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Zhou Q, Hao Y, Jie J, Wang S, Xia Y, Yang C, Liu L, Fang WH, Su H. Dual Functionality of 6-Methylthioguanine: Synergistic Effects Enhancing the Photolability of DNA Nucleobases. JACS AU 2024; 4:441-453. [PMID: 38425924 PMCID: PMC10900203 DOI: 10.1021/jacsau.3c00575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/05/2024] [Accepted: 01/05/2024] [Indexed: 03/02/2024]
Abstract
A small chemical modification of the nucleobase structure can significantly enhance the photoactivity of DNA, which may incur DNA damage, thus holding promising applications in photochemotherapy treatment of cancers or pathogens. However, single substitution confers only limited phototoxicity to DNA. Herein, we combine femtosecond and nanosecond time-resolved spectroscopy with high-level ab initio calculations to disentangle the excited-state dynamics of 6-methylthioguanine (me6-TG) under variable wavelength UVA excitation (310-330 nm). We find that double substitution of nucleobases (thionation and methylation) boosts the photoactivity by introducing more reactive channels. Intriguingly, 1nNπ*, rather than 1nSπ*, acts as the doorway state engendering the formation of the long-lived reactive triplet state in me6-TG. The 1nNπ* induces a low spin-orbit coupling of 8.3 cm-1, which increases the intersystem crossing (ISC) time (2.91 ± 0.14 ns). Despite the slowed ISC, the triplet quantum yield (ΦT) still accounts for a large fraction (0.6 ± 0.1), consistent with the potential energy surface that favors excited-state bifurcation to 1nNπ*min (3.36 ± 0.15 ps) rather than 1ππ*min (5.05 ± 0.26 ps), such that the subsequent ISC to triplet via 1nNπ*min constitutes the main relaxation pathway in me6-TG. Although this ΦT is inferior to its single-substituted predecessor 6-thioguanine (6-TG, 0.8 ± 0.2), the effect of thionation in synergy with methylation opens a unique C-S bond cleavage pathway through crossing to a repulsive 1πσ* state, generating thiyl radicals as highly reactive intermediates that may invoke biological damage. This photodissociation channel is extremely difficult for conventional nucleobases. These findings demonstrate the synergistic effects of double functionality substitution in modulating excited-state dynamics and enhancing the photolabile character of DNA nucleobases, providing inspirations for the rational design of advanced photodynamic and photochemotherapy approaches.
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Affiliation(s)
| | | | - Jialong Jie
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Shuo Wang
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ye Xia
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Chunfan Yang
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Lihong Liu
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Wei-Hai Fang
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Hongmei Su
- College of Chemistry, Beijing Normal University, Beijing 100875, China
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2
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Anand U, Dey A, Chandel AKS, Sanyal R, Mishra A, Pandey DK, De Falco V, Upadhyay A, Kandimalla R, Chaudhary A, Dhanjal JK, Dewanjee S, Vallamkondu J, Pérez de la Lastra JM. Cancer chemotherapy and beyond: Current status, drug candidates, associated risks and progress in targeted therapeutics. Genes Dis 2023; 10:1367-1401. [PMID: 37397557 PMCID: PMC10310991 DOI: 10.1016/j.gendis.2022.02.007] [Citation(s) in RCA: 221] [Impact Index Per Article: 221.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 02/15/2022] [Accepted: 02/21/2022] [Indexed: 11/28/2022] Open
Abstract
Cancer is an abnormal state of cells where they undergo uncontrolled proliferation and produce aggressive malignancies that causes millions of deaths every year. With the new understanding of the molecular mechanism(s) of disease progression, our knowledge about the disease is snowballing, leading to the evolution of many new therapeutic regimes and their successive trials. In the past few decades, various combinations of therapies have been proposed and are presently employed in the treatment of diverse cancers. Targeted drug therapy, immunotherapy, and personalized medicines are now largely being employed, which were not common a few years back. The field of cancer discoveries and therapeutics are evolving fast as cancer type-specific biomarkers are progressively being identified and several types of cancers are nowadays undergoing systematic therapies, extending patients' disease-free survival thereafter. Although growing evidence shows that a systematic and targeted approach could be the future of cancer medicine, chemotherapy remains a largely opted therapeutic option despite its known side effects on the patient's physical and psychological health. Chemotherapeutic agents/pharmaceuticals served a great purpose over the past few decades and have remained the frontline choice for advanced-stage malignancies where surgery and/or radiation therapy cannot be prescribed due to specific reasons. The present report succinctly reviews the existing and contemporary advancements in chemotherapy and assesses the status of the enrolled drugs/pharmaceuticals; it also comprehensively discusses the emerging role of specific/targeted therapeutic strategies that are presently being employed to achieve better clinical success/survival rate in cancer patients.
