1
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Loss of RanGAP1 drives chromosome instability and rapid tumorigenesis of osteosarcoma. Dev Cell 2023; 58:192-210.e11. [PMID: 36696903 DOI: 10.1016/j.devcel.2022.12.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 09/27/2022] [Accepted: 12/29/2022] [Indexed: 01/26/2023]
Abstract
Chromothripsis is a catastrophic event of chromosomal instability that involves intensive fragmentation and rearrangements within localized chromosomal regions. However, its cause remains unclear. Here, we show that reduction and inactivation of Ran GTPase-activating protein 1 (RanGAP1) commonly occur in human osteosarcoma, which is associated with a high rate of chromothripsis. In rapidly expanding mouse osteoprogenitors, RanGAP1 deficiency causes chromothripsis in chr1q, instant inactivation of Rb1 and degradation of p53, consequent failure in DNA damage repair, and ultrafast osteosarcoma tumorigenesis. During mitosis, RanGAP1 anchors to the kinetochore, where it recruits PP1-γ to counteract the activity of the spindle-assembly checkpoint (SAC) and prevents TOP2A degradation, thus safeguarding chromatid decatenation. Loss of RanGAP1 causes SAC hyperactivation and chromatid decatenation failure. These findings demonstrate that RanGAP1 maintains mitotic chromosome integrity and that RanGAP1 loss drives tumorigenesis through its direct effects on SAC and decatenation and secondary effects on DNA damage surveillance.
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2
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Ni K, Hong L. Current Progress and Perspectives of CDC20 in Female Reproductive Cancers. Curr Mol Med 2023; 23:193-199. [PMID: 35319365 DOI: 10.2174/1573405618666220321130102] [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] [Received: 09/13/2021] [Revised: 01/30/2022] [Accepted: 01/31/2022] [Indexed: 02/08/2023]
Abstract
The cancers of the cervix, endometrium, ovary, and breast are great threats to women's health. Cancer is characterized by the uncontrolled proliferation of cells and deregulated cell cycle progression is one of the main causes of malignancy. Agents targeting cell cycle regulators may have potential anti-tumor effects. CDC20 (cell division cycle 20 homologue) is a co-activator of the anaphase-promoting complex/cyclosome (APC/C) and thus acts as a mitotic regulator. In addition, CDC20 serves as a subunit of the mitotic checkpoint complex (MCC) whose function is to inhibit APC/C. Recently, higher expression of CDC20 has been reported in these cancers and was closely associated with their clinicopathological parameters, indicating CDC20 a potential target for cancer treatment that is worth further study. In the present review, we summarized current progress and put forward perspectives of CDC20 in female reproductive cancers.
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Affiliation(s)
- Ke Ni
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Li Hong
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan 430060, China
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3
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Ren S, Gaykalova DA, Guo T, Favorov AV, Fertig EJ, Tamayo P, Callejas-Valera JL, Allevato M, Gilardi M, Santos J, Fukusumi T, Sakai A, Ando M, Sadat S, Liu C, Xu G, Fisch KM, Wang Z, Molinolo AA, Gutkind JS, Ideker T, Koch WM, Califano JA. HPV E2, E4, E5 drive alternative carcinogenic pathways in HPV positive cancers. Oncogene 2020; 39:6327-6339. [PMID: 32848210 PMCID: PMC7529583 DOI: 10.1038/s41388-020-01431-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 07/19/2020] [Accepted: 08/13/2020] [Indexed: 12/26/2022]
Abstract
The dominant paradigm for HPV carcinogenesis includes integration into the host genome followed by expression of E6 and E7 (E6/E7). We explored an alternative carcinogenic pathway characterized by episomal E2, E4, and E5 (E2/E4/E5) expression. Half of HPV positive cervical and pharyngeal cancers comprised a subtype with increase in expression of E2/E4/E5, as well as association with lack of integration into the host genome. Models of the E2/E4/E5 carcinogenesis show p53 dependent enhanced proliferation in vitro, as well as increased susceptibility to induction of cancer in vivo. Whole genomic expression analysis of the E2/E4/E5 pharyngeal cancer subtype is defined by activation of the fibroblast growth factor receptor (FGFR) pathway and this subtype is susceptible to combination FGFR and mTOR inhibition, with implications for targeted therapy.
