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Fang Q. The Versatile Attributes of MGMT: Its Repair Mechanism, Crosstalk with Other DNA Repair Pathways, and Its Role in Cancer. Cancers (Basel) 2024; 16:331. [PMID: 38254819 PMCID: PMC10814553 DOI: 10.3390/cancers16020331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
O6-methylguanine-DNA methyltransferase (MGMT or AGT) is a DNA repair protein with the capability to remove alkyl groups from O6-AlkylG adducts. Moreover, MGMT plays a crucial role in repairing DNA damage induced by methylating agents like temozolomide and chloroethylating agents such as carmustine, and thereby contributes to chemotherapeutic resistance when these agents are used. This review delves into the structural roles and repair mechanisms of MGMT, with emphasis on the potential structural and functional roles of the N-terminal domain of MGMT. It also explores the development of cancer therapeutic strategies that target MGMT. Finally, it discusses the intriguing crosstalk between MGMT and other DNA repair pathways.
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Affiliation(s)
- Qingming Fang
- Department of Biochemistry and Structural Biology, Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX 78229, USA
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2
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Sun G, Bai P, Fan T, Zhao L, Zhong R, McElhinney RS, McMurry TBH, Donnelly DJ, McCormick JE, Kelly J, Margison GP. QSAR and Chemical Read-Across Analysis of 370 Potential MGMT Inactivators to Identify the Structural Features Influencing Inactivation Potency. Pharmaceutics 2023; 15:2170. [PMID: 37631385 PMCID: PMC10458236 DOI: 10.3390/pharmaceutics15082170] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/16/2023] [Accepted: 08/19/2023] [Indexed: 08/27/2023] Open
Abstract
O6-methylguanine-DNA methyltransferase (MGMT) constitutes an important cellular mechanism for repairing potentially cytotoxic DNA damage induced by guanine O6-alkylating agents and can render cells highly resistant to certain cancer chemotherapeutic drugs. A wide variety of potential MGMT inactivators have been designed and synthesized for the purpose of overcoming MGMT-mediated tumor resistance. We determined the inactivation potency of these compounds against human recombinant MGMT using [3H]-methylated-DNA-based MGMT inactivation assays and calculated the IC50 values. Using the results of 370 compounds, we performed quantitative structure-activity relationship (QSAR) modeling to identify the correlation between the chemical structure and MGMT-inactivating ability. Modeling was based on subdividing the sorted pIC50 values or on chemical structures or was random. A total of nine molecular descriptors were presented in the model equation, in which the mechanistic interpretation indicated that the status of nitrogen atoms, aliphatic primary amino groups, the presence of O-S at topological distance 3, the presence of Al-O-Ar/Ar-O-Ar/R..O..R/R-O-C=X, the ionization potential and hydrogen bond donors are the main factors responsible for inactivation ability. The final model was of high internal robustness, goodness of fit and prediction ability (R2pr = 0.7474, Q2Fn = 0.7375-0.7437, CCCpr = 0.8530). After the best splitting model was decided, we established the full model based on the entire set of compounds using the same descriptor combination. We also used a similarity-based read-across technique to further improve the external predictive ability of the model (R2pr = 0.7528, Q2Fn = 0.7387-0.7449, CCCpr = 0.8560). The prediction quality of 66 true external compounds was checked using the "Prediction Reliability Indicator" tool. In summary, we defined key structural features associated with MGMT inactivation, thus allowing for the design of MGMT inactivators that might improve clinical outcomes in cancer treatment.
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Affiliation(s)
- Guohui Sun
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China; (P.B.); (T.F.); (L.Z.); (R.Z.)
| | - Peiying Bai
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China; (P.B.); (T.F.); (L.Z.); (R.Z.)
| | - Tengjiao Fan
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China; (P.B.); (T.F.); (L.Z.); (R.Z.)
- Department of Medical Technology, Beijing Pharmaceutical University of Staff and Workers, Beijing 100079, China
| | - Lijiao Zhao
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China; (P.B.); (T.F.); (L.Z.); (R.Z.)
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China; (P.B.); (T.F.); (L.Z.); (R.Z.)
| | - R. Stanley McElhinney
- Chemistry Department, Trinity College, D02 PN40 Dublin, Ireland; (T.B.H.M.); (D.J.D.)
| | - T. Brian H. McMurry
- Chemistry Department, Trinity College, D02 PN40 Dublin, Ireland; (T.B.H.M.); (D.J.D.)
| | - Dorothy J. Donnelly
- Chemistry Department, Trinity College, D02 PN40 Dublin, Ireland; (T.B.H.M.); (D.J.D.)
| | - Joan E. McCormick
- Chemistry Department, Trinity College, D02 PN40 Dublin, Ireland; (T.B.H.M.); (D.J.D.)