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Affiliation(s)
- Uttpal Anand
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Abhijit Dey
- Department of Life Sciences, Presidency University, Kolkata, West Bengal 700073, India
| | - Arvind K. Singh Chandel
- Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Rupa Sanyal
- Department of Botany, Bhairab Ganguly College (affiliated to West Bengal State University), Kolkata, West Bengal 700056, India
| | - Amarnath Mishra
- Faculty of Science and Technology, Amity Institute of Forensic Sciences, Amity University Uttar Pradesh, Noida 201313, India
| | - Devendra Kumar Pandey
- Department of Biotechnology, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara, Punjab 144411, India
| | - Valentina De Falco
- Institute of Endocrinology and Experimental Oncology (IEOS), National Research Council (CNR), Department of Molecular Medicine and Medical Biotechnology (DMMBM), University of Naples Federico II, Naples 80131, Italy
| | - Arun Upadhyay
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandar Sindari, Kishangarh Ajmer, Rajasthan 305817, India
| | - Ramesh Kandimalla
- CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana 500007, India
- Department of Biochemistry, Kakatiya Medical College, Warangal, Telangana 506007, India
| | - Anupama Chaudhary
- Orinin-BioSystems, LE-52, Lotus Road 4, CHD City, Karnal, Haryana 132001, India
| | - Jaspreet Kaur Dhanjal
- Department of Computational Biology, Indraprastha Institute of Information Technology Delhi (IIIT-D), Okhla Industrial Estate, Phase III, New Delhi 110020, India
| | - Saikat Dewanjee
- Advanced Pharmacognosy Research Laboratory, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India
| | - Jayalakshmi Vallamkondu
- Department of Physics, National Institute of Technology-Warangal, Warangal, Telangana 506004, India
| | - José M. Pérez de la Lastra
- Biotechnology of Macromolecules Research Group, Instituto de Productos Naturales y Agrobiología, IPNA-CSIC, San Cristóbal de La Laguna 38206, Tenerife, Spain
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3
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Guo S, Li L, Yu K, Tan Y, Wang Y. LC-MS/MS for Assessing the Incorporation and Repair of N2-Alkyl-2'-deoxyguanosine in Genomic DNA. Chem Res Toxicol 2022; 35:1814-1820. [PMID: 35584366 PMCID: PMC9588702 DOI: 10.1021/acs.chemrestox.2c00101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Understanding the occurrence, repair, and biological consequences of DNA damage is important in environmental toxicology and risk assessment. The most common way to assess DNA damage elicited by exogenous sources in a laboratory setting is to expose cells or experimental animals with chemicals that modify DNA. Owing to the lack of reaction specificities of DNA damaging agents, the approach frequently does not allow for induction of a specific DNA lesion. Herein, we employed metabolic labeling to selectively incorporate N2-methyl-dG (N2-MedG) and N2-n-butyl-dG (N2-nBudG) into genomic DNA of cultured mammalian cells, and investigated how the levels of the two lesions in cellular DNA are modulated by different DNA repair factors. Our results revealed that nucleotide excision repair (NER) exert moderate effects on the removal of N2-MedG and N2-nBudG from genomic DNA. We also observed that DNA polymerases κ and η contribute to the incorporation of N2-MedG into genomic DNA and modulate its repair in human cells. In addition, loss of ALKBH3 resulted in higher frequencies of N2-MedG and N2-nBuG incorporation into genomic DNA, suggesting a role of oxidative dealkylation in the reversal of these lesions. Together, our study provided new insights into the repair of minor-groove N2-alkyl-dG lesions in mammalian cells.
