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Tumor-selective drug activation: a GDEPT approach utilizing cytochrome P450 1A1 and AQ4N

Yakkundi, A, McErlane, V, Murray, M, McCarthy, HO, Ward, C, Hughes, Ciara, Patterson, LH, Hirst, DG, McKeown, Stephanie and Robson, T (2006) Tumor-selective drug activation: a GDEPT approach utilizing cytochrome P450 1A1 and AQ4N. CANCER GENE THERAPY, 13 (6). pp. 598-605. [Journal article]

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DOI: 10.1038/sj.cgt.7700933


Drug metabolizing transgene products, which activate bioreductive cytotoxins, can be used to target treatment-resistant hypoxic tumors. The prodrug AQ4N is bioreduced in hypoxic cells by cytochrome P450s (CYPs) to the cytotoxin AQ4. Previously we have shown that intra-tumoral injection of CYP3A4 and CYP2B6 transgenes with AQ4N and radiation inhibits tumor growth. Here we examine the ability of other CYPs, in particular CYP1A1, to metabolize AQ4N, and to enhance radiosensitization. Metabolism of AQ4N was assessed using microsomes prepared from baculovirus-infected cells transfected with various CYP isoforms. AQ4N metabolism was most efficient with CYP1A1 (66.7 nmol/min/pmol) and 2B6 (34.4 nmol/min/pmol). Transient transfection of human CYP1A1 +/- CYP reductase (CYPRED) was investigated in hypoxic RIF-1 mouse cells in vitro using the alkaline comet assay. There was a significant increase in DNA damage following transient transfection of CYP1A1 compared to non-transfected cells; inclusion of CYPRED provided no additional effect. In vivo, a single intra-tumoral injection of a CYP1A1 construct in combination with AQ4N (100 mg/kg i.p.) and 20 Gy X-rays caused a 16-day delay in tumor regrowth compared to tumors receiving AQ4N plus radiation and empty vector (P = 0.0344). The results show the efficacy of a CYP1A1-mediated GDEPT strategy for bioreduction of AQ4N.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Biomedical Sciences
Research Institutes and Groups:Institute of Nursing and Health Research > Centre for Health and Rehabilitation Technologies
Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Pharmacy & Pharmaceutical Sciences
ID Code:4309
Deposited By: Professor Stephanie McKeown
Deposited On:21 Dec 2009 12:19
Last Modified:01 Mar 2012 11:14

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