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

Abstract

BACKGROUND:

In the present study the physical targeting technique photochemical internalization (PCI) has been used in combination with adenovirus. We have previously shown that PCI enhances transgene expression from AdhCMV-lacZ, and the aim of the present study was to further increase the understanding of photochemically mediated adenoviral transduction.

METHODS:

Two colorectal carcinoma cell lines, WiDr and HCT116, were pre-incubated with the photosensitizer TPPS(2a) or methylene blue derivates (MBD) followed by infection with adenovirus and light exposure. Transgene expression was measured by flow cytometry. Real-time polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH) were used to quantify the level of viral DNA in the nuclei. Real-time PCR was also used to measure the level of beta-galactosidase mRNA in samples infected with AdhCMV-lacZ.

RESULTS:

Exposing TPPS(2a)-treated cells to light enhanced the quantity of viral DNA in the nucleus, the mRNA level of the transgene and the transgene expression compared to non-illuminated cells. The increased transgene expression was independent of the promoter used, but dependent on the time of light exposure and the cellular localization of the photosensitizer.

CONCLUSIONS:

The enhanced transgene expression observed after photochemical treatment is most likely not a result of one event, but more an interplay between various mechanisms. An increased level of adenoviral DNA in the nucleus and a dependency of endosomal localization of the photosensitizer to obtain enhanced transgene expression suggested that endosomal rupture facilitated the transport of adenoviruses to the nucleus.

• Authors: Birgit Ø Engesaeter, Siri Tveito, Anette Bonsted, Olav Engebraaten, Kristian Berg, Gunhild M Maelandsmo
• Journal: The journal of gene medicine (J Gene Med) Vol. 8 Issue 6 Pg. 707-18 (Jun 2006) ISSN: 1099-498X [Print] England
• PMID: 16518880 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2006 John Wiley & Sons, Ltd.

Chemical References

• DNA, Viral
• Photosensitizing Agents
• RNA, Messenger
• enhanced green fluorescent protein
• Green Fluorescent Proteins
• beta-Galactosidase

Topics

• Adenoviridae (drug effects, genetics, isolation & purification)
• Cell Line, Tumor
• Cell Nucleus (drug effects, radiation effects, virology)
• DNA, Viral (genetics)
• Endosomes (metabolism)
• Gene Expression (radiation effects)
• Genome, Viral (genetics)
• Green Fluorescent Proteins (genetics)
• HCT116 Cells
• Humans
• Photosensitizing Agents (metabolism, pharmacology)
• RNA, Messenger (genetics, metabolism)
• Time Factors
• Transduction, Genetic
• Transgenes
• Tumor Cells, Cultured
• beta-Galactosidase (genetics)