SV40大T抗原在人脑肿瘤中与p53形成特异性复合物

目的 探讨SV40早期区域基因编码产物大T抗原（Tag) 表达及与抑癌蛋白p53的相互作用在人脑肿瘤发生发展中的意义。方法 采用免疫共沉淀及Western印迹法检测43例人脑肿瘤组织及5例正常人脑组织中Tag的表达,并对18例Tag阳性瘤组织检测Tag-p53复合物的存在。结果 Tag在5例室管膜瘤及2例脉络丛乳头状瘤中全部表达,垂体腺瘤（5／6）、星形胶质细胞瘤（7／10）、脑膜瘤（4／6）、多形性胶质母细胞瘤（3／5）及髓母细胞瘤（2／5）均有Tag的表达,3例少枝胶质细胞瘤、1例松果体瘤及5例正常人脑组织无Tag表达;检测18例Tag阳性瘤组织均发现Tag与p53形成特异性复合物。结论 在人脑肿瘤组织中Tag广泛表达,Tag可与p53形成特异性复合物,Tag-p53特异性复合物的形成导致p53失活,可能是SV40致人脑肿瘤发生的一个重要机理。

Formation of specific complex of SV40 large tumor antigen and p53 in human brain tumors

Objective To study the interaction of SV40 early region gene coding product, the large tumor antigen (Tag) with tumor suppressor p53 in human brain tumorigenesis. Methods Tag was detected by immunoprecipitation and Western blot in 43 cases of human brain tumors and 5 cases of normal human brain tissues. Tag|p53 specific complex was screened in 18 Tag positive cases. Results Tag was found in all of 5 ependymomas and 2 choroid plexus papillomas, as well as in pituitary adenomas (5/6),astrocytomas (7/10), meningiomas (4/6), glioblastomas multiforme (3/5) and medulloblastomas (2/5). None of the 5 normal brain tissues were positive for Tag, nor were 3 oligodendrogliomas and 1 pineocytoma. Tag|p53 complexs were found in all of 18 Tag positive cases. Conclusion SV40 Tag can form a specific complex with p53 in human brain tumors, the inactivation of p53 due to the formation of Tag|p53 complex may be one of the important mechanisms of human brain tumorigenesis.