| | - Jane Kelly
- Carcinogenesis Department, Paterson Institute for Cancer Research, Manchester M20 9BX, UK;
| | - Geoffrey P. Margison
- Carcinogenesis Department, Paterson Institute for Cancer Research, Manchester M20 9BX, UK;
- Epidemiology and Public Health Group, School of Health Sciences, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PG, UK
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3
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Bai P, Fan T, Sun G, Wang X, Zhao L, Zhong R. The dual role of DNA repair protein MGMT in cancer prevention and treatment. DNA Repair (Amst) 2023; 123:103449. [PMID: 36680944 DOI: 10.1016/j.dnarep.2023.103449] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 12/21/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
Alkylating agents are genotoxic chemicals that can induce and treat various types of cancer. This occurs through covalent bonding with cellular macromolecules, in particular DNA, leading to the loss of functional integrity under the persistence of modifications upon replication. O6-alkylguanine (O6-AlkylG) adducts are proposed to be the most potent DNA lesions induced by alkylating agents. If not repaired correctly, these adducts can result, at the molecular level, in DNA point mutations, chromosome aberrations, recombination, crosslinking, and single- and double-strand breaks (SSB/DSBs). At the cellular level, these lesions can result in malignant transformation, senescence, or cell death. O6-methylguanine-DNA methyltransferase (MGMT) is a DNA repair protein capable of removing the alkyl groups from O6-AlkylG adducts in a damage reversal process that can prevent the adverse biological effects of DNA damage caused by guanine O6-alkylation. MGMT can thereby defend normal cells against tumor initiation, however it can also protect tumor cells against the beneficial effects of chemotherapy. Hence, MGMT can play an important role in both the prevention and treatment of cancer; thus, it can be considered as a double-edged sword. From a clinical perspective, MGMT is a therapeutic target, and it is important to explore the rational development of its clinical exploitation.
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Affiliation(s)
- Peiying Bai
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Tengjiao Fan
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China; Department of Medical Technology, Beijing Pharmaceutical University of Staff and Workers, Beijing 100079, China
| | - Guohui Sun
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China.
| | - Xin Wang
- Department of Clinical Trials Center, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100029, China
| | - Lijiao Zhao
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
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Du H, Jiang D, Gao J, Zhang X, Jiang L, Zeng Y, Wu Z, Shen C, Xu L, Cao D, Hou T, Pan P. Proteome-Wide Profiling of the Covalent-Druggable Cysteines with a Structure-Based Deep Graph Learning Network. Research (Wash D C) 2022; 2022:9873564. [PMID: 35958111 PMCID: PMC9343084 DOI: 10.34133/2022/9873564] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/27/2022] [Indexed: 11/06/2022] Open
Abstract
Covalent ligands have attracted increasing attention due to their unique advantages, such as long residence time, high selectivity, and strong binding affinity. They also show promise for targets where previous efforts to identify noncovalent small molecule inhibitors have failed. However, our limited knowledge of covalent binding sites has hindered the discovery of novel ligands. Therefore, developing in silico methods to identify covalent binding sites is highly desirable. Here, we propose DeepCoSI, the first structure-based deep graph learning model to identify ligandable covalent sites in the protein. By integrating the characterization of the binding pocket and the interactions between each cysteine and the surrounding environment, DeepCoSI achieves state-of-the-art predictive performances. The validation on two external test sets which mimic the real application scenarios shows that DeepCoSI has strong ability to distinguish ligandable sites from the others. Finally, we profiled the entire set of protein structures in the RCSB Protein Data Bank (PDB) with DeepCoSI to evaluate the ligandability of each cysteine for covalent ligand design, and made the predicted data publicly available on website.
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Affiliation(s)
- Hongyan Du
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
- State Key Lab of CAD&CG, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Dejun Jiang
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
- State Key Lab of CAD&CG, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Junbo Gao
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Xujun Zhang
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Lingxiao Jiang
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Yundian Zeng
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Zhenxing Wu
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Chao Shen
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Lei Xu
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Dongsheng Cao
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410004 Hunan, China
| | - Tingjun Hou
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
- State Key Lab of CAD&CG, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Peichen Pan
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
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Zhang Y, Han L, Tian X, Peng C, Chen Y. Ligand‐Directed Caging Enables the Control of Endogenous DNA Alkyltransferase Activity with Light inside Live Cells. Angew Chem Int Ed Engl 2022; 61:e202115472. [DOI: 10.1002/anie.202115472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Indexed: 12/29/2022]
Affiliation(s)
- Yixin Zhang
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
| | - Lili Han
