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Black EM, Ramírez Parrado CA, Trier I, Li W, Joo YK, Pichurin J, Liu Y, Kabeche L. Chk2 sustains PLK1 activity in mitosis to ensure proper chromosome segregation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.08.584115. [PMID: 38559033 PMCID: PMC10979866 DOI: 10.1101/2024.03.08.584115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Polo-like kinase 1 (PLK1) protects against genome instability by ensuring timely and accurate mitotic cell division. PLK1 activity is tightly regulated throughout the cell cycle. Although the pathways that initially activate PLK1 in G2 are well-characterized, the factors that directly regulate PLK1 in mitosis remain poorly understood. Here, we identify that human PLK1 activity is sustained by the DNA damage response kinase Checkpoint kinase 2 (Chk2) in mitosis. Chk2 directly phosphorylates PLK1 T210, a residue on its T-loop whose phosphorylation is essential for full PLK1 kinase activity. Loss of Chk2-dependent PLK1 activity causes increased mitotic errors, including chromosome misalignment, chromosome missegregation, and cytokinetic defects. Moreover, Chk2 deficiency increases sensitivity to PLK1 inhibitors, suggesting that Chk2 status may be an informative biomarker for PLK1 inhibitor efficacy. This work demonstrates that Chk2 sustains mitotic PLK1 activity and protects genome stability through discrete functions in interphase DNA damage repair and mitotic chromosome segregation.
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Estrogens—Origin of Centrosome Defects in Human Cancer? Cells 2022; 11:cells11030432. [PMID: 35159242 PMCID: PMC8833882 DOI: 10.3390/cells11030432] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 12/22/2022] Open
Abstract
Estrogens are associated with a variety of diseases and play important roles in tumor development and progression. Centrosome defects are hallmarks of human cancers and contribute to ongoing chromosome missegragation and aneuploidy that manifest in genomic instability and tumor progression. Although several mechanisms underlie the etiology of centrosome aberrations in human cancer, upstream regulators are hardly known. Accumulating experimental and clinical evidence points to an important role of estrogens in deregulating centrosome homeostasis and promoting karyotype instability. Here, we will summarize existing literature of how natural and synthetic estrogens might contribute to structural and numerical centrosome defects, genomic instability and human carcinogenesis.
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Russi M, Marson D, Fermeglia A, Aulic S, Fermeglia M, Laurini E, Pricl S. The fellowship of the RING: BRCA1, its partner BARD1 and their liaison in DNA repair and cancer. Pharmacol Ther 2021; 232:108009. [PMID: 34619284 DOI: 10.1016/j.pharmthera.2021.108009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 08/22/2021] [Accepted: 09/20/2021] [Indexed: 12/12/2022]
Abstract
The breast cancer type 1 susceptibility protein (BRCA1) and its partner - the BRCA1-associated RING domain protein 1 (BARD1) - are key players in a plethora of fundamental biological functions including, among others, DNA repair, replication fork protection, cell cycle progression, telomere maintenance, chromatin remodeling, apoptosis and tumor suppression. However, mutations in their encoding genes transform them into dangerous threats, and substantially increase the risk of developing cancer and other malignancies during the lifetime of the affected individuals. Understanding how BRCA1 and BARD1 perform their biological activities therefore not only provides a powerful mean to prevent such fatal occurrences but can also pave the way to the development of new targeted therapeutics. Thus, through this review work we aim at presenting the major efforts focused on the functional characterization and structural insights of BRCA1 and BARD1, per se and in combination with all their principal mediators and regulators, and on the multifaceted roles these proteins play in the maintenance of human genome integrity.
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Affiliation(s)
- Maria Russi
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Domenico Marson
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Alice Fermeglia
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Suzana Aulic
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Maurizio Fermeglia
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Erik Laurini
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Sabrina Pricl
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy; Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland.
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Hu W, Li M, Zhang Q, Liu C, Wang X, Li J, Qiu S, Li L. Establishment of a novel CNV-related prognostic signature predicting prognosis in patients with breast cancer. J Ovarian Res 2021; 14:103. [PMID: 34364397 PMCID: PMC8349487 DOI: 10.1186/s13048-021-00823-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/10/2021] [Indexed: 01/17/2023] Open
Abstract
Background Copy number variation (CNVs) is a key factor in breast cancer development. This study determined prognostic molecular characteristics to predict breast cancer through performing a comprehensive analysis of copy number and gene expression data. Methods Breast cancer expression profiles, CNV and complete information from The Cancer Genome Atlas (TCGA) dataset were collected. Gene Expression Omnibus (GEO) chip data sets (GSE20685 and GSE31448) containing breast cancer samples were used as external validation sets. Univariate survival COX analysis, multivariate survival COX analysis, least absolute shrinkage and selection operator (LASSO), Chi square, Kaplan-Meier (KM) survival curve and receiver operating characteristic (ROC) analysis were applied to build a gene signature model and assess its performance. Results A total of 649 CNV related-differentially expressed gene obtained from TCGA-breast cancer dataset were related to several cancer pathways and functions. A prognostic gene sets with 9 genes were developed to stratify patients into high-risk and low-risk groups, and its prognostic performance was verified in two independent patient cohorts (n = 327, 246). The result uncovered that 9-gene signature could independently predict breast cancer prognosis. Lower mutation of PIK3CA and higher mutation of TP53 and CDH1 were found in samples with high-risk score compared with samples with low-risk score. Patients in the high-risk group showed higher immune score, malignant clinical features than those in the low-risk group. The 9-gene signature developed in this study achieved a higher AUC. Conclusion The current research established a 5-CNV gene signature to evaluate prognosis of breast cancer patients, which may innovate clinical application of prognostic assessment. Supplementary Information The online version contains supplementary material available at 10.1186/s13048-021-00823-y.
