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Xu Z, Wei J, Abid A, Liu Z, Wu Y, Gu J, Ma D, Zheng M. Formation and toxicity contribution of chlorinated and dechlorinated halobenzoquinones from dichlorophenols after ozonation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 914:169860. [PMID: 38199341 DOI: 10.1016/j.scitotenv.2023.169860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/23/2023] [Accepted: 12/31/2023] [Indexed: 01/12/2024]
Abstract
Halobenzoquinones (HBQs) are a class of disinfection byproducts with high cytotoxicity and potential carcinogenicity, which have been widely detected in chlorination of drinking water and swimming pool water. However, to date, the formation of HBQs upon ozonation and the HBQ precursors have been overlooked. This study investigated the formation of chlorinated and dechlorinated HBQs from six dichlorophenol (DCP) isomers. The monomeric and dimeric HBQs were identified in all the ozonation effluents, exhibiting 1-100 times higher toxicity levels than their precursors. The sum of detected HBQs intensity had a satisfactory linear relation with the maximum toxic unit (R2 = 0.9657), indicating the primary toxicity contribution to the increased overall toxicity of effluents. Based on density functional theory calculations, when ozone attacks the para carbon to the hydroxyl group of 2,3-DCP, the probability of producing chlorinated HBQs is 80.41 %, indicating that the para carbon attack mainly resulted in the formation of monomeric HBQs. 2,3-dichlorophenoxy radicals were successfully detected in ozonated 2,3-DCP effluent through electron paramagnetic resonance and further validated using theoretical calculation, revealing the formation pathway of dimeric HBQs. The results indicate that chlorinated phenols, regardless of the positions of chlorine substitution, can potentially serve as precursors for both chlorinated and dechlorinated HBQs formation during ozonation.
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Affiliation(s)
- Zhourui Xu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Jianjian Wei
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Aroob Abid
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Zirui Liu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Yasen Wu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Jia Gu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Dehua Ma
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China.
| | - Min Zheng
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
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Jiang X, Fielding LA, Davis H, Carroll W, Lisic EC, Deweese JE. Inhibition of Topoisomerases by Metal Thiosemicarbazone Complexes. Int J Mol Sci 2023; 24:12010. [PMID: 37569386 PMCID: PMC10419228 DOI: 10.3390/ijms241512010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/20/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
Topoisomerases, common targets for anti-cancer therapeutics, are crucial enzymes for DNA replication, transcription, and many other aspects of DNA metabolism. The potential anti-cancer effects of thiosemicarbazones (TSC) and metal-TSC complexes have been demonstrated to target several biological processes, including DNA metabolism. Human topoisomerases were discovered among the molecular targets for TSCs, and metal-chelated TSCs specifically displayed significant inhibition of topoisomerase II. The processes by which metal-TSCs or TSCs inhibit topoisomerases are still being studied. In this brief review, we summarize the TSCs and metal-TSCs that inhibit various types of human topoisomerases, and we note some of the key unanswered questions regarding this interesting class of diverse compounds.
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Affiliation(s)
- Xiaohua Jiang
- Department of Chemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Lauren A. Fielding
- Department of Biological, Physical and Human Sciences, Freed Hardeman University, Henderson, TN 38340, USA
| | - Hunter Davis
- Department of Chemistry, Tennessee Tech University, Cookeville, TN 38505, USA
| | - William Carroll
- Department of Chemistry, Tennessee Tech University, Cookeville, TN 38505, USA
| | - Edward C. Lisic
- Department of Chemistry, Tennessee Tech University, Cookeville, TN 38505, USA
| | - Joseph E. Deweese
- Department of Biological, Physical and Human Sciences, Freed Hardeman University, Henderson, TN 38340, USA
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
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Lungu CN, Mangalagiu V, Mangalagiu II, Mehedinti MC. Benzoquinoline Chemical Space: A Helpful Approach in Antibacterial and Anticancer Drug Design. Molecules 2023; 28:molecules28031069. [PMID: 36770739 PMCID: PMC9921191 DOI: 10.3390/molecules28031069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/09/2023] [Accepted: 01/16/2023] [Indexed: 01/24/2023] Open
Abstract
Benzoquinolines are used in many drug design projects as starting molecules subject to derivatization. This computational study aims to characterize e benzoquinone drug space to ease future drug design processes based on these molecules. The drug space is composed of all benzoquinones, which are active on topoisomerase II and ATP synthase. Topological, chemical, and bioactivity spaces are explored using computational methodologies based on virtual screening and scaffold hopping and molecular docking, respectively. Topological space is a geometrical space in which the elements composing it can be defined as a set of neighbors (which satisfy a particular axiom). In such space, a chemical space can be defined as the property space spanned by all possible molecules and chemical compounds adhering to a given set of construction principles and boundary conditions. In this chemical space, the potentially pharmacologically active molecules form the bioactivity space. Results show a poly-morphological chemical space that suggests distinct characteristics. The chemical space is correlated with properties such as steric energy, the number of hydrogen bonds, the presence of halogen atoms, and membrane permeability-related properties. Lastly, novel chemical compounds (such as oxadiazole methybenzamide and floro methylcyclohexane diene) with drug-like potential, active on TOPO II and ATP synthase have been identified.
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Affiliation(s)
- Claudiu N. Lungu
- Department of Surgery, Emergency Country Clinical Hospital, 800010 Galati, Romania
- Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania
- Department of Morphological and Functional Science, University of Medicine and Pharmacy, Dunarea de Jos, 800017 Galati, Romania
- Correspondence: (C.N.L.); (I.I.M.)
| | - Violeta Mangalagiu
- Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania
- Faculty of Food Engineering, Stefan cel Mare University of Suceava, 13 Universitatii Str., 720229 Suceava, Romania
| | - Ionel I. Mangalagiu
- Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania
- Institute of Interdisciplinary Research-CERNESIM Centre, Alexandru Ioan Cuza University of Iasi, 11 Carol I, 700506 Iasi, Romania
- Correspondence: (C.N.L.); (I.I.M.)
| | - Mihaela C. Mehedinti
- Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania
- Department of Morphological and Functional Science, University of Medicine and Pharmacy, Dunarea de Jos, 800017 Galati, Romania
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Holmes TH, Winn LM. DNA damage, DNA repair gene expression, and topoisomerase IIα activity in CD-1 mice following in utero benzene exposure. Toxicol Lett 2022; 368:47-55. [PMID: 35963423 DOI: 10.1016/j.toxlet.2022.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/16/2022] [Accepted: 08/08/2022] [Indexed: 11/19/2022]
Abstract
Benzene is an environmental toxicant and known human carcinogen. Recent epidemiological studies show a relationship between exposure to benzene in pregnant women and increased incidence of childhood leukemias. Studies in murine models demonstrate a relationship between carcinogenicity and in utero benzene exposure which was sex dependent, thus the cellular mechanisms of benzene toxicity by sex require further studies. A hypothesized mechanism of benzene-induced in utero carcinogenicity is through increased DNA damage and reduced fetal DNA repair capacity. This includes the potential inhibition of topoisomerase IIα (topo IIα), in part, to generate double stranded DNA (dsDNA) breaks and induction of error-prone DNA repair. Using a mouse model of transplacental benzene carcinogenicity, gestational day (GD) 14 fetal livers were harvested 2, 6, and 24 h following maternal exposure to 200 mg/kg benzene and used to assess DNA damage, DNA repair gene expression and topo IIα activity. DNA damage, measured by levels of modified histone H2AX (γH2AX), is significantly increased in benzene exposed pups, with sex-dependent significance seen only in female pups. Comet assay results confirmed that benzene exposure in utero induces dsDNA damage in the GD14 fetal liver. Genes involved in DNA repair were assessed, and DNA repair gene expression changes were observed after 24 h in genes related to nucleotide excision repair, homologous recombination, and non-homologous end-joining. There were no significant differences in topo IIα activity in GD14 fetal livers at any timepoint, or between sexes. Overall, this study shows that 200 mg/kg benzene exposure induces dsDNA damage and alters fetal DNA repair gene expression in utero, without perturbing fetal topo IIα in CD-1 mice.
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Affiliation(s)
- Trent H Holmes
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Louise M Winn
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada; School of Environmental Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada.
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Zhang W, Gou P, Dupret JM, Chomienne C, Rodrigues-Lima F. Etoposide, an anticancer drug involved in therapy-related secondary leukemia: Enzymes at play. Transl Oncol 2021; 14:101169. [PMID: 34243013 PMCID: PMC8273223 DOI: 10.1016/j.tranon.2021.101169] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 01/13/2023] Open
Abstract
Etoposide is a semi-synthetic glycoside derivative of podophyllotoxin, also known as VP-16. It is a widely used anticancer medicine in clinics. Unfortunately, high doses or long-term etoposide treatment can induce therapy-related leukemia. The mechanism by which etoposide induces secondary hematopoietic malignancies is still unclear. In this article, we review the potential mechanisms of etoposide induced therapy-related leukemia. Etoposide related leukemogenesis is known to depend on reactive oxidative metabolites of etoposide, notably etoposide quinone, which interacts with cellular proteins such as topoisomerases II (TOP2), CREB-binding protein (CREBBP), and T-Cell Protein Tyrosine Phosphatase (TCPTP). CYP3A4 and CYP3A5 metabolize etoposide to etoposide catechol, which readily oxidizes to etoposide quinone. As a poison of TOP2 enzymes, etoposide and its metabolites induce DNA double-stranded breaks (DSB), and the accumulation of DSB triggers cell apoptosis. If the cell survives, the DSB gives rise to the likelihood of faulty DNA repair events. The gene translocation could occur in mixed-lineage leukemia (MLL) gene, which is well-known in leukemogenesis. Recently, studies have revealed that etoposide metabolites, especially etoposide quinone, can covalently bind to cysteines residues of CREBBP and TCPTP enzymes, . This leads to enzyme inhibition and further affects histone acetylation and phosphorylation of the JAK-STAT pathway, thus putatively altering the proliferation and differentiation of hematopoietic stem cells (HSC). In brief, current studies suggest that etoposide and its metabolites contribute to etoposide therapy-related leukemia through TOP2 mediated DSB and impairs specific enzyme activity, such as CREBBP and TCPTP.
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Affiliation(s)
- Wenchao Zhang
- Université de Paris, BFA, UMR 8251, CNRS, Paris F-75013, France.
| | - Panhong Gou
- Inserm UMR-S1131, Université de Paris, IRSL, Hôpital Saint-Louis, Paris, France
| | | | - Christine Chomienne
- Inserm UMR-S1131, Université de Paris, IRSL, Hôpital Saint-Louis, Paris, France; Service de Biologie Cellulaire, Assistance Publique des Hôpitaux de Paris (AP-HP), Hôpital Saint Louis, Paris, France
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Kiselev VD, Kolesnikova AO, Shulyatiev AA, Dinikaev IF, Kornilov DA. Sharp difference in the rate of formation and stability of the Diels–Alder reaction adducts with 2,3‐dicyano‐1,4‐benzoquinone and N‐phenylimide‐1,4‐benzoquinone‐2,3‐dicarboxylic acid. INT J CHEM KINET 2021. [DOI: 10.1002/kin.21534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Vladimir D. Kiselev
- The A.M. Butlerov Chemical Institute Kazan Federal University Kazan Russian Federation
| | | | - Alexey A. Shulyatiev
- The A.M. Butlerov Chemical Institute Kazan Federal University Kazan Russian Federation
| | - Ildar F. Dinikaev
- The A.M. Butlerov Chemical Institute Kazan Federal University Kazan Russian Federation
| | - Dmitry A. Kornilov
- The A.M. Butlerov Chemical Institute Kazan Federal University Kazan Russian Federation
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Berthelet J, Michail C, Bui LC, Le Coadou L, Sirri V, Wang L, Dulphy N, Dupret JM, Chomienne C, Guidez F, Rodrigues-Lima F. The benzene hematotoxic and reactive metabolite 1,4-benzoquinone impairs the activity of the histone methyltransferase SETD2 and causes aberrant H3K36 trimethylation (H3K36me3). Mol Pharmacol 2021; 100:283-294. [PMID: 34266924 DOI: 10.1124/molpharm.121.000303] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/28/2021] [Indexed: 11/22/2022] Open
Abstract
Human SETD2 is the unique histone methyltransferase that generates H3K36me3, an epigenetic mark that plays a key role in normal hematopoiesis. Interestingly, recurrent-inactivating mutations of SETD2 and aberrant H3K36 trimethylation (H3K36me3) are increasingly reported to be involved in hematopoietic malignancies. Benzene (BZ) is an ubiquitous environmental pollutant and carcinogen that causes leukemia. The leukemogenic properties of BZ depend on its biotransformation in the bone marrow into oxidative metabolites in particular 1,4-benzoquinone (BQ). This hematotoxic metabolite can form DNA and protein adducts that result in the damage and the alteration of cellular processes. Recent studies suggest that BZ-depend leukemogenesis could depend on epigenetic perturbations notably aberrant histone methylation. We investigated whether H3K36 trimethylation by SETD2 could be impacted by BZ and its hematotoxic metabolites. Herein, we show that BQ, the major leukemogenic metabolite of BZ, inhibits irreversibly the human histone methyltransferase SETD2 resulting in decreased H3K36 trimethylation (H3K36me3). Our mechanistic studies further indicate that the BQ-dependent inactivation of SETD2 is due to covalent binding of BQ to reactive Zn-finger cysteines within the catalytic domain of the enzyme. The formation of these quinoprotein adducts results in loss of enzyme activity and protein cross-links/oligomers. Experiments conducted in hematopoietic cells confirm that exposure to BQ results in the formation of SETD2 cross-links/oligomers and concomitant loss of H3K36me3 in cells. Taken together, our data indicate that BQ, a major hematotoxic metabolite of BZ could contribute to BZ-dependent leukemogenesis by perturbing the functions of SETD2, an histone lysine methyltransferase of hematopoietic relevance. Significance Statement Benzoquinone is a major leukemogenic metabolite of benzene. Dysregulation of histone methyltransferase is involved in hematopoietic malignancies. We found that benzoquinone irreversibly impairs SETD2, a histone H3K36 methyltransferase that plays a key role in hematopoiesis. Benzoquinone forms covalent adducts on Zn-finger cysteines within the catalytic site leading to loss of activity, protein cross-links/oligomers and concomitant decrease of H3K36me3 histone mark. Our data provide evidence that a leukemogenic metabolite of benzene can impair a key epigenetic enzyme.