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- School of Physical Science and Technology ShanghaiTech University 100 Haike Road Shanghai 201210 China
| | - Xiaoxu Tian
- National Facility for Protein Science in Shanghai Zhangjiang Lab Shanghai Advanced Research Institute Chinese Academy of Science Shanghai 201210 China
| | - Chao Peng
- National Facility for Protein Science in Shanghai Zhangjiang Lab Shanghai Advanced Research Institute Chinese Academy of Science Shanghai 201210 China
| | - Yiyun Chen
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- School of Physical Science and Technology ShanghaiTech University 100 Haike Road Shanghai 201210 China
- School of Chemistry and Material Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences 1 Sub-lane Xiangshan Hangzhou 310024 China
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6
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Zhang Y, Han L, Tian X, Peng C, Chen Y. Ligand‐Directed Caging Enables the Control of Endogenous DNA Alkyltransferase Activity with Light inside Live Cells. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202115472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yixin Zhang
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
| | - Lili Han
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- School of Physical Science and Technology ShanghaiTech University 100 Haike Road Shanghai 201210 China
| | - Xiaoxu Tian
- National Facility for Protein Science in Shanghai Zhangjiang Lab Shanghai Advanced Research Institute Chinese Academy of Science Shanghai 201210 China
| | - Chao Peng
- National Facility for Protein Science in Shanghai Zhangjiang Lab Shanghai Advanced Research Institute Chinese Academy of Science Shanghai 201210 China
| | - Yiyun Chen
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- School of Physical Science and Technology ShanghaiTech University 100 Haike Road Shanghai 201210 China
- School of Chemistry and Material Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences 1 Sub-lane Xiangshan Hangzhou 310024 China
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7
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Franco Pinto J, Fillion A, Duchambon P, Bombard S, Granzhan A. Acridine-O 6-benzylguanine hybrids: Synthesis, DNA binding, MGMT inhibition and antiproliferative activity. Eur J Med Chem 2021; 227:113909. [PMID: 34731767 DOI: 10.1016/j.ejmech.2021.113909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/24/2021] [Accepted: 10/06/2021] [Indexed: 12/13/2022]
Abstract
O6-Methylguanine-DNA-methyltransferase (MGMT) is a key DNA repair enzyme involved in chemoresistance to DNA-alkylating anti-cancer drugs such as Temozolomide (TMZ) through direct repair of drug-induced O6-methylguanine residues in DNA. MGMT substrate analogues, such as O6-benzylguanine (BG), efficiently inactivate MGMT in vitro and in cells; however, these drugs failed to reach the clinic due to adverse side effects. Here, we designed hybrid drugs combining a BG residue covalently linked to a DNA-interacting moiety (6-chloro-2-methoxy-9-aminoacridine). Specifically, two series of hybrids, encompassing three compounds each, were obtained by varying the position of the attachment point of BG (N9 of guanine vs. the benzyl group) and the length and nature of the linker. UV/vis absorption and fluorescence data indicate that all six hybrids adopt an intramolecularly stacked conformation in aqueous solutions in a wide range of temperatures. All hybrids interact with double-stranded DNA, as clearly evidenced by spectrophotometric titrations, without intercalation of the acridine ring and do not induce thermal stabilization of the duplex. All hybrids, as well as the reference DNA intercalator (6-chloro-2-methoxy-9-aminoacridine 8), irreversibly inhibit MGMT in vitro with variable efficiency, comparable to that of BG. In a multidrug-resistant glioblastoma cell line T98G, benzyl-linked hybrids 7a-c and the N9-linked hybrid 19b are moderately cytotoxic (GI50 ≥ 15 μM after 96 h), while N9-linked hybrids 19a and 19c are strongly cytotoxic (GI50 = 1-2 μM), similarly to acridine 8 (GI50 = 0.6 μM). Among all compounds, hybrids 19a and 19c, similarly to BG, display synergic cytotoxic effect upon co-treatment with subtoxic doses of TMZ, with combination index (CI) values as low as 0.2-0.3. In agreement with in vitro results, compound 19a inactivates cellular MGMT but, unlike BG, does not induce significant levels of DNA damage, either alone or in combination with TMZ, as indicated by the results of γH2AX immunostaining experiments. Instead, and unlike BG, compound 19a alone induces significant apoptosis of T98G cells, which is not further increased in a combination with TMZ. These results indicate that molecular mechanisms underlying the cytotoxicity of 19a and its combination with TMZ are distinct from that of BG. The strongly synergic properties of this combination represent an interesting therapeutic opportunity in treating TMZ-resistant cancers.
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Affiliation(s)
- Jaime Franco Pinto
- CNRS UMR9187, Inserm U1196, Institut Curie, PSL Research University, 91405, Orsay, France; CNRS UMR9187, Inserm U1196, Université Paris Saclay, 91405, Orsay, France
| | - Alexandra Fillion
- CNRS UMR9187, Inserm U1196, Institut Curie, PSL Research University, 91405, Orsay, France; CNRS UMR9187, Inserm U1196, Université Paris Saclay, 91405, Orsay, France
| | - Patricia Duchambon
- CNRS UMR9187, Inserm U1196, Institut Curie, PSL Research University, 91405, Orsay, France; CNRS UMR9187, Inserm U1196, Université Paris Saclay, 91405, Orsay, France
| | - Sophie Bombard
- CNRS UMR9187, Inserm U1196, Institut Curie, PSL Research University, 91405, Orsay, France; CNRS UMR9187, Inserm U1196, Université Paris Saclay, 91405, Orsay, France.
| | - Anton Granzhan
- CNRS UMR9187, Inserm U1196, Institut Curie, PSL Research University, 91405, Orsay, France; CNRS UMR9187, Inserm U1196, Université Paris Saclay, 91405, Orsay, France.
