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David E. Thurston - One of the best experts on this subject based on the ideXlab platform.
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Topical delivery of Anthramycin I. Influence of neat solvents
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2017Co-Authors: Tasnuva Haque, David E. Thurston, Khondaker M. Rahman, Jonathan Hadgraft, Majella E. LaneAbstract:Anthramycin (ANT) was the first pyrrolobenzodiazepine (PBD) molecule to be isolated, and is a potent cytotoxic agent. Although the PBD family has been investigated for use in systemic chemotherapy, their application in the management of actinic keratoses (AK) or skin cancer has not been investigated to date. In the present work, Anthramycin (ANT) was selected as a model PBD compound, and the skin penetration of the molecule was investigated using conventional Franz diffusion cells. Finite dose permeation studies of ANT were performed using propylene glycol (PG), 1,3-butanediol (BD), dipropylene glycol (DiPG), Transcutol P® (TC), propylene glycol monocaprylate (PGMC), propylene glycol monolaurate (PGML) and isopropyl myristate (IPM). The skin penetration of BD, DiPG, PG and TC was also measured. Penetration of ANT through human skin was evident for TC, PG and PGML with the active appearing to "track" the permeation of the vehicle in the case of TC and PG. Deposition of ANT in skin could be correlated with skin retention of the vehicle in the case of IPM, PGMC and PGML. These preliminary findings confirm the ability of ANT to penetrate human skin and, given the potency of the molecule, suggest that further investigation is justified. Additionally, the findings emphasise the critical importance of understanding the fate of the excipient for the rational design of topical formulations.
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entwicklung pyrrolobenzodiazepin pbd haltiger antikorper wirkstoff konjugate adcs ausgehend von Anthramycin
Angewandte Chemie, 2017Co-Authors: Julia Mantaj, Paul J. M. Jackson, Khondaker M. Rahman, David E. ThurstonAbstract:Die Pyrrolo[2,1-c][1,4]benzodiazepine (PBDs) sind eine Familie sequenzselektiver Wirkstoffe, die an die kleine Furche der DNA binden und eine kovalente Aminalbindung zwischen der C11-Position und den C2-NH2-Gruppen der Guaninbasen bilden. Anthramycin ist das erste Beispiel eines PBD-Monomers und wurde in den 1960er Jahren entdeckt. In den 1990er Jahren wurde das bekannteste PBD-Dimer SJG-136 entwickelt und hat jetzt bereits die klinischen Studien der Phase II in Patienten mit Leukamie und Eierstockkrebs durchlaufen. Seit kurzem werden aus PBD-Dimeranaloga und spezifisch an Tumorzellen bindenden Antikorpern Antikorper-Wirkstoff-Konjugate (ADCs) hergestellt. Von diesen befinden sich derzeit mehrere in klinischen Studien und viele andere in der praklinischen Entwicklung. Dieser Aufsatz zeigt die Entwicklung der PBDs ausgehend von Anthramycin uber die ersten PBD-Dimere bis hin zu PBD-haltigen ADCs und behandelt sowohl die Struktur-Wirkungs-Beziehungen und die Biologie der PBDs als auch die Strategien fur ihre Verwendung als Wirkstoffkomponente in ADCs.
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From Anthramycin to Pyrrolobenzodiazepine (PBD)-Containing Antibody-Drug Conjugates (ADCs).
Angewandte Chemie (International ed. in English), 2016Co-Authors: Julia Mantaj, Paul J. M. Jackson, Khondaker M. Rahman, David E. ThurstonAbstract:The pyrrolo[2,1-c][1,4]benzodiazepines (PBDs) are a family of sequence-selective DNA minor-groove binding agents that form a covalent aminal bond between their C11-position and the C2-NH2 groups of guanine bases. The first example of a PBD monomer, the natural product Anthramycin, was discovered in the 1960s, and the best known PBD dimer, SJG-136 (also known as SG2000, NSC 694501 or BN2629), was synthesized in the 1990s and has recently completed Phase II clinical trials in patients with leukaemia and ovarian cancer. More recently, PBD dimer analogues are being attached to tumor-targeting antibodies to create antibody-drug conjugates (ADCs), a number of which are now in clinical trials, with many others in pre-clinical development. This Review maps the development from Anthramycin to the first PBD dimers, and then to PBD-containing ADCs, and explores both structure-activity relationships (SARs) and the biology of PBDs, and the strategies for their use as payloads for ADCs.
