Fiche publication
Date publication
janvier 2007
Journal
Journal of environmental pathology, toxicology and oncology : official organ of the International Society for Environmental Toxicology and Cancer
Auteurs
Membres identifiés du Cancéropôle Est :
Dr LASSALLE Henri-Pierre
Tous les auteurs :
Lassalle HP, Baumann H, Strauss WS, Schneckenburger H
Lien Pubmed
Résumé
Because of the low penetration depth of an evanescent electromagnetic field, total internal reflection fluorescence microscopy (TIRFM) proved to be a powerful technique to examine fluorescent dyes or photosensitizers in close vicinity to the plasma membrane of living cells. In addition, on variation of the angle of incidence of exciting laser light, the penetration depth is varied, so that cell-substrate topology can be examined with nanometer resolution. Using a specific illumination device for TIRFM and a highly sensitive electron multiplying (EM) CCD camera, fluorescence of the photosensitizer protoporphyrin IX (PPIX) was studied in human cancer cells after application of 5-aminolevulinic acid (5-ALA) prior to and after irradiation with sublethal light doses (635 nm, 4 J/cm2). For cells growing on microscope cover slides, cell-substrate distances varied between approximately 20 and 250 nm with a mean distance of approximately 120 nm. On light exposure, these distances generally decreased, and a mean value below 100 nm was attained. Moreover, focal contacts visualized with a fusion protein of yellow fluorescent protein and focal adhesion kinase were maintained on light exposure, i.e., light-induced detachment of cells from their substrate was not likely to occur.
Mots clés
Aminolevulinic Acid, pharmacology, Brain Neoplasms, drug therapy, Cell Line, Tumor, Cell Membrane, drug effects, Drug Screening Assays, Antitumor, Female, Glioblastoma, drug therapy, HeLa Cells, drug effects, Humans, Microscopy, Fluorescence, instrumentation, Photochemotherapy, Photosensitizing Agents, pharmacology, Protoporphyrins, metabolism
Référence
J. Environ. Pathol. Toxicol. Oncol.. 2007 ;26(2):83-8
