The Experts below are selected from a list of 1074 Experts worldwide ranked by ideXlab platform
Matthew J Schellenberg - One of the best experts on this subject based on the ideXlab platform.
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zatt znf451 mediated resolution of topoisomerase 2 dna protein cross links
Science, 2017Co-Authors: Matthew J Schellenberg, Jenna Ariel Lieberman, Andres Herreroruiz, Logan R Butler, Jason Williams, Ana M Munozcabello, Geoffrey A Mueller, Robert E London, Felipe Cortesledesma, Scott R WilliamsAbstract:Topoisomerase 2 (TOP2) DNA transactions proceed via formation of the TOP2 cleavage complex (TOP2cc), a covalent enzyme-DNA reaction intermediate that is vulnerable to trapping by potent anticancer TOP2 drugs. How genotoxic TOP2 DNA-protein cross-links are resolved is unclear. We found that the SUMO (small ubiquitin-related modifier) ligase ZATT (ZNF451) is a multifunctional DNA repair factor that controls cellular responses to TOP2 damage. ZATT binding to TOP2cc facilitates a proteasome-independent tyrosyl-DNA Phosphodiesterase 2 (TDP2) hydrolase activity on stalled TOP2cc. The ZATT SUMO ligase activity further promotes TDP2 interactions with SUMOylated TOP2, regulating efficient TDP2 recruitment through a “split-SIM” SUMO2 engagement platform. These findings uncover a ZATT-TDP2–catalyzed and SUMO2-modulated pathway for direct resolution of TOP2cc.
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proteolytic degradation of topoisomerase ii top2 enables the processing of top2 dna and top2 rna covalent complexes by tyrosyl dna Phosphodiesterase 2 tdp2
Journal of Biological Chemistry, 2014Co-Authors: Matthew J Schellenberg, Christophe Marchand, John L. Nitiss, Shar Yin N Huang, Monica Abdelmalak, Karin C Nitiss, Scott R Williams, Yves PommierAbstract:Eukaryotic type II topoisomerases (Top2α and Top2β) are homodimeric enzymes; they are essential for altering DNA topology by the formation of normally transient double strand DNA cleavage. Anticancer drugs (etoposide, doxorubicin, and mitoxantrone) and also Top2 oxidation and DNA helical alterations cause potentially irreversible Top2·DNA cleavage complexes (Top2cc), leading to Top2-linked DNA breaks. Top2cc are the therapeutic mechanism for killing cancer cells. Yet Top2cc can also generate recombination, translocations, and apoptosis in normal cells. The Top2 protein-DNA covalent complexes are excised (in part) by tyrosyl-DNA-Phosphodiesterase 2 (TDP2/TTRAP/EAP2/VPg unlinkase). In this study, we show that irreversible Top2cc induced in suicidal substrates are not processed by TDP2 unless they first undergo proteolytic processing or denaturation. We also demonstrate that TDP2 is most efficient when the DNA attached to the tyrosyl is in a single-stranded configuration and that TDP2 can efficiently remove a tyrosine linked to a single misincorporated ribonucleotide or to polyribonucleotides, which expands the TDP2 catalytic profile with RNA substrates. The 1.6-Å resolution crystal structure of TDP2 bound to a substrate bearing a 5′-ribonucleotide defines a mechanism through which RNA can be accommodated in the TDP2 active site, albeit in a strained conformation.
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Proteolytic Degradation of Topoisomerase II (Top2) Enables the Processing of Top2·DNA and Top2·RNA Covalent Complexes by Tyrosyl-DNA-Phosphodiesterase 2 (TDP2)
The Journal of biological chemistry, 2014Co-Authors: Rui Gao, Christophe Marchand, John L. Nitiss, Matthew J Schellenberg, Shar Yin N Huang, Monica Abdelmalak, Karin C Nitiss, R. Scott Williams, Yves PommierAbstract:Eukaryotic type II topoisomerases (Top2α and Top2β) are homodimeric enzymes; they are essential for altering DNA topology by the formation of normally transient double strand DNA cleavage. Anticancer drugs (etoposide, doxorubicin, and mitoxantrone) and also Top2 oxidation and DNA helical alterations cause potentially irreversible Top2·DNA cleavage complexes (Top2cc), leading to Top2-linked DNA breaks. Top2cc are the therapeutic mechanism for killing cancer cells. Yet Top2cc can also generate recombination, translocations, and apoptosis in normal cells. The Top2 protein-DNA covalent complexes are excised (in part) by tyrosyl-DNA-Phosphodiesterase 2 (TDP2/TTRAP/EAP2/VPg unlinkase). In this study, we show that irreversible Top2cc induced in suicidal substrates are not processed by TDP2 unless they first undergo proteolytic processing or denaturation. We also demonstrate that TDP2 is most efficient when the DNA attached to the tyrosyl is in a single-stranded configuration and that TDP2 can efficiently remove a tyrosine linked to a single misincorporated ribonucleotide or to polyribonucleotides, which expands the TDP2 catalytic profile with RNA substrates. The 1.6-Å resolution crystal structure of TDP2 bound to a substrate bearing a 5′-ribonucleotide defines a mechanism through which RNA can be accommodated in the TDP2 active site, albeit in a strained conformation.