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Affiliation(s)
- Wei Hu
- Department of Thyroid and Breast Surgery, Zibo Central Hospital, Zibo, 255036, China
| | - Mingyue Li
- Department of Rehabilitation Medicine, The Third Affilated Hospital, Sun Yat-sen University, Guangzhou, 510000, China
| | - Qi Zhang
- Blood Transfusion Department, Zibo Central Hospital, Zibo, 255036, China
| | - Chuan Liu
- Department of Thyroid and Breast Surgery, Zibo Central Hospital, Zibo, 255036, China
| | - Xinmei Wang
- Department of Pathology, ZiBo Central Hospital, Zibo, 255036, China
| | - Jing Li
- Department of Pathology, ZiBo Central Hospital, Zibo, 255036, China.
| | - Shusheng Qiu
- Department of Thyroid and Breast Surgery, Zibo Central Hospital, Zibo, 255036, China.
| | - Liang Li
- Department of Thyroid and Breast Surgery, Zibo Central Hospital, Zibo, 255036, China.
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The p53/p73 - p21 CIP1 tumor suppressor axis guards against chromosomal instability by restraining CDK1 in human cancer cells. Oncogene 2021; 40:436-451. [PMID: 33168930 PMCID: PMC7808936 DOI: 10.1038/s41388-020-01524-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/02/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022]
Abstract
Whole chromosome instability (W-CIN) is a hallmark of human cancer and contributes to the evolvement of aneuploidy. W-CIN can be induced by abnormally increased microtubule plus end assembly rates during mitosis leading to the generation of lagging chromosomes during anaphase as a major form of mitotic errors in human cancer cells. Here, we show that loss of the tumor suppressor genes TP53 and TP73 can trigger increased mitotic microtubule assembly rates, lagging chromosomes, and W-CIN. CDKN1A, encoding for the CDK inhibitor p21CIP1, represents a critical target gene of p53/p73. Loss of p21CIP1 unleashes CDK1 activity which causes W-CIN in otherwise chromosomally stable cancer cells. Consequently, induction of CDK1 is sufficient to induce abnormal microtubule assembly rates and W-CIN. Vice versa, partial inhibition of CDK1 activity in chromosomally unstable cancer cells corrects abnormal microtubule behavior and suppresses W-CIN. Thus, our study shows that the p53/p73 - p21CIP1 tumor suppressor axis, whose loss is associated with W-CIN in human cancer, safeguards against chromosome missegregation and aneuploidy by preventing abnormally increased CDK1 activity.
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Guo P, Tian Z, Kong X, Yang L, Shan X, Dong B, Ding X, Jing X, Jiang C, Jiang N, Yu Y. FadA promotes DNA damage and progression of Fusobacterium nucleatum-induced colorectal cancer through up-regulation of chk2. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2020; 39:202. [PMID: 32993749 PMCID: PMC7523382 DOI: 10.1186/s13046-020-01677-w] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 08/17/2020] [Indexed: 12/14/2022]
Abstract
Background Globally, colorectal cancer (CRC) affects more than 1 million people each year. In addition to non-modifiable and other environmental risk factors, Fusobacterium nucleatum infection has been linked to CRC recently. In this study, we explored mechanisms underlying the role of Fusobacterium nucleatum infection in the progression of CRC in a mouse model. Methods C57BL/6 J-Adenomatous polyposis coli (APC) Min/J mice [APC (Min/+)] were treated with Fusobacterium nucleatum (109 cfu/mL, 0.2 mL/time/day, i.g., 12 weeks), saline, or FadA knockout (FadA−/−) Fusobacterium nucleatum. The number, size, and weight of CRC tumors were determined in isolated tumor masses. The human CRC cell lines HCT29 and HT116 were treated with lentiviral vectors overexpressing chk2 or silencing β-catenin. DNA damage was determined by Comet assay and γH2AX immunofluorescence assay and flow cytometry. The mRNA expression of chk2 was determined by RT-qPCR. Protein expression of FadA, E-cadherin, β-catenin, and chk2 were determined by Western blot analysis. Results Fusobacterium nucleatum treatment promoted DNA damage in CRC in APC (Min/+) mice. Fusobacterium nucleatum also increased the number of CRC cells that were in the S phase of the cell cycle. FadA−/− reduced tumor number, size, and burden in vivo. FadA−/− also reduced DNA damage, cell proliferation, expression of E-cadherin and chk2, and cells in the S phase. Chk2 overexpression elevated DNA damage and tumor growth in APC (Min/+) mice. Conclusions In conclusion, this study provided evidence that Fusobacterium nucleatum induced DNA damage and cell growth in CRC through FadA-dependent activation of the E-cadherin/β-catenin pathway, leading to up-regulation of chk2.
