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Keuper K, Bartek J, Maya-Mendoza A. The nexus of nuclear envelope dynamics, circular economy and cancer cell pathophysiology. Eur J Cell Biol 2024; 103:151394. [PMID: 38340500 DOI: 10.1016/j.ejcb.2024.151394] [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] [Received: 10/29/2023] [Revised: 02/01/2024] [Accepted: 02/02/2024] [Indexed: 02/12/2024] Open
Abstract
The nuclear envelope (NE) is a critical component in maintaining the function and structure of the eukaryotic nucleus. The NE and lamina are disassembled during each cell cycle to enable an open mitosis. Nuclear architecture construction and deconstruction is a prime example of a circular economy, as it fulfills a highly efficient recycling program bound to continuous assessment of the quality and functionality of the building blocks. Alterations in the nuclear dynamics and lamina structure have emerged as important contributors to both oncogenic transformation and cancer progression. However, the knowledge of the NE breakdown and reassembly is still limited to a fraction of participating proteins and complexes. As cancer cells contain highly diverse nuclei in terms of DNA content, but also in terms of nuclear number, size, and shape, it is of great interest to understand the intricate relationship between these nuclear features in cancer cell pathophysiology. In this review, we provide insights into how those NE dynamics are regulated, and how lamina destabilization processes may alter the NE circular economy. Moreover, we expand the knowledge of the lamina-associated domain region by using strategic algorithms, including Artificial Intelligence, to infer protein associations, assess their function and location, and predict cancer-type specificity with implications for the future of cancer diagnosis, prognosis and treatment. Using this approach we identified NUP98 and MECP2 as potential proteins that exhibit upregulation in Acute Myeloid Leukemia (LAML) patients with implications for early diagnosis.
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Affiliation(s)
- Kristina Keuper
- DNA Replication and Cancer Group, Danish Cancer Institute, Copenhagen, Denmark; Genome Integrity Group, Danish Cancer Institute, Copenhagen, Denmark
| | - Jiri Bartek
- Genome Integrity Group, Danish Cancer Institute, Copenhagen, Denmark; Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SciLifeLab, Stockholm, Sweden
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2
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Uno K, Rastegar B, Jansson C, Durand G, Valind A, Chattopadhyay S, Bertolotti A, Ciceri S, Spreafico F, Collini P, Perotti D, Mengelbier LH, Gisselsson D. A Gradual Transition Toward Anaplasia in Wilms Tumor Through Tolerance to Genetic Damage. Mod Pathol 2024; 37:100382. [PMID: 37951357 DOI: 10.1016/j.modpat.2023.100382] [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] [Received: 06/09/2023] [Revised: 10/23/2023] [Accepted: 11/06/2023] [Indexed: 11/14/2023]
Abstract
Patients with Wilms tumor (WT) in general have excellent survival, but the prognosis of patients belonging to the subgroup of WT with diffuse anaplasia (DA) is poor due to frequent resistance to chemotherapy. We hypothesized that DA WT cells might undergo changes, such as acquiring a persistent tolerance to DNA damage and copy number aberrations (CNAs), which could eventually lead to their resistance to chemotherapy treatment. Tissue sections from chemotherapy-treated DA WTs (n = 12) were compared with chemotherapy-treated nonanaplastic WTs (n = 15) in a tissue microarray system, enabling analysis of 769 tumor regions. All regions were scored for anaplastic features and immunohistochemistry was used to quantify p53 expression, proliferation index (Ki67), and DNA double-strand breaks (γH2AX). CNAs were assessed by array-based genotyping and TP53 mutations using targeted sequencing. Proliferation index and the frequency of DNA double-strand breaks (γH2AX dot expression) increased with higher anaplasia scores. Almost all (95.6%) areas with full-scale anaplasia had TP53 mutations or loss of heterozygosity, along with an increased amount of CNAs. Interestingly, areas with wild-type TP53 with loss of heterozygosity and only one feature of anaplasia (anaplasia score 1) also had significantly higher proliferation indices, more DNA double-strand breaks, and more CNAs than regions without any anaplastic features (score 0); such areas may be preanaplastic cell populations under selective pressure for TP53 mutations. In conclusion, we suggest that chemoresistance of DA WTs may be partly explained by a high proliferative capability of anaplastic cells, which also have a high burden of double-stranded DNA breaks and CNAs, and that there is a gradual emergence of anaplasia in WT.
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Affiliation(s)
- Kaname Uno
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden; Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Bahar Rastegar
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Caroline Jansson
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Geoffroy Durand
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Anders Valind
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden; Now with Childhood Cancer Center, Skåne University Hospital, Lund, Sweden
| | - Subhayan Chattopadhyay
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Alessia Bertolotti
- Diagnostic and Molecular Research Lab, Department of Advanced Diagnostics, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Sara Ciceri
- Molecular Bases of Genetic Risk and Genetic Testing Unit, Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Now with Predictive Medicine: Molecular Bases of Genetic Risk, Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Filippo Spreafico
- Pediatric Oncology Unit, Department of Medical Oncology and Hematology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Paola Collini
- Soft Tissue Tumor Pathology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Daniela Perotti
- Molecular Bases of Genetic Risk and Genetic Testing Unit, Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Now with Predictive Medicine: Molecular Bases of Genetic Risk, Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | | | - David Gisselsson
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden; Division of Oncology-Pathology, Department of Clinical Science, Lund University, Lund, Sweden; Division of Clinical Genetics and Pathology, Department of Laboratory Medicine, Lund University Hospital, Skåne Healthcare Region, Lund, Sweden
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3
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Cimini D. Twenty years of merotelic kinetochore attachments: a historical perspective. Chromosome Res 2023; 31:18. [PMID: 37466740 PMCID: PMC10411636 DOI: 10.1007/s10577-023-09727-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/20/2023] [Accepted: 07/08/2023] [Indexed: 07/20/2023]
Abstract
Micronuclei, small DNA-containing structures separate from the main nucleus, were used for decades as an indicator of genotoxic damage. Micronuclei containing whole chromosomes were considered a biomarker of aneuploidy and were believed to form, upon mitotic exit, from chromosomes that lagged behind in anaphase as all other chromosomes segregated to the poles of the mitotic spindle. However, the mechanism responsible for inducing anaphase lagging chromosomes remained unknown until just over twenty years ago. Here, I summarize what preceded and what followed this discovery, highlighting some of the open questions and opportunities for future investigation.
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Affiliation(s)
- Daniela Cimini
- Department of Biological Sciences and Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, 24061, USA.