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Affiliation(s)
- Su Guo
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403, United States
| | - Lin Li
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Kailin Yu
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Ying Tan
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403, United States
| | - Yinsheng Wang
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521-0403, United States
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
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4
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Chan W, Jin L. DNA-Protein Cross-Links Formed by Reacting Lysine with Apurinic/Apyrimidinic Sites in DNA and Human Cells: Quantitative Analysis by Liquid Chromatography-Tandem Mass Spectrometry Coupled with Stable Isotope Dilution. Anal Chem 2021; 94:803-810. [PMID: 34971314 DOI: 10.1021/acs.analchem.1c03356] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Accumulating evidence suggests that DNA lesion-induced DNA-protein cross-links (DPCs) interrupt normal DNA metabolic processes, such as transcription, replication, and repair, resulting in profound biological consequences, including the development of many human diseases, such as cancers. Although apurinic/apyrimidinic (AP) sites are among the most predominant DNA lesions and are in close proximity to the histone proteins that they wrap around in the nucleosome, knowledge of the chemical structure or biological consequences of their associated DPCs is limited in part due to a lack of sensitive and selective analytical methods. We developed liquid chromatography-tandem mass spectrometry coupled with a stable isotope dilution method for rigorous quantitation of DPCs formed by reacting a DNA AP site with a lysine residue. In combination with chemical derivatization with fluorenylmethoxycarbonyl chloride to form a hydrophobic conjugate, the developed LC-MS/MS method allows sensitive detection of AP site-Lys cross-links down to sub-1 adduct per 106 nt. After validation using a synthetic AP site-lysine-cross-linked peptide and an oligodeoxyribonucleotide, the method was used to determine the concentration of AP site-lysine cross-links in hot acid-treated DNA and in human cells exposed to methyl methanesulfonate.
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Affiliation(s)
- Wan Chan
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Long Jin
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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5
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Chan W, Ham YH, Jin L, Chan HW, Wong YL, Chan CK, Chung PY. Quantification of a Novel DNA–Protein Cross-Link Product Formed by Reacting Apurinic/Apyrimidinic Sites in DNA with Cysteine Residues in Protein by Liquid Chromatography-Tandem Mass Spectrometry Coupled with the Stable Isotope-Dilution Method. Anal Chem 2019; 91:4987-4994. [DOI: 10.1021/acs.analchem.8b04306] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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6
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Ambati CR, Vantaku V, Donepudi SR, Amara CS, Ravi SS, Mandalapu A, Perla M, Putluri V, Sreekumar A, Putluri N. Measurement of methylated metabolites using Liquid Chromatography-Mass Spectrometry and its biological application. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2019; 11:49-57. [PMID: 31762797 PMCID: PMC6874373 DOI: 10.1039/c8ay02168f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Methylation aberrations play an important role in many metabolic disorders including cancer. Methylated metabolites are direct indicators of metabolic aberrations, and currently, there is no Liquid chromatography - Mass spectrometry (LC-MS) based method available to cover all classes of methylated metabolites at low detection limits. In this study, we have developed a method for the detection of methylated metabolites, and it's biological application. In this approach, we used a HILIC based HPLC with MS to measure methylated organic acids, amino acids, and nucleotides. These metabolites were separated from each other by their hydrophobic interactions and analyzed by targeted metabolomics of single reaction monitoring by positive and negative mode of electrospray ionization. These metabolites were quantified, and the interday reproducibility was <10% relative standard deviation. Furthermore, by applying this method, we identified high levels of methylated metabolites in bladder cancer cell lines compared to benign cells. In vitro treatment of cancer cells with methylation inhibitor, 5- aza-2'-deoxycytidine showed a decrease in these methylated metabolites. This data indicates that HPLC analysis using this HILIC based method could be a powerful tool for measuring methylated metabolites in biological specimens. This method is rapid, sensitive, selective, and precise to measure methylated metabolites.