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Affiliation(s)
- Pin Guo
- Department of Neurosurgery, The Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
| | - Zibin Tian
- Department of Gastroenterology, The Affiliated Hospital of Qingdao University, No. 16, Jiangsu Road, Qingdao, 266003, Shandong Province, People's Republic of China
| | - Xinjuan Kong
- Department of Gastroenterology, The Affiliated Hospital of Qingdao University, No. 16, Jiangsu Road, Qingdao, 266003, Shandong Province, People's Republic of China
| | - Lin Yang
- Department of Gastroenterology, The Affiliated Hospital of Qingdao University, No. 16, Jiangsu Road, Qingdao, 266003, Shandong Province, People's Republic of China
| | - Xinzhi Shan
- Department of Gastroenterology, The Affiliated Hospital of Qingdao University, No. 16, Jiangsu Road, Qingdao, 266003, Shandong Province, People's Republic of China
| | - Bingzi Dong
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Qingdao, 266003, People's Republic of China
| | - Xueli Ding
- Department of Gastroenterology, The Affiliated Hospital of Qingdao University, No. 16, Jiangsu Road, Qingdao, 266003, Shandong Province, People's Republic of China
| | - Xue Jing
- Department of Gastroenterology, The Affiliated Hospital of Qingdao University, No. 16, Jiangsu Road, Qingdao, 266003, Shandong Province, People's Republic of China
| | - Chen Jiang
- Department of Gastroenterology, The Affiliated Hospital of Qingdao University, No. 16, Jiangsu Road, Qingdao, 266003, Shandong Province, People's Republic of China
| | - Na Jiang
- Department of Gastroenterology, The Affiliated Hospital of Qingdao University, No. 16, Jiangsu Road, Qingdao, 266003, Shandong Province, People's Republic of China
| | - Yanan Yu
- Department of Gastroenterology, The Affiliated Hospital of Qingdao University, No. 16, Jiangsu Road, Qingdao, 266003, Shandong Province, People's Republic of China.
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Wagenbach M, Vicente JJ, Ovechkina Y, Domnitz S, Wordeman L. Functional characterization of MCAK/Kif2C cancer mutations using high-throughput microscopic analysis. Mol Biol Cell 2020; 31:580-588. [PMID: 31746663 PMCID: PMC7202071 DOI: 10.1091/mbc.e19-09-0503] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The microtubule (MT)-depolymerizing activity of MCAK/Kif2C can be quantified by expressing the motor in cultured cells and measuring tubulin fluorescence levels after enough hours have passed to allow tubulin autoregulation to proceed. This method allows us to score the impact of point mutations within the motor domain. We found that, despite their distinctly different activities, many mutations that impact transport kinesins also impair MCAK/Kif2C's depolymerizing activity. We improved our workflow using CellProfiler to significantly speed up the imaging and analysis of transfected cells. This allowed us to rapidly interrogate a number of MCAK/Kif2C motor domain mutations documented in the cancer database cBioPortal. We found that a large proportion of these mutations adversely impact the motor. Using green fluorescent protein-FKBP-MCAK CRISPR cells we found that one deleterious hot-spot mutation increased chromosome instability in a wild-type (WT) background, suggesting that such mutants have the potential to promote tumor karyotype evolution. We also found that increasing WT MCAK/Kif2C protein levels over that of endogenous MCAK/Kif2C similarly increased chromosome instability. Thus, endogenous MCAK/Kif2C activity in normal cells is tuned to a mean level to achieve maximal suppression of chromosome instability.
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Affiliation(s)
- Mike Wagenbach
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195
| | - Juan Jesus Vicente
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195
| | - Yulia Ovechkina
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195
| | - Sarah Domnitz
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195
| | - Linda Wordeman
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195
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Nai S, Shi Y, Ru H, Ding Y, Geng Q, Li Z, Dong MQ, Xu X, Li J. Chk2-dependent phosphorylation of myosin phosphatase targeting subunit 1 (MYPT1) regulates centrosome maturation. Cell Cycle 2019; 18:2651-2659. [PMID: 31416392 PMCID: PMC6773232 DOI: 10.1080/15384101.2019.1654795] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/17/2019] [Accepted: 08/07/2019] [Indexed: 12/16/2022] Open
Abstract
Checkpoint kinase 2 (Chk2) is a pivotal effector kinase in the DNA damage response, with an emerging role in mitotic chromosome segregation. In this study, we show that Chk2 interacts with myosin phosphatase targeting subunit 1 (MYPT1), the targeting subunit of protein phosphatase 1cβ (PP1cβ). Previous studies have shown that MYPT1 is phosphorylated by CDK1 at S473 during mitosis, and subsequently docks to the polo-binding domain of PLK1 and dephosphorylates PLK1. Herein we present data that Chk2 phosphorylates MYPT1 at S507 in vitro and in vivo, which antagonizes pS473. Chk2 inhibition results in failure of γ-tubulin recruitment to the centrosomes, phenocopying Plk1 inhibition defects. These aberrancies were also observed in the MYPT1-S507A stable transfectants, suggesting that Chk2 exerts its effect on centrosomes via MYPT1. Collectively, we have identified a Chk2-MYPT1-PLK1 axis in regulating centrosome maturation. Abbreviations: Chk2: checkpoint kinase 2; MYPT1: myosin phosphatase targeting subunit 1; PP1cβ: protein phosphatase 1c β; Noc: nocodazole; IP: immunoprecipitation; IB: immunoblotting; LC-MS/MS: liquid chromatography-tandem mass spectrometry; Chk2: checkpoint kinase 2; KD: kinase domain; WT: wild type; Ub: ubiquitin; DAPI: 4',6-diamidino-2-phenylindole; IF: Immunofluorescence; IR: ionizing radiation; siCHK2: siRNA targeting CHK2.
