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

针对大多数患者特异性新抗原的患者疫苗接种在免疫治疗方面构成重大挑战。 靶向哪些抗原，并限于在其肿瘤中表达新抗原的患者亚组。这里我们 建议开发一种广泛适用的针对一组常见的预定义抗原的疫苗接种策略， 通过下调抗原加工途径的关键介质在肿瘤细胞中实验诱导， TAP、ERAAP和不变链（II）。TAP或ERAAP的基因切除导致I类- 能够刺激T细胞应答并抑制TAP或ERAAP生长的限制性新表位 缺乏肿瘤细胞，而下调不变链（Ii）导致的介绍，否则 隐蔽的内源性II类表位。针对TAP、ERAAP或Ii下调诱导的 抗原将构成一种广泛适用的新抗原靶向疫苗接种策略， 并发、复发和未来的肿瘤，克服了针对突变接种疫苗的主要局限性- 产生患者特异性新抗原。 我们的研究支持了这一提议，表明针对TAP下调的疫苗接种诱导了 抗原，通过缀合至CpG寡核苷酸（CpG- TAP siRNA）比针对原型患者特异性突变产生的疫苗接种更有效。 新抗原，没有可测量的毒性，并抑制并发和未来肿瘤的生长， 复发和癌前病变模型，前提是TAP在发展中国家也下调。 使用宽范围核仁素结合适体将TAP siRNA原位靶向肿瘤细胞（Nucl-TAP siRNA）。 该提案的目标是优化诱导的新抗原疫苗接种策略，以设定免疫应答。 临床试验评价阶段：（1）。开发诱导新抗原的最佳方法， 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下调之间协同作用，其引发CD8 + T细胞 与Ii下调相结合的诱导CD4 + T细胞应答将是最有效的 组合。(2)评价与细胞靶向免疫增强方式的组合。我们将 测试两种新的肿瘤和T细胞靶向策略，使肿瘤对促炎免疫敏感 反应，即将"冷"肿瘤病变转化为"热"肿瘤病变，并促进肿瘤的肿瘤内积聚。 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，以刺激体外人CD8 + T细胞应答， CpG-siRNA处理的DC，其将识别用Nucl-siRNA处理的肿瘤细胞以诱导CpG-siRNA的呈递。 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.