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Qian J, Peng M, Li Y, Liu W, Zou X, Chen H, Zhou S, Xiao S, Zhou J. Case report: A germline CHEK1 c.613 + 2T>C leads to a splicing error in a family with multiple cancer patients. Front Oncol 2024; 14:1380093. [PMID: 38686193 PMCID: PMC11056527 DOI: 10.3389/fonc.2024.1380093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 03/21/2024] [Indexed: 05/02/2024] Open
Abstract
Background Genome instability plays a crucial role in promoting tumor development. Germline mutations in genes responsible for DNA repair are often associated with familial cancer syndromes. A noticeable exception is the CHEK1 gene. Despite its well-established role in homologous recombination, germline mutations in CHEK1 are rarely reported. Case presentation In this report, we present a patient diagnosed with ovarian clear cell carcinoma who has a family history of cancer. Her relatives include a grandfather with esophageal cancer, a father with gastric cancer, and an uncle with a brain tumor. The patient carried a typical genomic profile of clear cell carcinoma including mutations in KRAS, PPP2R1A, and PIK3R1. Importantly, her paired peripheral blood cells harbored a germline CHEK1 mutation, CHEK1 exon 6 c.613 + 2T>C, which was also found in her father. Unfortunately, the CHEK1 status of her grandfather and uncle remains unknown due to the unavailability of their specimens. Further evaluation via RT-PCR confirmed a splicing error in the CHEK1 gene, resulting in truncation at the kinase domain region, indicative of a loss-of-function mutation. Conclusion This case highlights a rare germline CHEK1 mutation within a family with a history of cancer. The confirmed splicing error at the mRNA level underscores the functional consequences of this mutation. Documenting such cases is vital for future evaluation of inheritance patterns, clinical penetrance of the mutation, and its association with specific cancer types.
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Affiliation(s)
- Jun Qian
- Department of Gynecology and Obstetrics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Min Peng
- Department of Gynecology and Obstetrics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yanan Li
- Molecular Genetics Laboratory, Suzhou Sano Precision Medicine Ltd., Suzhou, China
| | - Wei Liu
- Department of Gynecology and Obstetrics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xinwei Zou
- Department of Gynecology and Obstetrics, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Huafei Chen
- Molecular Genetics Laboratory, Suzhou Sano Precision Medicine Ltd., Suzhou, China
| | - Sujuan Zhou
- Molecular Genetics Laboratory, Suzhou Sano Precision Medicine Ltd., Suzhou, China
| | - Sheng Xiao
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Jinhua Zhou
- Department of Gynecology and Obstetrics, The First Affiliated Hospital of Soochow University, Suzhou, China
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Knoblochova L, Duricek T, Vaskovicova M, Zorzompokou C, Rayova D, Ferencova I, Baran V, Schultz RM, Hoffmann ER, Drutovic D. CHK1-CDC25A-CDK1 regulate cell cycle progression and protect genome integrity in early mouse embryos. EMBO Rep 2023; 24:e56530. [PMID: 37694680 PMCID: PMC10561370 DOI: 10.15252/embr.202256530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 09/12/2023] Open
Abstract
After fertilization, remodeling of the oocyte and sperm genomes is essential to convert these highly differentiated and transcriptionally quiescent cells into early cleavage-stage blastomeres that are transcriptionally active and totipotent. This developmental transition is accompanied by cell cycle adaptation, such as lengthening or shortening of the gap phases G1 and G2. However, regulation of these cell cycle changes is poorly understood, especially in mammals. Checkpoint kinase 1 (CHK1) is a protein kinase that regulates cell cycle progression in somatic cells. Here, we show that CHK1 regulates cell cycle progression in early mouse embryos by restraining CDK1 kinase activity due to CDC25A phosphatase degradation. CHK1 kinase also ensures the long G2 phase needed for genome activation and reprogramming gene expression in two-cell stage mouse embryos. Finally, Chk1 depletion leads to DNA damage and chromosome segregation errors that result in aneuploidy and infertility.
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Affiliation(s)
- Lucie Knoblochova
- Institute of Animal Physiology and Genetics of the Czech Academy of SciencesLibechovCzech Republic
- Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Tomas Duricek
- Institute of Animal Physiology and Genetics of the Czech Academy of SciencesLibechovCzech Republic
| | - Michaela Vaskovicova
- Institute of Animal Physiology and Genetics of the Czech Academy of SciencesLibechovCzech Republic
| | - Chrysoula Zorzompokou
- Institute of Animal Physiology and Genetics of the Czech Academy of SciencesLibechovCzech Republic
| | - Diana Rayova
- Institute of Animal Physiology and Genetics of the Czech Academy of SciencesLibechovCzech Republic
| | - Ivana Ferencova
- Institute of Animal Physiology and Genetics of the Czech Academy of SciencesLibechovCzech Republic
| | - Vladimir Baran
- Institute of Animal Physiology, Centre of Biosciences, Slovak Academy of SciencesKosiceSlovakia
| | - Richard M Schultz
- Department of BiologyUniversity of PennsylvaniaPhiladelphiaPAUSA
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary MedicineUniversity of CaliforniaDavisCAUSA
| | - Eva R Hoffmann
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular Medicine, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - David Drutovic
- Institute of Animal Physiology and Genetics of the Czech Academy of SciencesLibechovCzech Republic
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3
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Baran V, Mayer A. Checkpoint Kinase 1 Is a Key Signal Transducer of DNA Damage in the Early Mammalian Cleavage Embryo. Int J Mol Sci 2023; 24:ijms24076778. [PMID: 37047751 PMCID: PMC10095474 DOI: 10.3390/ijms24076778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 03/01/2023] [Accepted: 04/04/2023] [Indexed: 04/14/2023] Open
Abstract
After fertilization, remodeling of the oocyte and sperm genome is essential for the successful initiation of mitotic activity in the fertilized oocyte and subsequent proliferative activity of the early embryo. Despite the fact that the molecular mechanisms of cell cycle control in early mammalian embryos are in principle comparable to those in somatic cells, there are differences resulting from the specific nature of the gene totipotency of the blastomeres of early cleavage embryos. In this review, we focus on the Chk1 kinase as a key transduction factor in monitoring the integrity of DNA molecules during early embryogenesis.
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Affiliation(s)
- Vladimír Baran
- Institute of Animal Physiology, Centre of Biosciences, Slovak Academy of Sciences, Šoltésovej 4, 040 00 Košice, Slovakia
| | - Alexandra Mayer
- Department of Obstetrics and Gynecology, First Faculty of Medicine, Charles University, 12000 Prague, Czech Republic
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4
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Shen D, Liu H, Qian F, Wang P. Design, synthesis and evaluation of novel thienopyridazine derivatives as Chk1/2 inhibitors. Bioorg Chem 2022; 121:105704. [PMID: 35240418 DOI: 10.1016/j.bioorg.2022.105704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 02/17/2022] [Accepted: 02/22/2022] [Indexed: 11/02/2022]
Abstract
In order to search for novel checkpoint kinase 1/2 (Chk1) inhibitors, we have designed and synthesized a series of new compounds incorporating thienopyridazine core. Bioevaluation showed that compounds 10j, 10i, 13e and 10o exhibited relatively good inhibitory activity. Notably, compound 10o displayed high selectivity against a panel of kinases and inhibited Chk1/2 signaling pathway stimulated by DNA damage drugs in cellular level. Molecular docking of 10o to the ATP-binding site of Chk1 kinase domain indicated the existence of polar interactions between 10o and the ATP-ribose-binding residues of Chk1. In mouse HT-29 xenografts, a synergistic effect was observed. Co-treatment by CPT-11 and 10o significantly diminished the tumor volume, indicating the great potential of 10o as a candidate of Chk1/2 inhibitor.
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Affiliation(s)
- Dadong Shen
- Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, China; Research & Development Center, Zhejiang Medicine Co. Ltd, Shaoxing 312500, China
| | - Hanyu Liu
- Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, China
| | - Feng Qian
- Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, China
| | - Pu Wang
- Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, China.