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Affiliation(s)
- Shanshan Nai
- Beijing Key Laboratory of DNA damage Response, College of Life Sciences, Capital Normal University, Beijing, China
| | - Yingxin Shi
- Beijing Key Laboratory of DNA damage Response, College of Life Sciences, Capital Normal University, Beijing, China
| | - Huanwei Ru
- Beijing Key Laboratory of DNA damage Response, College of Life Sciences, Capital Normal University, Beijing, China
| | - Yuehe Ding
- National Institute of Biological Sciences, Beijing, China
| | - Qizhi Geng
- Beijing Key Laboratory of DNA damage Response, College of Life Sciences, Capital Normal University, Beijing, China
| | - Zhe Li
- Beijing Key Laboratory of DNA damage Response, College of Life Sciences, Capital Normal University, Beijing, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing, China
| | - Xingzhi Xu
- Beijing Key Laboratory of DNA damage Response, College of Life Sciences, Capital Normal University, Beijing, China
- Guangdong Key Laboratory of Genome Stability & Disease Prevention, Shenzhen University School of Medicine, Shenzhen, China
| | - Jing Li
- Beijing Key Laboratory of DNA damage Response, College of Life Sciences, Capital Normal University, Beijing, China
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9
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Böhly N, Kistner M, Bastians H. Mild replication stress causes aneuploidy by deregulating microtubule dynamics in mitosis. Cell Cycle 2019; 18:2770-2783. [PMID: 31448675 DOI: 10.1080/15384101.2019.1658477] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Chromosomal instability (CIN) causes structural and numerical chromosome aberrations and represents a hallmark of cancer. Replication stress (RS) has emerged as a driver for structural chromosome aberrations while mitotic defects can cause whole chromosome missegregation and aneuploidy. Recently, first evidence indicated that RS can also influence chromosome segregation in cancer cells exhibiting CIN, but the underlying mechanisms remain unknown. Here, we show that chromosomally unstable cancer cells suffer from very mild RS, which allows efficient proliferation and which can be mimicked by treatment with very low concentrations of aphidicolin. Both, endogenous RS and aphidicolin-induced very mild RS cause chromosome missegregation during mitosis leading to the induction of aneuploidy. Moreover, RS triggers an increase in microtubule plus end growth rates in mitosis, an abnormality previously identified to cause chromosome missegregation in cancer cells. In fact, RS-induced chromosome missegregation is mediated by increased mitotic microtubule growth rates and is suppressed after restoration of proper microtubule growth rates and upon rescue of replication stress. Hence, very mild and cancer-relevant RS triggers aneuploidy by deregulating microtubule dynamics in mitosis.
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Affiliation(s)
- Nicolas Böhly
- Institute of Molecular Oncology, Section for Cellular Oncology, Georg-August University Göttingen, Göttingen Center for Molecular Biosciences (GZMB) and University Medical Center Göttingen (UMG) , Göttingen , Germany
| | - Magdalena Kistner
- Institute of Molecular Oncology, Section for Cellular Oncology, Georg-August University Göttingen, Göttingen Center for Molecular Biosciences (GZMB) and University Medical Center Göttingen (UMG) , Göttingen , Germany
| | - Holger Bastians
- Institute of Molecular Oncology, Section for Cellular Oncology, Georg-August University Göttingen, Göttingen Center for Molecular Biosciences (GZMB) and University Medical Center Göttingen (UMG) , Göttingen , Germany
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Janiszewska H, Bąk A, Skonieczka K, Jaśkowiec A, Kiełbiński M, Jachalska A, Czyżewska M, Jaźwiec B, Kuliszkiewicz-Janus M, Czyż J, Kuliczkowski K, Haus O. Constitutional mutations of the CHEK2 gene are a risk factor for MDS, but not for de novo AML. Leuk Res 2018; 70:74-78. [PMID: 29902706 DOI: 10.1016/j.leukres.2018.05.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 05/20/2018] [Accepted: 05/31/2018] [Indexed: 12/25/2022]
Abstract
CHEK2 plays a key role in cellular response to DNA damage, and also in regulation of mitosis and maintenance of chromosomal stability. In patients newly diagnosed with myelodysplastic syndrome (MDS, n = 107) or acute myeloid leukemia (AML, n = 117) congenital CHEK2 mutations (c.444 + 1G > A, c.1100delC, del5395, p.I157 T) were tested by PCR and sequencing analysis. The karyotype of bone marrow cells of each patient was assessed at disease diagnosis using classical cytogenetic methods and fluorescence in situ hybridization. The CHEK2 mutations were strongly associated with the risk of MDS (p < 0.0001) but not with the risk of de novo AML (p = 0.798). In CHEK2-positive MDS patients, two times higher frequency of aberrant karyotypes than in CHEK2-negative patients was found (71% vs. 37%, p = 0.015). In CHEK2-positive patients with cytogenetic abnormalities, subtypes of MDS: refractory anemia with excess blasts-1 or 2, associated with unfavorable disease prognosis, were diagnosed two times more often than in CHEK2-negative cases with aberrations (78% vs. 44%). In conclusion, the congenital CHEK2 inactivation is strongly associated with the risk of MDS and with a poorer prognosis of the disease. However, the chromosomal instability in AML is not correlated with the hereditary dysfunction of CHEK2.
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Affiliation(s)
- Hanna Janiszewska
- Department of Clinical Genetics, Faculty of Medicine, Collegium Medicum, Bydgoszcz, Nicolaus Copernicus University, Toruń, Poland.
