues. H. pylori and CagA downregulated DLC1v1/4 promoter activities. DLC1v1/4 inhibited cell migration and counteracted CagA-driven stress phenotypes enforcing focal adhesion. CagA and DLC1 interacted via their N- and C-terminal domains, proposing that DLC1 protects against H. pylori by neutralising CagA. H. pylori-induced DLC1 loss is an early molecular event, which makes it a potential marker or target for subtype-aware cancer prevention or therapy.
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Affiliation(s)
- Isabel Hinsenkamp
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Jan P Köhler
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Christoph Flächsenhaar
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Institute of Pathology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Ivana Hitkova
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Sabine Eberhart Meessen
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Timo Gaiser
- Institute of Pathology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Thomas Wieland
- Experimental Pharmacology, European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Christel Weiss
- Department of Medical Statistics and Biomathematics, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Christoph Röcken
- Institute of Pathology, Christian Albrechts University Kiel, Kiel, Germany
| | - Michael Mowat
- CancerCare Manitoba Research Institute, Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB, Canada
| | - Michael Quante
- Department of Medicine II, Gastroenterology, Hepatology, Endocrinology, and Infectious Diseases, Faculty of Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Karin Taxauer
- Institute for Med. Microbiology, Immunology and Hygiene, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Raquel Mejias-Luque
- Institute for Med. Microbiology, Immunology and Hygiene, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Markus Gerhard
- Institute for Med. Microbiology, Immunology and Hygiene, School of Medicine, Technical University of Munich (TUM), Munich, Germany
| | - Roger Vogelmann
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Nadja Meindl-Beinker
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Matthias Ebert
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,DKFZ-Hector Institute at the University Medical Center, Mannheim, Germany.,Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Clinical Cooperation Unit Healthy Metabolism, Center of Preventive Medicine and Digital Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Elke Burgermeister
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
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Thymic Epithelial Neoplasms: Focusing on the Epigenetic Alterations. Int J Mol Sci 2022; 23:ijms23074045. [PMID: 35409405 PMCID: PMC8999627 DOI: 10.3390/ijms23074045] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/02/2022] [Accepted: 04/04/2022] [Indexed: 02/08/2023] Open
Abstract
Thymic Epithelial Neoplasms (TENs) represent the most common tumors of the thymus gland. Epigenetic alterations are generally involved in initiation and progression of various cancer entities. However, little is known about the role of epigenetic modifications in TENs. In order to identify relevant studies, a literature review was conducted using the MEDLINE and LIVIVO databases. The search terms thymoma, thymic carcinoma, thymic epithelial neoplasm, epigenetics, DNA methylation, HDAC and miRNA were employed and we were able to identify forty studies focused on TENs and published between 1997 and 2021. Aberrant epigenetic alterations seem to be involved in the tumorigenesis of thymomas and thymic carcinomas, with numerous studies reporting on non-coding RNA clusters and altered gene methylation as possible biomarkers in different types of TENs. Interestingly, Histone Deacetylase Inhibitors have shown potent antitumor effects in clinical trials, thus possibly representing effective epigenetic therapeutic agents in TENs. Additional studies in larger patient cohorts are, nevertheless, needed to verify the clinical utility and safety of novel epigenetic agents in the treatment of patients with TENs.
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Wang D, Qian X, Sanchez-Solana B, Tripathi BK, Durkin ME, Lowy DR. Cancer-Associated Point Mutations in the DLC1 Tumor Suppressor and Other Rho-GAPs Occur Frequently and Are Associated with Decreased Function. Cancer Res 2020; 80:3568-3579. [PMID: 32606003 DOI: 10.1158/0008-5472.can-19-3984] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/25/2020] [Accepted: 06/26/2020] [Indexed: 02/06/2023]
Abstract
In advanced cancer, the RHOA GTPase is often active together with reduced expression of genes encoding Rho-specific GTPase-accelerating proteins (Rho-GAP), which negatively regulate RHOA and related GTPases. Here we used the The Cancer Genome Atlas dataset to examine 12 tumor types (including colon, breast, prostate, pancreas, lung adenocarcinoma, and squamous cell carcinoma) for the frequency of codon mutations of 10 Rho-GAP and experimentally tested biochemical and biological consequences for cancer-associated mutants that arose in the DLC1 tumor suppressor gene. DLC1 was the Rho-GAP gene mutated most frequently, with 5%-8% of tumors in five of the tumor types evaluated having DLC1 missense mutations. Furthermore, 20%-26% of the tumors in four of these five tumor types harbored missense mutations in at least one of the 10 Rho-GAPs. Experimental analysis of the DLC1 mutants indicated 7 of 9 mutants whose lesions were located in the Rho-GAP domain were deficient for Rho-GAP activity and for suppressing cell migration and anchorage-independent growth. Analysis of a DLC1 linker region mutant and a START domain mutant showed each was deficient for suppressing migration and growth in agar, but their Rho-GAP activity was similar to that of wild-type DLC1. Compared with the wild-type, the linker region mutant bound 14-3-3 proteins less efficiently, while the START domain mutant displayed reduced binding to Caveolin-1. Thus, mutation of Rho-GAP genes occurs frequently in some cancer types and the majority of cancer-associated DLC1 mutants evaluated were deficient biologically, with various mechanisms contributing to their reduced activity. SIGNIFICANCE: These findings indicate that point mutation of Rho-GAP genes is unexpectedly frequent in several cancer types, with DLC1 mutants exhibiting reduced function by various mechanisms.
