A Phase I/II Clinical Trial in Localized Prostate Cancer of an Adenovirus Expressing Nitroreductase with CB1984

Patel, Prashant; Young, J. G.; Mautner, Vivien; Ashdown, Daniel; Bonney, Sarah; Pineda, Robert G.; Collins, Stuart; Searle, Peter F.; Hull, Diana; Peers, Elizabeth; Chester, John D.; Wallace, David; Doherty, Alan; Leung, Hing Y.; Young, Lawrence S.; James, Nicholas D.

doi:10.1038/mt.2009.80

Cited by 116 publications

(109 citation statements)

References 27 publications

Supporting

Mentioning

106

Contrasting

Order By: Relevance

“…19,22 NTR/CB1954 is another GDEPT strategy with therapeutic potential that is currently in clinical trials. 8 The NTR enzyme is responsible for reduction of nontoxic prodrug CB1954 to its activated cytotoxic form (5-(aziridin-1-yl)-4-hydroxylamino-2-nitrobenzamide: a DNA inter-strand cross-linking agent) that kills cancer cells expressing the enzyme. In contrast to the HSV1-tk/GCV strategy, NTR/CB1954 is expected to demonstrate superior therapeutic efficacy, as it kills both dividing and growth-arrested cancer cells, exhibits potent bystander effect and lacks resistance to common chemotherapeutic agents such as cisplatin.…”

Section: Discussionmentioning

confidence: 99%

“…24 More recently, a replication-defective adenoviral vector CTL102 encoding gene has been used on patients with primary or secondary liver cancer 25 and prostate cancer. 8,26 However, there are many challenges yet to be overcome for it to be considered a robust therapy. For any GDEPT system, there is a need for methods to monitor sufficient incorporation of the transgenes into tumor cells, gauge adequate level of gene expression and predict the duration of transgene expression in cancer Noninvasive optical imaging of NTR GDEPT system S Bhaumik et al cells.…”

Section: Discussionmentioning

confidence: 99%

“…3,4 Currently, the three most promising suicide gene/prodrug combinations are (1) herpes simplex virus thymidine kinase (HSV1-tk) with ganciclovir (GCV), 5 (2) CD (cytosine deaminase) from bacteria or yeast with 5-fluorocytidine 6,7 and (3) bacterial nitroreductase (NTR) with CB1954. 8 Of the three, HSV1-tk/GCV is at the forefront of gene therapy. 9,10 The advancement and success of HSV1-tk gene therapy in clinics is due to its dual capability to act as a therapeutic gene as well as a reporter gene that can be imaged by appropriate radioactive probe under PET/SPECT (positron emission tomography/single photon emission computed tomography) scanners.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Noninvasive optical imaging of nitroreductase gene-directed enzyme prodrug therapy system in living animals

et al. 2011

View full text Add to dashboard Cite

Gene-directed enzyme prodrug therapy (GDEPT) is a promising and emerging strategy that attempts to limit the systemic toxicity inherent to cancer chemotherapy by means of tumor-targeted delivery and expression of an exogenous gene whose product converts nontoxic prodrug(s) into activated cytotoxic agent(s). The bacterial nitroreductase (NTR) enzyme, coupled with its substrate prodrug 5-(azaridin-1-yl)-2,4-dinitrobenzamide (CB1954), is a promising GDEPT strategy that has reached clinical trials. However, no strategy exists to visually monitor and quantitatively evaluate the therapeutic efficacy of NTR/CB1954 prodrug therapy in cells and imaging in living animals. As the success of any GDEPT is dependent upon the efficiency of transgene expression in vivo, we developed a safe, sensitive and reproducible noninvasive imaging method to monitor NTR transgene expression that would allow quantitative assessment of both therapeutic efficacy and diagnostic outcome of NTR/ CB1954 prodrug therapy in the future. Here, we investigate the use of a novel fluorescent imaging dye CytoCy5S (a Cy5-labeled quenched substrate of NTR enzyme) on various cancer cell lines in vitro and in NTR-transfected tumor-bearing animals in vivo. CytoCy5S-labeled cells become fluorescent at 'red-shifted' wavelengths (638 nm) when reduced by cellular NTR enzyme and remains trapped within the cells for extended periods of time. The conversion and entrapment was dynamically recorded using a time-lapsed microscopy. Systemic and intratumoral delivery of CytoCy5S to NTR-expressing tumors in animals indicated steady and reproducible signals even 16 h after delivery (Po0.001). This is the first study to address visual monitoring and quantitative evaluation of NTR activity in small animals using CytoCy5S, and establishes the capability of NTR to function as an imageable reporter gene.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Noninvasive optical imaging of nitroreductase gene-directed enzyme prodrug therapy system in living animals