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5
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Disrupted mitochondrial homeostasis coupled with mitotic arrest generates antineoplastic oxidative stress. Oncogene 2022; 41:427-443. [PMID: 34773075 PMCID: PMC8755538 DOI: 10.1038/s41388-021-02105-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/24/2021] [Accepted: 10/27/2021] [Indexed: 12/13/2022]
Abstract
Reactive oxygen species (ROS) serve as critical signals in various cellular processes. Excessive ROS cause cell death or senescence and mediates the therapeutic effect of many cancer drugs. Recent studies showed that ROS increasingly accumulate during G2/M arrest, the underlying mechanism, however, has not been fully elucidated. Here, we show that in cancer cells treated with anticancer agent TH287 or paclitaxel that causes M arrest, mitochondria accumulate robustly and produce excessive mitochondrial superoxide, which causes oxidative DNA damage and undermines cell survival and proliferation. While mitochondrial mass is greatly increased in cells arrested at M phase, the mitochondrial function is compromised, as reflected by reduced mitochondrial membrane potential, increased SUMOylation and acetylation of mitochondrial proteins, as well as an increased metabolic reliance on glycolysis. CHK1 functional disruption decelerates cell cycle, spares the M arrest and attenuates mitochondrial oxidative stress. Induction of mitophagy and blockade of mitochondrial biogenesis, measures that reduce mitochondrial accumulation, also decelerate cell cycle and abrogate M arrest-coupled mitochondrial oxidative stress. These results suggest that cell cycle progression and mitochondrial homeostasis are interdependent and coordinated, and that impairment of mitochondrial homeostasis and the associated redox signaling may mediate the antineoplastic effect of the M arrest-inducing chemotherapeutics. Our findings provide insights into the fate of cells arrested at M phase and have implications in cancer therapy.
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6
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Abstract
Cells confront DNA damage in every cell cycle. Among the most deleterious types of DNA damage are DNA double-strand breaks (DSBs), which can cause cell lethality if unrepaired or cancers if improperly repaired. In response to DNA DSBs, cells activate a complex DNA damage checkpoint (DDC) response that arrests the cell cycle, reprograms gene expression, and mobilizes DNA repair factors to prevent the inheritance of unrepaired and broken chromosomes. Here we examine the DDC, induced by DNA DSBs, in the budding yeast model system and in mammals.
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Affiliation(s)
- David P Waterman
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA;
| | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA;
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA;
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7
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PIBF1 suppresses the ATR/CHK1 signaling pathway and promotes proliferation and motility of triple-negative breast cancer cells. Breast Cancer Res Treat 2020; 182:591-600. [PMID: 32529408 DOI: 10.1007/s10549-020-05732-0] [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: 05/06/2020] [Accepted: 06/05/2020] [Indexed: 02/06/2023]
Abstract
PURPOSE This study evaluates the oncogenic role of PIBF1 in triple-negative breast cancer (TNBC). TNBC is considered to have a poorer prognosis than other types of breast cancer and is associated with high risk of recurrence and distant metastasis. Currently, there are no effective therapies for the TNBC patients with distant metastasis due to the lack of targeted therapeutic options. METHODS The effects of PIBF1 knockdown on the cell viability and motility of TNBC cell lines were investigated. Effects of PIBF1 overexpression on tumorigenicity and cell motility were confirmed using Ba/F3 cell line and xenograft study on BALB/c nude mice. RESULTS In TNBC cell lines that highly express PIBF1, knockdown of PIBF1 induces apoptosis and suppresses cell viability and motility with activation of the ATR/CHK1 signaling pathway. Moreover, the oncogenic function of PIBF1 was confirmed using the Ba/F3 cell line. CONCLUSION For the first time, these findings clarify the role of PIBF1 in regulating ATR/CHK1 signaling pathway and inhibiting the proliferation and migration of TNBC cell lines. These results demonstrate the oncogenic roles of PIBF1 and provide new insights into the function and the molecular mechanism of PIBF1 in malignant TNBC.
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8
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Homma H, Nojima H, Kaida A, Miura M. Induction of endomitosis-like event in HeLa cells following CHK1 inhibitor treatment. Biochem Biophys Res Commun 2019; 520:492-497. [DOI: 10.1016/j.bbrc.2019.09.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 09/12/2019] [Indexed: 11/15/2022]
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9
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Ebili HO, Iyawe VO, Adeleke KR, Salami BA, Banjo AA, Nolan C, Rakha E, Ellis I, Green A, Agboola AOJ. Checkpoint Kinase 1 Expression Predicts Poor Prognosis in Nigerian Breast Cancer Patients. Mol Diagn Ther 2018; 22:79-90. [PMID: 29075961 DOI: 10.1007/s40291-017-0302-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Checkpoint kinase 1 (CHEK1), a DNA damage sensor and cell death pathway stimulator, is regarded as an oncogene in tumours, where its activities are considered essential for tumourigenesis and the survival of cancer cells treated with chemotherapy and radiotherapy. In breast cancer, CHEK1 expression has been associated with an aggressive tumour phenotype, the triple-negative breast cancer subtype, an aberrant response to tamoxifen, and poor prognosis. However, the relevance of CHEK1 expression has, hitherto, not been investigated in an indigenous African population. We therefore aimed to investigate the clinicopathological, biological, and prognostic significance of CHEK1 expression in a cohort of Nigerian breast cancer cases. MATERIAL AND METHODS Tissue microarrays of 207 Nigerian breast cancer cases were tested for CHEK1 expression using immunohistochemistry. The clinicopathological, molecular, and prognostic characteristics of CHEK1-positive tumours were determined using the Chi-squared test and Kaplan-Meier and Cox regression analyses in SPSS Version 16. RESULTS Nuclear expression of CHEK1 was present in 61% of breast tumours and was associated with tumour size, triple-negative cancer, basal-like phenotype, the epithelial-mesenchymal transition, p53 over-expression, DNA homologous repair pathway dysfunction, and poor prognosis. CONCLUSIONS The rate expression of CHEK1 is high in Nigerian breast cancer cases and is associated with an aggressive phenotype and poor prognosis.
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Affiliation(s)
- Henry Okuchukwu Ebili
- Department of Morbid Anatomy and Histopathology, Olabisi Onabanjo University, Sagamu Campus, Hospital Road, Sagamu, Ogun State, Nigeria.
| | - Victoria O Iyawe
- Department of Morbid Anatomy and Histopathology, Olabisi Onabanjo University, Sagamu Campus, Hospital Road, Sagamu, Ogun State, Nigeria
| | - Kikelomo Rachel Adeleke
- Department of Morbid Anatomy and Histopathology, Olabisi Onabanjo University, Sagamu Campus, Hospital Road, Sagamu, Ogun State, Nigeria
| | | | - Adekunbiola Aina Banjo
- Department of Morbid Anatomy and Histopathology, Olabisi Onabanjo University, Sagamu Campus, Hospital Road, Sagamu, Ogun State, Nigeria
| | - Chris Nolan
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Emad Rakha
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Ian Ellis
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Andrew Green
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham, UK
| | - Ayodeji Olayinka Johnson Agboola
- Department of Morbid Anatomy and Histopathology, Olabisi Onabanjo University, Sagamu Campus, Hospital Road, Sagamu, Ogun State, Nigeria
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10
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Abstract
The chemical treatment of cancer started with the realization that DNA damaging agents such as mustard gas present notable antitumoural properties. Consequently, early drug development focused on genotoxic chemicals, some of which are still widely used in the clinic. However, the efficacy of such therapies is often limited by the side effects of these drugs on healthy cells. A refinement to this approach is to use compounds that can exploit the presence of DNA damage in cancer cells. Given that replication stress (RS) is a major source of genomic instability in cancer, targeting the RS-response kinase ataxia telangiectasia and Rad3-related protein (ATR) has emerged as a promising alternative. With ATR inhibitors now entering clinical trials, we here revisit the biology behind this strategy and discuss potential biomarkers that could be used for a better selection of patients who respond to therapy.
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Affiliation(s)
- Emilio Lecona
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Oscar Fernandez-Capetillo
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
- Science for Life Laboratory, Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden.
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11
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Liu S, Yao X, Zhang D, Sheng J, Wen X, Wang Q, Chen G, Li Z, Du Z, Zhang X. Analysis of Transcription Factor-Related Regulatory Networks Based on Bioinformatics Analysis and Validation in Hepatocellular Carcinoma. BIOMED RESEARCH INTERNATIONAL 2018; 2018:1431396. [PMID: 30228980 PMCID: PMC6136478 DOI: 10.1155/2018/1431396] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/03/2018] [Accepted: 07/25/2018] [Indexed: 02/07/2023]
Abstract
Hepatocellular carcinoma (HCC) accounts for a significant proportion of liver cancer, which has become the second most common cause of cancer-related mortality worldwide. To investigate the potential mechanisms of invasion and progression of HCC, bioinformatics analysis and validation by qRT-PCR were performed. We found 237 differentially expressed genes (DEGs) including EGR1, FOS, and FOSB, which were three cancer-related transcription factors. Subsequently, we constructed TF-gene network and miRNA-TF-mRNA network based on data obtained from mRNA and miRNA expression profiles for analysis of HCC. We found that 42 key genes from the TF-gene network including EGR1, FOS, and FOSB were most enriched in the p53 signaling pathway. The qRT-PCR data confirmed that mRNA levels of EGR1, FOS, and FOSB all were decreased in HCC tissues. In addition, we confirmed that the mRNA levels of CCNB1, CCNB2, and CHEK1, three key markers of the p53 signaling pathway, were all increased in HCC tissues by bioinformatics analysis and qRT-PCR validation. Therefore, we speculated that miR-181a-5p, which was upregulated in HCC tissues, could regulate FOS and EGR1 to promote the invasion and progression of HCC by p53 signaling pathway. Overall, the study provides support for the possible mechanisms of progression in HCC.