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mechanism of repair of 5 topoisomerase ii dna adducts by mammalian tyrosyl dna Phosphodiesterase 2
Nature Structural & Molecular Biology, 2012Co-Authors: Matthew J Schellenberg, Denise C Appel, Sanjay Adhikari, Patrick D Robertson, Dale A Ramsden, Scott R WilliamsAbstract:Tyrosyl-DNA Phosphodiesterase 2 (Tdp2) processes DNA termini with a 5′-phosphotyrosyl–linked topoisomerase II adduct, such as those stabilized by chemotherapeutic drugs anthracyclines and etoposides, by direct reversal of the 5′-phosphotyrosyl linkage. Now crystal structures of mouse Tdp2–DNA complexes, along with mutagenesis and functional analyses, reveal how Tdp2 recognizes and reverses such adduction.
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Mechanism of repair of 5′-topoisomerase II–DNA adducts by mammalian tyrosyl-DNA Phosphodiesterase 2
Nature Structural & Molecular Biology, 2012Co-Authors: Matthew J Schellenberg, Sanjay Adhikari, Patrick D Robertson, Dale A Ramsden, C. Denise Appel, R. Scott WilliamsAbstract:Tyrosyl-DNA Phosphodiesterase 2 (Tdp2) processes DNA termini with a 5′-phosphotyrosyl–linked topoisomerase II adduct, such as those stabilized by chemotherapeutic drugs anthracyclines and etoposides, by direct reversal of the 5′-phosphotyrosyl linkage. Now crystal structures of mouse Tdp2–DNA complexes, along with mutagenesis and functional analyses, reveal how Tdp2 recognizes and reverses such adduction. The topoisomerase II (topo II) DNA incision-and-ligation cycle can be poisoned (for example following treatment with cancer chemotherapeutics) to generate cytotoxic DNA double-strand breaks (DSBs) with topo II covalently conjugated to DNA. Tyrosyl-DNA Phosphodiesterase 2 (Tdp2) protects genomic integrity by reversing 5′-phosphotyrosyl–linked topo II – DNA adducts. Here, X-ray structures of mouse Tdp2–DNA complexes reveal that Tdp2 β–2-helix–β DNA damage–binding 'grasp', helical 'cap' and DNA lesion–binding elements fuse to form an elongated protein-DNA conjugate substrate-interaction groove. The Tdp2 DNA-binding surface is highly tailored for engagement of 5′-adducted single-stranded DNA ends and restricts nonspecific endonucleolytic or exonucleolytic processing. Structural, mutational and functional analyses support a single–metal ion catalytic mechanism for the exonuclease-endonuclease-phosphatase (EEP) nuclease superfamily and establish a molecular framework for targeted small-molecule blockade of Tdp2-mediated resistance to anticancer topoisomerase drugs.
