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Lee KC, Bramley RL, Cowell IG, Jackson GH, Austin CA. Proteasomal inhibition potentiates drugs targeting DNA topoisomerase II. Biochem Pharmacol 2016; 103:29-39. [PMID: 26794000 PMCID: PMC5071433 DOI: 10.1016/j.bcp.2015.12.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 12/22/2015] [Indexed: 01/15/2023]
Abstract
The reaction mechanism of DNA topoisomerase II (TOP2) involves a covalent double-strand break intermediate in which the enzyme is coupled to DNA via a 5′-phosphotyrosyl bond. This normally transient enzyme-bridged break is stabilised by drugs such as mitoxantrone, mAMSA, etoposide, doxorubicin, epirubicin and idarubicin, which are referred to as TOP2 poisons. Removal of topoisomerase II by the proteasome is involved in the repair of these lesions. In K562 cells, inhibiting the proteasome with MG132 significantly potentiated the growth inhibition by these six drugs that target topoisomerase II, and the highest level of potentiation was observed with mitoxantrone. Mitoxantrone also showed the greatest potentiation by MG132 in three Nalm 6 cell lines with differing levels of TOP2A or TOP2B. Mitoxantrone was also potentiated by the clinically used proteasome inhibitor PS341 (Velcade). We have also shown that proteasome inhibition with MG132 in K562 cells reduces the rate of removal of mitoxantrone or etoposide stabilised topoisomerase complexes from DNA, suggesting a possible mechanism for the potentiation of topoisomerase II drugs by proteasomal inhibition.
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Affiliation(s)
- Ka C Lee
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Rebecca L Bramley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Ian G Cowell
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Graham H Jackson
- Institute for Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Caroline A Austin
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom.
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Hoa NN, Akagawa R, Yamasaki T, Hirota K, Sasa K, Natsume T, Kobayashi J, Sakuma T, Yamamoto T, Komatsu K, Kanemaki MT, Pommier Y, Takeda S, Sasanuma H. Relative contribution of four nucleases, CtIP, Dna2, Exo1 and Mre11, to the initial step of DNA double-strand break repair by homologous recombination in both the chicken DT40 and human TK6 cell lines. Genes Cells 2015; 20:1059-76. [PMID: 26525166 DOI: 10.1111/gtc.12310] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 09/27/2015] [Indexed: 01/26/2023]
Abstract
Homologous recombination (HR) is initiated by double-strand break (DSB) resection, during which DSBs are processed by nucleases to generate 3' single-strand DNA. DSB resection is initiated by CtIP and Mre11 followed by long-range resection by Dna2 and Exo1 in Saccharomyces cerevisiae. To analyze the relative contribution of four nucleases, CtIP, Mre11, Dna2 and Exo1, to DSB resection, we disrupted genes encoding these nucleases in chicken DT40 cells. CtIP and Dna2 are required for DSB resection, whereas Exo1 is dispensable even in the absence of Dna2, which observation agrees with no developmental defect in Exo1-deficient mice. Despite the critical role of Mre11 in DSB resection in S. cerevisiae, loss of Mre11 only modestly impairs DSB resection in DT40 cells. To further test the role of CtIP and Mre11 in other species, we conditionally disrupted CtIP and MRE11 genes in the human TK6 B cell line. As with DT40 cells, CtIP contributes to DSB resection considerably more significantly than Mre11 in TK6 cells. Considering the critical role of Mre11 in HR, this study suggests that Mre11 is involved in a mechanism other than DSB resection. In summary, CtIP and Dna2 are sufficient for DSB resection to ensure efficient DSB repair by HR.
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Affiliation(s)
- Nguyen Ngoc Hoa
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Remi Akagawa
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Tomomi Yamasaki
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Kouji Hirota
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Kentaro Sasa
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Toyoaki Natsume
- Centre for Frontier Research, National Institute of Genetics, ROIS, Yata 1111, Mishima, Shizuoka, 411-8540, Japan
| | - Junya Kobayashi
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Tetsushi Sakuma
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - Kenshi Komatsu
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Masato T Kanemaki
- Centre for Frontier Research, National Institute of Genetics, ROIS, Yata 1111, Mishima, Shizuoka, 411-8540, Japan.,Department of Genetics, SOKENDAI, Yata 1111, Mishima, Shizuoka, 411-8540, Japan.,JST, PREST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Yves Pommier
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Shunichi Takeda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Hiroyuki Sasanuma
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto, 606-8501, Japan
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Evison BJ, Sleebs BE, Watson KG, Phillips DR, Cutts SM. Mitoxantrone, More than Just Another Topoisomerase II Poison. Med Res Rev 2015; 36:248-99. [PMID: 26286294 DOI: 10.1002/med.21364] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 07/13/2015] [Accepted: 07/14/2015] [Indexed: 02/06/2023]
Abstract
Mitoxantrone is a synthetic anthracenedione originally developed to improve the therapeutic profile of the anthracyclines and is commonly applied in the treatment of breast and prostate cancers, lymphomas, and leukemias. A comprehensive overview of the drug's molecular, biochemical, and cellular pharmacology is presented here, beginning with the cardiotoxic nature of its predecessor doxorubicin and how these properties shaped the pharmacology of mitoxantrone itself. Although mitoxantrone is firmly established as a DNA topoisomerase II poison within mammalian cells, it is now clear that the drug interacts with a much broader range of biological macromolecules both covalently and noncovalently. Here, we consider each of these interactions in the context of their wider biological relevance to cancer therapy and highlight how they may be exploited to further enhance the therapeutic value of mitoxantrone. In doing so, it is now clear that mitoxantrone is more than just another topoisomerase II poison.