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Affiliation(s)
| | | | | | | | | | - Li Wang
- The First Affiliated Hospital of Chongqing Medical University, China
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Vann KR, Oviatt AA, Osheroff N. Topoisomerase II Poisons: Converting Essential Enzymes into Molecular Scissors. Biochemistry 2021; 60:1630-1641. [PMID: 34008964 PMCID: PMC8209676 DOI: 10.1021/acs.biochem.1c00240] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The extensive length, compaction, and interwound nature of DNA, together with its controlled and restricted movement in eukaryotic cells, create a number of topological issues that profoundly affect all of the functions of the genetic material. Topoisomerases are essential enzymes that modulate the topological structure of the double helix, including the regulation of DNA under- and overwinding and the removal of tangles and knots from the genome. Type II topoisomerases alter DNA topology by generating a transient double-stranded break in one DNA segment and allowing another segment to pass through the DNA gate. These enzymes are involved in a number of critical nuclear processes in eukaryotic cells, such as DNA replication, transcription, and recombination, and are required for proper chromosome structure and segregation. However, because type II topoisomerases generate double-stranded breaks in the genetic material, they also are intrinsically dangerous enzymes that have the capacity to fragment the genome. As a result of this dualistic nature, type II topoisomerases are the targets for a number of widely prescribed anticancer drugs. This article will describe the structure and catalytic mechanism of eukaryotic type II topoisomerases and will go on to discuss the actions of topoisomerase II poisons, which are compounds that stabilize DNA breaks generated by the type II enzyme and convert these essential enzymes into "molecular scissors." Topoisomerase II poisons represent a broad range of structural classes and include anticancer drugs, dietary components, and environmental chemicals.
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Affiliation(s)
- Kendra R Vann
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Alexandria A Oviatt
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Neil Osheroff
- Departments of Biochemistry and Medicine (Hematology/Oncology), Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- VA Tennessee Valley Healthcare System, Nashville, Tennessee 37212, United States
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Chow PW, Abd Hamid Z, Mathialagan RD, Rajab NF, Shuib S, Sulong S. Clastogenicity and Aneugenicity of 1,4-Benzoquinone in Different Lineages of Mouse Hematopoietic Stem/Progenitor Cells. TOXICS 2021; 9:toxics9050107. [PMID: 34065823 PMCID: PMC8150741 DOI: 10.3390/toxics9050107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 05/03/2021] [Accepted: 05/07/2021] [Indexed: 11/16/2022]
Abstract
Previous reports on hematotoxicity and leukemogenicity related to benzene exposure highlighted its adverse effects on hematopoiesis. Despite the reported findings, studies concerning the mechanism of benzene affecting chromosomal integrity in lineage-committed hematopoietic stem/progenitor cells (HSPCs) remain unclear. Here, we studied the clastogenicity and aneugenicity of benzene in lineage-committed HSPCs via karyotyping. Isolated mouse bone marrow cells (MBMCs) were exposed to the benzene metabolite 1,4-benzoquinone (1,4-BQ) at 1.25, 2.5, 5, 7, and 12 μM for 24 h, followed by karyotyping. Then, the chromosomal aberration (CA) in 1,4-BQ-exposed hematopoietic progenitor cells (HPCs) comprising myeloid, Pre-B lymphoid, and erythroid lineages were evaluated following colony-forming cell (CFC) assay. Percentage of CA, predominantly via Robertsonian translocation (Rb), was increased significantly (p < 0.05) in MBMCs and all progenitors at all concentrations. As a comparison, Pre-B lymphoid progenitor demonstrated a significantly higher percentage of CA (p < 0.05) than erythroid progenitor at 1.25, 2.5, and 7 μM as well as a significantly higher percentage (p < 0.05) than myeloid progenitor at 7 μM of 1,4-BQ. In conclusion, 1,4-BQ induced CA, particularly via Rb in both MBMCs and HPCs, notably via a lineage-dependent response. The role of lineage specificity in governing the clastogenicity and aneugenicity of 1,4-BQ deserves further investigation.
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Affiliation(s)
- Paik Wah Chow
- Biomedical Science Programme and Center for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia; (P.W.C.); (R.D.M.)
| | - Zariyantey Abd Hamid
- Biomedical Science Programme and Center for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia; (P.W.C.); (R.D.M.)
- Correspondence: ; Tel.: +60-3-9289-7196
| | - Ramya Dewi Mathialagan
- Biomedical Science Programme and Center for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia; (P.W.C.); (R.D.M.)
| | - Nor Fadilah Rajab
- Biomedical Science Programme and Center for Healthy Ageing & Wellness, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia;
| | - Salwati Shuib
- Department of Pathology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia;
| | - Sarina Sulong
- Human Genome Center, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kelantan 16150, Malaysia;
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Abstract
1,2-Naphthoquinone, a secondary metabolite of naphthalene, is an environmental pollutant found in diesel exhaust particles that displays cytotoxic and genotoxic properties. Because many quinones have been shown to act as topoisomerase II poisons, the effects of this compound on DNA cleavage mediated by human topoisomerase IIα and IIβ were examined. The compound increased the levels of double-stranded DNA breaks generated by both enzyme isoforms and did so better than a series of naphthoquinone derivatives. Furthermore, 1,2-naphthoquinone was a more efficacious poison against topoisomerase IIα than IIβ. Topoisomerase II poisons can be classified as interfacial (which interact noncovalently at the enzyme-DNA interface and increase DNA cleavage by blocking ligation) or covalent (which adduct the protein and increase DNA cleavage by closing the N-terminal gate of the enzyme). Therefore, experiments were performed to determine the mechanistic basis for the actions of 1,2-naphthoquinone. In contrast to results with etoposide (an interfacial poison), the activity of 1,2-naphthoquinone against topoisomerase IIα was abrogated in the presence of sulfhydryl and reducing agents. Moreover, the compound inhibited cleavage activity when incubated with the enzyme prior to the addition of DNA and induced virtually no cleavage with the catalytic core of the enzyme. It also induced stable covalent topoisomerase IIα-DNA cleavage complexes and was a partial inhibitor of DNA ligation. Findings were also consistent with 1,2-naphthoquinone acting as a covalent poison of topoisomerase IIβ; however, mechanistic studies with this isoform were less conclusive. Whereas the activity of 1,2-naphthoquinone was blocked in the presence of a sulfhydryl reagent, it was much less sensitive to the presence of a reducing agent. Furthermore, the reduced form of 1,2-naphthoquinone, 1,2-dihydroxynaphthalene, displayed high activity against the β isoform. Taken together, results suggest that 1,2-naphthoquinone increases topoisomerase II-mediated double-stranded DNA scission (at least in part) by acting as a covalent poison of the human type II enzymes.
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Affiliation(s)
- Jessica A. Collins
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Neil Osheroff
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Department of Medicine (Hematology/Oncology), Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- VA Tennessee Valley Healthcare System, Nashville, Tennessee 37212, United States
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Antoci V, Oniciuc L, Amariucai-Mantu D, Moldoveanu C, Mangalagiu V, Amarandei AM, Lungu CN, Dunca S, Mangalagiu II, Zbancioc G. Benzoquinoline Derivatives: A Straightforward and Efficient Route to Antibacterial and Antifungal Agents. Pharmaceuticals (Basel) 2021; 14:ph14040335. [PMID: 33917439 PMCID: PMC8067460 DOI: 10.3390/ph14040335] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 03/26/2021] [Accepted: 04/02/2021] [Indexed: 02/07/2023] Open
Abstract
We report here the design, synthesis, experimental and in silico evaluation of the antibacterial and antifungal activity of some new benzo[f]quinoline derivatives. Two classes of benzo[f]quinolinium derivatives—(benzo[f]quinolinium salts (BQS) and pyrrolobenzo[f]quinolinium cycloadducts (PBQC)—were designed and obtained in two steps via a direct and facile procedure: quaternization followed by a cycloaddition reaction. The synthesized compounds were characterized by elemental and spectral analysis (FT-IR, 1H-NMR, 13C-NMR). The antimicrobial assay reveals that the BQS salts have an excellent quasi-nonselective antifungal activity against the fungus Candida albicans (some of them higher that the control drug nystatin) and very good antibacterial activity against the Gram positive bacterium Staphylococcus aureus. The PBQC compounds are inactive. Analysis of the biological data reveals interesting SAR correlations in the benzo[f]quinolinium series of compounds. The in silico studies furnished important data concerning the pharmacodynamics, pharmacokinetics and ADMET parameters of the BQS salts. Studies of the interaction of each BQS salt 3a–o with ATP synthase in the formed complex, reveal that salts 3j, 3i, and 3n have the best fit in a complex with ATP synthase. Study of the interaction of each BQS salt 3a-o with TOPO II in the formed complex reveals that salts 3j and 3n have the best-fit in complex with TOPO II. The in silico ADMET studies reveal that the BQS salts have excellent drug-like properties, including a low toxicity profile. Overall, the experimental and in silico studies indicate that compounds 3e and 3f (from the aliphatic series), respectively, and 3i, 3j and 3n (from the aromatic series), are promising leading drug candidates.
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Affiliation(s)
- Vasilichia Antoci
- Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania; (V.A.); (L.O.); (D.A.-M.); (C.M.); (I.I.M.)
| | - Liliana Oniciuc
- Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania; (V.A.); (L.O.); (D.A.-M.); (C.M.); (I.I.M.)
| | - Dorina Amariucai-Mantu
- Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania; (V.A.); (L.O.); (D.A.-M.); (C.M.); (I.I.M.)
| | - Costel Moldoveanu
- Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania; (V.A.); (L.O.); (D.A.-M.); (C.M.); (I.I.M.)
| | - Violeta Mangalagiu
- Institute of Interdisciplinary Research—CERNESIM Centre, Alexandru Ioan Cuza University of Iasi, 11 Carol I, 700506 Iasi, Romania;
| | | | - Claudiu N. Lungu
- Department of Surgery, Emergency Clinical Hospital, 810325 Braila, Romania
- Correspondence: (C.N.L.); (S.D.); (G.Z.)
| | - Simona Dunca
- Faculty of Biology, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania;
- Correspondence: (C.N.L.); (S.D.); (G.Z.)
| | - Ionel I. Mangalagiu
- Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania; (V.A.); (L.O.); (D.A.-M.); (C.M.); (I.I.M.)
- Institute of Interdisciplinary Research—CERNESIM Centre, Alexandru Ioan Cuza University of Iasi, 11 Carol I, 700506 Iasi, Romania;
| | - Gheorghita Zbancioc
- Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, 11 Carol 1st Bvd, 700506 Iasi, Romania; (V.A.); (L.O.); (D.A.-M.); (C.M.); (I.I.M.)
