电离辐射联合顺铂对人肺癌细胞中BTG3基因表达的影响

加速器产生的6-MV X-射线一次性照射体外培养的人肺腺癌细胞株A549和SPCA-1,细胞的吸收剂量分别设置为0、1、3、5和8 Gy,细胞照射后24 h及单次接受5 Gy照射后6、12和24 h后取样;X-射线联合顺铂对BTG3表达的影响研究设立单纯照射组(5 Gy)、顺铂处理组(20μmol·L-1顺铂)和联合处理组(5 Gy+20μmol·L-1顺铂),上述实验均以未给予任何处理的细胞为对照组;采用Western blot及RT-PCR法检测受到不同剂量电离辐射及照射后不同时间肿瘤细胞中BTG3表达水平。Western blot与PCR检测结果均显示,A549和SPCA-1细胞在受到不同剂量的X-射线照射后24 h,其BTG3蛋白及mRNA表达量均明显增加,并随电离辐射剂量的增加而增加,与对照组比较有统计学差异(t=5.25-15.75,p0.05);照射后不同时间检测结果显示,细胞在X-射线照射4 h后BTG3蛋白及mRNA的表达量即开始上升,并持续到照射后24 h,与照射前相比有统计学差异(t=7.52-11.18,p0.05);联合处理组BTG3的表达量均明显高于单纯照射组、顺铂处理组和对照组(t=7.02-15.86,p0.05)。电离辐射联合顺铂可以上调肺癌细胞株中BTG3的表达,BTG3基因有可能作为肺癌放化疗的靶基因。

Effects of ionizing radiation and cisplation on the expression of BTG3 in human lung cancer cell lines

Human lung cancer A549 and SPCA- 1 cell lines were irradiated by X-rays at the absorbed doses of 1, 3, 5 and 8 Gy, respectively, generated by a linear accelerator （with the source skin distance of 100 cm and dose rate of 200 cGy＇minX）. The cell molecular samples were subtracted at 6 h, 12 h, and 24 h after 5 Gy ionizing irradiation. For the study of X-rays and cisplatin combination treatment, cells were divided into radiation group （5 Gy X-rays）, cisplatin group （20 gmol-L-1 cisplatin）, and combination group （5 Gy X-rays ＋ 20 pmol-L 1 cisplatin）. Untreated cells were classified as control group. The relative levels of BTG3 mRNA and protein expression in cells were detected by semi-quantitative RT-PCR and Western blot analysis with quantitation of the mRNA/protein bands by densitometry. The expression level of BTG3 mRNA and protein significantly increased with the dose climbed after radiation exposure of human lung cancer A549 and SPCA-1 cell lines （t=-5.25-15.75, p〈0.05）. The expression level in cancer cells significantly increased 4 h after radiation exposure and kept increasing until 24 h later （t=-7.52-11.18, p〈0.05）. Compared with that of the radiation and/or cisplatin treatment alone, more significant increase of BTG3 expression was identified after the combination treatment of X-rays and cisplatin （t=-7.02-15.86, p〈0.05）. Ionizing radiation could up-regulate the expression of BTG3 in human lung cancer cells in both mRNA and protein levels. BTG3 gene may be targeted as a molecular for ionizing radiation and cisplatin treatment in lung cancer.