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Affiliation(s)
- Chandrashekar R Ambati
- Advanced Technology Core, Dan L. Duncan Cancer Center, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, TX, USA
| | - Venkatrao Vantaku
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, TX, USA
| | - Sri Ramya Donepudi
- Advanced Technology Core, Dan L. Duncan Cancer Center, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, TX, USA
| | - Chandra Sekhar Amara
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, TX, USA
| | - Shiva Shankar Ravi
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, TX, USA
| | - Akhil Mandalapu
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, TX, USA
| | - Maharajni Perla
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, TX, USA
| | - Vasanta Putluri
- Advanced Technology Core, Dan L. Duncan Cancer Center, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, TX, USA
| | - Arun Sreekumar
- Advanced Technology Core, Dan L. Duncan Cancer Center, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, TX, USA
| | - Nagireddy Putluri
- Advanced Technology Core, Dan L. Duncan Cancer Center, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, TX, USA
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7
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Shipkova M, Valbuena H. Liquid chromatography tandem mass spectrometry for therapeutic drug monitoring of immunosuppressive drugs: Achievements, lessons and open issues. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2016.01.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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8
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Shipkova M, Svinarov D. LC–MS/MS as a tool for TDM services: Where are we? Clin Biochem 2016; 49:1009-23. [DOI: 10.1016/j.clinbiochem.2016.05.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 04/23/2016] [Accepted: 05/01/2016] [Indexed: 12/23/2022]
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9
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Karadas-Bakirhan N, Sarakbi A, Vandeput M, Ozkan SA, Kauffmann JM. Liquid Chromatography with Amperometric Detection at a Silver Based Detector for the Determination of Thiocompounds: Application to the Assay of Thiopurine Antimetabolites in Urine. Anal Chem 2015; 87:6730-5. [DOI: 10.1021/acs.analchem.5b00879] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Nurgul Karadas-Bakirhan
- Ankara University, Faculty of Pharmacy, Department
of Analytical Chemistry, 06100 Tandogan, Ankara, Turkey
| | - Ahmad Sarakbi
- Université libre de Bruxelles (ULB), Faculty of Pharmacy, Campus Plaine, CP 205/6, 1050 Bruxelles, Belgium
| | - Marie Vandeput
- Université libre de Bruxelles (ULB), Faculty of Pharmacy, Campus Plaine, CP 205/6, 1050 Bruxelles, Belgium
| | - Sibel A. Ozkan
- Ankara University, Faculty of Pharmacy, Department
of Analytical Chemistry, 06100 Tandogan, Ankara, Turkey
| | - Jean-Michel Kauffmann
- Université libre de Bruxelles (ULB), Faculty of Pharmacy, Campus Plaine, CP 205/6, 1050 Bruxelles, Belgium
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10
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Li L, Wang X, Li Q, Liu P, Xu K, Chen H, Tang B. An accurate mass spectrometric approach for the simultaneous comparison of GSH, Cys, and Hcy in L02 cells and HepG2 cells using new NPSP isotope probes. Chem Commun (Camb) 2015; 51:11317-20. [DOI: 10.1039/c5cc03157e] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
An accurate LC/ESI-MS method based on new NPSP isotope probes for simultaneous quantitative comparison of cellular biothiols.
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Affiliation(s)
- Lu Li
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Xiuli Wang
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Qingling Li
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Pengyuan Liu
- Center for Intelligent Chemical Instrumentation
- Department of Chemistry and Biochemistry
- Edison Biotechnology Institute
- Ohio University
- Athens
| | - Kehua Xu
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation
- Department of Chemistry and Biochemistry
- Edison Biotechnology Institute
- Ohio University
- Athens
| | - Bo Tang
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
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11
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Zhang F, Fu L, Wang Y. 6-thioguanine induces mitochondrial dysfunction and oxidative DNA damage in acute lymphoblastic leukemia cells. Mol Cell Proteomics 2013; 12:3803-11. [PMID: 24043426 DOI: 10.1074/mcp.m113.029595] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thiopurines are among the most successful chemotherapeutic agents used for treating various human diseases, including acute lymphoblastic leukemia and chronic inflammation. Although metabolic conversion and the subsequent incorporation of 6-thioguanine ((S)G) nucleotides into nucleic acids are considered important for allowing the thiopurine drugs to induce their cytotoxic effects, alternative mechanisms may also exist. We hypothesized that an unbiased analysis of (S)G-induced perturbation of the entire proteome might uncover novel mechanism(s) of action of the drug. We performed a quantitative assessment of global protein expression in control and (S)G-treated Jurkat T cells by employing stable isotope labeling by amino acids in cell culture and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. LC-MS/MS quantification results uncovered substantially decreased expression of a large number of proteins in the mitochondrial respiratory chain complex, and Ingenuity Pathway Analysis of the significantly altered proteins showed that (S)G treatment induced mitochondrial dysfunction. This was accompanied by diminished uptake of MitoTracker Deep Red and the elevated formation of oxidatively induced DNA lesions, including 8,5'-cyclo-2'-deoxyadenosine and 8,5'-cyclo-2'-deoxyguanosine. Together, our results suggested that (S)G may exert its cytotoxic effect by inducing mitochondrial dysfunction and reactive oxygen species formation in acute lymphoblastic leukemia cells.