- Correspondence: (C.N.L.); (S.D.); (G.Z.)
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12
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Horn CM, Aucamp J, Smit FJ, Seldon R, Jordaan A, Warner DF, N’Da DD. Synthesis and in vitro antimycobacterial and antileishmanial activities of hydroquinone-triazole hybrids. Med Chem Res 2020. [DOI: 10.1007/s00044-020-02553-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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13
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Kolesnikova AO, Kornilov DA, Gubaidullin AT, Kiselev VD. Study of all stages of the Diels–Alder reaction of cyclopentadiene with 2,3‐dicyano‐1,4‐benzoquinone and monoadducts: Kinetics, thermochemistry, and high pressure effect. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Dmitry A. Kornilov
- The A. M. Butlerov Chemical InstituteKazan Federal University Kazan 420008 Russian Federation
| | - Aidar T. Gubaidullin
- The A. E. Arbuzov Institute of Organic and Physical ChemistryFRC Kazan Scientific CenterRussian Academy of Sciences Kazan 420088 Russian Federation
| | - Vladimir D. Kiselev
- The A. M. Butlerov Chemical InstituteKazan Federal University Kazan 420008 Russian Federation
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14
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Luijten M, Ball NS, Dearfield KL, Gollapudi BB, Johnson GE, Madia F, Peel L, Pfuhler S, Settivari RS, ter Burg W, White PA, van Benthem J. Utility of a next generation framework for assessment of genomic damage: A case study using the industrial chemical benzene. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:94-113. [PMID: 31709603 PMCID: PMC6972600 DOI: 10.1002/em.22346] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/31/2019] [Accepted: 11/06/2019] [Indexed: 05/22/2023]
Abstract
We recently published a next generation framework for assessing the risk of genomic damage via exposure to chemical substances. The framework entails a systematic approach with the aim to quantify risk levels for substances that induce genomic damage contributing to human adverse health outcomes. Here, we evaluated the utility of the framework for assessing the risk for industrial chemicals, using the case of benzene. Benzene is a well-studied substance that is generally considered a genotoxic carcinogen and is known to cause leukemia. The case study limits its focus on occupational and general population health as it relates to benzene exposure. Using the framework as guidance, available data on benzene considered relevant for assessment of genetic damage were collected. Based on these data, we were able to conduct quantitative analyses for relevant data sets to estimate acceptable exposure levels and to characterize the risk of genetic damage. Key observations include the need for robust exposure assessments, the importance of information on toxicokinetic properties, and the benefits of cheminformatics. The framework points to the need for further improvement on understanding of the mechanism(s) of action involved, which would also provide support for the use of targeted tests rather than a prescribed set of assays. Overall, this case study demonstrates the utility of the next generation framework to quantitatively model human risk on the basis of genetic damage, thereby enabling a new, innovative risk assessment concept. Environ. Mol. Mutagen. 61:94-113, 2020. © 2019 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.
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Affiliation(s)
- Mirjam Luijten
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | | | | | | | - George E. Johnson
- Swansea University Medical School, Swansea UniversitySwanseaUnited Kingdom
| | - Federica Madia
- European Commission, Joint Research Centre (JRC)IspraItaly
| | - Lauren Peel
- Health and Environmental Sciences InstituteWashingtonDistrict of Columbia
| | | | | | - Wouter ter Burg
- Centre for Safety of Substances and ProductsNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Paul A. White
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
| | - Jan van Benthem
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
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15
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Dewi R, Hamid ZA, Rajab NF, Shuib S, Razak SA. Genetic, epigenetic, and lineage-directed mechanisms in benzene-induced malignancies and hematotoxicity targeting hematopoietic stem cells niche. Hum Exp Toxicol 2019; 39:577-595. [PMID: 31884827 DOI: 10.1177/0960327119895570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Benzene is a known hematotoxic and leukemogenic agent with hematopoietic stem cells (HSCs) niche being the potential target. Occupational and environmental exposure to benzene has been linked to the incidences of hematological disorders and malignancies. Previous studies have shown that benzene may act via multiple modes of action targeting HSCs niche, which include induction of chromosomal and micro RNA aberrations, leading to genetic and epigenetic modification of stem cells and probable carcinogenesis. However, understanding the mechanism linking benzene to the HSCs niche dysregulation is challenging due to complexity of its microenvironment. The niche is known to comprise of cell populations accounted for HSCs and their committed progenitors of lymphoid, erythroid, and myeloid lineages. Thus, it is fundamental to address novel approaches via lineage-directed strategy to elucidate precise mechanism involved in benzene-induced toxicity targeting HSCs and progenitors of different lineages. Here, we review the key genetic and epigenetic factors that mediate hematotoxicological effects by benzene and its metabolites in targeting HSCs niche. Overall, the use of combined genetic, epigenetic, and lineage-directed strategies targeting the HSCs niche is fundamental to uncover the key mechanisms in benzene-induced hematological disorders and malignancies.
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Affiliation(s)
- R Dewi
- Biomedical Science Programme and Centre of Applied and Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Z Abdul Hamid
- Biomedical Science Programme and Centre of Applied and Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - N F Rajab
- Biomedical Science Programme and Centre of Applied and Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - S Shuib
- Department of Pathology, Universiti Kebangsaan Malaysia Medical Centre, Jalan Yaacob Latif, Bandar Tun Razak, Kuala Lumpur, Malaysia
| | - Sr Abdul Razak
- Oncological and Radiological Sciences Cluster, Advanced Medical & Dental Institute, Universiti Sains Malaysia, Pulau Pinang, Malaysia
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16
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Holmes TH, Winn LM. DNA Damage and Perturbed Topoisomerase IIα as a Target of 1,4-Benzoquinone Toxicity in Murine Fetal Liver Cells. Toxicol Sci 2019; 171:339-346. [PMID: 31340051 DOI: 10.1093/toxsci/kfz158] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 06/28/2019] [Accepted: 07/11/2019] [Indexed: 01/10/2023] Open
Abstract
Benzene is a ubiquitous environmental pollutant. Recent studies have shown a link between the development of childhood leukemias and maternal benzene exposure, suggesting that these leukemias may be initiated in utero. Benzene crosses the placental barrier however the mechanisms behind in utero benzene toxicity have not been well elucidated. This study is the first to show that the benzene metabolite, benzoquinone (BQ), perturbs fetal topoisomerase IIα (Topo IIα), an enzyme essential for DNA repair. Using cultured murine CD-1 fetal liver cells, this study shows that Topo IIα activity decreases following 24 hours of exposure to BQ (12.5 and 15.625 µM), with the 12.5 µM confirmed to disrupt the c-kit+Lin-Sca-1-Il7rα- population of cells in culture. Pre-treatment with the antioxidant, N-acetylcysteine did not prevent the inhibtion of Topo IIα by BQ. An increase in Topo IIα-DNA covalent adducts was detected following 24-hour exposures to BQ (12.5 and 50 µM). Interestingly, BQ (12.5 µM) exposure did not significantly increase levels of 4-hydroxynonenal (4-HNE), a marker of oxidative stress after 24 hours. However, increased levels of the double-stranded DNA break marker γH2AX were detected following 24 hours of BQ exposure, confirming that Topo IIα-induced breaks are increased in BQ treated cells. This study shows that fetal Topo IIα is perturbed by BQ and suggests that this protein is a target of benzene and may be implicated with in utero benzene toxicity.
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Affiliation(s)
- Trent H Holmes
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Louise M Winn
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.,School of Environmental Studies, Queen's University, Kingston, Ontario, Canada
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17
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Duval R, Bui LC, Mathieu C, Nian Q, Berthelet J, Xu X, Haddad I, Vinh J, Dupret JM, Busi F, Guidez F, Chomienne C, Rodrigues-Lima F. Benzoquinone, a leukemogenic metabolite of benzene, catalytically inhibits the protein tyrosine phosphatase PTPN2 and alters STAT1 signaling. J Biol Chem 2019; 294:12483-12494. [PMID: 31248982 DOI: 10.1074/jbc.ra119.008666] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/21/2019] [Indexed: 12/12/2022] Open
Abstract
Protein tyrosine phosphatase, nonreceptor type 2 (PTPN2) is mainly expressed in hematopoietic cells, where it negatively regulates growth factor and cytokine signaling. PTPN2 is an important regulator of hematopoiesis and immune/inflammatory responses, as evidenced by loss-of-function mutations of PTPN2 in leukemia and lymphoma and knockout mice studies. Benzene is an environmental chemical that causes hematological malignancies, and its hematotoxicity arises from its bioactivation in the bone marrow to electrophilic metabolites, notably 1,4-benzoquinone, a major hematotoxic benzene metabolite. Although the molecular bases for benzene-induced leukemia are not well-understood, it has been suggested that benzene metabolites alter topoisomerases II function and thereby significantly contribute to leukemogenesis. However, several studies indicate that benzene and its hematotoxic metabolites may also promote the leukemogenic process by reacting with other targets and pathways. Interestingly, alterations of cell-signaling pathways, such as Janus kinase (JAK)/signal transducer and activator of transcription (STAT), have been proposed to contribute to benzene-induced malignant blood diseases. We show here that 1,4-benzoquinone directly impairs PTPN2 activity. Mechanistic and kinetic experiments with purified human PTPN2 indicated that this impairment results from the irreversible formation (k inact = 645 m-1·s-1) of a covalent 1,4-benzoquinone adduct at the catalytic cysteine residue of the enzyme. Accordingly, cell experiments revealed that 1,4-benzoquinone exposure irreversibly inhibits cellular PTPN2 and concomitantly increases tyrosine phosphorylation of STAT1 and expression of STAT1-regulated genes. Our results provide molecular and cellular evidence that 1,4-benzoquinone covalently modifies key signaling enzymes, implicating it in benzene-induced malignant blood diseases.
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Affiliation(s)
- Romain Duval
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | - Linh-Chi Bui
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | - Cécile Mathieu
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | - Qing Nian
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | | | - Ximing Xu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Iman Haddad
- ESPCI Paris, PSL Université, USR 3149, CNRS, F-75005 Paris, France
| | - Joelle Vinh
- ESPCI Paris, PSL Université, USR 3149, CNRS, F-75005 Paris, France
| | | | - Florent Busi
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | - Fabien Guidez
- Université de Paris, Institut de Recherche Saint-Louis, UMRS 1131, INSERM, F-75010 Paris, France
| | - Christine Chomienne
- Université de Paris, Institut de Recherche Saint-Louis, UMRS 1131, INSERM, F-75010 Paris, France; Service de Biologie Cellulaire, Assistance Publique des Hôpitaux de Paris (AP-HP), Hôpital Saint Louis, F-75010 Paris, France
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18
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Dalvie ED, Gopas J, Golan-Goldhirsh A, Osheroff N. 6,6'-Dihydroxythiobinupharidine as a poison of human type II topoisomerases. Bioorg Med Chem Lett 2019; 29:1881-1885. [PMID: 31182315 DOI: 10.1016/j.bmcl.2019.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/28/2019] [Accepted: 06/01/2019] [Indexed: 12/31/2022]
Abstract
A number of natural products with medicinal properties increase DNA cleavage mediated by type II topoisomerases. In an effort to identify additional natural compounds that affect the activity of human type II topoisomerases, a blind screen of a library of 341 Mediterranean plant extracts was conducted. Extracts from Nuphar lutea, the yellow water lily, were identified in this screen. N. lutea has been used in traditional medicine by a variety of indigenous populations. The active compound in N. lutea, 6,6'-dihydroxythiobinupharidine, was found to enhance DNA cleavage mediated by human topoisomerase IIα and IIβ ∼8-fold and ∼3-fold, respectively. Mechanistic studies with topoisomerase IIα indicate that 6,6'-dihydroxythiobinupharidine is a "covalent poison" that acts by adducting the enzyme outside of the DNA cleavage-ligation active site and requires the N-terminal domain of the protein for its activity. Results suggest that some of the medicinal properties of N. lutea may result from the interactions between 6,6'-dihydroxythiobinupharidine and the human type II enzymes.
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Affiliation(s)
- Esha D Dalvie
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
| | - Jacob Gopas
- Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel; Department of Oncology, Soroka University Medical Center, Beer Sheva 84105, Israel
| | - Avi Golan-Goldhirsh
- The Jacob Blaustein Institutes for Desert Research, French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion University of the Negev, Sede Boqer Campus, Beer Sheva 84990, Israel
| | - Neil Osheroff
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA; Department of Medicine (Hematology/Oncology), Vanderbilt University School of Medicine, Nashville, TN 37232-6307, USA; VA Tennessee Valley Healthcare System, Nashville, TN 37212, USA.
