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

描述（由申请人提供）：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疫苗可以诱导有效的外周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（Tregs），以及肿瘤运动基质。虽然针对Tregs或肿瘤相关成纤维细胞（CAFs，肿瘤基质的主要成分）的疫苗策略在动物模型中产生了完全的应答，但由于效应t细胞功能被侵蚀和/或破坏，肿瘤不可避免地复发。我们现在假设，通过不仅针对肿瘤和treg，而且针对caf， t细胞效应功能将保留更长时间，局部“促瘤天堂”将被破坏，从而导致持续的肿瘤缓解。我们进一步假设，在肿瘤中产生的强效免疫刺激环境将导致表位扩散，作为新激活的抗原呈递细胞在肿瘤基质中“交叉呈递”垂死的肿瘤细胞。为了验证这些假设，我们将利用我们的初步研究，我们已经证明在DC中沉默负调节因子A20可以克服Treg介导的免疫抑制，从而在B16模型中产生有效的抗肿瘤反应。此外，我们已经证明a20沉默的DC疫苗可以诱导对CAFs细胞表面表达的成纤维细胞激活蛋白（FAP）的有效免疫反应。使用B16模型，我们将在Aim 1中评估共表达A20-shRNA、FAP和TRP2 （DC- sha20 -FAP-TRP2）的DC疫苗是否逆转了抑制肿瘤的微环境，促进了t细胞向肿瘤的浸润，并在Aim 2中确定我们的疫苗诱导旁站t细胞反应（表位扩散）的能力，从而消除肿瘤抗原丢失变异。在Aim 3中，我们将在自发性小鼠Hgf-Cdk4R24c黑色素瘤模型中评估我们的疫苗的有效性和安全性。这项拟议的研究具有高度创新性，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，同时在单一疫苗配方中克服treg介导的免疫抑制。如果这种临床前方法是成功的，并且临床验证是合理的，我们就有资源来准备符合适当的良好生产规范安全标准的载体和细胞成分，并将为这样的研究寻求单独的资金。

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.