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Affiliation(s)
- Shui Liu
- Department of Hepatobiliary and Pancreatic Surgery, The Second Hospital of Jilin University, Changchun 130041, China
- Jilin Engineering Laboratory for Translational Medicine of Hepatobiliary and Pancreatic Diseases, The Second Hospital of Jilin University, Changchun 130041, China
| | - Xiaoxiao Yao
- Department of Hepatobiliary and Pancreatic Surgery, The Second Hospital of Jilin University, Changchun 130041, China
- Jilin Engineering Laboratory for Translational Medicine of Hepatobiliary and Pancreatic Diseases, The Second Hospital of Jilin University, Changchun 130041, China
| | - Dan Zhang
- Department of Hepatobiliary and Pancreatic Surgery, The Second Hospital of Jilin University, Changchun 130041, China
- Jilin Engineering Laboratory for Translational Medicine of Hepatobiliary and Pancreatic Diseases, The Second Hospital of Jilin University, Changchun 130041, China
| | - Jiyao Sheng
- Department of Hepatobiliary and Pancreatic Surgery, The Second Hospital of Jilin University, Changchun 130041, China
- Jilin Engineering Laboratory for Translational Medicine of Hepatobiliary and Pancreatic Diseases, The Second Hospital of Jilin University, Changchun 130041, China
| | - Xin Wen
- The Second Hospital of Jilin University, Changchun 130041, China
| | - Qingyu Wang
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun 130041, China
| | - Gaoyang Chen
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun 130041, China
| | - Zhaoyan Li
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun 130041, China
| | - Zhenwu Du
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun 130041, China
- Research Center of Second Clinical College, Jilin University, Changchun 130041, China
| | - Xuewen Zhang
- Department of Hepatobiliary and Pancreatic Surgery, The Second Hospital of Jilin University, Changchun 130041, China
- Jilin Engineering Laboratory for Translational Medicine of Hepatobiliary and Pancreatic Diseases, The Second Hospital of Jilin University, Changchun 130041, China
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12
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Schuler F, Weiss JG, Lindner SE, Lohmüller M, Herzog S, Spiegl SF, Menke P, Geley S, Labi V, Villunger A. Checkpoint kinase 1 is essential for normal B cell development and lymphomagenesis. Nat Commun 2017; 8:1697. [PMID: 29167438 PMCID: PMC5700047 DOI: 10.1038/s41467-017-01850-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 10/20/2017] [Indexed: 12/20/2022] Open
Abstract
Checkpoint kinase 1 (CHK1) is critical for intrinsic cell cycle control and coordination of cell cycle progression in response to DNA damage. Despite its essential function, CHK1 has been identified as a target to kill cancer cells and studies using Chk1 haploinsufficient mice initially suggested a role as tumor suppressor. Here, we report on the key role of CHK1 in normal B-cell development, lymphomagenesis and cell survival. Chemical CHK1 inhibition induces BCL2-regulated apoptosis in primary as well as malignant B-cells and CHK1 expression levels control the timing of lymphomagenesis in mice. Moreover, total ablation of Chk1 in B-cells arrests their development at the pro-B cell stage, a block that, surprisingly, cannot be overcome by inhibition of mitochondrial apoptosis, as cell cycle arrest is initiated as an alternative fate to limit the spread of damaged DNA. Our findings define CHK1 as essential in B-cell development and potent target to treat blood cancer.
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Affiliation(s)
- Fabian Schuler
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Innrain 80, A-6020, Innsbruck, Austria
| | - Johannes G Weiss
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Innrain 80, A-6020, Innsbruck, Austria
| | - Silke E Lindner
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Innrain 80, A-6020, Innsbruck, Austria
| | - Michael Lohmüller
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Innrain 80, A-6020, Innsbruck, Austria
| | - Sebastian Herzog
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Innrain 80, A-6020, Innsbruck, Austria
| | - Simon F Spiegl
- Division of Molecular Pathophysiology, Biocenter, Medical University of Innsbruck, Innrain 80, A-6020, Innsbruck, Austria
| | - Philipp Menke
- Division of Molecular Pathophysiology, Biocenter, Medical University of Innsbruck, Innrain 80, A-6020, Innsbruck, Austria
| | - Stephan Geley
- Division of Molecular Pathophysiology, Biocenter, Medical University of Innsbruck, Innrain 80, A-6020, Innsbruck, Austria
| | - Verena Labi
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Innrain 80, A-6020, Innsbruck, Austria
| | - Andreas Villunger
- Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Innrain 80, A-6020, Innsbruck, Austria. .,Tyrolean Cancer Research Institute, Innrain 66, A-6020, Innsbruck, Austria.
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Chk1 Promotes DNA Damage Response Bypass following Oxidative Stress in a Model of Hydrogen Peroxide-Associated Ulcerative Colitis through JNK Inactivation and Chromatin Binding. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:9303158. [PMID: 28751935 PMCID: PMC5478872 DOI: 10.1155/2017/9303158] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/14/2017] [Accepted: 04/11/2017] [Indexed: 12/20/2022]
Abstract
Dysregulation of c-Jun N-terminal kinase (JNK) activation promoted DNA damage response bypass and tumorigenesis in our model of hydrogen peroxide-associated ulcerative colitis (UC) and in patients with quiescent UC (QUC), UC-related dysplasia, and UC-related carcinoma (UC-CRC), thereby adapting to oxidative stress. In the UC model, we have observed features of oncogenic transformation: increased proliferation, undetected DNA damage, and apoptosis resistance. Here, we show that Chk1 was downregulated but activated in the acute and quiescent chronic phases. In both phases, Chk1 was linked to DNA damage response bypass by suppressing JNK activation following oxidative stress, promoting cell cycle progression despite DNA damage. Simultaneously, activated Chk1 was bound to chromatin. This triggered histone acetylation and the binding of histone acetyltransferases and transcription factors to chromatin. Thus, chromatin-immobilized activated Chk1 executed a dual function by suppressing DNA damage response and simultaneously inducing chromatin modulation. This caused undetected DNA damage and increased cellular proliferation through failure to transmit the appropriate DNA damage signal. Findings in vitro were corroborated by chromatin accumulation of activated Chk1, Ac-H3, Ac-H4, and c-Jun in active UC (AUC) in vivo. Targeting chromatin-bound Chk1, GCN5, PCAF, and p300/CBP could be a novel therapeutic strategy to prevent UC-related tumor progression.
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14
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Abstract
Cancer is characterized by uncontrolled tumour cell proliferation resulting from aberrant activity of various cell cycle proteins. Therefore, cell cycle regulators are considered attractive targets in cancer therapy. Intriguingly, animal models demonstrate that some of these proteins are not essential for proliferation of non-transformed cells and development of most tissues. By contrast, many cancers are uniquely dependent on these proteins and hence are selectively sensitive to their inhibition. After decades of research on the physiological functions of cell cycle proteins and their relevance for cancer, this knowledge recently translated into the first approved cancer therapeutic targeting of a direct regulator of the cell cycle. In this Review, we focus on proteins that directly regulate cell cycle progression (such as cyclin-dependent kinases (CDKs)), as well as checkpoint kinases, Aurora kinases and Polo-like kinases (PLKs). We discuss the role of cell cycle proteins in cancer, the rationale for targeting them in cancer treatment and results of clinical trials, as well as the future therapeutic potential of various cell cycle inhibitors.