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19
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Bariar B, Vestal CG, Deem B, Goodenow D, Ughetta M, Engledove RW, Sahyouni M, Richardson C. Bioflavonoids promote stable translocations between MLL-AF9 breakpoint cluster regions independent of normal chromosomal context: Model system to screen environmental risks. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:154-167. [PMID: 30387535 PMCID: PMC6363851 DOI: 10.1002/em.22245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/26/2018] [Accepted: 08/06/2018] [Indexed: 06/08/2023]
Abstract
Infant acute leukemias are aggressive and characterized by rapid onset after birth. The majority harbor translocations involving the MLL gene with AF9 as one of its most common fusion partners. MLL and AF9 loci contain breakpoint cluster regions (bcrs) with sequences hypothesized to be targets of topoisomerase II inhibitors that promote translocation formation. Overlap of MLL bcr sequences associated with both infant acute leukemia and therapy-related leukemia following exposure to the topoisomerase II inhibitor etoposide led to the hypothesis that exposure during pregnancy to biochemically similar compounds may promote infant acute leukemia. We established a reporter system to systematically quantitate and stratify the potential for such compounds to promote chromosomal translocations between the MLL and AF9 bcrs analogous to those in infant leukemia. We show bioflavonoids genistein and quercetin most biochemically similar to etoposide have a strong association with MLL-AF9 bcr translocations, while kaempferol, fisetin, flavone, and myricetin have a weak but consistent association, and other compounds have a minimal association in both embryonic stem (ES) and hematopoietic stem cell (HSC) populations. The frequency of translocations induced by bioflavonoids at later stages of myelopoiesis is significantly reduced by more than one log. The MLL and AF9 bcrs are sensitive to these agents and recombinogenic independent of their native context suggesting bcr sequences themselves are drivers of illegitimate DNA repair reactions and translocations, not generation of functional oncogenic fusions. This system provides for rapid systematic screening of relative risk, dose dependence, and combinatorial impact of multitudes of dietary and environmental exposures on MLL-AF9 translocations. Environ. Mol. Mutagen. 60: 154-167, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Bhawana Bariar
- University of North Carolina at Charlotte, Dept of Biological Sciences, 9201 University City Boulevard, Charlotte NC, 28223
| | - C. Greer Vestal
- University of North Carolina at Charlotte, Dept of Biological Sciences, 9201 University City Boulevard, Charlotte NC, 28223
| | - Bradley Deem
- University of North Carolina at Charlotte, Dept of Biological Sciences, 9201 University City Boulevard, Charlotte NC, 28223
| | - Donna Goodenow
- University of North Carolina at Charlotte, Dept of Biological Sciences, 9201 University City Boulevard, Charlotte NC, 28223
| | - Mimi Ughetta
- University of North Carolina at Charlotte, Dept of Biological Sciences, 9201 University City Boulevard, Charlotte NC, 28223
| | - R. Warren Engledove
- University of North Carolina at Charlotte, Dept of Biological Sciences, 9201 University City Boulevard, Charlotte NC, 28223
| | - Mark Sahyouni
- University of North Carolina at Charlotte, Dept of Biological Sciences, 9201 University City Boulevard, Charlotte NC, 28223
| | - Christine Richardson
- University of North Carolina at Charlotte, Dept of Biological Sciences, 9201 University City Boulevard, Charlotte NC, 28223
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20
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Gouda MA, Berghot MA, Abd El-Ghani GE, Khalil AEGM. Synthesis of Some Novel 4-(Furan-2-yl)-5,6-dimethylpyridines. J Heterocycl Chem 2018; 55:1935-1941. [DOI: 10.1002/jhet.3231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Affiliation(s)
- Moustafa A. Gouda
- Department of Chemistry; Faculty of Science and Arts, Taibah University; Ulla Saudi Arabia
- Department of Chemistry, Faculty of Science; Mansoura University; El-Gomhoria Street Mansoura 35516 Egypt
| | - Moged A. Berghot
- Department of Chemistry, Faculty of Science; Mansoura University; El-Gomhoria Street Mansoura 35516 Egypt
| | - Ghada E. Abd El-Ghani
- Department of Chemistry, Faculty of Science; Mansoura University; El-Gomhoria Street Mansoura 35516 Egypt
| | - Abd El-Galil M. Khalil
- Department of Chemistry, Faculty of Science; Mansoura University; El-Gomhoria Street Mansoura 35516 Egypt
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21
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Mahalapbutr P, Chusuth P, Kungwan N, Chavasiri W, Wolschann P, Rungrotmongkol T. Molecular recognition of naphthoquinone-containing compounds against human DNA topoisomerase IIα ATPase domain: A molecular modeling study. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.10.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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22
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Hall SR, Toulany J, Bennett LG, Martinez-Farina CF, Robertson AW, Jakeman DL, Goralski KB. Jadomycins Inhibit Type II Topoisomerases and Promote DNA Damage and Apoptosis in Multidrug-Resistant Triple-Negative Breast Cancer Cells. J Pharmacol Exp Ther 2017; 363:196-210. [PMID: 28904004 DOI: 10.1124/jpet.117.241125] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 09/07/2017] [Indexed: 12/24/2022] Open
Abstract
Jadomycins are natural products that kill drug-sensitive and multidrug-resistant (MDR) breast cancer cells. To date, the cytotoxic activity of jadomycins has never been tested in MDR breast cancer cells that are also triple negative. Additionally, there is only a rudimentary understanding of how jadomycins cause cancer cell death, which includes the induction of intracellular reactive oxygen species (ROS). We first created a paclitaxel-resistant, triple-negative breast cancer cell line [paclitaxel-resistant MDA-MB-231 breast cancer cells (231-TXL)] from drug-sensitive control MDA-MB-231 cells (231-CON). Using thiazolyl blue methyltetrazolium bromide cell viability-measuring assays, jadomycins B, S, and F were found to be equipotent in drug-sensitive 231-CON and MDR 231-TXL cells; and using ROS-detecting assays, these jadomycins were determined to increase ROS activity in both cell lines by up to 7.3-fold. Jadomycins caused DNA double-strand breaks in 231-CON and 231-TXL cells as measured by γH2AX Western blotting. Coincubation with the antioxidant N-acetyl cysteine or pro-oxidant auranofin did not affect jadomycin-mediated DNA damage. Jadomycins induced apoptosis in 231-CON and 231-TXL cells as measured by annexin V affinity assays, a process that was retained when ROS were inhibited. This indicated that jadomycins are capable of inducing MDA-MB-231 apoptotic cell death independently of ROS activity. Using quantitative polymerase chain reaction, Western blotting, and direct topoisomerase inhibition assays, it was determined that jadomycins inhibit type II topoisomerases and that jadomycins B and F selectively poison topoisomerase IIβ We therefore propose novel mechanisms through which jadomycins induce breast cancer cell death independently of ROS activity, through inhibition or poisoning of type II topoisomerases and the induction of DNA damage and apoptosis.
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Affiliation(s)
- Steven R Hall
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jay Toulany
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Leah G Bennett
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Camilo F Martinez-Farina
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Andrew W Robertson
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - David L Jakeman
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kerry B Goralski
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
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23
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Yu X, Davenport JW, Urtishak KA, Carillo ML, Gosai SJ, Kolaris CP, Byl JAW, Rappaport EF, Osheroff N, Gregory BD, Felix CA. Genome-wide TOP2A DNA cleavage is biased toward translocated and highly transcribed loci. Genome Res 2017; 27:1238-1249. [PMID: 28385713 PMCID: PMC5495075 DOI: 10.1101/gr.211615.116] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Accepted: 04/05/2017] [Indexed: 01/22/2023]
Abstract
Type II topoisomerases orchestrate proper DNA topology, and they are the targets of anti-cancer drugs that cause treatment-related leukemias with balanced translocations. Here, we develop a high-throughput sequencing technology to define TOP2 cleavage sites at single-base precision, and use the technology to characterize TOP2A cleavage genome-wide in the human K562 leukemia cell line. We find that TOP2A cleavage has functionally conserved local sequence preferences, occurs in cleavage cluster regions (CCRs), and is enriched in introns and lincRNA loci. TOP2A CCRs are biased toward the distal regions of gene bodies, and TOP2 poisons cause a proximal shift in their distribution. We find high TOP2A cleavage levels in genes involved in translocations in TOP2 poison–related leukemia. In addition, we find that a large proportion of genes involved in oncogenic translocations overall contain TOP2A CCRs. The TOP2A cleavage of coding and lincRNA genes is independently associated with both length and transcript abundance. Comparisons to ENCODE data reveal distinct TOP2A CCR clusters that overlap with marks of transcription, open chromatin, and enhancers. Our findings implicate TOP2A cleavage as a broad DNA damage mechanism in oncogenic translocations as well as a functional role of TOP2A cleavage in regulating transcription elongation and gene activation.
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Affiliation(s)
- Xiang Yu
- Biology Department, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - James W Davenport
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Karen A Urtishak
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Marie L Carillo
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Sager J Gosai
- Biology Department, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Christos P Kolaris
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Jo Ann W Byl
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Eric F Rappaport
- NAPCore, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Neil Osheroff
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232, USA.,Department of Medicine (Hematology/Oncology), Vanderbilt University, Nashville, Tennessee 37232, USA.,VA Tennessee Valley Healthcare System, Nashville, Tennessee 37212, USA
| | - Brian D Gregory
- Biology Department, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Carolyn A Felix
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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24
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Infante Lara L, Sledge A, Laradji A, Okoro CO, Osheroff N. Novel trifluoromethylated 9-amino-3,4-dihydroacridin-1(2H)-ones act as covalent poisons of human topoisomerase IIα. Bioorg Med Chem Lett 2016; 27:586-589. [PMID: 27998679 DOI: 10.1016/j.bmcl.2016.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/02/2016] [Accepted: 12/02/2016] [Indexed: 10/20/2022]
Abstract
A number of topoisomerase II-targeted anticancer drugs, including amsacrine, utilize an acridine or related aromatic core as a scaffold. Therefore, to further explore the potential of acridine-related compounds to act as topoisomerase II poisons, we synthesized a series of novel trifluoromethylated 9-amino-3,4-dihydroacridin-1(2H)-one derivatives and examined their ability to enhance DNA cleavage mediated by human topoisomerase IIα. Derivatives containing a H, Cl, F, and Br at C7 enhanced enzyme-mediated double-stranded DNA cleavage ∼5.5- to 8.5-fold over baseline, but were less potent than amsacrine. The inclusion of an amino group at C9 was critical for activity. The compounds lost their activity against topoisomerase IIα in the presence of a reducing agent, displayed no activity against the catalytic core of topoisomerase IIα, and inhibited DNA cleavage when incubated with the enzyme prior to the addition of DNA. These findings strongly suggest that the compounds act as covalent, rather than interfacial, topoisomerase II poisons.
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Affiliation(s)
- Lorena Infante Lara
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Alexis Sledge
- Department of Chemistry, Tennessee State University, Nashville, TN 37209-1561, USA
| | - Amine Laradji
- Department of Chemistry, Tennessee State University, Nashville, TN 37209-1561, USA
| | - Cosmas O Okoro
- Department of Chemistry, Tennessee State University, Nashville, TN 37209-1561, USA.
| | - Neil Osheroff
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Medicine (Hematology/Oncology), Vanderbilt University School of Medicine, Nashville, TN 37232, USA; VA Tennessee Valley Healthcare System, Nashville, TN 37212, USA.
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25
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Inhibition of Glucose-6-Phosphate Dehydrogenase Could Enhance 1,4-Benzoquinone-Induced Oxidative Damage in K562 Cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:3912515. [PMID: 27656260 PMCID: PMC5021878 DOI: 10.1155/2016/3912515] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/28/2016] [Accepted: 07/31/2016] [Indexed: 11/30/2022]
Abstract
Benzene is a chemical contaminant widespread in industrial and living environments. The oxidative metabolites of benzene induce toxicity involving oxidative damage. Protecting cells and cell membranes from oxidative damage, glucose-6-phosphate dehydrogenase (G6PD) maintains the reduced state of glutathione (GSH). This study aims to investigate whether the downregulation of G6PD in K562 cell line can influence the oxidative toxicity induced by 1,4-benzoquinone (BQ). G6PD was inhibited in K562 cell line transfected with the specific siRNA of G6PD gene. An empty vector was transfected in the control group. Results revealed that G6PD was significantly upregulated in the control cells and in the cells with inhibited G6PD after they were exposed to BQ. The NADPH/NADP and GSH/GSSG ratio were significantly lower in the cells with inhibited G6PD than in the control cells at the same BQ concentration. The relative reactive oxygen species (ROS) level and DNA oxidative damage were significantly increased in the cell line with inhibited G6PD. The apoptotic rate and G2 phase arrest were also significantly higher in the cells with inhibited G6PD and exposed to BQ than in the control cells. Our results suggested that G6PD inhibition could reduce GSH activity and alleviate oxidative damage. G6PD deficiency is also a possible susceptible risk factor of benzene exposure.
