Novel Prodrug-Like Fusion Toxin with Protease-Sensitive Bioorthogonal PEGylation for Tumor Targeting
Data(s) |
01/10/2014
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Resumo |
Highly potent biotoxins like Pseudomonas exotoxin A (ETA) are attractive payloads for tumor targeting. However, despite replacement of the natural cell-binding domain of ETA by tumor-selective antibodies or alternative binding proteins like designed ankyrin repeat proteins (DARPins) the therapeutic window of such fusion toxins is still limited by target-independent cellular uptake, resulting in toxicity in normal tissues. Furthermore, the strong immunogenicity of the bacterial toxin precludes repeated administration in most patients. Site-specific modification to convert ETA into a prodrug-like toxin which is reactivated specifically in the tumor, and at the same time has a longer circulation half-life and is less immunogenic, is therefore appealing. To engineer a prodrug-like fusion toxin consisting of the anti-EpCAM DARPin Ec1 and a domain I-deleted variant of ETA (ETA″), we used strain-promoted azide alkyne cycloaddition for bioorthogonal conjugation of linear or branched polyethylene glycol (PEG) polymers at defined positions within the toxin moiety. Reversibility of the shielding was provided by a designed peptide linker containing the cleavage site for the rhinovirus 3C model protease. We identified two distinct sites, one within the catalytic domain and one close to the C-terminal KDEL sequence of Ec1-ETA″, simultaneous PEGylation of which resulted in up to 1000-fold lower cytotoxicity in EpCAM-positive tumor cells. Importantly, the potency of the fusion toxin was fully restored by proteolytic unveiling. Upon systemic administration in mice, PEGylated Ec1-ETA″ was much better tolerated than Ec1-ETA″; it showed a longer circulation half-life and an almost 10-fold increased area under the curve (AUC). Our strategy of engineering prodrug-like fusion toxins by bioorthogonal veiling opens new possibilities for targeting tumors with more specificity and efficacy. |
Formato |
application/pdf |
Identificador |
http://boris.unibe.ch/61976/1/bc500468s.pdf Stefan, Nikolas; Zimmermann, Martina; Simon, Manuel; Zangemeister-Wittke, Uwe; Plückthun, Andreas (2014). Novel Prodrug-Like Fusion Toxin with Protease-Sensitive Bioorthogonal PEGylation for Tumor Targeting. Bioconjugate chemistry, 25(12), pp. 2144-2156. American Chemical Society 10.1021/bc500468s <http://dx.doi.org/10.1021/bc500468s> doi:10.7892/boris.61976 info:doi:10.1021/bc500468s info:pmid:25350699 urn:issn:1043-1802 |
Idioma(s) |
eng |
Publicador |
American Chemical Society |
Relação |
http://boris.unibe.ch/61976/ |
Direitos |
info:eu-repo/semantics/restrictedAccess |
Fonte |
Stefan, Nikolas; Zimmermann, Martina; Simon, Manuel; Zangemeister-Wittke, Uwe; Plückthun, Andreas (2014). Novel Prodrug-Like Fusion Toxin with Protease-Sensitive Bioorthogonal PEGylation for Tumor Targeting. Bioconjugate chemistry, 25(12), pp. 2144-2156. American Chemical Society 10.1021/bc500468s <http://dx.doi.org/10.1021/bc500468s> |
Palavras-Chave | #610 Medicine & health |
Tipo |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion PeerReviewed |