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Affiliation(s)
- Tobias Otto
- Department of Cancer Biology, Dana-Farber Cancer Institute and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02215, USA
- Department of Internal Medicine III, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Piotr Sicinski
- Department of Cancer Biology, Dana-Farber Cancer Institute and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02215, USA
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15
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Sarmento LM, Barata JT. CHK1 and replicative stress in T-cell leukemia: Can an irreverent tumor suppressor end up playing the oncogene? Adv Biol Regul 2016; 60:115-121. [PMID: 26527132 DOI: 10.1016/j.jbior.2015.10.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 10/19/2015] [Accepted: 10/20/2015] [Indexed: 06/05/2023]
Abstract
Replicative stress (RS) is a cell-intrinsic phenomenon enhanced by oncogenic transformation. Checkpoint kinase 1 (CHK1) is a key component of the ATR-dependent DNA damage response pathway that protects cells from RS by preventing replication fork collapse and activating homologous DNA repair. Taking this knowledge into account, one would predict CHK1 behaves strictly as a tumor suppressor. However, the reality seems far more complex. CHEK1 loss-of-function mutations have not been found in human tumors, and transgenic expression of Chek1 in mice promotes oncogene-induced transformation through RS inhibition. Moreover, CHK1 is overexpressed in various human cancers and CHK1 inhibitors have been developed as sensitizers to enhance the cytotoxicity of DNA damage-inducing chemotherapies. Here, we summarize the literature on the involvement of CHK1 in cancer progression, including our recent observation that CHK1 sustains T-cell acute lymphoblastic leukemia (T-ALL) cell viability. We also debate the importance of identifying patients that could benefit the most from treatment with CHK1 inhibitors, taking T-ALL as a model, and propose possible markers of therapeutic response.
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Affiliation(s)
- Leonor M Sarmento
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - João T Barata
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal.
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16
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Ajiro M, Jia R, Wang RH, Deng CX, Zheng ZM. Adapted Resistance to the Knockdown Effect of shRNA-Derived Srsf3 siRNAs in Mouse Littermates. Int J Biol Sci 2015; 11:1248-56. [PMID: 26435690 PMCID: PMC4582148 DOI: 10.7150/ijbs.13011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 07/29/2015] [Indexed: 11/05/2022] Open
Abstract
Gene silencing techniques are widely used to control gene expression and have potential for RNAi-based therapeutics. In this report, transgenic mouse lines were created for conditional knockdown of Srsf3 (SRp20) expression in liver and mammary gland tissues by expressing Srsf3-specific shRNAs driven by a U6 promoter. Although a small portion of the transgenic mouse littermates were found to produce siRNAs in the targeted tissues, most of the transgenic littermates at two months of age failed to display a knockdown phenotype of Srsf3 expression in their liver and mammary gland tissues where an abundant level of Srsf3 siRNAs remained. We saw only one of four mice with liver/mammary gland expressing Srsf3 siRNA displayed a suppressed level of Srsf3 protein, but not the mRNA. Data indicate that the host resistance to a gene-specific siRNA targeting an essential gene transcript can be developed in animals, presumably as a physiological necessity to cope with the hostile perturbation.
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Affiliation(s)
- Masahiko Ajiro
- 1. Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
| | - Rong Jia
- 1. Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA ; 3. Wuhan University School of Stomatology, Wuhan, Hubei, China
| | - Rui-Hong Wang
- 2. Genetics of Development and Disease Branch, 10/9N105, National Institute of Diabetes, Digestive and Kidney Diseases, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, MD 20892, USA. ; 4. Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Chu-Xia Deng
- 2. Genetics of Development and Disease Branch, 10/9N105, National Institute of Diabetes, Digestive and Kidney Diseases, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, MD 20892, USA. ; 4. Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Zhi-Ming Zheng
- 1. Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
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Manic G, Obrist F, Sistigu A, Vitale I. Trial Watch: Targeting ATM-CHK2 and ATR-CHK1 pathways for anticancer therapy. Mol Cell Oncol 2015; 2:e1012976. [PMID: 27308506 PMCID: PMC4905354 DOI: 10.1080/23723556.2015.1012976] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 01/25/2015] [Accepted: 01/26/2015] [Indexed: 02/08/2023]
Abstract
The ataxia telangiectasia mutated serine/threonine kinase (ATM)/checkpoint kinase 2 (CHEK2, best known as CHK2) and the ATM and Rad3-related serine/threonine kinase (ATR)/CHEK1 (best known as CHK1) cascades are the 2 major signaling pathways driving the DNA damage response (DDR), a network of processes crucial for the preservation of genomic stability that act as a barrier against tumorigenesis and tumor progression. Mutations and/or deletions of ATM and/or CHK2 are frequently found in tumors and predispose to cancer development. In contrast, the ATR-CHK1 pathway is often upregulated in neoplasms and is believed to promote tumor growth, although some evidence indicates that ATR and CHK1 may also behave as haploinsufficient oncosuppressors, at least in a specific genetic background. Inactivation of the ATM-CHK2 and ATR-CHK1 pathways efficiently sensitizes malignant cells to radiotherapy and chemotherapy. Moreover, ATR and CHK1 inhibitors selectively kill tumor cells that present high levels of replication stress, have a deficiency in p53 (or other DDR players), or upregulate the ATR-CHK1 module. Despite promising preclinical results, the clinical activity of ATM, ATR, CHK1, and CHK2 inhibitors, alone or in combination with other therapeutics, has not yet been fully demonstrated. In this Trial Watch, we give an overview of the roles of the ATM-CHK2 and ATR-CHK1 pathways in cancer initiation and progression, and summarize the results of clinical studies aimed at assessing the safety and therapeutic profile of regimens based on inhibitors of ATR and CHK1, the only 2 classes of compounds that have so far entered clinics.
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Affiliation(s)
| | - Florine Obrist
- Université Paris-Sud/Paris XI; Le Kremlin-Bicêtre, France
- INSERM, UMRS1138; Paris, France
- Equipe 11 labelisée par la Ligue Nationale contre le Cancer; Centre de Recherche des Cordeliers; Paris, France
- Gustave Roussy Cancer Campus; Villejuif, France
| | | | - Ilio Vitale
- Regina Elena National Cancer Institute; Rome, Italy
- Department of Biology, University of Rome “TorVergata”; Rome, Italy
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18
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Abstract
Genome instability is a hallmark of cancer, and DNA replication is the most vulnerable cellular process that can lead to it. Any condition leading to high levels of DNA damage will result in replication stress, which is a source of genome instability and a feature of pre-cancerous and cancerous cells. Therefore, understanding the molecular basis of replication stress is crucial to the understanding of tumorigenesis. Although a negative aspect of replication stress is its prominent role in tumorigenesis, a positive aspect is that it provides a potential target for cancer therapy. In this Review, we discuss the link between persistent replication stress and tumorigenesis, with the goal of shedding light on the mechanisms underlying the initiation of an oncogenic process, which should open up new possibilities for cancer diagnostics and treatment.
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Affiliation(s)
- Hélène Gaillard
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Av. Américo Vespucio s/n, Sevilla 41092, Spain
| | - Tatiana García-Muse
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Av. Américo Vespucio s/n, Sevilla 41092, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Av. Américo Vespucio s/n, Sevilla 41092, Spain
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Abstract
In 2007, three scientists, Drs. Mario R. Capecchi, Martin J. Evans, and Oliver Smithies, received the Nobel Prize in Physiology or Medicine for their contributions of introducing specific gene modifications into mice. This technology, commonly referred to as gene targeting or knockout, has proven to be a powerful means for precisely manipulating the mammalian genome and has generated great impacts on virtually all phases of mammalian biology and basic biomedical research. Of note, germline mutations of many genes, especially tumor suppressors, often result in lethality during embryonic development or at developmental stages before tumor formation. This obstacle has been effectively overcome by the use of conditional knockout technology in conjunction with Cre-LoxP- or Flp-Frt-mediated temporal and/or spatial systems to generate genetic switches for precise DNA recombination. Currently, numerous conditional knockout mouse models have been successfully generated and applied in studying tumor initiation, progression, and metastasis. This review summarizes some conditional mutant mouse models that are widely used in cancer research and our understanding of the possible mechanisms underlying tumorigenesis.
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Affiliation(s)
- Chu-Xia Deng
- Genetics of Development and Disease Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
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Greenow KR, Clarke AR, Williams GT, Jones R. Wnt-driven intestinal tumourigenesis is suppressed by Chk1 deficiency but enhanced by conditional haploinsufficiency. Oncogene 2014; 33:4089-96. [PMID: 24037525 DOI: 10.1038/onc.2013.371] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 05/17/2013] [Accepted: 06/07/2013] [Indexed: 12/11/2022]
Abstract
Chk1 is essential in maintaining genomic stability due to its role in cell cycle regulation. Several recent studies have indicated that the abrogation of checkpoints in tumourigenesis through the inhibition of Chk1 may be of therapeutic value. To further investigate the role of Chk1 in the mouse small intestine and its potential role as a therapy for colorectal cancer, we simultaneously deleted Chk1 and Apc in the mouse small intestine. We found that homozygous loss of Chk1 is not compatible with Wnt-driven proliferation and resulted in the suppression of Wnt-driven tumourigenesis in the mouse small intestine. In contrast, heterozygous loss of Chk1 in a Wnt-driven background resulted in an increase in DNA damage and apoptosis and accelerated both tumour development and progression.