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Affiliation(s)
- Fan Zhang
- Department of Chemistry, University of California, Riverside, California 92521-0403
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12
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Li J, Leung EMK, Choi MMF, Chan W. Combination of pentafluorophenylhydrazine derivatization and isotope dilution LC-MS/MS techniques for the quantification of apurinic/apyrimidinic sites in cellular DNA. Anal Bioanal Chem 2013; 405:4059-66. [PMID: 23423125 DOI: 10.1007/s00216-013-6823-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 01/31/2013] [Accepted: 02/04/2013] [Indexed: 01/09/2023]
Abstract
Apurinic/apyrimidinic (AP) sites are common DNA lesions arising from spontaneous hydrolysis of the N-glycosidic bond and base-excision repair mechanisms of the modified bases. Due to the strong association of AP site formation with physically/chemically induced DNA damage, quantifying AP sites provides important information for risk assessment of exposure to genotoxins and oxidative stress. However, rigorous quantification of AP sites in DNA has been hampered by technical problems relating to the sensitivity and selectivity of existing analytical methods. We have developed a new isotope dilution liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS) method for the rigorous quantification of AP sites in genomic DNA. The method entails enzymatic digestion of AP site-containing DNA by endo- and exonucleases, derivatization with pentafluorophenylhydrazine (PFPH), addition of an isotopically labeled PFPH derivative as internal standard, and quantification by LC-MS/MS. The combination of PFPH derivatization with LC-MS/MS analysis on a triple quadrupole mass spectrometer allows for sensitive and selective quantification of AP sites in DNA at a detection limit of 6.5 fmol, corresponding to 4 AP sites/10(9) nt in 5 μg of DNA, which is at least ten times more sensitive than existing analytical methods. The protocol was validated by AP site-containing oligonucleotides and applied in quantifying methyl methanesulfonate-induced formation of AP sites in cellular DNA.
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Affiliation(s)
- Jie Li
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, SAR, China
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13
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You C, Dai X, Yuan B, Wang Y. Effects of 6-thioguanine and S6-methylthioguanine on transcription in vitro and in human cells. J Biol Chem 2012; 287:40915-23. [PMID: 23076150 DOI: 10.1074/jbc.m112.418681] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Thiopurine drugs are extensively used as chemotherapeutic agents in clinical practice, even though there is concern about the risk of therapy-related cancers. It has been previously suggested that the cytotoxicity of thiopurine drugs involves their metabolic activation, the resultant generation of 6-thioguanine ((S)G) and S(6)-methylthioguanine (S(6)mG) in DNA, and the futile mismatch repair triggered by replication-induced (S)G:T and S(6)mG:T mispairs. Disruption of transcription is known to be one of the major consequences of DNA damage induced by many antiviral and antitumor agents; however, it remains undefined how (S)G and S(6)mG compromise the efficiency and fidelity of transcription. Using our recently developed competitive transcription and adduct bypass assay, herein we examined the impact of (S)G and S(6)mG on transcription in vitro and in human cells. Our results revealed that, when situated on the transcribed strand, S(6)mG exhibited both inhibitory and mutagenic effects during transcription mediated by single-subunit T7 RNA polymerase or multisubunit human RNA polymerase II in vitro and in human cells. Moreover, we found that the impact of S(6)mG on transcriptional efficiency and fidelity is modulated by the transcription-coupled nucleotide excision repair capacity. In contrast, (S)G did not considerably compromise the efficiency or fidelity of transcription, and it was a poor substrate for NER. We propose that S(6)mG might contribute, at least in part, to thiopurine-mediated cytotoxicity through inhibition of transcription and to potential therapy-related carcinogenesis via transcriptional mutagenesis.
