Transport of Large Molecules and Viral Vectors in Tumors: Effects of Cytotoxic an

描述(申请人提供)：溶瘤病毒疗法是一种很有前途的方法，因为有效的转导和癌细胞特异性的病毒复制可以提高治疗效果。然而，溶瘤病毒的大小阻碍了它们在血管和间质中的运动，从而显著限制了它们对癌细胞的传递和抗肿瘤的效果。我们在当前资助期的发现表明，癌细胞凋亡产生了空隙和通道样结构，这增强了瘤内注射溶瘤单纯疱疹病毒(HSV)后的初始输送、病毒传播和治疗效果。但是，为了提高针对原发和转移肿瘤的溶瘤病毒治疗的系统疗效，必须确定能够改善静脉注射的病毒颗粒的血管外渗和瘤内分布的药物(例如细胞毒剂)或策略。在拟议的研究中，我们将检验靶向肿瘤血管将改善病毒载体的输送和溶瘤HSV的抗肿瘤效果的假设。肿瘤血管将以内皮细胞靶向药物(抗整合素14或15阻断抗体)或针对内皮细胞和癌细胞的细胞毒素(环磷酰胺、多西紫杉醇)为靶标。所选择的药物已知可诱导内皮细胞凋亡和重塑肿瘤血管。我们将使用多光子激光扫描显微镜来测量大颗粒的血管孔截断尺寸、血管重塑(如血管密度、直径、灌注量)以及植入免疫缺陷小鼠乳腺脂肪垫窗口的人乳腺癌细胞中病毒的外渗和扩散。由于病毒在血液中的半衰期很短(HSV~3小时)，我们将为每种药物确定大颗粒渗出的高峰时间。根据颗粒外渗的高峰期，系统注射溶瘤HSV，并测定与感染细胞相关的血管比例。将在肿瘤切片中评估内皮细胞凋亡和颗粒外渗之间的相关性。我们将测试在静脉注射溶瘤病毒之前给药内皮靶向药物或细胞毒素是否会延长乳腺脂肪垫肿瘤的生长延迟，并减少肺部自发转移的形成。我们还将确定细胞毒素或内皮靶向药物与溶瘤性HSV重复给药(循环)是否会改善大颗粒在肿瘤内的分布，以及溶瘤性HSV的扩散和治疗效果。我们希望这些转译研究的结果将确定单一的药物和/或方法，将加强血管外渗和肿瘤内病毒的传播，以及针对肿瘤的溶瘤病毒治疗的有效性。

DESCRIPTION (provided by applicant): Oncolytic virotherapy is a promising approach because the efficient transduction and cancer cell-specific viral replication can boost therapeutic efficacy. However, the large size of oncolytic viruses hinders their transvascular and interstitial movement, thus significantly limiting their delivery to cancer cells and anti- tumor efficacy. Our findings from the current funding period showed that cancer cell apoptosis produced void spaces and channel-like structures, which enhanced the initial delivery, viral spread and therapeutic efficacy of oncolytic herpes-simplex-virus (HSV) after intratumor injection. But in order to improve the systemic efficacy of oncolytic virotherapy targeted both at primary and metastatic tumors, it is essential to identify agents (e.g., cytotoxic agents) or strategies that will improve the vascular extravasation and intratumoral distribution of viral particles injected intravenously. In the proposed studies we will test the hypothesis that targeting tumor blood vessels will improve the delivery of viral vectors and the anti-tumor efficacy of oncolytic HSV. The tumor vasculature will be targeted with endothelial cell targeting agents (anti-integrin 14 or 15 blocking antibodies) or cytotoxics (cyclophosphamide, docetaxel) that target both endothelial and cancer cells. The agents selected are known to induce endothelial cell apoptosis and remodel the tumor vasculature. We will use multiphoton laser scanning microscopy to measure the vascular pore cutoff size of large particles, vascular remodeling (e.g. vessel density, diameter, perfusion), and virus extravasation and spread in human mammary carcinoma cells implanted in mammary fat pad windows in immunodeficient mice. Because of the short-half life of virus in blood (HSV ~ 3 hours), we will determine for each agent the peak-time of large particle extravasation. Based on the peak-time of particle extravasation, oncolytic HSV will be injected systemically and the fraction of vessels associated with infected cells will be determined. The correlation between endothelial apoptosis and particle extravasation will be assessed in tumor sections. We will test if the administration of endothelial targeting agents or cytotoxics before the intravenous injection of oncolytic virus will produce a longer tumor growth delay in mammary fat pad tumors and reduce spontaneous metastasis formation in the lung. We will also determine if the repeated administration (cycling) of cytotoxics or endothelial targeting agents with oncolytic HSV will improve the intratumoral distribution of large particles and the spread and therapeutic efficacy of oncolytic HSV. We expect that the results of these translational studies will identify single agents and / or approaches that will enhance the vascular extravasation and intratumoral spread of virus, and the efficacy of oncolytic virotherapy targeted at tumors.