以细胞有丝分裂中纺锤体驱动蛋白为靶点的RNA干扰药物研究

Cancer is a worldwide disease and millions of patients die from cancers every year. A common strategy for cancer therapy is the development of drugs that interrupt the cell cycle during mitosis. A variety of such drugs that bind to tubulin and thus inhibit the spindle assembly are currently used in cancer therapy. But they are non- specific to tumor cells and cause serious neuropathy - associated side effects and multidrug resistance that has hindered their clinical efficacy.. .The mitotic kinesins are new target proteins for cancer therapy. They are a super- family of intra - cellular motor proteins and play vital roles in nearly all stages of cell division. In particular, Eg 5 belongs to a special class of kinesins and it functions exclusively during mitosis. Eg 5 is responsible for the separation of the spindle - pole and the formation of the bipolar mitotic spindle. Inhibition of Eg 5 causes cells to arrest in mitosis with a very characteristic phenotype: cells form a monastrol spindle with an array of microtubules emanating from a pair of non- separated centrosomes. Prolonged mitotic arrest leads to the activation of the mitotic checkpoint and subsequent apoptotic cell death. Also it is highly expressed in tumor cells, so it becomes a novel target for cancer chemotherapy. Since the discovery of monastrol, the first selective inhibitor of kinesin Eg 5, many types of inhibitors have been discovered, but most of them are the small molecules...RNA interference (RNAi), caused by endogenous or exogenous double - stranded RNA( dsRNA or siRNA) with the same source as the target genes, refers to the phenomenon of gene silence widely existing in animals and plants. It was originally found in the bodies of plants, now it has been developed into one of the most promising new approaches for the therapy of many irremediable diseases, especially in cancer chemotherapy. It takes action by hybridizing to mRNA targets by Watson-Crick base pairing and inhibits translation of mRNA in a sequence - specific manner. Due to its high efficiency and specificity, we would like to design, synthesize some new siRNAs that target to the mRNA of mitotic spindle kinesin Eg 5, and test the inhibition activity of them. In addition, we could make some chemical modifications in the siRNAs to improve the enzyme stability and decrease the off - target effect if necessary. It should be a very promising gene therapy strategy in cancer chemotherapy.

纺锤体驱动蛋白(kinesin spindle protein, KSP)是一种对有丝分裂纺锤体的形成起关键作用的驱动蛋白, 人体内的KSP也称为Eg 5，其抑制剂能阻碍细胞周期正常分裂、抑制肿瘤细胞增殖, 是一类新的抗有丝分裂药物。它在增殖细胞中高表达，因此KSP抑制剂具有高特异性和低毒副作用，能避免直接破坏微管的药物所具有的神经毒性。近几年很多KSP抑制剂相继被开发,但主要集中在小分子药物上。.RNA干扰(RNAi)是由双链RNA介导的序列特异性转录后基因沉默过程，其通过双链RNA 分子在mRNA 水平上关闭相关基因的表达。恶性肿瘤是涉及多种基因表达或功能异常的多因素多步骤的病变过程，通过基因手段来治疗恶性肿瘤将是根治癌症的希望。RNAi最主要的特点就在于它能针对特异基因起作用，通过设计合成针对KSP的RNA干扰药物抑制纺锤体驱动蛋白的表达，从而达到抑制肿瘤细胞增殖、治疗癌症的目的。

纺锤体驱动蛋白(kinesin spindle protein，KSP)是一种对有丝分裂纺锤体的形成起关键作用的驱动蛋白，人体内的KSP也称为Eg 5，其抑制剂能阻碍细胞周期正常分裂、抑制肿瘤细胞增殖，是一类新的抗有丝分裂药物。它在增殖细胞中高表达，因此KSP抑制剂具有高特异性和低毒副作用，能避免直接破坏微管的药物所具有的神经毒性。近几年很多KSP抑制剂相继被开发，但主要集中在小分子药物上。.RNA干扰(RNAi)是由双链RNA介导的序列特异性转录后基因沉默过程，其通过双链RNA 分子在mRNA 水平上关闭相关基因的表达。恶性肿瘤是涉及多种基因表达或功能异常的多因素多步骤的病变过程，通过基因手段来治疗恶性肿瘤将是根治癌症的希望。RNAi最主要的特点就在于它能针对特异基因起作用，本项目通过设计合成针对KSP基因的特异性siRNA序列，并对其进行化学修饰，从而获得高活性、高稳定性及低毒副作用的siRNA序列。

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