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Affiliation(s)
- Changjun You
- Department of Chemistry, University of California, Riverside, California 92521-0403, USA
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14
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Hofmann U, Heinkele G, Angelberger S, Schaeffeler E, Lichtenberger C, Jaeger S, Reinisch W, Schwab M. Simultaneous quantification of eleven thiopurine nucleotides by liquid chromatography-tandem mass spectrometry. Anal Chem 2012; 84:1294-301. [PMID: 22220820 DOI: 10.1021/ac2031699] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The prodrugs azathioprine and 6-mercaptopurine, which are well-established anticancer and immunosuppressive agents, are extensively metabolized by activating and inactivating enzymes. Whereas the 6-thioguanine nucleotides (TGN) are currently being considered as major active metabolites, methylthioinosine nucleotides seem to contribute to the cytotoxic effect as well. Thiopurine-related adverse drug reactions and thiopurine failure are frequent. Thus, therapeutic monitoring of TGN and methylthioinosine derivatives has been suggested to improve thiopurine therapy, however with limited success. To elucidate systematically underlying molecular mechanisms as potential explanation for interindividual variability of thiopurine response, we developed a novel highly specific and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous quantitation of eleven mono-, di-, and triphosphates of thioguanosine, methylthioinosine, methylthioguanosine, and thioinosine. Using stable isotope-labeled analogues as internal standards obtained by chemical synthesis, an intra- and interassay variability below 8% and an accuracy of 92% to 107% were achieved in spiked quality control samples with known standards. All eleven metabolites could be determined in red blood cells from patients with inflammatory bowel diseases and long-term azathioprine therapy. Thus, our novel method opens a new avenue for the understanding of the thiopurine metabolism by quantitation of all important thiopurine nucleotide metabolites in one run.
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Affiliation(s)
- Ute Hofmann
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
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15
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Kretschy D, Gröger M, Zinkl D, Petzelbauer P, Koellensperger G, Hann S. High-throughput flow injection analysis of labeled peptides in cellular samples - ICP-MS analysis versus fluorescence based detection. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2011; 307:105-111. [PMID: 22723737 PMCID: PMC3378036 DOI: 10.1016/j.ijms.2011.02.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A high throughput method based on flow injection analysis was developed and validated for the quantification of the peptide Bβ(15-42) in cellular samples comparing different labeling strategies and detection methods. The used labels were 1,4,7,10-tetraazacyclododecane-N, N', N'', N'''-tetraaceticacid (In-DOTA) and 2-(4-isothiocyanatobenzyl) - 1,4,7,10-tetraazacyclododecane-N, N', N'', N'''-tetraacetic acid (In-DOTA-Bn) for elemental labeling. 6-Hydroxy-9-(2-carboxyphenyl)- (3H)-xanthen-3-on (fluorescein) was employed as fluorescence label. The explored peptide (mass = 3 kD) is a novel candidate drug, which shows an anti-inflammatory effect after an event of myocardial infarction. The analysed samples were fractioned cell compartments of human umbilical cord vein endothelial cells (HUVEC) maintained via lysis with Triton X buffer. In order to enhance sensitivity and selectivity of peptide quantification via flow injection the peptide was labeled prior to incubation using elemental and fluorescence labels. Quantification of the elemental and fluorescence labeled peptide was performed via flow injection analysis combined with inductive coupled plasma sector field mass spectrometry (FIA-ICP-SFMS) or fluorescence detection (FIA-FLD), respectively. The employed quantification strategies were external calibration in the case of fluorescence detection and external calibration with and without internal standardization and on-line IDMS in the case of ICP-MS detectionThe limit of detection (LOD) for FIA-ICP-MS was 9 pM In-DOTA-Bβ(15-42) (0.05 fmol absolute) whereas FIA-FLD showed a LOD of 100 pM (3 fmol absolute) for the fluorescein labeled peptide. Short term precision of FIA-ICP-MS was superior for all ICP-MS based quantification strategies compared to FIA-FLD (FIA-ICP-SFMS: 0.3-3.3%; FIA-FLD: 6.5%). Concerning long term precision FIA-ICP-SFMS with on-line IDMS and internal standardization showed the best results (3.1 and 4.6%, respectively) whereas the external calibration of both applied methodological approaches was only in the range of 10 %.The concentrations in the Triton X soluble fraction relative to the applied amount of Indium in the cell culture were in the range of 0.75-1.8% for In-DOTA or 0.30-0.79% for the 2-(4-isothiocyanatobenzyl) - 1,4,7,10-tetraazacyclododecane-N, N', N'', N'''-tetraacetic acid (In-DOTA-Bn) labeled peptide Bβ(15-42). In the Triton X insoluble fraction the relative concentrations of Indium were 0.03-0.18% for the In-DOTA labeled peptide and 0.03-0.13% for Bβ(15-42)-In-DOTA-Bn.