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Affiliation(s)
- Dunrui Wang
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institute of Health, Bethesda, Maryland
| | - Xiaolan Qian
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institute of Health, Bethesda, Maryland
| | - Beatriz Sanchez-Solana
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institute of Health, Bethesda, Maryland
| | - Brajendra K Tripathi
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institute of Health, Bethesda, Maryland
| | - Marian E Durkin
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institute of Health, Bethesda, Maryland
| | - Douglas R Lowy
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institute of Health, Bethesda, Maryland.
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6
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Zhang Y, Li G. A tumor suppressor DLC1: The functions and signal pathways. J Cell Physiol 2019; 235:4999-5007. [DOI: 10.1002/jcp.29402] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 09/27/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Yang Zhang
- Shandong Provincial Key Laboratory of Animal Resistant, School of Life SciencesShandong Normal UniversityJinan China
| | - Guorong Li
- Shandong Provincial Key Laboratory of Animal Resistant, School of Life SciencesShandong Normal UniversityJinan China
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7
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Bustelo XR. RHO GTPases in cancer: known facts, open questions, and therapeutic challenges. Biochem Soc Trans 2018; 46:741-760. [PMID: 29871878 PMCID: PMC7615761 DOI: 10.1042/bst20170531] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/17/2018] [Accepted: 05/03/2018] [Indexed: 02/06/2023]
Abstract
RHO GTPases have been traditionally associated with protumorigenic functions. While this paradigm is still valid in many cases, recent data have unexpectedly revealed that RHO proteins can also play tumor suppressor roles. RHO signaling elements can also promote both pro- and antitumorigenic effects using GTPase-independent mechanisms, thus giving an extra layer of complexity to the role of these proteins in cancer. Consistent with these variegated roles, both gain- and loss-of-function mutations in RHO pathway genes have been found in cancer patients. Collectively, these observations challenge long-held functional archetypes for RHO proteins in both normal and cancer cells. In this review, I will summarize these data and discuss new questions arising from them such as the functional and clinical relevance of the mutations found in patients, the mechanistic orchestration of those antagonistic functions in tumors, and the pros and cons that these results represent for the development of RHO-based anticancer drugs.
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Affiliation(s)
- Xosé R Bustelo
- Centro de Investigación del Cáncer, Instituto de Biología Molecular y Celular del Cáncer, and Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Consejo Superior de Investigaciones Científicas (CSIC)-University of Salamanca, 37007 Salamanca, Spain
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8
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Modular transcriptional repertoire and MicroRNA target analyses characterize genomic dysregulation in the thymus of Down syndrome infants. Oncotarget 2016; 7:7497-533. [PMID: 26848775 PMCID: PMC4884935 DOI: 10.18632/oncotarget.7120] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/23/2016] [Indexed: 12/25/2022] Open
Abstract
Trisomy 21-driven transcriptional alterations in human thymus were characterized through gene coexpression network (GCN) and miRNA-target analyses. We used whole thymic tissue--obtained at heart surgery from Down syndrome (DS) and karyotipically normal subjects (CT)--and a network-based approach for GCN analysis that allows the identification of modular transcriptional repertoires (communities) and the interactions between all the system's constituents through community detection. Changes in the degree of connections observed for hierarchically important hubs/genes in CT and DS networks corresponded to community changes. Distinct communities of highly interconnected genes were topologically identified in these networks. The role of miRNAs in modulating the expression of highly connected genes in CT and DS was revealed through miRNA-target analysis. Trisomy 21 gene dysregulation in thymus may be depicted as the breakdown and altered reorganization of transcriptional modules. Leading networks acting in normal or disease states were identified. CT networks would depict the "canonical" way of thymus functioning. Conversely, DS networks represent a "non-canonical" way, i.e., thymic tissue adaptation under trisomy 21 genomic dysregulation. This adaptation is probably driven by epigenetic mechanisms acting at chromatin level and through the miRNA control of transcriptional programs involving the networks' high-hierarchy genes.