R. Scott Williams - One of the best experts on this subject based on the ideXlab platform.
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Proteolytic Degradation of Topoisomerase II (Top2) Enables the Processing of Top2·DNA and Top2·RNA Covalent Complexes by Tyrosyl-DNA-Phosphodiesterase 2 (TDP2)
The Journal of biological chemistry, 2014Co-Authors: Rui Gao, Christophe Marchand, John L. Nitiss, Matthew J Schellenberg, Shar Yin N Huang, Monica Abdelmalak, Karin C Nitiss, R. Scott Williams, Yves PommierAbstract:Eukaryotic type II topoisomerases (Top2α and Top2β) are homodimeric enzymes; they are essential for altering DNA topology by the formation of normally transient double strand DNA cleavage. Anticancer drugs (etoposide, doxorubicin, and mitoxantrone) and also Top2 oxidation and DNA helical alterations cause potentially irreversible Top2·DNA cleavage complexes (Top2cc), leading to Top2-linked DNA breaks. Top2cc are the therapeutic mechanism for killing cancer cells. Yet Top2cc can also generate recombination, translocations, and apoptosis in normal cells. The Top2 protein-DNA covalent complexes are excised (in part) by tyrosyl-DNA-Phosphodiesterase 2 (TDP2/TTRAP/EAP2/VPg unlinkase). In this study, we show that irreversible Top2cc induced in suicidal substrates are not processed by TDP2 unless they first undergo proteolytic processing or denaturation. We also demonstrate that TDP2 is most efficient when the DNA attached to the tyrosyl is in a single-stranded configuration and that TDP2 can efficiently remove a tyrosine linked to a single misincorporated ribonucleotide or to polyribonucleotides, which expands the TDP2 catalytic profile with RNA substrates. The 1.6-Å resolution crystal structure of TDP2 bound to a substrate bearing a 5′-ribonucleotide defines a mechanism through which RNA can be accommodated in the TDP2 active site, albeit in a strained conformation.
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Mechanism of repair of 5′-topoisomerase II–DNA adducts by mammalian tyrosyl-DNA Phosphodiesterase 2
Nature Structural & Molecular Biology, 2012Co-Authors: Matthew J Schellenberg, Sanjay Adhikari, Patrick D Robertson, Dale A Ramsden, C. Denise Appel, R. Scott WilliamsAbstract:Tyrosyl-DNA Phosphodiesterase 2 (Tdp2) processes DNA termini with a 5′-phosphotyrosyl–linked topoisomerase II adduct, such as those stabilized by chemotherapeutic drugs anthracyclines and etoposides, by direct reversal of the 5′-phosphotyrosyl linkage. Now crystal structures of mouse Tdp2–DNA complexes, along with mutagenesis and functional analyses, reveal how Tdp2 recognizes and reverses such adduction. The topoisomerase II (topo II) DNA incision-and-ligation cycle can be poisoned (for example following treatment with cancer chemotherapeutics) to generate cytotoxic DNA double-strand breaks (DSBs) with topo II covalently conjugated to DNA. Tyrosyl-DNA Phosphodiesterase 2 (Tdp2) protects genomic integrity by reversing 5′-phosphotyrosyl–linked topo II – DNA adducts. Here, X-ray structures of mouse Tdp2–DNA complexes reveal that Tdp2 β–2-helix–β DNA damage–binding 'grasp', helical 'cap' and DNA lesion–binding elements fuse to form an elongated protein-DNA conjugate substrate-interaction groove. The Tdp2 DNA-binding surface is highly tailored for engagement of 5′-adducted single-stranded DNA ends and restricts nonspecific endonucleolytic or exonucleolytic processing. Structural, mutational and functional analyses support a single–metal ion catalytic mechanism for the exonuclease-endonuclease-phosphatase (EEP) nuclease superfamily and establish a molecular framework for targeted small-molecule blockade of Tdp2-mediated resistance to anticancer topoisomerase drugs.
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Mechanism of repair of 5′-topoisomerase II–DNA adducts by mammalian tyrosyl-DNA Phosphodiesterase 2
Nature structural & molecular biology, 2012Co-Authors: Matthew J Schellenberg, Sanjay Adhikari, Patrick D Robertson, Dale A Ramsden, C. Denise Appel, R. Scott WilliamsAbstract:Tyrosyl-DNA Phosphodiesterase 2 (Tdp2) processes DNA termini with a 5′-phosphotyrosyl–linked topoisomerase II adduct, such as those stabilized by chemotherapeutic drugs anthracyclines and etoposides, by direct reversal of the 5′-phosphotyrosyl linkage. Now crystal structures of mouse Tdp2–DNA complexes, along with mutagenesis and functional analyses, reveal how Tdp2 recognizes and reverses such adduction.
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Development of a novel assay for human tyrosyl DNA Phosphodiesterase 2.
