PCI-enhanced adenoviral transduction employs the known uptake mechanism of adenoviral particles

Abstract

The development of methods for efficient and specific delivery of therapeutic genes into target tissues is an important issue for further development of in vivo gene therapy. In the present study, the physical targeting technique, photochemical internalization (PCI), has been used together with adenovirus. The combination of PCI and adenoviral transduction has previously been shown to be favorable compared to adenovirus used alone, and the aim of this study was to verify the role of the adenoviral receptors and identify the uptake pathway used by adenoviral particles in photochemically treated cells. All examined cell lines showed augmented transduction efficiency after PCI-treatment, with a maximum of 13-fold increase in transgene expression compared to conventionally infected cells. Blocking of CAR induced a complete inhibition of PCI-enhanced transgene expression. However, photochemical treatment managed to enhance the transduction efficiency of the retargeted virus AdRGD-GFP showing also that the virus-CAR interaction is not vital for obtaining a photochemical effect on adenoviral transduction. Blocking the a V -integrins reduced the gene expression significantly in photochemically treated cells. Subjecting HeLa cells expressing negative mutant-dynamin to light treatment after infection gave no significant increase in gene transfer, while the gene transfer were enhanced seven-fold in cells with wild-type dynamin. Furthermore, chlorpromazine inhibited photochemical transduction in a dose-dependent manner, whereas Filipin III had no effect on the gene transfer. In summary, the data presented imply that adenoviral receptor binding is important and clathrin-mediated endocytosis is the predominant uptake mechanism for adenoviral particles in photochemically treated cells.

Photochemical treatment with endosomally localized photosensitizers enhances the number of adenoviruses in the nucleus

“…The selectivity of the treatment is further enhanced by the tumor preferential localization of the photosensitizers [36], and could additionally be improved by combining PCI with transcriptional and transductional targeted adenovirus. PCI has already been combined successfully with RGD- [21] and EGFR-targeted [37] adenoviruses.…”

Cytosolic Delivery of Liposomally Targeted Proteins Induced by Photochemical Internalization

“…Selbo et al demonstrated that the use of PCI enhanced the potency of the plant toxin gelonin in inhibiting cellular protein synthesis by a factor of 300 (21). In addition, the low-molecular weight drug bleomycin (22), antigenic peptides (23), immunotoxins (24,25), peptide nucleic acids (26) and even colloidal carriers for gene delivery (27)(28)(29) have been successfully delivered into the cytosol via PCI. These agents generally are not able to reach their intracellular target site efficiently, due to lack of capability to pass cellular membranes and/or the occurrence of degradation within endocytic vesicles.…”

Photochemically stimulated drug delivery increases the cytotoxicity and specificity of EGF–saporin

“…PCI has been shown to increase the cytosolic delivery and subsequent therapeutic effect in vitro of many macromolecules such as proteins (Selbo et al 2000a, Dietze et al 2003, immunotoxins (Selbo et al 2000b, Selbo et al 2001a and DNA delivered by cationic polymers , Prasmickaite et al 2001, adenovirus , Engesaeter et al 2005, Engesaeter et al 2006a, Engesaeter et al 2006b) and adenoassociated virus . PCI in vitro has also been reported as an intracellular delivery system for peptides (Berg et al 1996, Berg et al 1999, PNAs (Shiraishi & Nielsen 2006, siRNA (Oliveira et al 2007) and some chemotherapeutics, such as bleomycin , doxorubicin , Lai et al 2007) and mitoxantrone (Adigbli et al 2007).…”