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26
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Son MY, Deng CX, Hoeijmarkers JH, Rebel VI, Hasty P. A mechanism for 1,4-Benzoquinone-induced genotoxicity. Oncotarget 2016; 7:46433-46447. [PMID: 27340773 PMCID: PMC5216808 DOI: 10.18632/oncotarget.10184] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 05/22/2016] [Indexed: 12/30/2022] Open
Abstract
Benzene is a common environmental toxin and its metabolite, 1-4-Benzoquinone (BQ) causes hematopoietic cancers like myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). BQ has not been comprehensively assessed for its impact on genome maintenance, limiting our understanding of the true health risks associated with benzene exposure and our ability to identify people with increased sensitivity to this genotoxin. Here we analyze the impact BQ exposure has on wild type and DNA repair-defective mouse embryonic stem (ES) cells and wild type human cells. We find that double strand break (DSB) repair and replication fork maintenance pathways including homologous recombination (HR) and Fanconi anemia (FA) suppress BQ toxicity. BQ-induced damage efficiently stalls replication forks, yet poorly induces ATR/DNA-PKCS responses. Furthermore, the pattern of BQ-induced γH2AX and 53BP1foci is consistent with the formation of poly(ADP-ribose) polymerase 1 (PARP1)-stabilized regressed replication forks. At a biochemical level, BQ inhibited topoisomerase 1 (topo1)-mediated DNA ligation and nicking in vitro; thus providing mechanism for the cellular phenotype. These data are consistent with a model that proposes BQ interferes with type I topoisomerase's ability to maintain replication fork restart and progression leading to chromosomal instability that has the potential to cause hematopoietic cancers like MDS and AML.
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Affiliation(s)
- Mi Young Son
- Department of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Chu-Xia Deng
- Faculty of Health Sciences, University of Macau, Macau SAR China
| | - Jan H. Hoeijmarkers
- Department of Genetics, Cancer Genomics Netherlands, Erasmus MC, The Netherlands
| | - Vivienne I. Rebel
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- The Cancer Therapy Research Center, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- The Barshop Center of Aging, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Greehey Children's Cancer Research Center, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Current address: BioAffinity, San Antonio, Texas, USA
| | - Paul Hasty
- Department of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- The Cancer Therapy Research Center, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- The Barshop Center of Aging, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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27
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Urtishak KA, Robinson BW, Rappaport EF, Sarezky MD, Biegel JA, Nichols KE, Wilmoth DM, Wang LS, Stern JW, Felix CA. Unique Familial MLL(KMT2A)-Rearranged Precursor B-Cell Infant Acute Lymphoblastic Leukemia in Non-twin Siblings. Pediatr Blood Cancer 2016; 63:1175-80. [PMID: 26999444 DOI: 10.1002/pbc.25957] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/29/2016] [Accepted: 02/01/2016] [Indexed: 12/27/2022]
Abstract
BACKGROUND Infant acute lymphoblastic leukemia (ALL) has never occurred in families except for the ∼100% concordant cases in monozygous twins attributed to twin-to-twin metastases. We report the first kindred with infant ALL in non-twin siblings. The siblings were diagnosed with MLL-rearranged (MLL-R) ALL 26 months apart. The second affected sibling had an unaffected dichorionic monozygous co-twin. Both had fatal outcomes. PROCEDURES Translocations were characterized by karyotype, FISH, multiplex FISH, and MLL breakpoint cluster region (bcr) Southern blot analysis. Breakpoint junctions and fusion transcripts were cloned by PCR. TP53 mutation and NADPH quinone oxidorecuctase 1 (NQO1) C609T analyses were performed, and pedigree history and parental occupations were ascertained. The likelihood of chance occurrence of infant ALL in non-twin siblings was computed based on a binomial distribution. Zygosity was determined by single nucleotide polymorphism (SNP) array. RESULTS The translocations were not related or vertically transmitted. The complex karyotype of the proband's ALL had chromosome 2, 3, 4, and 11 abnormalities causing a 5'-MLL-AFF1-3' fusion and a non-productive rearrangement of 3'MLL with a chromosome 3q intergenic region. The affected twin's ALL exhibited a simple t(4;11). The complex karyotype of the proband's ALL suggested a genotoxic insult, but no exposure was identified. There was no germline TP53 mutation. The NQO1 C609T risk allele was absent. The likelihood of infant ALL occurring in non-twin siblings by chance alone is one in 1.198 × 10(9) families. CONCLUSIONS Whether because of a deleterious transplacental exposure, novel predisposition syndrome, or exceedingly rare chance occurrence, MLL-R infant ALL can occur in non-twin siblings. The discordant occurrence of infant ALL in the monozygous twins was likely because they were dichorionic.
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Affiliation(s)
- Karen A Urtishak
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Blaine W Robinson
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Eric F Rappaport
- Nucleic Acids & Protein Core Facility, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Margaret D Sarezky
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Jaclyn A Biegel
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kim E Nichols
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Donna M Wilmoth
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Li-San Wang
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Julie W Stern
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Carolyn A Felix
- Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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28
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Vann KR, Ekiz G, Zencir S, Bedir E, Topcu Z, Osheroff N. Effects of Secondary Metabolites from the Fungus Septofusidium berolinense on DNA Cleavage Mediated by Human Topoisomerase IIα. Chem Res Toxicol 2016; 29:415-20. [PMID: 26894873 DOI: 10.1021/acs.chemrestox.6b00009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Two metabolites from the ascomycete fungus Septofusidium berolinense were recently identified as having antineoplastic activity [Ekiz et al. (2015) J. Antibiot. , DOI: 10.1038/ja.2015.84]. However, the basis for this activity is not known. One of the compounds [3,6-dihydroxy-2-propylbenzaldehyde (GE-1)] is a hydroquinone, and the other [2-hydroxymethyl-3-propylcyclohexa-2,5-diene-1,4-dione (GE-2)] is a quinone. Because some hydroquinones and quinones act as topoisomerase II poisons, the effects of GE-1 and GE-2 on DNA cleavage mediated by human topoisomerase IIα were assessed. GE-2 enhanced DNA cleavage ∼4-fold and induced scission with a site specificity similar to that of the anticancer drug etoposide. Similar to other quinone-based topoisomerase II poisons, GE-2 displayed several hallmark characteristics of covalent topoisomerase II poisons, including (1) the inability to poison a topoisomerase IIα construct that lacks the N-terminal domain, (2) the inhibition of DNA cleavage when the compound was incubated with the enzyme prior to the addition of plasmid, and (3) the loss of poisoning activity in the presence of a reducing agent. In contrast to GE-2, GE-1 did not enhance DNA cleavage mediated by topoisomerase IIα except at very high concentrations. However, the activity and potency of the metabolite were dramatically enhanced under oxidizing conditions. These results suggest that topoisomerase IIα may play a role in mediating the cytotoxic effects of these fungal metabolites.
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Affiliation(s)
| | | | - Sevil Zencir
- Department of Medical Biology, Faculty of Medicine, Pamukkale University , 20070 Denizli, Turkey
| | | | | | - Neil Osheroff
- VA Tennessee Valley Healthcare System , Nashville, Tennessee 37212, United States
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29
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Carbonari D, Chiarella P, Mansi A, Pigini D, Iavicoli S, Tranfo G. Biomarkers of susceptibility following benzene exposure: influence of genetic polymorphisms on benzene metabolism and health effects. Biomark Med 2016; 10:145-63. [PMID: 26764284 DOI: 10.2217/bmm.15.106] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Benzene is a ubiquitous occupational and environmental pollutant. Improved industrial hygiene allowed airborne concentrations close to the environmental context (1-1000 µg/m(3)). Conversely, new limits for benzene levels in urban air were set (5 µg/m(3)). The biomonitoring of exposure to such low benzene concentrations are performed measuring specific and sensitive biomarkers such as S-phenylmercapturic acid, trans, trans-muconic acid and urinary benzene: many studies referred high variability in the levels of these biomarkers, suggesting the involvement of polymorphic metabolic genes in the individual susceptibility to benzene toxicity. We reviewed the influence of metabolic polymorphisms on the biomarkers levels of benzene exposure and effect, in order to understand the real impact of benzene exposure on subjects with increased susceptibility.
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Affiliation(s)
- Damiano Carbonari
- INAIL Reaserch, Department of Occupational & Environmental Medicine, Epidemiology & Hygiene, Via Fontana Candida 1 - 00040 Monte Porzio Catone (RM), Italy
| | - Pieranna Chiarella
- INAIL Reaserch, Department of Occupational & Environmental Medicine, Epidemiology & Hygiene, Via Fontana Candida 1 - 00040 Monte Porzio Catone (RM), Italy
| | - Antonella Mansi
- INAIL Reaserch, Department of Occupational & Environmental Medicine, Epidemiology & Hygiene, Via Fontana Candida 1 - 00040 Monte Porzio Catone (RM), Italy
| | - Daniela Pigini
- INAIL Reaserch, Department of Occupational & Environmental Medicine, Epidemiology & Hygiene, Via Fontana Candida 1 - 00040 Monte Porzio Catone (RM), Italy
| | - Sergio Iavicoli
- INAIL Reaserch, Department of Occupational & Environmental Medicine, Epidemiology & Hygiene, Via Fontana Candida 1 - 00040 Monte Porzio Catone (RM), Italy
| | - Giovanna Tranfo
- INAIL Reaserch, Department of Occupational & Environmental Medicine, Epidemiology & Hygiene, Via Fontana Candida 1 - 00040 Monte Porzio Catone (RM), Italy
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30
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Choi J, Polcher A, Joas A. Systematic literature review on Parkinson's disease and Childhood Leukaemia and mode of actions for pesticides. ACTA ACUST UNITED AC 2016. [DOI: 10.2903/sp.efsa.2016.en-955] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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31
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Thys RG, Lehman CE, Pierce LCT, Wang YH. Environmental and chemotherapeutic agents induce breakage at genes involved in leukemia-causing gene rearrangements in human hematopoietic stem/progenitor cells. Mutat Res 2015; 779:86-95. [PMID: 26163765 PMCID: PMC4808301 DOI: 10.1016/j.mrfmmm.2015.06.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 05/27/2015] [Accepted: 06/23/2015] [Indexed: 01/27/2023]
Abstract
Hematopoietic stem and progenitor cells (HSPCs) give rise to all of the cells that make up the hematopoietic system in the human body, making their stability and resilience especially important. Damage to these cells can severely impact cell development and has the potential to cause diseases, such as leukemia. Leukemia-causing chromosomal rearrangements have largely been studied in the context of radiation exposure and are formed by a multi-step process, including an initial DNA breakage and fusion of the free DNA ends. However, the mechanism for DNA breakage in patients without previous radiation exposure is unclear. Here, we investigate the role of non-cytotoxic levels of environmental factors, benzene, and diethylnitrosamine (DEN), and chemotherapeutic agents, etoposide, and doxorubicin, in generating DNA breakage at the patient breakpoint hotspots of the MLL and CBFB genes in human HSPCs. These conditions represent exposure to chemicals encountered daily or residual doses from chemotherapeutic drugs. Exposure of HSPCs to non-cytotoxic levels of environmental chemicals or chemotherapeutic agents causes DNA breakage at preferential sites in the human genome, including the leukemia-related genes MLL and CBFB. Though benzene, etoposide, and doxorubicin have previously been linked to leukemia formation, this is the first study to demonstrate a role for DEN in the generation of DNA breakage at leukemia-specific sites. These chemical-induced DNA breakpoints coincide with sites of predicted topoisomerase II cleavage. The distribution of breakpoints by exposure to non-cytotoxic levels of chemicals showed a similar pattern to fusion breakpoints in leukemia patients. Our findings demonstrate that HSPCs exposed to non-cytotoxic levels of environmental chemicals and chemotherapeutic agents are prone to topoisomerase II-mediated DNA damage at the leukemia-associated genes MLL and CBFB. These data suggest a role for long-term environmental chemical or residual chemotherapeutic drug exposure in generation of DNA breakage at sites with a propensity to form leukemia-causing gene rearrangements.
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Affiliation(s)
- Ryan G Thys
- Department of Cancer Biology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1016, USA.
| | - Christine E Lehman
- Department of Cancer Biology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1016, USA.
| | | | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, VA 22908-0733, USA.