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Affiliation(s)
- Shuling Ren
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA.,Department of Otolaryngology-Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Daria A Gaykalova
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Theresa Guo
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Alexander V Favorov
- Division of Oncology Biostatistics, Department of Oncology, Johns Hopkins Medical Institutions, Baltimore, MD, USA.,Laboratory of Systems Biology and Computational Genetics, Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Elana J Fertig
- Division of Oncology Biostatistics, Department of Oncology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Pablo Tamayo
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Juan Luis Callejas-Valera
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA.,Cancer Biology and Immunotherapies group, Sanford Research, Sioux Falls, SD, USA
| | - Mike Allevato
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Mara Gilardi
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Jessica Santos
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Takahito Fukusumi
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Akihiro Sakai
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Mizuo Ando
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Sayed Sadat
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Chao Liu
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Guorong Xu
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Kathleen M Fisch
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Zhiyong Wang
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Alfredo A Molinolo
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - J Silvio Gutkind
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Trey Ideker
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Wayne M Koch
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Joseph A Califano
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA. .,Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of California San Diego, La Jolla, CA, USA.
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4
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Zhao Q, Li H, Zhu L, Hu S, Xi X, Liu Y, Liu J, Zhong T. Bioinformatics analysis shows that TOP2A functions as a key candidate gene in the progression of cervical cancer. Biomed Rep 2020; 13:21. [PMID: 32765860 PMCID: PMC7403841 DOI: 10.3892/br.2020.1328] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 03/13/2020] [Indexed: 02/06/2023] Open
Abstract
Cervical cancer (CC) is one of the most prevalent types of cancer affecting females worldwide. However, the molecular mechanisms underlying the development and progression of CC remains to be elucidated. Taking the high incidence and mortality rates amongst women into consideration, the identification of novel biomarkers to prevent CC is of great significance and required to improve diagnosis. Using three raw microarray datasets from the Gene Expression Omnibus database, 188 differentially expressed genes (DEGs) were identified. Gene Ontology and pathway analyses were performed on the DEGs. Through protein-protein interaction network construction and module analysis, eight hub genes [cell division cycle 6, cyclin-dependent kinase 1 (CDK1), cell division control protein 45, budding uninhibited by benzimidazoles 1 (BUB1), DNA topoisomerase II α (TOP2A) and minichromosome maintenance complex component 4, CCNB2 and CCNB1] were identified, but only TOP2A was considered a prognostic factor in survival analysis. There were strong positive correlations between TOP2A and BUB1 (P<0.0001, rs=0.635), CDK1 (P<0.0001, rs=0.511), centromere protein F (CENPF) (P<0.0001, rs=0.677), Rac GTPase activating protein 1 (RACGAP1) (P<0.0001, rs=0.612), F-box protein 5 (FBXO5) (P<0.0001, rs=0.585) and BUB1 mitotic checkpoint serine/threonine kinase B (BUB1B) (P<0.0001, rs=0.584). Additionally, BUB1, CDK1, CENPF, RACGAP1, FBXO5 and BUB1B are all potentially suitable candidate targets for the diagnosis and treatment of CC. In conclusion, the present study identified TOP2A as a potential tumor oncogene and a biomarker for the prognosis of CC.
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Affiliation(s)
- Qinfei Zhao
- Department of Laboratory Medicine, First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi 341000, P.R. China
| | - Huaying Li
- Department of Clinical College, Xiangtan Medicine and Health Vocational College, Xiangtan, Hunan 411104, P.R. China
| | - Longyu Zhu
- Department of Oncology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 50011, P.R. China
| | - Suping Hu
- Department of Emergency, First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi 341000, P.R. China
| | - Xuxiang Xi
- Department of Laboratory Medicine, First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi 341000, P.R. China
| | - Yanmei Liu
- Department of Laboratory Medicine, First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi 341000, P.R. China
| | - Jianfeng Liu
- Department of Laboratory Medicine, First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi 341000, P.R. China
| | - Tianyu Zhong
- Department of Laboratory Medicine, First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi 341000, P.R. China.,Precision Medicine Center, First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi 341000, P.R. China
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5
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Curtis NL, Ruda GF, Brennan P, Bolanos-Garcia VM. Deregulation of Chromosome Segregation and Cancer. ANNUAL REVIEW OF CANCER BIOLOGY 2020. [DOI: 10.1146/annurev-cancerbio-030419-033541] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The mitotic spindle assembly checkpoint (SAC) is an intricate cell signaling system that ensures the high fidelity and timely segregation of chromosomes during cell division. Mistakes in this process can lead to the loss, gain, or rearrangement of the genetic material. Gross chromosomal aberrations are usually lethal but can cause birth and development defects as well as cancer. Despite advances in the identification of SAC protein components, important details of the interactions underpinning chromosome segregation regulation remain to be established. This review discusses the current understanding of the function, structure, mode of regulation, and dynamics of the assembly and disassembly of SAC subcomplexes, which ultimately safeguard the accurate transmission of a stable genome to descendants. We also discuss how diverse oncoviruses take control of human cell division by exploiting the SAC and the potential of this signaling circuitry as a pool of drug targets to develop effective cancer therapies.