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Affiliation(s)
- Benny J Evison
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Victoria, 3086, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Keith G Watson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Don R Phillips
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Victoria, 3086, Australia
| | - Suzanne M Cutts
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Victoria, 3086, Australia
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Lafrance-Vanasse J, Williams GJ, Tainer JA. Envisioning the dynamics and flexibility of Mre11-Rad50-Nbs1 complex to decipher its roles in DNA replication and repair. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 117:182-193. [PMID: 25576492 PMCID: PMC4417436 DOI: 10.1016/j.pbiomolbio.2014.12.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 12/20/2014] [Accepted: 12/28/2014] [Indexed: 12/23/2022]
Abstract
The Mre11-Rad50-Nbs1 (MRN) complex is a dynamic macromolecular machine that acts in the first steps of DNA double strand break repair, and each of its components has intrinsic dynamics and flexibility properties that are directly linked with their functions. As a result, deciphering the functional structural biology of the MRN complex is driving novel and integrated technologies to define the dynamic structural biology of protein machinery interacting with DNA. Rad50 promotes dramatic long-range allostery through its coiled-coil and zinc-hook domains. Its ATPase activity drives dynamic transitions between monomeric and dimeric forms that can be modulated with mutants modifying the ATPase rate to control end joining versus resection activities. The biological functions of Mre11's dual endo- and exonuclease activities in repair pathway choice were enigmatic until recently, when they were unveiled by the development of specific nuclease inhibitors. Mre11 dimer flexibility, which may be regulated in cells to control MRN function, suggests new inhibitor design strategies for cancer intervention. Nbs1 has FHA and BRCT domains to bind multiple interaction partners that further regulate MRN. One of them, CtIP, modulates the Mre11 excision activity for homologous recombination repair. Overall, these combined properties suggest novel therapeutic strategies. Furthermore, they collectively help to explain how MRN regulates DNA repair pathway choice with implications for improving the design and analysis of cancer clinical trials that employ DNA damaging agents or target the DNA damage response.
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Affiliation(s)
| | | | - John A Tainer
- Life Science Division, 1 Cyclotron Road, Berkeley, CA 94720, USA; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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The cutting edges in DNA repair, licensing, and fidelity: DNA and RNA repair nucleases sculpt DNA to measure twice, cut once. DNA Repair (Amst) 2014; 19:95-107. [PMID: 24754999 DOI: 10.1016/j.dnarep.2014.03.022] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To avoid genome instability, DNA repair nucleases must precisely target the correct damaged substrate before they are licensed to incise. Damage identification is a challenge for all DNA damage response proteins, but especially for nucleases that cut the DNA and necessarily create a cleaved DNA repair intermediate, likely more toxic than the initial damage. How do these enzymes achieve exquisite specificity without specific sequence recognition or, in some cases, without a non-canonical DNA nucleotide? Combined structural, biochemical, and biological analyses of repair nucleases are revealing their molecular tools for damage verification and safeguarding against inadvertent incision. Surprisingly, these enzymes also often act on RNA, which deserves more attention. Here, we review protein-DNA structures for nucleases involved in replication, base excision repair, mismatch repair, double strand break repair (DSBR), and telomere maintenance: apurinic/apyrimidinic endonuclease 1 (APE1), Endonuclease IV (Nfo), tyrosyl DNA phosphodiesterase (TDP2), UV Damage endonuclease (UVDE), very short patch repair endonuclease (Vsr), Endonuclease V (Nfi), Flap endonuclease 1 (FEN1), exonuclease 1 (Exo1), RNase T and Meiotic recombination 11 (Mre11). DNA and RNA structure-sensing nucleases are essential to life with roles in DNA replication, repair, and transcription. Increasingly these enzymes are employed as advanced tools for synthetic biology and as targets for cancer prognosis and interventions. Currently their structural biology is most fully illuminated for DNA repair, which is also essential to life. How DNA repair enzymes maintain genome fidelity is one of the DNA double helix secrets missed by James Watson and Francis Crick, that is only now being illuminated though structural biology and mutational analyses. Structures reveal motifs for repair nucleases and mechanisms whereby these enzymes follow the old carpenter adage: measure twice, cut once. Furthermore, to measure twice these nucleases act as molecular level transformers that typically reshape the DNA and sometimes themselves to achieve extraordinary specificity and efficiency.
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