Liu Bailin, Qu Yi, Liu Shuqiu, Ouyang Xuesong
Laboratory of Medical Molecular Biology, West China University of Medical Sciences, 610041, Chengdu, China,
Sci China C Life Sci. 2002 Feb;45(1):87-95. doi: 10.1360/02yc9010.
Telomerase plays an important role in cell proliferation and carcinogenesis and is believed to be a good target for anti-cancer drugs. Elimination of template function of telomerase RNA may repress the telomerase activity. A hammer-headed ribozyme (telomerase ribozyme, teloRZ) directed against the RNA component of human telomerase (hTR) was designed and synthesized. TeloRZ showed a specific cleavage activity against the hTR. The cleavage efficacy reached 60%. A eukaryotic expression plasmid containing teloRZ gene was inducted into HeLa cells by lipofectamine, the telomerase activity in HeLa cells expressing teloRZ decreased to one eighth of that in the control cells. The doubling time increased significantly and the apoptosis ratio was elevated with increasing population doublings (PDS). After 19-20 PDS 95% cells were apoptotic. To further investigate the effect of teloRZ on tumor growth, the eukaryotic expression plasmid containing teloRZ was injected into transplanted tumor of nude mouse. The teloRZ effectively inhibited the telomerase activity in transplanted tumor, promoted apoptosis of the transplanted tumor cells, and decreased the tumor size significantly. These results indicate that teloRZ can effectively inhibit telomerase activity and growth of tumor cells, and suggest the potential use of this ribozyme in anti-cancer therapy.
端粒酶在细胞增殖和致癌过程中发挥着重要作用，被认为是抗癌药物的良好靶点。消除端粒酶RNA的模板功能可能会抑制端粒酶活性。设计并合成了一种针对人端粒酶RNA成分（hTR）的锤头状核酶（端粒酶核酶，teloRZ）。teloRZ对hTR表现出特异性切割活性。切割效率达到60%。通过脂质体转染将含有teloRZ基因的真核表达质粒导入HeLa细胞，表达teloRZ的HeLa细胞中的端粒酶活性降至对照细胞的八分之一。随着群体倍增次数（PDS）增加，倍增时间显著延长，凋亡率升高。在19 - 20次PDS后，95%的细胞发生凋亡。为了进一步研究teloRZ对肿瘤生长的影响，将含有teloRZ的真核表达质粒注射到裸鼠移植瘤中。teloRZ有效抑制了移植瘤中的端粒酶活性，促进了移植瘤细胞的凋亡，并显著减小了肿瘤大小。这些结果表明，teloRZ能有效抑制肿瘤细胞的端粒酶活性和生长，并提示这种核酶在抗癌治疗中的潜在应用价值。