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32
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Vann KR, Sedgeman CA, Gopas J, Golan-Goldhirsh A, Osheroff N. Effects of Olive Metabolites on DNA Cleavage Mediated by Human Type II Topoisomerases. Biochemistry 2015; 54:4531-41. [PMID: 26132160 PMCID: PMC4520624 DOI: 10.1021/acs.biochem.5b00162] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
![]()
Several
naturally occurring dietary polyphenols with chemopreventive
or anticancer properties are topoisomerase II poisons. To identify
additional phytochemicals that enhance topoisomerase II-mediated DNA
cleavage, a library of 341 Mediterranean plant extracts was screened
for activity against human topoisomerase IIα. An extract from Phillyrea latifolia L., a member of the olive tree family,
displayed high activity against the human enzyme. On the basis of
previous metabolomics studies, we identified several polyphenols (hydroxytyrosol,
oleuropein, verbascoside, tyrosol, and caffeic acid) as potential
candidates for topoisomerase II poisons. Of these, hydroxytyrosol,
oleuropein, and verbascoside enhanced topoisomerase II-mediated DNA
cleavage. The potency of these olive metabolites increased 10–100-fold
in the presence of an oxidant. Hydroxytyrosol, oleuropein, and verbascoside
displayed hallmark characteristics of covalent topoisomerase II poisons.
(1) The activity of the metabolites was abrogated by a reducing agent.
(2) Compounds inhibited topoisomerase II activity when they were incubated
with the enzyme prior to the addition of DNA. (3) Compounds were unable
to poison a topoisomerase IIα construct that lacked the N-terminal
domain. Because hydroxytyrosol, oleuropein, and verbascoside are broadly
distributed across the olive family, extracts from the leaves, bark,
and fruit of 11 olive tree species were tested for activity against
human topoisomerase IIα. Several of the extracts enhanced enzyme-mediated
DNA cleavage. Finally, a commercial olive leaf supplement and extra
virgin olive oils pressed from a variety of Olea europea subspecies enhanced DNA cleavage mediated by topoisomerase IIα.
Thus, olive metabolites appear to act as topoisomerase II poisons
in complex formulations intended for human dietary consumption.
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Affiliation(s)
| | | | - Jacob Gopas
- ∥Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.,⊥Department of Oncology, Soroka University Medical Center, Beer Sheva 84105, Israel
| | - Avi Golan-Goldhirsh
- @The Jacob Blaustein Institutes for Desert Research (BIDR), French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion University of the Negev, Sede Boqer Campus, Beer Sheva 84990, Israel
| | - Neil Osheroff
- §VA Tennessee Valley Healthcare System, Nashville, Tennessee 37212, United States
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33
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Lindsey RH, Pendleton M, Ashley RE, Mercer SL, Deweese JE, Osheroff N. Catalytic core of human topoisomerase IIα: insights into enzyme-DNA interactions and drug mechanism. Biochemistry 2014; 53:6595-602. [PMID: 25280269 PMCID: PMC4204876 DOI: 10.1021/bi5010816] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Coordination between the N-terminal gate and the catalytic core of topoisomerase II allows the proper capture, cleavage, and transport of DNA during the catalytic cycle. Because the activities of these domains are tightly linked, it has been difficult to discern their individual contributions to enzyme-DNA interactions and drug mechanism. To further address the roles of these domains, we analyzed the activity of the catalytic core of human topoisomerase IIα. The catalytic core and the wild-type enzyme both maintained higher levels of cleavage with negatively (as compared to positively) supercoiled plasmid, indicating that the ability to distinguish supercoil handedness is embedded within the catalytic core. However, the catalytic core alone displayed little ability to cleave DNA substrates that did not intrinsically provide the enzyme with a transport segment (i.e., substrates that did not contain crossovers). Finally, in contrast to interfacial topoisomerase II poisons, covalent poisons did not enhance DNA cleavage mediated by the catalytic core. This distinction allowed us to further characterize the mechanism of etoposide quinone, a drug metabolite that functions primarily as a covalent poison. Etoposide quinone retained some ability to enhance DNA cleavage mediated by the catalytic core, indicating that it still can function as an interfacial poison. These results further define the distinct contributions of the N-terminal gate and the catalytic core to topoisomerase II function. The catalytic core senses the handedness of DNA supercoils during cleavage, while the N-terminal gate is critical for capturing the transport segment and for the activity of covalent poisons.
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Affiliation(s)
- R Hunter Lindsey
- Department of Biochemistry, ‡Department of Pharmacology, and §Department of Medicine (Hematology/Oncology), Vanderbilt University School of Medicine , Nashville, Tennessee 37232-0146, United States
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34
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Bariar B, Vestal CG, Richardson C. Long-term effects of chromatin remodeling and DNA damage in stem cells induced by environmental and dietary agents. J Environ Pathol Toxicol Oncol 2014; 32:307-27. [PMID: 24579784 DOI: 10.1615/jenvironpatholtoxicoloncol.2013007980] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The presence of histones acts as a barrier to protein access; thus chromatin remodeling must occur for essential processes such as transcription and replication. In conjunction with histone modifications, DNA methylation plays critical roles in gene silencing through chromatin remodeling. Chromatin remodeling is also interconnected with the DNA damage response, maintenance of stem cell properties, and cell differentiation programs. Chromatin modifications have increasingly been shown to produce long-lasting alterations in chromatin structure and transcription. Recent studies have shown environmental exposures in utero have the potential to alter normal developmental signaling networks, physiologic responses, and disease susceptibility later in life during a process known as developmental reprogramming. In this review we discuss the long-term impact of exposure to environmental compounds, the chromatin modifications that they induce, and the differentiation and developmental programs of multiple stem and progenitor cell types altered by exposure. The main focus is to highlight agents present in the human lifestyle that have the potential to promote epigenetic changes that impact developmental programs of specific cell types, may promote tumorigenesis through altering epigenetic marks, and may be transgenerational, for example, those able to be transmitted through multiple cell divisions.
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Affiliation(s)
- Bhawana Bariar
- Department of Biology, University of North Carolina at Charlotte, Charlotte, NC
| | - C Greer Vestal
- Department of Biology, University of North Carolina at Charlotte, Charlotte, NC
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35
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Gao R, Schellenberg MJ, Huang SYN, Abdelmalak M, Marchand C, Nitiss KC, Nitiss JL, Williams RS, Pommier Y. Proteolytic degradation of topoisomerase II (Top2) enables the processing of Top2·DNA and Top2·RNA covalent complexes by tyrosyl-DNA-phosphodiesterase 2 (TDP2). J Biol Chem 2014; 289:17960-9. [PMID: 24808172 DOI: 10.1074/jbc.m114.565374] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Eukaryotic type II topoisomerases (Top2α and Top2β) are homodimeric enzymes; they are essential for altering DNA topology by the formation of normally transient double strand DNA cleavage. Anticancer drugs (etoposide, doxorubicin, and mitoxantrone) and also Top2 oxidation and DNA helical alterations cause potentially irreversible Top2·DNA cleavage complexes (Top2cc), leading to Top2-linked DNA breaks. Top2cc are the therapeutic mechanism for killing cancer cells. Yet Top2cc can also generate recombination, translocations, and apoptosis in normal cells. The Top2 protein-DNA covalent complexes are excised (in part) by tyrosyl-DNA-phosphodiesterase 2 (TDP2/TTRAP/EAP2/VPg unlinkase). In this study, we show that irreversible Top2cc induced in suicidal substrates are not processed by TDP2 unless they first undergo proteolytic processing or denaturation. We also demonstrate that TDP2 is most efficient when the DNA attached to the tyrosyl is in a single-stranded configuration and that TDP2 can efficiently remove a tyrosine linked to a single misincorporated ribonucleotide or to polyribonucleotides, which expands the TDP2 catalytic profile with RNA substrates. The 1.6-Å resolution crystal structure of TDP2 bound to a substrate bearing a 5'-ribonucleotide defines a mechanism through which RNA can be accommodated in the TDP2 active site, albeit in a strained conformation.
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Affiliation(s)
- Rui Gao
- From the Laboratory of Molecular Pharmacology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Matthew J Schellenberg
- the Laboratory of Structural Biology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, and
| | - Shar-Yin N Huang
- From the Laboratory of Molecular Pharmacology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Monica Abdelmalak
- From the Laboratory of Molecular Pharmacology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Christophe Marchand
- From the Laboratory of Molecular Pharmacology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Karin C Nitiss
- the Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois, Rockford, Illinois 61107
| | - John L Nitiss
- the Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois, Rockford, Illinois 61107
| | - R Scott Williams
- the Laboratory of Structural Biology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, and
| | - Yves Pommier
- From the Laboratory of Molecular Pharmacology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892,
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36
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Smith NA, Byl JAW, Mercer SL, Deweese JE, Osheroff N. Etoposide quinone is a covalent poison of human topoisomerase IIβ. Biochemistry 2014; 53:3229-36. [PMID: 24766193 PMCID: PMC4033626 DOI: 10.1021/bi500421q] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
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Etoposide is a topoisomerase II poison
that is utilized to treat
a broad spectrum of human cancers. Despite its wide clinical use,
2–3% of patients treated with etoposide eventually develop
treatment-related acute myeloid leukemias (t-AMLs) characterized by
rearrangements of the MLL gene. The molecular basis
underlying the development of these t-AMLs is not well understood;
however, previous studies have implicated etoposide metabolites (i.e.,
etoposide quinone) and topoisomerase IIβ in the leukemogenic
process. Although interactions between etoposide quinone and topoisomerase
IIα have been characterized, the effects of the drug metabolite
on the activity of human topoisomerase IIβ have not been reported.
Thus, we examined the ability of etoposide quinone to poison human
topoisomerase IIβ. The quinone induced ∼4 times more
enzyme-mediated DNA cleavage than did the parent drug. Furthermore,
the potency of etoposide quinone was ∼2 times greater against
topoisomerase IIβ than it was against topoisomerase IIα,
and the drug reacted ∼2–4 times faster with the β
isoform. Etoposide quinone induced a higher ratio of double- to single-stranded
breaks than etoposide, and its activity was less dependent on ATP.
Whereas etoposide acts as an interfacial topoisomerase II poison,
etoposide quinone displayed all of the hallmarks of a covalent poison:
the activity of the metabolite was abolished by reducing agents, and
the compound inactivated topoisomerase IIβ when it was incubated
with the enzyme prior to the addition of DNA. These results are consistent
with the hypothesis that etoposide quinone contributes to etoposide-related
leukemogenesis through an interaction with topoisomerase IIβ.
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Affiliation(s)
- Nicholas A Smith
- Departments of †Biochemistry, ‡Medicine (Hematology/Oncology), and §Pharmacology, Vanderbilt University School of Medicine , Nashville, Tennessee 37232-0146, United States
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37
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Ashley RE, Osheroff N. Natural products as topoisomerase II poisons: effects of thymoquinone on DNA cleavage mediated by human topoisomerase IIα. Chem Res Toxicol 2014; 27:787-93. [PMID: 24650156 PMCID: PMC4033629 DOI: 10.1021/tx400453v] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
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The
seeds of Nigella sativa (often
referred to as black seed) have long been utilized as a medicinal
herb in Middle Eastern, Northern African, and Indian cultures. Historically,
black seed has been used to treat a variety of illnesses associated
with inflammation. More recent studies have found that it induces
apoptosis and displays anticancer activity in animal and cellular
models. The major bioactive compound of black seed is thymoquinone,
which shares structural features with 1,4-benzoquinone and other covalent
topoisomerase II poisons. Because a number of anticancer drugs target
type II topoisomerases, we determined the effects of thymoquinone
and a series of related quinones on human topoisomerase IIα.
Thymoquinone enhanced enzyme-mediated DNA cleavage ∼5-fold,
which is similar to the increase seen with the anticancer drug etoposide.
In order to enhance cleavage, compounds had to have at least two positions
available for acylation. Furthermore, activity was decreased by the
inclusion of electron-donating groups or bulky substituents. As predicted
for a covalent topoisomerase II poison, the activity of thymoquinone
(and related compounds) was abrogated by the addition of a reducing
agent. Also, thymoquinone inhibited topoisomerase IIα activity
when incubated with the enzyme prior to the addition of DNA. Cleavage
complexes formed in the presence of the compound were stable for at
least 8 h. Lastly, black seed extract and black seed oil both increased
levels of enzyme-mediated DNA cleavage, suggesting that thymoquinone
is active even in more complex herbal formulations. These findings
indicate that thymoquinone can be added to the growing list of dietary
and medicinal natural products with activity against human type II
topoisomerases.