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Affiliation(s)
- K R Greenow
- Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - A R Clarke
- Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - G T Williams
- School of Medicine, Cardiff University, Cardiff, UK
| | - R Jones
- Cardiff School of Biosciences, Cardiff University, Cardiff, UK
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21
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Schulze J, Lopez-Contreras AJ, Uluçkan Ö, Graña-Castro O, Fernandez-Capetillo O, Wagner EF. Fos-dependent induction of Chk1 protects osteoblasts from replication stress. Cell Cycle 2014; 13:1980-6. [PMID: 24762558 DOI: 10.4161/cc.28923] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Stable Fos expression in the osteoblast lineage results in the development of osteosarcomas (OS) in mice, yet the underlying mechanisms are poorly understood. Using a genetic system in which Fos expression can be induced in osteoblasts in a doxycycline-dependent manner and through subsequent RNA sequencing and gene set enrichment analysis, we were able to identify novel transcriptional targets of Fos in osteoblasts. These included a distinct activation of cellular response toward replication stress (RS), exemplified by a Fos-dependent induction of the RS-suppressing Chk1 kinase. Importantly, Fos expression protects osteoblasts from RS and DNA damage likely through upregulation of Chk1 and facilitates transformation by Ras/E1A oncogenes. These data reveal a novel function of Fos in safeguarding genome stability during replication, which is particularly relevant in conditions of oncogene-induced S-phase entry.
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Affiliation(s)
- Jochen Schulze
- BBVA Foundation-CNIO Cancer Cell Biology Programme; Spanish National Cancer Research Centre (CNIO); Madrid, Spain
| | | | - Özge Uluçkan
- BBVA Foundation-CNIO Cancer Cell Biology Programme; Spanish National Cancer Research Centre (CNIO); Madrid, Spain
| | - Osvaldo Graña-Castro
- Bioinformatics Unit; Spanish National Cancer Research Centre (CNIO); Madrid, Spain
| | | | - Erwin F Wagner
- BBVA Foundation-CNIO Cancer Cell Biology Programme; Spanish National Cancer Research Centre (CNIO); Madrid, Spain
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22
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Yang X, Xu W, Hu Z, Zhang Y, Xu N. Chk1 is required for the metaphase-anaphase transition via regulating the expression and localization of Cdc20 and Mad2. Life Sci 2014; 106:12-8. [PMID: 24747134 DOI: 10.1016/j.lfs.2014.04.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 03/31/2014] [Accepted: 04/07/2014] [Indexed: 11/16/2022]
Abstract
AIMS The checkpoint kinase 1 (Chk1) functions not only in genotoxic stresses but also in normal cell cycle progression, particularly in the initiation, progression and fidelity of unperturbed mitosis. In this study, we investigated the role of Chk1 in regulating the metaphase-anaphase transition in mammalian cells. MAIN METHODS The mitotic progression was monitored by flow cytometry analysis. The levels of cyclin B1, Cdc20 and Mad2 were measured by Western blotting. Metaphase chromosome alignment and the subcellular localization of Cdc20 and Mad2 were analyzed by immunofluorescence and confocal microscopy. KEY FINDINGS Cyclin B1 degradation and the metaphase-anaphase transition were severely blocked by Chk1 siRNA. Depletion of Chk1 induced chromosome alignment defect in metaphase cells. The kinetochore localization of Cdc20, Mad2 was disrupted in Chk1 depleted cells. Chk1 abrogation also dramatically reduced the protein expression levels of Cdc20 and Mad2. SIGNIFICANCE These results strongly suggest that Chk1 is required for the metaphase-anaphase transition via regulating the subcellular localization and the expression of Cdc20 and Mad2.
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Affiliation(s)
- Xiaoyun Yang
- School of Life Sciences, Tsinghua University, Beijing 100084, PR China; Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong Province, PR China
| | - Wei Xu
- School of Life Sciences, Tsinghua University, Beijing 100084, PR China; Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong Province, PR China
| | - Zuowei Hu
- Department of Clinical Oncology, Wuhan No. 1 Hospital, Wuhan, Hubei Province, PR China
| | - Yaou Zhang
- Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong Province, PR China
| | - Naihan Xu
- Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong Province, PR China.
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23
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Donehower LA. Insights into Wild-Type and Mutant p53 Functions Provided by Genetically Engineered Mice. Hum Mutat 2014; 35:715-27. [DOI: 10.1002/humu.22507] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/02/2014] [Indexed: 01/17/2023]
Affiliation(s)
- Lawrence A. Donehower
- Departments of Molecular Virology and Microbiology, Molecular and Cellular Biology, and Pediatrics; Baylor College of Medicine; Houston Texas 77030
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24
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Abstract
DNA damage response genes play vital roles in the maintenance of a healthy genome. Defects in cell cycle checkpoint and DNA repair genes, especially mutation or aberrant downregulation, are associated with a wide spectrum of human disease, including a predisposition to the development of neurodegenerative conditions and cancer. On the other hand, upregulation of DNA damage response and repair genes can also cause cancer, as well as increase resistance of cancer cells to DNA damaging therapy. In recent years, it has become evident that many of the genes involved in DNA damage repair have additional roles in tumorigenesis, most prominently by acting as transcriptional (co-)factors. Although defects in these genes are causally connected to tumor initiation, their role in tumor progression is more controversial and it seems to depend on tumor type. In some tumors like melanoma, cell cycle checkpoint/DNA repair gene upregulation is associated with tumor metastasis, whereas in a number of other cancers the opposite has been observed. Several genes that participate in the DNA damage response, such as RAD9, PARP1, BRCA1, ATM and TP53 have been associated with metastasis by a number of in vitro biochemical and cellular assays, by examining human tumor specimens by immunohistochemistry or by DNA genome-wide gene expression profiling. Many of these genes act as transcriptional effectors to regulate other genes implicated in the pathogenesis of cancer. Furthermore, they are aberrantly expressed in numerous human tumors and are causally related to tumorigenesis. However, whether the DNA damage repair function of these genes is required to promote metastasis or another activity is responsible (e.g., transcription control) has not been determined. Importantly, despite some compelling in vitro evidence, investigations are still needed to demonstrate the role of cell cycle checkpoint and DNA repair genes in regulating metastatic phenotypes in vivo.
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Affiliation(s)
- Constantinos G. Broustas
- Center for Radiological Research, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Howard B. Lieberman
- Center for Radiological Research, Columbia University College of Physicians and Surgeons, New York, New York 10032
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032
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25
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Khanna A, Kauko O, Böckelman C, Laine A, Schreck I, Partanen JI, Szwajda A, Bormann S, Bilgen T, Helenius M, Pokharel YR, Pimanda J, Russel MR, Haglund C, Cole KA, Klefström J, Aittokallio T, Weiss C, Ristimäki A, Visakorpi T, Westermarck J. Chk1 targeting reactivates PP2A tumor suppressor activity in cancer cells. Cancer Res 2013; 73:6757-69. [PMID: 24072747 DOI: 10.1158/0008-5472.can-13-1002] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Checkpoint kinase Chk1 is constitutively active in many cancer cell types and new generation Chk1 inhibitors show marked antitumor activity as single agents. Here we present a hitherto unrecognized mechanism that contributes to the response of cancer cells to Chk1-targeted therapy. Inhibiting chronic Chk1 activity in cancer cells induced the tumor suppressor activity of protein phosphatase protein phosphatase 2A (PP2A), which by dephosphorylating MYC serine 62, inhibited MYC activity and impaired cancer cell survival. Mechanistic investigations revealed that Chk1 inhibition activated PP2A by decreasing the transcription of cancerous inhibitor of PP2A (CIP2A), a chief inhibitor of PP2A activity. Inhibition of cancer cell clonogenicity by Chk1 inhibition could be rescued in vitro either by exogenous expression of CIP2A or by blocking the CIP2A-regulated PP2A complex. Chk1-mediated CIP2A regulation was extended in tumor models dependent on either Chk1 or CIP2A. The clinical relevance of CIP2A as a Chk1 effector protein was validated in several human cancer types, including neuroblastoma, where CIP2A was identified as an NMYC-independent prognostic factor. Because the Chk1-CIP2A-PP2A pathway is driven by DNA-PK activity, functioning regardless of p53 or ATM/ATR status, our results offer explanative power for understanding how Chk1 inhibitors mediate single-agent anticancer efficacy. Furthermore, they define CIP2A-PP2A status in cancer cells as a pharmacodynamic marker for their response to Chk1-targeted therapy.