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Reductive Activity and Mechanism of Hypoxia- Targeted AGT Inhibitors: An Experimental and Theoretical Investigation. Int J Mol Sci 2019; 20:ijms20246308. [PMID: 31847200 PMCID: PMC6941096 DOI: 10.3390/ijms20246308] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/05/2019] [Accepted: 12/10/2019] [Indexed: 11/16/2022] Open
Abstract
O6-alkylguanine-DNA alkyltransferase (AGT) is the main cause of tumor cell resistance to DNA-alkylating agents, so it is valuable to design tumor-targeted AGT inhibitors with hypoxia activation. Based on the existing benchmark inhibitor O6-benzylguanine (O6-BG), four derivatives with hypoxia-reduced potential and their corresponding reduction products were synthesized. A reductase system consisting of glucose/glucose oxidase, xanthine/xanthine oxidase, and catalase were constructed, and the reduction products of the hypoxia-activated prodrugs under normoxic and hypoxic conditions were determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The results showed that the reduction products produced under hypoxic conditions were significantly higher than that under normoxic condition. The amount of the reduction product yielded from ANBP (2-nitro-6-(3-amino) benzyloxypurine) under hypoxic conditions was the highest, followed by AMNBP (2-nitro-6-(3-aminomethyl)benzyloxypurine), 2-NBP (2-nitro-6-benzyloxypurine), and 3-NBG (O6-(3-nitro)benzylguanine). It should be noted that although the levels of the reduction products of 2-NBP and 3-NBG were lower than those of ANBP and AMNBP, their maximal hypoxic/normoxic ratios were higher than those of the other two prodrugs. Meanwhile, we also investigated the single electron reduction mechanism of the hypoxia-activated prodrugs using density functional theory (DFT) calculations. As a result, the reduction of the nitro group to the nitroso was proven to be a rate-limiting step. Moreover, the 2-nitro group of purine ring was more ready to be reduced than the 3-nitro group of benzyl. The energy barriers of the rate-limiting steps were 34–37 kcal/mol. The interactions between these prodrugs and nitroreductase were explored via molecular docking study, and ANBP was observed to have the highest affinity to nitroreductase, followed by AMNBP, 2-NBP, and 3-NBG. Interestingly, the theoretical results were generally in a good agreement with the experimental results. Finally, molecular docking and molecular dynamics simulations were performed to predict the AGT-inhibitory activity of the four prodrugs and their reduction products. In summary, simultaneous consideration of reduction potential and hypoxic selectivity is necessary to ensure that such prodrugs have good hypoxic tumor targeting. This study provides insights into the hypoxia-activated mechanism of nitro-substituted prodrugs as AGT inhibitors, which may contribute to reasonable design and development of novel tumor-targeted AGT inhibitors.
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NBGNU: a hypoxia-activated tripartite combi-nitrosourea prodrug overcoming AGT-mediated chemoresistance. Future Med Chem 2018; 11:269-284. [PMID: 30560688 DOI: 10.4155/fmc-2018-0511] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Aim: A hypoxia-activated combi-nitrosourea prodrug, N-(2-chloroethyl)-N'-2-(2-(4-nitrobenzylcarbamate)-O 6-benzyl-9-guanine)ethyl-N-nitrosourea (NBGNU), was synthesized and evaluated for its hypoxic selectivity and anticancer activity in vitro. Results: The prodrug was designed as a tripartite molecule consisting of a chloroethylnitrosourea pharmacophore to induce DNA interstrand crosslinks (ICLs) and an O 6-benzylguanine analog moiety masked by a 4-nitrobenzylcarbamate group to induce hypoxia-activated inhibition of O 6-alkylguanine-DNA alkyltransferase. NBGNU was tested for hypoxic selectivity, cytotoxicity and DNA ICLs ability. The reduction product amounts, cell death rates and DNA ICL levels induced by NBGNU under hypoxic conditions were all significantly higher than those induced by NBGNU under normoxic conditions. Conclusion: The tripartite combi-nitrosourea prodrug exhibits desirable tumor-hypoxia targeting ability and abolished chemoresistance compared with the conventional chloroethylnitrosoureas.
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Sun G, Fan T, Sun X, Hao Y, Cui X, Zhao L, Ren T, Zhou Y, Zhong R, Peng Y. In Silico Prediction of O⁶-Methylguanine-DNA Methyltransferase Inhibitory Potency of Base Analogs with QSAR and Machine Learning Methods. Molecules 2018; 23:E2892. [PMID: 30404161 PMCID: PMC6278368 DOI: 10.3390/molecules23112892] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 11/04/2018] [Accepted: 11/06/2018] [Indexed: 12/24/2022] Open
Abstract
O⁶-methylguanine-DNA methyltransferase (MGMT), a unique DNA repair enzyme, can confer resistance to DNA anticancer alkylating agents that modify the O⁶-position of guanine. Thus, inhibition of MGMT activity in tumors has a great interest for cancer researchers because it can significantly improve the anticancer efficacy of such alkylating agents. In this study, we performed a quantitative structure activity relationship (QSAR) and classification study based on a total of 134 base analogs related to their ED50 values (50% inhibitory concentration) against MGMT. Molecular information of all compounds were described by quantum chemical descriptors and Dragon descriptors. Genetic algorithm (GA) and multiple linear regression (MLR) analysis were combined to develop QSAR models. Classification models were generated by seven machine-learning methods based on six types of molecular fingerprints. Performances of all developed models were assessed by internal and external validation techniques. The best QSAR model was obtained with Q²Loo = 0.83, R² = 0.87, Q²ext = 0.67, and R²ext = 0.69 based on 84 compounds. The results from QSAR studies indicated topological charge indices, polarizability, ionization potential (IP), and number of primary aromatic amines are main contributors for MGMT inhibition of base analogs. For classification studies, the accuracies of 10-fold cross-validation ranged from 0.750 to 0.885 for top ten models. The range of accuracy for the external test set ranged from 0.800 to 0.880 except for PubChem-Tree model, suggesting a satisfactory predictive ability. Three models (Ext-SVM, Ext-Tree and Graph-RF) showed high and reliable predictive accuracy for both training and external test sets. In addition, several representative substructures for characterizing MGMT inhibitors were identified by information gain and substructure frequency analysis method. Our studies might be useful for further study to design and rapidly identify potential MGMT inhibitors.
