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

J Gene Med. 2006 Jun;8(6):707-18. doi: 10.1002/jgm.902.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

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


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