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利用E.ColiPNP基因在体外和体内摧毁人类癌细胞。这将包括临床批准的前药(F-araAMP)的特性，以及在动物模型中对安全性和有效性的研究。我们计划开发传递PNP的载体策略，并提高我们对酶化学增敏的理解。这些信息与新的分子工具(针对E.ColiPNP的单抗和多克隆抗体；纯化的PNP蛋白)一起构成了本申请的三个特定目的的基础，如下所述：特定目的I：提高E.ColiPNP前药的治疗有效性并研究其作用机制。我们将探索旁观者杀戮的阈值，克服毒性的方法，以及该策略在体内赋予的活动光谱。特定目的II：开发临床有用的载体系统，用于将大肠杆菌PNP运送到体内的肿瘤中。我们将：i)提炼专门用于大肠杆菌PNP的Gamma1 34.5缺失疱疹病毒载体，以及ii)通过增强活性和肿瘤内分布来改进编码E.coliPNP的腺病毒的抗肿瘤活性的最新数据。具体目的III：在体内验证E.Coli PNP策略，并在小鼠胶质瘤、结肠和头颈部肿瘤模型中测试活性和安全性。这些实验旨在利用一种有效的旁观者杀伤机制在体内展示肿瘤的退化和治愈，为该策略建立广泛的活性，并为在体内测试相同的方法提供基础。

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.