Membrane lipid free radicals produced from L1210 murine leukemia cells by photofrin photosensitization: an electron paramagnetic resonance spin trapping study.
We have detected membrane lipid-derived free radicals from neoplastic cells subjected to Photofrin photosensitization. The presence of the prooxidants iron or iron plus ascorbate in the L1210 cell system increased the intensity of the spin-trapped lipid radical electron paramagnetic resonance spectra and correspondingly decreased cell survival. In addition, raising the proportion of unsaturated lipids in the cell membranes by supplementation of the growth medium with docosahexaenoic acid increased lipid radical formation and decreased cell survival when the L1210 cells were subjected to Photofrin and light. These data educe the hypothesis that the extent of radical generation as well as the efficacy of photodynamic therapy can be increased when prooxidant conditions, which enhance free radical processes, are present in conjunction with photosensitizers that target membrane lipids.
Department of Medicine, College of Medicine, University of Iowa, Iowa City 52242.
G R
GR
Buettner
E E
EE
Kelley
C P
CP
Burns
D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000378:metabolism; D017324:Hematoporphyrin Derivative / Q000494:pharmacology*; D007501:Iron / Q000494:pharmacology; D007939:Leukemia L1210 / Q000188:drug therapy / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism*; D051379:Mice; D010778:Photochemotherapy
D005609:Free Radicals; D008563:Membrane Lipids; D017324:Hematoporphyrin Derivative; D007501:Iron; D001205:Ascorbic Acid