Cancer and Stroma-Targeted Immunotherapy with a Gentically Modified DC Vaccine

描述(申请人提供)：该项目的目的是开发一种有效的实体肿瘤树突状细胞(DC)疫苗。虽然DC疫苗可以诱导强大的外周T细胞免疫，但其抗肿瘤作用有限。这很可能是由于肿瘤内存在免疫抑制细胞，如调节性T细胞(Treg)以及肿瘤运动间质。虽然针对Tregs或癌症相关成纤维细胞(CAF)的疫苗策略已经在动物模型中产生了完全反应，但随着效应器T细胞功能的侵蚀和/或颠覆，肿瘤不可避免地会复发。我们现在假设，不仅以肿瘤和Tregs为靶点，而且以CAF为靶点，T细胞效应功能将保留更长时间，局部的促进肿瘤的天堂将被破坏，从而导致持续的肿瘤缓解。我们进一步假设，在肿瘤中创造的强大的免疫刺激环境将导致表位作为新激活的抗原提呈细胞在肿瘤间质中‘交叉呈现’死亡的肿瘤细胞中扩散。为了验证这些假设，我们将利用我们的初步研究，其中我们已经证明，沉默DC中的负调控因子A20可以克服Treg介导的免疫抑制，从而在B16模型中产生强大的抗肿瘤反应。此外，我们还发现A20沉默的DC疫苗可以诱导针对CAF细胞表面表达的成纤维细胞激活蛋白(FAP)的有效免疫应答。利用B16模型，我们将在目标1中评估共表达A20-shRNA、FAP和Trp2的DC疫苗(DC-shA20-FAP-Trp2)是否逆转了抑制性肿瘤微环境并促进T细胞向肿瘤的渗透，并在目标2中确定了我们的疫苗诱导旁观者T细胞反应(表位扩散)的效力，从而消除了肿瘤抗原丢失变体。在目标3中，我们将评估我们的疫苗在自发性小鼠HGF-CDK4R24c黑色素瘤模型中的有效性和安全性。这项拟议的研究具有很高的创新性，因为它将首次测试转基因DC诱导T细胞对癌细胞及其支持基质的反应的能力，同时克服单一疫苗配方中Treg介导的免疫抑制。如果这种临床前方法是成功的，并且临床验证似乎是合理的，我们有资源准备符合适当的良好制造规范安全标准的载体和细胞组件，并将为此类研究寻求单独的资金。 与公共健康相关：人体对癌症的免疫防御通常会失败，因为恶性肿瘤会主动抑制免疫系统。免疫系统不仅受到癌细胞的抑制，还受到周围非癌细胞的抑制。我们建议开发一种攻击癌细胞和周围免疫抑制细胞的疫苗。疫苗的效果将在动物模型中进行评估。

DESCRIPTION (provided by applicant): The intent of this project is to develop an effective dendritic cell (DC) vaccine for solid tumors. While DC vaccines can induce potent peripheral T-cell immunity, their antitumor effects have been limited. This is most likely due to the presence of immunosuppressive cells within the tumor, such as regulatory T cells (Tregs), as well as tumor sporting stroma. While vaccine strategies targeting Tregs or cancer associated fibroblasts (CAFs, the major component of tumor stroma) have produced complete responses in animal models, tumors inevitably recur, as effector T-cell functions are eroded and/or subverted. We now hypothesize that by targeting not only the tumor and Tregs, but also CAFs, T-cell effector function will be retained for longer and the local 'tumor promoting heaven' will be destroyed resulting in sustained tumor remissions. We further hypothesize that the potent immunostimulatory environment created in the tumor will result in epitope spreading as newly activated antigen presenting cells within the tumor stroma 'cross-present' dying tumor cells. To test these hypotheses we will take advantage of our preliminary studies in which we have demonstrated that silencing the negative regulator A20 in DC can overcome Treg mediated immune suppression resulting in potent antitumor responses in the B16 model. In addition, we have shown that an A20-silenced DC vaccine can induce potent immune responses against fibroblast activating protein (FAP) expressed on the cell surface of CAFs. Using the B16 model, we will evaluate in Aim 1 if a DC vaccine coexpressing A20-shRNA, FAP and TRP2 (DC-shA20-FAP-TRP2) reverses the suppressive tumor microenvironment and facilitates T-cell infiltration into tumors, and determine in Aim 2 the potency of our vaccine to induce bystander T-cell responses (epitope spreading), leading to elimination of tumor antigen loss variants. In Aim 3 we will then evaluate the efficacy and safety of our vaccine in a spontaneous murine Hgf-Cdk4R24c melanoma model. The proposed study is highly innovative since it will test for the first time the ability of genetically modified DCs to induce T-cell responses against cancer cells and their supporting stroma, while concomitantly overcoming Treg-mediated immunosuppression in a single vaccine formulation. If this pre-clinical approach is successful and clinical validation appears justified, we have the resources to prepare vector and cellular components that conform to the appropriate Good Manufacturing Practices safety standards, and will seek separate funding for such a study. PUBLIC HEALTH RELEVANCE: The body's immune defenses against cancers often fail because malignancies actively inhibit the immune system. The immune system is not only suppressed by the cancer cells but also by the surrounding none cancerous cells. We propose to develop a vaccine that attacks cancer cells and the immunosuppressive surrounding cells. The effect of the vaccine will be evaluated in animal models.