Apoptosis induced by high-LET radiations is not affected by cellular p53 gene status

• Published in: International journal of radiation biology Vol. 81; no. 8; pp. 581 - 586
• Main Authors: Takahashi, A., Matsumoto, H., Furusawa, Y., Ohnishi, K., Ishioka, N., Ohnishi, T.
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 01.08.2005; Taylor & Francis
• Subjects: apoptosis; Apoptosis - genetics; Apoptosis - radiation effects; Fe ion beams; Genes, p53; Humans; linear energy transfer (LET); Lung Neoplasms - genetics; Lung Neoplasms - pathology; Microscopy, Fluorescence; Radiation Tolerance; Space life sciences; Tumor Cells, Cultured; X-Rays
• ISSN: 0955-3002; 1362-3095
• DOI: 10.1080/09553000500280484

To learn more about the biological effects of high-linear energy transfer (LET) radiations, we examined radiation-induced apoptosis in response to high-LET radiations in cells with wild-type, mutated and null p53 gene. Three human lung cancer cell lines were used. These lines had identical genotypes, except for the p53 gene. Cells were exposed to X-rays or high-LET radiations (13 - 200 keV μm−1) using different nuclei ion beams. Cellular radiation sensitivities were determined with the use of colony-forming assays. Apoptosis was detected and quantified using Hoechst 33342 staining with fluorescence microscopy. It was found that (1) there was no significant difference in cellular sensitivity to high-LET radiation (>85 keV μm−1), although the sensitivity of wild-type p53 cells to X-rays was higher than that of mutated p53 or p53-null cells; (2) X-ray-induced apoptosis at higher frequencies in wild-type p53 cells when compared with mutated p53 and p53-null cells; and (3) Fe beams (200 keV μm−1) induced apoptosis in a p53-independent manner. The results indicate that high-LET radiations induces apoptosis in human lung cancer cells in a manner that does not seem to depend on the p53 gene status of the cells.