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Affiliation(s)
- Guohui Sun
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Tengjiao Fan
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Xiaodong Sun
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Yuxing Hao
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Xin Cui
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Lijiao Zhao
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Ting Ren
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Yue Zhou
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, 2A Nanwei Road, Beijing 100050, China.
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment & Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China.
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11
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The specific role of O 6-methylguanine-DNA methyltransferase inhibitors in cancer chemotherapy. Future Med Chem 2018; 10:1971-1996. [PMID: 30001630 DOI: 10.4155/fmc-2018-0069] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The DNA repair protein, O6-methylguanine DNA methyltransferase (MGMT), can confer resistance to guanine O6-alkylating agents. Therefore, inhibition of resistant MGMT protein is a practical approach to increase the anticancer effects of such alkylating agents. Numerous small molecule inhibitors were synthesized and exhibited potential MGMT inhibitory activities. Although they were nontoxic alone, they also inhibited MGMT in normal tissues, thereby enhancing the side effects of chemotherapy. Therefore, strategies for tumor-specific MGMT inhibition have been proposed, including local drug delivery and tumor-activated prodrugs. Over-expression of MGMT in hematopoietic stem cells to protect bone marrow from the toxic effects of chemotherapy is also a feasible selection. The future prospects and challenges of MGMT inhibitors in cancer chemotherapy were also discussed.
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Affiliation(s)
- Justin A. Modica
- Departments of Chemistry and Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60201, United States
| | - Yao Lin
- Departments of Chemistry and Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60201, United States
| | - Milan Mrksich
- Departments of Chemistry and Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60201, United States
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Koyama H, Ikenuma H, Toda H, Kondo G, Hirano M, Kato M, Abe J, Yamada T, Wakabayashi T, Ito K, Natsume A, Suzuki M. Synthesis of PET probe O 6-[(3-[ 11C]methyl)benzyl]guanine by Pd 0-mediated rapid C-[ 11C]methylation toward imaging DNA repair protein O 6-methylguanine-DNA methyltransferase in glioblastoma. Bioorg Med Chem Lett 2017; 27:1892-1896. [PMID: 28363750 DOI: 10.1016/j.bmcl.2017.03.045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 02/28/2017] [Accepted: 03/17/2017] [Indexed: 12/31/2022]
Abstract
O6-Benzylguanine (O6-BG) is a substrate of O6-methylguanine-DNA methyltransferase (MGMT), which is involved in drug resistance of chemotherapy in the majority of glioblastoma multiform. For clinical diagnosis, it is hoped that the MGMT expression level could be determined by a noninvasive method to understand the detailed biological properties of MGMT-specific tumors. We synthesized 11C-labeled O6-[(3-methyl)benzyl]guanine ([11C]mMeBG) as a positron emission tomography probe. Thus, a mixed amine-protected stannyl precursor, N9-(tert-butoxycarbonyl)-O6-[3-(tributylstannyl)benzyl]-N2-(trifluoroacetyl)guanine, was subjected to rapid C-[11C]methylation under [11C]CH3I/[Pd2(dba)3]/P(o-CH3C6H4)3/CuCl/K2CO3 in NMP, followed by quick deprotection with LiOH/H2O, giving [11C]mMeBG with total radioactivity of 1.34GBq and ≥99% radiochemical and chemical purities.
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Affiliation(s)
- Hiroko Koyama
- Division of Regeneration and Advanced Medical Science, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194, Japan.
| | - Hiroshi Ikenuma
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, 7-430 Morioka-cho, Obu-shi, Aichi 474-8511, Japan
| | - Hiroshi Toda
- Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Goro Kondo
- Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Masaki Hirano
- Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Masaya Kato
- Division of Regeneration and Advanced Medical Science, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194, Japan
| | - Junichiro Abe
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, 7-430 Morioka-cho, Obu-shi, Aichi 474-8511, Japan
| | - Takashi Yamada
- Department of Food and Nutritional Science, College of Bioscience and Biotechnology, Chubu University, Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
| | - Toshihiko Wakabayashi
- Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Kengo Ito
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, 7-430 Morioka-cho, Obu-shi, Aichi 474-8511, Japan
| | - Atsushi Natsume
- Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Masaaki Suzuki
- Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, 7-430 Morioka-cho, Obu-shi, Aichi 474-8511, Japan.
