Development of EGFR-Targeted Oncolytic Adenovirus for Therapy of Oral Cancers

描述(申请人提供)：口腔鳞状细胞癌(OSCC)是全球第五大最常见的癌症。常见的治疗方法仍然包括放射治疗和导致毁容的手术，这需要更小的侵入性治疗，如靶向治疗。条件性复制型腺病毒(CRAds)具有临床安全性高、感染性强等优点，是一种很有前途的抗癌药物。CRAds的抗肿瘤作用是基于一种自然的裂解机制(溶瘤作用)对癌细胞的特异性杀伤，这与抗体治疗不同，并有可能克服复发和转移性口腔鳞癌的抗体治疗耐药性。最新的基因技术允许将具有工程化靶向性的小“亲和体”分子掺入到Ad衣壳蛋白“纤维”中。我们寻求将这种纤维修饰技术与最近开发的表皮生长因子受体(EGFR/ErbB1)特异性结合起来率先实施，以开发一种转导重定向到这种在大多数头颈部和口腔癌中过度表达的癌症生物标记物的CRAd试剂。此外，CXCR4肿瘤特异性启动子(TSP)将CRAd复制靶向口腔鳞癌，在口腔癌中具有高度特异性的激活特征。另一方面，CRAd潜在的有限肿瘤内扩散可以通过“武装”分泌蛋白MDA-7/IL24基因来补偿，该基因的表达通过旁观者机制以癌症特异性的方式诱导细胞凋亡，与CRAd的溶瘤功能完全兼容。在这项应用中，我们还建议通过一种独特的非侵入性多模式成像方法，在常用的口腔鳞癌裸鼠移植模型中测试其复制特性和溶瘤潜力，从而初步验证EGFR靶向的CXCR4-CRAd。通过口腔鳞癌肿瘤细胞的生物发光来监测肿瘤的降解，稳定表达萤火虫荧光素酶及其与复制的CRAd与红外荧光蛋白1.4(IFP1.4)标记的衣壳所产生的红色荧光的相关性，将为初步评估EGFR/OSCC双靶向效益提供重要工具。 公共卫生相关性：拟议研究的目标是开发针对肿瘤标记物EGFR/Erb1的新一代溶瘤腺病毒，用于治疗和早期发现人类头颈部，特别是口腔癌。新病毒的衣壳将被基因标记上最近开发的人类EGFR特异性亲和抗体，以转导重定向到EGFR。另一方面，新一代成像报告红外荧光蛋白1.4(IFP1.4)将被用于对病毒颗粒进行基因标记，以改进对病毒在肿瘤或生物分布中复制和传播的非侵入性实时成像。我们还建议通过基于成像的评估其在口腔鳞癌肿瘤中的复制以及使用最先进的多模式成像方法评估其在口腔鳞癌异种移植小鼠模型中的溶瘤效果来执行新药物的初步靶向验证步骤。

DESCRIPTION (provided by applicant): Oral squamous cell carcinoma (OSCC) is the fifth most frequently occurring cancer worldwide. Common treatments still include radiation therapy and surgery leading to disfiguring impairments, which warrant less invasive treatments such as targeted therapies. Conditionally Replicative Adenoviruses (CRAds) are promising anti-cancer agents owing to their clinical safety and high infectivity. The anti-tumor effect of CRAds is based on specific killing of cancer cells by a natural lytic mechanism (oncolysis), which is distinct from that of antibody therapy and potentially allows overcoming antibody therapy resistance of recurrent and metastatic OSCC. The most recent genetic technology allows incorporation of a small "affibody" molecule with engineered targeting specificity into the Ad capsid protein "fiber". We seek to pioneer implementation of this fiber modification technology in conjunction with a recently developed Epidermal Growth Factor Receptor (EGFR/ErbB1)-specific affibody for the development of a CRAd agent transductionally re-targeted to this cancer biomarker, overexpressed in most head and neck and oral cancers. Furthermore, the CRAd replication will be targeted to OSCC by CXCR4 Tumor Specific Promoter (TSP) with highly specific activation profile in oral cancers. On the other hand, a potentially limited intratumoral spread of the CRAd could be compensated by "arming" with a secretory protein MDA-7/IL24 gene, whose expression induces cell apoptosis in cancer-specific fashion via a bystander mechanism, fully compatible with oncolytic function of CRAd. In this application we also propose to perform an initial validation of the EGFR-targeted CXCR4-CRAd by testing its replication properties and oncolytic potential in the commonly used OSCC xenograft model in nude mice by a unique noninvasive multimodality imaging approach. Monitoring of tumor oncolysis via bioluminescence of OSCC tumor cells, stably expressing firefly luciferase and its correlation with intratumoral accumulation of red fluorescence, produced by the replicating CRAd with Infrared Fluorescent Protein 1.4 (IFP1.4)-labeled capsid, will provide an important tool for the initial assessment of the EGFR/OSCC dual targeting benefit. PUBLIC HEALTH RELEVANCE: The goal of the proposed research is to develop a new generation oncolytic adenovirus targeted to tumor marker EGFR/Erb1 for therapy and early detection of human head and neck and, particularly, oral cancers. The capsid of the new virus will be genetically tagged with a recently developed human EGFR-specific affibody for its transductional retargeting to EGFR. On the other hand, a new generation imaging reporter Infrared Fluorescent Protein 1.4 (IFP1.4) will be used to genetically label the viral particles to improve noninvasive real time imaging of viral replication and spread in tumors or biodistribution. We also propose to perform an initial targeting validation step of the new agent by imaging-based assessment of its replication in OSCC tumors and evaluation of its oncolytic efficacy in OSCC xenograft mouse model using a state-of-the-art multimodality imaging approach.