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Wie M, Khim K, Groehler IV A, Heo S, Woo J, Son K, Lee E, Ra J, Hong S, Schärer O, Choi J, Myung K. Alkylation of nucleobases by 2-chloro- N,N-diethylethanamine hydrochloride (CDEAH) sensitizes PARP1-deficient tumors. NAR Cancer 2023; 5:zcad042. [PMID: 37554969 PMCID: PMC10405566 DOI: 10.1093/narcan/zcad042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 06/16/2023] [Accepted: 07/26/2023] [Indexed: 08/10/2023] Open
Abstract
Targeting BRCA1- and BRCA2-deficient tumors through synthetic lethality using poly(ADP-ribose) polymerase inhibitors (PARPi) has emerged as a successful strategy for cancer therapy. PARPi monotherapy has shown excellent efficacy and safety profiles in clinical practice but is limited by the need for tumor genome mutations in BRCA or other homologous recombination genes as well as the rapid emergence of resistance. In this study, we identified 2-chloro-N,N-diethylethanamine hydrochloride (CDEAH) as a small molecule that selectively kills PARP1- and xeroderma pigmentosum A-deficient cells. CDEAH is a monofunctional alkylating agent that preferentially alkylates guanine nucleobases, forming DNA adducts that can be removed from DNA by either a PARP1-dependent base excision repair or nucleotide excision repair. Treatment of PARP1-deficient cells leads to the formation of strand breaks, an accumulation of cells in S phase and activation of the DNA damage response. Furthermore, CDEAH selectively inhibits PARP1-deficient xenograft tumor growth compared to isogenic PARP1-proficient tumors. Collectively, we report the discovery of an alkylating agent inducing DNA damage that requires PARP1 activity for repair and acts synergistically with PARPi.
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Affiliation(s)
- Minwoo Wie
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Keon Woo Khim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Arnold S Groehler IV
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Soomin Heo
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Junhyeok Woo
- Department of Chemistry, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Kook Son
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Eun A Lee
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Jae Sun Ra
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Sung You Hong
- Department of Chemistry, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Orlando D Schärer
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Jang Hyun Choi
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
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2
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Ifosfamide - History, efficacy, toxicity and encephalopathy. Pharmacol Ther 2023; 243:108366. [PMID: 36842616 DOI: 10.1016/j.pharmthera.2023.108366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 02/16/2023] [Accepted: 02/21/2023] [Indexed: 02/26/2023]
Abstract
In this review we trace the passage of fundamental ideas through 20th century cancer research that began with observations on mustard gas toxicity in World War I. The transmutation of these ideas across scientific and national boundaries, was channeled from chemical carcinogenesis labs in London via Yale and Chicago, then ultimately to the pharmaceutical industry in Bielefeld, Germany. These first efforts to checkmate cancer with chemicals led eventually to the creation of one of the most successful groups of cancer chemotherapeutic drugs, the oxazaphosphorines, first cyclophosphamide (CP) in 1958 and soon thereafter its isomer ifosfamide (IFO). The giant contributions of Professor Sir Alexander Haddow, Dr. Alfred Z. Gilman & Dr. Louis S. Goodman, Dr. George Gomori and Dr. Norbert Brock step by step led to this breakthrough in cancer chemotherapy. A developing understanding of the metabolic disposition of ifosfamide directed efforts to ameliorate its side-effects, in particular, ifosfamide-induced encephalopathy (IIE). This has resulted in several candidates for the encephalopathic metabolite, including 2-chloroacetaldehyde, 2-chloroacetic acid, acrolein, 3-hydroxypropionic acid and S-carboxymethyl-L-cysteine. The pros and cons for each of these, together with other IFO metabolites, are discussed in detail. It is concluded that IFO produces encephalopathy in susceptible patients, but CP does not, by a "perfect storm," involving all of these five metabolites. Methylene blue (MB) administration appears to be generally effective in the prevention and treatment of IIE, in all probability by the inhibition of monoamine oxidase in brain potentiating serotonin levels that modulate the effects of IFO on GABAergic and glutamatergic systems. This review represents the authors' analysis of a large body of published research.
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3
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Friedman HS. Meet the Editorial Board Member. CURRENT CANCER THERAPY REVIEWS 2021. [DOI: 10.2174/157339471703210824150229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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4
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Shilkin ES, Boldinova EO, Stolyarenko AD, Goncharova RI, Chuprov-Netochin RN, Smal MP, Makarova AV. Translesion DNA Synthesis and Reinitiation of DNA Synthesis in Chemotherapy Resistance. BIOCHEMISTRY (MOSCOW) 2021; 85:869-882. [PMID: 33045948 DOI: 10.1134/s0006297920080039] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Many chemotherapy drugs block tumor cell division by damaging DNA. DNA polymerases eta (Pol η), iota (Pol ι), kappa (Pol κ), REV1 of the Y-family and zeta (Pol ζ) of the B-family efficiently incorporate nucleotides opposite a number of DNA lesions during translesion DNA synthesis. Primase-polymerase PrimPol and the Pol α-primase complex reinitiate DNA synthesis downstream of the damaged sites using their DNA primase activity. These enzymes can decrease the efficacy of chemotherapy drugs, contribute to the survival of tumor cells and to the progression of malignant diseases. DNA polymerases are promising targets for increasing the effectiveness of chemotherapy, and mutations and polymorphisms in some DNA polymerases can serve as additional prognostic markers in a number of oncological disorders.
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Affiliation(s)
- E S Shilkin
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, 123182, Russia
| | - E O Boldinova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, 123182, Russia
| | - A D Stolyarenko
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, 123182, Russia
| | - R I Goncharova
- Institute of Genetics and Cytology, National Academy of Sciences of Belarus, Minsk, 220072, Republic of Belarus
| | - R N Chuprov-Netochin
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - M P Smal
- Institute of Genetics and Cytology, National Academy of Sciences of Belarus, Minsk, 220072, Republic of Belarus.
| | - A V Makarova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, 123182, Russia.
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5
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Wolfrum M, Schwarz RJ, Schwarz M, Kramer M, Richert C. Stabilizing DNA nanostructures through reversible disulfide crosslinking. NANOSCALE 2019; 11:14921-14928. [PMID: 31360975 DOI: 10.1039/c9nr05143k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Designed DNA nanostructures can be generated in a wide range of sizes and shapes and have the potential to become exciting tools in material sciences, catalysis and medicine. However, DNA nanostructures are thermally labile assemblies of delicate biomacromolecules, and the lability hampers the use in many applications. Disulfide crosslinking is nature's successful approach to stabilize folded proteins against denaturation. It is therefore interesting to ask whether similar approaches can be used to stabilize DNA nanostructures. Here we report the synthesis of two 2'-deoxynucleoside phosphoramidites and two nucleosides linked to controlled pore glass that can be used to prepare oligodeoxynucleotides with protected thiol groups via automated DNA synthesis. Strands with one, two, three or four thiol-bearing nucleotides were prepared. One nicked duplex and three different nanostructures were assembled, the protected thiols were liberated under non-denaturing conditions, and disulfide crosslinking was induced with oxygen. Up to 19 crosslinks were thus placed in folded DNA structures up to 1456 nucleotides in size. The crosslinked structures had increased thermal stability, with UV-melting points 9-50 °C above that of the control structure. Disulfides were converted back to free thiols under reducing conditions. The redox-dependent increase in stability makes crosslinked DNA nanostructures attractive for the construction of responsive materials and biomedical applications.
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Affiliation(s)
- Manpreet Wolfrum
- Institute of Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany.