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Rodriguez-Hernandez I, Cantelli G, Bruce F, Sanz-Moreno V. Rho, ROCK and actomyosin contractility in metastasis as drug targets. F1000Res 2016; 5. [PMID: 27158478 PMCID: PMC4856114 DOI: 10.12688/f1000research.7909.1] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/26/2016] [Indexed: 12/17/2022] Open
Abstract
Metastasis is the spread of cancer cells around the body and the cause of the majority of cancer deaths. Metastasis is a very complex process in which cancer cells need to dramatically modify their cytoskeleton and cope with different environments to successfully colonize a secondary organ. In this review, we discuss recent findings pointing at Rho-ROCK or actomyosin force (or both) as major drivers of many of the steps required for metastatic success. We propose that these are important drug targets that need to be considered in the clinic to palliate metastatic disease.
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Affiliation(s)
- Irene Rodriguez-Hernandez
- Tumour Plasticity Laboratory, Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London, SE1 1UL, UK
| | - Gaia Cantelli
- Tumour Plasticity Laboratory, Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London, SE1 1UL, UK
| | - Fanshawe Bruce
- Tumour Plasticity Laboratory, Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London, SE1 1UL, UK.,Department of Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, St. Thomas Hospital, King's College London, London, SE1 7EH, UK
| | - Victoria Sanz-Moreno
- Tumour Plasticity Laboratory, Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London, SE1 1UL, UK
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Sabbir MG, Dillon R, Mowat MRA. Dlc1 interaction with non-muscle myosin heavy chain II-A (Myh9) and Rac1 activation. Biol Open 2016; 5:452-60. [PMID: 26977077 PMCID: PMC4890663 DOI: 10.1242/bio.015859] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/23/2016] [Indexed: 01/30/2023] Open
Abstract
The Deleted in liver cancer 1 (Dlc1) gene codes for a Rho GTPase-activating protein that also acts as a tumour suppressor gene. Several studies have consistently found that overexpression leads to excessive cell elongation, cytoskeleton changes and subsequent cell death. However, none of these studies have been able to satisfactorily explain the Dlc1-induced cell morphological phenotypes and the function of the different Dlc1 isoforms. Therefore, we have studied the interacting proteins associated with the three major Dlc1 transcriptional isoforms using a mass spectrometric approach in Dlc1 overexpressing cells. We have found and validated novel interacting partners in constitutive Dlc1-expressing cells. Our study has shown that Dlc1 interacts with non-muscle myosin heavy chain II-A (Myh9), plectin and spectrin proteins in different multiprotein complexes. Overexpression of Dlc1 led to increased phosphorylation of Myh9 protein and activation of Rac1 GTPase. These data support a role for Dlc1 in induced cell elongation morphology and provide some molecular targets for further analysis of this phenotype.
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Affiliation(s)
- Mohammad G Sabbir
- Research Institute of Oncology and Hematology, CancerCare Manitoba, Winnipeg, Manitoba R3E 0V9, Canada
| | - Rachelle Dillon
- Research Institute of Oncology and Hematology, CancerCare Manitoba, Winnipeg, Manitoba R3E 0V9, Canada
| | - Michael R A Mowat
- Research Institute of Oncology and Hematology, CancerCare Manitoba, Winnipeg, Manitoba R3E 0V9, Canada Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, R3E 0J9, Canada
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Marx A, Porubsky S, Belharazem D, Saruhan-Direskeneli G, Schalke B, Ströbel P, Weis CA. Thymoma related myasthenia gravis in humans and potential animal models. Exp Neurol 2015; 270:55-65. [PMID: 25700911 DOI: 10.1016/j.expneurol.2015.02.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/16/2015] [Accepted: 02/04/2015] [Indexed: 02/06/2023]
Abstract
Thymoma-associated Myasthenia gravis (TAMG) is one of the anti-acetylcholine receptor MG (AChR-MG) subtypes. The clinico-pathological features of TAMG and its pathogenesis are described here in comparison with pathogenetic models suggested for the more common non-thymoma AChR-MG subtypes, early onset MG and late onset MG. Emphasis is put on the role of abnormal intratumorous T cell selection and activation, lack of intratumorous myoid cells and regulatory T cells as well as deficient expression of the autoimmune regulator (AIRE) by neoplastic thymic epithelial cells. We review spontaneous and genetically engineered thymoma models in a spectrum of animals and the extensive clinical and immunological overlap between canine, feline and human TAMG. Finally, limitations and perspectives of the transplantation of human and murine thymoma tissue into nude mice, as potential models for TAMG, are addressed.
