- Development and pre-clinical testing of a novel hypoxia-activated KDAC inhibitor
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Tumor hypoxia is associated with therapy resistance and poor patient prognosis. Hypoxia-activated prodrugs, designed to selectively target hypoxic cells while sparing normal tissue, represent a promising treatment strategy. We report the pre-clinical efficacy of 1-methyl-2-nitroimidazole panobinostat (NI-Pano, CH-03), a novel bioreductive version of the clinically used lysine deacetylase inhibitor, panobinostat. NI-Pano was stable in normoxic (21% O2) conditions and underwent NADPH-CYP-mediated enzymatic bioreduction to release panobinostat in hypoxia (2). Treatment of cells grown in both 2D and 3D with NI-Pano increased acetylation of histone H3 at lysine 9, induced apoptosis, and decreased clonogenic survival. Importantly, NI-Pano exhibited growth delay effects as a single agent in tumor xenografts. Pharmacokinetic analysis confirmed the presence of sub-micromolar concentrations of panobinostat in hypoxic mouse xenografts, but not in circulating plasma or kidneys. Together, our pre-clinical results provide a strong mechanistic rationale for the clinical development of NI-Pano for selective targeting of hypoxic tumors.
- Skwarska, Anna,Calder, Ewen D.D.,Sneddon, Deborah,Bolland, Hannah,Odyniec, Maria L.,Mistry, Ishna N.,Martin, Jennifer,Folkes, Lisa K.,Conway, Stuart J.,Hammond, Ester M.
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p. 1258 - 13,1270
(2021/09/16)
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- Hypoxia-activated pro-drugs of the KDAC inhibitor vorinostat (SAHA)
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Hypoxia (lower than normal oxygen) is a characteristic of most solid tumours that results in poor cancer patient prognosis. The difference in cellular environment between normoxia (21percent oxygen) or physoxia (4–7.5percent oxygen) and hypoxia (2.0percent oxygen) causes increased resistance to radio- and chemotherapy, but also provides the opportunity to selectively release hypoxia-activated pro-drugs. This approach potentially allows targeting of chemotherapies, including lysine deacetylase (KDAC) inhibitors, to the hypoxic fraction of cells. Here, we report initial work on the development of KDAC inhibitors that are selectively released in hypoxic conditions. We have shown that the addition of a 4-nitrobenzyl (NB) or 1-methyl-2-nitroimidazole (NI) bioreductive group onto the hydroxamic acid moiety of SAHA, giving NB-SAHA and NI-SAHA, abolishes KDAC inhibition activity. Both NB-SAHA and NI-SAHA undergo enzyme-mediated bioreduction, in a hypoxia-dependent manner, to release SAHA selectively in 0.1percent oxygen. This work provides an important foundation for further investigations into the targeted release of KDAC inhibitors in hypoxic tumours.
- Calder, Ewen D. D.,Conway, Stuart J.,Folkes, Lisa K.,Hammond, Ester M.,Mistry, Ishna N.,Skwarska, Anna,Sneddon, Deborah
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- Compositions and methods for treating cancer
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The invention provides a protected anti-neoplastic agent of the formula Hyp-N, wherein N is an anti-neoplastic agent and a protectable hydroxyl group of the anti-neoplastic is substituted with Hyp; Hyp is a moiety having the formula: wherein R 2 is hydrogen; R 3 is hydrogen or C 1 -C 6 alkyl; R 1 is C 1 -C 6 alkyl or C 1 -C 6 alkoxy, optionally substituted with one or more heteroatom-containing groups; and R 4 is hydrogen, C 1 -C 6 alkyl, or C 1 -C 6 alkoxy, optionally substituted with one or more heteroatom-containing groups.