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6
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Kurinomaru T, Kojima N, Kurita R. Immobilization of DNA on Biosensing Devices with Nitrogen Mustard-Modified Linkers. ACTA ACUST UNITED AC 2019; 77:e85. [PMID: 31038292 DOI: 10.1002/cpnc.85] [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] [Indexed: 11/10/2022]
Abstract
Immobilization of DNA is an important step in relation to DNA-based biosensors and bioassays with multiple applications. This unit describes synthesis and applications of novel bifunctional linker molecules containing nitrogen mustard and one of two types of functional groups: cyclic disulfide or biotin. Two ways of immobilizing DNA on a surface are described. With the first method, a bifunctional alkylating linker molecule is first reacted with the target DNA to form alkylated DNA and then immobilized on a specific surface. With the second method, the bifunctional alkylating linker molecule is first attached to the surface, and then the target DNA is immobilized through an alkylating reaction with a nitrogen mustard moiety. We have also achieved immunochemical detection and quantification of 5-methylcytosine in a target DNA immobilized by the above methods. The methods for immobilization of intact DNA using novel bifunctional linker molecules are applicable to a wide range of biological analysis techniques. © 2019 by John Wiley & Sons, Inc.
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Affiliation(s)
- Takaaki Kurinomaru
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Japan
| | - Naoshi Kojima
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST) and DAILAB/DAICENTER, Tsukuba, Japan
| | - Ryoji Kurita
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST) and DAILAB/DAICENTER, Tsukuba, Japan
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7
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Effect of Chemotherapeutics and Tocopherols on MCF-7 Breast Adenocarcinoma and KGN Ovarian Carcinoma Cell Lines In Vitro. BIOMED RESEARCH INTERNATIONAL 2019; 2019:6146972. [PMID: 30766885 PMCID: PMC6350544 DOI: 10.1155/2019/6146972] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 11/28/2018] [Accepted: 12/30/2018] [Indexed: 02/04/2023]
Abstract
The combination of doxorubicin and cyclophosphamide commonly used to treat breast cancer can cause premature ovarian failure and infertility. α-Tocopherol is a potent antioxidant whereas γ-tocopherol causes apoptosis in a variety of cancer models in vitro including breast cancer. We hypothesised that the combination of doxorubicin (Dox) and 4-hydroperoxycyclophosphamide (4-Cyc) would be more cytotoxic in vitro than each agent alone, and that α-tocopherol would reduce and γ-tocopherol would augment the cytotoxicity of the combined chemotherapeutics. Human MCF-7 breast cancer and KGN ovarian cells were exposed to Dox, 4-Cyc, combined Dox and 4-Cyc, α-tocopherol, γ-tocopherol, or a combination of Dox and 4-Cyc with α-tocopherol or γ–tocopherol. Cell viability was assessed using a crystal violet assay according to four schedules: 24h exposure, 24h exposure + 24h culture in medium, 24h exposure + 48h culture in medium, or 72h continuous exposure. Supernatants from each separate KGN culture experiment (n=3) were examined using an estradiol ELISA. Dox was cytotoxic to both MCF-7 and KGN cells, but 4-Cyc only killed MCF-7 cells. γ-Tocopherol significantly decreased MCF-7 but not KGN cell viability. The combined chemotherapeutics and γ-tocopherol were more cytotoxic to MCF-7 than KGN cells, and α-tocopherol reduced the cytotoxicity of the combined chemotherapeutics towards KGN ovarian cells, but not MCF-7 cells. The addition of both γ-tocopherol and α-tocopherol to the chemotherapeutic combination of Dox and cyclophosphamide has the potential to increase in vitro chemotherapeutic efficacy against breast cancer cells whilst decreasing cytotoxicity towards ovarian granulosa cells.
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8
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Tera M, Harati Taji Z, Luedtke NW. Intercalation‐enhanced “Click” Crosslinking of DNA. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201808054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Masayuki Tera
- Department of ChemistryUniversity of Zurich Winterthurerstrasse 190 8057 Zurich Switzerland
- Bioorganic Research InstituteSuntory Foundation for Life Sciences (SUNBOR) 8-1-1 Seikadai, Seika, Soraku Kyoto 619-0284 Japan
| | - Zahra Harati Taji
- Department of ChemistryUniversity of Zurich Winterthurerstrasse 190 8057 Zurich Switzerland
| | - Nathan W. Luedtke
- Department of ChemistryUniversity of Zurich Winterthurerstrasse 190 8057 Zurich Switzerland
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9
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Tera M, Harati Taji Z, Luedtke NW. Intercalation-enhanced "Click" Crosslinking of DNA. Angew Chem Int Ed Engl 2018; 57:15405-15409. [PMID: 30240107 DOI: 10.1002/anie.201808054] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 08/22/2018] [Indexed: 01/05/2023]
Abstract
DNA-DNA cross-linking agents constitute an important family of chemotherapeutics that non-specifically react with endogenous nucleophiles and therefore exhibit undesirable side effects. Here we report a cationic Sondheimer diyne derivative "DiMOC" that exhibits weak, reversible intercalation into duplex DNA (Kd =15 μm) where it undergoes tandem strain-promoted cross-linking of azide-containing DNA to give DNA-DNA interstrand crosslinks (ICLs) with an exceptionally high apparent rate constant kapp =2.1×105 m-1 s-1 . This represents a 21 000-fold rate enhancement as compared the reaction between DIMOC and 5-(azidomethyl)-2'-deoxyuridine (AmdU) nucleoside. As single agents, 5'-bispivaloyloxymethyl (POM)-AmdU and DiMOC exhibited low cytotoxicity, but highly toxic DNA-DNA ICLs were generated by metabolic incorporation of AmdU groups into cellular DNA, followed by treatment of the cells with DiMOC. These results provide the first examples of intercalation-enhanced bioorthogonal chemical reactions on DNA, and furthermore, the first strain-promoted double click (SPDC) reactions inside of living cells.
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Affiliation(s)
- Masayuki Tera
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Bioorganic Research Institute, Suntory Foundation for Life Sciences (SUNBOR), 8-1-1 Seikadai, Seika, Soraku, Kyoto, 619-0284, Japan
| | - Zahra Harati Taji
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Nathan W Luedtke
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
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10
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Krüger-Genge A, Steinbrecht S, Küpper JH, Lendlein A, Jung F. Evidence for cytostatic effect of cyclophosphamide on human vein endothelial cells in cancer therapy: Preliminary in vitro results. Clin Hemorheol Microcirc 2018; 69:267-276. [DOI: 10.3233/ch-189125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- A. Krüger-Genge
- Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Teltow, Germany
| | - S. Steinbrecht
- Institute of Biotechnology, Brandenburgische Technische Universität Cottbus-Senftenberg, Senftenberg, Germany
| | - J.-H. Küpper
- Institute of Biotechnology, Brandenburgische Technische Universität Cottbus-Senftenberg, Senftenberg, Germany
| | - A. Lendlein
- Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Teltow, Germany
| | - F. Jung
- Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Teltow, Germany
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11
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Kurinomaru T, Kojima N, Kurita R. An alkylating immobilization linker for immunochemical epigenetic assessment. Chem Commun (Camb) 2018; 53:8308-8311. [PMID: 28686257 DOI: 10.1039/c7cc02883k] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A bifunctional linker molecule containing nitrogen mustard and a cyclic disulfide group has been developed for the covalent immobilization of intact DNA, which allows quantitative analysis of epigenomic modification in immobilized DNA using SPR-based immune sensing.