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Affiliation(s)
- Natalie L. Curtis
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
| | - Gian Filippo Ruda
- Target Discovery Institute and Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Paul Brennan
- Target Discovery Institute and Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Victor M. Bolanos-Garcia
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
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6
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Villota C, Varas-Godoy M, Jeldes E, Campos A, Villegas J, Borgna V, Burzio LO, Burzio VA. HPV-18 E2 protein downregulates antisense noncoding mitochondrial RNA-2, delaying replicative senescence of human keratinocytes. Aging (Albany NY) 2019; 11:33-47. [PMID: 30595560 PMCID: PMC6339806 DOI: 10.18632/aging.101711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 12/06/2018] [Indexed: 12/12/2022]
Abstract
Human and mouse cells display a differential expression pattern of a family of mitochondrial noncoding RNAs (ncmtRNAs), according to proliferative status. Normal proliferating and cancer cells express a sense ncmtRNA (SncmtRNA), which seems to be required for cell proliferation, and two antisense transcripts referred to as ASncmtRNA-1 and -2. Remarkably however, the ASncmtRNAs are downregulated in human and mouse cancer cells, including HeLa and SiHa cells, transformed with HPV-18 and HPV-16, respectively. HPV E2 protein is considered a tumor suppressor in the context of high-risk HPV-induced transformation and therefore, to explore the mechanisms involved in the downregulation of ASncmtRNAs during tumorigenesis, we studied human foreskin keratinocytes (HFK) transduced with lentiviral-encoded HPV-18 E2. Transduced cells displayed a significantly extended replicative lifespan of up to 23 population doublings, compared to 8 in control cells, together with downregulation of the ASncmtRNAs. At 26 population doublings, cells transduced with E2 were arrested at G2/M, together with downregulation of E2 and SncmtRNA and upregulation of ASncmtRNA-2. Our results suggest a role for high-risk HPV E2 protein in cellular immortalization. Additionally, we propose a new cellular phenotype according to the expression of the SncmtRNA and the ASncmtRNAs.
