着丝粒蛋白F mRNA在肺腺癌细胞系、肺腺癌组织中的表达变化及相关调控信号通路分析

目的观察着丝粒蛋白F(CENPF) mRNA在肺腺癌细胞系中的表达变化,分析CENPF mRNA在肺腺癌组织中的表达变化并探讨其相关调控信号通路。方法①采用实时定量PCR法检测肺正常上皮细胞系BEAS-2B、肺腺癌细胞系(A549、NCI-H1650、NCI-H23、NCI-H1975) CENPF mRNA。②采用癌症基因组图谱(TCGA)的肺腺癌数据集分析CENPF mRNA表达与肺腺癌临床病理参数、预后的关系,Cox回归模型分析肺腺癌患者预后的影响因素。③采用基因集富集分析(GSEA)法分析受CENPF调控的肺腺癌相关信号通路。结果①A549、NCI-H1650、NCI-H23、NCI-H1975、BEAS-2B细胞CENPF mRNA相对表达量分别为4. 333±0. 271、3. 193±0. 188、2. 770±0. 091、5. 491±0. 249、1. 006±0. 071,A549、NCI-H1650、NCI-H23、NCI-H1975细胞CENPF mRNA相对表达量均高于BEAS-2B(P均<0. 05)。②肺腺癌、癌旁正常组织CENPF mRNA的相对表达量分别为9. 632±0. 059、6. 472±0. 093,二者比较,P <0. 001。CENPF mRNA表达与肺腺癌患者的性别、年龄、T分期、N分期及TNM分期相关(P均<0. 05)。生存分析结果显示,与CENPF mRNA低表达患者比较,CENPF mRNA高表达的肺腺癌患者的预后差(P=0. 001)。CENPF mRNA表达、临床TNM分期(HR分别为1. 667,1. 414; P均<0. 01)是影响肺腺癌患者预后的因素。③与CENPF mRNA高表达有关的肺腺癌调控信号通路有G2M检查点(P <0. 001,FDR <0. 001)、有丝分裂纺锤体(P <0. 001,FDR <0. 001)、E2F靶基因(P <0. 001,FDR <0. 001)、MYC靶基因(P <0. 001,FDR=0. 001)、m TOR信号通路(P=0. 002,FDR=0. 005)、精子形成(P=0. 002,FDR=0. 009)、未折叠蛋白反应(P=0. 002,FDR=0. 020)及PI3K/Akt/m TOR信号通路(P=0. 015,FDR=0. 117)等。结论肺腺癌组织及细胞系中存在CENPF高表达,CENPF高表达与肺腺癌患者的恶性病理特征及不良预后密切相关。CENPF mRNA高表达是影响肺腺癌患者预后的独立危险因素。CENPF可能通过调节G2M检查点、有丝分裂纺锤体、E2F靶基因、MYC靶基因、m TOR信号通路、精子形成、未折叠蛋白反应及PI3K/Akt/m TOR信号通路在肺腺癌的发生、发展中起重要作用。

The Role of DNA Damage Repair and Chk2 Protein in Hyper-radiosensitivity of Lung Adenocarcinoma A549 Cells

To explore the role of the Chk2 protein expression and DNA double strand breaks (DSBs) repair in low dose hyper-radiosensitivity (HRS)/increased radioresistance (IRR) of non-small cell lung cancer,A549 cells were subjected to irradiation at the dosage ranging from 0.05-2 Gy.Clonogenic survival was measured by using fluorescence-activated cell sorting (FACS) plating technique.Percentage of cells in M-phase after low doses of X-irradiation was evaluated by phospho-histone H3-FITC/PI and Western blotting was used to detect protein expression of Chk2 and phospo-Chk2.DNA DSBs repair efficiency was also measured by induction and persistence of γ-H2AX.The results showed that the killing ability of irradiation with A549 cells increased at low conditioning dose below 0.3 Gy.Within the dose of 0.3 to 0.5 Gy,A549 cells showed a certain extent of radiation resistance.And when the dose was more than 0.5 Gy,survival fraction exhibited a negative correlation with the dosage.There was no difference between the 0.1 or 0.2 Gy dosage groups and the un-irradiated group in terms of the percentage of cells in M phase.But in the high dosage group (0.3-1.0 Gy),the percentage of cells in M phase was decreased markedly.In addition,the percentage of cells in M phase began to decrease two hours after irradiation.One hour after irradiation,there was no conspicuous activation of Chk2 kinase in 0.1 or 0.2 Gy group,but when the irradiation dose reached 0.3 Gy or higher,Chk2 kinase started to be activated and the activation level showed no significant difference among high dosage groups (0.4,0.5,1.0 Gy).Within 1 to 6 h,the DNA DSBs repair efficiency was decreased at 0.2 Gy but increased at 0.5 Gy and 1.0 Gy,which was in line with Chk2 activation.We are led to conclude that the mechanism of HRS/IRR in A549 cell line was probably due to early G2/M checkpoint arrest and enhanced DNA DSBs repair.In this regard,Chk2 activation plays a key role in G2/M checkpoint activation.