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Salidroside inhibits the growth, migration and invasion of Wilms' tumor cells through down-regulation of miR-891b. Life Sci 2019; 222:60-68. [PMID: 30822424 DOI: 10.1016/j.lfs.2019.02.052] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/18/2019] [Accepted: 02/25/2019] [Indexed: 11/20/2022]
Abstract
AIMS Salidroside is a major functional component of Rhodiola rosea L. with a lot of pharmacological effects, including anti-tumor. The present work aimed to explore whether Salidroside could also exhibit anti-tumor functions in Wilms' tumor. MAIN METHODS WIT49 and RM1 cells were treated by various doses of Salidroside. CCK-8 assay, flow cytometry detection, colony formation assay, Transwell assay, RT-qPCR and Western blot analysis were conducted to measure WIT49 and RM1 cells proliferation, apoptosis, migration and invasion. The expression changes of miR-891b in response to Salidroside treatment were tested by RT-qPCR. Rescue assays were performed to test whether miR-891b was a downstream effector of Salidroside. Finally, the involvement of PI3K/AKT/mTOR and NF-κB signaling pathways was studied. KEY FINDINGS Salidroside with concentration of 80 μM significantly reduced WIT49 and RM1 cells viability, survival capacity, migration and invasion, and significantly induced apoptosis. Meanwhile, down-regulation of Cyclin D1, MMP-2 and Vimentin, up-regulations of p53 and p21, as well as cleavage of caspase-3 and -9 were observed in Salidroside-treated cell. miR-891b was down-regulated by Salidroside. And Salidroside did not suppress WIT49 and RM1 cells growth, migration and invasion when miR-891b was overexpressed. Also, the deactivation of PI3K/AKT/mTOR and NF-κB pathways induced by Salidroside was reversed by miR-891b overexpression. SIGNIFICANCE Salidroside inhibits Wilms' tumor cells growth, migration and invasion via down-regulating miR-891b, which leads to the deactivation of PI3K/AKT/mTOR and NF-κB signaling pathways.
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5
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Gisselsson D, Lichtenzstejn D, Kachko P, Karlsson J, Manor E, Mai S. Clonal evolution through genetic bottlenecks and telomere attrition: Potential threats to in vitro data reproducibility. Genes Chromosomes Cancer 2018; 58:452-461. [PMID: 30255964 DOI: 10.1002/gcc.22685] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/20/2018] [Accepted: 09/20/2018] [Indexed: 12/20/2022] Open
Abstract
Tissue cultures of immortalized human cells, also known as established cell lines, are broadly accessible and cost-efficient tools for biomedical research. We here review potential genetic sources of systematic error in cell line experiments due to clonal evolution in vitro. In particular, the authors highlight alterations in telomere function over prolonged culture and population bottlenecks, respectively, as two commonly overlooked phenomena that can result in significant alterations in cell line genotypes over just one or a few passages in vitro. These alterations may include changes in mutation status of oncogenes and large scale chromosomal imbalances. We introduce a simple list of factors to be avoided in order to reduce the risk of data misinterpretation due to clonal evolution, including unacknowledged in vitro selection pressures, prolonged culture per se, harsh population size reductions, experiments at early phases after establishment, and the employment of cell lines not sufficiently analyzed by high resolution genetic techniques.
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Affiliation(s)
- David Gisselsson
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden.,Division of Oncology-Pathology, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Daniel Lichtenzstejn
- Cell Biology, Research Institute of Oncology and Hematology, The Genomic Centre for Cancer Research and Diagnosis, CancerCare Manitoba, University of Manitoba, Winnipeg, Canada
| | - Polina Kachko
- Shraga Segal Department of Microbiology, Immunology and Genetics, Ben Gurion University of the Negev, Beer-Sheva, Israel
| | - Jenny Karlsson
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Esther Manor
- Shraga Segal Department of Microbiology, Immunology and Genetics, Ben Gurion University of the Negev, Beer-Sheva, Israel
| | - Sabine Mai
- Cell Biology, Research Institute of Oncology and Hematology, The Genomic Centre for Cancer Research and Diagnosis, CancerCare Manitoba, University of Manitoba, Winnipeg, Canada
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6
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Chang HB, Zou JZ, He C, Zeng R, Li YY, Ma FF, Liu Z, Ye H, Wu JX. Association between Long Interspersed Nuclear Element-1 Methylation and Relative Telomere Length in Wilms Tumor. Chin Med J (Engl) 2016; 128:3055-61. [PMID: 26608986 PMCID: PMC4795265 DOI: 10.4103/0366-6999.169071] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Background: DNA hypomethylation of long interspersed nuclear elements-1 (LINEs-1) occurs during carcinogenesis, whereas information addressing LINE-1 methylation in Wilms tumor (WT) is limited. The main purpose of our study was to quantify LINE-1 methylation levels and evaluate their relationship with relative telomere length (TL) in WT. Methods: We investigated LINE-1 methylation and relative TL using bisulfite-polymerase chain reaction (PCR) pyrosequencing and quantitative PCR, respectively, in 20 WT tissues, 10 normal kidney tissues and a WT cell line. Significant changes were analyzed by t-tests. Results: LINE-1 methylation levels were significantly lower (P < 0.05) and relative TLs were significantly shorter (P < 0.05) in WT compared with normal kidney. There was a significant positive relationship between LINE-1 methylation and relative TL in WT (r = 0.671, P = 0.001). LINE-1 Methylation levels were significantly associated with global DNA methylation (r = 0.332, P < 0.01). In addition, relative TL was shortened and LINE-1 methylation was decreased in a WT cell line treated with the hypomethylating agent 5-aza-2′-deoxycytidine compared with untreated WT cell line. Conclusion: These results suggest that LINE-1 hypomethylation is common and may be linked to telomere shortening in WT.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jian-Xin Wu
- Department of Biochemistry, Capital Institute of Pediatrics, Beijing 100020, China
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7
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Al-Mayah AHJ, Bright SJ, Bowler DA, Slijepcevic P, Goodwin E, Kadhim MA. Exosome-Mediated Telomere Instability in Human Breast Epithelial Cancer Cells after X Irradiation. Radiat Res 2016; 187:98-106. [PMID: 27959588 DOI: 10.1667/rr14201.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In directly irradiating cells, telomere metabolism is altered and similar effects have been observed in nontargeted cells. Exosomes and their cargo play dominant roles in communicating radiation-induced bystander effects with end points related to DNA damage. Here we report novel evidence that exosomes are also responsible for inducing telomere-related bystander effects. Breast epithelial cancer cells were exposed to either 2 Gy X rays, or exposed to irradiated cell conditioned media (ICCM), or exosomes purified from ICCM. Compared to control cells, telomerase activity decreased in the 2 Gy irradiated cells and both bystander samples after one population doubling. At the first population doubling, telomere length was shorter in the 2 Gy irradiated sample but not in the bystander samples. By 24 population doublings telomerase activity recovered to control levels in all samples; however, the 2 Gy irradiated sample continued to demonstrate short telomeres and both bystander samples acquired shorter telomeres. RNase treatment of exosomes prevented the bystander effects on telomerase and telomere length that were observed at 1 population doubling and 24 population doublings, respectively. Thermal denaturation by boiling eliminated the reduction of telomere length in bystander samples, suggesting that the protein fraction of exosomes also contributes to the telomeric effect. RNase treatment plus boiling abrogated all telomere-related effects in directly irradiated and bystander cell populations. These findings suggest that both proteins and RNAs of exosomes can induce alterations in telomeric metabolism, which can instigate genomic instability in epithelial cancer cells after X-ray irradiation.
