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卵巢癌是女性生殖器官最常见的恶性肿瘤，尽管目前在其诊断手段和治疗方法上已取得了一定的进展，但其死亡率仍无明显改善，5年生存率始终低于30％，在治疗上尚无突破性进展，因此卵巢癌的治疗已成为妇科肿瘤的难点研究课题。端粒是真核细胞线性染色体末端的蛋白质—DNA结构，保护和稳定染色体的末端，在细胞分裂过程中，端粒重复片断不断丢失，细胞衰老，而大多数肿瘤细胞表达端粒酶来维持端粒长度和阻止细胞衰老，因此，针对端粒酶为靶点的肿瘤基因治疗具有更广阔的应用前景，而通过核酶切割端粒酶RNA以阻断端粒酶表达是可行策略之一。 因此，为了观察端粒酶特异性核酶对卵巢癌细胞生物学特性的影响，进一步探讨其临床应用的可能性，我们进行了如下实验： 1 核酶载体的构建与鉴定 根据端粒酶RNA的cDNA序列，针对其模板区设计了锤头状核酶，并通过基因重组的方法将其定向克隆入载体中，构建核酶体外转录载体及真核表达载体。通过RT-PCR扩增获得端粒酶模板两侧约大小的基因片断，定向克隆入载体后构建成功体 晆;urnu眛tt #h#MNKR#. 眆l#tft~ff*YiiFSfffl~tEU. 2 UB##H~Sflt flRflS1阥t14#h*fl~4t14* town. 6%rflwflflfluc. rnt~fl% finn itU, UBA~iWfl*k68%. 3 fl*PPABURE 110-8910 U*tU jut LipofectAMINH 4#MaSUBZM*ittft#MtUhIOIiiW H0-8910 RNA N*flI&flhtfl. *MtflSltUSt4t MiT #1 WaRM., flR*~*MM*. XtR~*M*U. PiatflURa %MURtbH*fl P0.00. fl BtU*UXI~AFE. *flhIEt. flU RNA*AitflRfl*J#EUPkUI RNA, # ~nwnasrt tM# uWMEtE#aAciautft rm~uttn~ fl-flC**ffITTTSU. 4 Attenuation of Telomerase Activity by a Hammerhead Ribozyme Targeting the Template Region of Abstract Postgraduate Wang Hongying Tutor Xin Xiaoyan Department of Gynecology and Obstetrics The Fourth Military Medical University, Xi’an 710032, China Ovarian cancer is the most common malignant tumor of female reproductive organ, although at present, the diagnosis and treatment methods have progressed in some extent, but the mortality rate hasn’t decreased obviously, the 5-year survival rate is still less than 30%. So, the therapy of ovarian cancer has become a puzzled problem. Telomere is a protein-DNA structure in the end of eukaryotic chromosomes, it can protect and stable the end of chromosome. In all normal somatic cells, each cycle of cell division and DNA replication, the repetitive telomere sequences lose increasingly which leading to cells aging. Telomerase is a ribonucleoprotein polymerase that synthesizes tolemeric DNA onto chromosomal ends using a segment of its RNA moiety as a template. Most maligmant tumor cells express telornerase activity to prevent telomere shortening and contributes to chromosomal stability which is related to immortalization of the cells. Therefore, it has been proposed that anticancer agents based on telomerase inhibition may potentially provide effective therapy. To explore the effects of human telomerase RNA specific 5 hammerhead ribozyme on ovarian carcinoma cell and to further discuss the possibility of clinical application of ribozymes, we conducted the following experiments. 1 Constructions of ribozyme vector: Hammerhead ribozyme directed against template element of the human telomerase RNA component were designe