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常规化疗和放疗受到限制的一个主要因素就是由于非选择性地造成DNA的损伤,而正常组织具有毒性.肿瘤基因治疗的目标是将细胞毒基因转移至肿瘤细胞中,但它最终面临缺乏选择性的问题.目前,有几种可能的方法使基因转导更具选择性.理论上,人们很自然地想到一些病毒载体,由于某些类型的细胞表达或不表达某种病毒的受体,而使它们具有一定程度的选择性.遗憾的是,双向性鼠逆转录病毒受体、腺病毒受体和疱疹病毒受体,在大多数人体细胞中都普遍表达.另外一个办法就是用杂合包被的糖蛋白导向特异的靶细胞受体(例如促红细胞生成素受体).其他的载体正在构建中,它使用不同的被膜(因而具有不同的受体)重组逆转录病毒,而不是在MoMULV中使用的被膜.这样的例子有:根据HIV特异地感染表达CD_4细胞构建的逆转录病毒载体.MoMULV的逆病毒载体具有某些靶向细胞选择性,基于病毒仅整合、表达于分裂活跃的细胞.然而,目前腺病毒、腺相关病毒、疱疹病毒载体,在体内几乎没有选择性.
A major contributing factor to the limitations of conventional chemotherapy and radiotherapy is the non-selective damage caused by DNA, while normal tissues are toxic. The goal of cancer gene therapy is to transfer cytotoxic genes to tumor cells, but it is ultimately lacking in selectivity. The problem. Currently, there are several possible ways to make gene transduction more selective. Theoretically, people naturally think of some viral vectors because certain types of cells express or do not express the receptors of certain viruses. To make them have a certain degree of selectivity. Unfortunately, the bidirectional murine retrovirus receptor, adenovirus receptor and herpes virus receptor are commonly expressed in most human cells. Another approach is to use hybrid packages. Targeted glycoproteins target specific target cell receptors (eg, erythropoietin receptors). Other vectors are under construction. They use different envelopes (and thus different receptors) to assemble recombinant retroviruses instead of MoMULVs. Films used in this case. Examples are: HIV-specific infection of retroviral vectors expressing CD4 cells. The retroviral vector of MoMULV has certain target cell selections. Sex, based on viral integration only, expressed in actively dividing cells. However, adenoviruses, adeno-associated virus, herpes virus vectors in vivo little selectivity.