COMPLEMENTARY ADENOVIRAL VECTORS FOR TREATMENT OF CANCER

本提案的主要目标是确定新的复制条件腺病毒载体AdPSAE 1/IL-3的治疗潜力。该载体系统由两种反式互补腺病毒组成，其允许在前列腺和前列腺肿瘤中选择性复制。假设通过在前列腺肿瘤细胞中建立裂解性感染、通过使肿瘤对放射治疗的杀肿瘤作用敏感以及通过增强对内源性肿瘤抗原的免疫应答来产生多模式治疗应答。本提案的目的是以系统的方式检查这些影响，以便随后为患有前列腺癌的患者开发新的治疗方式。溶瘤IL-3病毒载体产物的关键元件是两种腺病毒载体，其彼此互补以允许选择性腺病毒复制和限于癌组织的肿瘤细胞裂解。这些载体之一AdPSAE 1/IL-3的基因组含有用于复制的腺病毒反向末端重复序列（ITR）、腺病毒包装信号、E1基因（其中E1 A在前列腺特异性抗原（pSA）启动子的控制下）和IL-3表达盒。当E1缺失载体也存在时，该载体仅在表达PSA的细胞中繁殖。E1基因的溶瘤作用由AdPSAE 1/IL-3载体感染的细胞中的IL-3表达补充。我们已经证明，IL-3基因治疗使肿瘤对辐射的影响敏感，并刺激能够根除转移性疾病的抗肿瘤免疫应答。IL-3刺激产生全身性抗肿瘤免疫所需的抗原呈递细胞（巨噬细胞和树突细胞）。在动物肿瘤模型中，IL-3细胞因子基因疗法与放射疗法的组合是协同的，导致局部放射疗法的功效增强并产生全身抗肿瘤免疫。拟议的商业应用：我们的互补腺病毒载体系统将首先应用于前列腺癌，尽管我们的目标是将这项技术应用于其他癌症。该载体系统将适用于广泛的癌症，并且将取决于特定肿瘤类型的组织特异性启动子的可用性。正在测试使用通用启动子来驱动溶瘤载体中的E1 A表达，并将使单对互补病毒适用于许多不同的癌症类型。

The major goal of this proposal is to determine the therapeutic potential a new replication conditional adenovirus vector AdPSAE1/IL-3. This vector system is composed of two transcomplementing adenoviruses that permit selective replication in the prostate and prostate tumors. It is hypothesized to engender a multimodal therapeutic response by establishing a lytic infection in prostate tumor cells, by sensitizing the tumor to the tumoricidal effects of radiation therapy and by enhancing the immune response to endogenous tumor antigens. The purpose of this proposal is to examine these effects in a systematic fashion to allow for the subsequent development of a new treatment modality for patients afflicted with prostate cancer. The key elements of the oncolytic IL-3 viral vector product are two adenoviral vectors which complement each other to permit selective adenoviral replication and tumor cell lysis limited to cancer tissues. The genome of one of these vectors, AdPSAE1/IL-3, contains the adenoviral inverted terminal repeats (ITRs) for replication, the adenoviral packaging signal, the E1 genes with E1A under the control of a prostate specific antigen (pSA) promoter, and an IL-3 expression cassette. This vector propagates only in cells that express PSA when an E1-deleted vector is also present. The oncolytic effect of the E1 genes is supplemented by IL-3 expression in cells infected by the AdPSAE1/IL-3 vector. We have demonstrated that IL-3 gene therapy sensitizes tumors to the effects of radiation and stimulates anti-tumor immune responses capable of eradicating metastatic disease. IL-3 stimulates antigen presenting cells (macrophages and dendritic cells) required for the generation of systemic anti-tumor immunity. In animal tumor models, the combination of lL-3 cytokine gene therapy with radiotherapy was synergistic resulting in enhanced efficacy of local radiotherapy and generating systemic anti-tumor immunity. PROPOSED COMMERCIAL APPLICATIONS: Our complementary adenoviral vector system will be initially applied to prostate cancer, although our goal is to apply this technology to other cancers as well. The vector system will be applicable to a broad range of cancers and will depend on the availability of tissue specific promoters for the particular tumor type. The use of a general promoter to drive E1A expression in the oncolytic vector is being tested and will make a single pair of complementary viruses applicable to many different cancer types.