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Affiliation(s)
- Claudio Villota
- Fundación Ciencia & Vida, Santiago, Chile.,Andes Biotechnologies SpA, Santiago, Chile.,Departamento de Ciencias Químicas y Biológicas, Facultad de Salud, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Manuel Varas-Godoy
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de los Andes, Santiago, Chile
| | - Emanuel Jeldes
- Fundación Ciencia & Vida, Santiago, Chile.,Andes Biotechnologies SpA, Santiago, Chile.,Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - América Campos
- Fundación Ciencia & Vida, Santiago, Chile.,Andes Biotechnologies SpA, Santiago, Chile.,Laboratorio de Comunicaciones Celulares (CEMC) Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Jaime Villegas
- Fundación Ciencia & Vida, Santiago, Chile.,Andes Biotechnologies SpA, Santiago, Chile.,Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Vincenzo Borgna
- Fundación Ciencia & Vida, Santiago, Chile.,Andes Biotechnologies SpA, Santiago, Chile.,Faculty of Medical Sciences, Universidad de Santiago de Chile, Santiago, Chile
| | - Luis O Burzio
- Fundación Ciencia & Vida, Santiago, Chile.,Andes Biotechnologies SpA, Santiago, Chile.,Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Verónica A Burzio
- Fundación Ciencia & Vida, Santiago, Chile.,Andes Biotechnologies SpA, Santiago, Chile.,Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
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7
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Wang L, Wang J, Jin Y, Zheng J, Yang Y, Xi X. Downregulation of Mad2 and BubR1 increase the malignant potential and nocodazole resistance by compromising spindle assembly checkpoint signaling pathway in cervical carcinogenesis. J Obstet Gynaecol Res 2019; 45:2407-2418. [PMID: 31523901 DOI: 10.1111/jog.14120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 08/25/2019] [Indexed: 12/21/2022]
Abstract
AIM To explore the involvement of Mad2 and BubR1 in cervical carcinogenesis. METHODS The expressions of Mad2 and BubR1 in tissues of high-grade squamous intraepithelial lesions (HSIL), low-grade squamous intraepithelial lesions (LSIL) and chronic cervicitis were analyzed immunohistochemistrily and compared with those of p16INK4A . PEGFP-Mad2 and pEGFP-BubR1 were transfected into SiHa cells to overexpress Mad2 and BubR1 and Si-RNAs to knockdown. Cell viability was measured by cell counting kit-8 (CCK-8) assay. Migration and invasion capabilities were detected by Transwell. Propidium iodide staining with flow cytometry was used for cell cycle analysis and apoptosis was detected using Annexin V/7-AAD staining after nocodazole treatment. RESULTS The expression of Mad2 was significantly lower in HSIL than those in chronic cervicitis and LSIL, however, the expression of BubR1 showed no significant differences. To detect HSIL in cervical lesions, Mad2 had a sensitivity of 88.44% and a specificity of 87.23%, Mad2 was less sensitive and more specific than p16INK4a . In SiHa cells, knockdown of Mad2 and BubR1 increased cell growth, reinforced invasion capacity and migration potency, inhibited apoptosis and decreased G2-phase distribution after nocodazole treatment. Oppositely, the overexpression strategies made cells show decreased malignant behaviors, raised apoptosis and increased G2-phase distribution. CONCLUSION Mad2 negativity was specific to identify HSIL immunohistochemistrily. Downregulation of Mad2 and BubR1 increase the malignant behavior and nocodazole resistance of SiHa cells via causing spindle assembly checkpoint defect. This mechanism may contribute to cervical carcinogenesis and resistance to microtubule-targeting drugs.
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Affiliation(s)
- Li Wang
- Department of Obstetrics and Gynecology, Shanghai General Hospital of Nanjing Medical University, Shanghai, China
| | - Jian Wang
- Department of Obstetrics and Gynecology, Sijing Hospital of Songjiang District, Shanghai, Shanghai, China
| | - Yubiao Jin
- Department of Pathology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Zheng
- Department of Pathology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yongbin Yang
- Department of Obstetrics and Gynecology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaowei Xi
- Department of Obstetrics and Gynecology, Shanghai General Hospital of Nanjing Medical University, Shanghai, China
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8
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Abstract
Persistent viral infections require a host cell reservoir that maintains functional copies of the viral genome. To this end, several DNA viruses maintain their genomes as extrachromosomal DNA minichromosomes in actively dividing cells. These viruses typically encode a viral protein that binds specifically to viral DNA genomes and tethers them to host mitotic chromosomes, thus enabling the viral genomes to hitchhike or piggyback into daughter cells. Viruses that use this tethering mechanism include papillomaviruses and the gammaherpesviruses Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus. This review describes the advantages and consequences of persistent extrachromosomal viral genome replication.
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Affiliation(s)
- Tami L Coursey
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Alison A McBride
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA;
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9
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Curtis NL, Bolanos-Garcia VM. The Anaphase Promoting Complex/Cyclosome (APC/C): A Versatile E3 Ubiquitin Ligase. Subcell Biochem 2019; 93:539-623. [PMID: 31939164 DOI: 10.1007/978-3-030-28151-9_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
In the present chapter we discuss the essential roles of the human E3 ubiquitin ligase Anaphase Promoting Complex/Cyclosome (APC/C) in mitosis as well as the emerging evidence of important APC/C roles in cellular processes beyond cell division control such as regulation of genomic integrity and cell differentiation of the nervous system. We consider the potential incipient role of APC/C dysregulation in the pathophysiology of the neurological disorder Alzheimer's disease (AD). We also discuss how certain Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA) viruses take control of the host's cell division regulatory system through harnessing APC/C ubiquitin ligase activity and hypothesise the plausible molecular mechanisms underpinning virus manipulation of the APC/C. We also examine how defects in the function of this multisubunit protein assembly drive abnormal cell proliferation and lastly argue the potential of APC/C as a promising therapeutic target for the development of innovative therapies for the treatment of chronic malignancies such as cancer.