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Affiliation(s)
- Ammar H J Al-Mayah
- a Genomic Instability Group, Oxford Brookes University, Gipsy Lane Campus, Headington, Oxford OX3 0BP, United Kingdom
| | - Scott J Bright
- a Genomic Instability Group, Oxford Brookes University, Gipsy Lane Campus, Headington, Oxford OX3 0BP, United Kingdom
| | - Debbie A Bowler
- a Genomic Instability Group, Oxford Brookes University, Gipsy Lane Campus, Headington, Oxford OX3 0BP, United Kingdom
| | - Predrag Slijepcevic
- b Department of Life Sciences, College of Health and Life Sciences, Brunel University, London UB8 3PH, United Kingdom
| | - Edwin Goodwin
- c The New Mexico Consortium, Los Alamos, New Mexico 87544
| | - Munira A Kadhim
- a Genomic Instability Group, Oxford Brookes University, Gipsy Lane Campus, Headington, Oxford OX3 0BP, United Kingdom
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8
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Chromosome Bridges Maintain Kinetochore-Microtubule Attachment throughout Mitosis and Rarely Break during Anaphase. PLoS One 2016; 11:e0147420. [PMID: 26784746 PMCID: PMC4718638 DOI: 10.1371/journal.pone.0147420] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 01/04/2016] [Indexed: 11/19/2022] Open
Abstract
Accurate chromosome segregation during cell division is essential to maintain genome stability, and chromosome segregation errors are causally linked to genetic disorders and cancer. An anaphase chromosome bridge is a particular chromosome segregation error observed in cells that enter mitosis with fused chromosomes/sister chromatids. The widely accepted Breakage/Fusion/Bridge cycle model proposes that anaphase chromosome bridges break during mitosis to generate chromosome ends that will fuse during the following cell cycle, thus forming new bridges that will break, and so on. However, various studies have also shown a link between chromosome bridges and aneuploidy and/or polyploidy. In this study, we investigated the behavior and properties of chromosome bridges during mitosis, with the idea to gain insight into the potential mechanism underlying chromosome bridge-induced aneuploidy. We find that only a small number of chromosome bridges break during anaphase, whereas the rest persist through mitosis into the subsequent cell cycle. We also find that the microtubule bundles (k-fibers) bound to bridge kinetochores are not prone to breakage/detachment, thus supporting the conclusion that k-fiber detachment is not the cause of chromosome bridge-induced aneuploidy. Instead, our data suggest that while the microtubules bound to the kinetochores of normally segregating chromosomes shorten substantially during anaphase, the k-fibers bound to bridge kinetochores shorten only slightly, and may even lengthen, during anaphase. This causes some of the bridge kinetochores/chromosomes to lag behind in a position that is proximal to the cell/spindle equator and may cause the bridged chromosomes to be segregated into the same daughter nucleus or to form a micronucleus.
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9
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Intratumoral genome diversity parallels progression and predicts outcome in pediatric cancer. Nat Commun 2015; 6:6125. [PMID: 25625758 DOI: 10.1038/ncomms7125] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/18/2014] [Indexed: 12/30/2022] Open
Abstract
Genetic differences among neoplastic cells within the same tumour have been proposed to drive cancer progression and treatment failure. Whether data on intratumoral diversity can be used to predict clinical outcome remains unclear. We here address this issue by quantifying genetic intratumoral diversity in a set of chemotherapy-treated childhood tumours. By analysis of multiple tumour samples from seven patients we demonstrate intratumoral diversity in all patients analysed after chemotherapy, typically presenting as multiple clones within a single millimetre-sized tumour sample (microdiversity). We show that microdiversity often acts as the foundation for further genome evolution in metastases. In addition, we find that microdiversity predicts poor cancer-specific survival (60%; P=0.009), independent of other risk factors, in a cohort of 44 patients with chemotherapy-treated childhood kidney cancer. Survival was 100% for patients lacking microdiversity. Thus, intratumoral genetic diversity is common in childhood cancers after chemotherapy and may be an important factor behind treatment failure.
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10
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Kalatova B, Jesenska R, Hlinka D, Dudas M. Tripolar mitosis in human cells and embryos: occurrence, pathophysiology and medical implications. Acta Histochem 2015; 117:111-25. [PMID: 25554607 DOI: 10.1016/j.acthis.2014.11.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 11/26/2014] [Accepted: 11/27/2014] [Indexed: 01/08/2023]
Abstract
Tripolar mitosis is a specific case of cell division driven by typical molecular mechanisms of mitosis, but resulting in three daughter cells instead of the usual count of two. Other variants of multipolar mitosis show even more mitotic poles and are relatively rare. In nature, this phenomenon was frequently observed or suspected in multiple common cancers, infected cells, the placenta, and in early human embryos with impaired pregnancy-yielding potential. Artificial causes include radiation and various toxins. Here we combine several pieces of the most recent evidence for the existence of different types of multipolar mitosis in preimplantation embryos together with a detailed review of the literature. The related molecular and cellular mechanisms are discussed, including the regulation of centriole duplication, mitotic spindle biology, centromere functions, cell cycle checkpoints, mitotic autocorrection mechanisms, and the related complicating factors in healthy and affected cells, including post-mitotic cell-cell fusion often associated with multipolar cell division. Clinical relevance for oncology and embryo selection in assisted reproduction is also briefly discussed in this context.
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11
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Ness KK, Armstrong GT, Kundu M, Wilson CL, Tchkonia T, Kirkland JL. Frailty in childhood cancer survivors. Cancer 2014; 121:1540-7. [PMID: 25529481 DOI: 10.1002/cncr.29211] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/18/2014] [Accepted: 11/18/2014] [Indexed: 12/14/2022]
Abstract
Young adult childhood cancer survivors are at an increased risk of frailty, a physiologic phenotype typically found among older adults. This phenotype is associated with new-onset chronic health conditions and mortality among both older adults and childhood cancer survivors. Mounting evidence suggests that poor fitness, muscular weakness, and cognitive decline are common among adults treated for childhood malignancies, and that risk factors for these outcomes are not limited to those treated with cranial radiation. Although the pathobiology of this phenotype is not known, early cellular senescence, sterile inflammation, and mitochondrial dysfunction in response to initial cancer or treatment-related insults are hypothesized to play a role. To the authors' knowledge, interventions to prevent or remediate frailty among childhood cancer survivors have not been tested to date. Pharmaceutical, nutraceutical, and lifestyle interventions have demonstrated some promise.
