Basic studies for telomerase as a novel target for cancer diganosis and therapy

研究人员测量了130例乳腺癌、70例胃癌、94例结肠癌和43例胰腺癌患者的端粒长度和端粒酶活性。采用Southern blot法测定肿瘤标本端粒（末端限制性片段）长度。端粒长度减少和延长的比例分别为27%和8%。端粒重复扩增法（TRAP）测定端粒酶活性。在非癌组织中，端粒酶活性在胃和结肠粘膜标本中检测到。对这些标本表面的连续切片进行TRAP检测显示，在肠隐窝细胞（肠干细胞）存在的部分可检测到端粒酶活性。在癌症组织中，95%的乳腺癌、85%的胃癌、73%的结肠癌和96%的胰腺癌中检测到端粒酶激活或上调。使用35个PCR循环和密度分析的非同位素TRAP方法显示出与常规TRAP方法相同的灵敏度，表明非同位素TRAP方法可用于临床检查。在冷冻切片中尝试使用原位PCR进行TRAP检测。在肿瘤腹膜播散细胞和胰腺刷壁细胞中，端粒酶表达细胞和非表达细胞共存，端粒酶表达可能与细胞周期相关。在82例乳腺肿瘤细针抽吸细胞样本和38例胃或结肠内镜涂片样本中，83%的恶性肿瘤样本端粒酶活性可检测到。因此，端粒酶活性对癌细胞存在的诊断是有用的。然而，端粒酶的激活或上调并不总是存在于所有癌细胞中，而是可能根据癌症的进展而获得。因此，使用端粒酶抑制剂的抗癌治疗被认为对晚期癌症是有用的。然而，正常粘膜和造血干细胞的副作用需要引起足够的注意。少

Telomere length and telomerase activity were measured in 130 breast cancers, 70 gastric cancers, 94 colonic cancers and 43 pancreatic cancers. Telomere (terminal restriction fragments) lengths of these tumor specimens were measured by Southern blot analysis. Reduced and elongated telomere lengths were detected in 27% and 8%, respectively. Telomerase activity was measured using Telomeric Repeat Amplification Protocol (TRAP) assay. Among noncancerous tissues, telomerase activity was detectable in gastric and colonic mucosal specimens. TRAP assay for serial sections from the surface of these specimens revealed telomerase activity was detectable in the portions where intestinal crypt cells (intestinal stem cells) exist. Among cancer tissues, telomerase activation or upregulation was detected in 95% of breast cancres, 85% of gastric cancers, 73% of colonic cancers, 96% of pancreatic cancers. Non-isotopic TRAP assay using of 35 PCR cycles and densitographic analysis showed the same sensitivi … More ty as usual TRAP assay, indicating the non-isotopic TRAP assay is useful for clinical examination. TRAP assay using of in situ PCR was tried to measure in cryosections. In peritoneal disseminated cells and pancreatic brushing cells of cancer, telomerase expressing cells and non-expressing cells coexisted and telomerase expression was likely to be correlated with cell cycles. In 82 samples of fine needle aspirated cells of breast tumors and 38 smear samples obtained by gastric or colonic endoscopy, 83% of the samples diagnosed as malignancy showed detectable telomerase activity. Thus, telomerase activity was useful for the diagnosis of cancer cell existence. However, telomerase activation or upregulation does not always exist in all cancer cells but is likely to be acquired according to cancer progression. Thus, anticancer therapy using of inhibitors of telomerase is considered to be useful for advanced cancers. However, canful attentions are required for the side effects of normal mucosal and hematopoietic stem cells. Less