Song Joon-Seok
Institute of Biotechnology, Korea University, Seoul 136-701, Korea.
Biosci Biotechnol Biochem. 2004 Aug;68(8):1634-9. doi: 10.1271/bbb.68.1634.
Telomerase is a ribonucleoprotein complex of which the function is to add telomeric repeats to chromosomal ends. Telomerase consists of two essential components, the telomerase RNA template (hTR) and the catalytic subunit (hTERT). hTERT is expressed only in cells and tissues positive for telomerase activity, i.e., tumor and fetal cells. The aim of this study is to test the increased telomerase promoter activity for cancer gene therapy in adenovirus vector. We cloned the hTERT promoter in place of the SV40 promoter in the pGL3-contol vector to be increased by the SV40 enhancer sequences, resulting in strong expression of luc+ only in telomerase positive cancer cells. Then we transfected the constructed plasmid into a normal human cell line and several cancer cell lines. Through these experiments, we identified the selective and increased expression of the luciferase gene controlled by the hTERT promoter and the SV40 enhancer in the telomerase positive cancer cell lines. To investigate the possibility of utilizing the hTERT promoter and the SV40 enhancer in targeted cancer gene therapy, we constructed an adenovirus vector expressing HSV-TK controlled by the hTERT promoter and the SV40 enhancer for the induction of specific telomerase positive cancer cell death. NSCLC cells infected by Ad-hT-TK-enh were more significantly suppressed and induced apoptosis than those infected by Ad-hT-TK. Telomerase is activated in 80 approximately 90% of cancers, so adenovirus with increasing telomerase promoter activity might be used for targeted cancer gene therapy using suicide genes. These results show that the hTERT promoter and the SV40 enhancer might be used for targeted cancer gene therapy.
端粒酶是一种核糖核蛋白复合体，其功能是在染色体末端添加端粒重复序列。端粒酶由两个重要成分组成，即端粒酶RNA模板（hTR）和催化亚基（hTERT）。hTERT仅在端粒酶活性呈阳性的细胞和组织中表达，即肿瘤细胞和胎儿细胞。本研究的目的是测试腺病毒载体中端粒酶启动子活性增强用于癌症基因治疗的效果。我们在pGL3 - 对照载体中克隆hTERT启动子以取代SV40启动子，使其能被SV40增强子序列增强，从而导致荧光素酶（luc +）仅在端粒酶阳性癌细胞中强烈表达。然后我们将构建的质粒转染到一种正常人细胞系和几种癌细胞系中。通过这些实验，我们确定了在端粒酶阳性癌细胞系中，由hTERT启动子和SV40增强子控制的荧光素酶基因的选择性和增强表达。为了研究利用hTERT启动子和SV40增强子进行靶向癌症基因治疗的可能性，我们构建了一种腺病毒载体，其表达由hTERT启动子和SV40增强子控制的单纯疱疹病毒胸苷激酶（HSV - TK），用于诱导特定的端粒酶阳性癌细胞死亡。被Ad - hT - TK - enh感染的非小细胞肺癌（NSCLC）细胞比被Ad - hT - TK感染的细胞受到更显著的抑制并诱导凋亡。大约80%至90%的癌症中端粒酶被激活，因此端粒酶启动子活性增强的腺病毒可能用于使用自杀基因的靶向癌症基因治疗。这些结果表明，hTERT启动子和SV40增强子可能用于靶向癌症基因治疗。
