CELLULAR PATHWAYS AFFECTING ONCOLYTIC VIRUS-HOST INTERACTIONS IN CANCER

 描述(申请人提供)：胰腺癌，其中约95%是胰腺导管腺癌(PDAC)，是所有癌症中预后最差的，不久将成为美国癌症相关死亡的第二大原因。目前的治疗方案显然不利于患者的生存。溶瘤病毒疗法是一种相对较新的抗癌方法，它利用具有复制能力的病毒特异性地感染和杀死 肿瘤细胞。水泡性口炎病毒(VSV)就是这样一种溶瘤病毒，目前已处于治疗肝细胞癌的I期临床试验阶段。我们最近的研究表明，VSV在体外和体内对大多数被测试的人PDAC细胞株都是有效的。然而，我们发现一些PDAC细胞株对VSV感染、复制和病毒介导的溶瘤具有抵抗力，这主要是由于抗病毒基因的结构性表达。我们的目标是更好地了解和靶向决定基于VSV的OV治疗成功的PDAC细胞通路，并开发合理的联合治疗方法来提高OV的疗效和/或克服OV的耐药性。这些实验是基于我们最近发表的工作和初步研究，这些研究分析了VSV在体外和体内对一些PDAC细胞株的作用，初步表征了PDAC细胞系的一般细胞特性和对VSV的通透性，并确定了显著改善PDAC细胞中VSV性能的小分子抑制剂。在目标1中，我们将识别并靶向导致对VSV耐药的PDAC细胞系中抗病毒基因的结构性表达的细胞因子；识别与VSV耐药有关的特定抗病毒基因；并研究化疗耐药的发展如何影响PDAC细胞对VSV的耐受性。在目标2中，我们将在体内测试VSV与我们初步研究中显示的小分子抑制剂的组合，以成功下调抗病毒基因，并刺激VSV复制和溶瘤。重要的是，这两个目标都将评估这些新的组合方法如何影响基于VSV的OV治疗的选择性和安全性。我们的研究将开发一种更有效的VSV溶瘤疗法，拓宽可成功应用该疗法的PDAC表型的范围，并将导致开发预筛查方法来识别对特定OV治疗有反应的癌症患者。虽然这项提案的重点是VSV对抗PDAC，但它将定义可能影响其他OV和肿瘤系统的细胞因素和途径。

 DESCRIPTION (provided by applicant): Pancreatic cancers, about 95% of which are pancreatic ductal adenocarcinoma (PDAC), have the worst prognosis of all cancers and will soon be the second leading cause of cancer-related deaths in the United States. Current treatment regimens clearly fail to benefit patient survival. Oncolytic virotherapy is a relatively new anticancer approach that utilizes replication-competent viruses to specifically infect and kill tumor cells. Vesicular stomatitis virus (VSV) is one such oncolytic virus (OV) and is already in a phase I clinical trial against hepatocellular carcinoma. Our recent studies demonstrated that VSV is effective against the majority of tested human PDAC cell lines, both in vitro and in vivo. However, we found that some PDAC cell lines are resistant to VSV infection, replication and virus-mediated oncolysis, largely due to the constitutive expression of antiviral genes. Our goal is to better understand and target PDAC cellular pathways determining the success of VSV- based OV therapy and to develop rational combination therapy approaches to enhance OV efficacy and/or overcome resistance to OVs. The proposed experiments are based on our recently published work and preliminary studies that analyzed VSV against a number of PDAC cell lines in vitro and in vivo, made an initial characterization of PDAC cells lines in regard to their general cellular characteristics and permissiveness to VSV, and identified small molecule inhibitors dramatically improving VSV performance in PDAC cells. In Aim 1, we will identify and target cellular factors leading to the constitutive expression of antiviral genes in PDAC cell line resistant to VSV; identify specific antiviral genes responsible for resistance of PDAC cell lines t VSV; and investigate how development of chemoresistance affects permissiveness of PDAC cells to VSV. In Aim 2, we will test in vivo VSV in combination with small molecule inhibitors shown in our preliminary studies to successfully down-regulate antiviral genes and stimulate VSV replication and oncolysis. Importantly, both aims will evaluate how these novel combination approaches affect oncoselectivity and safety of VSV-based OV therapy. Our studies will develop a more effective VSV oncolytic therapy, broaden the spectrum of PDAC phenotypes to which this treatment can be successfully applied, and will lead to development of prescreening approaches to identify cancer patients who will be responsive to specific OV treatments. While this proposal is focused on VSV against PDAC, it will define cellular factors and pathways likely affecting other OVs and tumor systems.