101
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TACC3 deregulates the DNA damage response and confers sensitivity to radiation and PARP inhibition. Oncogene 2014; 34:1667-78. [PMID: 24769898 DOI: 10.1038/onc.2014.105] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 02/28/2014] [Accepted: 03/12/2014] [Indexed: 12/21/2022]
Abstract
Deregulation of the transforming acidic coiled-coil protein 3 (TACC3), an important factor in the centrosome-microtubule system, has been linked to a variety of human cancer types. We have recently reported on the oncogenic potential of TACC3; however, the molecular mechanisms by which TACC3 mediates oncogenic function remain to be elucidated. In this study, we show that high levels of TACC3 lead to the accumulation of DNA double-strand breaks (DSBs) and disrupt the normal cellular response to DNA damage, at least in part, by negatively regulating the expression of ataxia telangiectasia mutated (ATM) and the subsequent DNA damage response (DDR) signaling cascade. Cells expressing high levels of TACC3 display defective checkpoints and DSB-mediated homologous recombination (HR) and non-homologous end joining (NHEJ) repair systems, leading to genomic instability. Importantly, high levels of TACC3 confer cellular sensitization to radiation and poly(ADP-ribose) polymerase (PARP) inhibition. Overall, our findings provide critical information regarding the mechanisms by which TACC3 contributes to genomic instability, potentially leading to cancer development, and suggest a novel prognostic, diagnostic and therapeutic strategy for the treatment of cancer types expressing high levels of TACC3.
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102
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Sadri N, Surrey LF, Fraker DL, Zhang PJ. Retroperitoneal dedifferentiated liposarcoma lacking MDM2 amplification in a patient with a germ line CHEK2 mutation. Virchows Arch 2014; 464:505-9. [DOI: 10.1007/s00428-014-1563-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/16/2013] [Accepted: 02/17/2014] [Indexed: 10/25/2022]
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103
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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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104
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Dai XX, Duan X, Liu HL, Cui XS, Kim NH, Sun SC. Chk2 regulates cell cycle progression during mouse oocyte maturation and early embryo development. Mol Cells 2014; 37:126-32. [PMID: 24598997 PMCID: PMC3935625 DOI: 10.14348/molcells.2014.2259] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/13/2013] [Accepted: 12/13/2013] [Indexed: 12/21/2022] Open
Abstract
As a tumor suppressor homologue during mitosis, Chk2 is involved in replication checkpoints, DNA repair, and cell cycle arrest, although its functions during mouse oocyte meiosis and early embryo development remain uncertain. We investigated the functions of Chk2 during mouse oocyte maturation and early embryo development. Chk2 exhibited a dynamic localization pattern; Chk2 expression was restricted to germinal vesicles at the germinal vesicle (GV) stage, was associated with centromeres at pro-metaphase I (Pro-MI), and localized to spindle poles at metaphase I (MI). Disrupting Chk2 activity resulted in cell cycle progression defects. First, inhibitor-treated oocytes were arrested at the GV stage and failed to undergo germinal vesicle breakdown (GVBD); this could be rescued after Chk2 inhibition release. Second, Chk2 inhibition after oocyte GVBD caused MI arrest. Third, the first cleavage of early embryo development was disrupted by Chk2 inhibition. Additionally, in inhibitor-treated oocytes, checkpoint protein Bub3 expression was consistently localized at centromeres at the MI stage, which indicated that the spindle assembly checkpoint (SAC) was activated. Moreover, disrupting Chk2 activity in oocytes caused severe chromosome misalignments and spindle disruption. In inhibitor-treated oocytes, centrosome protein γ-tubulin and Polo-like kinase 1 (Plk1) were dissociated from spindle poles. These results indicated that Chk2 regulated cell cycle progression and spindle assembly during mouse oocyte maturation and early embryo development.
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Affiliation(s)
- Xiao-Xin Dai
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095,
China
| | - Xing Duan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095,
China
| | - Hong-Lin Liu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095,
China
| | | | | | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095,
China
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105
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The Molecular Crosstalk between the MET Receptor Tyrosine Kinase and the DNA Damage Response-Biological and Clinical Aspects. Cancers (Basel) 2013; 6:1-27. [PMID: 24378750 PMCID: PMC3980615 DOI: 10.3390/cancers6010001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 12/06/2013] [Accepted: 12/06/2013] [Indexed: 02/07/2023] Open
Abstract
Radiation therapy remains an imperative treatment modality for numerous malignancies. Enduring significant technical achievements both on the levels of treatment planning and radiation delivery have led to improvements in local control of tumor growth and reduction in healthy tissue toxicity. Nevertheless, resistance mechanisms, which presumably also involve activation of DNA damage response signaling pathways that eventually may account for loco-regional relapse and consequent tumor progression, still remain a critical problem. Accumulating data suggest that signaling via growth factor receptor tyrosine kinases, which are aberrantly expressed in many tumors, may interfere with the cytotoxic impact of ionizing radiation via the direct activation of the DNA damage response, leading eventually to so-called tumor radioresistance. The aim of this review is to overview the current known data that support a molecular crosstalk between the hepatocyte growth factor receptor tyrosine kinase MET and the DNA damage response. Apart of extending well established concepts over MET biology beyond its function as a growth factor receptor, these observations directly relate to the role of its aberrant activity in resistance to DNA damaging agents, such as ionizing radiation, which are routinely used in cancer therapy and advocate tumor sensitization towards DNA damaging agents in combination with MET targeting.
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106
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The ATM-mediated DNA-damage response. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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107
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Pitts TM, Davis SL, Eckhardt SG, Bradshaw-Pierce EL. Targeting nuclear kinases in cancer: development of cell cycle kinase inhibitors. Pharmacol Ther 2013; 142:258-69. [PMID: 24362082 DOI: 10.1016/j.pharmthera.2013.12.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 11/27/2013] [Indexed: 12/13/2022]
Abstract
Cellular proliferation is a tightly controlled set of events that is regulated by numerous nuclear protein kinases. The proteins involved include checkpoint kinases (CHK), cyclin-dependent kinases (CDK), which regulate the cell cycle and aurora kinases (AURK) and polo-like kinases (PLK), which regulate mitosis. In cancer, these nuclear kinases are often dysregulated and cause uncontrolled cell proliferation and growth. Much work has gone into developing novel therapeutics that target each of these protein kinases in cancer but none have been approved in patients. In this review we provide an overview of the current compounds being developed clinically to target these nuclear kinases involved in regulating the cell cycle and mitosis.
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Affiliation(s)
- Todd M Pitts
- Division of Medical Oncology, University of Colorado Denver, Anschutz Medical Campus, United States; University of Colorado Cancer Center, University of Colorado Denver, Anschutz Medical Campus, United States.
| | - S Lindsey Davis
- Division of Medical Oncology, University of Colorado Denver, Anschutz Medical Campus, United States
| | - S Gail Eckhardt
- Division of Medical Oncology, University of Colorado Denver, Anschutz Medical Campus, United States; University of Colorado Cancer Center, University of Colorado Denver, Anschutz Medical Campus, United States
| | - Erica L Bradshaw-Pierce
- Department of Pharmaceutical Sciences, University of Colorado Denver, Anschutz Medical Campus, United States; University of Colorado Cancer Center, University of Colorado Denver, Anschutz Medical Campus, United States
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108
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Booth L, Roberts JL, Cruickshanks N, Conley A, Durrant DE, Das A, Fisher PB, Kukreja RC, Grant S, Poklepovic A, Dent P. Phosphodiesterase 5 inhibitors enhance chemotherapy killing in gastrointestinal/genitourinary cancer cells. Mol Pharmacol 2013; 85:408-19. [PMID: 24353313 DOI: 10.1124/mol.113.090043] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The present studies determined whether clinically relevant phosphodiesterase 5 (PDE5) inhibitors interacted with clinically relevant chemotherapies to kill gastrointestinal/genitourinary cancer cells. In bladder cancer cells, regardless of H-RAS mutational status, at clinically achievable doses, PDE5 inhibitors interacted in a greater than additive fashion with doxorubicin/mitomycin C/gemcitabine/cisplatin/paclitaxel to cause cell death. In pancreatic tumor cells expressing mutant active K-RAS, PDE5 inhibitors interacted in a greater than additive fashion with doxorubicin/gemcitabine/paclitaxel to cause cell death. The most potent PDE5 inhibitor was sildenafil. Knock down of PDE5 expression recapitulated the combination effects of PDE5 inhibitor drugs with chemotherapy drugs. Expression of cellular FLICE-like inhibitory protein-short did not significantly inhibit chemotherapy lethality but did significantly reduce enhanced killing in combination with sildenafil. Overexpression of B-cell lymphoma-extra large suppressed individual and combination drug toxicities. Knock down of CD95 or Fas-associated death domain protein suppressed drug combination toxicity. Combination toxicity was also abolished by necrostatin or receptor interacting protein 1 knock down. Treatment with PDE5 inhibitors and chemotherapy drugs promoted autophagy, which was maximal at ∼24 hour posttreatment, and 3-methyl adenine or knock down of Beclin1 suppressed drug combination lethality by ∼50%. PDE5 inhibitors enhanced and prolonged the induction of DNA damage as judged by Comet assays and γhistone 2AX (γH2AX) and checkpoint kinase 2 (CHK2) phosphorylation. Knock down of ataxia telangiectasia mutated suppressed γH2AX and CHK2 phosphorylation and enhanced drug combination lethality. Collectively our data demonstrate that the combination of PDE5 inhibitors with standard of care chemotherapy agents for gastrointestinal/genitourinary cancers represents a novel modality.