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Affiliation(s)
- Kirsten K Ness
- Department of Epidemiology and Cancer Control, St. Jude Children's Research Hospital, Memphis, Tennessee
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12
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Shalaby T, Fiaschetti G, Nagasawa K, Shin-ya K, Baumgartner M, Grotzer M. G-quadruplexes as potential therapeutic targets for embryonal tumors. Molecules 2013; 18:12500-37. [PMID: 24152672 PMCID: PMC6269990 DOI: 10.3390/molecules181012500] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 09/18/2013] [Accepted: 09/25/2013] [Indexed: 12/27/2022] Open
Abstract
Embryonal tumors include a heterogeneous group of highly malignant neoplasms that primarily affect infants and children and are characterized by a high rate of mortality and treatment-related morbidity, hence improved therapies are clearly needed. G-quadruplexes are special secondary structures adopted in guanine (G)-rich DNA sequences that are often present in biologically important regions, e.g. at the end of telomeres and in the regulatory regions of oncogenes such as MYC. Owing to the significant roles that both telomeres and MYC play in cancer cell biology, G-quadruplexes have been viewed as emerging therapeutic targets in oncology and as tools for novel anticancer drug design. Several compounds that target these structures have shown promising anticancer activity in tumor xenograft models and some of them have entered Phase II clinical trials. In this review we examine approaches to DNA targeted cancer therapy, summarize the recent developments of G-quadruplex ligands as anticancer drugs and speculate on the future direction of such structures as a potential novel therapeutic strategy for embryonal tumors of the nervous system.
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Affiliation(s)
- Tarek Shalaby
- Division of Oncology, University Children's Hospital of Zurich, Zurich 8032, Switzerland.
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13
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Short telomeres are frequent in hereditary breast tumors and are associated with high tumor grade. Breast Cancer Res Treat 2013; 141:231-42. [DOI: 10.1007/s10549-013-2696-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 09/02/2013] [Indexed: 01/05/2023]
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14
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Valind A, Jin Y, Gisselsson D. Elevated tolerance to aneuploidy in cancer cells: estimating the fitness effects of chromosome number alterations by in silico modelling of somatic genome evolution. PLoS One 2013; 8:e70445. [PMID: 23894657 PMCID: PMC3722120 DOI: 10.1371/journal.pone.0070445] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 06/18/2013] [Indexed: 12/30/2022] Open
Abstract
An unbalanced chromosome number (aneuploidy) is present in most malignant tumours and has been attributed to mitotic mis-segregation of chromosomes. However, recent studies have shown a relatively high rate of chromosomal mis-segregation also in non-neoplastic human cells, while the frequency of aneuploid cells remains low throughout life in most normal tissues. This implies that newly formed aneuploid cells are subject to negative selection in healthy tissues and that attenuation of this selection could contribute to aneuploidy in cancer. To test this, we modelled cellular growth as discrete time branching processes, during which chromosome gains and losses were generated and their host cells subjected to selection pressures of various magnitudes. We then assessed experimentally the frequency of chromosomal mis-segregation as well as the prevalence of aneuploid cells in human non-neoplastic cells and in cancer cells. Integrating these data into our models allowed estimation of the fitness reduction resulting from a single chromosome copy number change to an average of ≈30% in normal cells. In comparison, cancer cells showed an average fitness reduction of only 6% (p = 0.0008), indicative of aneuploidy tolerance. Simulations based on the combined presence of chromosomal mis-segregation and aneuploidy tolerance reproduced distributions of chromosome aberrations in >400 cancer cases with higher fidelity than models based on chromosomal mis-segregation alone. Reverse engineering of aneuploid cancer cell development in silico predicted that aneuploidy intolerance is a stronger limiting factor for clonal expansion of aneuploid cells than chromosomal mis-segregation rate. In conclusion, our findings indicate that not only an elevated chromosomal mis-segregation rate, but also a generalised tolerance to novel chromosomal imbalances contribute to the genomic landscape of human tumours.
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Affiliation(s)
- Anders Valind
- Department of Clinical Genetics, Lund University and Skåne Regional and University Laboratories, Lund, Sweden
| | - Yuesheng Jin
- Department of Clinical Genetics, Lund University and Skåne Regional and University Laboratories, Lund, Sweden
| | - David Gisselsson
- Department of Clinical Genetics, Lund University and Skåne Regional and University Laboratories, Lund, Sweden
- * E-mail:
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15
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Janssen A, Medema RH. Genetic instability: tipping the balance. Oncogene 2012; 32:4459-70. [PMID: 23246960 DOI: 10.1038/onc.2012.576] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 10/23/2012] [Accepted: 10/24/2012] [Indexed: 02/06/2023]
Abstract
Tumor cells typically contain a genome that is highly divergent from the genome of normal, non-transformed cells. This genetic divergence is caused by a number of distinct changes that the tumor cell acquires during its transformation from a normal cell into a tumorigenic counterpart. Changes to the genome include mutations, deletions, insertions, and also gross chromosomal aberrations, such as chromosome translocations and whole chromosome gains or losses. This genetic disorder of the tumor cell has complicated the identification of crucial driver mutations that cause cancer. Moreover, the large genetic divergence between different tumors causes them to behave very differently, and makes it difficult to predict response to therapy. In addition, tumor cells are genetically unstable and frequently acquire new mutations and/or gross chromosomal aberrations as they divide. This is beneficial for the overall capacity of a tumor to adapt to changes in its environment, but newly acquired genetic alterations can also compromise the genetic dominance of the tumor cell and thus affect tumor cell viability. Here, we review the mechanisms that can cause gross chromosomal aberrations, and discuss how these affect tumor cell viability.
