Vaccination against antigens induced by TAP downregulation in concurrent and future tumors

对患者接种主要针对患者特定新抗原的疫苗在以下方面构成了重大挑战 以哪些抗原为靶点，并且仅限于在其肿瘤中表达新抗原的患者的子集。在这里我们 建议制定一种广泛适用的疫苗接种策略，以对抗一组共同的预定义抗原，这些抗原 是通过下调抗原处理途径的关键介质在肿瘤细胞中实验诱导的， TAP、ERAAP和不变链(II)。TAP或ERAAP的基因消融导致I类- 能够刺激T细胞反应并抑制TAP或ERAAP生长的限制性新表位 肿瘤细胞缺陷，而不变链下调(II)导致其他 神秘的内源性II类表位。针对TAP、ERAAP或II下调诱导的疫苗接种 抗原将构成一种广泛适用的新抗原靶向疫苗接种策略，适用于患有 同时、复发和未来的肿瘤，克服了针对突变接种疫苗的主要限制- 产生患者特有的新抗原。 我们的研究表明，接种针对TAP下调诱导的疫苗的建议得到了支持 抗原，通过与CpG寡核苷酸(CpG-DNA)偶联，将TAP siRNA靶向驻留在小鼠的DC TAP siRNA)，比接种疫苗对原型患者特异性突变更有效 新抗原，没有可测量的毒性，并抑制同时和未来的肿瘤的生长。 复发和癌前疾病的模型，假设TAP在发展过程中也下调 使用广泛的核仁素结合适体将TAP siRNA原位靶向肿瘤细胞(Nucl-TAP SiRNA)。 这项建议的目标是优化诱导新抗原接种策略，以便设置 临床试验评价阶段：(1)。开发诱导新抗原的最佳方法，方法是 抑制抗原加工的关键介质TAP、ERAAP和II。我们假设，鉴于 CD4+和CD8+T细胞免疫、TAP或ERAAP下调诱导CD8+T细胞的协同作用 刺激CD4+T细胞应答的应答与II类分子的下调相结合将是最有效的 组合。(2)评估与细胞靶向免疫增强方式的组合。我们会 测试两种新的肿瘤和T细胞靶向策略，以使肿瘤对促炎免疫敏感 反应，即将“冷”的肿瘤病变转变为“热的”肿瘤病变，并促进肿瘤在肿瘤内的聚集- 常驻CD8+T细胞(Trm)。(3)开发用于临床试验的先导化合物。找出最好的- 类内靶点，TAP，ERAAP，II，或其组合，在体外刺激人CD8+T细胞反应 CpG-siRNA处理的DC，将识别Nucl-siRNA处理的肿瘤细胞诱导提呈 肿瘤细胞上的所述抗原。

Vaccination of patients against mostly patient-specific neoantigens is posing major challenges in terms of which antigens to target and is limited to a subset of patients expressing neoantigens in their tumors. Here we propose to develop a broadly applicable vaccination strategy against a common set of predefined antigens that are experimentally induced in tumor cells by downregulation of key mediators of antigen processing pathway, TAP, ERAAP and Invariant chain (Ii). Genetic ablation of TAP or ERAAP leads to the presentation of class I- restricted neoepitopes that are capable of stimulating T cell responses and inhibit the growth of TAP or ERAAP deficient tumor cells whereas downregulation of Invariant chain (Ii) leads to the presentation of otherwise cryptic endogenous class II epitopes. Vaccination against the TAP, ERAAP or Ii downregulation-induced antigens will constitute a broadly applicable neoantigen-targeted vaccination strategy for patients with concurrent, recurrent, and future tumors that overcomes the main limitations of vaccinating against mutation- generated patient-specific neoantigens. Proposal is supported by our studies showing that vaccination against the TAP downregulation-induced antigens, by targeting a TAP siRNA to resident DC in mice thru conjugation to a CpG oligonucleotide (CpG- TAP siRNA), was more effective than vaccination against prototypic patient-specific mutation-generated neoantigens, was devoid of measurable toxicity, and inhibited the growth of concurrent and future tumors in models of recurrence and premalignant disease, provided TAP was also downregulated in the developing tumors using a broad-range nucleolin binding aptamer to target the TAP siRNA to tumor cells in situ (Nucl-TAP siRNA). The goal of this proposal is to optimize the induced neoantigen vaccination strategy in order to set the stage for its evaluation in clinical trials: (1). To develop optimal methods to induce neoantigens by inhibiting key mediators of antigen processing, TAP, ERAAP, and Ii. We hypothesize that given the synergy between CD4+ and CD8+ T cell immunity, TAP or ERAAP downregulation that elicit CD8+ T cell responses combined with Ii downregulation that elicit CD4+ T cell responses will be the most effective combinations. (2) To evaluate combinations with cell-targeted immune potentiating modalities. We will test two novel tumor- and T cell-targeted strategies, to sensitize tumors to a proinflammatory immune response, i.e. convert “cold” to “hot” tumor lesions, and to promote the intratumoral accumulation of tumor- resident CD8+ T cells (Trm), respectively. (3) Develop lead compounds for clinical trials. Identify the best- in-class targets, TAP, ERAAP, Ii, or combination of, to stimulate human CD8+ T cell responses in vitro using CpG-siRNA treated DC, that will recognize tumor cells treated with Nucl-siRNA to induce the presentation of said antigens on the tumor cells.