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14
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Elucidating a chemical defense mechanism of Antarctic sponges: A computational study. J Mol Graph Model 2016; 71:104-115. [PMID: 27894019 DOI: 10.1016/j.jmgm.2016.11.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/21/2016] [Accepted: 11/06/2016] [Indexed: 11/22/2022]
Abstract
In 2000, a novel secondary metabolite (erebusinone, Ereb) was isolated from the Antarctic sea sponge, Isodictya erinacea. The bioactivity of Ereb was investigated, and it was found to inhibit molting when fed to the arthropod species Orchomene plebs. Xanthurenic acid (XA) is a known endogenous molt regulator present in arthropods. Experimental studies have confirmed that XA inhibits molting by binding to either (or both) of two P450 enzymes (CYP315a1 or CYP314a1) that are responsible for the final two hydroxylations in the production of the molt-inducing hormone, 20-hydroxyecdysone (20E). The lack of crystal structures and biochemical assays for CYP315a1 or CYP314a1, has prevented further experimental exploration of XA and Ereb's molt inhibition mechanisms. Herein, a wide array of computational techniques - homology modeling, molecular dynamics simulations, binding site bioinformatics, flexible receptor-flexible ligand docking, and molecular mechanics-generalized Born surface area calculations - have been employed to elucidate the structure-function relationships between the aforementioned P450s and the two described small molecule inhibitors (Ereb and XA). Results indicate that Ereb likely targets CYP315a1 by interacting with a network of aromatic residues in the binding site, while XA may inhibit both CYP315a1 and CYP314a1 because of its aromatic, as well as charged nature.
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Identification of the Structural Features of Guanine Derivatives as MGMT Inhibitors Using 3D-QSAR Modeling Combined with Molecular Docking. Molecules 2016; 21:molecules21070823. [PMID: 27347909 PMCID: PMC6273773 DOI: 10.3390/molecules21070823] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/08/2016] [Accepted: 06/18/2016] [Indexed: 01/29/2023] Open
Abstract
DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT), which plays an important role in inducing drug resistance against alkylating agents that modify the O6 position of guanine in DNA, is an attractive target for anti-tumor chemotherapy. A series of MGMT inhibitors have been synthesized over the past decades to improve the chemotherapeutic effects of O6-alkylating agents. In the present study, we performed a three-dimensional quantitative structure activity relationship (3D-QSAR) study on 97 guanine derivatives as MGMT inhibitors using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methods. Three different alignment methods (ligand-based, DFT optimization-based and docking-based alignment) were employed to develop reliable 3D-QSAR models. Statistical parameters derived from the models using the above three alignment methods showed that the ligand-based CoMFA (Qcv2 = 0.672 and Rncv2 = 0.997) and CoMSIA (Qcv2 = 0.703 and Rncv2 = 0.946) models were better than the other two alignment methods-based CoMFA and CoMSIA models. The two ligand-based models were further confirmed by an external test-set validation and a Y-randomization examination. The ligand-based CoMFA model (Qext2 = 0.691, Rpred2 = 0.738 and slope k = 0.91) was observed with acceptable external test-set validation values rather than the CoMSIA model (Qext2 = 0.307, Rpred2 = 0.4 and slope k = 0.719). Docking studies were carried out to predict the binding modes of the inhibitors with MGMT. The results indicated that the obtained binding interactions were consistent with the 3D contour maps. Overall, the combined results of the 3D-QSAR and the docking obtained in this study provide an insight into the understanding of the interactions between guanine derivatives and MGMT protein, which will assist in designing novel MGMT inhibitors with desired activity.
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Sun G, Zhang N, Zhao L, Fan T, Zhang S, Zhong R. Synthesis and antitumor activity evaluation of a novel combi-nitrosourea prodrug: Designed to release a DNA cross-linking agent and an inhibitor of O(6)-alkylguanine-DNA alkyltransferase. Bioorg Med Chem 2016; 24:2097-107. [PMID: 27041398 DOI: 10.1016/j.bmc.2016.03.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/22/2016] [Accepted: 03/25/2016] [Indexed: 10/22/2022]
Abstract
The drug resistance of CENUs induced by O(6)-alkylguanine-DNA alkyltransferase (AGT), which repairs the O(6)-alkylated guanine and subsequently inhibits the formation of dG-dC cross-links, hinders the application of CENU chemotherapies. Therefore, the discovery of CENU analogs with AGT inhibiting activity is a promising approach leading to novel CENU chemotherapies with high therapeutic index. In this study, a new combi-nitrosourea prodrug 3-(3-(((2-amino-9H-purin-6-yl)oxy)methyl)benzyl)-1-(2-chloroethyl)-1-nitrosourea (6), designed to release a DNA cross-linking agent and an inhibitor of AGT, was synthesized and evaluated for its antitumor activity and ability to induce DNA interstrand cross-links (ICLs). The results indicated that 6 exhibited higher cytotoxicity against mer(+) glioma cells compared with ACNU, BCNU, and their respective combinations with O(6)-benzylguanine (O(6)-BG). Quantifications of dG-dC cross-links induced by 6 were performed using HPLC-ESI-MS/MS. Higher levels of dG-dC cross-link were observed in 6-treated human glioma SF763 cells (mer(+)), whereas lower levels of dG-dC cross-link were observed in 6-treated calf thymus DNA, when compared with the groups treated with BCNU and ACNU. The results suggested that the superiority of 6 might result from the AGT inhibitory moiety, which specifically functions in cells with AGT activity. Molecular docking studies indicated that five hydrogen bonds were formed between the O(6)-BG analogs released from 6 and the five residues in the active pocket of AGT, which provided a reasonable explanation for the higher AGT-inhibitory activity of 6 than O(6)-BG.