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Affiliation(s)
- Anchit Khanna
- Authors' Affiliations: Institute of Biomedical Technology and BioMediTech, University of Tampere and Tampere University Hospital; Tampere Graduate Program in Biomedicine and Biotechnology (TGPBB), University of Tampere, Tampere; Turku Centre for Biotechnology, University of Turku and Åbo Akademi University; Department of Pathology, University of Turku; Turku Doctoral Program of Biomedical Sciences (TuBS), Turku; Department of Pathology, HUSLAB and Haartman Institute, Helsinki University, Central Hospital and University of Helsinki; University of Helsinki Institute of Biomedicine and Genome-Scale Biology Research Program; Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland; Karlsruhe Institute of Technology, Campus North, Institute of Toxicology and Genetics, Karlsruhe, Germany; Adult Cancer Program, Lowy Cancer Centre and Prince of Wales Hospital, UNSW Medicine, University of New South Wales, Sydney, Australia; Department of Medical Biology and Genetics, Faculty of Medicine, Akdeniz University, Antalya, Turkey; Division of Oncology, Children's Hospital of Philadelphia; and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia
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26
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Sproul CD, Rao S, Ibrahim JG, Kaufmann WK, Cordeiro-Stone M. Is activation of the intra-S checkpoint in human fibroblasts an important factor in protection against UV-induced mutagenesis? Cell Cycle 2013; 12:3555-63. [PMID: 24091629 DOI: 10.4161/cc.26590] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The ATR/CHK1-dependent intra-S checkpoint inhibits replicon initiation and replication fork progression in response to DNA damage caused by UV (UV) radiation. It has been proposed that this signaling cascade protects against UV-induced mutations by reducing the probability that damaged DNA will be replicated before it can be repaired. Normal human fibroblasts (NHF) were depleted of ATR or CHK1, or treated with the CHK1 kinase inhibitor TCS2312, and the UV-induced mutation frequency at the HPRT locus was measured. Despite clear evidence of S-phase checkpoint abrogation, neither ATR/CHK1 depletion nor CHK1 inhibition caused an increase in the UV-induced HPRT mutation frequency. These results question the premise that the UV-induced intra-S checkpoint plays a prominent role in protecting against UV-induced mutagenesis.
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Affiliation(s)
- Christopher D Sproul
- Curriculum in Toxicology; University of North Carolina-Chapel Hill; Chapel Hill, NC USA
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27
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Zhang Y, Hunter T. Roles of Chk1 in cell biology and cancer therapy. Int J Cancer 2013; 134:1013-23. [PMID: 23613359 DOI: 10.1002/ijc.28226] [Citation(s) in RCA: 302] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 04/11/2013] [Indexed: 01/05/2023]
Abstract
The evolutionally conserved DNA damage response (DDR) and cell cycle checkpoints preserve genome integrity. Central to these genome surveillance pathways is a protein kinase, Chk1. DNA damage induces activation of Chk1, which then transduces the checkpoint signal and facilitates cell cycle arrest and DNA damage repair. Significant progress has been made recently toward our understanding of Chk1 regulation and its implications in cancer etiology and therapy. Specifically, a model that involves both spatiotemporal and conformational changes of proteins has been proposed for Chk1 activation. Further, emerging evidence suggests that Chk1 does not appear to be a tumor suppressor; instead, it promotes tumor growth and may contribute to anticancer therapy resistance. Recent data from our laboratory suggest that activating, but not inhibiting, Chk1 in the absence of chemotherapy might represent an innovative approach to suppress tumor growth. These findings suggest unique regulation of Chk1 in cell biology and cancer etiology, pointing to novel strategies for targeting Chk1 in cancer therapy.
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Affiliation(s)
- Youwei Zhang
- Department of Pharmacology, Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH
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28
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Patil M, Pabla N, Dong Z. Checkpoint kinase 1 in DNA damage response and cell cycle regulation. Cell Mol Life Sci 2013; 70:4009-21. [PMID: 23508805 DOI: 10.1007/s00018-013-1307-3] [Citation(s) in RCA: 190] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/28/2013] [Accepted: 02/18/2013] [Indexed: 12/19/2022]
Abstract
Originally identified as a mediator of DNA damage response (DDR), checkpoint kinase 1 (Chk1) has a broader role in checkpoint activation in DDR and normal cell cycle regulation. Chk1 activation involves phosphorylation at conserved sites. However, recent work has identified a splice variant of Chk1, which may regulate Chk1 in both DDR and normal cell cycle via molecular interaction. Upon activation, Chk1 phosphorylates a variety of substrate proteins, resulting in the activation of DNA damage checkpoints, cell cycle arrest, DNA repair, and/or cell death. Chk1 and its related signaling may be an effective therapeutic target in diseases such as cancer.
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Affiliation(s)
- Mallikarjun Patil
- Department of Cellular Biology and Anatomy, Georgia Regents University and Charlie Norwood VA Medical Center, 1459 Laney Walker Blvd., Augusta, GA, 30912, USA
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29
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Palii SS, Cui Y, Innes CL, Paules RS. Dissecting cellular responses to irradiation via targeted disruptions of the ATM-CHK1-PP2A circuit. Cell Cycle 2013; 12:1105-18. [PMID: 23462183 DOI: 10.4161/cc.24127] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Exposure of proliferating cells to genotoxic stresses activates a cascade of signaling events termed the DNA damage response (DDR). The DDR preserves genetic stability by detecting DNA lesions, activating cell cycle checkpoints and promoting DNA damage repair. The phosphoinositide 3-kinase-related kinases (PIKKs) ataxia telangiectasia-mutated (ATM), ATM and Rad 3-related kinase (ATR) and DNA-dependent protein kinase (DNA-PK) are crucial for sensing lesions and signal transduction. The checkpoint kinase 1 (CHK1) is a traditional ATR target involved in DDR and normal cell cycle progression and represents a pharmacological target for anticancer regimens. This study employed cell lines stably depleted for CHK1, ATM or both for dissecting cross-talk and compensatory effects on G(2)/M checkpoint in response to ionizing radiation (IR). We show that a 90% depletion of CHK1 renders cells radiosensitive without abrogating their IR-mediated G(2)/M checkpoint arrest. ATM phosphorylation is enhanced in CHK1-deficient cells compared with their wild-type counterparts. This correlates with lower nuclear abundance of the PP2A catalytic subunit in CHK1-depleted cells. Stable depletion of CHK1 in an ATM-deficient background showed only a 50% reduction from wild-type CHK1 protein expression levels and resulted in an additive attenuation of the G(2)/M checkpoint response compared with the individual knockdowns. ATM inhibition and 90% CHK1 depletion abrogated the early G(2)/M checkpoint and precluded the cells from mounting an efficient compensatory response to IR at later time points. Our data indicates that dual targeting of ATM and CHK1 functionalities disrupts the compensatory response to DNA damage and could be exploited for developing efficient anti-neoplastic treatments.
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Affiliation(s)
- Stela S Palii
- Environmental Stress and Cancer Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
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30
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Chilà R, Celenza C, Lupi M, Damia G, Carrassa L. Chk1-Mad2 interaction: a crosslink between the DNA damage checkpoint and the mitotic spindle checkpoint. Cell Cycle 2013; 12:1083-90. [PMID: 23454898 DOI: 10.4161/cc.24090] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Chk1 is implicated in several checkpoints of the cell cycle acting as a key player in the signal transduction pathway activated in response to DNA damage and crucial for the maintenance of genomic stability. Chk1 also plays a role in the mitotic spindle checkpoint, which ensures the fidelity of mitotic segregation during mitosis, preventing chromosomal instability and aneuploidy. Mad2 is one of the main mitotic checkpoint components and also exerts a role in the cellular response to DNA damage. To investigate a possible crosslink existing between Chk1 and Mad2, we studied Mad2 protein levels after Chk1 inhibition either by specific siRNAs or by a specific and selective Chk1 inhibitor (PF-00477736), and we found that after Chk1 inhibition, Mad2 protein levels decrease only in tumor cells sensitive to Chk1 depletion. We then mapped six Chk1's phosphorylatable sites on Mad2 protein, and found that Chk1 is able to phosphorylate Mad2 in vitro on more than one site, while it is incapable of phoshorylating the Mad2 form mutated on all six phosphorylatable sites. Moreover our studies demonstrate that Chk1 co-localizes and physically associates with Mad2 in cells both under unstressed conditions and after DNA damage, thus providing new and interesting evidence on Chk1 and Mad2 crosstalk in the DNA damage checkpoint and in the mitotic spindle checkpoint.
