脱氧核酶对鼻咽癌细胞端粒酶活性的抑制作用  

Inhibition of Telomerase Activity in Nasopharyngeal Carcinoma Cell Line by Two Synthesized DNAzymes Targeting against Telomerase RNA Component

作　　者：赵家明[1] 李明意[2] 杨展[1] 吴柱国[1] 李震[1] 张毅[1] 

机构地区：[1]广东医学院附属医院中心实验室,湛江524001 [2]广东医学院附属医院普通外科,湛江524001

出　　处：《华中科技大学学报（医学版）》2005年第3期330-333,共4页Acta Medicinae Universitatis Scientiae et Technologiae Huazhong

基　　金：广东省卫生厅青年基金资助项目(No.B1997119)

摘　　要：目的探讨脱氧核酶对端粒酶RNA组分的切割作用及对鼻咽癌端粒酶活性的抑制作用。方法针对端粒酶RNA组分(hTR)的核苷酸序列,合成“10～23”型脱氧核酶及其类似物,提取总RNA在体外切割hTRmRNA;转染鼻咽癌细胞后,用RTPCR扩增hTR基因片段,用PCRELISA法测定端粒酶活性。结果未经修饰的脱氧核酶DzT和在DzT的3′末端添加倒位连接T碱基的脱氧核酶DzTi在体外能够有效地切割hTRmRNA;在转染鼻咽癌细胞后,DzTi比DzT对hTRmRNA表现出更强的切割作用,DzTi能够显著地降低鼻咽癌细胞端粒酶活性(P<0.01);但DzTi和DzT转染对鼻咽癌细胞的生长均没有明显的影响(P>0.05)。DzT和DzTi的催化中心的一个碱基被替换后形成的脱氧寡核苷酸DzT’和DzTi’在胞外和胞内均不表现对hTRmRNA的切割作用。结论人工合成的脱氧核酶能够高效特异地切割端粒酶RNA组分,并降低鼻咽癌细胞的端粒酶活性。作为一种新发现的催化性核酸,脱氧核酶在肿瘤的基因治疗领域中将具有极其重要的应用价值。Objective To explore the cleavation of telomerase RNA component (hTR) and the inhibition of telomerase activity by DNAzymes in a human nasopharyngeal carcinoma cell line (CNE-2Z).Methods Two “10~23” DNAzymes (DzT and DzTi) targeted against hTR mRNA and their analogues (DzT’and DzTi’) were synthesized and used to cleave hTR mRNA in vitro and in CNE-2Z cells. The RT-PCR amplification of an hTR DNA fragment and telomerase activity assay by PCR-ELISA were performed to assess the cleaving efficiency.Results The unmodified DNAzyme, DzT, and its modified form, DzTi, which had an added 3'-inverted thymidine, could effectively cleave hTR mRNA in vitro. After transfection into CNE-2Z cells, DzTi exhibited more powerful cleaving ability than DzT, and down-regulated the telomerase activity of the cells significantly (P<0.01). However, neither DzTi nor DzT displayed obvious influence on the growth of the cells (P>0.05). DzT’and DzTi’, which derived respectively from DzT and DzTi with a base displacement in the conserved catalytic motif, did not exhibit notable cleaving effect on hTR mRNA either in vitro or in cells.Conclusion The synthesized DNAzymes could cleave the telomerase RNA component with effectiveness and specificity, and decrease the telomerase activity of CNE-2Z. As a newly found catalytic nucleic acid, DNAzymes will play an important role in the antitumor field.

关 键 词：催化性DNA 端粒酶 鼻咽肿瘤 

分 类 号：R739.6[医药卫生—肿瘤] Q523[医药卫生—临床医学]