Yokoyama Y, Takahashi Y, Shinohara A, Lian Z, Wan X, Niwa K, Tamaya T
Department of Obstetrics and Gynecology, Gifu University School of Medicine, Gifu, Japan.
Cancer Res. 1998 Dec 1;58(23):5406-10.
Telomerase activity is found in almost all carcinoma cells but not in most somatic cells, suggesting that telomerase is an excellent target for cancer therapy. We designed hammerhead ribozymes against human telomerase RNA and studied their possible use as a tool for cancer therapy. Three ribozymes targeting the 3' end of the GUC sequence at 33-35 (the template region), 168-170, and 313-315 from the 5' end of telomerase RNA were designed. In a cell-free system, these three hammerhead ribozymes efficiently cleaved the RNA substrate. When these ribozyme RNAs were introduced into Ishikawa cells, which are endometrial carcinoma cells, only a ribozyme targeting the RNA template region could diminish the telomerase activity. Next we subcloned the ribozyme sequence into an expression vector and introduced this into AN3CA cells, which are endometrial carcinoma cells. The clones that were obtained showed reduced telomerase activity and telomerase RNA with expression of the ribozyme. These data suggest that the ribozyme against the RNA template region is a good tool to repress telomerase activity in cancer cells.
端粒酶活性几乎在所有癌细胞中都能检测到，而在大多数体细胞中则未检测到，这表明端粒酶是癌症治疗的一个理想靶点。我们设计了针对人端粒酶RNA的锤头状核酶，并研究了它们作为癌症治疗工具的潜在用途。设计了三种核酶，分别靶向端粒酶RNA 5'端第33 - 35位（模板区域）、168 - 170位以及313 - 315位的GUC序列的3'端。在无细胞体系中，这三种锤头状核酶能高效切割RNA底物。当将这些核酶RNA导入子宫内膜癌细胞系Ishikawa细胞时，只有靶向RNA模板区域的核酶能够降低端粒酶活性。接下来，我们将核酶序列亚克隆到表达载体中，并将其导入子宫内膜癌细胞系AN3CA细胞。获得的克隆显示，随着核酶表达，端粒酶活性和端粒酶RNA水平降低。这些数据表明针对RNA模板区域的核酶是抑制癌细胞中端粒酶活性的良好工具。