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Affiliation(s)
- Laurence Booth
- Departments of Biochemistry and Molecular Biology (L.B., J.L.R., N.C., A.C., P.D.), Cardiology (D.E.D., A.D., R.C.K.), Medicine (S.G., A.P.), Human and Molecular Genetics (P.B.F.), Virginia Commonwealth University, Richmond, Virginia
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109
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Chen ESW, Hoch NC, Wang SC, Pellicioli A, Heierhorst J, Tsai MD. Use of quantitative mass spectrometric analysis to elucidate the mechanisms of phospho-priming and auto-activation of the checkpoint kinase Rad53 in vivo. Mol Cell Proteomics 2013; 13:551-65. [PMID: 24302356 PMCID: PMC3916653 DOI: 10.1074/mcp.m113.034058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The cell cycle checkpoint kinases play central roles in the genome maintenance of eukaryotes. Activation of the yeast checkpoint kinase Rad53 involves Rad9 or Mrc1 adaptor-mediated phospho-priming by Mec1 kinase, followed by auto-activating phosphorylation within its activation loop. However, the mechanisms by which these adaptors regulate priming phosphorylation of specific sites and how this then leads to Rad53 activation remain poorly understood. Here we used quantitative mass spectrometry to delineate the stepwise phosphorylation events in the activation of endogenous Rad53 in response to S phase alkylation DNA damage, and we show that the two Rad9 and Mrc1 adaptors, the four N-terminal Mec1-target TQ sites of Rad53 (Rad53-SCD1), and Rad53-FHA2 coordinate intimately for optimal priming phosphorylation to support substantial Rad53 auto-activation. Rad9 or Mrc1 alone can mediate surprisingly similar Mec1 target site phosphorylation patterns of Rad53, including previously undetected tri- and tetraphosphorylation of Rad53-SCD1. Reducing the number of TQ motifs turns the SCD1 into a proportionally poorer Mec1 target, which then requires the presence of both Mrc1 and Rad9 for sufficient priming and auto-activation. The phosphothreonine-interacting Rad53-FHA domains, particularly FHA2, regulate phospho-priming by interacting with the checkpoint mediators but do not seem to play a major role in the phospho-SCD1-dependent auto-activation step. Finally, mutation of all four SCD1 TQ motifs greatly reduces Rad53 activation but does not eliminate it, and residual Rad53 activity in this mutant is dependent on Rad9 but not Mrc1. Altogether, our results provide a paradigm for how phosphorylation site clusters and checkpoint mediators can be involved in the regulation of signaling relay in protein kinase cascades in vivo and elucidate an SCD1-independent Rad53 auto-activation mechanism through the Rad9 pathway. The work also demonstrates the power of mass spectrometry for in-depth analyses of molecular mechanisms in cellular signaling in vivo.
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Affiliation(s)
- Eric S-W Chen
- Institute of Biological Chemistry, Taipei 115, Taiwan
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110
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Gutiérrez-González A, Belda-Iniesta C, Bargiela-Iparraguirre J, Dominguez G, García Alfonso P, Perona R, Sanchez-Perez I. Targeting Chk2 improves gastric cancer chemotherapy by impairing DNA damage repair. Apoptosis 2013; 18:347-60. [PMID: 23271172 DOI: 10.1007/s10495-012-0794-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Our results demonstrate that the addition of cisplatin after paclitaxel-induced mitotic arrest was more effective than individual treatment on gastric adenocarcinoma cells (MKN45). However, the treatment did not induce benefits in cells derived from lymph node metastasis (ST2957). Time-lapse microscopy revealed that cell death was caused by mitotic catastrophe and apoptosis induction, as the use of the caspase inhibitor z-VAD-fmk decreased cell death. We propose that the molecular mechanism mediating this cell fate is a slippage suffered by these cells, given that our Western blot (WB) analysis revealed premature cyclin B degradation. This resulted in the cell exiting from mitosis without undergoing DNA damage repair, as demonstrated by the strong phosphorylation of H2AX. A comet assay indicated that DNA repair was impaired, and Western blotting showed that the Chk2 protein was degraded after sequential treatment (paclitaxel-cisplatin). Based on these results, the modulation of cell death during mitosis may be an effective strategy for gastric cancer therapy.
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111
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Murphy SJ, Hart SN, Lima JF, Kipp BR, Klebig M, Winters JL, Szabo C, Zhang L, Eckloff BW, Petersen GM, Scherer SE, Gibbs RA, McWilliams RR, Vasmatzis G, Couch FJ. Genetic alterations associated with progression from pancreatic intraepithelial neoplasia to invasive pancreatic tumor. Gastroenterology 2013; 145:1098-1109.e1. [PMID: 23912084 PMCID: PMC3926442 DOI: 10.1053/j.gastro.2013.07.049] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 07/12/2013] [Accepted: 07/29/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Increasing grade of pancreatic intraepithelial neoplasia (PanIN) has been associated with progression to pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms that control progression from PanINs to PDAC are not well understood. We investigated the genetic alterations involved in this process. METHODS Genomic DNA samples from laser-capture microdissected PDACs and adjacent PanIN2 and PanIN3 lesions from 10 patients with pancreatic cancer were analyzed by exome sequencing. RESULTS Similar numbers of somatic mutations were identified in PanINs and tumors, but the mutational load varied greatly among cases. Ten of the 15 isolated PanINs shared more than 50% of somatic mutations with associated tumors. Mutations common to tumors and clonally related PanIN2 and PanIN3 lesions were identified as genes that could promote carcinogenesis. KRAS and TP53 frequently were altered in PanINs and tumors, but few other recurrently modified genes were detected. Mutations in DNA damage response genes were prevalent in all samples. Genes that encode proteins involved in gap junctions, the actin cytoskeleton, the mitogen-activated protein kinase signaling pathway, axon guidance, and cell-cycle regulation were among the earliest targets of mutagenesis in PanINs that progressed to PDAC. CONCLUSIONS Early stage PanIN2 lesions appear to contain many of the somatic gene alterations required for PDAC development.
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Affiliation(s)
- Stephen J Murphy
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota
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112
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Wierstra I. The transcription factor FOXM1 (Forkhead box M1): proliferation-specific expression, transcription factor function, target genes, mouse models, and normal biological roles. Adv Cancer Res 2013; 118:97-398. [PMID: 23768511 DOI: 10.1016/b978-0-12-407173-5.00004-2] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor, which stimulates cell proliferation and exhibits a proliferation-specific expression pattern. Accordingly, both the expression and the transcriptional activity of FOXM1 are increased by proliferation signals, but decreased by antiproliferation signals, including the positive and negative regulation by protooncoproteins or tumor suppressors, respectively. FOXM1 stimulates cell cycle progression by promoting the entry into S-phase and M-phase. Moreover, FOXM1 is required for proper execution of mitosis. Accordingly, FOXM1 regulates the expression of genes, whose products control G1/S-transition, S-phase progression, G2/M-transition, and M-phase progression. Additionally, FOXM1 target genes encode proteins with functions in the execution of DNA replication and mitosis. FOXM1 is a transcriptional activator with a forkhead domain as DNA binding domain and with a very strong acidic transactivation domain. However, wild-type FOXM1 is (almost) inactive because the transactivation domain is repressed by three inhibitory domains. Inactive FOXM1 can be converted into a very potent transactivator by activating signals, which release the transactivation domain from its inhibition by the inhibitory domains. FOXM1 is essential for embryonic development and the foxm1 knockout is embryonically lethal. In adults, FOXM1 is important for tissue repair after injury. FOXM1 prevents premature senescence and interferes with contact inhibition. FOXM1 plays a role for maintenance of stem cell pluripotency and for self-renewal capacity of stem cells. The functions of FOXM1 in prevention of polyploidy and aneuploidy and in homologous recombination repair of DNA-double-strand breaks suggest an importance of FOXM1 for the maintenance of genomic stability and chromosomal integrity.
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113
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Poulton JS, Mu FW, Roberts DM, Peifer M. APC2 and Axin promote mitotic fidelity by facilitating centrosome separation and cytoskeletal regulation. Development 2013; 140:4226-36. [PMID: 24026117 DOI: 10.1242/dev.094425] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To ensure the accurate transmission of genetic material, chromosome segregation must occur with extremely high fidelity. Segregation errors lead to chromosomal instability (CIN), with deleterious consequences. Mutations in the tumor suppressor adenomatous polyposis coli (APC) initiate most colon cancers and have also been suggested to promote disease progression through increased CIN, but the mechanistic role of APC in preventing CIN remains controversial. Using fly embryos as a model, we investigated the role of APC proteins in CIN. Our findings suggest that APC2 loss leads to increased rates of chromosome segregation error. This occurs through a cascade of events beginning with incomplete centrosome separation leading to failure to inhibit formation of ectopic cleavage furrows, which result in mitotic defects and DNA damage. We test several hypotheses related to the mechanism of action of APC2, revealing that APC2 functions at the embryonic cortex with several protein partners, including Axin, to promote mitotic fidelity. Our in vivo data demonstrate that APC2 protects genome stability by modulating mitotic fidelity through regulation of the cytoskeleton.
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Affiliation(s)
- John S Poulton
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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114
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Sermeus A, Rebucci M, Fransolet M, Flamant L, Desmet D, Delaive E, Arnould T, Michiels C. Differential effect of hypoxia on etoposide-induced DNA damage response and p53 regulation in different cell types. J Cell Physiol 2013; 228:2365-76. [DOI: 10.1002/jcp.24409] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 05/10/2013] [Indexed: 12/22/2022]
Affiliation(s)
- Audrey Sermeus
- Laboratory of Biochemistry and Cellular Biology (URBC); NARILIS, University of Namur; Namur Belgium
| | - Magali Rebucci
- Laboratory of Biochemistry and Cellular Biology (URBC); NARILIS, University of Namur; Namur Belgium
| | - Maude Fransolet
- Laboratory of Biochemistry and Cellular Biology (URBC); NARILIS, University of Namur; Namur Belgium
| | - Lionel Flamant
- Laboratory of Biochemistry and Cellular Biology (URBC); NARILIS, University of Namur; Namur Belgium
| | - Déborah Desmet
- Laboratory of Biochemistry and Cellular Biology (URBC); NARILIS, University of Namur; Namur Belgium
| | - Edouard Delaive
- Laboratory of Biochemistry and Cellular Biology (URBC); NARILIS, University of Namur; Namur Belgium
| | - Thierry Arnould
- Laboratory of Biochemistry and Cellular Biology (URBC); NARILIS, University of Namur; Namur Belgium
| | - Carine Michiels
- Laboratory of Biochemistry and Cellular Biology (URBC); NARILIS, University of Namur; Namur Belgium
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115
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de Miranda NFCC, Peng R, Georgiou K, Wu C, Falk Sörqvist E, Berglund M, Chen L, Gao Z, Lagerstedt K, Lisboa S, Roos F, van Wezel T, Teixeira MR, Rosenquist R, Sundström C, Enblad G, Nilsson M, Zeng Y, Kipling D, Pan-Hammarström Q. DNA repair genes are selectively mutated in diffuse large B cell lymphomas. ACTA ACUST UNITED AC 2013; 210:1729-42. [PMID: 23960188 PMCID: PMC3754869 DOI: 10.1084/jem.20122842] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
DNA repair mechanisms are fundamental for B cell development, which relies on the somatic diversification of the immunoglobulin genes by V(D)J recombination, somatic hypermutation, and class switch recombination. Their failure is postulated to promote genomic instability and malignant transformation in B cells. By performing targeted sequencing of 73 key DNA repair genes in 29 B cell lymphoma samples, somatic and germline mutations were identified in various DNA repair pathways, mainly in diffuse large B cell lymphomas (DLBCLs). Mutations in mismatch repair genes (EXO1, MSH2, and MSH6) were associated with microsatellite instability, increased number of somatic insertions/deletions, and altered mutation signatures in tumors. Somatic mutations in nonhomologous end-joining (NHEJ) genes (DCLRE1C/ARTEMIS, PRKDC/DNA-PKcs, XRCC5/KU80, and XRCC6/KU70) were identified in four DLBCL tumors and cytogenetic analyses revealed that translocations involving the immunoglobulin-heavy chain locus occurred exclusively in NHEJ-mutated samples. The novel mutation targets, CHEK2 and PARP1, were further screened in expanded DLBCL cohorts, and somatic as well as novel and rare germline mutations were identified in 8 and 5% of analyzed tumors, respectively. By correlating defects in a subset of DNA damage response and repair genes with genomic instability events in tumors, we propose that these genes play a role in DLBCL lymphomagenesis.
