Sites of photodynamically induced DNA repair in human cells.
Human REH cells were incubated with the photosensitizers meso-tetra(4-sulfonatophenyl)porphyrin (TSPP = TPPS4) or meso-tetra(3-hydroxyphenyl)porphyrin (3-THPP). The relatively hydrophilic TSPP was partly found in the cytoplasm and partly in the nuclei, whereas the lipophilic 3-THPP was found apparently in membranes and not inside the nuclei. After illumination, sites of DNA repair were labeled by means of a monoclonal antibody against proliferating cell nuclear antigen (PCNA) bound in the nuclei. The amount of bound PCNA in non-S-phase cells was proportional to the light dose. The bound PCNA was homogeneously distributed in the nuclei 0.5 h after photodynamic treatment (PDT) with TSPP. In contrast, for cells given PDT with 3-THPP, the periphery of the nuclei was selectively labeled, indicating that the initial DNA damage was localized close to the sensitizer at the nuclear membrane.
Kvam
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E
Department of Biophysics, Norwegian Radium Hospital, Montebello, Oslo, Norway.
Stokke
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T
D001402:B-Lymphocytes / Q000187:drug effects; D002478:Cells, Cultured; D004260:DNA Repair / Q000187:drug effects*; D006801:Humans; D008027:Light; D009687:Nuclear Proteins / Q000032:analysis; D017319:Photosensitizing Agents / Q000494:pharmacology*; D018809:Proliferating Cell Nuclear Antigen
D009687:Nuclear Proteins; D017319:Photosensitizing Agents; D018809:Proliferating Cell Nuclear Antigen