| | - Aneta Bąk
- Department of Clinical Genetics, Faculty of Medicine, Collegium Medicum, Bydgoszcz, Nicolaus Copernicus University, Toruń, Poland
| | - Katarzyna Skonieczka
- Department of Clinical Genetics, Faculty of Medicine, Collegium Medicum, Bydgoszcz, Nicolaus Copernicus University, Toruń, Poland
| | - Anna Jaśkowiec
- Department of Hematology, Blood Neoplasms and Bone Marrow Transplantation, Medical University, Wrocław, Poland
| | - Marek Kiełbiński
- Department of Hematology, Blood Neoplasms and Bone Marrow Transplantation, Medical University, Wrocław, Poland
| | - Anna Jachalska
- Department of Hematology, Faculty of Medicine, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Poland
| | | | - Bożena Jaźwiec
- Department of Hematology, Blood Neoplasms and Bone Marrow Transplantation, Medical University, Wrocław, Poland
| | | | - Jarosław Czyż
- Department of Hematology, Faculty of Medicine, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Poland
| | - Kazimierz Kuliczkowski
- Department of Hematology, Blood Neoplasms and Bone Marrow Transplantation, Medical University, Wrocław, Poland
| | - Olga Haus
- Department of Clinical Genetics, Faculty of Medicine, Collegium Medicum, Bydgoszcz, Nicolaus Copernicus University, Toruń, Poland; Department of Hematology, Blood Neoplasms and Bone Marrow Transplantation, Medical University, Wrocław, Poland
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Cirillo L, Gotta M, Meraldi P. The Elephant in the Room: The Role of Microtubules in Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1002:93-124. [DOI: 10.1007/978-3-319-57127-0_5] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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12
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Li Z, Shao C, Kong Y, Carlock C, Ahmad N, Liu X. DNA Damage Response-Independent Role for MDC1 in Maintaining Genomic Stability. Mol Cell Biol 2017; 37:e00595-16. [PMID: 28193847 PMCID: PMC5394279 DOI: 10.1128/mcb.00595-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 12/08/2016] [Accepted: 02/06/2017] [Indexed: 02/04/2023] Open
Abstract
MDC1 is a central player in checkpoint activation and subsequent DNA repair following DNA damage. Although MDC1 has been studied extensively, many of its known functions, to date, pertain to the DNA damage response (DDR) pathway. Herein we report a novel function of phosphorylated MDC1 that is independent of ATM and DNA damage and is required for proper mitotic progression and maintenance of genomic stability. We demonstrate that MDC1 is an in vivo target of Plk1 and that phosphorylated MDC1 is dynamically localized to nuclear envelopes, centrosomes, kinetochores, and midbodies. Knockdown of MDC1 or abrogation of Plk1 phosphorylation of MDC1 causes a delay of the prometaphase-metaphase transition. It is significant that mice with reduced levels of MDC1 showed an elevated level of spontaneous tumors in aged animals. Our results demonstrate that MDC1 also plays a fundamentally significant role in maintenance of genomic stability through a DDR-independent pathway.
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Affiliation(s)
- Zhiguo Li
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Chen Shao
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Yifan Kong
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Colin Carlock
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Nihal Ahmad
- Department of Dermatology, University of Wisconsin, Madison, Wisconsin, USA
| | - Xiaoqi Liu
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
- Center for Cancer Research, Purdue University, West Lafayette, Indiana, USA
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13
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Sajesh BV, McManus KJ. Targeting SOD1 induces synthetic lethal killing in BLM- and CHEK2-deficient colorectal cancer cells. Oncotarget 2016; 6:27907-22. [PMID: 26318585 PMCID: PMC4695034 DOI: 10.18632/oncotarget.4875] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 07/21/2015] [Indexed: 12/22/2022] Open
Abstract
Cancer is a major cause of death throughout the world, and there is a large need for better and more personalized approaches to combat the disease. Over the past decade, synthetic lethal approaches have been developed that are designed to exploit the aberrant molecular origins (i.e. defective genes) that underlie tumorigenesis. BLM and CHEK2 are two evolutionarily conserved genes that are somatically altered in a number of tumor types. Both proteins normally function in preserving genome stability through facilitating the accurate repair of DNA double strand breaks. Thus, uncovering synthetic lethal interactors of BLM and CHEK2 will identify novel candidate drug targets and lead chemical compounds. Here we identify an evolutionarily conserved synthetic lethal interaction between SOD1 and both BLM and CHEK2 in two distinct cell models. Using quantitative imaging microscopy, real-time cellular analyses, colony formation and tumor spheroid models we show that SOD1 silencing and inhibition (ATTM and LCS-1 treatments), or the induction of reactive oxygen species (2ME2 treatment) induces selective killing within BLM- and CHEK2-deficient cells relative to controls. We further show that increases in reactive oxygen species follow SOD1 silencing and inhibition that are associated with the persistence of DNA double strand breaks, and increases in apoptosis. Collectively, these data identify SOD1 as a novel candidate drug target in BLM and CHEK2 cancer contexts, and further suggest that 2ME2, ATTM and LCS-1 are lead therapeutic compounds warranting further pre-clinical study.