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Affiliation(s)
- Rosaria Chilà
- Laboratory of Molecular Pharmacology, Department of Oncology, IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
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31
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Chen G, Gulbranson DR, Yu P, Hou Z, Thomson JA. Thermal stability of fibroblast growth factor protein is a determinant factor in regulating self-renewal, differentiation, and reprogramming in human pluripotent stem cells. Stem Cells 2012; 30:623-30. [PMID: 22213113 DOI: 10.1002/stem.1021] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Fibroblast growth factor (FGF), transforming growth factor (TGF)/Nodal, and Insulin/insulin-like growth factor (IGF) signaling pathways are sufficient to maintain human embryonic stem cells (ESCs) and induced pluripotent stem cells in a proliferative, undifferentiated state. Here, we show that only a few FGF family members (FGF2, FGF4, FGF6, and FGF9) are able to sustain strong extracellular-signal-regulated kinase (ERK) phosphorylation and NANOG expression levels in human ESCs. Surprisingly, FGF1, which is reported to target the same set of receptors as FGF2, fails to sustain ERK phosphorylation and NANOG expression under standard culture conditions. We find that the failure of FGF1 to sustain ES is due to thermal instability of the wild-type protein, not receptor specificity, and that a mutated thermal-stable FGF1 sustains human ESCs and supports both differentiation and reprogramming protocols.
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Affiliation(s)
- Guokai Chen
- Morgridge Institute for Research, Madison, Wisconsin, USA
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32
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Cell cycle- and DNA repair pathway-specific effects of apoptosis on tumor suppression. Proc Natl Acad Sci U S A 2012; 109:9953-8. [PMID: 22670056 DOI: 10.1073/pnas.1120476109] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The DNA damage response comprises DNA repair, cell-cycle checkpoint control, and DNA damage-induced apoptosis that collectively promote genomic integrity and suppress tumorigenesis. Previously, we have shown that the Chk2 kinase functions independently of the Mre11 complex (Mre11, Rad50, and Nbs1) and ATM in apoptosis and suppresses tumorigenesis resulting from hypomorphic alleles of Mre11 or Nbs1. Based on this work, we have proposed that Chk2 limits the oncogenic potential of replication-associated DNA damage. Here we further address the role of Chk2 and damage-induced apoptosis in suppressing the oncogenic potential of chromosome breaks. We show that loss of Chk2 or a mutation in p53 (R172P), which selectively impairs its function in apoptosis, rescued the lethality of mice lacking Lig4, a ligase required for nonhomologous end-joining (NHEJ) repair of DNA double-strand breaks in G0/G1. In contrast to Lig4(-/-)p53(-/-) mice, Lig4(-/-)Chk2(-/-) and Lig4(-/-)p53(R172P/R172P) mice were not prone to organ-specific, rapid tumorigenesis. Although the severe NHEJ deficiency of Lig4(-/-) was a less potent initiator of tumorigenesis in the p53(R172P/R172P) and Chk2(-/-) backgrounds, where p53 cell-cycle functions are largely intact, even mild defects in the intra-S and G2/M checkpoints caused by mutations in Nbs1 are sufficient to influence malignancy in p53(R172P/R172P) mice. We conclude that the oncogenic potential of double-strand breaks resulting from NHEJ deficiency is highly restricted by nonapoptotic functions of p53, such as the G1/S checkpoint or senescence, suggesting that the particular facets of the DNA damage response required for tumor suppression are dictated by the proliferative status of the tumor-initiating cell.
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Wilsker D, Chung JH, Bunz F. Chk1 suppresses bypass of mitosis and tetraploidization in p53-deficient cancer cells. Cell Cycle 2012; 11:1564-72. [PMID: 22433954 DOI: 10.4161/cc.19944] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Many cancer cells are unable to maintain a numerically stable chromosome complement. It is well established that aberrant cell division can generate progeny with increased ploidy, but the genetic factors required for maintenance of diploidy are not well understood. Using an isogenic model system derived by gene targeting, we examined the role of Chk1 in p53-proficient and -deficient cancer cells. Targeted inactivation of a single CHK1 allele in stably diploid cells caused an elevated frequency of mitotic bypass if p53 was naturally mutated or experimentally disrupted by homologous recombination. CHK1-haploinsufficient, p53-deficient cells frequently underwent sequential rounds of DNA synthesis without an intervening mitosis. These aberrant cell cycles resulted in whole-genome endoreduplication and tetraploidization. The unscheduled bypass of mitosis could be suppressed by targeted reversion of a p53 mutation or by exogenous expression of Cdk1. In contrast, the number of tetraploid cells was not increased in isogenic cell populations that harbor hypomorphic ATR mutations, suggesting that suppression of unscheduled mitotic bypass is a distinct function of Chk1. These results are consistent with a recently described role for Chk1 in promoting the expression of genes that promote cell cycle transitions and demonstrate how Chk1 might prevent tetraploidization during the cancer cell cycle.
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Affiliation(s)
- Deborah Wilsker
- Molecular Radiation Therapeutics Branch, National Cancer Institute, Frederick, MD, USA
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Tho LM, Libertini S, Rampling R, Sansom O, Gillespie DA. Chk1 is essential for chemical carcinogen-induced mouse skin tumorigenesis. Oncogene 2012; 31:1366-75. [PMID: 21804609 DOI: 10.1038/onc.2011.326] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 06/26/2011] [Accepted: 06/26/2011] [Indexed: 01/17/2023]
Abstract
Chk1 is a key regulator of DNA damage checkpoint responses and genome stability in eukaryotes. To better understand how checkpoint proficiency relates to cancer development, we investigated the effects of genetic ablation of Chk1 in the mouse skin on tumors induced by chemical carcinogens. We found that homozygous deletion of Chk1 immediately before carcinogen exposure strongly suppressed benign tumor (papilloma) formation, and that the few, small lesions that formed in the ablated skin always retained Chk1 expression. Remarkably, Chk1 deletion rapidly triggered spontaneous cell proliferation, γ-H2AX staining and apoptosis within the hair follicle, a principal site of origin for carcinogen-induced tumors. At later times, the ablated skin was progressively repopulated by non-recombined Chk1-expressing cells and ultimately normal sensitivity to tumor induction was restored when carcinogen treatment was delayed. In marked contrast, papillomas formed normally in Chk1 hemizygous skin but showed an increased propensity to progress to carcinoma. Thus, complete loss of Chk1 is incompatible with epithelial tumorigenesis, whereas partial loss of function (haploinsufficiency) fosters benign malignant tumor progression.
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Affiliation(s)
- L M Tho
- Beatson Institute for Cancer Research, Bearsden, Glasgow, UK
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Conditional activation of Pik3ca(H1047R) in a knock-in mouse model promotes mammary tumorigenesis and emergence of mutations. Oncogene 2012; 32:318-26. [PMID: 22370636 PMCID: PMC3550595 DOI: 10.1038/onc.2012.53] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Oncogenic mutations in PIK3CA, which encodes the phosphoinositide-3-kinase (PI3K) catalytic subunit p110α, occur in ∼25% of human breast cancers. In this study, we report the development of a knock-in mouse model for breast cancer where the endogenous Pik3ca allele was modified to allow tissue-specific conditional expression of a frequently found Pik3caH1047R (Pik3cae20H1047R) mutant allele. We found that activation of the latent Pik3caH1047R allele resulted in breast tumors with multiple histological types. Whole-exome analysis of the Pik3caH1047R-driven mammary tumors identified multiple mutations, including Trp53 mutations that appeared spontaneously during the development of adenocarinoma and spindle cell tumors. Further, we used this model to test the efficacy of GDC-0941, a PI3K inhibitor, in clinical development, and showed that the tumors respond to PI3K inhibition.
