Integrating innate and adaptive immunity in cancer therapy

描述(由申请人提供)：将IL-12和GM-CSF持续输送到肿瘤微环境中可以快速激活先前存在的CD8+T效应/记忆细胞，促进消除CD4+CD25+Foxp3+T-抑制细胞，并导致在肿瘤引流淋巴结(TDLN)中启动次级CD8+T-效应反应。然而，肿瘤免疫抑制的逆转是短暂的，效应器激活之后是T抑制细胞的戏剧性反弹和T效应器静止的恢复。重新刺激会导致调节性反弹的加剧，最终导致治疗效果的丧失。最近的研究表明，CD8+T效应细胞启动和T抑制细胞反弹都是由治疗后招募到TDLN的同一批髓系树突状细胞(DC)介导的。更重要的是，干扰素？对于初始免疫原性和随后的耐受性DC(TDC)表型的形成都是必需的。在这一应用中将测试的广泛假设是，干扰素驱动的DC中的免疫原性和耐受性通路可以解偶联，选择性地抑制耐受性通路将中和稳态T抑制细胞反弹，导致持久的肿瘤消退。为此，目标1研究旨在阐明干扰素诱导的免疫原性DC(IDC)向TDC分化的鲜为人知的机制。更具体地说，阐明了选定的干扰素调节因子(IRF)在IDC和TDC表型分化中的特定作用，以确定可以选择性阻断TDC发展和持久性的潜在检查点。在目标2中，测试了两种不同的策略，旨在通过使用独特的体内大分子递送技术来消除反调节。首先，通过siRNA/金纳米棒复合体和缓释细胞因子/小分子药物制剂来靶向治疗后TDC分化和活性的潜在调节因子，包括IRF-8、SOCS-1、IDO-1/2、GCN-2和MyD88以及AIM 1中确定的其他候选药物。第二，基于最近的发现表明T抑制细胞表型具有相当大的可塑性，上述技术被用于通过Foxp3沉默和递送TH1/TH17促进细胞因子来重新编程反弹的T抑制细胞。在目标3中，在两个临床相关的肿瘤模型中研究了上述方法的长期治疗潜力。首先，利用外科转移模型来确定局部消除T抑制细胞反弹是否会加强对播散性疾病的根除。在第二个模型中，在一个先进的原发肿瘤模型中，评估了慢性免疫疗法在不可切除疾病的长期治疗中的作用。阐明治疗诱导的内稳态反调节的分子基础，并确定潜在的调节检查点，可以中和T抑制因子反弹，这代表了一种新的范式，如果成功，可以显著提高基于免疫的治疗的临床疗效。 与公共健康相关：这项提案将定义短路治疗诱导的抗肿瘤细胞毒细胞活性的动态平衡调节反弹的分子机制。对治疗本身如何导致动员监管反应对措施的描述，预计将揭示可作为废除监管反弹的目标的检查点。为此，新的siRNA、重组蛋白和小分子药物的控释制剂与治疗相结合，针对预期的检查点和重新编程调节细胞，以实现持久的肿瘤消退。

DESCRIPTION (provided by applicant): Sustained delivery of Interleukin-12 and GM-CSF to the tumor microenvironment induces rapid activation of pre-existing CD8+ Teffector/memory cells, promotes elimination of CD4+ CD25+ Foxp3+ T-suppressor cells and results in the priming of a secondary CD8+ T-effector response in the tumor-draining lymph nodes (TDLN). However, reversal of tumor immune suppression is transient and effector activation is followed by a dramatic rebound of T-suppressor cells and return of T-effector quiescence. Re-stimulation results in the intensification of the regulatory rebound and ultimately, in the loss of therapeutic efficacy. Recent work demonstrated that both CD8+ T-effector cell priming and T-suppressor cell rebound were mediated by the same myeloid Dendritic cell (DC) population that was recruited to the TDLN following treatment. More importantly, IFN? was required for the development of both the initial immunogenic and the subsequent tolerogenic DC (tDC) phenotype. The broad hypothesis that will be tested in this application is that IFN?-driven immunogenic and tolerogenic pathways in DC can be uncoupled and that selective inhibition of the tolerogenic pathway will neutralize the homeostatic T-suppressor cell rebound, resulting in durable tumor regression. To this end, Aim 1 studies are designed to delineate the little-known mechanisms controlling the IFN?-driven differentiation of immunogenic DC (iDC) to tDC. More specifically, the specific roles of selected interferon regulatory factors (IRFs) in the differentiation of iDC and tDC phenotypes are elucidated to identify potential checkpoints that can be targeted for selective blocking of tDC development and persistence. In Aim 2, two different strategies aimed at abrogating counter-regulation via the use of unique in vivo macromolecule delivery technologies are tested. First, potential regulators of post-therapy tDC differentiation and activity, including IRF-8, SOCS-1, IDO-1/2, GCN-2 and MyD88 as well as additional candidates that are identified in Aim 1, are targeted via siRNA/gold nanorod complexes and sustained-release cytokine/small molecule drug formulations to block tDC function. Second, based on recent findings demonstrating considerable plasticity in T-suppressor cell phenotype, the above technologies are utilized to re-program rebounding T-suppressor cells via Foxp3 silencing and delivery of TH1/TH17-promoting cytokines. In Aim 3, the long-term curative potential of the above approach is investigated in two clinically-relevant tumor models. First, a surgical metastasis model is utilized to determine whether local abrogation of the T-suppressor cell rebound will result in enhanced eradication of disseminated disease. In the second model, the utility of chronic immune therapy in long-term management of non- resectable disease is evaluated in an advanced primary tumor model. Elucidation of the molecular basis of treatment-induced homeostatic counter-regulation and identification of potential regulatory checkpoints that can be targeted for neutralization of the T-suppressor rebound represents a new paradigm, which if successful, can significantly improve clinical efficacy of immune-based therapies. PUBLIC HEALTH RELEVANCE: This proposal will define the molecular mechanisms underlying the homeostatic regulatory rebound that short-circuits therapy-induced antitumor cytotoxic cell activity. Delineation of how treatment itself leads to the mobilization of a regulatory counter-response is expected to reveal checkpoints that can be targeted for abrogation of the regulatory rebound. To this end, novel controlled-release formulations of siRNA, recombinant proteins and small molecule drugs are utilized in conjunction with therapy to target anticipated checkpoints and reprogram regulatory cells to achieve durable tumor regression.