鳞癌细胞株放射敏感性与端粒酶活性及端粒长度变化的关系  

Relationship between radiosensitivity of human squamous carcinoma cell lines and changes in telomerase activity and telomere length

作　　者：骆志国[1] 周福祥[1] 周云峰[1] 谢丛华[1] 代静[1] 潘东风[1] 刘诗权[2] 

机构地区：[1]武汉大学中南医院肿瘤放化疗科 [2]武汉大学医学院肿瘤研究所

出　　处：《中华放射医学与防护杂志》2005年第3期232-235,共4页Chinese Journal of Radiological Medicine and Protection

基　　金：湖北省自然科学基金资助项目(2001J092;2004ABA165)

摘　　要：目的探索放射抗拒鳞癌细胞株放射敏感性的改变与端粒酶活性、端粒长度变化的关系。方法以人喉鳞癌细胞株Hep2为实验对象,用γ射线反复照射获得具有放射抗拒性细胞株Hep2R,拟合细胞存活曲线比较两种细胞株的放射生物学参数及端粒酶抑制剂AZT(azidothymidine,叠氮胸苷)作用后的变化,用TRAP-ELISA法测定端粒酶活性(OD值),Southernblotting法分析端粒平均长度(TRF),比较端粒酶活性、端粒平均长度的变化。结果辐射诱导出一个具有放射抗拒性的Hep-2R细胞株,并已稳定传代培养30代以上且放射抗拒性能稳定,测得其SF2=0.6798、D0=3.24,Hep-2R细胞的端粒酶活性较Hep-2细胞升高(0.982±0.005vs0.604±0.015),端粒长度延长了2倍(11.12kbvs3.76kb),AZT作用后Hep2R细胞株SF2=0.4892、D0=2.51,端粒酶活性下降为0.708±0.011、端粒长度缩短为10.18kb。Hep2细胞对应的参数SF2=0.4148、D0=2.06,AZT作用后Hep2细胞SF2=0.3843、D0=1.81,端粒酶活性下降为0.364±0.003、端粒长度缩短为2.76kb。结论辐射诱导细胞获放射抗拒性后其端粒酶活性升高、端粒平均长度增长,端粒酶抑制剂能通过降低端粒酶活性、缩短端粒长度而对其有增敏效应。Objective To investigate the changes in radiosensitivity, telomerase activity, telomere length in a radiation-induced radioresistant cell line of human squamous carcinoma and its parent cell line. Methods A radioresistant cell line, Hep-2R, was isolated from a radiosensitive human laryngeal squamous carcinoma cell line Hep-2 by repeated γ-irradiation. The radiobiological characteristics,in the presence or absence of telomerase inhibitor AZT, of both cell lines were analysized by means of clonogenic assay. Radiosesitivity coefficients were calculated. The telomerase activity was examined by the PCR-based telomeric repeat amplification protocol(TRAP) and the telomere length(mean length for telomere restriction fragments, TRF) by Southern blotting. Results A radioresistant cell line, Hep-2R, was obtained after prolonged exposure to γ-rays for 7 months and has been already maintained for more than 30 generations. The radioresistance of Hep-2R cell line was proved to be stable in long-term subculturing as well as in frozen samples. The SF_2, D_0, telomerase activity, TRF for Hep-2R cell line were 0.6798, 3.24, 0.982±0.0005, 11.12, respectively and were 0.4148, 2.06, 0.604±0.015, 3.76 for Hep-2 cell line. After treated with AZT, the SF_2, D-0, telomerase activity, TRF for Hep-2R cell line were turned to be 0.4892, 2.51, 0.708±0.011, 10.18,respectively and were 0.3843, 1.81, 0.364±0.0003, 2.76 for Hep-2. Conclusion Hep-2R cell line is stably radioresistant. The telomerase activity is increased and telomere length is lengthened in the radiation-induced radioresistant Hep-2R cell line. Telomerase inhibitor AZT could increase the susceptibility of the cell line to radiation by down-regulating telomerase activity and shortening telomere length. ;

关 键 词：端粒酶活性 放射敏感性 癌细胞株 长度变化 TRAP-ELISA法 Hep-2细胞 blotting 端粒酶抑制剂 放射生物学参数 放射抗拒 端粒长度 细胞存活曲线 辐射诱导 实验对象 叠氮胸苷 传代培养 增敏效应 AZT γ射线 OD值 平均 缩短 

分 类 号：R73-36[医药卫生—肿瘤]