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Affiliation(s)
- Guohui Sun
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, PR China
| | - Na Zhang
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, PR China
| | - Lijiao Zhao
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, PR China.
| | - Tengjiao Fan
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, PR China
| | - Shufen Zhang
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, PR China
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental & Viral Oncology, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, PR China
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Roy DK, Mondal B, Anju RS, Ghosh S. Back Cover: Chemistry of Diruthenium and Dirhodium Analogues of Pentaborane(9): Synthesis and Characterization of Metal N,S-Heterocyclic Carbene and B-Agostic Complexes (Chem. Eur. J. 9/2015). Chemistry 2015. [DOI: 10.1002/chem.404786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Nikkonen T, Oliva MM, Kahnt A, Muuronen M, Helaja J, Guldi DM. Photoinduced Charge Transfer in a Conformational Switching Chlorin Dimer-Azafulleroid in Polar and Nonpolar Media. Chemistry 2014; 21:590-600. [DOI: 10.1002/chem.201404786] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Indexed: 11/09/2022]
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Diversity oriented efficient access of trisubstituted purines via sequential regioselective Mitsunobu coupling and SNAr based C6 functionalizations. Tetrahedron 2013. [DOI: 10.1016/j.tet.2012.10.079] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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20
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Santiago DN, Pevzner Y, Durand AA, Tran M, Scheerer RR, Daniel K, Sung SS, Woodcock HL, Guida WC, Brooks WH. Virtual target screening: validation using kinase inhibitors. J Chem Inf Model 2012; 52:2192-203. [PMID: 22747098 PMCID: PMC3488111 DOI: 10.1021/ci300073m] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Computational methods involving virtual screening could potentially be employed to discover new biomolecular targets for an individual molecule of interest (MOI). However, existing scoring functions may not accurately differentiate proteins to which the MOI binds from a larger set of macromolecules in a protein structural database. An MOI will most likely have varying degrees of predicted binding affinities to many protein targets. However, correctly interpreting a docking score as a hit for the MOI docked to any individual protein can be problematic. In our method, which we term "Virtual Target Screening (VTS)", a set of small drug-like molecules are docked against each structure in the protein library to produce benchmark statistics. This calibration provides a reference for each protein so that hits can be identified for an MOI. VTS can then be used as tool for: drug repositioning (repurposing), specificity and toxicity testing, identifying potential metabolites, probing protein structures for allosteric sites, and testing focused libraries (collection of MOIs with similar chemotypes) for selectivity. To validate our VTS method, twenty kinase inhibitors were docked to a collection of calibrated protein structures. Here, we report our results where VTS predicted protein kinases as hits in preference to other proteins in our database. Concurrently, a graphical interface for VTS was developed.
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Affiliation(s)
- Daniel N. Santiago
- Department of Chemistry, University of South Florida, Tampa, Florida 33620
| | - Yuri Pevzner
- Department of Chemistry, University of South Florida, Tampa, Florida 33620
| | - Ashley A. Durand
- HTS & Chemistry Core, H. Lee Moffitt Cancer Institute & Research Institute, 12902 Magnolia Drive, Drug Discovery-SRB3, Tampa, Florida 33612
| | - MinhPhuong Tran
- Department of Chemistry, University of South Florida, Tampa, Florida 33620
| | - Rachel R. Scheerer
- Department of Chemistry, University of South Florida, Tampa, Florida 33620
| | - Kenyon Daniel
- HTS & Chemistry Core, H. Lee Moffitt Cancer Institute & Research Institute, 12902 Magnolia Drive, Drug Discovery-SRB3, Tampa, Florida 33612
| | - Shen-Shu Sung
- Department of Pharmacology, Milton S. Hershey Medical Cancer Institute, Pennsylvania State University, 500 University Drive, MC H072, Hershey, Pennsylvania 17033
| | - H. Lee Woodcock
- Department of Chemistry, University of South Florida, Tampa, Florida 33620
- Center for Molecular Diversity in Drug Design, Discovery and Delivery, University of South Florida, 4202 East Fowler Avenue, CHE 205, Tampa, Florida 33620
| | - Wayne C. Guida
- HTS & Chemistry Core, H. Lee Moffitt Cancer Institute & Research Institute, 12902 Magnolia Drive, Drug Discovery-SRB3, Tampa, Florida 33612
- Department of Chemistry, University of South Florida, Tampa, Florida 33620
- Center for Molecular Diversity in Drug Design, Discovery and Delivery, University of South Florida, 4202 East Fowler Avenue, CHE 205, Tampa, Florida 33620
| | - Wesley H. Brooks
- HTS & Chemistry Core, H. Lee Moffitt Cancer Institute & Research Institute, 12902 Magnolia Drive, Drug Discovery-SRB3, Tampa, Florida 33612
