Heap J.T.,University of Nottingham |
Heap J.T.,Imperial College London |
Theys J.,Maastricht University |
Ehsaan M.,University of Nottingham |
And 8 more authors.
Oncotarget | Year: 2014
Spores of some species of the strictly anaerobic bacteria Clostridium naturally target and partially lyse the hypoxic cores of tumors, which tend to be refractory to conventional therapies. The anti-tumor effect can be augmented by engineering strains to convert a non-toxic prodrug into a cytotoxic drug specifically at the tumor site by expressing a prodrug-converting enzyme (PCE). Safe doses of the favored prodrug CB1954 lead to peak concentrations of 6.3 μM in patient sera, but at these concentration(s) known nitroreductase (NTR) PCEs for this prodrug show low activity. Furthermore, efficacious and safe Clostridium strains that stably express a PCE have not been reported. Here we identify a novel nitroreductase from Neisseria meningitidis, NmeNTR, which is able to activate CB1954 at clinically-achievable serum concentrations. An NmeNTR expression cassette, which does not contain an antibiotic resistance marker, was stably localized to the chromosome of Clostridium sporogenes using a new integration method, and the strain was disabled for safety and containment by making it a uracil auxotroph. The efficacy of Clostridium-Directed Enzyme Prodrug Therapy (CDEPT) using this system was demonstrated in a mouse xenograft model of human colon carcinoma. Substantial tumor suppression was achieved, and several animals were cured. These encouraging data suggest that the novel enzyme and strain engineering approach represent a promising platform for the clinical development of CDEPT.
Jaberipour M.,University of Birmingham |
Vass S.O.,University of Birmingham |
Guise C.P.,University of Birmingham |
Grove J.I.,University of Birmingham |
And 4 more authors.
Biochemical Pharmacology | Year: 2010
Prodrug activation gene therapy for cancer involves expressing prodrug-activating enzymes in tumour cells, so they can be selectively killed by systemically administered prodrug. For example, Escherichia coli nfsB nitroreductase (E.C. 18.104.22.168)(NTR), sensitises cells to the prodrug CB1954 (5-[aziridin-1-yl]-2,4-dinitrobenzamide), which it converts to a potent DNA-crosslinking agent. However, low catalytic efficiency with this non-natural substrate appears to limit the efficacy of this enzyme prodrug combination for eliminating the target cancer cells. To improve this, we aim to engineer NTR for improved prodrug activation. Previously, a number of single amino acid substitutions at six positions around the active site of the enzyme were found to increase activity, resulting in up to ∼5-fold enhanced cell sensitisation to CB1954. In this study we have made pairwise combinations among some of the best mutants at each of these 6 sites. A total of 53 double mutants were initially screened in E. coli, then the 7 most promising were inserted into an adenovirus vector and compared in SKOV3 human ovarian carcinoma cells for sensitisation to CB1954 and two alternative prodrugs. The most effective mutants, T41L/N71S and T41L/F70A, were 14-17-fold more potent than WT NTR at sensitising the cancer cells to CB1954. The best mutant for activation of the dinitrobenzamide mustard prodrug SN23862 was T41L/F70A (4.8-fold improvement); and S40A/F124M showed 1.7-fold improvement over WT with the nitrobenzylphosphoramide mustard prodrug LH7. In two tumour xenograft models using SKOV3 or human prostate carcinoma PC3, T41L/N71S NTR demonstrated greater CB1954-dependent anti-tumour activity than WT NTR. © 2009 Elsevier Inc.
Rattray N.J.W.,University of Manchester |
Zalloum W.A.,University of Manchester |
Mansell D.,University of Manchester |
Latimer J.,University of Manchester |
And 3 more authors.
Tetrahedron | Year: 2013
Sterically constrained probes 2,4-O-bisdansyl-6,7-diazabicyclo[3.2.1]oct-6- ene (8) and 2,4-O-bispyrenoyl-6,7-diazabicyclo[3.2.1]oct-6-ene (9) exhibit specific dimer fluorescent characteristics (λmax 555 nm and 511 nm, respectively), attributed to the 2,4-diaxial arrangement of the dansyl or pyrene groups. Reduction of the azo-conformational locking group in (8) and (9) yielded 1,3-bisdansyl-4,6-diaminocyclohexane (16) and 1,3-bispyrenoyl-4,6- diaminocyclohexane (17) in the tetra-equatorial chair conformation, thus minimising interaction of the bisdansyl or bispyrenoyl groups. This induces a change in fluorescence from a cooperative green emission dimer band to a blue-shifted, monomer type fluorescence, with λmax 448 nm and 396 nm for the reduced forms (16) and (17), respectively. The azo-bond conformational lock can either be reduced under biomimetic conditions (using sodium dithionite) or with bacteria (Clostridium perfringens or Escherichia coli) utilising azo-reductase enzymes. These fluorescent probes have the potential to specifically detect azo-reductase expressing bacteria.
