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Wang Q, Bode AM, Zhang T. Targeting CDK1 in cancer: mechanisms and implications. NPJ Precis Oncol 2023; 7:58. [PMID: 37311884 DOI: 10.1038/s41698-023-00407-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/25/2023] [Indexed: 06/15/2023] Open
Abstract
Cyclin dependent kinases (CDKs) are serine/threonine kinases that are proposed as promising candidate targets for cancer treatment. These proteins complexed with cyclins play a critical role in cell cycle progression. Most CDKs demonstrate substantially higher expression in cancer tissues compared with normal tissues and, according to the TCGA database, correlate with survival rate in multiple cancer types. Deregulation of CDK1 has been shown to be closely associated with tumorigenesis. CDK1 activation plays a critical role in a wide range of cancer types; and CDK1 phosphorylation of its many substrates greatly influences their function in tumorigenesis. Enrichment of CDK1 interacting proteins with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was conducted to demonstrate that the associated proteins participate in multiple oncogenic pathways. This abundance of evidence clearly supports CDK1 as a promising target for cancer therapy. A number of small molecules targeting CDK1 or multiple CDKs have been developed and evaluated in preclinical studies. Notably, some of these small molecules have also been subjected to human clinical trials. This review evaluates the mechanisms and implications of targeting CDK1 in tumorigenesis and cancer therapy.
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Affiliation(s)
- Qiushi Wang
- The Hormel Institute, University of Minnesota, 801 16th Ave NE, Austin, MN, 55912, USA
| | - Ann M Bode
- The Hormel Institute, University of Minnesota, 801 16th Ave NE, Austin, MN, 55912, USA.
| | - Tianshun Zhang
- The Hormel Institute, University of Minnesota, 801 16th Ave NE, Austin, MN, 55912, USA.
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2
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Chromenopyrimidinone Controls Stemness and Malignancy by suppressing CD133 Expression in Hepatocellular Carcinoma. Cancers (Basel) 2020; 12:cancers12051193. [PMID: 32397206 PMCID: PMC7281429 DOI: 10.3390/cancers12051193] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/17/2020] [Accepted: 04/24/2020] [Indexed: 12/18/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is a highly malignant human cancer that has increasing mortality rates worldwide. Because CD133+ cells control tumor maintenance and progression, compounds that target CD133+ cancer cells could be effective in combating HCC. We found that the administration of chromenopyrimidinone (CPO) significantly decreased spheroid formation and the number of CD133+ cells in mixed HCC cell populations. CPO not only significantly inhibited cell proliferation in HCC cells exhibiting different CD133 expression levels, but also effectively induced apoptosis and increased the expression of LC3-II in HCC cells. CPO also exhibits in vivo therapeutic efficiency in HCC. Specifically, CPO suppressed the expression of CD133 by altering the subcellular localization of CD133 from the membrane to lysosomes in CD133+ HCC cells. Moreover, CPO treatment induced point mutations in the ADRB1, APOB, EGR2, and UBE2C genes and inhibited the expression of these proteins in HCC and the expression of UBE2C is particularly controlled by CD133 expression among those four proteins in HCC. Our results suggested that CPO may suppress stemness and malignancies in vivo and in vitro by decreasing CD133 and UBE2C expression in CD133+ HCC. Our study provides evidence that CPO could act as a novel therapeutic agent for the effective treatment of CD133+ HCC.
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Dasari JB, Soren BC, Ottaviani A, Tesauro C, Marino S, Messina B, Fiorani P. Swapping of The N-Terminal Domain of Human Topoisomerase 1B with the Corresponding Plasmodium Falciparum Counterpart Strongly Impairs Enzyme Activity. Rep Biochem Mol Biol 2020; 8:366-375. [PMID: 32582794 PMCID: PMC7275839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 06/03/2019] [Indexed: 06/11/2023]
Abstract
BACKGROUND DNA topoisomerases 1B are a class of ubiquitous enzyme that solves the topological problems associated with biological processes such as replication, transcription and recombination. Numerous sequence alignment of topoisomerase 1B from different species shows that the lengths of different domains as well as their amino acids sequences are quite different. In the present study a hybrid enzyme, generated by swapping the N-terminal of Plasmodium falciparum into the corresponding domain of the human, has been characterized. METHODS The chimeric enzyme was generated using different sets of PCR. The in vitro characterization was carried out using different DNA substrate including radio-labelled oligonucleotides. RESULTS The chimeric enzyme displayed slower relaxation activity, cleavage and re-ligation kinetics strongly perturbed when compared to the human enzyme. CONCLUSION These results indicate that the N-terminal domain has a crucial role in modulating topoisomerase activity in different species.