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Affiliation(s)
- Takaaki Kurinomaru
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST) and DAILAB, Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.
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12
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Brianese RC, Nakamura KDDM, Almeida FGDSR, Ramalho RF, Barros BDDF, Ferreira ENE, Formiga MNDC, de Andrade VP, de Lima VCC, Carraro DM. BRCA1 deficiency is a recurrent event in early-onset triple-negative breast cancer: a comprehensive analysis of germline mutations and somatic promoter methylation. Breast Cancer Res Treat 2017; 167:803-814. [DOI: 10.1007/s10549-017-4552-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 10/24/2017] [Indexed: 01/01/2023]
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13
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Nejad MI, Johnson KM, Price NE, Gates KS. A New Cross-Link for an Old Cross-Linking Drug: The Nitrogen Mustard Anticancer Agent Mechlorethamine Generates Cross-Links Derived from Abasic Sites in Addition to the Expected Drug-Bridged Cross-Links. Biochemistry 2016; 55:7033-7041. [PMID: 27992994 DOI: 10.1021/acs.biochem.6b01080] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nitrogen mustard anticancer drugs generate highly reactive aziridinium ions that alkylate DNA. Monoadducts arising from reaction with position N7 of guanine residues are the major DNA adducts generated by these agents. Interstrand cross-links in which the drug bridges position N7 of two guanine residues are formed in low yields relative to those of the monoadducts but are generally thought to be central to medicinal activity. The N7-alkylguanine residues generated by nitrogen mustards are depurinated to yield abasic (Ap) sites in duplex DNA. Here, we show that Ap sites generated by the nitrogen mustard mechlorethamine lead to interstrand cross-links of a type not previously associated with this drug. Gel electrophoretic data were consistent with early evolution of the expected drug-bridged cross-links, followed by the appearance of Ap-derived cross-links. The evidence is further consistent with a reaction pathway involving alkylation of a guanine residue in a 5'-GT sequence, followed by depurination to generate the Ap site, and cross-link formation via reaction of the Ap aldehyde residue with the opposing adenine residue at this site [Price, N. E., Johnson, K. M., Wang, J., Fekry, M. I., Wang, Y., and Gates, K. S. (2014) J. Am. Chem. Soc. 136, 3483-3490]. The monofunctional DNA-alkylating agents 2-chloro-N,N-diethylethanamine 5, (2-chloroethyl)ethylsulfide 6, and natural product leinamycin similarly were found to induce the formation of Ap-derived cross-links in duplex DNA. This work provides the first characterization of Ap-derived cross-links at sequences in which a cytosine residue is located directly opposing the Ap site. Cross-linking processes of this type could be relevant in medicine and biology because Ap sites with directly opposing cytosine residues occur frequently in genomic DNA via spontaneous or enzymatic depurination of guanine and N7-alkylguanine residues.
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Affiliation(s)
- Maryam Imani Nejad
- Department of Chemistry, University of Missouri , 125 Chemistry Building, Columbia, Missouri 65211, United States
| | - Kevin M Johnson
- Department of Chemistry, University of Missouri , 125 Chemistry Building, Columbia, Missouri 65211, United States
| | - Nathan E Price
- Department of Chemistry, University of Missouri , 125 Chemistry Building, Columbia, Missouri 65211, United States
| | - Kent S Gates
- Department of Chemistry, University of Missouri , 125 Chemistry Building, Columbia, Missouri 65211, United States.,Department of Biochemistry, University of Missouri , 125 Chemistry Building, Columbia, Missouri 65211, United States
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14
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Roy U, Mukherjee S, Sharma A, Frank EG, Schärer OD. The structure and duplex context of DNA interstrand crosslinks affects the activity of DNA polymerase η. Nucleic Acids Res 2016; 44:7281-91. [PMID: 27257072 PMCID: PMC5009737 DOI: 10.1093/nar/gkw485] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/20/2016] [Indexed: 12/18/2022] Open
Abstract
Several important anti-tumor agents form DNA interstrand crosslinks (ICLs), but their clinical efficiency is counteracted by multiple complex DNA repair pathways. All of these pathways require unhooking of the ICL from one strand of a DNA duplex by nucleases, followed by bypass of the unhooked ICL by translesion synthesis (TLS) polymerases. The structures of the unhooked ICLs remain unknown, yet the position of incisions and processing of the unhooked ICLs significantly influence the efficiency and fidelity of bypass by TLS polymerases. We have synthesized a panel of model unhooked nitrogen mustard ICLs to systematically investigate how the state of an unhooked ICL affects pol η activity. We find that duplex distortion induced by a crosslink plays a crucial role in translesion synthesis, and length of the duplex surrounding an unhooked ICL critically affects polymerase efficiency. We report the synthesis of a putative ICL repair intermediate that mimics the complete processing of an unhooked ICL to a single crosslinked nucleotide, and find that it provides only a minimal obstacle for DNA polymerases. Our results raise the possibility that, depending on the structure and extent of processing of an ICL, its bypass may not absolutely require TLS polymerases.
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Affiliation(s)
- Upasana Roy
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Shivam Mukherjee
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Anjali Sharma
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Ekaterina G Frank
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA
| | - Orlando D Schärer
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794-3400, USA
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15
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Zhao J, Zeng W, Cao Y, Liang X, Huang B. Immunotherapy of HPV infection-caused genital warts using low dose cyclophosphamide. Expert Rev Clin Immunol 2014; 10:791-9. [DOI: 10.1586/1744666x.2014.907743] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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16
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Mukherjee S, Guainazzi A, Schärer OD. Synthesis of structurally diverse major groove DNA interstrand crosslinks using three different aldehyde precursors. Nucleic Acids Res 2014; 42:7429-35. [PMID: 24782532 PMCID: PMC4066762 DOI: 10.1093/nar/gku328] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
DNA interstrand crosslinks (ICLs) are extremely cytotoxic lesions that block essential cellular processes, such as replication and transcription. Crosslinking agents are widely used in cancer chemotherapy and form an array of structurally diverse ICLs. Despite the clinical success of these agents, resistance of tumors to crosslinking agents, for example, through repair of these lesions by the cellular machinery remains a problem. We have previously reported the synthesis of site-specific ICLs mimicking those formed by nitrogen mustards to facilitate the studies of cellular responses to ICL formation. Here we extend these efforts and report the synthesis of structurally diverse major groove ICLs that induce severe, little or no distortion in the DNA. Our approach employs the incorporation of aldehyde precursors of different lengths into complementary strands and ICL formation using a double reductive amination with a variety of amines. Our studies provide insight into the structure and reactivity parameters of ICL formation by double reductive amination and yield a set of diverse ICLs that will be invaluable for exploring structure–activity relationships in ICL repair.