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Affiliation(s)
- Babu V Sajesh
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada.,Research Institute of Oncology and Hematology, Winnipeg, Manitoba, Canada
| | - Kirk J McManus
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada.,Research Institute of Oncology and Hematology, Winnipeg, Manitoba, Canada
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14
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CHK2-BRCA1 tumor-suppressor axis restrains oncogenic Aurora-A kinase to ensure proper mitotic microtubule assembly. Proc Natl Acad Sci U S A 2016; 113:1817-22. [PMID: 26831064 DOI: 10.1073/pnas.1525129113] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BRCA1 (breast cancer type 1 susceptibility protein) is a multifunctional tumor suppressor involved in DNA damage response, DNA repair, chromatin regulation, and mitotic chromosome segregation. Although the nuclear functions of BRCA1 have been investigated in detail, its role during mitosis is little understood. It is clear, however, that loss of BRCA1 in human cancer cells leads to chromosomal instability (CIN), which is defined as a perpetual gain or loss of whole chromosomes during mitosis. Moreover, our recent work has revealed that the mitotic function of BRCA1 depends on its phosphorylation by the tumor-suppressor kinase Chk2 (checkpoint kinase 2) and that this regulation is required to ensure normal microtubule plus end assembly rates within mitotic spindles. Intriguingly, loss of the positive regulation of BRCA1 leads to increased oncogenic Aurora-A activity, which acts as a mediator for abnormal mitotic microtubule assembly resulting in chromosome missegregation and CIN. However, how the CHK2-BRCA1 tumor suppressor axis restrains oncogenic Aurora-A during mitosis to ensure karyotype stability remained an open question. Here we uncover a dual molecular mechanism by which the CHK2-BRCA1 axis restrains oncogenic Aurora-A activity during mitosis and identify BRCA1 itself as a target for Aurora-A relevant for CIN. In fact, Chk2-mediated phosphorylation of BRCA1 is required to recruit the PP6C-SAPS3 phosphatase, which acts as a T-loop phosphatase inhibiting Aurora-A bound to BRCA1. Consequently, loss of CHK2 or PP6C-SAPS3 promotes Aurora-A activity associated with BRCA1 in mitosis. Aurora-A, in turn, then phosphorylates BRCA1 itself, thereby inhibiting the mitotic function of BRCA1 and promoting mitotic microtubule assembly, chromosome missegregation, and CIN.
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15
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Zannini L, Delia D, Buscemi G. CHK2 kinase in the DNA damage response and beyond. J Mol Cell Biol 2014; 6:442-57. [PMID: 25404613 PMCID: PMC4296918 DOI: 10.1093/jmcb/mju045] [Citation(s) in RCA: 287] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 09/17/2014] [Accepted: 09/24/2014] [Indexed: 12/21/2022] Open
Abstract
The serine/threonine kinase CHK2 is a key component of the DNA damage response. In human cells, following genotoxic stress, CHK2 is activated and phosphorylates >20 proteins to induce the appropriate cellular response, which, depending on the extent of damage, the cell type, and other factors, could be cell cycle checkpoint activation, induction of apoptosis or senescence, DNA repair, or tolerance of the damage. Recently, CHK2 has also been found to have cellular functions independent of the presence of nuclear DNA lesions. In particular, CHK2 participates in several molecular processes involved in DNA structure modification and cell cycle progression. In this review, we discuss the activity of CHK2 in response to DNA damage and in the maintenance of the biological functions in unstressed cells. These activities are also considered in relation to a possible role of CHK2 in tumorigenesis and, as a consequence, as a target of cancer therapy.
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Affiliation(s)
- Laura Zannini
- Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Amadeo 42, 20133 Milan, Italy
| | - Domenico Delia
- Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Amadeo 42, 20133 Milan, Italy
| | - Giacomo Buscemi
- Department of Biosciences, University of Milan, via Celoria 26, 20133 Milan, Italy
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16
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Kononenko AV, Bansal R, Lee NCO, Grimes BR, Masumoto H, Earnshaw WC, Larionov V, Kouprina N. A portable BRCA1-HAC (human artificial chromosome) module for analysis of BRCA1 tumor suppressor function. Nucleic Acids Res 2014; 42:gku870. [PMID: 25260588 PMCID: PMC4245969 DOI: 10.1093/nar/gku870] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BRCA1 is involved in many disparate cellular functions, including DNA damage repair, cell-cycle checkpoint activation, gene transcriptional regulation, DNA replication, centrosome function and others. The majority of evidence strongly favors the maintenance of genomic integrity as a principal tumor suppressor activity of BRCA1. At the same time some functional aspects of BRCA1 are not fully understood. Here, a HAC (human artificial chromosome) module with a regulated centromere was constructed for delivery and expression of the 90 kb genomic copy of the BRCA1 gene into BRCA1-deficient human cells. A battery of functional tests was carried out to demonstrate functionality of the exogenous BRCA1. In separate experiments, we investigated the role of BRCA1 in maintenance of heterochromatin integrity within a human functional kinetochore. We demonstrated that BRCA1 deficiency results in a specific activation of transcription of higher-order alpha-satellite repeats (HORs) assembled into heterochromatin domains flanking the kinetochore. At the same time no detectable elevation of transcription was observed within HORs assembled into centrochromatin domains. Thus, we demonstrated a link between BRCA1 deficiency and kinetochore dysfunction and extended previous observations that BRCA1 is required to silence transcription in heterochromatin in specific genomic loci. This supports the hypothesis that epigenetic alterations of the kinetochore initiated in the absence of BRCA1 may contribute to cellular transformation.