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Affiliation(s)
- Natalie L Curtis
- Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, England, UK
| | - Victor M Bolanos-Garcia
- Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, England, UK.
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10
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Shugoshin 1 is dislocated by KSHV-encoded LANA inducing aneuploidy. PLoS Pathog 2018; 14:e1007253. [PMID: 30212568 PMCID: PMC6136811 DOI: 10.1371/journal.ppat.1007253] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 07/31/2018] [Indexed: 11/30/2022] Open
Abstract
Shugoshin-1 (Sgo1) protects the integrity of the centromeres, and H2A phosphorylation is critical for this process. The mitotic checkpoint kinase Bub1, phosphorylates H2A and ensures fidelity of chromosome segregation and chromosome number. Oncogenic KSHV induces genetic alterations through chromosomal instability (CIN), and its essential antigen LANA regulates Bub1. We show that LANA inhibits Bub1 phosphorylation of H2A and Cdc20, important for chromosome segregation and mitotic signaling. Inhibition of H2A phosphorylation at residue T120 by LANA resulted in dislocation of Sgo1, and cohesin from the centromeres. Arrest of Cdc20 phosphorylation also rescued degradation of Securin and Cyclin B1 at mitotic exit, and interaction of H2A, and Cdc20 with Bub1 was inhibited by LANA. The N-terminal nuclear localization sequence domain of LANA was essential for LANA and Bub1 interaction, reversed LANA inhibited phosphorylation of H2A and Cdc20, and attenuated LANA-induced aneuploidy and cell proliferation. This molecular mechanism whereby KSHV-induced CIN, demonstrated that the NNLS of LANA is a promising target for development of anti-viral therapies targeting KSHV associated cancers. KSHV is a known oncogenic herpes virus associated with human malignancies and lymphoproliferative disorders, which includes Kaposi’s sarcoma, Primary effusion lymphoma, and Multicentric Castleman’s disease. KSHV disrupts the G1 and G2/M checkpoints through multiple pathways. Whether KSHV can directly interfere with spindle checkpoints is not known. Impairment of the mitotic checkpoint protein Bub1 leads to CIN and oncogenesis through displacement of Shugoshin-1. KSHV associated diseases have genetic alterations which are driven by chromosomal instability (CIN), as seen in numerous viral-associated cancer cells. Here we examined the molecular mechanism behind KSHV-induced CIN. We showed that the latent antigen LANA, encoded by KSHV, inhibits Bub1 phosphorylation of H2A and Cdc20, and this led to the dislocation of Shugoshin-1. Our studies demonstrated the direct induction of aneuploidy by LANA. The NNLS domain of LANA serves as an anchor for LANA to promote its multiple functions. We also showed that the NNLS polypeptide can antagonize LANA’s inhibition on Bub1 kinase function, and so rescue the aneuploidy induced by LANA. Development of this property of NNLS is potentially useful for targeted elimination of KSHV-associated cancers.
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11
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Xue Y, Toh SY, He P, Lim T, Lim D, Pang CL, Abastado JP, Thierry F. HPV16-E2 induces prophase arrest and activates the cellular DNA damage response in vitro and in precursor lesions of cervical carcinoma. Oncotarget 2016; 6:34979-91. [PMID: 26474276 PMCID: PMC4741503 DOI: 10.18632/oncotarget.5512] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 10/01/2015] [Indexed: 11/25/2022] Open
Abstract
Cervical intraepithelial neoplasia (CIN) is caused by human papillomavirus (HPV) infection and is the precursor to cervical carcinoma. The completion of the HPV productive life cycle depends on the expression of viral proteins which further determines the severity of the cervical neoplasia. Initiation of the viral productive replication requires expression of the E2 viral protein that cooperates with the E1 viral DNA helicase. A decrease in the viral DNA replication ability and increase in the severity of cervical neoplasia is accompanied by simultaneous elevated expression of E6 and E7 oncoproteins. Here we reveal a novel and important role for the HPV16-E2 protein in controlling host cell cycle during malignant transformation. We showed that cells expressing HPV16-E2 in vitro are arrested in prophase alongside activation of a sustained DDR signal. We uncovered evidence that HPV16-E2 protein is present in vivo in cells that express both mitotic and DDR signals specifically in CIN3 lesions, immediate precursors of cancer, suggesting that E2 may be one of the drivers of genomic instability and carcinogenesis in vivo.