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Affiliation(s)
- A Janssen
- 1] Division of Cell Biology, Netherlands Cancer Institute, Amsterdam, The Netherlands [2] Department of Medical Oncology and Cancer Genomics Center, University Medical Center Utrecht, Utrecht, The Netherlands
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Silkworth WT, Cimini D. Transient defects of mitotic spindle geometry and chromosome segregation errors. Cell Div 2012; 7:19. [PMID: 22883214 PMCID: PMC3509025 DOI: 10.1186/1747-1028-7-19] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 07/24/2012] [Indexed: 12/11/2022] Open
Abstract
Assembly of a bipolar mitotic spindle is essential to ensure accurate chromosome segregation and prevent aneuploidy, and severe mitotic spindle defects are typically associated with cell death. Recent studies have shown that mitotic spindles with initial geometric defects can undergo specific rearrangements so the cell can complete mitosis with a bipolar spindle and undergo bipolar chromosome segregation, thus preventing the risk of cell death associated with abnormal spindle structure. Although this may appear as an advantageous strategy, transient defects in spindle geometry may be even more threatening to a cell population or organism than permanent spindle defects. Indeed, transient spindle geometry defects cause high rates of chromosome mis-segregation and aneuploidy. In this review, we summarize our current knowledge on two specific types of transient spindle geometry defects (transient multipolarity and incomplete spindle pole separation) and describe how these mechanisms cause chromosome mis-segregation and aneuploidy. Finally, we discuss how these transient spindle defects may specifically contribute to the chromosomal instability observed in cancer cells.
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Affiliation(s)
- William T Silkworth
- Department of Biological Sciences, Virginia Tech, 1981 Kraft Dr, Blacksburg, VA, 24061, USA.
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Abstract
Human chromosome 8p23 is a region that has the most frequent heterozygosity in common human adult epithelial malignancies, but its major tumor suppressor gene(s) remain to be identified. Telomerase is activated in most human cancers and is critical for cancer cell growth. However, little is known about the significance of telomerase activation in chromosome instability and cancer initiation. The gene encoding the potent and highly conserved endogenous telomerase inhibitor PinX1 is located at human chromosome 8p23. However, the role of PinX1 in telomerase regulation and cancer development is not clear. Recent works from our group indicate that PinX1 is critical for maintaining telomere length at the optimal length. Furthermore, PinX1 is reduced in a large subset of human breast cancer tissues and cells. Significantly, PinX1 inhibition activates telomerase, and elongates telomeres, eventually leading to chromosome instability, all of which are abrogated by telomerase knockdown or knockout. Moreover, PinX1 allele loss causes majority of mice to develop a variety of epithelial cancers, which display chromosome instability and recapitulate to 8p23 allele loss in humans. These results indicate that PinX1 is a sought-after major tumor suppressor at human chromosome 8p23 that is essential for regulating telomerase activity and maintaining chromosome stability. These results suggest that inhibition of telomerase using PinX1 especially its telomerase inhibitory fragment or other methods might be used to treat cancers that have telomerase activation.
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Affiliation(s)
- Xiao Zhen Zhou
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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Abstract
Aneuploidy is a common feature of cancer cells, and is believed to play a critical role in tumorigenesis and cancer progression. Most cancer cells also exhibit high rates of mitotic chromosome mis-segregation, a phenomenon known as chromosomal instability, which leads to high variability of the karyotype. Here, we describe the nature, nuances, and implications of cancer karyotypic diversity. Moreover, we summarize recent studies aimed at identifying the mitotic defects that may be responsible for inducing chromosome mis-segregation in cancer cells. These include kinetochore attachment errors, spindle assembly checkpoint dysfunction, mitotic spindle defects, and other cell division inaccuracies. Finally, we discuss how such mitotic errors generate karyotypic diversity in cancer cells.
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Ramamoorthy M, Tadokoro T, Rybanska I, Ghosh AK, Wersto R, May A, Kulikowicz T, Sykora P, Croteau DL, Bohr VA. RECQL5 cooperates with Topoisomerase II alpha in DNA decatenation and cell cycle progression. Nucleic Acids Res 2011; 40:1621-35. [PMID: 22013166 PMCID: PMC3287182 DOI: 10.1093/nar/gkr844] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
DNA decatenation mediated by Topoisomerase II is required to separate the interlinked sister chromatids post-replication. SGS1, a yeast homolog of the human RecQ family of helicases interacts with Topoisomerase II and plays a role in chromosome segregation, but this functional interaction has yet to be identified in higher organisms. Here, we report a physical and functional interaction of Topoisomerase IIα with RECQL5, one of five mammalian RecQ helicases, during DNA replication. Direct interaction of RECQL5 with Topoisomerase IIα stimulates the decatenation activity of Topoisomerase IIα. Consistent with these observations, RECQL5 co-localizes with Topoisomerase IIα during S-phase of the cell cycle. Moreover, cells with stable depletions of RECQL5 display a slow proliferation rate, a G2/M cell cycle arrest and late S-phase cycling defects. Metaphase spreads generated from RECQL5-depleted cells exhibit undercondensed and entangled chromosomes. Further, RECQL5-depleted cells activate a G2/M checkpoint and undergo apoptosis. These phenotypes are similar to those observed when Topoisomerase II catalytic activity is inhibited. These results reveal an important role for RECQL5 in the maintenance of genomic stability and a new insight into the decatenation process.
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Affiliation(s)
- Mahesh Ramamoorthy
- Laboratory of Molecular Gerontology, Biomedical Research Center, 251 Bayview Boulevard, National Institute on Aging, NIH, Baltimore, MD 21224, USA
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20
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Zhou XZ, Huang P, Shi R, Lee TH, Lu G, Zhang Z, Bronson R, Lu KP. The telomerase inhibitor PinX1 is a major haploinsufficient tumor suppressor essential for chromosome stability in mice. J Clin Invest 2011; 121:1266-82. [PMID: 21436583 DOI: 10.1172/jci43452] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 01/26/2011] [Indexed: 12/14/2022] Open
Abstract
Telomerase is activated in most human cancers and is critical for cancer cell growth. However, little is known about the significance of telomerase activation in chromosome instability and cancer initiation. The gene encoding the potent endogenous telomerase inhibitor PinX1 (PIN2/TRF1-interacting, telomerase inhibitor 1) is located at human chromosome 8p23, a region frequently exhibiting heterozygosity in many common human cancers, but the function or functions of PinX1 in development and tumorigenesis are unknown. Here we have shown that PinX1 is a haploinsufficient tumor suppressor essential for chromosome stability in mice. We found that PinX1 expression was reduced in most human breast cancer tissues and cell lines. Furthermore, PinX1 heterozygosity and PinX1 knockdown in mouse embryonic fibroblasts activated telomerase and led to concomitant telomerase-dependent chromosomal instability. Moreover, while PinX1-null mice were embryonic lethal, most PinX1+/- mice spontaneously developed malignant tumors with evidence of chromosome instability. Notably, most PinX1 mutant tumors were carcinomas and shared tissues of origin with human cancer types linked to 8p23. PinX1 knockout also shifted the tumor spectrum of p53 mutant mice from lymphoma toward epithelial carcinomas. Thus, PinX1 is a major haploinsufficient tumor suppressor essential for maintaining telomerase activity and chromosome stability. These findings uncover what we believe to be a novel role for PinX1 and telomerase in chromosome instability and cancer initiation and suggest that telomerase inhibition may be potentially used to treat cancers that overexpress telomerase.
