SITES OF PHOTODYNAMICALLY INDUCED DNA REPAIR IN HUMAN CELLS |
| |
Authors: | Egil Kvam Trond Stokke |
| |
Institution: | Department of Biophysics, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway |
| |
Abstract: | Abstract 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. |
| |
Keywords: | |
|
|