Xu Desheng, Jia Qiang, Li Yanhe, Kang Chunsheng, Pu Peiyu
Department of Neurosurgery, Tianjin Medical University 2nd Hospital, Tianjin, Republic of China.
J Neurosurg. 2006 Dec;105 Suppl:208-13. doi: 10.3171/sup.2006.105.7.208.
The authors sought to study the combined potential of wild-type p53 gene transfer and Gamma Knife surgery (GKS) for the treatment of glioblastomas multiforme. Modification of the radiation response in C6 glioma cells in vitro and in vivo by the wild-type p53 gene was investigated.
Stable expression of wild-type p53 in C6 cells was achieved by transduction of the cells with adenoviral p53. Two days later, some cells were treated with GKS. Forty-eight hours after irradiation, the comparative survival rate was assessed by monotetrazolium (MTT) assays. Treated and control C6 glioma cells (4 x 10(3) per well) were plated into a 96-well plate in octuplicate and tested every 24 hours. Meanwhile, immunohistopathological examination of proliferating cell nuclear antigen (PCNA) and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (TUNEL) assays were performed. The MTT assays indicated the p53, GKS, and combined treated cells proliferated at a significantly lower rate than those of the control group (p < 0.01, Days 2-6) and the positive fraction of PCNA in p53-treated group and GKS-treated group was 70.18 +/- 3.61 and 50.71 +/- 2.61, respectively, whereas the percentage in the combined group was 30.68 +/- 1.49 (p < 0.01). Fifty-six male Sprague-Dawley rats were anesthetized and inoculated with 10(6) cultured C6 glioma cells into the cerebrum. Forty-eight hours after transduction with adenoviral p53, some rats underwent GKS. A margin dose of 15 Gy was delivered to the 50% isodose line. Two days later, six rats in each group were killed. Their brains were removed and paraffin-embedded section were prepared for immunohistopathological examination and TUNEL assays. The remaining rats were observed for the duration of the survival period. The survival curve indicated that a modest but significant enhancement of survival duration was seen in the p53-treated or GKS alone groups, whereas a more marked and highly significant enhancement of survival duration was achieved when these two treatment modalities were combined. When PCNA expression was downregulated, apoptotic cells become obvious after TUNEL staining.
The findings of this study suggest that p53-based gene therapy in combination with GKS may be superior to single-modality treatment of C6 glioma.
作者试图研究野生型p53基因转移与伽玛刀手术（GKS）联合治疗多形性胶质母细胞瘤的潜在效果。研究了野生型p53基因在体外和体内对C6胶质瘤细胞辐射反应的影响。
通过腺病毒p53转导使野生型p53在C6细胞中稳定表达。两天后，对部分细胞进行GKS治疗。照射48小时后，通过四甲基偶氮唑盐（MTT）法评估相对存活率。将处理过的和对照的C6胶质瘤细胞（每孔4×10³个）以八重复接种到96孔板中，每24小时检测一次。同时，进行增殖细胞核抗原（PCNA）的免疫组织病理学检查和末端脱氧核苷酸转移酶介导的脱氧尿苷三磷酸（TUNEL）检测。MTT检测表明，p53、GKS及联合处理组细胞的增殖率明显低于对照组（第2 - 6天，p < 0.01），p53处理组和GKS处理组PCNA的阳性率分别为70.18±3.61和50.71±2.61，而联合组为30.68±1.49（p < 0.01）。将56只雄性Sprague-Dawley大鼠麻醉后，向大脑接种10⁶个培养的C6胶质瘤细胞。用腺病毒p53转导48小时后，部分大鼠接受GKS治疗。向50%等剂量线给予15 Gy的边缘剂量。两天后，每组处死6只大鼠。取出大脑，制备石蜡包埋切片用于免疫组织病理学检查和TUNEL检测。其余大鼠观察生存期。生存曲线表明，单独p53治疗组或GKS组的生存期有适度但显著的延长，而这两种治疗方式联合使用时，生存期延长更为显著且具有高度统计学意义。当PCNA表达下调时，TUNEL染色后凋亡细胞明显增多。
本研究结果表明，基于p53的基因治疗联合GKS可能优于C6胶质瘤的单一治疗方式。
