Second Generation Adenoviral Vectors for Cancer Therapy

我们的研究计划已经开发出一种新的，三模式的基因治疗为基础的方法来治疗癌症。我们的方法利用溶细胞的、具有复制能力的腺病毒（Ad 5-CD/TKrep）选择性地和有效地将一对治疗性“自杀”基因递送至肿瘤。我们的临床前研究已经证明，Ad 5-CD/TKrep病毒本身，通过其细胞溶解活性，具有有效的抗肿瘤活性。Ad 5-CD/TKrep病毒疗法的功效可通过调用两个自杀基因系统（CD/5-FC和HSV-1 TK/GCV）而显著增强，这使得恶性细胞对特定药理学试剂敏感，并且重要的是，使它们对辐射敏感。项目1的主要目标是开发第二代腺病毒，其可能比亲本Ad 5-CD/TKrep病毒更有效且毒性更低。我们将确定是否第二代腺病毒含有各种E3基因表现出更大的抗肿瘤活性，在免疫活性的主机相对于父母Ad 5-CD/TKrep病毒。我们将检验E3基因抑制宿主免疫反应将导致长期治疗性基因表达和改善肿瘤控制的假设。抗肿瘤活性将与体内治疗性基因表达的持续时间以及免疫应答的程度和性质相关。我们将确定表达更有催化活性的酵母CD/突变型HSV-1 TK（SR 39）转基因的第二代腺病毒是否比亲本Ad 5-CD/TKrep病毒产生更好的肿瘤控制。我们将研究第二代腺病毒在免疫活性小鼠前列腺内和静脉内给药后的毒性。最后，我们将开发一系列的第二代腺病毒表达人钠碘同向转运体（hNIS）。我们将测试的假设，hNIS的表达将使病毒感染的细胞采取（99 m）TcO 4-和（123）I，并允许非侵入性监测载体的生物分布和治疗基因的表达在体内。项目1中开发的所有第二代腺病毒将用于本计划的其他项目。

Our research program has developed a novel, trimodal gene therapy-based approach for the treatment of cancer. Our approach utilizes a cytolytic, replication-competent adenovirus (Ad5-CD/TKrep) to selectively and efficiently deliver a pair of therapeutic "suicide" genes to tumors. Our preclinical studies have demonstrated that the Ad5-CD/TKrep virus itself, via its cytolytic activity, has potent anti-tumor activity. The efficacy of Ad5-CD/TKrep viral therapy can be enhanced significantly by invoking two suicide gene systems (CD/5-FC and HSV-1 TK/GCV), which render malignant cells sensitive to specific pharmacological agents and importantly, sensitizes them to radiation. A major objective of Project 1 is to develop second-generation adenoviruses that may be more efficacious and less toxic than the parental Ad5-CD/TKrep virus. We will determine whether second-generation adenoviruses containing various E3 genes demonstrate greater anti-tumor activity in an immune-competent host relative to the parental Ad5-CD/TKrep virus. We will test the hypothesis that suppression of the host immune response by E3 genes will result in longer-term therapeutic gene expression and improved tumor control. Anti-tumor activity will be correlated with the duration of therapeutic gene expression in vivo and the extent, and nature, of the immune response. We will determine whether second-generation adenoviruses expressing a more catalytically active yeast CD/mutant HSV-1 TK(SR39) transgene results in better tumor control than the parental Ad5-CD/TKrep virus. We will examine the toxicity of second-generation adenoviruses in the immune-competent mouse following intraprostatic and intravenous administration. Finally, we will develop a series of second-generation adenoviruses expressing the human sodium iodide symporter (hNIS). We will test the hypothesis that expression of hNIS will enable virus-infected cells to take up (99m)TcO4- and (123)I and allowing for non-invasive monitoring of vector biodistribution and therapeutic gene expression in vivo. All of the second-generation adenoviruses developed in Project 1 will be used in the other projects of this Program.