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Affiliation(s)
- Shivam Mukherjee
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Angelo Guainazzi
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794-8651, USA
| | - Orlando D Schärer
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794-8651, USA
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17
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Bhalli JA, Shaddock JG, Pearce MG, Dobrovolsky VN. Sensitivity of the Pig-a assay for detecting gene mutation in rats exposed acutely to strong clastogens. Mutagenesis 2013; 28:447-55. [PMID: 23677247 DOI: 10.1093/mutage/get022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Clastogens are potential human carcinogens whose detection by genotoxicity assays is important for safety assessment. Although some endogenous genes are sensitive to the mutagenicity of clastogens, many genes that are used as reporters for in vivo mutation (e.g. transgenes) are not. In this study, we have compared responses in the erythrocyte Pig-a gene mutation assay with responses in a gene mutation assay that is relatively sensitive to clastogens, the lymphocyte Hprt assay, and in the reticulocyte micronucleus (MN) assay, which provides a direct measurement of clastogenicity. Male F344 rats were treated acutely with X-rays, cyclophosphamide (CP) and Cis-platin (Cis-Pt), and the frequency of micronucleated reticulocytes (MN RETs) in peripheral blood was measured 1 or 2 days later. The frequencies of CD59-deficient Pig-a mutant erythrocytes and 6-thioguanine-resistant Hprt mutant T-lymphocytes were measured at several times up to 16 weeks after the exposure. All three clastogens induced strong increases in the frequency of MN RETs, with X-rays and Cis-Pt producing near linear dose responses. The three agents also were positive in the two gene mutation assays although the assays detected them with different efficiencies. The Pig-a assay was more efficient in detecting the effect of Cis-Pt treatment, whereas the Hprt assay was more efficient for X-rays and CP. The results indicate that the erythrocyte Pig-a assay can detect the in vivo mutagenicity of clastogens although its sensitivity is variable in comparison with the lymphocyte Hprt assay.
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Affiliation(s)
- Javed A Bhalli
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Road, HFT-120, Jefferson, AR 72079, USA
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Evaluation of the Bronchorelaxant, Genotoxic, and Antigenotoxic Effects of Cassia alata L. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:162651. [PMID: 23710211 PMCID: PMC3655621 DOI: 10.1155/2013/162651] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 02/18/2013] [Accepted: 03/12/2013] [Indexed: 11/17/2022]
Abstract
Aqueous-ethanolic extract of Cassia alata (AECal) and its derived fractions obtained through liquid-liquid fractionation were evaluated for their bronchorelaxant, genotoxic, and antigenotoxic effects. Contractile activity of rats' tracheas in the presence of tested materials, as well as its modifications with different inhibitors and blockers, was isometrically recorded. The antigenotoxic potential of AECal was evaluated on cyclophosphamide- (CP-) induced genotoxicity in the rat. Animals were pretreated with the extract, then liver comet assay was performed. AECal and its chloroformic fractions (CF-AECal) relaxed the contraction induced by Ach, but both were significantly less potent in inhibiting contraction induced by KCl (30 mM; 80 mM). Propranolol, indomethacin, L-NAME, methylene blue, and glibenclamide did not modify the relaxant effect of CF-AECal. TEA altered the response of trachea to CF-AECal. CF-AECal caused a rightward shift without affecting the E max in cumulative concentration-response curves of Ach only at low concentrations. In animals pretreated with the extract, the percentage of CP-induced DNA damage decreased. Our results suggest that (1) muscarinic receptors contribute at least in part to the relaxant effects of CF-AECal; (2) CF-AECal interferes with membrane polarization; and (3) AECal is not genotoxic in vivo and contains chemopreventive phytoconstituents offering protection against CP-induced genotoxicity.
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Qian L, Xiang D, Zhang J, Zhu S, Gao J, Wang X, Gao J, Zhang Y, Shen J, Yu Y, Han W, Wu M. Recombinant human interleukin-1 receptor antagonist reduces acute lethal toxicity and protects hematopoiesis from chemotoxicity in vivo. Biomed Pharmacother 2012; 67:108-15. [PMID: 23433850 DOI: 10.1016/j.biopha.2012.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 11/04/2012] [Indexed: 11/29/2022] Open
Abstract
Cyclophosphamide (CY), targeting to fast dividing cells, results in bone marrow (BM) suppression, which is the most common side effect of cancer chemotherapy. Interleukin-1 receptor antagonist (IL-1Ra), activated by variety of chemotherapeutic drugs, is a natural inhibitor of interleukin-1 (IL-1) and blocks the functional IL-1 receptor signaling. Our previous studies showed the protective effect of recombinant murine IL-1Ra on hematopoiesis in mice after treatment with chemotherapeutic agent 5-fluorouracil. In this report, we demonstrate that the pretreatment use of recombinant human IL-1Ra (rhIL-1Ra) significantly alleviated chemotherapy-induced peripheral blood injury in mice, and reduced the incidence and severity of neutropenia in beagle dogs. Moreover, acute lethal toxicity in single and repeated CY treatment was markedly reduced by rhIL-1Ra administration. The chemoprotective role of rhIL-1Ra is attributed to the attenuated BM damage, accelerated recovery of BM cells, and enhanced survival of hematopoietic progenitor cells which expressed high level of aldehyde dehydrogenase and IL-1 receptor type I. Thus, our data strongly suggest that the prophylactic use of exogenous rhIL-1Ra renders BM primitive hematopoietic cells resistant to chemotherapy, which provides novel strategies to prevent BM suppression in clinical settings.
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Affiliation(s)
- Lan Qian
- Laboratory of Regeneromics, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
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Polavarapu A, Stillabower JA, Stubblefield SGW, Taylor WM, Baik MH. The mechanism of guanine alkylation by nitrogen mustards: a computational study. J Org Chem 2012; 77:5914-21. [PMID: 22681226 DOI: 10.1021/jo300351g] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The thermodynamics and kinetics for the monofunctional binding of nitrogen mustard class of anticancer drugs to purine bases of DNA were studied computationally using guanine and adenine as model substrates. Mechlorethamine and melphalan are used as model systems in order to better understand the difference in antitumor activity of aliphatic and aromatic mustards, respectively. In good agreement with experiments that suggested the accumulation of a reactive intermediate in the case of mechlorethamine, our model predicts a significant preference for the formation of corresponding aziridinium ion for mechlorethamine, while the formation of the aziridinium ion is not computed to be preferred when melphalan is used. Two effects are found that contribute to this difference. First, the ground state of the drug shows a highly delocalized lone pair on the amine nitrogen of the melphalan, which makes the subsequent cyclization more difficult. Second, because of the aromatic substituent connected to the amine nitrogen of melphalan, a large energy penalty has to be paid for solvation. A detailed study of energy profiles for the two-step mechanism for alkylation of guanine and adenine was performed. Alkylation of guanine is ∼6 kcal mol(-1) preferred over adenine, and the factors contributing to this preference were explained in our previous study of cisplatin binding to purine bases. A detailed analysis of energy profiles of mechlorethamine and melphalan binding to guanine and adenine are presented to provide an insight into rate limiting step and the difference in reactivity and stability of the intermediate in both nitrogen mustards, respectively.
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Affiliation(s)
- Abhigna Polavarapu
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405, USA
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Fassbender C, Braunbeck T, Keiter SH. Gene-TEQ--a standardized comparative assessment of effects in the comet assay using genotoxicity equivalents. JOURNAL OF ENVIRONMENTAL MONITORING : JEM 2012; 14:1325-1334. [PMID: 22441078 DOI: 10.1039/c2em10947f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Existing methods for the comparison of genotoxic effects in the comet assay bear considerable disadvantages such as the problem to link information about concentration dependence and severity of effects. Moreover, given the lack of standardized protocols and the use of various standards, it may be extremely difficult to compare different studies. In order to provide a method for standardized comparative assessment of genotoxic effects, the concept of genotoxicity equivalents (Gene-TEQ) was developed. As potential reference compounds for genotoxic effects, three directly acting (N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), methyl-methanesulfonate, and N-methyl-N-nitrosourea) and three indirectly acting (cyclophosphamide, dimethylnitrosamine, and 4-nitroquinoline-oxide) genotoxic substances were compared with respect to their cytotoxic (neutral red) and genotoxic (comet assay) concentration-response profiles in the permanent fish cell line RTL-W1. For further comparison, two sediment extracts from the upper Danube River were investigated as environmental samples. Based on the results of cytotoxicity and genotoxicity testing, MNNG was selected as the reference compound. At several exposure levels and durations, genotoxic effects of both the other pure substances and the environmental samples were calculated as percentages of the maximum MNNG effect and related to the absolute MNNG effect (EC values). Thus, genotoxicity equivalent factors (Gene-TEQs) relative to MNNG could be calculated. Gene-TEQs can easily be applied to pure substances, mixtures and field samples to provide information about their toxicity relative to the reference compound. Furthermore, the Gene-TEQ concept allows a direct comparison of environmental samples from different laboratories.