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Affiliation(s)
- Alexander Marx
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 13, D-68167 Mannheim, Germany.
| | - Stefan Porubsky
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 13, D-68167 Mannheim, Germany
| | - Djeda Belharazem
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 13, D-68167 Mannheim, Germany
| | - Güher Saruhan-Direskeneli
- Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Capa 34093, Istanbul, Turkey.
| | - Berthold Schalke
- Department of Neurology, Bezirkskrankenhaus, University of Regensburg, D-93042 Regensburg, Germany.
| | - Philipp Ströbel
- Institute of Pathology, University of Göttingen, Robert-Koch-Str. 40, D-37075 Göttingen, Germany.
| | - Cleo-Aron Weis
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 13, D-68167 Mannheim, Germany.
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Abstract
During metastasis, cancer cells disseminate to other parts of the body by entering the bloodstream in a process that is called intravasation. They then extravasate at metastatic sites by attaching to endothelial cells that line blood vessels and crossing the vessel walls of tissues or organs. This Review describes how cancer cells cross the endothelial barrier during extravasation and how different receptors, signalling pathways and circulating cells such as leukocytes and platelets contribute to this process. Identification of the mechanisms that underlie cancer cell extravasation could lead to the development of new therapies to reduce metastasis.
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Affiliation(s)
- Nicolas Reymond
- 1] Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK. [2] Centre de Recherche de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique (CNRS) - UMR5237, 1919 Route de Mende, 34293 Montpellier, Cedex 5, France. [3]
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13
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Qian X, Durkin ME, Wang D, Tripathi BK, Olson L, Yang XY, Vass WC, Popescu NC, Lowy DR. Inactivation of the Dlc1 gene cooperates with downregulation of p15INK4b and p16Ink4a, leading to neoplastic transformation and poor prognosis in human cancer. Cancer Res 2012; 72:5900-11. [PMID: 23010077 DOI: 10.1158/0008-5472.can-12-2368] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The tumor suppressor gene deleted in liver cancer-1 (DLC1), which encodes a protein with strong RhoGAP (GTPase activating protein) activity and weak Cdc42GAP activity, is inactivated in various human malignancies. Following Dlc1 inactivation, mouse embryo fibroblasts (MEF) with a conditional Dlc1 knockout allele reproducibly underwent neoplastic transformation. In addition to inactivation of Dlc1 and increased activity of Rho and Cdc42, transformation depended on the subsequent decreased expression of the Cdk4/6 inhibitors p15(Ink4b) and p16(Ink4a) together with increased expression and activation of Cdk4/6. The level of expression of these cell-cycle regulatory genes was relevant to human tumors with low DLC1 expression. Analysis of publicly available annotated datasets of lung and colon cancer with gene expression microarray profiles indicated that, in pairwise comparisons, low DLC1 expression occurred frequently together (P < 0.01) with downregulation of p15(Ink4b) or p16(Ink4a) or upregulation of CDK4 or CDK6. In addition, an unfavorable prognosis (P < 0.05) was associated with low DLC1 and low p15(Ink4b) in lung cancer and colon cancer, low DLC1 and low p16(Ink4a) in lung cancer, low DLC1 and high CDK4 in lung cancer, and low DLC1 and high CDK6 in colon cancer. Thus, several genes and biochemical activities collaborate with the inactivation of DLC1 to give rise to cell transformation in MEFs, and the identified genes are relevant to human tumors with low DLC1 expression.
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Affiliation(s)
- Xiaolan Qian
- Laboratories of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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