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Affiliation(s)
- Daniela Kretschy
- University of Natural Resources and Life Sciences, BOKU Vienna, Department of Chemistry, Division of Analytical Chemistry, Muthgasse 18, A-1190 Vienna, Austria
| | - Marion Gröger
- Department of Dermatology, Medical University of Vienna, Spitalgasse 23, A-1090 Vienna, Austria
| | - Daniela Zinkl
- Department of Dermatology, Medical University of Vienna, Spitalgasse 23, A-1090 Vienna, Austria
| | - Peter Petzelbauer
- Department of Dermatology, Medical University of Vienna, Spitalgasse 23, A-1090 Vienna, Austria
| | - Gunda Koellensperger
- University of Natural Resources and Life Sciences, BOKU Vienna, Department of Chemistry, Division of Analytical Chemistry, Muthgasse 18, A-1190 Vienna, Austria
| | - Stephan Hann
- University of Natural Resources and Life Sciences, BOKU Vienna, Department of Chemistry, Division of Analytical Chemistry, Muthgasse 18, A-1190 Vienna, Austria
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16
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Analysis of anticancer drugs: a review. Talanta 2011; 85:2265-89. [PMID: 21962644 DOI: 10.1016/j.talanta.2011.08.034] [Citation(s) in RCA: 325] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 08/15/2011] [Accepted: 08/16/2011] [Indexed: 01/05/2023]
Abstract
In the last decades, the number of patients receiving chemotherapy has considerably increased. Given the toxicity of cytotoxic agents to humans (not only for patients but also for healthcare professionals), the development of reliable analytical methods to analyse these compounds became necessary. From the discovery of new substances to patient administration, all pharmaceutical fields are concerned with the analysis of cytotoxic drugs. In this review, the use of methods to analyse cytotoxic agents in various matrices, such as pharmaceutical formulations and biological and environmental samples, is discussed. Thus, an overview of reported analytical methods for the determination of the most commonly used anticancer drugs is given.
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17
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Coulthard SA, Redfern CPF, Vikingsson S, Lindqvist-Appell M, Skoglund K, Jakobsen-Falk I, Hall AG, Taylor GA, Hogarth LA. Increased sensitivity to thiopurines in methylthioadenosine phosphorylase-deleted cancers. Mol Cancer Ther 2011; 10:495-504. [PMID: 21282358 DOI: 10.1158/1535-7163.mct-10-0798] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The thiopurines, 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG), are used in the treatment of leukemia. Incorporation of deoxythioguanosine nucleotides (dG(s)) into the DNA of thiopurine-treated cells causes cell death, but there is also evidence that thiopurine metabolites, particularly the 6-MP metabolite methylthioinosine monophosphate (MeTIMP), inhibit de novo purine synthesis (DNPS). The toxicity of DNPS inhibitors is influenced by methylthioadenosine phosphorylase (MTAP), a gene frequently deleted in cancers. Because the growth of MTAP-deleted tumor cells is dependent on DNPS or hypoxanthine salvage, we would predict such cells to show differential sensitivity to 6-MP and 6-TG. To test this hypothesis, sensitivity to 6-MP and 6-TG was compared in relation to MTAP status using cytotoxicity assays in two MTAP-deficient cell lines transfected to express MTAP: the T-cell acute lymphoblastic leukemic cell line, Jurkat, transfected with MTAP cDNA under the control of a tetracycline-inducible promoter, and a lung cancer cell line (A549-MTAP(-)) transfected to express MTAP constitutively (A549-MTAP(+)). Sensitivity to 6-MP or methyl mercaptopurine riboside, which is converted intracellularly to MeTIMP, was markedly higher in both cell lines under MTAP(-) conditions. Measurement of thiopurine metabolites support the hypothesis that DNPS inhibition is a major cause of cell death with 6-MP, whereas dG(s) incorporation is the main cause of cytotoxicity with 6-TG. These data suggest that thiopurines, particularly 6-MP, may be more effective in patients with deleted MTAP.
