DNA损伤修复因子乳腺癌易感基因1对雷公藤甲素诱导肺癌细胞凋亡的作用研究

Effect of DNA damage repair factor breast cancer susceptibility gene 1 on triptolide-induced lung cancer cell apoptosis

目的探讨DNA损伤修复因子乳腺癌易感基因1(BRCA1)对雷公藤甲素(TP)诱导非小细胞肺癌凋亡的影响。方法将A549细胞随机分为模型组和空白组,模型组用50μg·L-1的TP处理,空白组用相同体积的二甲基亚砜(DMSO)溶剂处理。同时,将pCMV6-Control和pCMV6-BRCA1分别转染至模型组,分别命名为阴性对照组和实验组。用免疫印迹法检测BRCA1蛋白表达,用单细胞凝胶电泳技术(彗星实验)检测各组细胞的DNA损伤的状态,用Annexin V-FITC/PI标记法检测不同DNA损伤状态下的肺癌细胞凋亡率。结果空白组、模型组、阴性对照组、实验组的BRCA1蛋白相对表达量分别为1.32±0.21,0.34±0.09,0.58±0.11,1.24±0.22;拖尾细胞率分别为(1.09±0.11)%,(56.90±4.42)%,(58.30±4.47)%,(27.95±2.55)%;拖尾长度分别为(2.15±0.65),(80.50±6.55),(76.10±5.50),(41.35±4.45)μm;空白组、模型组、阴性对照组、实验组的细胞凋亡率分别为(7.03±1.72)%,(55.38±2.82)%,(53.46±3.40)%,(32.35±3.57)%。以上指标,模型组、阴性对照组、实验组分别与空白组比较,阴性对照组与实验组比较,差异有统计学意义(P<0.05);实验组与空白组比较,差异均有统计学意义(P<0.05,P<0.01)。结论TP通过降低BRCA1的表达引发肺癌细胞DNA损伤进而诱导细胞凋亡。

Objective To investigate whether DNA damage repair factor breast cancer susceptibility gene 1(BRCA1)affects triptolide-induced apoptosis in non-small cell lung cancer.Methods A549 cells were randomly divided into model group and blank group,the model group was treated with 50μg·L-1 of TP,the blank group was treated with the same volume of DMSO.The apoptosis of lung cancer cells was detected by Annexin V-FITC/PI,and western blotting was used to detect protein expression.Meanwhile,pCMV6-control and pCMV6-BRCA1 were transfected into the model group and respectively named as negative control group and experimental group.The expression of BRCA1 in each group was detected by western blotting,DNA damage in each group was detected by single cell gel electrophoresis(Comet assay),and the apoptosis in each group was detected by Annexin V-FITC/PI labeling.Results The relative protein expressions of BRCA1 in blank group,model group,negative control group,and experimental group were 1.32±0.21,0.34±0.09,0.58±0.11,1.24±0.22;The comet cell rates of blank group,model group,negative control group,and experimental group were(1.09±0.11)%,(56.90±4.42)%,(58.30±4.47)%,(27.95±2.55)%;the tail lengths of blank group,model group,negative control group,and experimental group were(2.15±0.65),(80.50±6.55),(76.10±5.50),(41.35±4.45)μm;the apoptosis rates of blank group,model group,negative control group,and experimental group were(7.03±1.72)%,(55.38±2.82)%,(53.46±3.40)%,(32.35±3.57)%.For the above results,the differences between blank group and model group,negative control group,experimental group were statistically significant(P<0.05),and the differences between negative control group and experimental group were statistically significant(P<0.05,P<0.01).Conclusion Triptolide induced apoptosis by reducing BRCA1 expression which further evoking DNA damage.