- Department of Chemistry, University of South Florida, Tampa, Florida 33620
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Zhu R, Seow HA, Baumann RP, Ishiguro K, Penketh PG, Shyam K, Sartorelli AC. Design of a hypoxia-activated prodrug inhibitor of O6-alkylguanine-DNA alkyltransferase. Bioorg Med Chem Lett 2012; 22:6242-7. [PMID: 22932317 DOI: 10.1016/j.bmcl.2012.08.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/24/2012] [Accepted: 08/01/2012] [Indexed: 11/15/2022]
Abstract
The efficacy of agents that alkylate the O-6 position of guanine is inhibited by O(6)-alkylguanine-DNA alkyltransferase (AGT) which removes these lesions from the tumor DNA. To increase differential toxicity, inhibitors must selectively deplete AGT in tumors, while sparing normal tissues where this protein serves a protective function. A newly synthesized prodrug of the AGT inhibitor O(6)-benzylguanine (O(6)-BG) with an α,α-dimethyl-4-nitrobenzyloxycarbonyl moiety masking the essential 2-amino group has demonstrated the feasibility of targeting hypoxic regions that are unique to solid tumors, for drug delivery. However, these modifications resulted in greatly decreased solubility. Recently, new potent global AGT inhibitors with improved formulatability such as O(6)-[(3-aminomethyl)benzylguanine (1) have been developed. However, acetylamino (N-(3-(((2-amino-9H-purin-6-yl)oxy)methyl)benzyl)acetamide) (2) exhibits a pronounced decrease in activity. Thus, 1 would be inactivated by N-acetylation and probably N-glucuronidation. To combat potential conjugational inactivation while retaining favorable solubility, we synthesized 6-((3-((dimethylamino)methyl)benzyl)oxy)-9H-purin-2-amine (3) in which the 3-aminomethyl moiety is protected by methylation; and to impart tumor selectivity we synthesized 2-(4-nitrophenyl)propan-2-yl(6-((3-((dimethylamino)methyl)benzyl)oxy)-9H-purin-2-yl)carbamate (7), a hypoxia targeted prodrug of 3 utilizing an α,α-dimethyl-4-nitrobenzyloxycarbonyl moiety. Consistent with this design, 7 demonstrates both hypoxia selective conversion by EMT6 cells of 7 to 3 and hypoxic sensitization of AGT containing DU145 cells to the cytotoxic actions of laromustine, while exhibiting improved solubility.
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Affiliation(s)
- Rui Zhu
- Department of Pharmacology and Developmental Therapeutics Program, Cancer Center, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8066, United States
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Uhlenheuer DA, Wasserberg D, Haase C, Nguyen HD, Schenkel JH, Huskens J, Ravoo BJ, Jonkheijm P, Brunsveld L. Directed Supramolecular Surface Assembly of SNAP-tag Fusion Proteins. Chemistry 2012; 18:6788-94. [DOI: 10.1002/chem.201200238] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Indexed: 02/04/2023]
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Li X, Qian S, Zheng L, Yang B, He Q, Hu Y. A mechanism-based fluorescent probe for labeling O6-methylguanine-DNA methyltransferase in live cells. Org Biomol Chem 2012; 10:3189-91. [DOI: 10.1039/c2ob25231g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pegg AE. Multifaceted roles of alkyltransferase and related proteins in DNA repair, DNA damage, resistance to chemotherapy, and research tools. Chem Res Toxicol 2011; 24:618-39. [PMID: 21466232 DOI: 10.1021/tx200031q] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
O(6)-Alkylguanine-DNA alkyltransferase (AGT) is a widely distributed, unique DNA repair protein that acts as a single agent to directly remove alkyl groups located on the O(6)-position of guanine from DNA restoring the DNA in one step. The protein acts only once, and its alkylated form is degraded rapidly. It is a major factor in counteracting the mutagenic, carcinogenic, and cytotoxic effects of agents that form such adducts including N-nitroso-compounds and a number of cancer chemotherapeutics. This review describes the structure, function, and mechanism of action of AGTs and of a family of related alkyltransferase-like proteins, which do not act alone to repair O(6)-alkylguanines in DNA but link repair to other pathways. The paradoxical ability of AGTs to stimulate the DNA-damaging ability of dihaloalkanes and other bis-electrophiles via the formation of AGT-DNA cross-links is also described. Other important properties of AGTs include the ability to provide resistance to cancer therapeutic alkylating agents, and the availability of AGT inhibitors such as O(6)-benzylguanine that might overcome this resistance is discussed. Finally, the properties of fusion proteins in which AGT sequences are linked to other proteins are outlined. Such proteins occur naturally, and synthetic variants engineered to react specifically with derivatives of O(6)-benzylguanine are the basis of a valuable research technique for tagging proteins with specific reagents.
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Affiliation(s)
- Anthony E Pegg
- Department of Cellular and Molecular Physiology, Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine , Pennsylvania 17033, United States.
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