Analytical biochemistry, 2011Co-Authors: Sanjay Adhikari, R. Scott Williams, Soumendra K. Karmahapatra, Hadi Elias, Priyanka Dhopeshwarkar, Stephen W. Byers, Aykut Üren, Rabindra RoyAbstract:Abstract Tyrosyl DNA Phosphodiesterase 2 (TDP2), a newly discovered enzyme that cleaves 5′-phosphotyrosyl bonds, is a potential target for chemotherapy. TDP2 possesses both 3′- and 5′-tyrosyl-DNA Phosphodiesterase activity, which is generally measured in a gel-based assay using 3′- and 5′-phosphotyrosyl linkage at the 3′ and 5′ ends of an oligonucleotide. To understand the enzymatic mechanism of this novel enzyme, the gel-based assay is useful, but this technique is cumbersome for TDP2 inhibitor screening. For this reason, we have designed a novel assay using p -nitrophenyl-thymidine-5′-phosphate (T5PNP) as a substrate. This assay can be used in continuous colorimetric assays in a 96-well format. We compared the salt and pH effect on product formation with the colorimetric and gel-based assays and showed that they behave similarly. Steady-state kinetic studies showed that the 5′ activity of TDP2 is 1000-fold more efficient than T5PNP. Tyrosyl DNA Phosphodiesterase 1 (TDP1) and human AP-endonuclease 1 (APE1) could not hydrolyze T5PNP. Sodium orthovanadate, a known inhibitor of TDP2, inhibits product formation from T5PNP by TDP2 (IC 50 = 40 mM). Our results suggest that this novel assay system with this new TDP2 substrate can be used for inhibitor screening in a high-throughput manner.
Yves Pommier - One of the best experts on this subject based on the ideXlab platform.
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Novel deazaflavin tyrosyl-DNA Phosphodiesterase 2 (TDP2) inhibitors.
DNA repair, 2019Co-Authors: Evgeny Kiselev, Jayakanth Kankanala, Jiashu Xie, Zhengqiang Wang, Azhar Ravji, Yves PommierAbstract:Abstract Tyrosyl-DNA Phosphodiesterase 2 (TDP2) is a DNA repair enzyme that removes 5′-phosphotyrosyl blockages resulting from topoisomerase II (TOP2)-DNA cleavage complexes trapped by TOP2 inhibitors. TDP2 is a logical target for the development of therapeutics to complement existing treatments based on inhibition of TOP2. There is, however, no TDP2 inhibitor in clinical development at present. Of the reported TDP2 inhibitors, the deazaflavins are the most promising chemical class centered around the lead compound SV-5-153. Recently we reported new subtypes derived within the deazaflavin family with improved membrane permeability properties. In this work we characterize two representative analogues from two new deazaflavin subtypes based on their biochemical TDP2 inhibitory potency and drug-likeness. We demonstrate that the ZW-1288 derivative represents a promising direction for the development of deazaflavins as therapeutic agents. ZW-1288 exhibits potent inhibitory activity at low nanomolar concentrations against recombinant and cellular human TDP2 with profile similar to that of the parent analog SV-5-153 based on high resistance against murine TDP2 and human TDP2 mutated at residue L313H. While expressing weak cytotoxicity on its own, ZW-1288 potentiates the clinical TOP2 inhibitors etoposide (ETP) and mitoxantrone in human prostate DU145 and CCRF-CEM leukemia and chicken lymphoma DT40 cells while not impacting the activity of the topoisomerase I (TOP1) inhibitor camptothecin or the PARP inhibitor olaparib. ZW-1288 increases the uptake of ETP to a lesser extent than SV-5-153 and remained active in TDP2 knockout cells indicating that the deazaflavin TDP2 inhibitors have additional cellular effects that will have to be taken into account for their further development as TDP2 inhibitors.
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Novel Deazaflavin Analogues Potently Inhibited Tyrosyl DNA Phosphodiesterase 2 (TDP2) and Strongly Sensitized Cancer Cells toward Treatment with Topoisomerase II (TOP2) Poison Etoposide.
Journal of medicinal chemistry, 2019Co-Authors: Jayakanth Kankanala, Yves Pommier, Carlos Ribeiro, Jiashu Xie, Jessica Williams, Hideki Aihara, Azhar Ravji, Evgeny Kiselev, Zhengqiang WangAbstract:Topoisomerase II (TOP2) poisons as anticancer drugs work by trapping TOP2 cleavage complexes (TOP2cc) to generate DNA damage. Repair of such damage by tyrosyl DNA Phosphodiesterase 2 (TDP2) could render cancer cells resistant to TOP2 poisons. Inhibiting TDP2, thus, represents an attractive mechanism-based chemosensitization approach. Currently known TDP2 inhibitors lack cellular potency and/or permeability. We report herein two novel subtypes of the deazaflavin TDP2 inhibitor core. By introducing an additional phenyl ring to the N-10 phenyl ring (subtype 11) or to the N-3 site of the deazaflavin scaffold (subtype 12), we have generated novel analogues with considerably improved biochemical potency and/or permeability. Importantly, many analogues of both subtypes, particularly compounds 11a, 11e, 12a, 12b, and 12h, exhibited much stronger cancer cell sensitizing effect than the best previous analogue 4a toward the treatment with etoposide, suggesting that these analogues could serve as effective cellular probes.
