MULTIPLE GENE CARRIER ADENOVIRAL CONSTRUCTS FOR GLIOMAS

恶性脑胶质瘤对目前采用的手术、放疗和化疗联合治疗具有很高的耐药性。与传统的治疗形式相反，特异性肿瘤抑制基因和凋亡基因的替代是一种针对基本肿瘤机制的治疗。恶性胶质瘤是一种多基因改变的疾病。因此，有效的治疗应该包括基因组合而不是单基因替代。一个有效的基因组合应该在细胞增殖的几个点上诱导抑制，并激活程序性细胞死亡的各种途径。治疗基因的递送可以通过使用腺病毒作为载体来实现。本项目的第一个目标是设计和构建重组腺病毒载体，携带多种肿瘤抑制基因（Ad5-MSG），或凋亡介导基因（Ad5-APG），或两者的组合（Ad5-SAPG）。重组腺病毒将在检测携带单一肿瘤抑制基因（p16、p53、Rb）或凋亡基因（p53、E2F1、ICE、反义bel-2）的腺病毒的各种组合对胶质瘤细胞生长和凋亡的潜在加性或协同效应后构建。随后，这些构建体的生物活性和抗癌机制分析将在各种胶质瘤细胞系中进行测试。第二个目标是在动物模型中评估这种联合基因方法的体内功效、抑制致瘤性和毒性。第三个目标是研究外源基因之间的相互作用及其与其他参与肿瘤发生、肿瘤生长、血管生成、程序性细胞死亡和肿瘤侵袭调控的分子的关系。本研究提出了一种基于基因组合的抗癌策略，通过不同的生长抑制和细胞死亡机制产生细胞抑制和细胞毒性作用。

Malignant cerebral gliomas are highly resistant to the currently employed treatment with combination of surgery, radiotherapy and chemotherapy. As opposed to conventional forms of therapy, the replacement of specific tumor suppressor and apoptotic genes is a treatment directed against the basic neoplastic mechanism. Malignant glioma represents a multiple-gene alterations disease. Thus, effective therapy should involve gene combinations rather than single-gene replacement. An efficient combination of genes should induce inhibition at several points of cell proliferation and activate the various pathways of programmed cell death. The delivery of the therapeutic genes can be attained by using adenoviruses as carrier vehicles. The first aim of this project is to design and construct recombinant adenoviral vectors, carrying either multiple tumor suppressor genes (Ad5-MSG), or apoptosis-mediating genes (Ad5-APG), or combination of both (Ad5-SAPG). The recombinant adenoviruses will be constructed after testing of the potential additive or synergistic effect of various combinations of adenoviruses carrying single tumor suppressor (p16, p53, Rb), or apoptotic genes (p53, E2F1, ICE, antisense bel-2), on growth and apoptosis of glioma cells. Subsequently, the biologic activity and analysis of the anti-cancer mechanisms of these constructs will be tested in a variety of glioma cell lines. The second aim will assess the in vivo efficacy, inhibition of tumorigenicity and toxicity of this combination gene approach in an animal model. The third aim will investigate the interactions among the exogenous genes and their relationship with other molecules involved in the regulation of tumorigenesis, tumor growth, angiogenesis, programmed cell death, and tumor invasion. This study presents an anti-cancer strategy based on gene combinations to generate cytostatic and cytotoxic actions through distinct growth inhibitory and cell death mechanisms.