Cancer dual-targeting of an infectivity-enchanced CRAd

感染性增强的 CRAd 的癌症双重靶向

• 批准号: 7053481
• 负责人: J. Michael Mathis
• 金额: $ 10万
• 依托单位: VECTORLOGICS, INC.
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7053481
• 关键词: Adenoviridae; clinical research; neoplasm /cancer; tissues

DESCRIPTION (provided by applicant): A number of characteristics of the Adenovirus type 5 (Ad5) make it an optimal gene therapy/virotherapy vector suitable for a wide array of cancer therapeutic approaches. Despite these advantages, overall ifficacy remains limited by sub-optimal adenovirus delivery to cancer tissues. 1 conceptual approach to overcome this limitation is to achieve an amplification effect of adenovirus infectivity via selective replication of the delivered adenovirus post-infection, such that lateral spread of progeny viruses may occur. In this approach, a conditionally replication-competent virus replicates oncolytically in transduced tumor cells but not in normal tissue. Production of adenovirus progeny from transduced tumor cells would then allow infection of the neighboring tumor cells. Using conditionally replicative adenoviruses (CRAds) represent a method to achieve efficient tumor cell oncolysis and mitigate tumor cell infection limitations. However, given that Ad5-based CRAds have a natural liver tropism, any background replication activity in normal tissues (and subsequent liver toxicity) presents a particularly critical problem that warrants development of novel approaches to improve cancer specificity. In this proposal, we aim specifically to reduce background replication activity in non-cancer cells by introducing 2 different levels of cancer targeting for the Ad5 E1A gene expression. First, this can be achieved by placing E1A gene, which is essential for CRAd replication function, under transcriptional control. To accomplish this, we will use the CXCR4 gene promoter, which has a distinct cancer-specific activation profile in squamous cell carcinomas of the head and neck (HNSCC). Second, we will introduce cancer-specific protein translational control by engineering a highly structured 5'-untranslated region (5'-UTR) sequence of the Fibroblast Growth Factor 2 (FGF2) upstream of the E1A mRNA coding sequence. This will render efficient translation of such a chimeric mRNA dependent upon the translation initiation factor elF-4E, which is expressed in limiting amounts in most normal tissues and is over expressed in most cancer cells. Thus, we hypothesize that the dual level of cancer-specific E1A mRNA transcription together with cancer-specific protein translation will significantly enhance target expression of E1A gene to cancer tissues beyond the use of either control element alone, and thereby dramatically improve cancer-specific replication of the CRAd. The successful completion of the proposed research to develop and validate the principle of dual-targeting of transgene expression in HNSCC cell lines, will result in a totally new class of CRAds for cancer virotherapy.

描述（由申请人提供）：腺病毒5型（Ad5）的许多特征使其成为适合多种癌症治疗方法的最佳基因治疗/病毒治疗载体。尽管有这些优势，但总体疗效仍然受到腺病毒向癌组织递送的次优限制。克服这一限制的一个概念性方法是通过在感染后选择性地复制传递的腺病毒来实现腺病毒感染性的放大效应，从而可能发生子代病毒的横向传播。在这种方法中，有条件复制能力的病毒在转导的肿瘤细胞中进行溶瘤性复制，而不是在正常组织中进行复制。从转导的肿瘤细胞中产生腺病毒后代，然后允许感染邻近的肿瘤细胞。使用条件复制腺病毒（CRAds）是一种实现高效肿瘤细胞溶瘤和减轻肿瘤细胞感染限制的方法。然而，鉴于基于ad5的crad具有天然的肝脏亲和性，正常组织中的任何背景复制活动（以及随后的肝毒性）都提出了一个特别关键的问题，需要开发新的方法来提高癌症特异性。在本研究中，我们通过引入2种不同水平的靶向Ad5 E1A基因表达来降低非癌细胞的背景复制活性。首先，这可以通过将对CRAd复制功能至关重要的E1A基因置于转录控制下来实现。为了实现这一点，我们将使用CXCR4基因启动子，它在头颈部鳞状细胞癌（HNSCC）中具有独特的癌症特异性激活谱。其次，我们将通过在E1A mRNA编码序列上游设计成纤维细胞生长因子2 （FGF2）的高度结构化的5'-非翻译区（5'-UTR）序列，引入癌症特异性蛋白质翻译控制。这将使这种依赖于翻译起始因子elF-4E的嵌合mRNA的有效翻译成为可能，elF-4E在大多数正常组织中表达量有限，在大多数癌细胞中过度表达。因此，我们假设癌症特异性E1A mRNA转录和癌症特异性蛋白翻译的双重水平将显著增强E1A基因在癌症组织中的靶表达，从而显著提高CRAd的癌症特异性复制。该研究的成功完成将开发和验证HNSCC细胞系中转基因表达的双重靶向原理，这将导致一种全新的用于癌症病毒治疗的crad。