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Affiliation(s)
- Jagadish Babu Dasari
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
| | - Bini Chhetri Soren
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
| | - Alessio Ottaviani
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
- Institute of Translational Pharmacology, National Research Council, CNR, Via Del Fosso del Cavaliere 100, Rome 00133, Italy.
| | - Cinzia Tesauro
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
- Present address: Department of Molecular Biology and Genetics, University of Aarhus, C.F MøllersAllè 3, 8000 Aarhus C, Denmark.
| | - Simona Marino
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
| | - Beatrice Messina
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
| | - Paola Fiorani
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy.
- Institute of Translational Pharmacology, National Research Council, CNR, Via Del Fosso del Cavaliere 100, Rome 00133, Italy.
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Abstract
DNA topoisomerases are enzymes that catalyze changes in the torsional and flexural strain of DNA molecules. Earlier studies implicated these enzymes in a variety of processes in both prokaryotes and eukaryotes, including DNA replication, transcription, recombination, and chromosome segregation. Studies performed over the past 3 years have provided new insight into the roles of various topoisomerases in maintaining eukaryotic chromosome structure and facilitating the decatenation of daughter chromosomes at cell division. In addition, recent studies have demonstrated that the incorporation of ribonucleotides into DNA results in trapping of topoisomerase I (TOP1)–DNA covalent complexes during aborted ribonucleotide removal. Importantly, such trapped TOP1–DNA covalent complexes, formed either during ribonucleotide removal or as a consequence of drug action, activate several repair processes, including processes involving the recently described nuclear proteases SPARTAN and GCNA-1. A variety of new TOP1 inhibitors and formulations, including antibody–drug conjugates and PEGylated complexes, exert their anticancer effects by also trapping these TOP1–DNA covalent complexes. Here we review recent developments and identify further questions raised by these new findings.
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Affiliation(s)
- Mary-Ann Bjornsti
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, 35294-0019, USA
| | - Scott H Kaufmann
- Departments of Oncology and Molecular Pharmacolgy & Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
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5
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Daudee R, Gonen R, German U, Orion I, Alfassi ZB, Priel E. DNA Topoisomerase IB as a Potential Ionizing Radiation Exposure and Dose Biomarker. Radiat Res 2018; 189:652-660. [PMID: 29633912 DOI: 10.1667/rr14859.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In radiation exposure scenarios where physical dosimetry is absent or inefficient, dose estimation must rely on biological markers. A reliable biomarker is of utmost importance in correlating biological system changes with radiation exposure. Human DNA topoisomerase ІB (topo І) is a ubiquitous nuclear enzyme, which is involved in essential cellular processes, including transcription, DNA replication and DNA repair, and is the target of anti-cancer drugs. It has been shown that the cellular activity of this enzyme is significantly sensitive to various DNA lesions, including radiation-induced DNA damages. Therefore, we investigated the potential of topo I as a biomarker of radiation exposure and dose. We examined the effect of exposure of different human cells to beta, X-ray and gamma radiation on the cellular catalytic activity of topo I. The results demonstrate a significant reduction in the DNA relaxation activity of topo I after irradiation and the level of the reduction was correlated with radiation dose. In normal human peripheral blood lymphocytes, exposure for 3 h to an integral dose of 0.065 mGy from tritium reduced the enzyme activity to less than 25%. In MG-63 osteoblast-like cells and in human pulmonary fibroblast (HPF) cells exposed to gamma radiation from a 60Co source (up to 2 Gy) or to X rays (up to 2.8 Gy), a significant decrease in topo I catalytic activity was also observed. We observed that the enzyme-protein level was not altered but was partially posttranslational modified by ADP-ribosylation of the enzyme protein that is known to reduce topo I activity. The results of this study suggest that the decrease in the cellular topo I catalytic activity after low-dose exposure to different radiation types may be considered as a novel biomarker of ionizing radiation exposure and dose. For this purpose, a suitable ELISA-based method for large-scale analysis of radiation-induced topo I modification is under development.
