Tumor Sensitization to Purine Analogs by E. coli PNP

描述（由申请人提供）：本实验室计划描述了E。coli PNP基因在体内外杀伤人癌细胞的研究。这将包括临床批准的前药（F-araAMP）介导旁观者杀伤的表征，以及在动物模型中的安全性和有效性研究。我们计划开发用于PNP递送的载体策略，并提高我们对酶促化学增敏的理解。这一信息，连同新的分子工具（单克隆和多克隆抗体抗大肠杆菌。coli PNP;纯化的PNP蛋白）构成了本申请的三个具体目的的基础，如下所述：具体目的I：提高E. coli PNP前体药物并检查作用机制。我们将探索旁观者杀伤的阈值，克服毒性的方法，以及体内策略所赋予的活性谱。具体目标II：开发临床上有用的载体系统，用于递送E。coli PNP对肿瘤的抑制作用。我们将：i）改进γ 1 34.5缺失的疱疹病毒载体，特别是用于E。大肠杆菌PNP和ii）改进了最近的数据，表明用腺病毒编码大肠杆菌PNP的抗肿瘤活性。coli PNP的活性和肿瘤内分布。具体目标三：消灭E.大肠杆菌PNP策略的体内试验和在胶质瘤、结肠和头颈肿瘤的鼠模型中的活性和安全性的测试谱。这些实验旨在使用有效的旁观者杀伤机制证明体内肿瘤消退和治愈，建立该策略的广谱活性，并为在人类受试者体内测试相同方法提供基础。

DESCRIPTION (provided by applicant): This Laboratory Program describes use of the E. coli PNP gene for destroying human cancer cells in vitro and in vivo. This will include characterization of a clinically approved prodrug (F-araAMP) that mediates bystander killing, and studies of both safety and efficacy in animal models. We plan to develop vectoring strategies for delivery of PNP, and improve our understanding of enzymatic chemosensitization. This information, together with new molecular tools (monoclonal and polyclonal antibodies against E. coli PNP; purified PNP protein) form the foundation of the three Specific Aims in this application, as described below: Specific Aim I: Improve the therapeutic usefulness of E. coli PNP prodrugs and examine mechanism of action. We will explore thresholds for bystander killing, ways to overcome toxicity, and spectrum of activity conferred by the strategy in vivo. Specific Aim II: Develop clinically useful vector systems for delivering E. coli PNP to tumors in vivo. We will: i) refine gamma1 34.5 deleted herpes viral vectors specifically for use with E. coli PNP and ii) improve upon recent data indicating anti-tumor activity with adenovirus encoding E. coli PNP by augmenting activity and intra-tumoral distribution. Specific Aim III: Validate the E. coli PNP strategy in vivo and test spectrum of activity and safety in murine models of glioma, colon, and head/neck tumors. These experiments are intended to demonstrate tumor regressions and cures in vivo using a potent bystander killing mechanism, establish broad spectrum of activity for the strategy, and provide a foundation for testing the same approach in human subjects in vivo.