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Novel Deazaflavin Analogues Potently Inhibited Tyrosyl DNA Phosphodiesterase 2 (TDP2) and Strongly Sensitized Cancer Cells toward Treatment with Topoisomerase II (TOP2) Poison Etoposide
2019Co-Authors: Jayakanth Kankanala, Yves Pommier, Jiashu Xie, Jessica Williams, Hideki Aihara, Azhar Ravji, Evgeny Kiselev, Carlos J. A. Ribeiro, Zhengqiang WangAbstract:Topoisomerase II (TOP2) poisons as anticancer drugs work by trapping TOP2 cleavage complexes (TOP2cc) to generate DNA damage. Repair of such damage by tyrosyl DNA Phosphodiesterase 2 (TDP2) could render cancer cells resistant to TOP2 poisons. Inhibiting TDP2, thus, represents an attractive mechanism-based chemosensitization approach. Currently known TDP2 inhibitors lack cellular potency and/or permeability. We report herein two novel subtypes of the deazaflavin TDP2 inhibitor core. By introducing an additional phenyl ring to the N-10 phenyl ring (subtype 11) or to the N-3 site of the deazaflavin scaffold (subtype 12), we have generated novel analogues with considerably improved biochemical potency and/or permeability. Importantly, many analogues of both subtypes, particularly compounds 11a, 11e, 12a, 12b, and 12h, exhibited much stronger cancer cell sensitizing effect than the best previous analogue 4a toward the treatment with etoposide, suggesting that these analogues could serve as effective cellular probes
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New fluorescence-based high-throughput screening assay for small molecule inhibitors of tyrosyl-DNA Phosphodiesterase 2 (TDP2).
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2018Co-Authors: Carlos Ribeiro, Yves Pommier, Jayakanth Kankanala, Hideki Aihara, Azhar Ravji, Evgeny Kiselev, Kayo Kurahashi, Ke Shi, Zhengqiang WangAbstract:Abstract Tyrosyl-DNA Phosphodiesterase 2 (TDP2) repairs topoisomerase II (TOP2) mediated DNA damages and causes resistance to TOP2-targeted cancer therapy. Inhibiting TDP2 could sensitize cancer cells toward TOP2 inhibitors. However, potent TDP2 inhibitors with favorable physicochemical properties are not yet reported. Therefore, there is a need to search for novel molecular scaffolds capable of inhibiting TDP2. We report herein a new simple, robust, homogenous mix-and-read fluorescence biochemical assay based using humanized zebrafish TDP2 (14M_zTDP2), which provides biochemical and molecular structure basis for TDP2 inhibitor discovery. The assay was validated by screening a preselected library of 1600 compounds (Z′ ≥ 0.72) in a 384-well format, and by running in parallel gel-based assays with fluorescent DNA substrates. This library was curated via virtual high throughput screening (vHTS) of 460,000 compounds from Chembridge Library, using the crystal structure of the novel surrogate protein 14M_zTDP2. From this primary screening, we selected the best 32 compounds (2% of the library) to further assess their TDP2 inhibition potential, leading to the IC50 determination of 10 compounds. Based on the dose-response curve profile, pan-assay interference compounds (PAINS) structure identification, physicochemical properties and efficiency parameters, two hit compounds, 11a and 19a, were tested using a novel secondary fluorescence gel-based assay. Preliminary structure-activity relationship (SAR) studies identified guanidine derivative 12a as an improved hit with a 6.4-fold increase in potency over the original HTS hit 11a. This study highlights the importance of the development of combination approaches (biochemistry, crystallography and high throughput screening) for the discovery of TDP2 inhibitors.
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Discovery of selective inhibitors of tyrosyl-DNA Phosphodiesterase 2 by targeting the enzyme DNA-binding cleft.