Huang W.,University of Liverpool |
Huang W.,University of Sichuan |
Booth D.M.,University of Liverpool |
Cane M.C.,University of Liverpool |
And 15 more authors.
Gut | Year: 2014
Objective Non-oxidative metabolism of ethanol (NOME) produces fatty acid ethyl esters (FAEEs) via carboxylester lipase (CEL) and other enzyme action implicated in mitochondrial injury and acute pancreatitis (AP). This study investigated the relative importance of oxidative and nonoxidative pathways in mitochondrial dysfunction, pancreatic damage and development of alcoholic AP, and whether deleterious effects of NOME are preventable. Design Intracellular calcium ([Ca2+]C), NAD(P)H, mitochondrial membrane potential and activation of apoptotic and necrotic cell death pathways were examined in isolated pancreatic acinar cells in response to ethanol and/or palmitoleic acid (POA) in the presence or absence of 4-methylpyrazole (4-MP) to inhibit oxidative metabolism. A novel in vivo model of alcoholic AP induced by intraperitoneal administration of ethanol and POA was developed to assess the effects of manipulating alcohol metabolism. Results Inhibition of OME with 4-MP converted predominantly transient [Ca2+]C rises induced by low ethanol/POA combination to sustained elevations, with concurrent mitochondrial depolarisation, fall of NAD(P)H and cellular necrosis in vitro. All effects were prevented by 3-benzyl-6-chloro-2-pyrone (3-BCP), a CEL inhibitor. 3-BCP also significantly inhibited rises of pancreatic FAEE in vivo and ameliorated acute pancreatic damage and inflammation induced by administration of ethanol and POA to mice. Conclusions A combination of low ethanol and fatty acid that did not exert deleterious effects per se became toxic when oxidative metabolism was inhibited. The in vitro and in vivo damage was markedly inhibited by blockade of CEL, indicating the potential for development of specific therapy for treatment of alcoholic AP via inhibition of FAEE generation.
Morvus Technology | Date: 2014-06-13
Use of an orally or nasally available formulation of Tretazicar for poisoning vermin. An orally available or nasally available formulation of Tretazicar, wherein in the orally available formulation the Tretazicar is protected from acid hydrolysis, and provided that the formulation is not solid Tretazicar in a gelatin capsule. A formulation of Tretazicar in which the Tretazicar is protected from acid hydrolysis, wherein the formulation is present in a liquid form. A combination of Tretazicar and bait. A method of poisoning vermin comprising making available to the vermin an orally or nasally available formulation of Tretazicar and allowing the vermin to ingest or inhale the formulation of Tretazicar.
Morvus Technology | Date: 2015-02-23
There is provided the use as reducing agents of alpha-hydroxycarbonyl compounds capable of forming cyclic dimers. There is also provided corresponding methods of reducing reducible compounds, particularly reduction-activated prodrugs. Examples of the alpha-hydroxycarbonyl compounds used are dihydroxyacetone, glycolaldehyde, glyceraldehyde, erythrose, xylulose, erythrulose or 3-hydroxy-2-butanone.
Morvus Technology | Date: 2015-12-04
The present application discloses a DNA molecule comprising a modified Group II intron which does not express the intron-encoded reverse transcriptase but which contains a modified selectable marker gene in the reverse orientation, wherein the marker gene comprises a Group I intron in forward orientation of causing expression in a bacteria cell of the class Clostridia and wherein the DNA molecule comprises sequences that allow for the insertion of the RNA transcript of the Group II intron in the chromosome of a bacterial cell of the class Clostridia. A method of introducing a nucleic acid molecule into a site of a DNA molecule in a bacterial cell of the class Clostridia is also provided. The DNA molecule and the method are useful for making mutations Clostridium spp.
Morvus Technology | Date: 2010-12-08
There is provided 5-(aziridin-1-yl)-4-hydroxylamino-2-nitrobenzamide for various uses, as well as pharmaceutical compositions and devices comprising 5-(aziridin-1-yl)-4-hydroxylamino-2-nitrobenzamide. There is also provided a method for reducing reducible compounds (such as reduction-activated prodrugs, e.g. tretazicar) by contacting those compounds with -hydroxycarbonyl compounds capable of forming cyclic dimers.
PubMed | Morvus Technology and Northumbria University
Type: Journal Article | Journal: Bioorganic & medicinal chemistry letters | Year: 2016
A series of N-nitroarylated-3-chloromethyl-1,2,3,4-tetrahydroisoquinoline derivatives, several of which also possessed a trifluoromethyl substituent, were prepared and assessed as potential nitroaromatic prodrugs. The enzymatic reduction of these compounds and their cytotoxicities were studied. The compounds were cytotoxic, but this is probably not related to their enzymatic reduction.