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Checkpoint kinase 1 (Chk1)-short is a splice variant and endogenous inhibitor of Chk1 that regulates cell cycle and DNA damage checkpoints. Proc Natl Acad Sci U S A 2011; 109:197-202. [PMID: 22184239 DOI: 10.1073/pnas.1104767109] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Checkpoint kinase 1 (Chk1) is a key regulator of checkpoint signaling in both the unperturbed cell cycle and DNA damage response. Under these conditions, Chk1 becomes active to prevent premature CDK1 activation and mitotic entry until DNA is properly replicated or repaired. It is unclear how Chk1 activity is controlled in the unperturbed cell cycle. During DNA damage, Chk1 is activated by ataxia telangiectasia and Rad3 related (ATR)-mediated phosphorylation; however, it is not entirely clear how this phosphorylation results in Chk1 activation. Here we report an N-terminally truncated alternative splice variant of Chk1, Chk1-S. Importantly, we show that Chk1-S is an endogenous repressor and regulator of Chk1. In the unperturbed cell cycle, Chk1-S interacts with and antagonizes Chk1 to promote the S-to-G2/M phase transition. During DNA damage, Chk1 is phosphorylated, which disrupts the Chk1-Chk1-S interaction, resulting in free, active Chk1 to arrest the cell cycle and facilitate DNA repair. Higher levels of Chk1-S are expressed, along with Chk1, in fetal and cancer tissues than in normal tissues. However, forced overexpression of Chk1-S in cultured cells and tumor xenografts induces premature mitotic entry, mitotic catastrophe, and reduction of tumor growth. The identification of Chk1-S as a unique splice variant and key regulator of Chk1 provides insights into cell cycle regulation and DNA damage response.
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Sørensen CS, Syljuåsen RG. Safeguarding genome integrity: the checkpoint kinases ATR, CHK1 and WEE1 restrain CDK activity during normal DNA replication. Nucleic Acids Res 2011; 40:477-86. [PMID: 21937510 PMCID: PMC3258124 DOI: 10.1093/nar/gkr697] [Citation(s) in RCA: 225] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Mechanisms that preserve genome integrity are highly important during the normal life cycle of human cells. Loss of genome protective mechanisms can lead to the development of diseases such as cancer. Checkpoint kinases function in the cellular surveillance pathways that help cells to cope with DNA damage. Importantly, the checkpoint kinases ATR, CHK1 and WEE1 are not only activated in response to exogenous DNA damaging agents, but are active during normal S phase progression. Here, we review recent evidence that these checkpoint kinases are critical to avoid deleterious DNA breakage during DNA replication in normal, unperturbed cell cycle. Possible mechanisms how loss of these checkpoint kinases may cause DNA damage in S phase are discussed. We propose that the majority of DNA damage is induced as a consequence of deregulated CDK activity that forces unscheduled initiation of DNA replication. This could generate structures that are cleaved by DNA endonucleases leading to the formation of DNA double-strand breaks. Finally, we discuss how these S phase effects may impact on our understanding of cancer development following disruption of these checkpoint kinases, as well as on the potential of these kinases as targets for cancer treatment.
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Affiliation(s)
- Claus Storgaard Sørensen
- Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark.
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38
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Höglund A, Nilsson LM, Muralidharan SV, Hasvold LA, Merta P, Rudelius M, Nikolova V, Keller U, Nilsson JA. Therapeutic implications for the induced levels of Chk1 in Myc-expressing cancer cells. Clin Cancer Res 2011; 17:7067-79. [PMID: 21933891 DOI: 10.1158/1078-0432.ccr-11-1198] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The transcription factor c-Myc (or "Myc") is a master regulator of pathways driving cell growth and proliferation. MYC is deregulated in many human cancers, making its downstream target genes attractive candidates for drug development. We report the unexpected finding that B-cell lymphomas from mice and patients exhibit a striking correlation between high levels of Myc and checkpoint kinase 1 (Chk1). EXPERIMENTAL DESIGN By in vitro cell biology studies as well as preclinical studies using a genetically engineered mouse model, we evaluated the role of Chk1 in Myc-overexpressing cells. RESULTS We show that Myc indirectly induces Chek1 transcript and protein expression, independently of DNA damage response proteins such as ATM and p53. Importantly, we show that inhibition of Chk1, by either RNA interference or a novel highly selective small molecule inhibitor, results in caspase-dependent apoptosis that affects Myc-overexpressing cells in both in vitro and in vivo mouse models of B-cell lymphoma. CONCLUSION Our data suggest that Chk1 inhibitors should be further evaluated as potential drugs against Myc-driven malignancies such as certain B-cell lymphoma/leukemia, neuroblastoma, and some breast and lung cancers.
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Affiliation(s)
- Andreas Höglund
- Department of Molecular Biology, Umeå University, Umeå, Sweden
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Tp53 deletion in B lineage cells predisposes mice to lymphomas with oncogenic translocations. Oncogene 2011; 30:4757-64. [PMID: 21625223 DOI: 10.1038/onc.2011.191] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Inactivating Tp53 mutations are frequent genetic lesions in human tumors that harbor genomic instability, including B lineage lymphomas with IG translocations. Antigen receptor genes are assembled and modified in developing lymphocytes by RAG/AID-initiated genomic rearrangements that involve the induction of DNA double strand breaks (DSBs). Although TP53 inhibits the persistence of DSBs and induces apoptosis to protect cells from genomic instability and transformation, the development of spontaneous tumors harboring clonal translocations has not been reported in mice that only lack wild-type Tp53 protein or express Tp53 mutants. Tp53-deficient (Tp53(-/-)) mice succumb to T lineage lymphomas lacking clonal translocations but develop B lymphoid tumors containing immunoglobulin (Ig) translocations upon combined inactivation of DSB repair factors, RAG mutation or AID overexpression; mice expressing apoptosis-defective Tp53 mutants develop B cell lymphomas that have not been characterized for potential genomic instability. As somatic rather than germline inactivating mutations of TP53 are typically associated with human cancers and Tp53 deletion has cellular context dependent effects upon lymphocyte transformation, we generated mice with conditional Tp53 deletion in lineage-committed B lymphocytes to avoid complications associated with defective Tp53 responses during embryogenesis and/or in multi-lineage potential cells and, thereby, directly evaluate the potential physiological role of Tp53 in suppressing translocations in differentiated cells. These mb1-cre:Tp53(flox/flox) mice succumbed to lymphoid tumors containing Ig gene rearrangements and immunophenotypes characteristic of B cells from various developmental stages. Most mb1-cre:Tp53(flox/flox) tumors harbored clonal translocations, including Igh/c-myc or other oncogenic translocations generated by the aberrant repair of RAG/AID-generated DSBs. Our data indicate that Tp53 serves critical functions in B lineage lymphocytes to prevent transformation caused by translocations in cell populations experiencing physiological levels of RAG/AID-initiated DSB intermediates, and provide evidence that the somatic TP53 mutations found in diffuse large B-cell lymphoma and Burkitt's lymphoma may contribute to the development of these human malignancies.
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Death by releasing the breaks: CHK1 inhibitors as cancer therapeutics. Trends Mol Med 2010; 17:88-96. [PMID: 21087899 DOI: 10.1016/j.molmed.2010.10.009] [Citation(s) in RCA: 209] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 10/22/2010] [Accepted: 10/25/2010] [Indexed: 11/23/2022]
Abstract
Defects in p53 function, which occur frequently in human cancers due to mutations in TP53 or disruptions in the p53 regulatory pathway, render cells dependent on CHK1 (Checkpoint Kinase 1) to activate cell cycle checkpoints. In the presence of DNA damage or replication stress, inhibition of CHK1 leads to "mitotic catastrophe" and cell death in p53-deficient tumors while sparing p53-proficient cells. CHK1 inhibitors sensitize tumors to a variety of DNA-damaging agents or antimetabolites in preclinical models and are being evaluated in early phase clinical trials. In this review, we summarize recent advances and controversies in the development and application of CHK1 inhibitors as cancer therapeutics.
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Vitale I, Galluzzi L, Senovilla L, Criollo A, Jemaà M, Castedo M, Kroemer G. Illicit survival of cancer cells during polyploidization and depolyploidization. Cell Death Differ 2010; 18:1403-13. [PMID: 21072053 DOI: 10.1038/cdd.2010.145] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Tetraploidy and the depolyploidization of tetraploid cells may contribute to oncogenesis. Several mechanisms have evolved to avoid the generation, survival, proliferation and depolyploidization of tetraploids. Cells that illicitly survive these checkpoints are prone to chromosomal instability and aneuploidization. Along with their replication, tetraploids constantly undergo chromosomal rearrangements that eventually lead to pseudodiploidy by two non-exclusive mechanisms: (i) multipolar divisions and (ii) illicit bipolar divisions in the presence of improper microtubule-kinetochore attachments. Here, we describe the regulation and the molecular mechanisms that underlie such a 'polyploidization-depolyploidization' cascade, while focusing on the role of oncogenes and tumor suppressor genes in tetraploidy-driven tumorigenesis. We speculate that the identification of signaling/metabolic cascades that are required for the survival of tetraploid or aneuploid (but not diploid) cancer cells may pave the way for the development of novel broad-spectrum anticancer agents.
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