tailieunhanh - Báo cáo khoa học: Photodynamic treatment and H2O2-induced oxidative stress result in different patterns of cellular protein oxidation

Photodynamic treatment (PDT) is an emerging therapeutic procedure for the management of cancer, based on the use of photosensitizers, compounds that generate highly reactive oxygen species (ROS) on irradiation with visible light. The ROS generated may oxidize a variety of bio-molecules within the cell, loaded with a photosensitizer. The high reactivity of these ROS restricts their radius of action to 5–20 nm from the site of their generation. | Eur. J. Biochem. 270 4859-4865 2003 FEBS 2003 doi Photodynamic treatment and H2O2-induced oxidative stress result in different patterns of cellular protein oxidation Dmitri V. Sakharov1 Anton Bunschoten1 Huib van Weelden2 and Karel W. A. Wirtz1 1 Department of Biochemistry of Lipids Centre for Biomembranes and Lipid Enzymology Institute of Biomembranes Utrecht University the Netherlands department of Photodermatology University Medical Center Utrecht the Netherlands Photodynamic treatment PDT is an emerging therapeutic procedure for the management of cancer based on the use of photosensitizers compounds that generate highly reactive oxygen species ROS on irradiation with visible light. The ROS generated may oxidize a variety of biomolecules within the cell loaded with a photosensitizer. The high reactivity of these ROS restricts their radius of action to 5-20 nm from the site of their generation. We studied oxidation of intracellular proteins during PDT using the ROS-sensitive probe acetyl-tyramine-fluorescein acetylTyr-Fluo . This probe labels cellular proteins which become oxidized at tyrosine residues under the conditions of oxidative stress in a reaction similar to dityrosine formation. The fluorescein-labeled proteins can be visualized after gel electrophoresis and subsequent Western blotting using the antibody against fluorescein. We found that PDT of rat or human fibroblasts loaded with the photosensitizer Hypocrellin A resulted in labeling of a set of intracellular proteins that was different from that observed on treatment of the cells with H2O2. This difference in labeling patterns was confirmed by 2D electrophoresis showing that a limited yet distinctly different set of proteins is oxidized under either condition of oxidative stress. By matching the Western blot with the silver-stained protein map we infer that a-tubulin and b-tubulin are targets of PDT-induced protein oxidation. H2O2 treatment resulted in labeling of .