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Affiliation(s)
- Noel F C C de Miranda
- Clinical Immunology, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital, Huddinge, Sweden
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116
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Halaby MJ, Hakem R, Hakem A. Pirh2: an E3 ligase with central roles in the regulation of cell cycle, DNA damage response, and differentiation. Cell Cycle 2013; 12:2733-7. [PMID: 23966173 DOI: 10.4161/cc.25785] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ubiquitylation is currently recognized as a major posttranslational modification that regulates diverse cellular processes. Pirh2 is a ubiquitin E3 ligase that regulates the turnover and functionality of several proteins involved in cell proliferation and differentiation, cell cycle checkpoints, and cell death. Here we review the role of Pirh2 as a regulator of the DNA damage response through the ubiquitylation of p53, Chk2, p73, and PolH. By ubiquitylating these proteins, Pirh2 regulates cell cycle checkpoints and cell death in response to DNA double-strand breaks or the formation of bulky DNA lesions. We also discuss how Pirh2 affects cell proliferation and differentiation in unstressed conditions through ubiquitylation and degradation of c-Myc, p63, and p27(kip1). Finally, we link these different functions of Pirh2 to its role as a tumor suppressor in mice and as a prognosis marker in various human cancer subtypes.
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Affiliation(s)
- Marie-jo Halaby
- Ontario Cancer Institute; University Health Network and Department of Medical Biophysics; University of Toronto; Toronto, Ontario, Canada
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117
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Ogiwara H, Ui A, Shiotani B, Zou L, Yasui A, Kohno T. Curcumin suppresses multiple DNA damage response pathways and has potency as a sensitizer to PARP inhibitor. Carcinogenesis 2013; 34:2486-97. [PMID: 23825154 DOI: 10.1093/carcin/bgt240] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Inhibitors of poly(ADP-ribose) polymerase (PARP) are promising anticancer drugs, particularly for the treatment of tumors deficient in the DNA damage response (DDR). However, it is challenging to design effective therapeutic strategies for use of these compounds against cancers without DDR deficiencies. In this context, combination therapies in which PARP inhibitors are used alongside DDR inhibitors have elicited a great deal of interest. Curcumin, a component of turmeric (Curcuma longa), has been tested in clinical studies for its chemosensitizing potential; however, the mechanisms of chemosensitization by curcumin have not been fully elucidated. This study demonstrates that curcumin suppresses three major DDR pathways: non-homologous end joining (NHEJ), homologous recombination (HR) and the DNA damage checkpoint. Curcumin suppresses the histone acetylation at DNA double-strand break (DSB) sites by inhibiting histone acetyltransferase activity, thereby reducing recruitment of the key NHEJ factor KU70/KU80 to DSB sites. Curcumin also suppresses HR by reducing expression of the BRCA1 gene, which regulates HR, by impairing histone acetylation at the BRCA1 promoter. Curcumin also inhibits ataxia telangiectasia and Rad3-related protein (ATR) kinase (IC50 in vitro = 493 nM), resulting in impaired activation of ATR-CHK1 signaling, which is necessary for HR and the DNA damage checkpoint pathway. Thus, curcumin suppresses three DDR pathways by inhibiting histone acetyltransferases and ATR. Concordantly, curcumin sensitizes cancer cells to PARP inhibitors by enhancing apoptosis and mitotic catastrophe via inhibition of both the DNA damage checkpoint and DSB repair. Our results indicate that curcumin is a promising sensitizer for PARP inhibitor-based therapy.
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Affiliation(s)
- Hideaki Ogiwara
- Division of Genome Biology, National Cancer Center Research Institute, Tokyo 104-0045, Japan
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118
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Ou DL, Lee BS, Chang YC, Lin LI, Liou JY, Hsu C, Cheng AL. Potentiating the efficacy of molecular targeted therapy for hepatocellular carcinoma by inhibiting the insulin-like growth factor pathway. PLoS One 2013; 8:e66589. [PMID: 23818948 PMCID: PMC3688529 DOI: 10.1371/journal.pone.0066589] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 05/08/2013] [Indexed: 01/20/2023] Open
Abstract
Insulin-like growth factor (IGF) signaling pathway is an important regulatory mechanism of tumorigenesis and drug resistance in many cancers. The present study explored the potential synergistic effects between IGF receptor (IGFR) inhibition and other molecular targeted agents (MTA) in HCC cells. HCC cell lines (Hep3B, PLC5, and SK-Hep1) and HUVECs were tested. The MTA tested included sorafenib, sunitinib, and the IGFR kinase inhibitor NVP-AEW541. The potential synergistic antitumor effects were tested by median dose effect analysis and apoptosis assay in vitro and by xenograft models in vivo. The activity and functional significance of pertinent signaling pathways and expression of apoptosis-related proteins were measured by RNA interference and Western blotting. We found that IGF can activate IGFR and downstream AKT signaling activities in all the HCC cells tested, but the growth-stimulating effect of IGF was most prominent in Hep3B cells. NVP-AEW541 can abrogate IGF-induced activation of IGFR and AKT signaling in HCC cells. IGF can increase the resistance of HCC cells to sunitinib. The apoptosis-inducing effects of sunitinib, but not sorafenib, were enhanced when IGFR signaling activity was inhibited by NVP-AEW541 or IGFR knockdown. Chk2 kinase activation was found contributory to the synergistic anti-tumor effects between sunitinib and IGFR inhibition. Our data indicate that the apoptosis-potentiating effects of IGFR inhibition for HCC may be drug-specific. Combination therapy of IGFR inhibitors with other MTA may improve the therapeutic efficacy in HCC.
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MESH Headings
- Animals
- Antineoplastic Agents/pharmacology
- Blotting, Western
- Carcinoma, Hepatocellular/drug therapy
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/pathology
- Cell Line, Tumor
- Cell Survival/drug effects
- Cells, Cultured
- Checkpoint Kinase 2/metabolism
- Drug Resistance, Neoplasm/drug effects
- Drug Synergism
- Humans
- Indoles/pharmacology
- Liver Neoplasms/drug therapy
- Liver Neoplasms/metabolism
- Liver Neoplasms/pathology
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Nude
- Niacinamide/analogs & derivatives
- Niacinamide/pharmacology
- Phenylurea Compounds/pharmacology
- Phosphorylation/drug effects
- Protein Kinase Inhibitors/pharmacology
- Pyrimidines/pharmacology
- Pyrroles/pharmacology
- RNA Interference
- Receptor, IGF Type 1/antagonists & inhibitors
- Receptor, IGF Type 1/genetics
- Receptor, IGF Type 1/metabolism
- Signal Transduction/drug effects
- Sorafenib
- Sunitinib
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Da-Liang Ou
- Graduate Institute of Oncology, College of Medicine, National Taiwan University, Taipei, Taiwan
- National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Bin-Shyun Lee
- National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan
- Department of Oncology, National Taiwan University Hospital, Taipei, Taiwan
| | - Ya-Chi Chang
- National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan
- Department of Oncology, National Taiwan University Hospital, Taipei, Taiwan
| | - Liang-In Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jun-Yang Liou
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Chiun Hsu
- Department of Oncology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Ann-Lii Cheng
- Graduate Institute of Oncology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Oncology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Graduate Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
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Silva-Santisteban MC, Westwood IM, Boxall K, Brown N, Peacock S, McAndrew C, Barrie E, Richards M, Mirza A, Oliver AW, Burke R, Hoelder S, Jones K, Aherne GW, Blagg J, Collins I, Garrett MD, van Montfort RLM. Fragment-based screening maps inhibitor interactions in the ATP-binding site of checkpoint kinase 2. PLoS One 2013; 8:e65689. [PMID: 23776527 PMCID: PMC3680490 DOI: 10.1371/journal.pone.0065689] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 04/26/2013] [Indexed: 01/15/2023] Open
Abstract
Checkpoint kinase 2 (CHK2) is an important serine/threonine kinase in the cellular response to DNA damage. A fragment-based screening campaign using a combination of a high-concentration AlphaScreen™ kinase assay and a biophysical thermal shift assay, followed by X-ray crystallography, identified a number of chemically different ligand-efficient CHK2 hinge-binding scaffolds that have not been exploited in known CHK2 inhibitors. In addition, it showed that the use of these orthogonal techniques allowed efficient discrimination between genuine hit matter and false positives from each individual assay technology. Furthermore, the CHK2 crystal structures with a quinoxaline-based fragment and its follow-up compound highlight a hydrophobic area above the hinge region not previously explored in rational CHK2 inhibitor design, but which might be exploited to enhance both potency and selectivity of CHK2 inhibitors.