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Affiliation(s)
- Artem V Kononenko
- Developmental Therapeutics Branch, National Cancer Institute, Bethesda, MD 20892, USA
| | - Ruchi Bansal
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
| | - Nicholas C O Lee
- Developmental Therapeutics Branch, National Cancer Institute, Bethesda, MD 20892, USA
| | - Brenda R Grimes
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
| | - Hiroshi Masumoto
- Laboratory of Cell Engineering, Department of Frontier Research, Kazusa DNA, Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland
| | - Vladimir Larionov
- Developmental Therapeutics Branch, National Cancer Institute, Bethesda, MD 20892, USA
| | - Natalay Kouprina
- Developmental Therapeutics Branch, National Cancer Institute, Bethesda, MD 20892, USA
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17
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Douglas P, Ye R, Trinkle-Mulcahy L, Neal J, De Wever V, Morrice N, Meek K, Lees-Miller S. Polo-like kinase 1 (PLK1) and protein phosphatase 6 (PP6) regulate DNA-dependent protein kinase catalytic subunit (DNA-PKcs) phosphorylation in mitosis. Biosci Rep 2014; 34:e00113. [PMID: 24844881 PMCID: PMC4069685 DOI: 10.1042/bsr20140051] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 04/25/2014] [Accepted: 05/20/2014] [Indexed: 01/28/2023] Open
Abstract
The protein kinase activity of the DNA-PKcs (DNA-dependent protein kinase catalytic subunit) and its autophosphorylation are critical for DBS (DNA double-strand break) repair via NHEJ (non-homologous end-joining). Recent studies have shown that depletion or inactivation of DNA-PKcs kinase activity also results in mitotic defects. DNA-PKcs is autophosphorylated on Ser2056, Thr2647 and Thr2609 in mitosis and phosphorylated DNA-PKcs localize to centrosomes, mitotic spindles and the midbody. DNA-PKcs also interacts with PP6 (protein phosphatase 6), and PP6 has been shown to dephosphorylate Aurora A kinase in mitosis. Here we report that DNA-PKcs is phosphorylated on Ser3205 and Thr3950 in mitosis. Phosphorylation of Thr3950 is DNA-PK-dependent, whereas phosphorylation of Ser3205 requires PLK1 (polo-like kinase 1). Moreover, PLK1 phosphorylates DNA-PKcs on Ser3205 in vitro and interacts with DNA-PKcs in mitosis. In addition, PP6 dephosphorylates DNA-PKcs at Ser3205 in mitosis and after IR (ionizing radiation). DNA-PKcs also phosphorylates Chk2 on Thr68 in mitosis and both phosphorylation of Chk2 and autophosphorylation of DNA-PKcs in mitosis occur in the apparent absence of Ku and DNA damage. Our findings provide mechanistic insight into the roles of DNA-PKcs and PP6 in mitosis and suggest that DNA-PKcs' role in mitosis may be mechanistically distinct from its well-established role in NHEJ.
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Key Words
- dna-dependent protein kinase
- midbody
- mitosis
- polo-like protein kinase 1
- protein phosphatase 6
- atm, ataxia telangiectasia mutated
- chk2, checkpoint kinase 2
- dmem, dulbecco’s modified eagle’s medium
- dna-pkcs, dna-dependent protein kinase catalytic subunit
- dapi, 4′,6-diamidino-2-phenylindole
- dsb, dna double-strand break
- fha, forkhead associated
- gfp, green fluorescent protein
- ir, ionizing radiation
- mem, minimum essential medium alpha
- nhej, non-homologous end-joining
- pipes, 1,4-piperazinediethanesulfonic acid
- plk1, polo-like kinase-1
- pp6, protein phosphatase 6
- sirna, small interfering rna
- tpx2, targeting protein for xklp2
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Affiliation(s)
- Pauline Douglas
- *Departments of Biochemistry & Molecular Biology and Oncology, Southern Alberta Cancer Research Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, Canada, T2N 4N1
| | - Ruiqiong Ye
- *Departments of Biochemistry & Molecular Biology and Oncology, Southern Alberta Cancer Research Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, Canada, T2N 4N1
| | - Laura Trinkle-Mulcahy
- †Department of Cellular & Molecular Medicine and Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario, Canada, K1H 8M5
| | - Jessica A. Neal
- ‡Departments of Pathobiology & Diagnostic Investigation, and Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, U.S.A
| | - Veerle De Wever
- §Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 4N1
| | - Nick A. Morrice
- ∥Beatson Institute for Cancer Research, Glasgow G61 1BD Scotland, U.K
| | - Katheryn Meek
- ‡Departments of Pathobiology & Diagnostic Investigation, and Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, U.S.A
| | - Susan P. Lees-Miller
- *Departments of Biochemistry & Molecular Biology and Oncology, Southern Alberta Cancer Research Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, Canada, T2N 4N1
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18
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Palazzo L, Della Monica R, Visconti R, Costanzo V, Grieco D. ATM controls proper mitotic spindle structure. Cell Cycle 2014; 13:1091-100. [PMID: 24553124 PMCID: PMC4013160 DOI: 10.4161/cc.27945] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/20/2014] [Accepted: 01/21/2014] [Indexed: 11/19/2022] Open
Abstract
The recessive ataxia-telangiectasia (A-T) syndrome is characterized by cerebellar degeneration, immunodeficiency, cancer susceptibility, premature aging, and insulin-resistant diabetes and is caused by loss of function of the ATM kinase, a member of the phosphoinositide 3-kinase-like protein kinases (PIKKs) family. ATM plays a crucial role in the DNA damage response (DDR); however, the complexity of A-T features suggests that ATM may regulate other cellular functions. Here we show that ATM affects proper bipolar mitotic spindle structure independently of DNA damage. In addition, we find that in mitosis ATM forms a complex with the poly(ADP)ribose (PAR) polymerase Tankyrase (TNKS) 1, the spindle pole protein NuMA1, and breast cancer susceptibility protein BRCA1, another crucial DDR player. Our evidence indicates that the complex is required for efficient poly(ADP)ribosylation of NuMA1. We find further that a mutant NuMA1 version, non-phosphorylatable at potential ATM-dependent phosphorylation sites, is poorly PARylated and induces loss of spindle bipolarity. Our findings may help to explain crucial A-T features and provide further mechanistic rationale for TNKS inhibition in cancer therapy.