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Affiliation(s)
- Christopher Fassbender
- Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, D-69120 Heidelberg, Germany.
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McManus FP, O'Flaherty DK, Noronha AM, Wilds CJ. O4-Alkyl-2′-deoxythymidine cross-linked DNA to probe recognition and repair by O6-alkylguanine DNA alkyltransferases. Org Biomol Chem 2012; 10:7078-90. [DOI: 10.1039/c2ob25705j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Dobrovolsky VN, Elespuru RK, Bigger CAH, Robison TW, Heflich RH. Monitoring humans for somatic mutation in the endogenous PIG-a gene using red blood cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2011; 52:784-794. [PMID: 21826740 DOI: 10.1002/em.20667] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 06/03/2011] [Accepted: 06/08/2011] [Indexed: 05/31/2023]
Abstract
The endogenous X-linked PIG-A gene is involved in the synthesis of glycosyl phosphatidyl inositol (GPI) anchors that tether specific protein markers to the exterior of mammalian cell cytoplasmic membranes. Earlier studies in rodent models indicate that Pig-a mutant red blood cells (RBCs) can be induced in animals treated with genotoxic agents, and that flow cytometry can be used to identify rare RBCs deficient in the GPI-anchored protein, CD59, as a marker of Pig-a gene mutation. We investigated if a similar approach could be used for detecting gene mutation in humans. We first determined the frequency of spontaneous CD59-deficient RBCs (presumed PIG-A mutants) in 97 self-identified healthy volunteers. For most subjects, the frequency of CD59-deficient RBCs was low (average of 5.1 ± 4.9 × 10(-6) ; median of 3.8 × 10(-6) and mutant frequency less than 8 × 10(-6) for 75% of subjects), with a statistically significant difference in median mutant frequencies between males and females. PIG-A RBC mutant frequency displayed poor correlation with the age and no correlation with the smoking status of the subjects. Also, two individuals had markedly increased CD59-deficient RBC frequencies of ∼300 × 10(-6) and ∼100 × 10(-6) . We then monitored PIG-A mutation in 10 newly diagnosed cancer patients undergoing chemotherapy with known genotoxic drugs. The frequency of CD59-deficient RBCs in the blood of the patients was measured before the start of chemotherapy and three times over a period of ∼6 months while on/after chemotherapy. Responses were generally weak, most observations being less than the median mutant frequency for both males and females; the greatest response was an approximate three-fold increase in the frequency of CD59-deficient RBCs in one patient treated with a combination of cisplatin and etoposide. These results suggest that the RBC PIG-A assay can be adopted to measuring somatic cell mutation in humans. Further research is necessary to determine the assay's sensitivity in detecting mutations induced by genotoxic agents acting via different mechanisms.
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Affiliation(s)
- Vasily N Dobrovolsky
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US FDA, Jefferson, Arkansas, USA.
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Kuang Y, Balakrishnan K, Gandhi V, Peng X. Hydrogen peroxide inducible DNA cross-linking agents: targeted anticancer prodrugs. J Am Chem Soc 2011; 133:19278-81. [PMID: 22035519 DOI: 10.1021/ja2073824] [Citation(s) in RCA: 237] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The major concern for anticancer chemotherapeutic agents is the host toxicity. The development of anticancer prodrugs targeting the unique biochemical alterations in cancer cells is an attractive approach to achieve therapeutic activity and selectivity. We designed and synthesized a new type of nitrogen mustard prodrug that can be activated by high level of reactive oxygen species (ROS) found in cancer cells to release the active chemotherapy agent. The activation mechanism was determined by NMR analysis. The activity and selectivity of these prodrugs toward ROS was determined by measuring DNA interstrand cross-links and/or DNA alkylations. These compounds showed 60-90% inhibition toward various cancer cells, while normal lymphocytes were not affected. To the best of our knowledge, this is the first example of H(2)O(2)-activated anticancer prodrugs.
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Affiliation(s)
- Yunyan Kuang
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, USA
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25
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Cyclophosphamide-induced disruption of umami taste functions and taste epithelium. Neuroscience 2011; 192:732-45. [DOI: 10.1016/j.neuroscience.2011.07.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 07/03/2011] [Accepted: 07/06/2011] [Indexed: 11/18/2022]
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Chen N, Hanly L, Rieder M, Yeger H, Koren G. The effect of N-acetylcysteine on the antitumor activity of ifosfamide. Can J Physiol Pharmacol 2011; 89:335-43. [PMID: 21609276 DOI: 10.1139/y11-028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ifosfamide-induced nephrotoxicity is a serious adverse effect in children undergoing chemotherapy. Our previous cell and rodent models have shown that the antioxidant N-acetylcysteine (NAC), used extensively as an antidote for acetaminophen poisoning, protects renal tubular cells from ifosfamide-induced nephrotoxicity at a clinically relevant concentration. For the use of NAC to be clinically relevant in preventing ifosfamide nephrotoxicity, we must ensure there is no effect of NAC on the antitumor activity of ifosfamide. Common pediatric tumors that are sensitive to ifosfamide, human neuroblastoma SK-N-BE(2) and rhabdomyosarcoma RD114-B cells, received either no pretreatment or pretreatment with 400 µmol/L of NAC, followed by concurrent treatment with NAC and either ifosfamide or the active agent ifosfamide mustard. Ifosfamide mustard significantly decreased the growth of both cancer cell lines in a dose-dependent manner (p < 0.001). The different combined treatments of NAC alone, sodium 2-mercaptoethanesulfonate alone, or NAC plus sodium 2-mercaptoethanesulfonate did not significantly interfere with the tumor cytotoxic effect of ifosfamide mustard. These observations suggest that NAC may improve the risk/benefit ratio of ifosfamide by decreasing ifosfamide-induced nephrotoxicity without interfering with its antitumor effect in cancer cells clinically treated with ifosfamide.