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Affiliation(s)
- M. Cris Silva-Santisteban
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
- Division of Structural Biology, The Institute of Cancer Research, Chester Beatty Laboratories, Chelsea, London, United Kingdom
| | - Isaac M. Westwood
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
- Division of Structural Biology, The Institute of Cancer Research, Chester Beatty Laboratories, Chelsea, London, United Kingdom
| | - Kathy Boxall
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Nathan Brown
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Sam Peacock
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Craig McAndrew
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Elaine Barrie
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Meirion Richards
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Amin Mirza
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Antony W. Oliver
- Division of Structural Biology, The Institute of Cancer Research, Chester Beatty Laboratories, Chelsea, London, United Kingdom
| | - Rosemary Burke
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Swen Hoelder
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Keith Jones
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - G. Wynne Aherne
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Julian Blagg
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Ian Collins
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Michelle D. Garrett
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
| | - Rob L. M. van Montfort
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, United Kingdom
- Division of Structural Biology, The Institute of Cancer Research, Chester Beatty Laboratories, Chelsea, London, United Kingdom
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120
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Bologna S, Ferrari S. It takes two to tango: Ubiquitin and SUMO in the DNA damage response. Front Genet 2013; 4:106. [PMID: 23781231 PMCID: PMC3678106 DOI: 10.3389/fgene.2013.00106] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 05/24/2013] [Indexed: 11/14/2022] Open
Abstract
The complexity of living cells is primarily determined by the genetic information encoded in DNA and gets fully disclosed upon translation. A major determinant of complexity is the reversible post-translational modification (PTM) of proteins, which generates variants displaying distinct biological properties such as subcellular localization, enzymatic activity and the ability to assemble in complexes. Decades of work on phosphorylation have unambiguously proven this concept. In recent years, the covalent attachment of Ubiquitin or Small Ubiquitin-like Modifiers (SUMO) to amino acid residues of target proteins has been recognized as another crucial PTM, re-directing protein fate and protein-protein interactions. This review focuses on the role of ubiquitylation and sumoylation in the control of DNA damage response proteins. To lay the ground, we begin with a description of ubiquitylation and sumoylation, providing established examples of DNA damage response elements that are controlled through these PTMs. We then examine in detail the role of PTMs in the cellular response to DNA double-strand breaks illustrating hierarchy, cross-talk, synergism or antagonism between phosphorylation, ubiquitylation and sumoylation. We conclude offering a perspective on Ubiquitin and SUMO pathways as targets in cancer therapy.
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Affiliation(s)
- Serena Bologna
- Institute of Molecular Cancer Research, University of ZurichZurich, Switzerland
| | - Stefano Ferrari
- Institute of Molecular Cancer Research, University of ZurichZurich, Switzerland
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Abud J, Koehler-Santos P, Ashton-Prolla P, Prolla JC. CHEK2 1100DELC germline mutation: a frequency study in hereditary breast and colon cancer Brazilian families. ARQUIVOS DE GASTROENTEROLOGIA 2013; 49:273-8. [PMID: 23329222 DOI: 10.1590/s0004-28032012000400008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 09/12/2012] [Indexed: 01/31/2023]
Abstract
CONTEXT CHEK2 encodes a cell cycle checkpoint kinase that plays an important role in the DNA damage repair pathway, activated mainly by ATM (Ataxia Telangiectasia Mutated) in response to double-stranded DNA breaks. A germline mutation in CHEK2, 1100delC, has been described as a low penetrance allele in a significant number of families with breast and colorectal cancer in certain countries and is also associated with increased risk of contralateral breast cancer in women previously affected by the disease. About 5%-10% of all breast and colorectal cancers are associated with hereditary predisposition and its recognition is of great importance for genetic counseling and cancer risk management. OBJECTIVES Here, we have assessed the frequency of the CHEK2 1100delC mutation in the germline of 59 unrelated Brazilian individuals with clinical criteria for the hereditary breast and colorectal cancer syndrome. METHODS A long-range PCR strategy followed by gene sequencing was used. RESULTS The 1100delC mutation was encountered in the germline of one (1.7%) individual in this high risk cohort. This indicates that the CHEK2 1100delC is not commonly encountered in Brazilian families with multiple diagnoses of breast and colorectal cancer. CONCLUSION These results should be confirmed in a larger series of families and further testing should be undertaken to investigate the molecular mechanisms underlying the hereditary breast and colorectal cancer phenotype.
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Affiliation(s)
- Jamile Abud
- Programa de Pós-Graduação em Medicina: Ciências Gastroenterológicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Newly synthesized quinazolinone HMJ-38 suppresses angiogenetic responses and triggers human umbilical vein endothelial cell apoptosis through p53-modulated Fas/death receptor signaling. Toxicol Appl Pharmacol 2013; 269:150-62. [DOI: 10.1016/j.taap.2013.03.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 03/09/2013] [Accepted: 03/12/2013] [Indexed: 01/28/2023]
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123
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Scafoglio C, Smolka M, Zhou H, Perissi V, Rosenfeld MG. The co-repressor SMRT delays DNA damage-induced caspase activation by repressing pro-apoptotic genes and modulating the dynamics of checkpoint kinase 2 activation. PLoS One 2013; 8:e59986. [PMID: 23690919 PMCID: PMC3656868 DOI: 10.1371/journal.pone.0059986] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 02/23/2013] [Indexed: 12/31/2022] Open
Abstract
Checkpoint kinase 2 (Chk2) is a major regulator of DNA damage response and can induce alternative cellular responses: cell cycle arrest and DNA repair or programmed cell death. Here, we report the identification of a new role of Chk2 in transcriptional regulation that also contributes to modulating the balance between survival and apoptosis following DNA damage. We found that Chk2 interacts with members of the NCoR/SMRT transcriptional co-regulator complexes and serves as a functional component of the repressor complex, being required for recruitment of SMRT on the promoter of pro-apoptotic genes upon DNA damage. Thus, the co-repressor SMRT exerts a critical protective action against genotoxic stress-induced caspase activation, repressing a functionally important cohort of pro-apoptotic genes. Amongst them, SMRT is responsible for basal repression of Wip1, a phosphatase that de-phosphorylates and inactivates Chk2, thus affecting a feedback loop responsible for licensing the correct timing of Chk2 activation and the proper execution of the DNA repair process.
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Affiliation(s)
- Claudio Scafoglio
- Howard Hughes Medical Institute and School of Medicine, University of California San Diego, La Jolla, California, United States of America
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail: (CS); (MGR)
| | - Marcus Smolka
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
| | - Huilin Zhou
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Valentina Perissi
- Howard Hughes Medical Institute and School of Medicine, University of California San Diego, La Jolla, California, United States of America
- School of Medicine, Boston University, Boston, Massachusetts, United States of America
| | - Michael G. Rosenfeld
- Howard Hughes Medical Institute and School of Medicine, University of California San Diego, La Jolla, California, United States of America
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail: (CS); (MGR)
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CHEK2*1100delC homozygosity in the Netherlands--prevalence and risk of breast and lung cancer. Eur J Hum Genet 2013; 22:46-51. [PMID: 23652375 DOI: 10.1038/ejhg.2013.85] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 03/30/2013] [Accepted: 04/03/2013] [Indexed: 12/22/2022] Open
Abstract
The 1100delC mutation in the CHEK2 gene has a carrier frequency of up to 1.5% in individuals from North-West Europe. Women heterozygous for 1100delC have an increased breast cancer risk (odds ratio 2.7). To explore the prevalence and clinical consequences of 1100delC homozygosity in the Netherlands, we genotyped a sporadic breast cancer hospital-based cohort, a group of non-BRCA1/2 breast cancer families, and breast tumors from a tumor tissue bank. Three 1100delC homozygous patients were found in the cohort of 1434 sporadic breast cancer patients, suggesting an increased breast cancer risk for 1100delC homozygotes (odds ratio 3.4, 95% confidence interval 0.4-32.6, P=0.3). Another 1100delC homozygote was found in 592 individuals from 108 non-BRCA1/2 breast cancer families, and two more were found after testing 1706 breast tumors and confirming homozygosity on their wild-type DNA. Follow-up data was available for five homozygous patients, and remarkably, three of them had developed contralateral breast cancer. A possible relationship between 1100delC and lung cancer risk was investigated in 457 unrelated lung cancer patients but could not be confirmed. Due to the small number of 1100delC homozygotes identified, the breast cancer risk estimate associated with this genotype had limited accuracy but is probably higher than the risk in heterozygous females. Screening for CHEK2 1100delC could be beneficial in countries with a relatively high allele frequency.
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125
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Ullah M, Stich S, Notter M, Eucker J, Sittinger M, Ringe J. Transdifferentiation of mesenchymal stem cells-derived adipogenic-differentiated cells into osteogenic- or chondrogenic-differentiated cells proceeds via dedifferentiation and have a correlation with cell cycle arresting and driving genes. Differentiation 2013; 85:78-90. [PMID: 23644554 DOI: 10.1016/j.diff.2013.02.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 12/18/2012] [Accepted: 02/05/2013] [Indexed: 01/25/2023]
Abstract
It is generally accepted that after differentiation bone marrow mesenchymal stem cells (MSC) become lineage restricted and unipotent in an irreversible manner. However, current results imply that even terminally differentiated cells transdifferentiate across lineage boundaries and therefore act as a progenitor cells for other lineages. This leads to the questions that whether transdifferentiation occurs via direct cell-to-cell conversion or dedifferentiation to a progenitor cells and subsequent differentiation, and whether MSC potency decreases or increases during differentiation. To address these questions, MSC were differentiated into adipogenic lineage cells, followed by dedifferentiation. The process of dedifferentiation was also confirmed by single cell clonal analysis. Finally the dedifferentiated cells were used for adipogenesis, osteogenesis and chondrogenesis. Histology, FACS, qPCR and GeneChip analyses of undifferentiated MSC, adipogenic-differentiated and dedifferentiated cells were performed. Interestingly, gene profiling and bioinformatics demonstrated that upregulation (DHCR24, G0S2, MAP2K6, SESN3) and downregulation (DST, KAT2, MLL5, RB1, SMAD3, ZAK) of distinct genes have an association with cell cycle arrest in adipogenic-differentiated cells and perhaps narrow down the lineage potency. However, the upregulation (CCND1, CHEK, HGF, HMGA2, SMAD3) and downregulation (CCPG1, RASSF4, RGS2) of these genes have an association with cell cycle progression and maybe motivate dedifferentiation of adipogenic-differentiated cells. We found that dedifferentiated cells have a multilineage potency comparable to MSC, and also observed the associative role of proliferation genes with cell cycle arrest and progression. Concluded, our results indicate that transdifferentiation of adipogenic-differentiated cells into osteogenic- or chondrogenic-differentiated cells proceeds via dedifferentiation and correlates with cell cycle arresting and deriving genes. Regarding clinical use, the knowledge of potency and underlying mechanisms are prerequisites.