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Affiliation(s)
- Rotem Daudee
- a The Shraga Segal Department of Immunology, Microbiology and Genetics Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.,b Department of Nuclear Engineering, Faculty of Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel.,c Nuclear Research Center, Negev, Beer Sheva, Israel
| | - Rafi Gonen
- a The Shraga Segal Department of Immunology, Microbiology and Genetics Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.,b Department of Nuclear Engineering, Faculty of Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel.,c Nuclear Research Center, Negev, Beer Sheva, Israel
| | - Uzi German
- c Nuclear Research Center, Negev, Beer Sheva, Israel
| | - Itzhak Orion
- b Department of Nuclear Engineering, Faculty of Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Zeev B Alfassi
- b Department of Nuclear Engineering, Faculty of Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Esther Priel
- a The Shraga Segal Department of Immunology, Microbiology and Genetics Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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Hekmat O, Munk S, Fogh L, Yadav R, Francavilla C, Horn H, Würtz SØ, Schrohl AS, Damsgaard B, Rømer MU, Belling KC, Jensen NF, Gromova I, Bekker-Jensen DB, Moreira JM, Jensen LJ, Gupta R, Lademann U, Brünner N, Olsen JV, Stenvang J. TIMP-1 increases expression and phosphorylation of proteins associated with drug resistance in breast cancer cells. J Proteome Res 2013; 12:4136-51. [PMID: 23909892 DOI: 10.1021/pr400457u] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Tissue inhibitor of metalloproteinase 1 (TIMP-1) is a protein with a potential biological role in drug resistance. To elucidate the unknown molecular mechanisms underlying the association between high TIMP-1 levels and increased chemotherapy resistance, we employed SILAC-based quantitative mass spectrometry to analyze global proteome and phosphoproteome differences of MCF-7 breast cancer cells expressing high or low levels of TIMP-1. In TIMP-1 high expressing cells, 312 proteins and 452 phosphorylation sites were up-regulated. Among these were the cancer drug targets topoisomerase 1, 2A, and 2B, which may explain the resistance phenotype to topoisomerase inhibitors that was observed in cells with high TIMP-1 levels. Pathway analysis showed an enrichment of proteins from functional categories such as apoptosis, cell cycle, DNA repair, transcription factors, drug targets and proteins associated with drug resistance or sensitivity, and drug transportation. The NetworKIN algorithm predicted the protein kinases CK2a, CDK1, PLK1, and ATM as likely candidates involved in the hyperphosphorylation of the topoisomerases. Up-regulation of protein and/or phosphorylation levels of topoisomerases in TIMP-1 high expressing cells may be part of the mechanisms by which TIMP-1 confers resistance to treatment with the widely used topoisomerase inhibitors in breast and colorectal cancer.
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Affiliation(s)
- Omid Hekmat
- Institute of Veterinary Disease Biology, Faculty of Health and Medical Sciences and Sino-Danish Breast Cancer Research Centre, University of Copenhagen, Dyrlægevej 88, 1., 1870 Frederiksberg C, Denmark
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7
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Bandyopadhyay K, Li P, Gjerset RA. CK2-mediated hyperphosphorylation of topoisomerase I targets serine 506, enhances topoisomerase I-DNA binding, and increases cellular camptothecin sensitivity. PLoS One 2012. [PMID: 23185622 PMCID: PMC3503890 DOI: 10.1371/journal.pone.0050427] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Topoisomerase I is the target for a potent class of chemotherapeutic drugs derived from the plant alkaloid camptothecin that includes irinotecan and topotecan. In this study we have identified a novel site of CK2-mediated topoisomerase I (topo I) phosphorylation at serine 506 (PS506) that is relevant to topo I function and to cellular responses to these topo I-targeted drugs. CK2 treatment induced hyperphosphorylation of recombinant topo I and expression of the PS506 epitope, and resulted in increased binding of topo I to supercoiled plasmid DNA. Hyperphosphorylated topo I was approximately three times more effective than the basal phosphorylated enzyme at relaxing plasmid supercoils but had similar DNA cleavage activity once bound to DNA. The PS506 epitope was expressed in cancer cell lines with elevated CK2 activity, hyperphosphorylated topo I, and increased sensitivity to camptothecin. In contrast, PS506 was not detected in normal cells or cancer cell lines with lower levels of CK2 activity. By experimentally manipulating CK2 activity in cancer cell lines, we demonstrate a cause and effect relationship between CK2 activity, PS506 expression, camptothecin-induced cellular DNA damage, and cellular camptothecin sensitivity. Our results show that the PS506 epitope is an indicator of dysregulated, hyperphosphorylated topo I in cancer cells, and may thus serve as a diagnostic or prognostic biomarker and predict tumor responsiveness to widely used topo I-targeted therapies.