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Paragraph 0189-0190
(2019/10/16)
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- Structure-activity relationship study of hypoxia-activated prodrugs for proteoglycan-targeted chemotherapy in chondrosarcoma
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Due to an abundant chondrogenic, poorly vascularized and particularly hypoxic extracellular matrix, chondrosarcoma, a malignant cartilaginous tumour, is chemo- and radio-resistant. Surgical resection with wide margins remains the mainstay of treatment. To address the lack of therapy, our strategy aims to increase anticancer drugs targeting and delivery in the tumour, by leveraging specific chondrosarcoma hallmarks: an extensive cartilaginous extracellular matrix, namely the high negative fixed charge density and severe chronic hypoxia. A dual targeted therapy for chondrosarcoma was investigated by conjugation of a hypoxia-activated prodrug (HAP) to quaternary ammonium (QA) functions which exhibit a high affinity for polyanionic sites of proteoglycans (PGs), the major components of the chondrosarcoma extracellular matrix. Based on preclinical results, an imidazole prodrug, ICF05016, was identified and provided the basis for a lead optimization study. A series of 27 QA-phosphoramide mustard conjugates, differing by the type of QA function and the length of the alkyl linker, was yielded by a common multi-step sequence involving phosphorylation of a key 2-nitroimidazole alcohol. Then, a screening was realized by surface plasmon resonance technology to assess biomolecular interactions between QA derivatives and aggrecan, the most abundant PG in chondrosarcoma. Results revealed that affinity depends more on the type of QA function, than on the linker length. Moreover, the presence of a benzyl group enhanced affinity to aggrecan. Twelve compounds were shortlisted and evaluated for antiproliferative activity (i.e., growth inhibiting concentration 50), under normoxic and hypoxic conditions using the human extraskeletal myeloid chondrosarcoma cell line (HEMC-SS). For all prodrugs, hypoxic selectivity was maintained and even increased, compared with the lead. From this study, compound 31f emerged as the most effective PG-targeted HAPs with a dissociation constant of 2.10 μM in the SPR experiment, a hypoxia cytotoxicity ratio of 24 and an efficient reductive cleavage under chemical and enzymatic conditions.
- Ghedira, Donia,Voissière, Aurélien,Peyrode, Caroline,Kraiem, Jamil,Gerard, Yvain,Maubert, Elise,Vivier, Magali,Miot-Noirault, Elisabeth,Chezal, Jean-Michel,Farhat, Farhat,Weber, Valérie
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- Bioreductively activatable prodrug conjugates of phenstatin designed to target tumor hypoxia
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A variety of solid tumor cancers contain significant regions of hypoxia, which provide unique challenges for targeting by potent anticancer agents. Bioreductively activatable prodrug conjugates (BAPCs) represent a promising strategy for therapeutic intervention. BAPCs are designed to be biologically inert until they come into contact with low oxygen tension, at which point reductase enzyme mediated cleavage releases the parent anticancer agent in a tumor-specific manner. Phenstatin is a potent inhibitor of tubulin polymerization, mimicking the chemical structure and biological activity of the natural product combretastatin A-4. Synthetic approaches have been established for nitrobenzyl, nitroimidazole, nitrofuranyl, and nitrothienyl prodrugs of phenstatin incorporating nor-methyl, mono-methyl, and gem-dimethyl variants of the attached nitro compounds. A series of BAPCs based on phenstatin have been prepared by chemical synthesis and evaluated against the tubulin-microtubule protein system. In a preliminary study using anaerobic conditions, the gem-dimethyl nitrothiophene and gem-dimethyl nitrofuran analogues were shown to undergo efficient enzymatic cleavage in the presence of NADPH cytochrome P450 oxidoreductase. Each of the eleven BAPCs evaluated in this study demonstrated significantly reduced inhibitory activity against tubulin in comparison to the parent anti-cancer agent phenstatin (IC50?=?1.0?μM). In fact, the majority of the BAPCs (seven of the eleven analogues) were not inhibitors of tubulin polymerization (IC50?>?20?μM), which represents an anticipated (and desirable) attribute for these prodrugs, since they are intended to be biologically inactive prior to enzyme-mediated cleavage to release phenstatin.
- Winn, Blake A.,Shi, Zhe,Carlson, Graham J.,Wang, Yifan,Nguyen, Benson L.,Kelly, Evan M.,Ross, R. David,Hamel, Ernest,Chaplin, David J.,Trawick, Mary L.,Pinney, Kevin G.
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p. 636 - 641
(2017/01/17)
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- PHOSPHORAMIDATE ALKYLATOR PRODRUGS
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Phosphoramidate alkylator prodrugs can be used to treat cancer when administered alone or in combination with one or more anti-neoplastic agents.
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Page/Page column 141-142
(2008/06/13)
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- 2-Nitroimidazol-5-ylmethyl as a potential bioreductively activated prodrug system: Reductively triggered release of the parp inhibitor 5- bromoisoquinolinone
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5-Chloromethyl-1-methyl-2-nitroimidazole reacted efficiently with the anion derived from 5-bromoisoquinolin-1-one to give 5-bromo-2-((1-methyl-2- nitroimidazol-5-yl)methyl)isoquinolin-1-one. Biomimetic reduction effected release of the 5-bromoisoquinolin-1-one. The 2-nitroimidazol-5-ylmethyl unit thus has potential for development as a general prodrug system for selective drug delivery to hypoxic tissues.
- Parveen, Ifat,Naughton, Declan P.,Whish, William J. D.,Threadgill, Michael D.
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p. 2031 - 2036
(2007/10/03)
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