SUN Yu-lan,HU Yi-de,QIAN Hai-hong.Apoptosis and down-regulated expression of mitochondrial DNA genes in A549 cells induced by X-ray irradiation[J].Chinese Journal of Radiological Medicine and Protection,2007,27(5):433-437 |
Apoptosis and down-regulated expression of mitochondrial DNA genes in A549 cells induced by X-ray irradiation |
Received:October 16, 2006 |
DOI: |
KeyWords:Mitochondrial DNA Apoptosis Cell cycle arrest Gene expression |
FundProject:国家自然科学基金资助项目(30080030);全军“十一五”医药卫生基金攻关课题资助项目(06G068) |
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Abstract:: |
Objective To investigate the apoptotic effect and differential expression of mitochondrial DNA(mtDNA) genes in A549 human lung adenocarcinoma at different doses of X-ray irradiation. Methods A549 cells were irradiated with 8 MV X rays at the absorbed doses of 2,4,6 or 8 Gy, and then cultured for 24 h. Cell proliferation was detected by MTT assay. Cell cycle distribution and apoptotic rates were determined by flow cytometry (FCM). The apoptotic morphology was observed by transmission electron microscope (TEM). The differential expression of mtDNA genes were detected with mtDNA oligonucleotide microarray. Results The proliferation of A549 cells was inhibited by X irradiation,especially at 4 Gy. Dose-dependent apoptosis and cell percentage increase of G2/M phase were displayed,while the apoptotic morphological characters were observed at 4 Gy group. Down_regulation of Expression of 3 tRNA genes, 2 tRNA genes and 4 mRNA genes, 6 tRNA genes and 1 rRNA gene,2 tRNA genes, which were all encoded by mtDNA, were identified at groups 2,4,6 and 8 Gy, respectively. Conclusions After exposure to X-ray, proliferative inhibition and apoptosis, as well as down-regulated expression of mitochondrial DNA genes were observed in A549 cells and 4 Gy may be regarded as an effective and safe dose in vitro. |
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