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MESH Headings
- Antineoplastic Agents, Phytogenic/pharmacology
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Camptothecin/pharmacology
- Casein Kinase II/genetics
- Casein Kinase II/metabolism
- Cell Line, Tumor
- DNA Fragmentation/drug effects
- DNA Topoisomerases, Type I/genetics
- DNA Topoisomerases, Type I/metabolism
- DNA, Superhelical/metabolism
- Drug Resistance, Neoplasm/drug effects
- Drug Resistance, Neoplasm/genetics
- Epitopes
- Gene Expression Regulation, Neoplastic/drug effects
- Humans
- Phosphorylation/drug effects
- Plasmids
- Serine/genetics
- Serine/metabolism
- Topoisomerase I Inhibitors/pharmacology
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Affiliation(s)
- Keya Bandyopadhyay
- Torrey Pines Institute for Molecular Studies, San Diego, California, United States of America
| | - Pingchuan Li
- Torrey Pines Institute for Molecular Studies, San Diego, California, United States of America
| | - Ruth A. Gjerset
- Torrey Pines Institute for Molecular Studies, San Diego, California, United States of America
- * E-mail:
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8
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Su YF, Yang T, Huang H, Liu LF, Hwang J. Phosphorylation of Ubc9 by Cdk1 enhances SUMOylation activity. PLoS One 2012; 7:e34250. [PMID: 22509284 PMCID: PMC3317942 DOI: 10.1371/journal.pone.0034250] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 02/25/2012] [Indexed: 11/18/2022] Open
Abstract
Increasing evidence has pointed to an important role of SUMOylation in cell cycle regulation, especially for M phase. In the current studies, we have obtained evidence through in vitro studies that the master M phase regulator CDK1/cyclin B kinase phosphorylates the SUMOylation machinery component Ubc9, leading to its enhanced SUMOylation activity. First, we show that CDK1/cyclin B, but not many other cell cycle kinases such as CDK2/cyclin E, ERK1, ERK2, PKA and JNK2/SAPK1, specifically enhances SUMOylation activity. Second, CDK1/cyclin B phosphorylates the SUMOylation machinery component Ubc9, but not SAE1/SAE2 or SUMO1. Third, CDK1/cyclin B-phosphorylated Ubc9 exhibits increased SUMOylation activity and elevated accumulation of the Ubc9-SUMO1 thioester conjugate. Fourth, CDK1/cyclin B enhances SUMOylation activity through phosphorylation of Ubc9 at serine 71. These studies demonstrate for the first time that the cell cycle-specific kinase CDK1/cyclin B phosphorylates a SUMOylation machinery component to increase its overall SUMOylation activity, suggesting that SUMOylation is part of the cell cycle program orchestrated by CDK1 through Ubc9.
