Phototoxic effects of fluorescent protein KillerRed on tumor cells in mice

J Biophotonics. 2013 Mar;6(3):283-90. doi: 10.1002/jbio.201200056. Epub 2012 Jun 13.


KillerRed is known to be a unique red fluorescent protein displaying strong phototoxic properties. Its effectiveness has been shown previously for killing bacterial and cancer cells in vitro. Here, we investigated the photototoxicity of the protein on tumor xenografts in mice. HeLa Kyoto cell line stably expressing KillerRed in mitochondria and in fusion with histone H2B was used. Irradiation of the tumors with 593 nm laser led to photobleaching of KillerRed indicating photosensitization reaction and caused significant destruction of the cells and activation of apoptosis. The portion of the dystrophically changed cells increased from 9.9% to 63.7%, and the cells with apoptosis hallmarks from 6.3% to 14%. The results of this study suggest KillerRed as a potential genetically encoded photosensitizer for photodynamic therapy of cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Transformation, Neoplastic
  • Chromatin / drug effects
  • Chromatin / metabolism
  • Chromatin / radiation effects
  • Female
  • HeLa Cells
  • Histones / metabolism
  • Humans
  • Luminescent Proteins / metabolism
  • Luminescent Proteins / pharmacology*
  • Mice
  • Mice, Nude
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Mitochondria / radiation effects
  • Molecular Imaging
  • Photosensitizing Agents / metabolism
  • Photosensitizing Agents / pharmacology*
  • Protein Transport
  • Red Fluorescent Protein


  • Chromatin
  • Histones
  • Luminescent Proteins
  • Photosensitizing Agents