端粒、端粒酶和肿瘤治疗

TELOMERES, TELOMERASE AND CANCER THERAPY

线性染色体的末端是由重复序列ＴＴＡＧＧＧ组成，称为端粒，由于ＤＮＡ的不完全复制正常体细胞随着细胞分裂的进行而逐渐丢失端粒序列。肿瘤细胞通过表达端粒酶———一种ＲＮＡ依赖性ＤＮＡ聚合酶而补偿端粒序列的丢失，从而保持端粒的长度。近９０％的人类肿瘤可检测到端粒酶活性，而正常体细胞缺乏这种酶的活性。本文综述了端粒，端粒酶的功能及其与肿瘤的相关性，论及了端粒酶作为肿瘤诊断的标志及肿瘤治疗的新靶点。

The ends of linear chromosomes are composed of a repeated sequence,TTAGGG,which are known as telomeres. Normal somatic cells progressivelly lose telomeric repeats with each successive cell division due to DNA incomplete replication.Cancer cells compensate for telomeric loss by expressing the enzyme telomerase,an RNA-dependent DNA polymerase that maintains telomere length.Telomerase activity has been detected in almost 90%of all human cancers,but is generally absent in normal somatic cells.This review summarized structure and function of telomere and telomerase and their relation to cancer,as well as the potential value of telomerase as a diagnostic marker and a new therapeutic target for cancer.