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Affiliation(s)
- Xiao Zhen Zhou
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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21
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Generation of trisomies in cancer cells by multipolar mitosis and incomplete cytokinesis. Proc Natl Acad Sci U S A 2010; 107:20489-93. [PMID: 21059955 DOI: 10.1073/pnas.1006829107] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One extra chromosome copy (i.e., trisomy) is the most common type of chromosome aberration in cancer cells. The mechanisms behind the generation of trisomies in tumor cells are largely unknown, although it has been suggested that dysfunction of the spindle assembly checkpoint (SAC) leads to an accumulation of trisomies through failure to correctly segregate sister chromatids in successive cell divisions. By using Wilms tumor as a model for cancers with trisomies, we now show that trisomic cells can form even in the presence of a functional SAC through tripolar cell divisions in which sister chromatid separation proceeds in a regular fashion, but cytokinesis failure nevertheless leads to an asymmetrical segregation of chromosomes into two daughter cells. A model for the generation of trisomies by such asymmetrical cell division accurately predicted several features of clones having extra chromosomes in vivo, including the ratio between trisomies and tetrasomies and the observation that different trisomies found in the same tumor occupy identical proportions of cells and colocalize in tumor tissue. Our findings provide an experimentally validated model explaining how multiple trisomies can occur in tumor cells that still maintain accurate sister chromatid separation at metaphase-anaphase transition and thereby physiologically satisfy the SAC.
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Mengelbier LH, Karlsson J, Lindgren D, Øra I, Isaksson M, Frigyesi I, Frigyesi A, Bras J, Sandstedt B, Gisselsson D. Deletions of 16q in Wilms tumors localize to blastemal-anaplastic cells and are associated with reduced expression of the IRXB renal tubulogenesis gene cluster. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:2609-21. [PMID: 20847289 DOI: 10.2353/ajpath.2010.100130] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Wilms tumor is the most common pediatric renal neoplasm, but few molecular prognostic markers have been identified for this tumor. Somatic deletion in the long arm of chromosome 16 (16q) is known to predict a less favorable outcome in Wilms tumor, but the underlying molecular mechanisms are not known. We show that 16q deletions are typically confined to immature anaplastic-blastic tumor elements, while deletions are absent in maturing tumor components. The smallest region of deletion overlap mapped to a 1.8-Mb segment containing the IRXB gene cluster including IRX3, IRX5, and IRX6, of which IRX3 is a recently identified regulator of tubular maturation during nephrogenesis. Tumors with 16q deletion showed a lower overall mRNA expression of IRXB genes, and 16q-deleted tumor cells failed to express IRX3 while it was expressed in differentiating tubular tumor elements with intact 16q. Consistent with a role for IRX3 in tubular differentiation, gene sets linked to Notch signaling, Rho signaling, and ion channel activity were enriched in tumors with high IRX3 expression, while WTs with low expression were enriched for gene sets linked to cell cycle progression. Low mRNA levels of IRXB genes were associated with diffuse anaplasia, high-stage disease, and death. A disturbed balance between tubular differentiation and self-renewal of anaplastic-blastic elements may thus be one mechanism linking 16q deletion to adverse outcome in Wilms tumor.
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Affiliation(s)
- Linda Holmquist Mengelbier
- Department of Clinical Genetics, University and Regional Laboratories, Lund University, Skåne University Hospital, SE 221 85 Lund, Sweden
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Gisselsson D, Lindgren D, Mengelbier LH, Øra I, Yeger H. Genetic bottlenecks and the hazardous game of population reduction in cell line based research. Exp Cell Res 2010; 316:3379-86. [PMID: 20643124 DOI: 10.1016/j.yexcr.2010.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 06/28/2010] [Accepted: 07/13/2010] [Indexed: 02/06/2023]
Abstract
Established tumour cell lines are ubiquitous tools in research, but their representativity is often debated. One possible caveat is that many cell lines are derived from cells with genomic instability, potentially leading to genotype changes in vitro. We applied SNP-array analysis to an established tumour cell line (WiT49). Even though WiT49 exhibited chromosome segregation errors in 30% of cell divisions, only a single chromosome segment exhibited a shift in copy number after 20 population doublings in culture. In contrast, sub-populations derived from single cells expanded for an equal number of population doublings showed on average 5.8 and 8.9 altered segments compared to the original culture and to each other, respectively. Most copy number variants differentiating these single cell clones corresponded to pre-existing variations in the original culture. Furthermore, no sub-clonal variation was detected in any of the populations derived from single cells. This indicates that genetic bottlenecks resulting from population reduction poses a higher threat to genetic representativity than prolonged culture per se, even in cell lines with a high rate of genomic instability. Genetic bottlenecks should therefore be considered a potential caveat in all studies involving sub-cloning, transfection and other conditions leading to a temporary reduction in cell number.
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Affiliation(s)
- David Gisselsson
- Department of Clinical Genetics, Lund University, University and Regional Laboratories, Lund, Sweden.
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24
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Silkworth WT, Nardi IK, Scholl LM, Cimini D. Multipolar spindle pole coalescence is a major source of kinetochore mis-attachment and chromosome mis-segregation in cancer cells. PLoS One 2009; 4:e6564. [PMID: 19668340 PMCID: PMC2719800 DOI: 10.1371/journal.pone.0006564] [Citation(s) in RCA: 336] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Accepted: 07/03/2009] [Indexed: 11/25/2022] Open
Abstract
Many cancer cells display a CIN (Chromosome Instability) phenotype, by which they exhibit high rates of chromosome loss or gain at each cell cycle. Over the years, a number of different mechanisms, including mitotic spindle multipolarity, cytokinesis failure, and merotelic kinetochore orientation, have been proposed as causes of CIN. However, a comprehensive theory of how CIN is perpetuated is still lacking. We used CIN colorectal cancer cells as a model system to investigate the possible cellular mechanism(s) underlying CIN. We found that CIN cells frequently assembled multipolar spindles in early mitosis. However, multipolar anaphase cells were very rare, and live-cell experiments showed that almost all CIN cells divided in a bipolar fashion. Moreover, fixed-cell analysis showed high frequencies of merotelically attached lagging chromosomes in bipolar anaphase CIN cells, and higher frequencies of merotelic attachments in multipolar vs. bipolar prometaphases. Finally, we found that multipolar CIN prometaphases typically possessed γ-tubulin at all spindle poles, and that a significant fraction of bipolar metaphase/early anaphase CIN cells possessed more than one centrosome at a single spindle pole. Taken together, our data suggest a model by which merotelic kinetochore attachments can easily be established in multipolar prometaphases. Most of these multipolar prometaphase cells would then bi-polarize before anaphase onset, and the residual merotelic attachments would produce chromosome mis-segregation due to anaphase lagging chromosomes. We propose this spindle pole coalescence mechanism as a major contributor to chromosome instability in cancer cells.
