Targeted chemotherapy by intratumour injection of encapsulated cells engineered to produce CYP2B1, an ifosfamide activating cytochrome P450

Löhr, Matthias; Müller, Petra; Karle, Peter; Stange, Jan; Mitzner, Steffen; Jesnowski, Ralf; Nizze, H; Nebe, Barbara; Liebe, Stefan; Salmons, Brian; Günzburg, W. H.

doi:10.1038/sj.gt.3300671

Cited by 97 publications

(96 citation statements)

References 26 publications

(33 reference statements)

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“…This approach has been shown to be effective for human pancreatic tumor cells xenotransplanted into nude mice. 10 Here we show that (a) PDs locally activated by encapsulated cells can exert a local cytotoxic effect and kill mammary tumor cells, (b) the approach can be extended from one SG/PD system, CYP2B1/IFO, to a second system, CD/5-FC, and (c) the combined antitumoral activity of CY2B1/IFO and CD/5-FC is superior to a single SG/PD approach.…”

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confidence: 76%

“…Both 4 hydroxy-IFO and 5-fluorouracil, are freely diffusible across cell membranes and thus can spread from gene-modified cells to adjacent nonmodified tumor cells. 9,10 The aim of any SG/PD approach is to enhance the antitumoral effect by local activation of the PD. This should allow high therapeutically relevant levels of the active toxic products to be generated at the site of the tumor, in the absence of similarly high systemic levels that are associated with unacceptable dose-limiting toxicity.…”

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confidence: 99%

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Combined chemotherapy of murine mammary tumors by local activation of the prodrugs ifosfamide and 5-fluorocytosine

et al. 2000

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The success of chemotherapeutic intervention is limited because the necessary high local drug doses cannot be achieved without systemic toxicity. Application of suicide genes (SGs) and direct conversion of prodrugs (PDs) to toxic metabolites in situ by SGs may enhance the efficacy of chemotherapy. To evaluate this strategy in two murine breast cancer models, TS/A and GR, we injected cellulose sulfate capsules harboring cat kidney cells expressing the SGs cytosine deaminase and cytochrome P450 2B1 (CYP2B1) intratumorally. The PDs 5-fluorocytosine and ifosfamide were administered in 3-day intervals. The effect of in situ chemotherapy with each PD alone and the combination was analyzed over a period of 100 days. The results reveal that for TS/A tumors, the antitumoral effect mediated by CYP2B1 is more efficient than that of cytosine deaminase, whereas for GR tumors, both systems worked equally well. Furthermore, we find additive toxicity using both SG/PD systems for both TS/A and GR tumors. Cancer Gene Therapy (2000) 7, 629 -636

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confidence: 76%

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confidence: 99%

Combined chemotherapy of murine mammary tumors by local activation of the prodrugs ifosfamide and 5-fluorocytosine

et al. 2000

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“…Other delivery methods reported include retroviral constructs, 26 oncolytic vectors 13,27 and direct implantation of encapsulated CYP-engineered cells. 28,29 However, the ability of adenoviral vectors to infect both dividing and nondividing cells increases the proportion of infected cells. Since adenoviral vectors do not integrate into the host chromosomes, there is no risk of integration and mutagenesis of infected host tissue.…”

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confidence: 99%

A virus-directed enzyme prodrug therapy (VDEPT) strategy for lung cancer using a CYP2B6/NADPH-cytochrome P450 reductase fusion protein