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Structures of PBDs used in this study.
2016Co-Authors: Julia Mantaj, Paul J. M. Jackson, Kersti Karu, Khondaker M. Rahman, David E. ThurstonAbstract:The naturally occurring Anthramycin as its C11-methyl ether (1), the synthetic PBD Dimer SJG-136 (2), and the synthetic C8-bis-pyrrole PBD Conjugate GWL-78 (3).
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Pyrrolobenzodiazepines (PBDs) Do Not Bind to DNA G-Quadruplexes - Figure 5
2014Co-Authors: Khondaker M. Rahman, Paul J. M. Jackson, David B. Corcoran, Tam T. T. Bui, David E. ThurstonAbstract:A & B, CD titration of Anthramycin (1) and the C8-PBD-morpholine (3), respectively, with the telomeric G-quadruplex sequence (HT4) demonstrating a lack of interaction; C & D, CD melting profile of Anthramycin:HT4 and C8-PBD-morpholine (3):HT4, respectively. For both molecules there was no change in CD melting temperature compared to the HT4 DNA alone.
Brian O. Bachmann - One of the best experts on this subject based on the ideXlab platform.
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Adenylation Enzyme Characterization Using γ -18O4-ATP Pyrophosphate Exchange
Chemistry & biology, 2009Co-Authors: Vanessa V. Phelan, John A. Mclean, Brian O. BachmannAbstract:We present here a rapid, highly sensitive nonradioactive assay for adenylation enzyme selectivity determination and characterization. This method measures the isotopic back exchange of unlabeled pyrophosphate into gamma-(18)O(4)-labeled ATP via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS), electrospray ionization liquid chromatography MS, or electrospray ionization liquid chromatography-tandem MS and is demonstrated for both nonribosomal (TycA, ValA) and ribosomal synthetases (TrpRS, LysRS) of known specificity. This low-volume (6 microl) method detects as little as 0.01% (600 fmol) exchange, comparable in sensitivity to previously reported radioactive assays and readily adaptable to kinetics measurements and high throughput analysis of a wide spectrum of synthetases. Finally, a previously uncharacterized A-T didomain from Anthramycin biosynthesis in the thermophile S. refuinius was demonstrated to selectively activate 4-methyl-3-hydroxyanthranilic acid at 47 degrees C, providing biochemical evidence for a new aromatic beta-amino acid activating adenylation domain and the first functional analysis of the Anthramycin biosynthetic gene cluster.
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Reassembly of Anthramycin Biosynthetic Gene Cluster by Using Recombinogenic Cassettes
Chembiochem : a European journal of chemical biology, 2008Co-Authors: Vanessa V. Phelan, Chris M. Farnet, Emmanuel Zazopoulos, Brian O. BachmannAbstract:The reassembly and heterologous expression of complete gene clusters in shuttle vectors has enabled investigations of several large biosynthetic pathways in recent years. With a gene cluster in a mobile construct, the interrogation of gene functions from both culturable and nonculturable organisms is greatly accelerated and large pathway engineering efforts can be executed to produce "new" natural products. However, the genetic manipulation of complete natural product biosynthetic gene clusters is often complicated by their sheer size (10-200 kbp), which makes standard restriction/ligation-based methods impracticable. To circumvent these problems, alternative recombinogenic methods, which depend on engineered homology-based recombination have recently arisen as a powerful alternative. Here, we describe a new general technique that can be used to reconstruct large biosynthetic pathways from overlapping cosmids by retrofitting each cosmid with a "recombinogenic cassette" that contains a shared homologous element and orthogonal antibiotic markers. We employed this technique to reconstruct the Anthramycin biosynthetic gene cluster of the thermotolerant actinomycete Streptomyces refuineus, from two >30 kbp cosmids into a single cosmid and integrate it into the genome of Streptomyces lividans. Anthramycin production in the heterologous Streptomyces host confirmed the integrity of the reconstructed pathway and validated the proposed boundaries of the gene cluster. Notably, Anthramycin production by recombinant S. lividans was seen only during growth at high temperature--a property also shown by the natural host. This work provides tools to engineer the Anthramycin biosynthetic pathway and to explore the connection between Anthramycin production and growth at elevated temperatures.