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Affiliation(s)
- William T. Silkworth
- Virginia Tech, Department of Biological Sciences, Blacksburg, Virginia, United States of America
| | - Isaac K. Nardi
- Virginia Tech, Department of Biological Sciences, Blacksburg, Virginia, United States of America
| | - Lindsey M. Scholl
- Department of Biology, Oberlin College, Oberlin, Ohio, United States of America
| | - Daniela Cimini
- Virginia Tech, Department of Biological Sciences, Blacksburg, Virginia, United States of America
- * E-mail:
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Radiation and chemotherapy bystander effects induce early genomic instability events: telomere shortening and bridge formation coupled with mitochondrial dysfunction. Mutat Res 2009; 669:131-8. [PMID: 19540247 DOI: 10.1016/j.mrfmmm.2009.06.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Revised: 06/03/2009] [Accepted: 06/09/2009] [Indexed: 11/20/2022]
Abstract
The bridge breakage fusion cycle is a chromosomal instability mechanism responsible for genomic changes. Radiation bystander effects induce genomic instability; however, the mechanism driving this instability is unknown. We examined if radiation and chemotherapy bystander effects induce early genomic instability events such as telomere shortening and bridge formation using a human colon cancer explant model. We assessed telomere lengths, bridge formations, mitochondrial membrane potential and levels of reactive oxygen species in bystander cells exposed to medium from irradiated and chemotherapy-treated explant tissues. Bystander cells exposed to media from 2Gy, 5Gy, FOLFOX treated tumor and matching normal tissue showed a significant reduction in telomere lengths (all p values <0.018) and an increase in bridge formations (all p values <0.017) compared to bystander cells treated with media from unirradiated tissue (0Gy) at 24h. There was no significant difference between 2Gy and 5Gy treatments, or between effects elicited by tumor versus matched normal tissue. Bystander cells exposed to media from 2Gy irradiated tumor tissue showed significant depolarisation of the mitochondrial membrane potential (p=0.012) and an increase in reactive oxygen species levels. We also used bystander cells overexpressing a mitochondrial antioxidant manganese superoxide dismutase (MnSOD) to examine if this antioxidant could rescue the mitochondrial changes and subsequently influence nuclear instability events. In MnSOD cells, ROS levels were reduced (p=0.02) and mitochondrial membrane potential increased (p=0.04). These events were coupled with a decrease in percentage of cells with anaphase bridges and a decrease in the number of cells undergoing telomere length shortening (p values 0.01 and 0.028 respectively). We demonstrate that radiation and chemotherapy bystander responses induce early genomic instability coupled with defects in mitochondrial function. Restoring mitochondrial function through overexpression of MnSOD significantly rescues nuclear instability events; anaphase bridges and telomere length shortening.
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Proctor A, Brownhill SC, Burchill SA. The promise of telomere length, telomerase activity and its regulation in the translocation-dependent cancer ESFT; clinical challenges and utility. Biochim Biophys Acta Mol Basis Dis 2009; 1792:260-74. [PMID: 19264125 DOI: 10.1016/j.bbadis.2009.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 02/19/2009] [Accepted: 02/20/2009] [Indexed: 01/12/2023]
Abstract
The Ewing's sarcoma family of tumours (ESFT) are diagnosed by EWS-ETS gene translocations. The resulting fusion proteins play a role in both the initiation and maintenance of these solid aggressive malignant tumours, suppressing cellular senescence and increasing cell proliferation and survival. EWS-ETS fusion proteins have altered transcriptional activity, inducing expression of a number of different target genes including telomerase. Up-regulation of hTERT is most likely responsible for the high levels of telomerase activity in primary ESFT, although telomerase activity and expression of hTERT are not predictive of outcome. However levels of telomerase activity in peripheral blood may be useful to monitor response to some therapeutics. Despite high levels of telomerase activity, telomeres in ESFT are frequently shorter than those of matched normal cells. Uncertainty about the role that telomerase and regulators of its activity play in the maintenance of telomere length in normal and cancer cells, and lack of studies examining the relationship between telomerase activity, regulators of its activity and their clinical significance in patient samples have limited their introduction into clinical practice. Studies in clinical samples using standardised assays are critical to establish how telomerase and regulators of its activity might best be exploited for patient benefit.
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Affiliation(s)
- Andrew Proctor
- Cancer Research UK Clinical Centre, Leeds Institute of Molecular Medicine, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK
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Qualman S, Lynch J, Bridge J, Parham D, Teot L, Meyer W, Pappo A. Prevalence and clinical impact of anaplasia in childhood rhabdomyosarcoma : a report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group. Cancer 2009; 113:3242-7. [PMID: 18985676 DOI: 10.1002/cncr.23929] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Anapalsia is rare in childhood rhabdomyosarcoma and has not been included in the International Classification of Rhabdomyosarcoma (ICR). A recent review of cases from the Soft Tissue Sarcoma Committee of the Children's Oncology Group (COG) suggests that anaplasia might be more common than previously reported and may impact clinical outcome. METHODS The prevalence of anaplasia (focal or diffuse) was prospectively assessed in 546 eligible cases who were registered in an Intergroup Rhabdomyosarcoma Study Group (IRSG) or COG therapeutic trial from 1995 through 1998. The incidence of anaplasia in tumor samples and its impact in predicting clinical outcome was assessed. RESULTS Overall, 71 (13%) of all samples analyzed had anaplasia. Anaplasia was more common in patients with tumors in favorable sites and was less commonly observed in younger patients and in those with stage II, III, or clinical group III disease. Regardless of its distribution (focal or diffuse), on univariate analysis the presence of anaplasia negatively influenced the failure-free survival rate (63% vs 77% at 5 years) and overall survival (68% vs 82% at 5 years) rates in patients with embryonal rhabdomyosarcoma. This effect was most pronounced in children with intermediate-risk tumors. Anaplasia did not affect outcome in patients with alveolar tumors. CONCLUSIONS The incidence of anaplasia in patients with rhabdomyosarcoma is higher than previously described and may be of prognostic significance in children with intermediate-risk embryonal rhabdomyosarcoma.