Bioorganic & medicinal chemistry letters, 2016Co-Authors: Bradley R. Kossmann, Yves Pommier, Christophe Marchand, Monica Abdelmalak, Sophia Lopez, Gabrielle S. Tender, Chunli Yan, Ivaylo IvanovAbstract:Tyrosyl-DNA Phosphodiesterase 2 (TDP2) processes protein/DNA adducts resulting from abortive DNA topoisomerase II (Top2) activity. TDP2 inhibition could provide synergism with the Top2 poison class of chemotherapeutics. By virtual screening of the NCI diversity small molecule database, we identified selective TDP2 inhibitors and experimentally verified their selective inhibitory activity. Three inhibitors exhibited low-micromolar IC50 values. Molecular dynamics simulations revealed a common binding mode for these inhibitors, involving association to the TDP2 DNA-binding cleft. MM-PBSA per-residue energy decomposition identified important interactions of the compounds with specific TDP2 residues. These interactions could provide new avenues for synthetic optimization of these scaffolds.
Sanjay Adhikari - One of the best experts on this subject based on the ideXlab platform.
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mechanism of repair of 5 topoisomerase ii dna adducts by mammalian tyrosyl dna Phosphodiesterase 2
Nature Structural & Molecular Biology, 2012Co-Authors: Matthew J Schellenberg, Denise C Appel, Sanjay Adhikari, Patrick D Robertson, Dale A Ramsden, Scott R WilliamsAbstract:Tyrosyl-DNA Phosphodiesterase 2 (Tdp2) processes DNA termini with a 5′-phosphotyrosyl–linked topoisomerase II adduct, such as those stabilized by chemotherapeutic drugs anthracyclines and etoposides, by direct reversal of the 5′-phosphotyrosyl linkage. Now crystal structures of mouse Tdp2–DNA complexes, along with mutagenesis and functional analyses, reveal how Tdp2 recognizes and reverses such adduction.
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Mechanism of repair of 5′-topoisomerase II–DNA adducts by mammalian tyrosyl-DNA Phosphodiesterase 2
Nature Structural & Molecular Biology, 2012Co-Authors: Matthew J Schellenberg, Sanjay Adhikari, Patrick D Robertson, Dale A Ramsden, C. Denise Appel, R. Scott WilliamsAbstract:Tyrosyl-DNA Phosphodiesterase 2 (Tdp2) processes DNA termini with a 5′-phosphotyrosyl–linked topoisomerase II adduct, such as those stabilized by chemotherapeutic drugs anthracyclines and etoposides, by direct reversal of the 5′-phosphotyrosyl linkage. Now crystal structures of mouse Tdp2–DNA complexes, along with mutagenesis and functional analyses, reveal how Tdp2 recognizes and reverses such adduction. The topoisomerase II (topo II) DNA incision-and-ligation cycle can be poisoned (for example following treatment with cancer chemotherapeutics) to generate cytotoxic DNA double-strand breaks (DSBs) with topo II covalently conjugated to DNA. Tyrosyl-DNA Phosphodiesterase 2 (Tdp2) protects genomic integrity by reversing 5′-phosphotyrosyl–linked topo II – DNA adducts. Here, X-ray structures of mouse Tdp2–DNA complexes reveal that Tdp2 β–2-helix–β DNA damage–binding 'grasp', helical 'cap' and DNA lesion–binding elements fuse to form an elongated protein-DNA conjugate substrate-interaction groove. The Tdp2 DNA-binding surface is highly tailored for engagement of 5′-adducted single-stranded DNA ends and restricts nonspecific endonucleolytic or exonucleolytic processing. Structural, mutational and functional analyses support a single–metal ion catalytic mechanism for the exonuclease-endonuclease-phosphatase (EEP) nuclease superfamily and establish a molecular framework for targeted small-molecule blockade of Tdp2-mediated resistance to anticancer topoisomerase drugs.
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Mechanism of repair of 5′-topoisomerase II–DNA adducts by mammalian tyrosyl-DNA Phosphodiesterase 2
Nature structural & molecular biology, 2012Co-Authors: Matthew J Schellenberg, Sanjay Adhikari, Patrick D Robertson, Dale A Ramsden, C. Denise Appel, R. Scott WilliamsAbstract:Tyrosyl-DNA Phosphodiesterase 2 (Tdp2) processes DNA termini with a 5′-phosphotyrosyl–linked topoisomerase II adduct, such as those stabilized by chemotherapeutic drugs anthracyclines and etoposides, by direct reversal of the 5′-phosphotyrosyl linkage. Now crystal structures of mouse Tdp2–DNA complexes, along with mutagenesis and functional analyses, reveal how Tdp2 recognizes and reverses such adduction.
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Development of a novel assay for human tyrosyl DNA Phosphodiesterase 2.