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Affiliation(s)
- Nancy Chen
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Canada
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Sharma A, Shukla A, Mishra M, Chowdhuri DK. Validation and application of Drosophila melanogaster as an in vivo model for the detection of double strand breaks by neutral Comet assay. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 721:142-6. [DOI: 10.1016/j.mrgentox.2011.01.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 01/05/2011] [Accepted: 01/16/2011] [Indexed: 10/18/2022]
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Guainazzi A, Campbell AJ, Angelov T, Simmerling C, Schärer OD. Synthesis and molecular modeling of a nitrogen mustard DNA interstrand crosslink. Chemistry 2011; 16:12100-3. [PMID: 20842675 DOI: 10.1002/chem.201002041] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Angelo Guainazzi
- Department of Pharmacological Sciences and Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
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29
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Xiang D, Guo Y, Zhang J, Gao J, Lu H, Zhu S, Wu M, Yu Y, Han W. Interleukin-1 receptor antagonist attenuates cyclophosphamide-induced mucositis in a murine model. Cancer Chemother Pharmacol 2010; 67:1445-53. [DOI: 10.1007/s00280-010-1439-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 08/13/2010] [Indexed: 01/09/2023]
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Ozolins̆ TR. Cyclophosphamide and the Teratology society: an awkward marriage. ACTA ACUST UNITED AC 2010; 89:289-99. [DOI: 10.1002/bdrb.20255] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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31
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Malayappan B, Johnson L, Nie B, Panchal D, Matter B, Jacobson P, Tretyakova N. Quantitative high-performance liquid chromatography-electrospray ionization tandem mass spectrometry analysis of bis-N7-guanine DNA-DNA cross-links in white blood cells of cancer patients receiving cyclophosphamide therapy. Anal Chem 2010; 82:3650-8. [PMID: 20361772 DOI: 10.1021/ac902923s] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cyclophosphamide (CPA) is a DNA alkylating agent widely used in cancer chemotherapy. CPA undergoes metabolic activation to phosphoramide mustard and nornitrogen mustard (NOR) which alkylate the N-7 position of guanine in DNA to produce N-[2-(N7-guaninyl) ethyl]-N-[2-hydroxyethyl]-amine (G-NOR-OH) monoadducts and N,N-bis[2-(N7-guaninyl) ethyl] amine cross-links (G-NOR-G). G-NOR-G cross-links are strongly cytotoxic and are thought to be responsible for the biological activity of CPA. In the present work, an isotope dilution high-performance liquid chromatography-electrospray ionization (positive ion) tandem mass spectrometry (HPLC-ESI(+)-MS/MS) methodology was developed to accurately quantify G-NOR-G adducts in human blood. In our approach, DNA extracted from white blood cells (5-20 microg) is spiked with an internal standard of [(15)N(10)]-G-NOR-G and subjected to thermal hydrolysis to release G-NOR-G adducts from the DNA backbone. Following solid phase extraction, G-NOR-G conjugates are quantified by capillary HPLC-ESI-MS/MS in the selected reaction monitoring mode. The application of the new methodology is demonstrated for DNA extracted from blood of three cancer patients receiving 50-60 mg/kg of intravenous CPA. The highest numbers of G-NOR-G adduct (up to 18 adducts per 10(6) normal nucleotides) were observed 4-8 h following CPA administration, followed by a gradual decrease over time, probably due to adduct hydrolysis, DNA repair, and white blood cell death. This methodology will be useful for future investigations of the interindividual differences for CPA-induced DNA-DNA cross-linking.
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Affiliation(s)
- Bhaskar Malayappan
- Departments of Medicinal Chemistry, Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Abstract
Cyclophosphamide remains one of the most successful and widely utilized antineoplastic drugs. Moreover, it is also a potent immunosuppressive agent and the most commonly used drug in blood and marrow transplantation (BMT). It was initially synthesized to selectively target cancer cells, although the hypothesized mechanism of tumor specificity (activation by cancer cell phosphamidases) transpired to be irrelevant to its activity. Nevertheless, cyclophosphamide's unique metabolism and inactivation by aldehyde dehydrogenase is responsible for its distinct cytotoxic properties. Differential cellular expression of aldehyde dehydrogenase has an effect on the anticancer therapeutic index and immunosuppressive properties of cyclophosphamide. This Review highlights the chemistry, pharmacology, clinical toxic effects and current clinical applications of cyclophosphamide in cancer and autoimmune disorders. We also discuss the development of high-dose cyclophosphamide for BMT and the treatment of autoimmune diseases.
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Affiliation(s)
- Ashkan Emadi
- Division of Adult Hematology, Johns Hopkins University, Baltimore, MD, USA.
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Angelov T, Guainazzi A, Schärer OD. Generation of DNA interstrand cross-links by post-synthetic reductive amination. Org Lett 2009; 11:661-4. [PMID: 19132933 DOI: 10.1021/ol802719a] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DNA interstrand cross-links (ICLs) are the clinically most relevant adducts formed by many antitumor agents. To facilitate the study of biological responses triggered by ICLs, we developed a new approach toward the synthesis of mimics of nitrogen mustard ICLs. 7-Deazaguanine residues bearing acetaldehyde groups were incorporated into complementary strands of DNA and cross-link formation induced by double reductive amination. Our strategy enables the synthesis of major groove cross-links in high yields and purity.
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Affiliation(s)
- Todor Angelov
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Ho KK, Mukhopadhyay A, Li YF, Mukhopadhyay S, Weiner H. A point mutation produced a class 3 aldehyde dehydrogenase with increased protective ability against the killing effect of cyclophosphamide. Biochem Pharmacol 2008; 76:690-6. [PMID: 18647600 DOI: 10.1016/j.bcp.2008.06.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 06/24/2008] [Accepted: 06/24/2008] [Indexed: 11/28/2022]
Abstract
Cyclophosphamides are pro-drugs whose killing agent is produced from an aldehyde that is formed by the action of a P450 oxidation step. The mustard from the aldehyde can destroy bone marrow cells as well as the tumor. Aldehyde dehydrogenase (EC 1.2.1.3) can oxidize the aldehyde and hence inactivate the cytotoxic intermediate but bone marrow has little, if any, of the enzyme. Others have shown that over-expression of the enzyme can afford protection of the marrow. A T186S mutant of the human stomach enzyme (ALDH3) that we developed has increased activity against the aldehyde compared to the native enzyme and HeLa cells transformed with the point mutant are better protected against the killing effect of the drug. It took threefold more drug to kill 90% of the cells transformed with the mutant compared to the native enzyme (15.8 compared to 5.1mM of a precursor of the toxic aldehyde). Analysis of molecular models makes it appear that removing the methyl group of threonine in the T186S mutant allows the bulky aldehyde to bind better. The mutant was found to be a poorer enzyme when small substrates such as benzaldehyde derivatives were investigated. Thus, the enzyme appears to be better only with large substrates such as the one produced by cyclophosphamide.
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Affiliation(s)
- Kwok Ki Ho
- Department of Biochemistry, Purdue University, 175 S. University Street, West Lafayette, IN 47907-2063, United States
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Wang F, Li F, Ganguly M, Marky LA, Gold B, Egli M, Stone MP. A bridging water anchors the tethered 5-(3-aminopropyl)-2'-deoxyuridine amine in the DNA major groove proximate to the N+2 C.G base pair: implications for formation of interstrand 5'-GNC-3' cross-links by nitrogen mustards. Biochemistry 2008; 47:7147-57. [PMID: 18549246 DOI: 10.1021/bi800375m] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Site-specific insertion of 5-(3-aminopropyl)-2'-deoxyuridine (Z3dU) and 7-deaza-dG into the Dickerson-Drew dodecamers 5'-d(C (1)G (2)C (3)G (4)A (5)A (6)T (7)T (8)C (9) Z (10)C (11)G (12))-3'.5'-d(C (13)G (14)C (15)G (16)A (17)A (18)T (19)T (20)C (21) Z (22)C (23)G (24))-3' (named DDD (Z10)) and 5'-d(C (1)G (2)C (3)G (4)A (5)A (6)T (7) X (8)C (9) Z (10)C (11)G (12))-3'.5'-d(C (13)G (14)C (15)G (16)A (17)A (18)T (19) X (20)C (21) Z (22)C (23)G (24))-3' (named DDD (2+Z10)) (X = Z3dU; Z = 7-deaza-dG) suggests a mechanism underlying the formation of interstrand N+2 DNA cross-links by nitrogen mustards, e.g., melphalan and mechlorethamine. Analysis of the DDD (2+Z10) duplex reveals that the tethered cations at base pairs A (5).X (20) and X (8).A (17) extend within the major groove in the 3'-direction, toward conserved Mg (2+) binding sites located adjacent to N+2 base pairs C (3).Z (22) and Z (10).C (15). Bridging waters located between the tethered amines and either Z (10) or Z (22) O (6) stabilize the tethered cations and allow interactions with the N + 2 base pairs without DNA bending. Incorporation of 7-deaza-dG into the DDD (2+Z10) duplex weakens but does not eliminate electrostatic interactions between tethered amines and Z (10) O (6) and Z (22) O (6). The results suggest a mechanism by which tethered N7-dG aziridinium ions, the active species involved in formation of interstrand 5'-GNC-3' cross-links by nitrogen mustards, modify the electrostatics of the major groove and position the aziridinium ions proximate to the major groove edge of the N+2 C.G base pair, facilitating interstrand cross-linking.
