Tumor and Stromal Targeting by Oncolytic Viruses

描述（由申请人提供）：全身给药后的递送不足和肿瘤扩散仍然是限制全身给药溶瘤病毒治疗癌症的疗效的主要未解决障碍。这是这些药物临床前和临床开发的重要限速步骤。肿瘤间质（肿瘤内皮、肿瘤成纤维细胞和细胞外基质）导致溶瘤剂的疗效差，因为它为病毒进入和体内肿瘤细胞中的复制创造了“屏障”。我们的长期目标是通过了解病毒、肿瘤和间质之间的相互作用，并在治疗上利用它们来提高全身施用溶瘤病毒的功效。本申请的总体目标是追求该目标的下一步，其是表征溶瘤麻疹病毒通过尿激酶受体（具有称为MV-uPA的病毒）（一种关键的肿瘤/基质细胞表面糖蛋白）靶向肿瘤基质和血管的特异性和治疗效果。本申请的中心假设是选择性靶向肿瘤基质/脉管系统的病毒uPAR将显著增强病毒对原发性肿瘤和转移的作用。拟议研究的基本原理是，了解溶瘤病毒如何与肿瘤基质的重要成分相互作用，将有助于创造“更智能”，更安全的溶瘤病毒载体，具有更好的治疗窗口。这项拟议中的研究与NIH的使命有关，因为它涉及开发更安全、更有效的生物制剂来对抗癌症。在强有力的初步数据的指导下，将通过追求三个具体目标来检验中心假设：1）表征MV-uPA在同系小鼠癌症模型中的肿瘤选择性和病毒-宿主相互作用; 2）进一步表征MV-uPA在乳腺癌模型中靶向肿瘤和基质尿激酶受体的体内作用; 3）研究MV-uPA的肿瘤血管靶向性及其对病毒抗肿瘤作用的影响。目的1利用分子生物学和免疫组化技术研究uPAR重靶向麻疹病毒全身给药后的肿瘤选择性、病毒复制和器官生物分布。此外，我们将在免疫活性乳腺癌和结肠癌模型中表征病毒的安全性和有效性剂量反应。在目标2中，我们将使用体内成像技术表征uPA重靶向麻疹病毒的抗转移活性。我们还将表征MV-uPA靶向基质细胞的能力，以及其在抗肿瘤功效方面的后果。在目标3中，我们将表征病毒/内皮相互作用的动力学，因为它们涉及病毒的潜在抗血管生成作用，以及uPAR靶向病毒通过肿瘤内皮增强病毒体内递送到乳腺肿瘤中的能力。该方法具有创新性和重要性，因为它将带来关于病毒和基质之间体内相互作用的新知识，这将转化为更好的溶瘤病毒药物的开发，以造福癌症患者。

DESCRIPTION (provided by applicant): Inadequate delivery and tumor spread after systemic administration remains a major -unsolved- obstacle that limits the efficacy of systemically administered oncolytic viruses for the treatment of cancer. This is a significant, rate limiting step for the pre-clinical and clinical development of these agents. The tumor stroma (tumor endothelium, tumor fibroblasts, and extracellular matrix) contributes to the poor efficacy of oncolytic agents, as it creates a "barrier" for viral entry and replication in tumor cells in vivo. Our long term goal is to improve the efficacy of systemically administered oncolytic viruses by understanding the interactions among virus, tumor and stroma, and exploiting them therapeutically. The overall objective of this application, which is the next step in the pursuit of that goal, is to characterize the specificity and therapeutic effects of tumor stromal and vascular targeting of oncolytic measles viruses via the urokinase receptor (with a virus called MV- uPA), a critical tumor/stromal cell surface glycoprotein. The central hypothesis of this application is that selective viral uPAR targeting of tumor stroma/vasculature will significantly enhance the virus' effects against primary tumors and metastases. The rationale for the proposed research is that understanding of how oncolytic viruses interact with important components of the tumor stroma will help create "smarter", safer oncolytic viral vectors with a better therapeutic window. The proposed research is relevant to NIH's mission, in that it pertains to developing safer, more effective biological agents for the fight against cancer. Guided by strong preliminary data, the central hypothesis will be tested by pursuing three specific aims: 1) Characterize MV-uPA's tumor selectivity and virus-host interactions in syngeneic murine cancer models; 2) to further characterize the in vivo effects of tumor and stromal urokinase receptor targeting by MV-uPA in breast cancer models; and 3) to characterize the tumor vascular targeting abilities of MV-uPA and its contribution to the virus' overall anti-tumor effects. Aim 1 will investigate the tumor selectivity, viral replication and organ biodistribution, of uPAR retargeted measles viruses, after systemic administration, using molecular and immunohistochemical techniques. In addition, we will characterize the safety and efficacy dose response to the virus in immunocompetent mammary and colon cancer models. In aim 2, we will characterize the antimetastatic activity of uPA retargeted measles virus using, in vivo imaging techniques. We will also characterize MV-uPA's ability to target stromal cells, and its consequences in regards to antitumor efficacy. In aim 3, we will characterize the kinetics of virus/endothelial interactions as they pertain to the virus' potential antiangiogenic effects, and the ability of the uPAR targeted viruses to enhance viral delivery into breast tumor in vivo via tumor endothelium. The approach is innovative and significant, because it will bring new knowledge on in vivo interactions between virus and stroma, which will translate into the development of better oncolytic viral agents for the benefit of patients with cancer.