Pseudomonas exotoxin A: From virulence factor to anti-cancer agent

Wolf, Philipp; Elsässer‐Beile, Ursula

doi:10.1016/j.ijmm.2008.08.003

Cited by 149 publications

(132 citation statements)

References 111 publications

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“…As shown in Supplementary Fig. S5C, on HT29 cells PEG 20kDa -3C-Ec1-ETA 00 showed a 10-fold lower potency (calculated as IC 50 ), compared with Ec1-ETA 00 , but completely regained its activity upon removal of the polymer.…”

Section: Cytotoxicity Of Fusion Toxinsmentioning

confidence: 89%

“…Cellular intoxication by ETA 00 is a complex process (27,50,51), several steps of which might be negatively affected by a bulky polymer. On the basis of this consideration, PEGylation may improve tumor localization of the fusion toxin and reduce its uptake by the reticuloendothelial system (RES), but once it encounters its target cell becomes dispensable or even unwanted.…”

Section: Discussionmentioning

confidence: 99%

“…Serial dilutions of the fusion toxins were used to determine the IC 50 (concentration at which cell viability was decreased by 50%) of the constructs in XTT (2,3-bis[2-methoxy-4-nitro-S-sulfophenynl]H-tetrazolium-5-carboxanilide inner salt) assays (the Cell Proliferation Kit II; Roche Diagnostics GmbH). Briefly, 5,000 cells were seeded into a 96-well plate, incubated overnight in a standard humidified cell culture incubator (37 C, 5% CO 2 ), and treated with the fusion toxins in quadruplicates the following day.…”

Section: Cytotoxicity Assaymentioning

confidence: 99%

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Increasing the Antitumor Effect of an EpCAM-Targeting Fusion Toxin by Facile Click PEGylation

Simon

Stefan

Borsig

et al. 2014

Molecular Cancer Therapeutics

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Fusion toxins used for cancer-related therapy have demonstrated short circulation half-lives, which impairs tumor localization and, hence, efficacy. Here, we demonstrate that the pharmacokinetics of a fusion toxin composed of a designed ankyrin repeat protein (DARPin) and domain I-truncated Pseudomonas Exotoxin A (PE40/ETA 00 ) can be significantly improved by facile bioorthogonal conjugation with a polyethylene glycol (PEG) polymer at a unique position. Fusion of the anti-EpCAM DARPin Ec1 to ETA 00 and expression in methionine-auxotrophic E. coli enabled introduction of the nonnatural amino acid azidohomoalanine (Aha) at position 1 for strain-promoted click PEGylation. PEGylated Ec1-ETA 00 was characterized by detailed biochemical analysis, and its potential for tumor targeting was assessed using carcinoma cell lines of various histotypes in vitro, and subcutaneous and orthotopic tumor xenografts in vivo. The mild click reaction resulted in a welldefined mono-PEGylated product, which could be readily purified to homogeneity. Despite an increased hydrodynamic radius resulting from the polymer, the fusion toxin demonstrated high EpCAM-binding activity and retained cytotoxicity in the femtomolar range. Pharmacologic analysis in mice unveiled an almost 6-fold increase in the elimination half-life (14 vs. 82 minutes) and a more than 7-fold increase in the area under the curve (AUC) compared with non-PEGylated Ec1-ETA 00 , which directly translated in increased and longer-lasting effects on established tumor xenografts. Our data underline the great potential of combining the inherent advantages of the DARPin format with bioorthogonal click chemistry to overcome the limitations of engineering fusion toxins with enhanced efficacy for cancer-related therapy. Mol Cancer Ther; 13(2); 375-85. Ó2013 AACR.