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Affiliation(s)
- Feng Wang
- Department of Chemistry, Center in Molecular Toxicology, and Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, USA
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Shanmugara T, Arunsundar M, Somasundar I, Krishnakum E, Sivaraman D, Ravichandi V. Cardioprotective Effect of Ficus hispida Linn. on Cyclophosphamide Provoked Oxidative Myocardial Injury in a Rat Model. INT J PHARMACOL 2008. [DOI: 10.3923/ijp.2008.78.87] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Bodó E, Tobin DJ, Kamenisch Y, Bíró T, Berneburg M, Funk W, Paus R. Dissecting the impact of chemotherapy on the human hair follicle: a pragmatic in vitro assay for studying the pathogenesis and potential management of hair follicle dystrophy. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 171:1153-67. [PMID: 17823286 PMCID: PMC1988866 DOI: 10.2353/ajpath.2007.061164] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chemotherapy-induced alopecia represents one of the major unresolved problems of clinical oncology. The underlying molecular pathogenesis in humans is virtually unknown because of the lack of adequate research models. Therefore, we have explored whether microdissected, organ-cultured, human scalp hair follicles (HFs) in anagen VI can be exploited for dissecting and manipulating the impact of chemotherapy on human HFs. Here, we show that these organ-cultured HFs respond to a key cyclophosphamide metabolite, 4-hydroperoxycyclophosphamide (4-HC), in a manner that resembles chemotherapy-induced HF dystrophy as it occurs in vivo: namely, 4-HC induced melanin clumping and melanin incontinence, down-regulated keratinocyte proliferation, massively up-regulated apoptosis of hair matrix keratinocytes, prematurely induced catagen, and up-regulated p53. In addition, 4-HC induced DNA oxidation and the mitochondrial DNA common deletion. The organ culture system facilitated the identification of new molecular targets for chemotherapy-induced HF damage by microarray technology (eg, interleukin-8, fibroblast growth factor-18, and glypican 6). It was also used to explore candidate chemotherapy protectants, for which we used the cytoprotective cytokine keratinocyte growth factor as exemplary pilot agent. Thus, this novel system serves as a powerful yet pragmatic tool for dissecting and manipulating the impact of chemotherapy on the human HF.
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Affiliation(s)
- Eniko Bodó
- Department of Dermatology, University Hospital Schleswig-Holstein, University of Lübeck, D-23538 Lübeck, Ratzeburger Allee 160, Germany.
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Hansen RJ, Ludeman SM, Paikoff SJ, Pegg AE, Dolan ME. Role of MGMT in protecting against cyclophosphamide-induced toxicity in cells and animals. DNA Repair (Amst) 2007; 6:1145-54. [PMID: 17485251 PMCID: PMC1989758 DOI: 10.1016/j.dnarep.2007.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
O(6)-Methylguanine-DNA methyltransferase (MGMT) is a DNA repair protein that protects cells from the biological consequences of alkylating agents by removing alkyl groups from the O(6)-position of guanine. Cyclophosphamide and ifosfamide are oxazaphosphorines used clinically to treat a wide variety of cancers; however, the role of MGMT in recognizing DNA damage induced by these agents is unclear. In vitro evidence suggests that MGMT may protect against the urotoxic oxazaphosphorine metabolite, acrolein. Here, we demonstrate that Chinese hamster ovary cells transfected with MGMT are protected against cytotoxicity following treatment with chloroacetaldehyde (CAA), a neuro- and nephrotoxic metabolite of cyclophosphamide and ifosfamide. The mechanism by which MGMT recognizes damage induced by acrolein and CAA is unknown. CHO cells expressing a mutant form of MGMT (MGMT(R128A)), known to have >1000-fold less repair activity towards alkylated DNA while maintaining full active site transferase activity towards low molecular weight substrates, exhibited equivalent CAA- and acrolein-induced cytotoxicity to that of CHO cells transfected with plasmid control. These results imply that direct reaction of acrolein or CAA with the active site cysteine residue of MGMT, i.e. scavenging, is unlikely a mechanism to explain MGMT protection from CAA and acrolein-induced toxicity. In vivo, no difference was detected between Mgmt-/- and Mgmt+/+ mice in the lethal effects of cyclophosphamide. While MGMT may be important at the cellular level, mice deficient in MGMT are not significantly more susceptible to cyclophosphamide, acrolein or CAA. Thus, our data does not support targeting MGMT to improve oxazaphosphorine therapy.
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Affiliation(s)
- Ryan J. Hansen
- Committee on Cancer Biology, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637
| | - Susan M. Ludeman
- Duke Comprehensive Cancer Center and Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710
| | - Sari J. Paikoff
- Duke Comprehensive Cancer Center and Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710
| | - Anthony E. Pegg
- Departments of Cellular and Molecular Physiology and Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - M. Eileen Dolan
- Committee on Cancer Biology, Department of Medicine and Committee on Clinical Pharmacology and Pharmacogenomics, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637
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Patzer L, Hernando N, Ziegler U, Beck-Schimmer B, Biber J, Murer H. Ifosfamide metabolites CAA, 4-OH-Ifo and Ifo-mustard reduce apical phosphate transport by changing NaPi-IIa in OK cells. Kidney Int 2006; 70:1725-34. [PMID: 17003823 DOI: 10.1038/sj.ki.5001803] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Renal Fanconi syndrome occurs in about 1-5% of all children treated with Ifosfamide (Ifo) and impairment of renal phosphate reabsorption in about 20-30% of them. Pathophysiological mechanisms of Ifo-induced nephropathy are ill defined. The aim has been to investigate whether Ifo metabolites affect the type IIa sodium-dependent phosphate transporter (NaPi-IIa) in viable opossum kidney cells. Ifo did not influence viability of cells or NaPi-IIa-mediated transport up to 1 mM/24 h. Incubation of confluent cells with chloroacetaldehyde (CAA) and 4-hydroperoxyIfosfamide (4-OH-Ifo) led to cell death by necrosis in a concentration-dependent manner. At low concentrations (50-100 microM/24 h), cell viability was normal but apical phosphate transport, NaPi-IIa protein, and -mRNA expression were significantly reduced. Coincubation with sodium-2-mercaptoethanesulfonate (MESNA) prevented the inhibitory action of CAA but not of 4-OH-Ifo; DiMESNA had no effect. Incubation with Ifosfamide-mustard (Ifo-mustard) did alter cell viability at concentrations above 500 microM/24 h. At lower concentrations (50-100 microM/24 h), it led to significant reduction in phosphate transport, NaPi-IIa protein, and mRNA expression. MESNA did not block these effects. The effect of Ifo-mustard was due to internalization of NaPi-IIa. Cyclophosphamide-mustard (CyP-mustard) did not have any influence on cell survival up to 1000 microM, but the inhibitory effect on phosphate transport and on NaPi-IIa protein was the same as found after Ifo-mustard. In conclusion, CAA, 4-OH-Ifo, and Ifo- and CyP-mustard are able to inhibit sodium-dependent phosphate cotransport in viable opossum kidney cells. The Ifo-mustard effect took place via internalization and reduction of de novo synthesis of NaPi-IIa. Therefore, it is possible that Ifo-mustard plays an important role in pathogenesis of Ifo-induced nephropathy.