Tychopoulos

Corcos

Genne³

et al. 2005

Cancer Gene Ther

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Virus-directed enzyme prodrug therapy (VDEPT) is an emerging strategy against cancer. Our approach is a P450-based VDEPT that consists of using cyclophosphamide (CPA) as a prodrug and a Cytochrome P450 2B6/NADPH cytochrome P450 reductase fusion protein (CYP2B6/RED) as a prodrug-activating enzyme. Due to the heterogenous expression of proteins in tumor cells, basal reductase activity may not be sufficient to supply CYP2B6 with electrons, the fusion protein should enable the expression of both proteins at high levels in tumor cells. CYP/RED fusion proteins have never been previously expressed in mammalian cells, to enable expression the fusion protein was cloned into an adenoviral vector and subsequently several pulmonary tumor cell lines were infected. The CYP2B6/RED fusion protein was detected by Western blot, its mRNA by Northern blot, and its heme incorporation into an active form by spectral analysis. Infection with the fusion gene increased RED activity in microsomes by a factor of 3 compared to the control. After infection and treatment with CPA, in cell lines with low endogenous RED, the fusion protein mediated significantly higher CPA-induced cytotoxicity compared to cells expressing solely CYP2B6. In conclusion, the fusion protein is functional for VDEPT by providing one protein for higher levels of CPA metabolism. Cancer Gene Therapy (2005) Keywords: VDEPT; P450-based gene therapy; cyclophosphamide; lung cancer G ene-directed enzyme prodrug therapy (GDEPT) 1,2 is an emerging strategy used to improve the selectivity of cancer chemotherapy. This is accomplished through tumor-specific activation of noncytotoxic prodrugs to active drugs by drug-metabolizing enzymes. The general scheme consists of transfection of tumor cells with an enzyme responsible for the bioactivation of a noncytotoxic prodrug and treatment with the prodrug: only cells expressing the transfected drug-metabolizing enzyme can metabolize the prodrug into cytotoxic metabolites, leading to cell death. The use of viral vectors for transgene introduction is more specifically referred to as virusdirected enzyme prodrug therapy (VDEPT). Following promising early results of a P450-based GDEPT strategy, 3 using the rat 9L gliosarcoma cell line, cyclophosphamide (CPA) as a prodrug and CYP2B1 as the prodrug activating enzyme, our approach was to improve the strategy by activating CPA with cytochrome P450 2B6 (CYP2B6) 4,5 or a CYP2B6/NADPH cytochrome P450 reductase (RED) fusion protein in order to avoid the frequent problem of low RED expression in tumor cells. This constructed protein is the fusion of two human proteins namely CYP2B6 and the human RED resulting in a single protein able to transfer electrons from NADPH right through to the heme moiety of the protein to enable metabolism of CYP2B6 substrates. In order to achieve high levels of expression in mammalian cells, the proteins were cloned into adenoviral vectors by homologous recombination.CPA belongs to the oxazaphosphorine class of molecules 6,7 and remains a widely used cytotoxic agent f...

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“…The pioneering work involved the encapsulation of cells expressing cytochrome P450 enzymes for converting a benign prodrug (ifosfamide) into a toxic metabolite for the treatment of pancreatic cancer. [5][6][7][8] Such encapsulated cells implanted close to the tumor site provided an alternate source of cytochrome P450 activity (the liver being the primary source). This strategy was to overcome limitations such as high toxicity and systemic dilution experienced with the bolus injection of the prodrug.…”

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confidence: 99%

“…This strategy was to overcome limitations such as high toxicity and systemic dilution experienced with the bolus injection of the prodrug. 7,9 We have used a more direct approach for the treatment of cancer by delivering interleukin-2 (IL-2), to stimulate the immune rejection of tumor cells. 10 An IL-2 fusion protein targeted to the HER2/neu receptor on tumor cells was delivered from genetically modified encapsulated cells to treat murine solid tumors overexpressing the HER2/neu receptor.…”

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confidence: 99%

A multiprong approach to cancer gene therapy by coencapsulated cells

2005

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Targeted chemotherapy by intratumour injection of encapsulated cells engineered to produce CYP2B1, an ifosfamide activating cytochrome P450

Cited by 97 publications

References 26 publications

Combined chemotherapy of murine mammary tumors by local activation of the prodrugs ifosfamide and 5-fluorocytosine

Combined chemotherapy of murine mammary tumors by local activation of the prodrugs ifosfamide and 5-fluorocytosine

A virus-directed enzyme prodrug therapy (VDEPT) strategy for lung cancer using a CYP2B6/NADPH-cytochrome P450 reductase fusion protein

A multiprong approach to cancer gene therapy by coencapsulated cells

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