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Section: Cytotoxicity Of Fusion Toxinsmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Cytotoxicity Assaymentioning

confidence: 99%

See 1 more Smart Citation

Increasing the Antitumor Effect of an EpCAM-Targeting Fusion Toxin by Facile Click PEGylation

Simon

Stefan

Borsig

et al. 2014

Molecular Cancer Therapeutics

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“…5,6 Pseudomonas exotoxin (PE) is often used as a toxic moiety because it is highly toxic to eukaryotic cells. Monoclonal antibodies as well as cytokines and…”

mentioning

confidence: 99%

“…5,6 Pseudomonas exotoxin (PE) is often used as a toxic moiety because it is highly toxic to eukaryotic cells. Monoclonal antibodies as well as cytokines and chemokines are used as targeting moieties in the construction of recombinant immunotoxins because of their specificity and high binding affinity to the target cells.…”

mentioning

confidence: 99%

Investigation of a plasmid containing a novel immunotoxin VEGF165‐PE38 gene for antiangiogenic therapy in a malignant glioma model

Chen

et al. 2010

Intl Journal of Cancer

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Inhibition of tumor neovascularization has profound effects on the growth of solid tumors. Our previous studies have shown the effect of VEGF165-PE38 recombinant immunotoxin on proliferation and apoptosis in human umbilical vein endothelial cells in vitro. In this study, we explored the direct inhibition of angiogenesis in chick chorioallantoic membrane and antiangiogenic therapy in a malignant glioma model. HEK293 cells were transfected with the pVEGF165PE38-IRES2-EGFP plasmid. ELISA was used to confirm the expression of VEGF165-PE38 in the transfected cells. These cells released 1396 6 131.9 pg VEGF165-PE38/1310 4 cells/48 h into the culture medium and the supernatant was capable of inhibiting the growth of capillary-like structures in chick chorioallantoic membrane assay. In a murine malignant glioma model, plasmid was directly administered via multiple local intratumoral delivery. After day 16 the tumor volume in mice treated with pVEGF165PE38-IRES2-EGFP was significantly lower than that in mice in the control groups. Immunohistochemistry studies showed that the treated group had decreased expression of CD31. ). Immunohistochemistry analysis indicated that immunotoxin VEGF165-PE38 was distributed in the treated group in malignant glioma tissue. Our findings provide evidence that the in vivo production of VEGF165-PE38 through gene therapy using a eukaryotic expression plasmid had potential antiangiogenic activity in malignant glioma in vivo.A promising approach to cancer therapy is based on an attack on new blood vessels rather than a direct attack on cancer cells. This approach may, thus, multiply the effects of anticancer drugs. 1 In addition, such a stromal therapy approach carries the prospect of being less prone to resistance mechanisms theoretically due to genetic stability.2 Several reports have indicated that therapies aimed at tumor vasculature such as angiostatin, endostatin, humanized monoclonal antibody directed against vascular endothelial growth factor (VEGF; bevacizumab) and other small molecule receptor tyrosine kinase inhibitors (sorafenib and sunitinib) 3 can lead to rapid regression of existing tumors. However, these inhibitors of angiogenesis do not destroy tumor vasculature, which can regenerate when these drugs are discontinued.4 These concerns raise the following questions with respect to improving antiangiogenic therapy: is it possible to find a therapeutic strategy aimed at destroying tumor vasculature endothelial cells but not inhibiting normal vasculature endothelial cell growth? Is it possible to completely destroy the tumor vasculature network system?Immunotoxin is a hybrid molecule that consists of a targeting moiety and a toxic moiety. 5,6 Pseudomonas exotoxin (PE) is often used as a toxic moiety because it is highly toxic to eukaryotic cells. Monoclonal antibodies as well as cytokines and

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PseudomonasExotoxin A‐Based Immunotoxins for Targeted Cancer Therapy

Wolf

Elsässer‐Beile

2010

Emerging Cancer Therapy

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Pseudomonas exotoxin A: From virulence factor to anti-cancer agent

Cited by 149 publications

References 111 publications

Increasing the Antitumor Effect of an EpCAM-Targeting Fusion Toxin by Facile Click PEGylation

Increasing the Antitumor Effect of an EpCAM-Targeting Fusion Toxin by Facile Click PEGylation

Investigation of a plasmid containing a novel immunotoxin VEGF165‐PE38 gene for antiangiogenic therapy in a malignant glioma model

PseudomonasExotoxin A‐Based Immunotoxins for Targeted Cancer Therapy

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