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Affiliation(s)
- Yee-Fun Su
- Molecular and Cell Biology Program, Taiwan International Graduate Program, Graduate Institute of Life Sciences, National Defense Medical Center and Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Tsunghan Yang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Hoting Huang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Leroy F. Liu
- Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey, United States of America
| | - Jaulang Hwang
- Molecular and Cell Biology Program, Taiwan International Graduate Program, Graduate Institute of Life Sciences, National Defense Medical Center and Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- * E-mail:
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9
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Identification of cyclohexanone derivatives that act as catalytic inhibitors of topoisomerase I: effects on tamoxifen-resistant MCF-7 cancer cells. Invest New Drugs 2011; 30:2103-12. [PMID: 22105790 PMCID: PMC3484282 DOI: 10.1007/s10637-011-9768-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 11/02/2011] [Indexed: 01/05/2023]
Abstract
Breast cancer is commonly treated with anti-estrogens or aromatase inhibitors, but resistant disease eventually develops and new therapies for such resistance are of great interest. We have previously isolated several tamoxifen-resistant variant sub-lines of the MCF-7 breast cancer cell line and provided evidence that they arose from expansion of pre-existing minor populations. We have searched for therapeutic agents that exhibit selective growth inhibition of the resistant lines and here investigate 2,6-bis(pyridin-3-ylmethylene)-cyclohexanone (RL90) and 2,6-bis(pyridin-4-ylmethylene)-cyclohexanone (RL91). We found that two of the tamoxifen-resistant sub-lines (TamR3 and TamC3) unexpectedly showed increased sensitivity to RL90 and RL91. We utilized growth inhibition assays, flow cytometry and immunoblotting to establish a mechanistic basis for their action. Treated sensitive cells showed S-phase selective DNA damage, as detected by histone H2AX phosphorylation. Cellular responses were similar to those induced by the topoisomerase I poison camptothecin. Although IC(50) values of camptothecin, RL90, RL91 were correlated, studies with purified mammalian topoisomerase I suggested that RL90 and RL91 differed from camptothecin by acting as catalytic topoisomerase I inhibitors. These drugs provide a platform for the further development of DNA damaging drugs that have selective effects on tamoxifen resistant breast cancer cells. The results also raise the question of whether clinical topoisomerase I poisons such as irinotecan and topotecan might be active in the treatment of some types of tamoxifen-resistant cancer.
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10
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Bandyopadhyay K, Gjerset RA. Protein kinase CK2 is a central regulator of topoisomerase I hyperphosphorylation and camptothecin sensitivity in cancer cell lines. Biochemistry 2011; 50:704-14. [PMID: 21182307 DOI: 10.1021/bi101110e] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Topoisomerase I (topo I) is required to unwind DNA during synthesis and provides the unique target for camptothecin-derived chemotherapeutic agents, including Irinotecan and Topotecan. While these agents are highly effective anticancer agents, some tumors do not respond due to intrinsic or acquired resistance, a process that remains poorly understood. Because of treatment toxicity, there is interest in identifying cellular factors that regulate tumor sensitivity and might serve as predictive biomarkers of therapy sensitivity. Here we identify the serine kinase, protein kinase CK2, as a central regulator of topo I hyperphosphorylation and activity and cellular sensitivity to camptothecin. In nine cancer cell lines and three normal tissue-derived cell lines we observe a consistent correlation between CK2 levels and camptothecin responsiveness. Two other topo I-targeted serine kinases, protein kinase C and cyclin-dependent kinase 1, do not show this correlation. Camptothecin-sensitive cancer cell lines display high CK2 activity, hyperphosphorylation of topo I, elevated topo I activity, and elevated phosphorylation-dependent complex formation between topo I and p14ARF, a topo I activator. Camptothecin-resistant cancer cell lines and normal cell lines display lower CK2 activity, lower topo I phosphorylation, lower topo I activity, and undetectable topo I/p14ARF complex formation. Experimental inhibition or activation of CK2 demonstrates that CK2 is necessary and sufficient for regulating these topo I properties and altering cellular responses to camptothecin. The results establish a cause and effect relationship between CK2 activity and camptothecin sensitivity and suggest that CK2, topo I phosphorylation, or topo I/p14ARF complex formation could provide biomarkers of therapy-responsive tumors.
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Affiliation(s)
- Keya Bandyopadhyay
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, California 92121, United States
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11
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Vassallo O, Castelli S, D'Annessa I, della Rocca BM, Stella L, Knudsen BR, Desideri A. Evidences of a natively unfolded state for the human topoisomerase IB N-terminal domain. Amino Acids 2010; 41:945-53. [PMID: 21046176 DOI: 10.1007/s00726-010-0794-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 10/20/2010] [Indexed: 09/29/2022]
Abstract
The N-terminal domain of human topoisomerase IB has been expressed, purified and characterized by spectroscopic techniques. CD spectra as a function of concentration and pH indicate that the domain does not possess any defined secondary structure. The protein is probably in a natively unfolded state since its denaturation curve is indicative of a non-cooperative transition. Evidence of a partially folded structure comes from the fluorescence spectrum of ANS, whose intensity increases in presence of the domain. Indication of a partial structural arrangement of the domain comes also from the endogenous fluorescence of tryptophans that is centred at 350 nm in the native and shifts to 354 nm in the fully denaturated protein. Interestingly despite the poor structural degree, as also confirmed by a predictive approach, the domain efficiently binds DNA, suggesting that the absence of a defined 3D structure has a functional meaning that permits the domain to be available for the interaction with different molecular partners.
