肿瘤细胞中端粒酶催化亚基hTERT基因启动子结合因子的检测

Identification of telomerase catalytic subunit hTERT gene promoter binding factors in human tumor cells

为了研究端粒酶催化亚基hTERT基因在癌变细胞中组成型表达的调控机制 ,采用凝胶阻滞电泳 (EMSA)实验方法检测人粒系白血病细胞HL 6 0、人红系白血病细胞K5 6 2、人肺癌细胞A5 4 9、人肝癌细胞HepG2及正常人肺成纤维细胞 2BS等体外传代的肿瘤和正常二倍体细胞核提取物中与hTERT启动子核心序列结合的核因子活性。结果在 4种实验肿瘤细胞中均可检测出与hTERT基因启动子结合的核因子活性 ,而正常二倍体细胞中则不存在这种活性的核因子。实验结果提示hTERT基因启动子结合因子可能是细胞癌变过程出现的特殊基因表达调控因子 ,与端粒酶在各种肿瘤细胞中广泛重新激活有关 ,有必要进一步分离鉴定这些肿瘤特异性的转录因子 。

In order to elucidate the reasons for the constitutive expression status of telomerase catalytic subunit hTERT gene in tumor cells, nuclear proteins were extracted from human leukemia cells HL-60,K562,human lung '@''A549,humoma cells HepG2 and human normal diploid cells 2BS,respectiveA549,human hepatcancer cells ity shift assay) was used to detect nuclear factors binding with hTERT gene core promoter region in these cellular nuclear extracts. Results shown that the core promoter region binding nuclear factors were identified in all the tumor cells tested, but not in the normal diploid cells. This finding implied that hTERT gene promoter binding factors may represent a class of tumor specific transcriptional factors playing important roles in tumorigenesis and correspond to the widespread reactivation of telomerase in various tumor cells. It is necessary to isolate and characterize these special transcriptional factors and to clarify their effects on cellular carcinogenesis.