Shen Ying, Zhang Yong-Wei, Zhang Zhi-Xiang, Miao Ze-Hong, Ding Jian
Division of Anti-Tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
Cancer Biol Ther. 2008 Feb;7(2):228-36. doi: 10.4161/cbt.7.2.5259. Epub 2007 Nov 3.
Telomerase is proposed as an anticancer target. Increasing evidence suggests that telomerase is involved in functions independent of telomere-extension activity. In this study, we designed a small interfering RNA (siRNA) targeting human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase. Using transient and persistent transfection of hTERT siRNA into telomerase-positive human colon carcinoma HCT116 cells, we demonstrated that hTERT siRNA suppresses hTERT expression and leads to inhibition of telomerase activity and HCT116 cell growth and in vivo tumorigenicity in nude mice. Further analysis indicated that depletion of hTERT reduces cell adhesion, migration, and invasion prior to inhibition of cell proliferation. Downregulation of hTERT also decreased the expression levels of adhesion- and motility-related proteins, in particular c-Met and integrins. The lack of detectable changes in telomere length showed that downregulation of hTERT in the present system had no significant effect on telomere-extension activity. Taken together, our results highlight the therapeutic potential of a novel hTERT siRNA and suggest that hTERT is involved in the regulation of cell motility in a telomere-independent manner.
端粒酶被认为是一个抗癌靶点。越来越多的证据表明，端粒酶参与了独立于端粒延伸活性的功能。在本研究中，我们设计了一种靶向人端粒酶逆转录酶（hTERT）的小干扰RNA（siRNA），hTERT是端粒酶的催化亚基。通过将hTERT siRNA瞬时和持续转染到端粒酶阳性的人结肠癌HCT116细胞中，我们证明hTERT siRNA抑制hTERT表达，并导致端粒酶活性、HCT116细胞生长以及裸鼠体内肿瘤发生能力受到抑制。进一步分析表明，在抑制细胞增殖之前，hTERT的缺失会降低细胞黏附、迁移和侵袭能力。hTERT的下调还降低了黏附及运动相关蛋白的表达水平，尤其是c-Met和整合素。端粒长度未检测到明显变化表明，本系统中hTERT的下调对端粒延伸活性没有显著影响。综上所述，我们的结果突出了一种新型hTERT siRNA的治疗潜力，并表明hTERT以一种不依赖端粒的方式参与细胞运动的调控。