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Poonepalli A, Banerjee B, Ramnarayanan K, Palanisamy N, Putti TC, Hande MP. Telomere-mediated genomic instability and the clinico-pathological parameters in breast cancer. Genes Chromosomes Cancer 2008; 47:1098-109. [DOI: 10.1002/gcc.20608] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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29
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Stewénius Y, Jin Y, Ora I, Panagopoulos I, Möller E, Mertens F, Sandstedt B, Alumets J, Akerman M, Merks JH, de Kraker J, Gisselsson D. High-resolution molecular cytogenetic analysis of Wilms tumors highlights diagnostic difficulties among small round cell kidney tumors. Genes Chromosomes Cancer 2008; 47:845-52. [PMID: 18615675 DOI: 10.1002/gcc.20587] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Many solid tumors exhibit characteristic gene fusions, which are reflected by balanced translocations at the cytogenetic level. These changes might be useful diagnostic and prognostic tools. In Wilms tumor (WT, nephroblastoma) no fusions genes or recurrent balanced translocations have been described thus far. To screen for cryptic balanced translocations, we have analyzed 17 renal neoplasms, histopathologically classified as WT, by a combination of G-banding, multicolor FISH, and subtelomeric FISH. This approach revealed several submicroscopic chromosomal aberrations and three different seemingly balanced translocations, resulting in a heterozygous deletion of HACE1, an EWSR1/ERG fusion, and an EWSR1/FLI1 fusion, respectively. As EWSR1 rearrangements are known to be a characteristic of Ewing tumors (ET), our findings illustrate the diagnostic problems regarding small cell kidney tumors and strongly argue for the need of adjuvant diagnostic techniques in this group of neoplasms. In summary, our genomic screening approach proved efficient in finding structural chromosomal aberrations. The fact that no recurrent translocations were found in the WTs of this study argues against the presence of a frequent pathognomonic translocation in this disease entity.
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Affiliation(s)
- Ylva Stewénius
- Department of Clinical Genetics, Lund University Hospital, Lund, Sweden.
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30
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Classification of chromosome segregation errors in cancer. Chromosoma 2008; 117:511-9. [PMID: 18528701 DOI: 10.1007/s00412-008-0169-1] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2008] [Revised: 05/11/2008] [Accepted: 05/13/2008] [Indexed: 01/05/2023]
Abstract
Abnormal chromosome segregation at mitosis is one way by which neoplastic cells accumulate the many genetic abnormalities required for tumour development. In this paper, a straightforward morphology-based classification of chromosome segregation errors in cancer is suggested. This classification distinguishes between abnormalities in spindle symmetry (spindle multipolarity, size-asymmetry of ana-telophase poles) and abnormalities in sister chromatid segregation (chromosome bridges, chromatid bridges, chromosome lagging, acentric fragment lagging). Often, these categories of errors must be combined to accurately describe the events in a single abnormal mitotic cell. The suggested categories can to some extent be distinguished by standard chromatin staining. However, labelling of abnormal mitotic figures by fluorescence in situ hybridization and immunofluorescence enhances the accuracy of classification and also allows visualisation of the segregation of individual chromosomes, making it possible to detect non-disjunction also in the absence of gross alterations in mitotic morphology. Further characterisation of the molecular alterations leading to abnormal chromosome segregation together with the current developments in nano-level and real-time imaging will undoubtedly lead to an improved understanding of chromosome dynamics in cancer cells. Any morphology-based classification of chromosome segregation errors in cancer must therefore be taken as provisional, anticipating a satisfactory integration of morphology and molecular biology.
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31
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Cimini D. Merotelic kinetochore orientation, aneuploidy, and cancer. Biochim Biophys Acta Rev Cancer 2008; 1786:32-40. [PMID: 18549824 DOI: 10.1016/j.bbcan.2008.05.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 04/21/2008] [Accepted: 05/13/2008] [Indexed: 01/16/2023]
Abstract
Accurate chromosome segregation in mitosis is crucial to maintain a diploid chromosome number. A majority of cancer cells are aneuploid and chromosomally unstable, i.e. they tend to gain and lose chromosomes at each mitotic division. Chromosome mis-segregation can arise when cells progress through mitosis with mis-attached kinetochores. Merotelic kinetochore orientation, a type of mis-attachment in which a single kinetochore binds microtubules from two spindle poles rather than just one, can represent a particular threat for dividing cells, as: (i) it occurs frequently in early mitosis; (ii) it is not detected by the spindle assembly checkpoint (unlike other types of mis-attachments); (iii) it can lead to chromosome mis-segregation, and, hence, aneuploidy. A number of studies have recently started to unveil the cellular and molecular mechanisms involved in merotelic kinetochore formation and correction. Here, I review these studies and discuss the relevance of merotelic kinetochore orientation in cancer cell biology.
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Affiliation(s)
- Daniela Cimini
- Virginia Tech, Department of Biological Sciences, 5036 Derring Hall, Blacksburg, VA 24061, USA.
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33
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Gisselsson D, Håkanson U, Stoller P, Marti D, Jin Y, Rosengren AH, Stewénius Y, Kahl F, Panagopoulos I. When the genome plays dice: circumvention of the spindle assembly checkpoint and near-random chromosome segregation in multipolar cancer cell mitoses. PLoS One 2008; 3:e1871. [PMID: 18392149 PMCID: PMC2289843 DOI: 10.1371/journal.pone.0001871] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Accepted: 02/22/2008] [Indexed: 12/21/2022] Open
Abstract
Background Normal cell division is coordinated by a bipolar mitotic spindle, ensuring symmetrical segregation of chromosomes. Cancer cells, however, occasionally divide into three or more directions. Such multipolar mitoses have been proposed to generate genetic diversity and thereby contribute to clonal evolution. However, this notion has been little validated experimentally. Principal Findings Chromosome segregation and DNA content in daughter cells from multipolar mitoses were assessed by multiphoton cross sectioning and fluorescence in situ hybridization in cancer cells and non-neoplastic transformed cells. The DNA distribution resulting from multipolar cell division was found to be highly variable, with frequent nullisomies in the daughter cells. Time-lapse imaging of H2B/GFP-labelled multipolar mitoses revealed that the time from the initiation of metaphase to the beginning of anaphase was prolonged and that the metaphase plates often switched polarity several times before metaphase-anaphase transition. The multipolar metaphase-anaphase transition was accompanied by a normal reduction of cellular cyclin B levels, but typically occurred before completion of the normal separase activity cycle. Centromeric AURKB and MAD2 foci were observed frequently to remain on the centromeres of multipolar ana-telophase chromosomes, indicating that multipolar mitoses were able to circumvent the spindle assembly checkpoint with some sister chromatids remaining unseparated after anaphase. Accordingly, scoring the distribution of individual chromosomes in multipolar daughter nuclei revealed a high frequency of nondisjunction events, resulting in a near-binomial allotment of sister chromatids to the daughter cells. Conclusion The capability of multipolar mitoses to circumvent the spindle assembly checkpoint system typically results in a near-random distribution of chromosomes to daughter cells. Spindle multipolarity could thus be a highly efficient generator of genetically diverse minority clones in transformed cell populations.
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Affiliation(s)
- David Gisselsson
- Department of Clinical Genetics, Lund University Hospital, Lund, Sweden.
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