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Benzodiazepine Biosynthesis in Streptomyces refuineus
Chemistry & biology, 2007Co-Authors: Vanessa V. Phelan, Ioanna Ntai, Chris M. Farnet, Emmanuel Zazopoulos, Brian O. BachmannAbstract:Summary Anthramycin is a benzodiazepine alkaloid with potent antitumor and antibiotic activity produced by the thermophilic actinomycete Streptomyces refuineus sbsp. thermotolerans . In this study, the complete 32.5 kb gene cluster for the biosynthesis of Anthramycin was identified by using a genome-scanning approach, and cluster boundaries were estimated via comparative genomics. A λ-RED-mediated gene-replacement system was developed to provide supporting evidence for critical biosynthetic genes and to validate the boundaries of the proposed Anthramycin gene cluster. Sequence analysis reveals that the 25 open reading frame Anthramycin cluster contains genes consistent with the biosynthesis of the two halves of Anthramycin: 4 methyl-3-hydroxyanthranilic acid and a "dehydroproline acrylamide" moiety. These nonproteinogenic amino acid precursors are condensed by a two-module nonribosomal peptide synthetase (NRPS) terminated by a reductase domain, consistent with the final hemiaminal oxidation state of Anthramycin.
Vanessa V. Phelan - One of the best experts on this subject based on the ideXlab platform.
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Adenylation Enzyme Characterization Using γ -18O4-ATP Pyrophosphate Exchange
Chemistry & biology, 2009Co-Authors: Vanessa V. Phelan, John A. Mclean, Brian O. BachmannAbstract:We present here a rapid, highly sensitive nonradioactive assay for adenylation enzyme selectivity determination and characterization. This method measures the isotopic back exchange of unlabeled pyrophosphate into gamma-(18)O(4)-labeled ATP via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS), electrospray ionization liquid chromatography MS, or electrospray ionization liquid chromatography-tandem MS and is demonstrated for both nonribosomal (TycA, ValA) and ribosomal synthetases (TrpRS, LysRS) of known specificity. This low-volume (6 microl) method detects as little as 0.01% (600 fmol) exchange, comparable in sensitivity to previously reported radioactive assays and readily adaptable to kinetics measurements and high throughput analysis of a wide spectrum of synthetases. Finally, a previously uncharacterized A-T didomain from Anthramycin biosynthesis in the thermophile S. refuinius was demonstrated to selectively activate 4-methyl-3-hydroxyanthranilic acid at 47 degrees C, providing biochemical evidence for a new aromatic beta-amino acid activating adenylation domain and the first functional analysis of the Anthramycin biosynthetic gene cluster.