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Affiliation(s)
- Sally A Coulthard
- Newcastle Cancer Centre at the Northern Institute for Cancer Research, Newcastle University, Paul O'Gorman Building, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, United Kingdom.
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18
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Yuan B, Zhang J, Wang H, Xiong L, Cai Q, Wang T, Jacobsen S, Pradhan S, Wang Y. 6-Thioguanine reactivates epigenetically silenced genes in acute lymphoblastic leukemia cells by facilitating proteasome-mediated degradation of DNMT1. Cancer Res 2011; 71:1904-11. [PMID: 21239472 DOI: 10.1158/0008-5472.can-10-3430] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Thiopurines including 6-thioguanine ((S)G), 6-mercaptopurine, and azathioprine are effective anticancer agents with remarkable success in clinical practice, especially in effective treatment of acute lymphoblastic leukemia (ALL). (S)G is understood to act as a DNA hypomethylating agent in ALL cells, however, the underlying mechanism leading to global cytosine demethylation remains unclear. Here we report that (S)G treatment results in reactivation of epigenetically silenced genes in T leukemia cells. Bisulfite genomic sequencing revealed that (S)G treatment universally elicited demethylation in the promoters and/or first exons of the genes that were reactivated. (S)G treatment also attenuated the expression of histone lysine-specific demethylase 1 (LSD1), thereby stimulating lysine methylation of the DNA methylase DNMT1 and triggering its degradation via the ubiquitin-proteasomal pathway. Taken together, our findings reveal a previously uncharacterized but vital mechanistic link between (S)G treatment and DNA hypomethylation.
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Affiliation(s)
- Bifeng Yuan
- Department of Chemistry, University of California, Riverside, California 92521-0403, USA
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19
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Yuan B, O’Connor TR, Wang Y. 6-Thioguanine and S⁶-methylthioguanine are mutagenic in human cells. ACS Chem Biol 2010; 5:1021-7. [PMID: 20806951 DOI: 10.1021/cb100214b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thiopurines are effective immunosuppressants and anticancer agents. However, the long-term use of thiopurines was found to be associated with a significantly increased risk of various types of cancer. To date, the specific mechanism(s) underlying the carcinogenicity associated with thiopurine treatment remain(s) unclear. Herein, we constructed duplex pTGFP-Hha10 shuttle vectors carrying a 6-thioguanine ((S)G) or S⁶-methylthioguanine (S⁶mG) at a unique site and allowed the vectors to propagate in three different human cell lines. Analysis of the replication products revealed that although neither thionucleoside blocked considerably DNA replication in any of the human cell lines, both (S)G and S⁶mG were mutagenic, resulting in G→A mutation at frequencies of ~8% and ~39%, respectively. Consistent with what was found from our previous study in E. coli cells, our data demonstrated that the mutagenic properties of (S)G and S⁶mG provided significant evidence for mutation induction as a potential carcinogenic mechanism associated with chronic thiopurine intervention.
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Affiliation(s)
- Bifeng Yuan
- Department of Chemistry, University of California, Riverside, California 92521
| | - Timothy R. O’Connor
- Biology Division, Beckman Research Institute, City of Hope National Medical Center, Duarte, California 91010
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, California 92521
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