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Affiliation(s)
- L Patzer
- Department of Pediatrics, Friedrich-Schiller-University, Jena, Germany.
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Affiliation(s)
| | - Tracey McGregor Mason
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, Maryland 21205
| | - Paul S. Miller
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, Maryland 21205
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Ludeman SM, Gamcsik MP. Mechanisms of resistance against cyclophosphamide and ifosfamide: can they be overcome without sacrificing selectivity? Cancer Treat Res 2003; 112:177-97. [PMID: 12481717 DOI: 10.1007/978-1-4615-1173-1_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- Susan M Ludeman
- Duke Comprehensive Cancer Center, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
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DNA-alkylating events associated with nitrogen mustard based anticancer drugs and the metabolic byproduct Acrolein. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1067-568x(02)80004-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Kerbusch T, de Kraker J, Keizer HJ, van Putten JW, Groen HJ, Jansen RL, Schellens JH, Beijnen JH. Clinical pharmacokinetics and pharmacodynamics of ifosfamide and its metabolites. Clin Pharmacokinet 2001; 40:41-62. [PMID: 11236809 DOI: 10.2165/00003088-200140010-00004] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
This review discusses several issues in the clinical pharmacology of the antitumour agent ifosfamide and its metabolites. Ifosfamide is effective in a large number of malignant diseases. Its use, however, can be accompanied by haematological toxicity, neurotoxicity and nephrotoxicity. Since its development in the middle of the 1960s, most of the extensive metabolism of ifosfamide has been elucidated. Identification of specific isoenzymes responsible for ifosfamide metabolism may lead to an improved efficacy/toxicity ratio by modulation of the metabolic pathways. Whether ifosfamide is specifically transported by erythrocytes and which activated ifosfamide metabolites play a key role in this transport is currently being debated. In most clinical pharmacokinetic studies, the phenomenon of autoinduction has been observed, but the mechanism is not completely understood. Assessment of the pharmacokinetics of ifosfamide and metabolites has long been impaired by the lack of reliable bioanalytical assays. The recent development of improved bioanalytical assays has changed this dramatically, allowing extensive pharmacokinetic assessment, identifying key issues such as population differences in pharmacokinetic parameters, differences in elimination dependent upon route and schedule of administration, implications of the chirality of the drug and interpatient pharmacokinetic variability. The mechanisms of action of cytotoxicity, neurotoxicity, urotoxicity and nephrotoxicity have been pivotal issues in the assessment of the pharmacodynamics of ifosfamide. Correlations between the new insights into ifosfamide metabolism, pharmacokinetics and pharmacodynamics will rationalise the further development of therapeutic drug monitoring and dose individualisation of ifosfamide treatment.
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Affiliation(s)
- T Kerbusch
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute/ Slotervaart Hospital, Amsterdam.
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Gao K, Orgel LE. Nucleic acid duplexes incorporating a dissociable covalent base pair. Proc Natl Acad Sci U S A 1999; 96:14837-42. [PMID: 10611299 PMCID: PMC24734 DOI: 10.1073/pnas.96.26.14837] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have used molecular modeling techniques to design a dissociable covalently bonded base pair that can replace a Watson-Crick base pair in a nucleic acid with minimal distortion of the structure of the double helix. We introduced this base pair into a potential precursor of a nucleic acid double helix by chemical synthesis and have demonstrated efficient nonenzymatic template-directed ligation of the free hydroxyl groups of the base pair with appropriate short oligonucleotides. The nonenzymatic ligation reactions, which are characteristic of base paired nucleic acid structures, are abolished when the covalent base pair is reduced and becomes noncoplanar. This suggests that the covalent base pair linking the two strands in the duplex is compatible with a minimally distorted nucleic acid double-helical structure.
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Affiliation(s)
- K Gao
- The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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Sequence specificity for DNA interstrand cross-linking induced by anticancer drug chlorambucil. Arch Pharm Res 1997; 20:550-4. [DOI: 10.1007/bf02975210] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/1997] [Indexed: 10/21/2022]
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Lando DY, Fridman AS, Kabak AG, Akhrem AA. Melting of cross-linked DNA: II. Influence of interstrand linking on DNA stability. J Biomol Struct Dyn 1997; 15:141-50. [PMID: 9283987 DOI: 10.1080/07391102.1997.10508953] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the previous paper (D.Y. Lando, J. Biomol. Struct. Dynam, 15, 129-140 (1997)) the melting of cross-linked DNA with N base pairs and omega interstrand cross-links has been considered theoretically. In the present study on the basis of these results, two simple schemes are developed for the computation of melting curves of cross-linked DNA. The investigation of influence of interstrand linking on DNA stability has been carried out by computer simulation. It is shown that the relative concentration of cross-links, CCT = omega/N, their distribution along a DNA molecule, and particular values of the entropy factors of small loops formed by cross-links in melted regions strongly affect the DNA melting temperature, Tm. On the contrary, for DNA without cross-links, a ten-fold increase or decrease in the entropy factors of small loops does not cause the Tm variation. The comparison of the results of calculation with experimental data suggests that the majority of types of cross-link neither maintain ordered parallel orientation of bases in melted regions nor increase considerably the thermostability of cross-linked base pairs. Four different ways of influence of interstrand cross-linking on the DNA double helix stability are considered. It is shown that cross-linking significantly enhances the influence of single strand stiffness in melted regions on DNA melting behavior.
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Affiliation(s)
- D Y Lando
- Institute of Bioorganic Chemistry, Belarus Academy of Sciences, Minsk, Belarus.
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Bauer GB, Povirk LF. Specificity and kinetics of interstrand and intrastrand bifunctional alkylation by nitrogen mustards at a G-G-C sequence. Nucleic Acids Res 1997; 25:1211-8. [PMID: 9092631 PMCID: PMC146567 DOI: 10.1093/nar/25.6.1211] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Previous work showed that melphalan-induced mutations in the aprt gene of CHO cells are primarily transversions and occur preferentially at G-G-C sequences, which are potential sites for various bifunctional alkylations involving guanine N-7. To identify the DNA lesion(s) which may be responsible for these mutations, an end-labeled DNA duplex containing a frequent site of melphalan-induced mutation in the aprt gene was treated with melphalan, mechlorethamine or phosphoramide mustard. The sequence specificity and kinetics of formation of both interstrand and intrastrand crosslinks were determined. All mustards selectively formed two base-staggered interstrand crosslinks between the 5'G and the G opposite C in the 5'G-G-C sequence. Secondary alkylation was much slower for melphalan than for the other mustards and the resulting crosslink was more stable. Mechlorethamine and phosphoramide mustard induced intrastrand crosslinks between the two contiguous Gs in the G-G-C sequence in double-stranded DNA, but melphalan did not. Molecular dynamic simulations provided a structural explanation for this difference, in that the monofunctionally bound intermediates of mechlorethamine and phosphoramide mustard assumed thermodynamically stable conformations with the second arm in a position appropriate for intrastrand crosslink formation, while the corresponding melphalan monoadduct did not.
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Affiliation(s)
- G B Bauer
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA
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