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Reassembly of Anthramycin Biosynthetic Gene Cluster by Using Recombinogenic Cassettes
Chembiochem : a European journal of chemical biology, 2008Co-Authors: Vanessa V. Phelan, Chris M. Farnet, Emmanuel Zazopoulos, Brian O. BachmannAbstract:The reassembly and heterologous expression of complete gene clusters in shuttle vectors has enabled investigations of several large biosynthetic pathways in recent years. With a gene cluster in a mobile construct, the interrogation of gene functions from both culturable and nonculturable organisms is greatly accelerated and large pathway engineering efforts can be executed to produce "new" natural products. However, the genetic manipulation of complete natural product biosynthetic gene clusters is often complicated by their sheer size (10-200 kbp), which makes standard restriction/ligation-based methods impracticable. To circumvent these problems, alternative recombinogenic methods, which depend on engineered homology-based recombination have recently arisen as a powerful alternative. Here, we describe a new general technique that can be used to reconstruct large biosynthetic pathways from overlapping cosmids by retrofitting each cosmid with a "recombinogenic cassette" that contains a shared homologous element and orthogonal antibiotic markers. We employed this technique to reconstruct the Anthramycin biosynthetic gene cluster of the thermotolerant actinomycete Streptomyces refuineus, from two >30 kbp cosmids into a single cosmid and integrate it into the genome of Streptomyces lividans. Anthramycin production in the heterologous Streptomyces host confirmed the integrity of the reconstructed pathway and validated the proposed boundaries of the gene cluster. Notably, Anthramycin production by recombinant S. lividans was seen only during growth at high temperature--a property also shown by the natural host. This work provides tools to engineer the Anthramycin biosynthetic pathway and to explore the connection between Anthramycin production and growth at elevated temperatures.
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Benzodiazepine Biosynthesis in Streptomyces refuineus
Chemistry & biology, 2007Co-Authors: Vanessa V. Phelan, Ioanna Ntai, Chris M. Farnet, Emmanuel Zazopoulos, Brian O. BachmannAbstract:Summary Anthramycin is a benzodiazepine alkaloid with potent antitumor and antibiotic activity produced by the thermophilic actinomycete Streptomyces refuineus sbsp. thermotolerans . In this study, the complete 32.5 kb gene cluster for the biosynthesis of Anthramycin was identified by using a genome-scanning approach, and cluster boundaries were estimated via comparative genomics. A λ-RED-mediated gene-replacement system was developed to provide supporting evidence for critical biosynthetic genes and to validate the boundaries of the proposed Anthramycin gene cluster. Sequence analysis reveals that the 25 open reading frame Anthramycin cluster contains genes consistent with the biosynthesis of the two halves of Anthramycin: 4 methyl-3-hydroxyanthranilic acid and a "dehydroproline acrylamide" moiety. These nonproteinogenic amino acid precursors are condensed by a two-module nonribosomal peptide synthetase (NRPS) terminated by a reductase domain, consistent with the final hemiaminal oxidation state of Anthramycin.
Florence Favre - One of the best experts on this subject based on the ideXlab platform.
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Studies towards the synthesis of antitumor antibiotics of the Anthramycin group
Tetrahedron Letters, 1991Co-Authors: Nicole Langlois, Florence FavreAbstract:Enamido-aldehyde 9, a new common synthon for the preparation of both sibiromycin and Anthramycin analogs has been synthetized from (S)-pyroglutamic acid
Khondaker M. Rahman - One of the best experts on this subject based on the ideXlab platform.
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Topical delivery of Anthramycin I. Influence of neat solvents
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2017Co-Authors: Tasnuva Haque, David E. Thurston, Khondaker M. Rahman, Jonathan Hadgraft, Majella E. LaneAbstract:Anthramycin (ANT) was the first pyrrolobenzodiazepine (PBD) molecule to be isolated, and is a potent cytotoxic agent. Although the PBD family has been investigated for use in systemic chemotherapy, their application in the management of actinic keratoses (AK) or skin cancer has not been investigated to date. In the present work, Anthramycin (ANT) was selected as a model PBD compound, and the skin penetration of the molecule was investigated using conventional Franz diffusion cells. Finite dose permeation studies of ANT were performed using propylene glycol (PG), 1,3-butanediol (BD), dipropylene glycol (DiPG), Transcutol P® (TC), propylene glycol monocaprylate (PGMC), propylene glycol monolaurate (PGML) and isopropyl myristate (IPM). The skin penetration of BD, DiPG, PG and TC was also measured. Penetration of ANT through human skin was evident for TC, PG and PGML with the active appearing to "track" the permeation of the vehicle in the case of TC and PG. Deposition of ANT in skin could be correlated with skin retention of the vehicle in the case of IPM, PGMC and PGML. These preliminary findings confirm the ability of ANT to penetrate human skin and, given the potency of the molecule, suggest that further investigation is justified. Additionally, the findings emphasise the critical importance of understanding the fate of the excipient for the rational design of topical formulations.