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Affiliation(s)
- Mujib Ullah
- Tissue Engineering Laboratory & Berlin-Brandenburg Center for Regenerative Therapies, Dept. of Rheumatology and Clinical Immunology, Charité-University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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Ohsugi T, Ishida T, Shimasaki T, Okada S, Umezawa K. p53 dysfunction precedes the activation of nuclear factor-κB during disease progression in mice expressing Tax, a human T-cell leukemia virus type 1 oncoprotein. Carcinogenesis 2013; 34:2129-36. [PMID: 23633516 DOI: 10.1093/carcin/bgt144] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Transgenic (Tg) mice expressing Tax, a human T-cell leukemia virus type 1 (HTLV-1) oncoprotein, develop mature T-cell leukemia/lymphoma. The leukemic cells in Tg mice expressing Tax show p53 dysfunction and nuclear factor-κB (NF-κB) activation, similar to that seen in adult T-cell leukemia/lymphoma (ATLL) cells from patients infected with HTLV-1. However, it is unclear when these effects occur in HTLV-1 carriers during the development of ATLL. Here, we examined p53 function and NF-κB activity before the onset of leukemia in Tax-expressing Tg (Tax-Tg) mice between 4 and 25 months of age. At 4-10 months of age, 71% of mice showed p53 inactivation, without evidence for NF-κB activation, even though tax expression was consistent from 4 to 25 months of age. The decline in p53 function resulted from decreased p53 accumulation after DNA damage. From 11 months of age onward, 75% of mice showed p53 dysfunction and 37.5% showed constitutive NF-κB activation with the components of p50 and RelB. An NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), reduced NF-κB activity (i.e. p50/RelB) but did not restore p53 function. In vivo, treatment with DHMEQ until 24 months of age prevented the onset of T-cell leukemia in Tax-Tg mice. These results suggest that the Tax-induced decline in p53 function, which is independent of NF-κB activation in the early stage, might be the first stage in the onset of ATLL. NF-κB activity is involved in the later stages of ATLL onset.
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Affiliation(s)
- Takeo Ohsugi
- Division of Microbiology and Genetics, Institute of Resource Development and Analysis, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan
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Mendoza J, Sekiya M, Taniguchi T, Iijima KM, Wang R, Ando K. Global analysis of phosphorylation of tau by the checkpoint kinases Chk1 and Chk2 in vitro. J Proteome Res 2013; 12:2654-65. [PMID: 23550703 DOI: 10.1021/pr400008f] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hyperphosphorylation of microtubule-associated protein tau is thought to contribute to Alzheimer's disease (AD) pathogenesis. We previously showed that DNA damage-activated cell cycle checkpoint kinases Chk1 and Chk2 phosphorylate tau at an AD-related site and enhance tau toxicity, suggesting potential roles of these kinases in AD. The purpose of this study is to systematically identify which sites in tau are directly phosphorylated by Chk1 and Chk2. Using recombinant human tau phosphorylated by Chk1 and Chk2 in vitro, we first analyzed tau phosphorylation at the AD-related sites by Western blot with phospho-tau-specific antibodies. Second, to globally identify phosphorylated sites in tau, liquid chromatography-tandem mass spectrometry (LC-MS(3)) was employed. These systematic analyses identified a total of 27 Ser/Thr residues as Chk1- or Chk2- target sites. None of them were proline-directed kinase targets. Many of these sites are located within the microtubule-binding domain and C-terminal domain, whose phosphorylation has been shown to reduce tau binding to microtubules and/or has been implicated in tau toxicity. Among these 27 sites, 13 sites have been identified to be phosphorylated in AD brains. Since DNA damage is accumulated in diseased brains, Chk1 and Chk2 may be involved in tau phosphorylation and toxicity in AD pathogenesis.
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Affiliation(s)
- Jhoana Mendoza
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, 1425 Madison Avenue, Box 1498, New York, New York 10029, United States
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Matthews TP, Jones AM, Collins I. Structure-based design, discovery and development of checkpoint kinase inhibitors as potential anticancer therapies. Expert Opin Drug Discov 2013; 8:621-40. [PMID: 23594139 DOI: 10.1517/17460441.2013.788496] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Checkpoint kinase (CHK) inhibitors offer the promise of enhancing the effectiveness of widely prescribed cancer chemotherapies and radiotherapy by inhibiting the DNA damage response, as well as the potential for single agent efficacy. AREAS COVERED This article surveys structural insights into the checkpoint kinases CHK1 and CHK2 that have been exploited to enhance the selectivity and potency of small molecule inhibitors. Furthermore, the authors review the use of mechanistic cellular assays to guide the optimisation of inhibitors. Finally, the authors discuss the status of the current clinical candidates and emerging new clinical contexts for CHK1 and CHK2 inhibitors, including the prospects for single agent efficacy. EXPERT OPINION Protein-bound water molecules play key roles in structural features that can be targeted to gain high selectivity for either enzyme. The results of early phase clinical trials of checkpoint inhibitors have been mixed, but significant progress has been made in testing the combination of CHK1 inhibitors with genotoxic chemotherapy. Second-generation CHK1 inhibitors are likely to benefit from increased selectivity and oral bioavailability. While the optimum therapeutic context for CHK2 inhibition remains unclear, the emergence of single agent preclinical efficacy for CHK1 inhibitors in specific tumour types exhibiting constitutive replication stress represents exciting progress in exploring the therapeutic potential of these agents.
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Affiliation(s)
- Thomas P Matthews
- Institute of Cancer Research, Cancer Research UK Cancer Therapeutics Unit, London SM2 5NG, UK
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Abstract
Mitotic catastrophe, which refers to cell death or its prologue triggered by aberrant mitosis, can be induced by a heterogeneous group of stimuli, including chromosome damage or perturbation of the mitotic apparatus. We investigated the mechanism of mitotic catastrophe and cell death induced by depletion of centrosomal proteins that perturbs microtubule organization. We transfected cells harboring wild-type or mutated p53 with siRNAs targeting Aurora A, ninein, TOG, TACC3, γ-tubulin, or pericentriolar material-1, and monitored the effects on cell death. Knockdown of Aurora A, ninein, TOG, and TACC3 led to cell death, regardless of p53 status. Knockdown of Aurora A, ninein, and TOG, led to aberrant spindle formation and subsequent cell death, which was accompanied by several features of apoptosis, including nuclear condensation and Annexin V binding in HeLa cells. During this process, cleavage of poly(ADP-ribose) polymerase-1, caspase-3, and caspase-9 was detected, but cleavage of caspase-8 was not. Cell death, monitored by time-lapse imaging, occurred during both interphase and M phase. In cells depleted of a centrosomal protein (Aurora A, ninein, or TOG), the rate of cell death was higher if the cells were cotransfected with siRNA against BubR1 or Mad2 than if they were transfected with siRNA against Bub1 or a control siRNA. These results suggest that metaphase arrest is necessary for the mitotic catastrophe and cell death caused by depletion of centrosomal proteins. Knockdown of centrosomal proteins led to increased phosphorylation of Chk2. Enhanced p-Chk2 localization was also observed at the centrosome in cells arrested in M phase, as well as in the nuclei of dying cells. Cotransfection of siRNAs against Chk2, in combination with depletion of a centrosomal protein, decreased the amount of cell death. Thus, Chk2 activity is indispensable for apoptosis after mitotic catastrophe induced by depletion of centrosomal proteins that perturbs microtubule organization.
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130
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Li WQ, Hu N, Hyland PL, Gao Y, Wang ZM, Yu K, Su H, Wang CY, Wang LM, Chanock SJ, Burdett L, Ding T, Qiao YL, Fan JH, Wang Y, Xu Y, Shi JX, Gu F, Wheeler W, Xiong XQ, Giffen C, Tucker MA, Dawsey SM, Freedman ND, Abnet CC, Goldstein AM, Taylor PR. Genetic variants in DNA repair pathway genes and risk of esophageal squamous cell carcinoma and gastric adenocarcinoma in a Chinese population. Carcinogenesis 2013; 34:1536-42. [PMID: 23504502 DOI: 10.1093/carcin/bgt094] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The DNA repair pathways help to maintain genomic integrity and therefore genetic variation in the pathways could affect the propensity to develop cancer. Selected germline single nucleotide polymorphisms (SNPs) in the pathways have been associated with esophageal cancer and gastric cancer (GC) but few studies have comprehensively examined the pathway genes. We aimed to investigate associations between DNA repair pathway genes and risk of esophageal squamous cell carcinoma (ESCC) and GC, using data from a genome-wide association study in a Han Chinese population where ESCC and GC are the predominant cancers. In sum, 1942 ESCC cases, 1758 GC cases and 2111 controls from the Shanxi Upper Gastrointestinal Cancer Genetics Project (discovery set) and the Linxian Nutrition Intervention Trials (replication set) were genotyped for 1675 SNPs in 170 DNA repair-related genes. Logistic regression models were applied to evaluate SNP-level associations. Gene- and pathway-level associations were determined using the resampling-based adaptive rank-truncated product approach. The DNA repair pathways overall were significantly associated with risk of ESCC (P = 6.37 × 10(-4)), but not with GC (P = 0.20). The most significant gene in ESCC was CHEK2 (P = 2.00 × 10(-6)) and in GC was CLK2 (P = 3.02 × 10(-4)). We observed several other genes significantly associated with either ESCC (SMUG1, TDG, TP53, GTF2H3, FEN1, POLQ, HEL308, RAD54B, MPG, FANCE and BRCA1) or GC risk (MRE11A, RAD54L and POLE) (P < 0.05). We provide evidence for an association between specific genes in the DNA repair pathways and the risk of ESCC and GC. Further studies are warranted to validate these associations and to investigate underlying mechanisms.
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Affiliation(s)
- Wen-Qing Li
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, MD 20852, USA.
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131
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Abstract
The serine threonine kinase checkpoint kinase 2 (CHK2) is a DNA damage checkpoint protein important for the ATM-p53 signaling pathway. In addition to its phosphorylation, CHK2 is also ubiquitylated, and both post-translational modifications are important for its function. However, although the mechanisms that regulate CHK2 phosphorylation are well established, those that control its ubiquitylation are not fully understood. In this study, we demonstrate that the ubiquitin E3 ligase PIRH2 (p53-induced protein with a RING (Really Interesting New Gene)-H2 domain) interacts with CHK2 and mediates its polyubiquitylation and proteasomal degradation. We show that the deubiquitylating enzyme USP28 forms a complex with PIRH2 and CHK2 and antagonizes PIRH2-mediated polyubiquitylation and proteasomal degradation of CHK2. We also provide evidence that CHK2 ubiquitylation by PIRH2 is dependent on its phosphorylation status. Cells deficient in Pirh2 displayed accumulation of Chk2 and enhanced hyperactivation of G1/S and G2/M cell-cycle checkpoints. This hyperactivation was, however, no longer observed in Pirh2-/-Chk2-/- cells, providing evidence for the importance of Chk2 regulation by Pirh2. These findings indicate that PIRH2 has central roles in the ubiquitylation of Chk2 and its turnover and in the regulation of its function.