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Affiliation(s)
- Rachel E Ashley
- Departments of †Biochemistry and ‡Medicine (Hematology/Oncology), Vanderbilt University School of Medicine , Nashville, Tennessee 37232-0146, United States
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38
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Ketron AC, Osheroff N. Phytochemicals as Anticancer and Chemopreventive Topoisomerase II Poisons. PHYTOCHEMISTRY REVIEWS : PROCEEDINGS OF THE PHYTOCHEMICAL SOCIETY OF EUROPE 2014; 13:19-35. [PMID: 24678287 PMCID: PMC3963363 DOI: 10.1007/s11101-013-9291-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Phytochemicals are a rich source of anticancer drugs and chemopreventive agents. Several of these chemicals appear to exert at least some of their effects through interactions with topoisomerase II, an essential enzyme that regulates DNA supercoiling and removes knots and tangles from the genome. Topoisomerase II-active phytochemicals function by stabilizing covalent protein-cleaved DNA complexes that are intermediates in the catalytic cycle of the enzyme. As a result, these compounds convert topoisomerase II to a cellular toxin that fragments the genome. Because of their mode of action, they are referred to as topoisomerase II poisons as opposed to catalytic inhibitors. The first sections of this article discuss DNA topology, the catalytic cycle of topoisomerase II, and the two mechanisms (interfacial vs. covalent) by which different classes of topoisomerase II poisons alter enzyme activity. Subsequent sections discuss the effects of several phytochemicals on the type II enzyme, including demethyl-epipodophyllotoxins (semisynthetic anticancer drugs) as well as flavones, flavonols, isoflavones, catechins, isothiocyanates, and curcumin (dietary chemopreventive agents). Finally, the leukemogenic potential of topoisomerase II-targeted phytochemicals is described.
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Affiliation(s)
- Adam C. Ketron
- Department of Biochemistry and the Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 USA
| | - Neil Osheroff
- Departments of Biochemistry and Medicine (Hematology/Oncology) and the Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 USA
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39
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Pendleton M, Lindsey RH, Felix CA, Grimwade D, Osheroff N. Topoisomerase II and leukemia. Ann N Y Acad Sci 2014; 1310:98-110. [PMID: 24495080 DOI: 10.1111/nyas.12358] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Type II topoisomerases are essential enzymes that modulate DNA under- and overwinding, knotting, and tangling. Beyond their critical physiological functions, these enzymes are the targets for some of the most widely prescribed anticancer drugs (topoisomerase II poisons) in clinical use. Topoisomerase II poisons kill cells by increasing levels of covalent enzyme-cleaved DNA complexes that are normal reaction intermediates. Drugs such as etoposide, doxorubicin, and mitoxantrone are frontline therapies for a variety of solid tumors and hematological malignancies. Unfortunately, their use also is associated with the development of specific leukemias. Regimens that include etoposide or doxorubicin are linked to the occurrence of acute myeloid leukemias that feature rearrangements at chromosomal band 11q23. Similar rearrangements are seen in infant leukemias and are associated with gestational diets that are high in naturally occurring topoisomerase II-active compounds. Finally, regimens that include mitoxantrone and epirubicin are linked to acute promyelocytic leukemias that feature t(15;17) rearrangements. The first part of this article will focus on type II topoisomerases and describe the mechanism of enzyme and drug action. The second part will discuss how topoisomerase II poisons trigger chromosomal breaks that lead to leukemia and potential approaches for dissociating the actions of drugs from their leukemogenic potential.
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Affiliation(s)
- Maryjean Pendleton
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee
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40
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Jacob DA, Gibson EG, Mercer SL, Deweese JE. Etoposide catechol is an oxidizable topoisomerase II poison. Chem Res Toxicol 2013; 26:1156-8. [PMID: 23863110 DOI: 10.1021/tx400205n] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Topoisomerase II regulates DNA topology by generating transient double-stranded breaks. The anticancer drug etoposide targets topoisomerase II and is associated with the formation of secondary leukemias in patients. The quinone and catechol metabolites of etoposide may contribute to strand breaks that trigger leukemic translocations. To further analyze the characteristics of etoposide metabolites, we extend our previous analysis of etoposide quinone to the catechol. We demonstrate that the catechol is ∼2-3-fold more potent than etoposide and under oxidative reaction conditions induces high levels of double-stranded DNA cleavage. These results support a role for etoposide catechol in contributing to therapy-induced DNA damage.
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Affiliation(s)
- David A Jacob
- Department of Pharmaceutical Sciences, Lipscomb University College of Pharmacy and Health Sciences, Nashville, Tennessee 37204-3951, USA
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41
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Timmel MA, Byl JAW, Osheroff N. Epimerization of green tea catechins during brewing does not affect the ability to poison human type II topoisomerases. Chem Res Toxicol 2013; 26:622-8. [PMID: 23514406 DOI: 10.1021/tx4000667] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
(-)-Epigallocatechin gallate (EGCG) is the most abundant and biologically active polyphenol in green tea (Camellia sinensis) leaves, and many of its cellular effects are consistent with its actions as a topoisomerase II poison. In contrast to genistein and several related bioflavonoids that act as interfacial poisons, EGCG was the first bioflavonoid shown to act as a covalent topoisomerase II poison. Although studies routinely examine the effects of dietary phytochemicals on enzyme and cellular systems, they often fail to consider that many compounds are altered during cooking or cellular metabolism. To this point, the majority of EGCG and related catechins in green tea leaves are epimerized during the brewing process. Epimerization inverts the stereochemistry of the bond that bridges the B- and C-rings and converts EGCG to (-)-gallocatechin gallate (GCG). Consequently, a significant proportion of EGCG that is ingested during the consumption of green tea is actually GCG. Therefore, the effects of GCG and related epimerized green tea catechins on human topoisomerase IIα and IIβ were characterized. GCG increased levels of DNA cleavage mediated by both enzyme isoforms with an activity that was similar to that of EGCG. GCG acted primarily by inhibiting the ability of topoisomerase IIα and IIβ to ligate cleaved DNA. Several lines of evidence indicate that GCG functions as a covalent topoisomerase II poison that adducts the enzyme. Finally, epimerization did not affect the reactivity of the chemical substituents (the three hydroxyl groups on the B-ring) that were required for enzyme poisoning. Thus, the activity of covalent topoisomerase II poisons appears to be less sensitive to stereochemical changes than interfacial poisons.
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Affiliation(s)
- M Anne Timmel
- Departments of †Biochemistry and ‡Medicine (Hematology/Oncology), Vanderbilt University School of Medicine , Nashville, Tennessee 37232-0146, United States
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42
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Karkare S, Chung TTH, Collin F, Mitchenall LA, McKay AR, Greive SJ, Meyer JJM, Lall N, Maxwell A. The naphthoquinone diospyrin is an inhibitor of DNA gyrase with a novel mechanism of action. J Biol Chem 2012; 288:5149-56. [PMID: 23275348 PMCID: PMC3576119 DOI: 10.1074/jbc.m112.419069] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Tuberculosis and other bacterial diseases represent a significant threat to human health. The DNA topoisomerases are excellent targets for chemotherapy, and DNA gyrase in particular is a well-validated target for antibacterial agents. Naphthoquinones (e.g. diospyrin and 7-methyljuglone) have been shown to have therapeutic potential, particularly against Mycobacterium tuberculosis. We have found that these compounds are inhibitors of the supercoiling reaction catalyzed by M. tuberculosis gyrase and other gyrases. Our evidence strongly suggests that the compounds bind to the N-terminal domain of GyrB, which contains the ATPase active site, but are not competitive inhibitors of the ATPase reaction. We propose that naphthoquinones bind to GyrB at a novel site close to the ATPase site. This novel mode of action could be exploited to develop new antibacterial agents.
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Affiliation(s)
- Shantanu Karkare
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
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43
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Ketron AC, Gordon ON, Schneider C, Osheroff N. Oxidative metabolites of curcumin poison human type II topoisomerases. Biochemistry 2012; 52:221-7. [PMID: 23253398 DOI: 10.1021/bi3014455] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The polyphenol curcumin is the principal flavor and color component of the spice turmeric. Beyond its culinary uses, curcumin is believed to positively impact human health and displays antioxidant, anti-inflammatory, antibacterial, and chemopreventive properties. It also is in clinical trials as an anticancer agent. In aqueous solution at physiological pH, curcumin undergoes spontaneous autoxidation that is enhanced by oxidizing agents. The reaction proceeds through a series of quinone methide and other reactive intermediates to form a final dioxygenated bicyclopentadione product. Several naturally occurring polyphenols that can form quinones have been shown to act as topoisomerase II poisons (i.e., they increase levels of topoisomerase II-mediated DNA cleavage). Because several of these compounds have chemopreventive properties, we determined the effects of curcumin, its oxidative metabolites, and structurally related degradation products (vanillin, ferulic acid, and feruloylmethane) on the DNA cleavage activities of human topoisomerase IIα and IIβ. Intermediates in the curcumin oxidation pathway increased the level of DNA scission mediated by both enzymes ~4-5-fold. In contrast, curcumin and the bicyclopentadione, as well as vanillin, ferulic acid, and feruloylmethane, had no effect on DNA cleavage. As found for other quinone-based compounds, curcumin oxidation intermediates acted as redox-dependent (as opposed to interfacial) topoisomerase II poisons. Finally, under conditions that promote oxidation, the dietary spice turmeric enhanced topoisomerase II-mediated DNA cleavage. Thus, even within the more complex spice formulation, oxidized curcumin intermediates appear to function as topoisomerase II poisons.
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Affiliation(s)
- Adam C Ketron
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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44
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Siew EL, Chan KM, Williams GT, Ross D, Inayat-Hussain SH. Protection of hydroquinone-induced apoptosis by downregulation of Fau is mediated by NQO1. Free Radic Biol Med 2012; 53:1616-24. [PMID: 22687461 DOI: 10.1016/j.freeradbiomed.2012.05.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 05/26/2012] [Accepted: 05/30/2012] [Indexed: 01/11/2023]
Abstract
The Fau gene (Finkel-Biskis-Reilly murine sarcoma virus (FBR-MuSV)-associated ubiquitously expressed gene) was identified as a potential tumor suppressor gene using a forward genetics approach. Downregulation of Fau by overexpression of its reverse sequence has been shown to inhibit apoptosis induced by DNA-damaging agents. To address a potential role of Fau in benzene toxicity, we investigated the apoptotic effects of hydroquinone (HQ), a major benzene metabolite, in W7.2 mouse thymoma cells transfected with either a plasmid construct expressing the antisense sequence of Fau (rfau) or the empty vector (pcDNA3.1) as a control. HQ induced apoptosis via increased production of reactive oxygen species and DNA damage, measured using dihydroethidine (HE) staining and alkaline Comet assay, respectively, in W7.2 pcDNA3.1 cells. In contrast, when Fau was downregulated by the antisense sequence in W7.2 rfau cells, HQ treatment did not cause DNA damage and oxidative stress and these cells were markedly more resistant to HQ-induced apoptosis. Further investigation revealed that there was an upregulation of NAD(P)H: quinone oxidoreductase 1 (NQO1), a detoxification enzyme for benzene-derived quinones, in W7.2 rfau cells. Compromising cellular NQO1 by use of a specific mechanism-based inhibitor (MAC 220) and NQO1 siRNA resensitized W7.2 rfau cells to HQ-induced apoptosis. Silencing of Fau in W7.2 wild-type cells resulted in increased levels of NQO1, confirming that downregulation of Fau results in NQO1 upregulation which protects against HQ-induced apoptosis.
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Affiliation(s)
- E L Siew
- Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
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45
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Benes P, Alexova P, Knopfova L, Spanova A, Smarda J. Redox state alters anti-cancer effects of wedelolactone. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2012; 53:515-524. [PMID: 22733624 DOI: 10.1002/em.21712] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 05/23/2012] [Indexed: 06/01/2023]
Abstract
Wedelolactone is one of the active plant polyphenolic compounds. Anti-tumor effects of this drug have been demonstrated recently. We have described that wedelolactone acts as catalytic inhibitor of DNA topoisomerase IIα. The aim of this study was to further characterize the mechanism of its anti-tumor effects. We showed that wedelolactone inhibits binding of DNA topoisomerase IIα to plasmid DNA and antagonizes formation of etoposide-induced DNA cleavage complex. The inhibition of topoisomerase IIα by wedelolactone is reversible by excess of the enzyme but not DNA. The in vitro inhibitory effect of wedelolactone on the topoisomerase IIα activity is redox-dependent as it diminished in the presence of reducing agents. Cytotoxicity of wedelolactone was partially inhibited by N-acetylcysteine and glutathione ethyl ester in breast cancer MDA-MB-231 and MDA-MB-468 cells while the inhibitory effect of catalase was observed only in the former cell line. Finally, we found that wedelolactone can be oxidized in the presence of copper ions resulting in DNA strand break and abasic site formation in vitro. However, wedelolactone induced neither DNA damage in MDA-MB-231 cells nor mutations in bacterial cells detectable by Ames test suggesting that wedelolactone may not be an effective inducer of DNA damage. We conclude that the topoisomerase IIα inhibitory- and DNA damaging activities of wedelolactone in vitro depend on its redox state. Pro-oxidant activity could, however, explain only part of wedelolactone-induced cytotoxicity. Therefore, the major cellular target(s) of wedelolactone and the exact mechanism of wedelolactone-induced cytotoxicity still remain to be identified.
