人脑胶质瘤细胞株MGR2放射抗拒性的诱导  

Radioresistant Subline of Human Glioma Cell Line MGR2R Induced by Repeated High Dose X-ray Irradiation

作　　者：程金建[1] 胡震[1] 夏云飞[1] 陈忠平[1] 

机构地区：[1]华南肿瘤学国家重点实验室

出　　处：《癌症》2006年第1期45-50,共6页Chinese Journal of Cancer

基　　金：国家自然科学基金(No.30500528);中山大学重点学科建设基金;中山大学CMB基金(No.98-677)~~

摘　　要：背景与目的:放射治疗是脑胶质瘤重要辅助治疗手段之一,但脑胶质瘤放射敏感性存在很大差异。本研究通过对放射相对敏感的人脑胶质瘤细胞株进行放射诱导得到具有稳定放射抗拒性的后代细胞,从而为研究胶质瘤放射抗拒机制提供具有可比性的成对细胞。方法:选取对X射线相对敏感的人脑胶质瘤细胞株MGR2[2Gy照射下的存活分数(survivalfractionof2Gy,SF2)为0.180±0.05]进行间歇性大剂量X射线照射(每次2Gy,共3次,而后每次5Gy,共2次),每次照射后的细胞继续培养,待5～8周存活的细胞状态稳定后进行下一次照射,整个照射及培养过程历时11个月,最终得到的后代细胞命名为MGR2R(MGR2radiationinduction)。采用MTT法检测MGR2和MGR2R细胞生长的倍增时间,平板集落形成法和线性二次模型(L-Q模型)拟合MGR2和MGR2R细胞的存活曲线并计算相关放射生物学参数和SF2值。血清饥饿细胞周期同步化方法检测MGR2和MGR2R的细胞周期变化。结果:MGR2的倍增时间为3.6天,MGR2R的生长速度减慢,倍增时间为4.0天。MGR2和MGR2R的α值分别为0.447和0.089(t=4.524,P=0.011),β值分别为0.177和0.141(t=1.562,P=0.193),SF2值为0.208和0.478(t=-6.062,P=0.040),MGR2R的放射抗拒性增加。细胞周期同步化后MGR2的细胞周期分布为G1期54.8%,S期30.9%,G2期14.3%,去同步化后G1期35.9%,S期51.2%,G2期12.8%,MGR2R正常生长时存在G2期阻滞(81.7%),同步化后G1期55.7%,S期27.8%,G2期16.6%,去同步化后分别为G1期56.4%,S期26.7%,G2期16.9%,MGR2R存在G1期阻滞,去同步化后两者细胞周期改变不同。结论:人脑胶质瘤细胞株MGR2经间歇性大剂量X射线多次照射后得到的后代细胞MGR2R具有稳定放射抗拒性。MGR2R生长速度减慢,倍增时间延长,同时存在G1和G2期阻滞,可能与其放射抗拒性的产生有关。BACKGROUND ＆ OBJECTIVE： Radiotherapy is one of the most important adjuvant treatments for patients with malignant glioma, but radiosensitivities of gliomas are widely various. This study was to induce human glioma cell line MGR2 to become a stable radioresistant cell subline, and investigate the mechanisms of radioresistance. METHODS： Human glioma cell line MGR2, with survival fraction of 2 Gy （SF2） of 0.18±0.05, was irradiated by intermittent high dose X-ray （2 Gy for 3 times, 5 Gy for 2 times）. After each irradiation, the cells were cultured for 5 to 8 weeks and received irradiation again. The whole process of irradiation and culture lasted for 11 months. The cells derived from MGR2 were obtained and named MGR2R （MGR2 radiation induction）. Double times of MGR2 and MGR2R cells were determined by MTT assay. Dose-survival curves, radiobiological parameters and SF2 were determined by colony-forming assay and linequadratic model. The variation of their cell cycles was investigated by flow cytometry and cell cycle synchronization of serum-starvation. RESULTS.. The double time of MGR2 cells was 3.6 days, while that of MGR2R cells was 4.0 days. The growth rate of MGR2R cells was slower than that of MGR2 cells. Using colony-forming assay and line-quadratic model, the parameters of MGR2 and MGR2R were obtained. The a values of MGR2 and MGR2R were 0.447 and 0.089 （t=4.524, P=0.011）, the （5 values were 0.177 and 0.141 （t=1.562, P=0.193）, and the SF2 were 0.208 and 0.478 （t=-6.062, P= 0.040）, respectively. The radioresistance of MGR2R cells was stronger than that of MGR2 cells. The distribution of cell cycle in MGR2 cells after synchronization were 54.8% in G1 phase, 30.9% in S phase, and 14.3% in G2 phase; 24 h after loss of synchronization, the distribution of cell cycle were 35.9% in G1 phase, 51.2% in S phase, and 12.8% in G2 phase. The distribution of cell cycle in MGR2R cells after synchronization were 55.7% in G1 phase, 27.8% in S phase, and 16.6% in G2 phase; 24 h after loss of synch

关 键 词：脑肿瘤 胶质细胞瘤 放射抗拒性 细胞周期 

分 类 号：R739.4[医药卫生—肿瘤]