目的 分析人脑胶质瘤组织中O6—甲基鸟嘌呤—DNA甲基转移酶(MGMT)、DNA拓扑异构酶Ⅱ(TopoⅡ)基因的表达情况及其对化疗敏感性的影响。方法 收集医院2012年4月—2018年6月期间进行开颅手术切除的新鲜人脑胶质瘤标本80例和同期经颅脑手术治疗的脑外伤或脑出血内减压切除的正常脑组织30例。采用免疫组化法检测两种标本中MGMT和TopoⅡ基因表达情况,并通过脑胶质瘤U251和U87细胞培养、体外药物(替莫唑胺)干预、Transwell体外侵袭实验分析其对化疗敏感性的影响。结果 胶质瘤标本、正常脑组织MGMT和TopoⅡ基因表达程度分布比较差异均有统计学意义(P＜0.05),且二者MGMT基因阳性表达率分别为63.75%、3.33%,TopoⅡ基因阳性表达率分别为55.00%、0.00%,差异有统计学意义(P＜0.05)。MGMT、TopoⅡ基因均在细胞核显示为阳性染色。体外药物干预的实验组、未进行药物干预的阴性对照组干预前U251、U87细胞穿膜细胞计数比较无统计学意义(P＞0.05),但干预后实验组U251、U87细胞穿膜细胞计数高于阴性对照组(P＜0.05),干预后实验组U251、U87细胞有更强的侵袭力。结论 MGMT和TopoⅡ基因在人脑胶质瘤标本中阳性表达率高,且可能参与促进脑胶质瘤细胞侵袭,影响肿瘤化疗敏感性。

Objective To analyze the expression of O6-methylguanine-DNA methyltransferase (MGMT) and DNA topoisomerase II (Topo II) genes in human brain gliomas and its influence on the chemosensitivity. Methods A total of 80 fresh human brain glioma specimens resected by craniotomy and 30 normal brain tissues resected by craniocerebral operation for traumatic brain injury or decompression for cerebral hemorrhage during the period from April 2012 to June 2017 were collected. The expression of MGMT and Topo II genes in the two kinds of specimens was detected by immunohistochemical method, and the influence on chemosensitivity was analyzed through brain glioma U251 and U87 cell culture, in vitro drug (temozolomide) intervention and Transwell invasion in vitro. Results There was a significant difference in the expression of MGMT and Topo II genes in glioma specimens and normal brain tissues (P<0.05). The positive expression rates of MGMT gene in the two kinds of specimens were 63.75% and 3.33% respectively while the positive expression rates of Topo II gene were 55.00% and 0.00%, respectively (P<0.05). Both of MGMT and Topo II genes were displayed in the nucleus as positive staining. There was no significant difference in transmembrane cell count of U251 and U87 cells between the experimental group given drug intervention in vitro and negative control group without drug intervention before the intervention (P>0.05). However, the transmembrane cell count of U251 and U87 cells in the experimental group after intervention was higher than that in the negative control group (P<0.05). After intervetion, U251 and U87 cells were with stronger invasiveness in the experimental group. Conclusion The positive expression rates of MGMT and Topo II genes are high in human brain glioma specimens. They may be involved in promoting glioma cell invasion, affecting tumor chemosensitivity.