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132
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Excess breast cancer risk in first degree relatives of CHEK2∗1100delC positive familial breast cancer cases. Eur J Cancer 2013; 49:1993-9. [PMID: 23415889 DOI: 10.1016/j.ejca.2013.01.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/14/2013] [Accepted: 01/15/2013] [Indexed: 11/22/2022]
Abstract
AIM The CHEK2∗1100delC mutation confers a relative risk of two for breast cancer (BC) in the general population. This study aims to explore the excess cancer risk due to the CHEK2∗1100delC mutation within a familial non-BRCA1/2 breast cancer setting. PATIENTS AND METHODS Cancer incidences were compared between first degree relatives of 107 familial breast cancer patients positive for the CHEK2∗1100delC mutation (CHEK2 positive families) and first degree relatives of 314 familial breast cancer patients without the CHEK2∗1100delC mutation (CHEK2 negative families). All families were derived from the same pool of familial non-BRCA1/2 breast cancer families (n=2554). Medical information of 2188 first degree relatives of these families was analysed for cancer risk. CHEK2∗1100delC status of relatives was unknown. RESULTS Increased breast cancer risk (hazard ratio (HR) 2.0 (95% confidence interval (CI): 1.4-2.7), p<0.001) was observed in sisters of CHEK2∗1100delC positive index cases compared to sisters of CHEK2∗1100delC negative index cases. HR was 1.6 (95% CI: 1.0-2.4) for mothers of CHEK2 positive versus negative index cases (p=0.041). For second primary breast cancers HR was increased in CHEK2∗1100delC positive index cases (HR 2.1, 95% CI: 1.3-3.3, p=0.003) and their sisters (HR 2.6, 95% CI: 1.1-6.1, p=0.025). CONCLUSION There is an excess breast cancer risk in first degree relatives of CHEK2∗1100delC positive non-BRCA1/2 familial breast cancer patients compared to non-CHEK2∗1100delC familial breast cancer relatives. Genotyping for the CHEK2∗1100delC mutation in a familial breast cancer setting contributes to optimal clinical surveillance in countries in which this mutation is prevalent. Carriers and female relatives are eligible for stringent breast surveillance programs.
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133
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Kim SO, Sakchaisri K, N. R. T, Soung NK, Jang JH, Kim YS, Lee KS, Kwon YT, Asami Y, Ahn JS, Erikson RL, Kim BY. STK295900, a dual inhibitor of topoisomerase 1 and 2, induces G(2) arrest in the absence of DNA damage. PLoS One 2013; 8:e53908. [PMID: 23349762 PMCID: PMC3551932 DOI: 10.1371/journal.pone.0053908] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 12/04/2012] [Indexed: 11/18/2022] Open
Abstract
STK295900, a small synthetic molecule belonging to a class of symmetric bibenzimidazoles, exhibits antiproliferative activity against various human cancer cell lines from different origins. Examining the effect of STK295900 in HeLa cells indicates that it induces G(2) phase arrest without invoking DNA damage. Further analysis shows that STK295900 inhibits DNA relaxation that is mediated by topoisomerase 1 (Top 1) and topoisomerase 2 (Top 2) in vitro. In addition, STK295900 also exhibits protective effect against DNA damage induced by camptothecin. However, STK295900 does not affect etoposide-induced DNA damage. Moreover, STK295900 preferentially exerts cytotoxic effect on cancer cell lines while camptothecin, etoposide, and Hoechst 33342 affected both cancer and normal cells. Therefore, STK295900 has a potential to be developed as an anticancer chemotherapeutic agent.
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Affiliation(s)
- Sun-Ok Kim
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang, Cheongwon, Korea
- Department of Biochemistry, College of Natural Sciences, ChungNam National University, Yuseonggu, Daejeon, Korea
| | - Krisada Sakchaisri
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang, Cheongwon, Korea
| | - Thimmegowda N. R.
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang, Cheongwon, Korea
| | - Nak Kyun Soung
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang, Cheongwon, Korea
| | - Jae-Hyuk Jang
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang, Cheongwon, Korea
| | - Young Sang Kim
- Department of Biochemistry, College of Natural Sciences, ChungNam National University, Yuseonggu, Daejeon, Korea
| | - Kyung Sang Lee
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yong Tae Kwon
- World Class University (WCU), Graduate School of Convergence Science and Technology and College of Medicine, Seoul National University, Seoul, Korea
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, School of Pharmacy, Universigy of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Yukihiro Asami
- Chemical Biology Department, RIKEN Advanced Science Institute, Wako-shi, Saitama, Japan
| | - Jong Seog Ahn
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang, Cheongwon, Korea
| | - Raymond Leo Erikson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Bo Yeon Kim
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang, Cheongwon, Korea
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134
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Bayram S, Akkız H, Topaktaş M. CHK2 1100delC, IVS2+1G>A and I157T mutations are not present in hepatocellular cancer cases from a Turkish population. Gene 2013; 512:232-6. [DOI: 10.1016/j.gene.2012.10.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 10/11/2012] [Accepted: 10/16/2012] [Indexed: 01/17/2023]
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135
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Wierstra I. FOXM1 (Forkhead box M1) in tumorigenesis: overexpression in human cancer, implication in tumorigenesis, oncogenic functions, tumor-suppressive properties, and target of anticancer therapy. Adv Cancer Res 2013; 119:191-419. [PMID: 23870513 DOI: 10.1016/b978-0-12-407190-2.00016-2] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor and is also intimately involved in tumorigenesis. FOXM1 stimulates cell proliferation and cell cycle progression by promoting the entry into S-phase and M-phase. Additionally, FOXM1 is required for proper execution of mitosis. In accordance with its role in stimulation of cell proliferation, FOXM1 exhibits a proliferation-specific expression pattern and its expression is regulated by proliferation and anti-proliferation signals as well as by proto-oncoproteins and tumor suppressors. Since these factors are often mutated, overexpressed, or lost in human cancer, the normal control of the foxm1 expression by them provides the basis for deregulated FOXM1 expression in tumors. Accordingly, FOXM1 is overexpressed in many types of human cancer. FOXM1 is intimately involved in tumorigenesis, because it contributes to oncogenic transformation and participates in tumor initiation, growth, and progression, including positive effects on angiogenesis, migration, invasion, epithelial-mesenchymal transition, metastasis, recruitment of tumor-associated macrophages, tumor-associated lung inflammation, self-renewal capacity of cancer cells, prevention of premature cellular senescence, and chemotherapeutic drug resistance. However, in the context of urethane-induced lung tumorigenesis, FOXM1 has an unexpected tumor suppressor role in endothelial cells because it limits pulmonary inflammation and canonical Wnt signaling in epithelial lung cells, thereby restricting carcinogenesis. Accordingly, FOXM1 plays a role in homologous recombination repair of DNA double-strand breaks and maintenance of genomic stability, that is, prevention of polyploidy and aneuploidy. The implication of FOXM1 in tumorigenesis makes it an attractive target for anticancer therapy, and several antitumor drugs have been reported to decrease FOXM1 expression.
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136
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Abstract
Dysregulation of DNA damage repair and signalling to cell cycle checkpoints, known as the DNA damage response (DDR), is associated with a predisposition to cancer and affects responses to DNA-damaging anticancer therapy. Dysfunction of one DNA repair pathway may be compensated for by the function of another compensatory DDR pathway, which may be increased and contribute to resistance to DNA-damaging chemotherapy and radiotherapy. Therefore, DDR pathways make an ideal target for therapeutic intervention; first, to prevent or reverse therapy resistance; and second, using a synthetic lethal approach to specifically kill cancer cells that are dependent on a compensatory DNA repair pathway for survival in the context of cancer-associated oxidative and replicative stress. These hypotheses are currently being tested in the laboratory and are being translated into clinical studies.
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Affiliation(s)
- Nicola J Curtin
- Newcastle University, Northern Institute for Cancer Research, Newcastle upon Tyne NE2 4HH, UK.
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137
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SUN XIN, LIU BIN, WANG JIN, LI JUN, JI WENYUE. Inhibition of p21-activated kinase 4 expression suppresses the proliferation of Hep-2 laryngeal carcinoma cells via activation of the ATM/Chk1/2/p53 pathway. Int J Oncol 2012; 42:683-9. [DOI: 10.3892/ijo.2012.1718] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 11/12/2012] [Indexed: 11/06/2022] Open
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138
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Matijssen C, Silva-Santisteban MC, Westwood IM, Siddique S, Choi V, Sheldrake P, van Montfort RL, Blagg J. Benzimidazole inhibitors of the protein kinase CHK2: clarification of the binding mode by flexible side chain docking and protein-ligand crystallography. Bioorg Med Chem 2012; 20:6630-9. [PMID: 23058106 PMCID: PMC3778940 DOI: 10.1016/j.bmc.2012.09.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 09/07/2012] [Accepted: 09/13/2012] [Indexed: 11/23/2022]
Abstract
Two closely related binding modes have previously been proposed for the ATP-competitive benzimidazole class of checkpoint kinase 2 (CHK2) inhibitors; however, neither binding mode is entirely consistent with the reported SAR. Unconstrained rigid docking of benzimidazole ligands into representative CHK2 protein crystal structures reveals an alternative binding mode involving a water-mediated interaction with the hinge region; docking which incorporates protein side chain flexibility for selected residues in the ATP binding site resulted in a refinement of the water-mediated hinge binding mode that is consistent with observed SAR. The flexible docking results are in good agreement with the crystal structures of four exemplar benzimidazole ligands bound to CHK2 which unambiguously confirmed the binding mode of these inhibitors, including the water-mediated interaction with the hinge region, and which is significantly different from binding modes previously postulated in the literature.