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Affiliation(s)
- Luca Palazzo
- DMMBM; University of Naples “Federico II”; Naples, Italy
- Ceinge Biotecnologie Avanzate; Naples, Italy
| | - Rosa Della Monica
- DMMBM; University of Naples “Federico II”; Naples, Italy
- Ceinge Biotecnologie Avanzate; Naples, Italy
| | | | | | - Domenico Grieco
- DMMBM; University of Naples “Federico II”; Naples, Italy
- Ceinge Biotecnologie Avanzate; Naples, Italy
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19
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Shang Z, Yu L, Lin YF, Matsunaga S, Shen CY, Chen BPC. DNA-PKcs activates the Chk2-Brca1 pathway during mitosis to ensure chromosomal stability. Oncogenesis 2014; 3:e85. [PMID: 24492479 PMCID: PMC3940919 DOI: 10.1038/oncsis.2013.49] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 12/11/2013] [Accepted: 12/16/2013] [Indexed: 01/06/2023] Open
Abstract
The catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is known to have a critical role in DNA double-strand break repair. We have previously reported that DNA-PKcs is activated when cells enter mitosis and functions in mitotic spindle assembly and chromosome segregation. Here we report that DNA-PKcs is the upstream regulator of the Chk2-Brca1 pathway, which impacts microtubule dynamics, kinetochore attachment and chromosomal segregation in mitosis. Downstream from Chk2, Brca1 promotes monoubiquitination of γ-tubulin to inhibit microtubule nucleation and growth. We found that DNA-PKcs is essential for mitotic Chk2 phosphorylation at Thr68. As in Chk2- and Brca1-deficient cells, loss of DNA-PKcs resulted in chromosome misalignment and lagging during anaphase owing to elevation in microtubule dynamics. Importantly, these mitotic aberrations in DNA-PKcs-defective cells were alleviated by the overexpression of phosphomimetic Chk2 or Brca1 mutant proteins but not their wild-type counterparts. Taken together, these results demonstrate that DNA-PKcs regulates mitotic spindle organization and chromosomal instability via the Chk2-Brca1 signaling pathway.
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Affiliation(s)
- Z Shang
- Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - L Yu
- Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Y-F Lin
- Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - S Matsunaga
- Division of Molecular Pharmacology, Department of Pathophysiological and Therapeutic Science, Tottori University, Yonago, Japan
| | - C-Y Shen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, ROC
| | - B P C Chen
- Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
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20
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Abstract
Chemotherapy occupies an important position in the treatment of gastric cancer. Platinum drugs are commonly chemotherapy drugs for gastric cancer; however, sensitivity to these drugs varies among different patients. The breast cancer susceptibility gene 1 (BRCA1) is a tumor suppressor gene that is associated with sensitivity to platinum drugs. At present, the research on the BRCA1 gene is mainly focused on breast cancer, and there have been fewer studies on gastric cancer. This paper will give an overview of the structure and function of the BRCA1 gene and the relationship between BRCA1 and gastric cancer.
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21
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Orr B, Compton DA. A double-edged sword: how oncogenes and tumor suppressor genes can contribute to chromosomal instability. Front Oncol 2013; 3:164. [PMID: 23825799 PMCID: PMC3695391 DOI: 10.3389/fonc.2013.00164] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/06/2013] [Indexed: 12/21/2022] Open
Abstract
Most solid tumors are characterized by abnormal chromosome numbers (aneuploidy) and karyotypic profiling has shown that the majority of these tumors are heterogeneous and chromosomally unstable. Chromosomal instability (CIN) is defined as persistent mis-segregation of whole chromosomes and is caused by defects during mitosis. Large-scale genome sequencing has failed to reveal frequent mutations of genes encoding proteins involved in mitosis. On the contrary, sequencing has revealed that most mutated genes in cancer fall into a limited number of core oncogenic signaling pathways that regulate the cell cycle, cell growth, and apoptosis. This led to the notion that the induction of oncogenic signaling is a separate event from the loss of mitotic fidelity, but a growing body of evidence suggests that oncogenic signaling can deregulate cell cycle progression, growth, and differentiation as well as cause CIN. These new results indicate that the induction of CIN can no longer be considered separately from the cancer-associated driver mutations. Here we review the primary causes of CIN in mitosis and discuss how the oncogenic activation of key signal transduction pathways contributes to the induction of CIN.
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Affiliation(s)
- Bernardo Orr
- Department of Biochemistry, Geisel School of Medicine at Dartmouth , Hanover, NH , USA ; The Norris-Cotton Cancer Center, Geisel School of Medicine at Dartmouth , Hanover, NH , USA
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22
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Abstract
Mutations of the breast and ovarian cancer susceptibility gene 1 (BRCA1) account for about 40-45% of hereditary breast cancer cases. Moreover, a significant fraction of sporadic (non-hereditary) breast and ovarian cancers exhibit reduced or absent expression of the BRCA1 protein, suggesting an additional role for BRCA1 in sporadic cancers. BRCA1 follows the classic pattern of a highly penetrant Knudsen-type tumor suppressor gene in which one allele is inactivated through a germ-line mutation and the other is mutated or deleted within the tumor. BRCA1 is a multi-functional protein but it is not fully understood which function(s) is (are) most important for tumor suppression, nor is it clear why BRCA1-mutations confer a high risk for breast and ovarian cancers and not a broad spectrum of tumor types. Here, we will review BRCA1 functions in the DNA damage response (DDR), which are likely to contribute to tumor suppression. In the process, we will highlight some of the controversies and unresolved issues in the field. We will also describe a recently identified and under-investigated role for BRCA1 in the regulation of telomeres and the implications of this role in the DDR and cancer suppression.
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Affiliation(s)
- Eliot M Rosen
- Department of Oncology, Georgetown University School of Medicine Washington, DC, USA ; Department of Biochemistry, Molecular and Cellular Biology, Georgetown University School of Medicine Washington, DC, USA ; Department of Radiation Medicine, Georgetown University School of Medicine Washington, DC, USA
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