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Affiliation(s)
- Yuezhen Xue
- Institute of Medical Biology, A*STAR, Singapore.,Current address: p53 Laboratory, A*STAR, Singapore
| | | | - Pingping He
- Institute of Medical Biology, A*STAR, Singapore
| | - Thimothy Lim
- Department of Gynaecological Oncology, KK Women's and Children's Hospital, Singapore
| | - Diana Lim
- Department of Pathology, National University Hospital, Singapore
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12
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Chromosomal instability: A common feature and a therapeutic target of cancer. Biochim Biophys Acta Rev Cancer 2016; 1866:64-75. [PMID: 27345585 DOI: 10.1016/j.bbcan.2016.06.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 06/16/2016] [Accepted: 06/17/2016] [Indexed: 01/31/2023]
Abstract
Most cancer cells are aneuploid, containing abnormal numbers of chromosomes, mainly caused by elevated levels of chromosome missegregation, known as chromosomal instability (CIN). These well-recognized, but poorly understood, features of cancers have recently been studied extensively, unraveling causal relationships between CIN and cancer. Here we review recent findings regarding how CIN and aneuploidy occur, how they affect cellular functions, how cells respond to them, and their relevance to diseases, especially cancer. Aneuploid cells are under various kinds of stresses that result in reduced cellular fitness. Nevertheless, genetic heterogeneity derived from CIN allows the selection of cells better adapted to their environment, which supposedly facilitates generation and progression of cancer. We also discuss how we can exploit the properties of cancer cells exhibiting CIN for effective cancer therapy.
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13
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Aydin I, Schelhaas M. Viral Genome Tethering to Host Cell Chromatin: Cause and Consequences. Traffic 2016; 17:327-40. [PMID: 26787361 DOI: 10.1111/tra.12378] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 01/14/2016] [Accepted: 01/14/2016] [Indexed: 12/26/2022]
Abstract
Viruses are small infectious agents that replicate in cells of a host organism and that evolved to use cellular machineries for all stages of the viral life cycle. Here, we critically assess current knowledge on a particular mechanism of persisting viruses, namely, how they tether their genomes to host chromatin, and what consequences arise from this process. A group of persisting DNA viruses, i.e. gamma-herpesviruses and papillomaviruses (PV), uses this tethering strategy to maintain their genomes in the nuclei during cell division. Thus, these viruses face the challenge of viral genome loss during mitosis, as they are transported with the host chromosomes to the nascent daughter nuclei. Incidentally, another group of viruses, certain retroviruses and PV, have adopted this tethering strategy to deliver their genomes into the nuclei of dividing cells during cell entry. By exploiting a phase in the cell cycle when the nuclear envelope is disassembled, viruses bypass the need to engage with the nuclear import machinery. Recent reports suggest that tethering may induce severe cellular consequences that involve activation of mitotic checkpoints, causing missegregation of host chromosomes and genomic instability, which may contribute to cancer.
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Affiliation(s)
- Inci Aydin
- Cell Biology of Virus Infection Unit, Institutes of Molecular Virology and Medical Biochemistry, ZMBE, University of Münster, Münster, Germany.,Cells in Motion, CiM, Cluster of Excellence EXC 1003, Münster, Germany
| | - Mario Schelhaas
- Cell Biology of Virus Infection Unit, Institutes of Molecular Virology and Medical Biochemistry, ZMBE, University of Münster, Münster, Germany.,Cells in Motion, CiM, Cluster of Excellence EXC 1003, Münster, Germany
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Human Papillomavirus Vaccine. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 101:231-322. [DOI: 10.1016/bs.apcsb.2015.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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