Purpose: A new universal tool for specific, non-covalent and non-destructive attachment of a recombinant antibody fragment to a polymer-modified adenovirus has been utilised to regulate the tropism of adenoviral gene delivery vector. Methods: We have prepared a multivalent reactive N-(2-hydroxypropyl)methacrylamide-based copolymer (PHPMA) bearing an α-bungarotoxin-binding peptide (BTXbp). The copolymer was used for covalent surface modification of adenoviral vectors (Ad). The α-bungarotoxin protein (BTX) has a nanomolar binding affinity for BTXbp, allowing non-covalent linkage of BTX fusion proteins. A single chain variable fragment of anti-PSMA antibody bearing BTX (scFv-BTX) binding to the prostate-specific membrane antigen (PSMA) was conjugated with the copolymer-coated adenovirus to enable specific infection of prostate cancer cells via PSMA receptors. Results: As shown by ELISA, the copolymer-coated virus exhibited much reduced binding to anti-Ad antibodies. Infection of PC-3 and LNCaP prostate cancer cells was ∼100-fold less efficient with copolymer-coated Ad than with un-modified Ad. Conjugation of scFv-BTX with Ad-PHPMA-BTXbp led to 5-10-fold restoration of infection in PSMA-positive LNCaP cells. In PSMA-negative PC-3 cells, the conjugation of scFv-BTX with Ad-PHPMA-BTXbp gave no enhancement of infection. Conclusions: We have shown that the presented Ad-PHPMA-BTXbp/scFv-BTX system can be used as a universal tool for a receptor-specific virotherapy.

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Keywords adenovirus, bungarotoxin, hydrophilic polymers, scFv, tumour targeting
Persistent URL dx.doi.org/10.1007/s11095-010-0088-8, hdl.handle.net/1765/21835
Willemsen, R.A, Pechar, M, Carlisle, R.C, Schooten, E, Pola, R, Thompson, A.J, … Ulbrich, K. (2010). Multi-component polymeric system for tumour cell-specific gene delivery using a universal bungarotoxin linker. Pharmaceutical Research, 27(11), 1–9. doi:10.1007/s11095-010-0088-8