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Key Words
- adp, adenosine diphosphate
- atm, ataxia telangiectasia mutated
- atp, adenosine triphosphate
- chk2, checkpoint kinase 2
- gold, genetic optimisation for ligand docking
- gst, glutathione s-transferase
- kd, kinase domain
- moe, molecular operating environment
- parp, poly adp-ribose polymerase
- pdb, protein data bank
- plif, protein ligand interaction fingerprints
- sar, structure activity relationship
- sift, structural interaction fingerprints
- kinase
- chk2
- flexible docking
- crystallography
- inhibitor
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Affiliation(s)
- Cornelis Matijssen
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey SM2 5NG, UK
| | - M. Cris Silva-Santisteban
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey SM2 5NG, UK
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, Chelsea, London SW3 6JB, UK
| | - Isaac M. Westwood
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey SM2 5NG, UK
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, Chelsea, London SW3 6JB, UK
| | - Samerene Siddique
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey SM2 5NG, UK
| | - Vanessa Choi
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey SM2 5NG, UK
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, Chelsea, London SW3 6JB, UK
| | - Peter Sheldrake
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey SM2 5NG, UK
| | - Rob L.M. van Montfort
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey SM2 5NG, UK
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, Chelsea, London SW3 6JB, UK
| | - Julian Blagg
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey SM2 5NG, UK
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139
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Budworth H, Snijders AM, Marchetti F, Mannion B, Bhatnagar S, Kwoh E, Tan Y, Wang SX, Blakely WF, Coleman M, Peterson L, Wyrobek AJ. DNA repair and cell cycle biomarkers of radiation exposure and inflammation stress in human blood. PLoS One 2012; 7:e48619. [PMID: 23144912 PMCID: PMC3492462 DOI: 10.1371/journal.pone.0048619] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 09/26/2012] [Indexed: 01/28/2023] Open
Abstract
DNA damage and repair are hallmarks of cellular responses to ionizing radiation. We hypothesized that monitoring the expression of DNA repair-associated genes would enhance the detection of individuals exposed to radiation versus other forms of physiological stress. We employed the human blood ex vivo radiation model to investigate the expression responses of DNA repair genes in repeated blood samples from healthy, non-smoking men and women exposed to 2 Gy of X-rays in the context of inflammation stress mimicked by the bacterial endotoxin lipopolysaccharide (LPS). Radiation exposure significantly modulated the transcript expression of 12 genes of 40 tested (2.2E-06<p<0.03), of which 8 showed no overlap between unirradiated and irradiated samples (CDKN1A, FDXR, BBC3, PCNA, GADD45a, XPC, POLH and DDB2). This panel demonstrated excellent dose response discrimination (0.5 to 8 Gy) in an independent human blood ex vivo dataset, and 100% accuracy for discriminating patients who received total body radiation. Three genes of this panel (CDKN1A, FDXR and BBC3) were also highly sensitive to LPS treatment in the absence of radiation exposure, and LPS co-treatment significantly affected their radiation responses. At the protein level, BAX and pCHK2-thr68 were elevated after radiation exposure, but the pCHK2-thr68 response was significantly decreased in the presence of LPS. Our combined panel yields an estimated 4-group accuracy of ∼90% to discriminate between radiation alone, inflammation alone, or combined exposures. Our findings suggest that DNA repair gene expression may be helpful to identify biodosimeters of exposure to radiation, especially within high-complexity exposure scenarios.
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Affiliation(s)
- Helen Budworth
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Antoine M. Snijders
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Francesco Marchetti
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Brandon Mannion
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Sandhya Bhatnagar
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Ely Kwoh
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Yuande Tan
- Center for Biostatistics, The Methodist Hospital Research Institute, Houston, Texas, United States of America
| | - Shan X. Wang
- Department of Materials Science and Engineering, Department of Electrical Engineering, Stanford University, Stanford, California, United States of America
| | - William F. Blakely
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Matthew Coleman
- Radiation Oncology, UC Davis School of Medicine, University of California Davis, Davis, California, United States of America
| | - Leif Peterson
- Center for Biostatistics, The Methodist Hospital Research Institute, Houston, Texas, United States of America
| | - Andrew J. Wyrobek
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- * E-mail:
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140
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Engagement of the ATR-dependent DNA damage response at the human papillomavirus 18 replication centers during the initial amplification. J Virol 2012; 87:951-64. [PMID: 23135710 DOI: 10.1128/jvi.01943-12] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We have previously demonstrated that the human papillomavirus (HPV) genome replicates effectively in U2OS cells after transfection using electroporation. The transient extrachromosomal replication, stable maintenance, and late amplification of the viral genome could be studied for high- and low-risk mucosal and cutaneous papillomaviruses. Recent findings indicate that the cellular DNA damage response (DDR) is activated during the HPV life cycle and that the viral replication protein E1 might play a role in this process. We used a U2OS cell-based system to study E1-dependent DDR activation and the involvement of these pathways in viral transient replication. We demonstrated that the E1 protein could cause double-strand DNA breaks in the host genome by directly interacting with DNA. This activity leads to the induction of an ATM-dependent signaling cascade and cell cycle arrest in the S and G(2) phases. However, the transient replication of HPV genomes in U2OS cells induces the ATR-dependent pathway, as shown by the accumulation of γH2AX, ATR-interacting protein (ATRIP), and topoisomerase IIβ-binding protein 1 (TopBP1) in viral replication centers. Viral oncogenes do not play a role in this activation, which is induced only through DNA replication or by replication proteins E1 and E2. The ATR pathway in viral replication centers is likely activated through DNA replication stress and might play an important role in engaging cellular DNA repair/recombination machinery for effective replication of the viral genome upon active amplification.
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141
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Lainchbury M, Matthews TP, McHardy T, Boxall KJ, Walton MI, Eve PD, Hayes A, Valenti MR, de Haven Brandon AK, Box G, Aherne GW, Reader JC, Raynaud FI, Eccles SA, Garrett MD, Collins I. Discovery of 3-alkoxyamino-5-(pyridin-2-ylamino)pyrazine-2-carbonitriles as selective, orally bioavailable CHK1 inhibitors. J Med Chem 2012; 55:10229-40. [PMID: 23082860 PMCID: PMC3506129 DOI: 10.1021/jm3012933] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
Inhibitors of checkpoint kinase 1 (CHK1) are of current
interest
as potential antitumor agents, but the most advanced inhibitor series
reported to date are not orally bioavailable. A novel series of potent
and orally bioavailable 3-alkoxyamino-5-(pyridin-2-ylamino)pyrazine-2-carbonitrile
CHK1 inhibitors was generated by hybridization of two lead scaffolds
derived from fragment-based drug design and optimized for CHK1 potency
and high selectivity using a cell-based assay cascade. Efficient in
vivo pharmacokinetic assessment was used to identify compounds with
prolonged exposure following oral dosing. The optimized compound (CCT244747)
was a potent and highly selective CHK1 inhibitor, which modulated
the DNA damage response pathway in human tumor xenografts and showed
antitumor activity in combination with genotoxic chemotherapies and
as a single agent.
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Affiliation(s)
- Michael Lainchbury
- Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, 15 Cotswold Road, Sutton, SM2 5NG U. K
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142
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Wu C, Kraft P, Zhai K, Chang J, Wang Z, Li Y, Hu Z, He Z, Jia W, Abnet CC, Liang L, Hu N, Miao X, Zhou Y, Liu Z, Zhan Q, Liu Y, Qiao Y, Zhou Y, Jin G, Guo C, Lu C, Yang H, Fu J, Yu D, Freedman ND, Ding T, Tan W, Goldstein AM, Wu T, Shen H, Ke Y, Zeng Y, Chanock SJ, Taylor PR, Lin D. Genome-wide association analyses of esophageal squamous cell carcinoma in Chinese identify multiple susceptibility loci and gene-environment interactions. Nat Genet 2012; 44:1090-7. [PMID: 22960999 DOI: 10.1038/ng.2411] [Citation(s) in RCA: 205] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 08/16/2012] [Indexed: 12/13/2022]
Abstract
We conducted a genome-wide association study (GWAS) and a genome-wide gene-environment interaction analysis of esophageal squamous-cell carcinoma (ESCC) in 2,031 affected individuals (cases) and 2,044 controls with independent validation in 8,092 cases and 8,620 controls. We identified nine new ESCC susceptibility loci, of which seven, at chromosomes 4q23, 16q12.1, 17q21, 22q12, 3q27, 17p13 and 18p11, had a significant marginal effect (P=1.78×10(-39) to P=2.49×10(-11)) and two of which, at 2q22 and 13q33, had a significant association only in the gene-alcohol drinking interaction (gene-environment interaction P (PG×E)=4.39×10(-11) and PG×E=4.80×10(-8), respectively). Variants at the 4q23 locus, which includes the ADH cluster, each had a significant interaction with alcohol drinking in their association with ESCC risk (PG×E=2.54×10(-7) to PG×E=3.23×10(-2)). We confirmed the known association of the ALDH2 locus on 12q24 to ESCC, and a joint analysis showed that drinkers with both of the ADH1B and ALDH2 risk alleles had a fourfold increased risk for ESCC compared to drinkers without these risk alleles. Our results underscore the direct genetic contribution to ESCC risk, as well as the genetic contribution to ESCC through interaction with alcohol consumption.
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Affiliation(s)
- Chen Wu
- State Key Laboratory of Molecular Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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143
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Checkpoint kinase 2 (Chk2) inhibits the activity of the Cdc45/MCM2-7/GINS (CMG) replicative helicase complex. Proc Natl Acad Sci U S A 2012; 109:13163-70. [PMID: 22853956 DOI: 10.1073/pnas.1211525109] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The replication of eukaryote chromosomes slows down when DNA is damaged and the proteins that work at the fork (the replisome) are known targets for the signaling pathways that mediate such responses critical for accurate genomic inheritance. However, the molecular mechanisms and details of how this response is mediated are poorly understood. In this report we show that the activity of replisome helicase, the Cdc45/MCM2-7/GINS (CMG) complex, can be inhibited by protein phosphorylation. Recombinant Drosophila melanogaster CMG can be stimulated by treatment with phosphatase whereas Chk2 but not Chk1 interferes with the helicase activity in vitro. The targets for Chk2 phosphorylation have been identified and reside in MCM subunits 3 and 4 and in the GINS protein Psf2. Interference requires a combination of modifications and we suggest that the formation of negative charges might create a surface on the helicase to allosterically affect its function. The treatment of developing fly embryos with ionizing radiation leads to hyperphosphorylation of Psf2 subunit in the active helicase complex. Taken together these data suggest that the direct modification of the CMG helicase by Chk2 is an important nexus for response to DNA damage.
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144
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Alternative splicing of CHEK2 and codeletion with NF2 promote chromosomal instability in meningioma. Neoplasia 2012; 14:20-8. [PMID: 22355270 DOI: 10.1593/neo.111574] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 12/23/2011] [Accepted: 01/03/2012] [Indexed: 12/13/2022] Open
Abstract
Mutations of the NF2 gene on chromosome 22q are thought to initiate tumorigenesis in nearly 50% of meningiomas, and 22q deletion is the earliest and most frequent large-scale chromosomal abnormality observed in these tumors. In aggressive meningiomas, 22q deletions are generally accompanied by the presence of large-scale segmental abnormalities involving other chromosomes, but the reasons for this association are unknown. We find that large-scale chromosomal alterations accumulate during meningioma progression primarily in tumors harboring 22q deletions, suggesting 22q-associated chromosomal instability. Here we show frequent codeletion of the DNA repair and tumor suppressor gene, CHEK2, in combination with NF2 on chromosome 22q in a majority of aggressive meningiomas. In addition, tumor-specific splicing of CHEK2 in meningioma leads to decreased functional Chk2 protein expression. We show that enforced Chk2 knockdown in meningioma cells decreases DNA repair. Furthermore, Chk2 depletion increases centrosome amplification, thereby promoting chromosomal instability. Taken together, these data indicate that alternative splicing and frequent codeletion of CHEK2 and NF2 contribute to the genomic instability and associated development of aggressive biologic behavior in meningiomas.