Analytical biochemistry, 2011Co-Authors: Sanjay Adhikari, R. Scott Williams, Soumendra K. Karmahapatra, Hadi Elias, Priyanka Dhopeshwarkar, Stephen W. Byers, Aykut Üren, Rabindra RoyAbstract:Abstract Tyrosyl DNA Phosphodiesterase 2 (TDP2), a newly discovered enzyme that cleaves 5′-phosphotyrosyl bonds, is a potential target for chemotherapy. TDP2 possesses both 3′- and 5′-tyrosyl-DNA Phosphodiesterase activity, which is generally measured in a gel-based assay using 3′- and 5′-phosphotyrosyl linkage at the 3′ and 5′ ends of an oligonucleotide. To understand the enzymatic mechanism of this novel enzyme, the gel-based assay is useful, but this technique is cumbersome for TDP2 inhibitor screening. For this reason, we have designed a novel assay using p -nitrophenyl-thymidine-5′-phosphate (T5PNP) as a substrate. This assay can be used in continuous colorimetric assays in a 96-well format. We compared the salt and pH effect on product formation with the colorimetric and gel-based assays and showed that they behave similarly. Steady-state kinetic studies showed that the 5′ activity of TDP2 is 1000-fold more efficient than T5PNP. Tyrosyl DNA Phosphodiesterase 1 (TDP1) and human AP-endonuclease 1 (APE1) could not hydrolyze T5PNP. Sodium orthovanadate, a known inhibitor of TDP2, inhibits product formation from T5PNP by TDP2 (IC 50 = 40 mM). Our results suggest that this novel assay system with this new TDP2 substrate can be used for inhibitor screening in a high-throughput manner.
Monica Abdelmalak - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and structure-activity relationship of furoquinolinediones as inhibitors of Tyrosyl-DNA Phosphodiesterase 2 (TDP2).
European journal of medicinal chemistry, 2018Co-Authors: Yu Chen, Monica Abdelmalak, Azhar Ravji, Sophia Lopez, Caroline B. Plescia, Hui Yang, Sourav SahaAbstract:Tyrosyl-DNA Phosphodiesterase 2 (TDP2) is a recently discovered enzyme specifically repairing topoisomerase II (TOP2)-mediated DNA damage. It has been shown that inhibition of TDP2 synergize with TOP2 inhibitors. Herein, we report the discovery of the furoquinolinedione chemotype as a suitable skeleton for the development of selective TDP2 inhibitors. Compound 1 was identified as a TDP2 inhibitor as a result of screening our in-house compound library for compounds selective for TDP2 vs. TDP1. Further SAR studies provide several selective TDP2 inhibitors at low-micromolar range. The most potent compound 74 shows inhibitory activity with IC50 of 1.9 and 2.1 μM against recombinant TDP2 and TDP2 in whole cell extracts (WCE), respectively.
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Discovery of selective inhibitors of tyrosyl-DNA Phosphodiesterase 2 by targeting the enzyme DNA-binding cleft.
Bioorganic & medicinal chemistry letters, 2016Co-Authors: Bradley R. Kossmann, Yves Pommier, Christophe Marchand, Monica Abdelmalak, Sophia Lopez, Gabrielle S. Tender, Chunli Yan, Ivaylo IvanovAbstract:Tyrosyl-DNA Phosphodiesterase 2 (TDP2) processes protein/DNA adducts resulting from abortive DNA topoisomerase II (Top2) activity. TDP2 inhibition could provide synergism with the Top2 poison class of chemotherapeutics. By virtual screening of the NCI diversity small molecule database, we identified selective TDP2 inhibitors and experimentally verified their selective inhibitory activity. Three inhibitors exhibited low-micromolar IC50 values. Molecular dynamics simulations revealed a common binding mode for these inhibitors, involving association to the TDP2 DNA-binding cleft. MM-PBSA per-residue energy decomposition identified important interactions of the compounds with specific TDP2 residues. These interactions could provide new avenues for synthetic optimization of these scaffolds.
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Deazaflavin Inhibitors of Tyrosyl-DNA Phosphodiesterase 2 (TDP2) Specific for the Human Enzyme and Active against Cellular TDP2.