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Affiliation(s)
- Oscar Vassallo
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica, 00133, Rome, Italy
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12
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Pham MH, Kondapalli N, Reckord CL, Foglesong PD. Interleukin-2 induces the activities of DNA topoisomerase I and DNA topoisomerase II in HuT 78 cells. Biochem Biophys Res Commun 2009; 390:577-80. [PMID: 19818738 PMCID: PMC2789651 DOI: 10.1016/j.bbrc.2009.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 10/01/2009] [Indexed: 11/21/2022]
Abstract
The induction by interleukin-2 of DNA topoisomerase I and DNA topoisomerase II activities in the human T cell line HuT 78 was investigated. HuT 78 cells were treated with 1000 U of interleukin-2/ml, and extracts of the HuT 78 nuclei were prepared over a 24h period. The extracts were assayed quantitatively for the activities of DNA topoisomerase I and DNA topoisomerase II. Three concomitant, transient increases of 3- to 11-fold in the specific activities of both DNA topoisomerase I and DNA topoisomerase II were observed following treatment with IL-2 at 0.5, 4, and 10h after treatment with interleukin-2. The specific activities of both enzymes returned to base-line values after each of these transient increases. These results reveal that the activities of DNA topoisomerase I and DNA topoisomerase II are highly regulated in HuT 78 cells upon treatment with IL-2.
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Affiliation(s)
- Minh-Hieu Pham
- Department of Biology, UPO #311, University of the Incarnate Word, 4301 Broadway, San Antonio, TX 78209-6318
| | - Navya Kondapalli
- Department of Biology, UPO #311, University of the Incarnate Word, 4301 Broadway, San Antonio, TX 78209-6318
| | - Calvin L. Reckord
- Biology Department, Rutgers University, 311 North Fifth Street, Camden, NJ 08102-1405
| | - P. David Foglesong
- Department of Biology, UPO #311, University of the Incarnate Word, 4301 Broadway, San Antonio, TX 78209-6318
- Biology Department, Rutgers University, 311 North Fifth Street, Camden, NJ 08102-1405
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13
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de la Loza MCD, Wellinger RE. A novel approach for organelle-specific DNA damage targeting reveals different susceptibility of mitochondrial DNA to the anticancer drugs camptothecin and topotecan. Nucleic Acids Res 2009; 37:e26. [PMID: 19151088 PMCID: PMC2651790 DOI: 10.1093/nar/gkn1087] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
DNA is susceptible of being damaged by chemicals, UV light or gamma irradiation. Nuclear DNA damage invokes both a checkpoint and a repair response. By contrast, little is known about the cellular response to mitochondrial DNA damage. We designed an experimental system that allows organelle-specific DNA damage targeting in Saccharomyces cerevisiae. DNA damage is mediated by a toxic topoisomerase I allele which leads to the formation of persistent DNA single-strand breaks. We show that organelle-specific targeting of a toxic topoisomerase I to either the nucleus or mitochondria leads to nuclear DNA damage and cell death or to loss of mitochondrial DNA and formation of respiration-deficient ‘petite’ cells, respectively. In wild-type cells, toxic topoisomerase I–DNA intermediates are formed as a consequence of topoisomerase I interaction with camptothecin-based anticancer drugs. We reasoned that targeting of topoisomerase I to the mitochondria of top1Δ cells should lead to petite formation in the presence of camptothecin. Interestingly, camptothecin failed to generate petite; however, its derivative topotecan accumulates in mitochondria and induces petite formation. Our findings demonstrate that drug modifications can lead to organelle-specific DNA damage and thus opens new perspectives on the role of mitochondrial DNA-damage in cancer treatment.
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Affiliation(s)
- M C Díaz de la Loza
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla - CSIC, Avda, Américo Vespucio s/n, 41092, Sevilla, Spain
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