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145
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Bayram S, Topaktaş M, Akkız H, Bekar A, Akgöllü E. CHEK2 1100delC, IVS2+1G>A and I157T mutations are not present in colorectal cancer cases from Turkish population. Cancer Epidemiol 2012; 36:453-7. [PMID: 22521562 DOI: 10.1016/j.canep.2012.03.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 02/03/2012] [Accepted: 03/19/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND The cell cycle checkpoint kinase 2 (CHEK2) protein participates in the DNA damage response in many cell types. Germline mutations in CHEK2 (1100delC, IVS2+1G>A and I157T) have been impaired serine/threonine kinase activity and associated with a range of cancer types. This hospital-based case-control study aimed to investigate whether CHEK2 1100delC, IVS2+1G>A and I157T mutations play an important role in the development of colorectal cancer (CRC) in Turkish population. METHODS A total of 210 CRC cases and 446 cancer-free controls were genotyped for CHEK2 mutations by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific-polymerase chain reaction (AS-PCR) methods. RESULTS We did not find the CHEK2 1100delC, IVS2+1G>A and I157T mutations in any of the Turkish subjects. CONCLUSION Our result demonstrate for the first time that CHEK2 1100delC, IVS2+1G>A and I157T mutations have not been agenetic susceptibility factor for CRC in the Turkish population. Overall, our data suggest that genotyping of CHEK2 mutations in clinical settings in the Turkish population should not be recommended. However, independent studies are need to validate our findings in a larger series, as well as in patients of different ethnic origins.
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Affiliation(s)
- Süleyman Bayram
- Adıyaman University, Adıyaman School of Health, Department of Nursing, 02040 Adıyaman, Turkey.
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146
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Hu C, Zhang S, Gao X, Gao X, Xu X, Lv Y, Zhang Y, Zhu Z, Zhang C, Li Q, Wong J, Cui Y, Zhang W, Ma L, Wang C. Roles of Kruppel-associated Box (KRAB)-associated Co-repressor KAP1 Ser-473 Phosphorylation in DNA Damage Response. J Biol Chem 2012; 287:18937-52. [PMID: 22496453 DOI: 10.1074/jbc.m111.313262] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The Kruppel-associated box (KRAB)-associated co-repressor KAP1 is an essential nuclear co-repressor for the KRAB zinc finger protein superfamily of transcriptional factors. Ataxia telangiectasia mutated (ATM)-Chk2 and ATM- and Rad3-related (ATR)-Chk1 are two primary kinase signaling cascades activated in response to DNA damage. A growing body of evidence suggests that ATM and ATR phosphorylate KAP1 at Ser-824 in response to DNA damage and regulate KAP1-dependent chromatin condensation, DNA repair, and gene expression. Here, we show that, depending on the type of DNA damage that occurs, KAP1 Ser-473 can be phosphorylated by ATM-Chk2 or ATR-Chk1 kinases. Phosphorylation of KAP1 at Ser-473 attenuated its binding to the heterochromatin protein 1 family proteins and inhibited its transcriptional repression of KRAB-zinc finger protein (KRAB-ZFP) target genes. Moreover, KAP1 Ser-473 phosphorylation induced by DNA damage stimulated KAP1-E2F1 binding. Overexpression of heterochromatin protein 1 significantly inhibited E2F1-KAP1 binding. Elimination of KAP1 Ser-473 phosphorylation increased E2F1-targeted proapoptotic gene expression and E2F1-induced apoptosis in response to DNA damage. Furthermore, loss of phosphorylation of KAP1 Ser-473 led to less BRCA1 focus formation and slower kinetics of loss of γH2AX foci after DNA damage. KAP1 Ser-473 phosphorylation was required for efficient DNA repair and cell survival in response to DNA damage. Our studies reveal novel functions of KAP1 Ser-473 phosphorylation under stress.
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Affiliation(s)
- Chen Hu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and College of Life Science and
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147
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Roeb W, Higgins J, King MC. Response to DNA damage of CHEK2 missense mutations in familial breast cancer. Hum Mol Genet 2012; 21:2738-44. [PMID: 22419737 DOI: 10.1093/hmg/dds101] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Comprehensive sequencing of tumor suppressor genes to evaluate inherited predisposition to cancer yields many individually rare missense alleles of unknown functional and clinical consequence. To address this problem for CHEK2 missense alleles, we developed a yeast-based assay to assess in vivo CHEK2-mediated response to DNA damage. Of 25 germline CHEK2 missense alleles detected in familial breast cancer patients, 12 alleles had complete loss of DNA damage response, 8 had partial loss and 5 exhibited a DNA damage response equivalent to that mediated by wild-type CHEK2. Variants exhibiting reduced response to DNA damage were found in all domains of the CHEK2 protein. Assay results were in agreement with epidemiologic assessments of breast cancer risk for those variants sufficiently common for case-control studies to have been undertaken. Assay results were largely concordant with consensus predictions of in silico tools, particularly for damaging alleles in the kinase domain. However, of the 25 variants, 6 were not consistently classifiable by in silico tools. An in vivo assay of cellular response to DNA damage by mutant CHEK2 alleles may complement and extend epidemiologic and genetic assessment of their clinical consequences.
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Affiliation(s)
- Wendy Roeb
- Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA 98195-7720, USA.
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148
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Feng L, Chen J. The E3 ligase RNF8 regulates KU80 removal and NHEJ repair. Nat Struct Mol Biol 2012; 19:201-6. [PMID: 22266820 DOI: 10.1038/nsmb.2211] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Accepted: 11/21/2011] [Indexed: 12/17/2022]
Abstract
The ubiquitination cascade has a key role in the assembly of repair and signaling proteins at sites of double-strand DNA breaks. The E3 ubiquitin ligase RING finger protein 8 (RNF8) triggers the initial ubiquitination at double-strand DNA breaks, whereas sustained ubiquitination requires the downstream E3 ligase RING finger protein 168 (RNF168). It is not known whether RNF8 and RNF168 have discrete substrates and/or form different ubiquitin chains. Here we show that RNF168 acts with the ubiquitin-conjugating enzyme E2 13 (UBC13) and specifically synthesizes Lys63-linked chains, whereas RNF8 primarily forms Lys48-linked chains on chromatin, which promote substrate degradation. We also find that RNF8 regulates the abundance of the nonhomologous end-joining (NHEJ) repair protein KU80 at sites of DNA damage, and that RNF8 depletion results in prolonged retention of KU80 at damage sites and impaired nonhomologous end-joining repair. These findings reveal a distinct feature of RNF8 and indicate the involvement of the ubiquitination-mediated degradation pathway in DNA damage repair.
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Affiliation(s)
- Lin Feng
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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149
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Nguyen TNT, Saleem RSZ, Luderer MJ, Hovde S, Henry RW, Tepe JJ. Radioprotection by hymenialdisine-derived checkpoint kinase 2 inhibitors. ACS Chem Biol 2012; 7:172-84. [PMID: 22004065 DOI: 10.1021/cb200320c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
DNA damage induced by ionizing radiation activates the ataxia telangiectasia mutated pathway, resulting in apoptosis or DNA repair. The serine/threonine checkpoint kinase (Chk2) is an important transducer of this DNA damage signaling pathway and mediates the ultimate fate of the cell. Chk2 is an advantageous target for the development of adjuvant drugs for cancer therapy, because inhibition of Chk2 allows normal cells to enter cell cycle arrest and DNA repair, whereas many tumors bypass cell cycle checkpoints. Chk2 inhibitors may thus have a radioprotective effect on normal cells. We report herein a class of natural product derived Chk2 inhibitors, exemplified by indoloazepine 1, that elicit a strong ATM-dependent Chk2-mediated radioprotection effect in normal cells and p53 wt cells, but not p53 mutant cells (>50% of all cancers). This study represents the first example of a radioprotective effect in human cells other than T-cells and implicates a functional ATM pathway as a requirement for IR-induced radioprotection by this class of Chk2 inhibitors. Several of the hymenialdisine-derived analogues inhibit Chk2 at nanomolar concentrations, inhibit autophosphorylation of Chk2 at Ser516 in cells, and increase the survival of normal cells following ionizing radiation.
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Affiliation(s)
- Thu N. T. Nguyen
- Department of Chemistry and ‡Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Rahman S. Z. Saleem
- Department of Chemistry and ‡Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Micah J. Luderer
- Department of Chemistry and ‡Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Stacy Hovde
- Department of Chemistry and ‡Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - R. William Henry
- Department of Chemistry and ‡Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jetze J. Tepe
- Department of Chemistry and ‡Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
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Martinez-Rivera M, Siddik ZH. Resistance and gain-of-resistance phenotypes in cancers harboring wild-type p53. Biochem Pharmacol 2011; 83:1049-62. [PMID: 22227014 DOI: 10.1016/j.bcp.2011.12.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 12/02/2011] [Accepted: 12/19/2011] [Indexed: 01/20/2023]
Abstract
Chemotherapy is the bedrock for the clinical management of cancer, and the tumor suppressor p53 has a central role in this therapeutic modality. This protein facilitates favorable antitumor drug response through a variety of key cellular functions, including cell cycle arrest, senescence, and apoptosis. These functions essentially cease once p53 becomes mutated, as occurs in ∼50% of cancers, and some p53 mutants even exhibit gain-of-function effects, which lead to greater drug resistance. However, it is becoming increasingly evident that resistance is also seen in cancers harboring wild-type p53. In this review, we discuss how wild-type p53 is inactivated to render cells resistant to antitumor drugs. This may occur through various mechanisms, including an increase in proteasomal degradation, defects in post-translational modification, and downstream defects in p53 target genes. We also consider evidence that the resistance seen in wild-type p53 cancers can be substantially greater than that seen in mutant p53 cancers, and this poses a far greater challenge for efforts to design strategies that increase drug response in resistant cancers already primed with wild-type p53. Because the mechanisms contributing to this wild-type p53 "gain-of-resistance" phenotype are largely unknown, a concerted research effort is needed to identify the underlying basis for the occurrence of this phenotype and, in parallel, to explore the possibility that the phenotype may be a product of wild-type p53 gain-of-function effects. Such studies are essential to lay the foundation for a rational therapeutic approach in the treatment of resistant wild-type p53 cancers.
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Affiliation(s)
- Michelle Martinez-Rivera
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, 77030, United States
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