Telomerase activity in brain tumors.

分析脑肿瘤组织端粒酶活性。采用端粒重复扩增法（TRAP）检测手术切除的41例脑肿瘤、A172例人胶质母细胞瘤细胞和C6例大鼠胶质瘤细胞的端粒酶活性。将41例肿瘤的端粒酶活性与组织学诊断、mb -1增殖细胞指数及患者预后进行比较。以a172胶质母细胞瘤细胞和C6胶质瘤细胞为研究样本，分析了二丁基环AMP、茶碱和视黄酸诱导细胞分化过程中端粒酶活性的变化。研究了乙基亚硝基脲致妊娠大鼠胶质瘤的端粒酶活性。20例胶质母细胞瘤中有12例，2例少突胶质胶质瘤中有2例，3例转移性脑瘤中有3例显示端粒酶活性。而间变性星形细胞瘤、低级别星形细胞瘤和脑膜瘤则无活性。虽然在胶质母细胞瘤中端粒酶活性与mb -1增殖细胞指数之间没有明确的关系，但端粒酶活性倾向于与患者的预后相关。细胞分化后，a172胶质母细胞瘤细胞和C6胶质瘤细胞的端粒酶活性明显降低。乙基亚硝基脲诱导大鼠胶质瘤不同生长阶段的端粒酶活性无差异。这些结果提示端粒酶活性可能是脑肿瘤恶性的重要标志，对其活性的功能性抑制可能在胶质瘤细胞分化过程中发挥作用。

Telomerase activity in brain tumors was analyzed. Telomerase activity was examined in surgically resected 41 brain tumors, A172 human glioblastoma cells, and C6 rat glioma cells by means of telomeric repeat amplification protocol (TRAP) assay. In the 41 tumors, the activity of telomerase was compared with histologic diagnosis, the MIB-1 proliferative cell index and patient's prognosis. In A 172 glioblastoma cells and C6 glioma cells, the changes in the telomerase activity of the cells were analyzed during differentiation induced by dibutyryl cyclic AMP, theophylline and retinoic acid. Telomerase activity in rat gliomas induced by ethylnitrosourea administration in pregnant rats was also examined.Twelve of 20 glioblastomas, 2 of 2 oligodendrogliomas and 3 of 3 metastatic brain tumors demonstrated telomerase activity. However, anaplastic astrocytoma, low grade astrocytoma and meningioma exhibited no activity. Although no clear relations were confirmed in glioblastoma between telomerase activity and the MIB-1 proliferative cell index, the telomerase activity tended to correlate with patient's prognosis. After the cell differentiation, the telomerase activities of A 172 glioblastoma cells and C6 glioma cells were strongly decreased. There were no different telomerase activities among growth stages of rat gliomas induced by ethylnitrosourea.These results suggest that telomerase activity may be an important marker of brain tumor malignancy and that functional inhibition of the activity may play a role during differentiation of glioma cells.