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Therapeutic combinations such as the herpes simplex virus thymidine kinase (HSVtk) gene and its prodrug ganciclovir (GCV), or bacterial nitroreductase (NTR) and its prodrug CB1954, produce toxic metabolites that are freely diffusible and able to kill neighboring cells via a 'bystander effect'. 13,14 Both systems are well characterized and have been investigated in clinical trials, [15][16][17] but have not been compared in parallel under hypoxic conditions under the control of different transcriptional promoters. The combination of transcriptional regulation, hypoxia-selective HREs and adenoviral delivery of prodrug-activating genes therefore provides great potential for selective targeting of hypoxic regions within solid tumors.…”

Section: Introductionmentioning

confidence: 99%

Adenovirus-mediated hypoxia-targeted gene therapy using HSV thymidine kinase and bacterial nitroreductase prodrug-activating genes in vitro and in vivo

et al. 2011

View full text Add to dashboard Cite

Hypoxia is an important factor in tumor growth. It is associated with resistance to conventional anticancer treatments. Gene therapy targeting hypoxic tumor cells therefore has the potential to enhance the efficacy of treatment of solid tumors. Transfection of a panel of tumor cell lines with plasmid constructs containing hypoxia-responsive promoter elements from the genes, vascular endothelial growth factor (VEGF) and erythropoietin, linked to the minimal cytomegalovirus (mCMV) or minimal interleukin-2 (mIL-2) promoters showed optimum hypoxia-inducible luciferase reporter gene expression with five repeats of VEGF hypoxic-response element linked to the mCMV promoter. Adenoviral vectors using this hypoxia-inducible promoter to drive therapeutic transgenes produced hypoxia-specific cell kill of HT1080 and HCT116 cells in the presence of prodrug with both herpes simplex virus thymidine kinase/ganciclovir and nitroreductase (NTR)/CB1954 prodrug-activating systems. Significant cytotoxic effects were also observed in patient-derived human ovarian cancer cells. The NTR/CB1954 system provided more readily controllable transgene expression and so was used for in vivo experiments of human HCT116 xenografts in nude mice. Subjects treated intratumorally with Ad-VEGFmCMV-NTR and intraperitoneal injection of CB1954 demonstrated a statistically significant reduction in tumor growth. Immunohistochemistry of treated xenografts showed a good correlation between transgene expression and hypoxic areas. Further investigation of these hypoxia-inducible adenoviral vectors, alone or in combination with existing modalities of cancer therapy, may aid in the future development of successful Gene-Directed Enzyme Prodrug Therapy systems, which are much needed for targeting solid tumors.

show abstract

“…A c c e p t e d M a n u s c r i p t 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Page 4 PSA (prostate specific antigen) in some patients [28], but greater efficacy is required.…”

Section: Page 4 Of 43mentioning

confidence: 99%

Testing double mutants of the enzyme nitroreductase for enhanced cell sensitisation to prodrugs: Effects of combining beneficial single mutations

Jaberipour

Vass

Guise

et al. 2010

Biochemical Pharmacology

View full text Add to dashboard Cite

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A c c e p t e d M a n u s c r i p t 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Page 2 AbstractProdrug 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, E. coli nfsB nitroreductase (E.C. 1.6.99.7)(NTR), sensitises cells to the prodrug CB1954 (5-[aziridin-1-yl]-2,4-dinitrobenzamide), which it converts to a potent DNAcrosslinking 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 6 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 SKOV3human 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.

show abstract

A Phase I/II Clinical Trial in Localized Prostate Cancer of an Adenovirus Expressing Nitroreductase with CB1984

Cited by 116 publications

References 27 publications

Noninvasive optical imaging of nitroreductase gene-directed enzyme prodrug therapy system in living animals

Noninvasive optical imaging of nitroreductase gene-directed enzyme prodrug therapy system in living animals

Adenovirus-mediated hypoxia-targeted gene therapy using HSV thymidine kinase and bacterial nitroreductase prodrug-activating genes in vitro and in vivo

Testing double mutants of the enzyme nitroreductase for enhanced cell sensitisation to prodrugs: Effects of combining beneficial single mutations

Contact Info

Product

Resources

About