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Affiliation(s)
- Petr Benes
- Department of Experimental Biology, Masaryk University, Czech Republic.
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46
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Fronza M, Lamy E, Günther S, Heinzmann B, Laufer S, Merfort I. Abietane diterpenes induce cytotoxic effects in human pancreatic cancer cell line MIA PaCa-2 through different modes of action. PHYTOCHEMISTRY 2012; 78:107-119. [PMID: 22436445 DOI: 10.1016/j.phytochem.2012.02.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 02/10/2012] [Accepted: 02/21/2012] [Indexed: 05/27/2023]
Abstract
Abietane diterpenes, especially those containing quinone moieties, are often reported to have cytotoxic effects on cancer cell lines. They deserve greater attention because several cancer chemotherapeutic agents also possess the quinone structural feature. To date, very little is known about their cytotoxic molecular modes of action. In the present study, five diterpenes, 7 alpha-acetoxyroyleanone, horminone, royleanone, 7-ketoroyleanone and sugiol which have been previously isolated from the medicinal plant Peltodon longipes were shown to possess cytotoxic activity against the human pancreatic cancer cell line MIA PaCa-2. 7 alpha-Acetoxyroyleanone, horminone and royleanone were demonstrated to possess alkylating properties using the nucleophile 4-(4-nitrobenzyl)pyridine. However, no clear correlation between the alkylating properties and cytotoxicity of these diterpenes was observed. Furthermore, the relaxation activity of human DNA topoisomerases I and II was found to be influenced by these compounds, with 7-ketoroyleanone and sugiol being the most active. These two diterpenes preferentially inhibited topoisomerase I and exhibited lower IC(50) values than the classical topoisomerase I inhibitor camptothecin. Molecular docking studies revealed possible interactions of diterpenes with topoisomerase I, indicating that these compounds do not form the drug-enzyme-DNA covalent ternary complex as observed with camptothecin. A binding pocket located at the surface of the DNA-interaction site was proposed. Moreover, the ability of the five diterpenes to generate DNA-strand breaks in single cells was confirmed using the alkaline comet assay. As expected, these diterpenes also influenced cell cycle progression and arrested cells in different phases of the cell cycle, primarily the G1/G0 and S-phases. Interestingly, the diterpenes only exhibited a slight ability to induce apoptotic cell death and failed to generate intracellular reactive oxygen species. These results provide additional understanding of the cytotoxic effects of abietane diterpenes. Depending on their functional groups, we propose that abietane diterpenes utilise different mechanisms to induce cell death.
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Affiliation(s)
- Marcio Fronza
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, 79104 Freiburg, Germany
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47
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Lee CL, Lin YT, Chang FR, Chen GY, Backlund A, Yang JC, Chen SL, Wu YC. Synthesis and biological evaluation of phenanthrenes as cytotoxic agents with pharmacophore modeling and ChemGPS-NP prediction as topo II inhibitors. PLoS One 2012; 7:e37897. [PMID: 22666407 PMCID: PMC3362575 DOI: 10.1371/journal.pone.0037897] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 04/28/2012] [Indexed: 11/23/2022] Open
Abstract
In a structure-activity relationship (SAR) study, 3-methoxy-1,4-phenanthrenequinones, calanquinone A (6a), denbinobin (6b), 5-OAc-calanquinone A (7a) and 5-OAc-denbinobin (7b), have significantly promising cytotoxicity against various human cancer cell lines (IC50 0.08–1.66 µg/mL). Moreover, we also established a superior pharmacophore model for cytotoxicity (r = 0.931) containing three hydrogen bond acceptors (HBA1, HBA2 and HBA3) and one hydrophobic feature (HYD) against MCF-7 breast cancer cell line. The pharmacophore model indicates that HBA3 is an essential feature for the oxygen atom of 5-OH in 6a–b and for the carbonyl group of 5-OCOCH3 in 7a–b, important for their cytotoxic properties. The SAR for moderately active 5a–b (5-OCH3), and highly active 6a–b and 7a–b, are also elaborated in a spatial aspect model. Further rational design and synthesis of new cytotoxic phenanthrene analogs can be implemented via this model. Additionally, employing a ChemGPS-NP based model for cytotoxicity mode of action (MOA) provides support for a preliminary classification of compounds 6a–b as topoisomerase II inhibitors.
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Affiliation(s)
- Chia-Lin Lee
- School of Chinese Medicine, China Medical University, Taichung, Taiwan
- Natural Medicinal Products Research Center, China Medical University Hospital, Taichung, Taiwan
| | - Ying-Ting Lin
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Fang-Rong Chang
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
- Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
- * E-mail: (YCW); (FRC)
| | - Guan-Yu Chen
- Natural Medicinal Products Research Center, China Medical University Hospital, Taichung, Taiwan
| | - Anders Backlund
- Division of Pharmacognosy, Department of Medicinal Chemistry, BMC, Uppsala University, Uppsala, Sweden
| | - Juan-Chang Yang
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shu-Li Chen
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yang-Chang Wu
- School of Chinese Medicine, China Medical University, Taichung, Taiwan
- Natural Medicinal Products Research Center, China Medical University Hospital, Taichung, Taiwan
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan
- Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan
- * E-mail: (YCW); (FRC)
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48
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Auzanneau C, Montaudon D, Jacquet R, Puyo S, Pouységu L, Deffieux D, Elkaoukabi-Chaibi A, De Giorgi F, Ichas F, Quideau S, Pourquier P. The polyphenolic ellagitannin vescalagin acts as a preferential catalytic inhibitor of the α isoform of human DNA topoisomerase II. Mol Pharmacol 2012; 82:134-41. [PMID: 22528119 DOI: 10.1124/mol.111.077537] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Polyphenolic ellagitannins are natural compounds that are often associated with the therapeutic activity of plant extracts used in traditional medicine. They display cancer-preventing activity in animal models by a mechanism that remains unclear. Potential targets have been proposed, including DNA topoisomerases II (Top2). Top2α and Top2β, the two isoforms of the human Top2, play a crucial role in the regulation of replication, transcription, and chromosome segregation. They are the target of anticancer agents used in the clinic such as anthracyclines (e.g., doxorubicin) or the epipodophyllotoxin etoposide. It was recently shown that the antitumor activity of etoposide was due primarily to the inhibition of Top2α, whereas inhibition of Top2β was responsible for the development of secondary malignancies, pointing to the need for more selective Top2α inhibitors. Here, we show that the polyphenolic ellagitannin vescalagin preferentially inhibits the decatenation activity of Top2α in vitro, by a redox-independent mechanism. In CEM cells, we also show that transient small interfering RNA-mediated down-regulation of Top2α but not of Top2β conferred a resistance to vescalagin, indicating that the α isoform is a preferential target. We further confirmed that Top2α inhibition was due to a catalytic inhibition of the enzyme because it did not induce DNA double-strand breaks in CEM-treated cells but prevented the formation of Top2α- rather than Top2β-DNA covalent complexes induced by etoposide. To our knowledge, vescalagin is the first example of a catalytic inhibitor for which cytotoxicity is due, at least in part, to the preferential inhibition of Top2α.
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Affiliation(s)
- Céline Auzanneau
- Institut National de la Santé et de la Recherche Médicale U916 and Université de Bordeaux, Institut Bergonié, Bordeaux, France
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McHale CM, Zhang L, Smith MT. Current understanding of the mechanism of benzene-induced leukemia in humans: implications for risk assessment. Carcinogenesis 2012; 33:240-52. [PMID: 22166497 PMCID: PMC3271273 DOI: 10.1093/carcin/bgr297] [Citation(s) in RCA: 205] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 11/21/2011] [Accepted: 12/07/2011] [Indexed: 01/01/2023] Open
Abstract
Benzene causes acute myeloid leukemia and probably other hematological malignancies. As benzene also causes hematotoxicity even in workers exposed to levels below the US permissible occupational exposure limit of 1 part per million, further assessment of the health risks associated with its exposure, particularly at low levels, is needed. Here, we describe the probable mechanism by which benzene induces leukemia involving the targeting of critical genes and pathways through the induction of genetic, chromosomal or epigenetic abnormalities and genomic instability, in a hematopoietic stem cell (HSC); stromal cell dysregulation; apoptosis of HSCs and stromal cells and altered proliferation and differentiation of HSCs. These effects modulated by benzene-induced oxidative stress, aryl hydrocarbon receptor dysregulation and reduced immunosurveillance, lead to the generation of leukemic stem cells and subsequent clonal evolution to leukemia. A mode of action (MOA) approach to the risk assessment of benzene was recently proposed. This approach is limited, however, by the challenges of defining a simple stochastic MOA of benzene-induced leukemogenesis and of identifying relevant and quantifiable parameters associated with potential key events. An alternative risk assessment approach is the application of toxicogenomics and systems biology in human populations, animals and in vitro models of the HSC stem cell niche, exposed to a range of levels of benzene. These approaches will inform our understanding of the mechanisms of benzene toxicity and identify additional biomarkers of exposure, early effect and susceptibility useful for risk assessment.
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Affiliation(s)
| | | | - Martyn T. Smith
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, CA 94720-7356, USA
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Gurbani D, Kukshal V, Laubenthal J, Kumar A, Pandey A, Tripathi S, Arora A, Jain SK, Ramachandran R, Anderson D, Dhawan A. Mechanism of inhibition of the ATPase domain of human topoisomerase IIα by 1,4-benzoquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, and 9,10-phenanthroquinone. Toxicol Sci 2012; 126:372-90. [PMID: 22218491 DOI: 10.1093/toxsci/kfr345] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The inhibition of human topoisomerase IIα (Hu-TopoIIα), a major enzyme involved in maintaining DNA topology, repair, and chromosome condensation/decondensation results in loss of genomic integrity. In the present study, the inhibition of ATPase domain of Hu-TopoIIα as a possible mechanism of genotoxicity of 1,4-benzoquinone (BQ), hydroquinone (HQ), naphthoquinone (1,2-NQ and 1,4-NQ), and 9,10-phenanthroquinone (9,10-PQ) was investigated. In silico modeling predicted that 1,4-BQ, 1,2-NQ, 1,4-NQ, and 9,10-PQ could interact with Ser-148, Ser-149, Asn-150, and Asn-91 residues of the ATPase domain of Hu-TopoIIα. Biochemical inhibition assays with the purified ATPase domain of Hu-TopoIIα revealed that 1,4-BQ is the most potent inhibitor followed by 1,4-NQ > 1,2-NQ > 9,10-PQ > HQ. Ligand-binding studies using isothermal titration calorimetry revealed that 1,4-BQ, HQ, 1,4-NQ, 1,2-NQ, and 9,10-PQ enter into four sequentially binding site models inside the domain. 1,4-BQ exhibited the strongest binding, followed by 1,4-NQ > 1,2-NQ > 9,10-PQ > HQ, as revealed by their average K(d) values. The cellular fate of such inhibition was further evidenced by an increase in the number of Hu-TopoIIα-DNA cleavage complexes in the human lung epithelial cells (BEAS-2B) using trapped in agarose DNA immunostaining (TARDIS) assay, which utilizes antibody specific for Hu-TopoIIα. Furthermore, the increase in γ-H2A.X levels quantitated by flow cytometry and visualized by immunofluorescence microscopy illustrated that accumulation of DNA double-strand breaks inside the cells can be attributed to the inhibition of Hu-TopoIIα. These findings collectively suggest that 1,4-BQ, 1,2-NQ, 1,4-NQ, and 9,10-PQ inhibit the ATPase domain and potentially result in Hu-TopoIIα-mediated clastogenic and leukemogenic events.
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Affiliation(s)
- Deepak Gurbani
- Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, Lucknow-226001, Uttar Pradesh, India
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