Cancer dual-targeting of an infectivity-enhance CRAd

描述（由申请人提供）：对肿瘤转化和进展的分子机制的研究已使人们认识到癌症是一种遗传性疾病，源于一系列获得性遗传病变的积累。尽管化疗、放疗和手术治疗方案取得了进展，但许多晚期癌症的生存率仍然很低，显然替代治疗方法是必要的。基因治疗/病毒治疗是治疗癌症的一种有前途的策略。尽管过去曾尝试过，但由于毒性和无效而被放弃，病毒治疗方法已重新出现，并具有很大的前景，这在很大程度上是由于对病毒生物学的更好理解和对病毒进行遗传修饰的能力。有了这些知识，我们现在可以设计病毒来更好地复制并特异性地杀死肿瘤细胞。使用条件复制型腺病毒（CRAd）代表了实现有效的肿瘤细胞溶瘤和减轻肿瘤细胞感染限制的方法。理想地，CRAd的癌症特异性复制将导致病毒介导的感染肿瘤组织的溶瘤作用和病毒子代的释放，所述病毒子代能够在周围肿瘤细胞中而不是在正常组织的那些细胞中进一步增殖，所述正常组织的那些细胞对于CRAd复制是难治的。在我们的I期研究中，我们开发了一种新的癌症特异性mRNA翻译起始控制，以实现CRAd病毒治疗剂的增强的复制特异性。相反，迄今为止，mRNA翻译的控制尚未被用于设计肿瘤特异性复制病毒。这种方法结合了转录和翻译调控策略，以实现CRAd复制特异性的关键目标，其技术和科学价值以及可行性现已确立。我们的I期体外和体内研究证明了强有力的原理证明，该CRAd试剂利用异源mRNA翻译控制元件保留了抗肿瘤效力。该II期申请的目的是通过优化具有增强的肿瘤感染性的CRAd病毒治疗剂来继续在I期开始的研发工作。在许多体内基因治疗试验中已经注意到肿瘤组织对腺病毒血清型5（Ad 5）感染的相对抗性。初级Ad受体CAR的缺陷被理解为这种现象的生物学基础。已显示将高亲和力Arg-Gly-Asp（RGD）基序包含到Ad 5纤维球的H1环中克服了肿瘤细胞上的低CAR表达，从而增强转导。在特定目标1中，CRAd病毒治疗剂的癌细胞转导将通过插入RGD基序而增强。在具体目标2中，将进行体内实验，以评估生物学疗效，并在局部和播散性疾病的动物模型中建立具体的治疗方案。最后，在具体目标3中，将进行向FDA提交IND所需的生物分布和毒理学研究。该II期申请的成功完成将直接导致在患有播散性疾病的患者中对修饰的CRAd试剂（CXCR 4 - 5 '-UTR-RGD CRAd）的临床研究。公共卫生相关性：尽管标准治疗方案取得了许多进展，但许多晚期癌症的生存率仍然很低，很明显，新的替代治疗方法是必要的。使用设计用于分裂并特异性杀死肿瘤细胞的病毒已成为更好地理解病毒生物学和遗传修饰病毒能力的有希望的方法。本申请的目的是进一步开发一种条件复制型腺病毒（CRAd），该腺病毒被设计为在肿瘤细胞中有效感染、分裂和裂解，但在正常细胞中无效;成功完成。

DESCRIPTION (provided by applicant): Studies of the molecular mechanisms underlying neoplastic transformation and progression have resulted in the understanding that cancer is a genetic disease, deriving from the accumulation of a series of acquired genetic lesions. Despite advances in chemotherapy, radiation delivery, and surgical treatment regimens, survival from many advanced cancers remains poor, and it is apparent that alternative treatment approaches are necessary. Gene therapy/virotherapy is a promising strategy for the treatment of cancer. Although attempted in the past and abandoned because of toxicity and inefficacy, the virotherapy approach has reemerged with great promise, in large part due to better understanding of virus biology and the ability to genetically modify viruses. With this knowledge, we can now design viruses to better replicate in and specifically kill tumor cells. Using conditionally replicative adenoviruses (CRAds) represent a method to achieve efficient tumor cell oncolysis and mitigate tumor cell infection limitations. Ideally, cancer-specific replication of CRAds would result in viral-mediated oncolysis of infected tumor tissues and release of the virus progeny, capable of further propagating in surrounding tumor cells but not in those of normal tissues, which would be refractory to CRAd replication. In our Phase I study, we exploited a novel cancer-specific control of mRNA translation initiation in order to achieve enhanced replicative specificity of a CRAd virotherapy agent. In contrast, control of mRNA translation has not been exploited for the design of tumor specific replicating viruses to date. The technical and scientific merit and feasibility of this approach that combines both transcriptional and translational regulation strategies for the key goal of CRAd replicative specificity has now been established. Our Phase I in vitro and in vivo studies demonstrated strong proof-of-principle that this CRAd agent, utilizing a heterologous mRNA translational control element, retains anti-tumor potency. The objective of this Phase II application is to continue the R&D efforts initiated in Phase I by optimizing the CRAd virotherapy agent with enhanced tumor infectivity. Relative resistance of tumor tissues to adenovirus serotype 5 (Ad5) infections has been noted in a number of in vivo gene therapy trials. Deficiency of the primary Ad receptor CAR, is understood to be the biologic basis of this phenomenon. The inclusion of a high affinity Arg-Gly-Asp (RGD) motif into the HI loop of the Ad5 fiber knob has been shown to overcome low CAR expression on tumor cells, thereby enhancing transduction. In Specific Aim 1, cancer cell transduction of the CRAd virotherapy agent will be enhanced by inserting an RGD motif. In Specific Aim 2, in vivo experiments will be conducted to evaluate the biological efficacy and establish specific treatment protocols in animal models of loco-regional and disseminated disease. Finally, in Specific Aim 3, biodistribution and toxicology studies required for IND submission to the FDA will be performed. Successful completion of this Phase II application will lead directly to clinical investigation of the modified CRAd agent (CXCR4-5'-UTR-RGD CRAd) in patients with disseminated disease. PUBLIC HEALTH RELEVANCE: Despite many advances in standard treatment regimens, survival from many advanced cancers remains poor, and it is apparent that new alternative treatment approaches are necessary. Using viruses designed to divide in and specifically kill tumor cells has become a promising approach to better understanding of virus biology and the ability to genetically modify viruses. The objective of this application is to further develop a conditionally replicative adenovirus (CRAd) that has been designed to infect, divide and lyse efficiently in tumor cells but not in normal cells; successful completion.