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entwicklung pyrrolobenzodiazepin pbd haltiger antikorper wirkstoff konjugate adcs ausgehend von Anthramycin
Angewandte Chemie, 2017Co-Authors: Julia Mantaj, Paul J. M. Jackson, Khondaker M. Rahman, David E. ThurstonAbstract:Die Pyrrolo[2,1-c][1,4]benzodiazepine (PBDs) sind eine Familie sequenzselektiver Wirkstoffe, die an die kleine Furche der DNA binden und eine kovalente Aminalbindung zwischen der C11-Position und den C2-NH2-Gruppen der Guaninbasen bilden. Anthramycin ist das erste Beispiel eines PBD-Monomers und wurde in den 1960er Jahren entdeckt. In den 1990er Jahren wurde das bekannteste PBD-Dimer SJG-136 entwickelt und hat jetzt bereits die klinischen Studien der Phase II in Patienten mit Leukamie und Eierstockkrebs durchlaufen. Seit kurzem werden aus PBD-Dimeranaloga und spezifisch an Tumorzellen bindenden Antikorpern Antikorper-Wirkstoff-Konjugate (ADCs) hergestellt. Von diesen befinden sich derzeit mehrere in klinischen Studien und viele andere in der praklinischen Entwicklung. Dieser Aufsatz zeigt die Entwicklung der PBDs ausgehend von Anthramycin uber die ersten PBD-Dimere bis hin zu PBD-haltigen ADCs und behandelt sowohl die Struktur-Wirkungs-Beziehungen und die Biologie der PBDs als auch die Strategien fur ihre Verwendung als Wirkstoffkomponente in ADCs.
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From Anthramycin to Pyrrolobenzodiazepine (PBD)-Containing Antibody-Drug Conjugates (ADCs).
Angewandte Chemie (International ed. in English), 2016Co-Authors: Julia Mantaj, Paul J. M. Jackson, Khondaker M. Rahman, David E. ThurstonAbstract:The pyrrolo[2,1-c][1,4]benzodiazepines (PBDs) are a family of sequence-selective DNA minor-groove binding agents that form a covalent aminal bond between their C11-position and the C2-NH2 groups of guanine bases. The first example of a PBD monomer, the natural product Anthramycin, was discovered in the 1960s, and the best known PBD dimer, SJG-136 (also known as SG2000, NSC 694501 or BN2629), was synthesized in the 1990s and has recently completed Phase II clinical trials in patients with leukaemia and ovarian cancer. More recently, PBD dimer analogues are being attached to tumor-targeting antibodies to create antibody-drug conjugates (ADCs), a number of which are now in clinical trials, with many others in pre-clinical development. This Review maps the development from Anthramycin to the first PBD dimers, and then to PBD-containing ADCs, and explores both structure-activity relationships (SARs) and the biology of PBDs, and the strategies for their use as payloads for ADCs.
-
Structures of PBDs used in this study.
2016Co-Authors: Julia Mantaj, Paul J. M. Jackson, Kersti Karu, Khondaker M. Rahman, David E. ThurstonAbstract:The naturally occurring Anthramycin as its C11-methyl ether (1), the synthetic PBD Dimer SJG-136 (2), and the synthetic C8-bis-pyrrole PBD Conjugate GWL-78 (3).
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Pyrrolobenzodiazepines (PBDs) Do Not Bind to DNA G-Quadruplexes - Figure 5
2014Co-Authors: Khondaker M. Rahman, Paul J. M. Jackson, David B. Corcoran, Tam T. T. Bui, David E. ThurstonAbstract:A & B, CD titration of Anthramycin (1) and the C8-PBD-morpholine (3), respectively, with the telomeric G-quadruplex sequence (HT4) demonstrating a lack of interaction; C & D, CD melting profile of Anthramycin:HT4 and C8-PBD-morpholine (3):HT4, respectively. For both molecules there was no change in CD melting temperature compared to the HT4 DNA alone.