ACS chemical biology, 2016Co-Authors: Christophe Marchand, Monica Abdelmalak, Jayakanth Kankanala, Shar-yin Huang, Evgeny Kiselev, Katherine Fesen, Kayo Kurahashi, Hiroyuki Sasanuma, Shunichi Takeda, Hideki AiharaAbstract:Tyrosyl-DNA Phosphodiesterase 2 repairs irreversible topoisomerase II-mediated cleavage complexes generated by anticancer topoisomerase-targeted drugs and processes replication intermediates for picornaviruses (VPg unlinkase) and hepatitis B virus. There is currently no TDP2 inhibitor in clinical development. Here, we report a series of deazaflavin derivatives that selectively inhibit the human TDP2 enzyme in a competitive manner both with recombinant and native TDP2. We show that mouse, fish, and C. elegans TDP2 enzymes are highly resistant to the drugs and that key protein residues are responsible for drug resistance. Among them, human residues L313 and T296 confer high resistance when mutated to their mouse counterparts. Moreover, deazaflavin derivatives show potent synergy in combination with the topoisomerase II inhibitor etoposide in human prostate cancer DU145 cells and TDP2-dependent synergy in TK6 human lymphoblast and avian DT40 cells. Deazaflavin derivatives represent the first suitable platfor...
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proteolytic degradation of topoisomerase ii top2 enables the processing of top2 dna and top2 rna covalent complexes by tyrosyl dna Phosphodiesterase 2 tdp2
Journal of Biological Chemistry, 2014Co-Authors: Matthew J Schellenberg, Christophe Marchand, John L. Nitiss, Shar Yin N Huang, Monica Abdelmalak, Karin C Nitiss, Scott R Williams, Yves PommierAbstract:Eukaryotic type II topoisomerases (Top2α and Top2β) are homodimeric enzymes; they are essential for altering DNA topology by the formation of normally transient double strand DNA cleavage. Anticancer drugs (etoposide, doxorubicin, and mitoxantrone) and also Top2 oxidation and DNA helical alterations cause potentially irreversible Top2·DNA cleavage complexes (Top2cc), leading to Top2-linked DNA breaks. Top2cc are the therapeutic mechanism for killing cancer cells. Yet Top2cc can also generate recombination, translocations, and apoptosis in normal cells. The Top2 protein-DNA covalent complexes are excised (in part) by tyrosyl-DNA-Phosphodiesterase 2 (TDP2/TTRAP/EAP2/VPg unlinkase). In this study, we show that irreversible Top2cc induced in suicidal substrates are not processed by TDP2 unless they first undergo proteolytic processing or denaturation. We also demonstrate that TDP2 is most efficient when the DNA attached to the tyrosyl is in a single-stranded configuration and that TDP2 can efficiently remove a tyrosine linked to a single misincorporated ribonucleotide or to polyribonucleotides, which expands the TDP2 catalytic profile with RNA substrates. The 1.6-Å resolution crystal structure of TDP2 bound to a substrate bearing a 5′-ribonucleotide defines a mechanism through which RNA can be accommodated in the TDP2 active site, albeit in a strained conformation.
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Proteolytic Degradation of Topoisomerase II (Top2) Enables the Processing of Top2·DNA and Top2·RNA Covalent Complexes by Tyrosyl-DNA-Phosphodiesterase 2 (TDP2)
The Journal of biological chemistry, 2014Co-Authors: Rui Gao, Christophe Marchand, John L. Nitiss, Matthew J Schellenberg, Shar Yin N Huang, Monica Abdelmalak, Karin C Nitiss, R. Scott Williams, Yves PommierAbstract:Eukaryotic type II topoisomerases (Top2α and Top2β) are homodimeric enzymes; they are essential for altering DNA topology by the formation of normally transient double strand DNA cleavage. Anticancer drugs (etoposide, doxorubicin, and mitoxantrone) and also Top2 oxidation and DNA helical alterations cause potentially irreversible Top2·DNA cleavage complexes (Top2cc), leading to Top2-linked DNA breaks. Top2cc are the therapeutic mechanism for killing cancer cells. Yet Top2cc can also generate recombination, translocations, and apoptosis in normal cells. The Top2 protein-DNA covalent complexes are excised (in part) by tyrosyl-DNA-Phosphodiesterase 2 (TDP2/TTRAP/EAP2/VPg unlinkase). In this study, we show that irreversible Top2cc induced in suicidal substrates are not processed by TDP2 unless they first undergo proteolytic processing or denaturation. We also demonstrate that TDP2 is most efficient when the DNA attached to the tyrosyl is in a single-stranded configuration and that TDP2 can efficiently remove a tyrosine linked to a single misincorporated ribonucleotide or to polyribonucleotides, which expands the TDP2 catalytic profile with RNA substrates. The 1.6-Å resolution crystal structure of TDP2 bound to a substrate bearing a 5′-ribonucleotide defines a mechanism through which RNA can be accommodated in the TDP2 active site, albeit in a strained conformation.