Investigating TLR-agonist adjuvancy in STING-activating nanoparticle cancer vaccines

项目总结/摘要 针对黑色素瘤的治疗性疫苗尚未实现其临床潜力。多项III期临床试验 评估针对癌症-睾丸抗原、全细胞裂解物或癌症相关抗原的疫苗接种的功效 抗原未能达到其治疗终点。这种失败是由于缺乏抗原特异性细胞毒性T细胞 接种后淋巴细胞增殖。众所周知，疫苗的有效性需要时空引流， 用于刺激先天免疫以及抗原呈递的淋巴结的抗原和佐剂。因为 由于其大小和物理化学性质，纳米颗粒疫苗能够精确递送抗原和 淋巴结中相关细胞类型的佐剂。然而，细胞内危险信号的充分放大 可以保持挑战性。最近，我们实验室发现了一种两亲性嵌段共聚物PEG-b-PC 7A， 其直接结合并激活干扰素基因刺激物（STING）。这种先天免疫受体 通常识别胞质DNA，由环状GMP-AMP合酶（cGAS）加工成其天然配体2 '3'- 环GMP一AMP（cGAMP）。然而，PEG-b-PC 7A以cGAS-cGAMP非依赖性的方式直接结合STING。 过程，在抗原呈递细胞的吞噬作用后放大I型干扰素的分泌。我们有 显示了用PC 7A聚合物胶束和肿瘤相关抗原制剂接种荷瘤小鼠 会抑制肿瘤的生长虽然这种聚合物显示出显着的纳米粒子自组装，pH- 由于抗肿瘤免疫应答具有免疫反应性、内体溶解性和STING激活特性，因此抗肿瘤免疫应答可能是难治的。 在免疫抑制肿瘤模型中。因此，我将通过加入额外的免疫- 我们配方中的调节成分。特别地，炎性细胞因子的低表达将是一个重要的因素。 处理。我将用toll样受体（TLR）激动剂配制PC 7A纳米颗粒，以增加 以非冗余方式的细胞因子。虽然TLR和STING途径都集中在表达 在干扰素I中，衔接蛋白和信号传导途径（例如NF-κB）的差异可导致显著的细胞凋亡。 通过独特的激动剂接种后细胞因子表达的动力学变化。在这个应用程序中，我将 筛选和鉴定包封TLR激动剂的PC 7A纳米颗粒，用于改善干扰素刺激、CTL 代和抗肿瘤免疫。我假设TLR-7激动剂咪喹莫特（R837）包裹的PC 7A 由于TLR 7/STING-IRF 3/7诱导的免疫应答的非冗余性，纳米颗粒将显示出改善的抗肿瘤免疫性。 I型干扰素的转录。这种应用将通过制定一个新的协同类显示创新 TLR-STING激动剂纳米颗粒，该提案适合于该项目，因为它具有显著的 PC 7A聚合物纳米颗粒的特性。

Project Summary/Abstract Therapeutic vaccination against melanoma has yet to realize its clinical potential. Several phase III clinical trials assessing efficacy of vaccination against cancer-testis antigens, whole cell lysates, or cancer associated antigens failed to meet their therapeutic endpoints. This failure is due to lack of antigen-specific cytotoxic T lymphocyte proliferation after vaccination. It is known vaccine efficacy requires spatiotemporal draining of both antigen and adjuvant to lymph nodes for stimulating innate immunity as well as antigen presentation. Because of their size and physicochemical properties, nanoparticle vaccines enable precision delivery of both antigen and adjuvant to relevant cell types in the lymph node. However, sufficient amplification of intracellular danger signals can remain challenging. Recently, our laboratory has discovered an amphiphilic block copolymer, PEG-b-PC7A, which directly binds and activates the stimulator of interferon genes (STING). This innate immune receptor generally recognizes cytosolic DNA, processed by cyclic GMP-AMP Synthase (cGAS) to its natural ligand 2’3’- cyclic GMP-AMP (cGAMP). However, PEG-b-PC7A directly binds to STING in a cGAS-cGAMP-independent process, amplifying the secretion of type I interferons after phagocytosis by antigen presenting cells. We have shown vaccinating tumor-bearing mice with a PC7A polymeric micelle and tumor-associated antigen formulation will lead to tumor growth inhibition. While this polymer shows remarkable nanoparticle self-assembly, pH- responsiveness, endosomolytic, and STING activating properties, anti-tumor immune response can be refractory in immunosuppressive tumor models. Therefore, I will address this problem by incorporating additional immuno- modulatory components in our formulation. Particularly, low expression of inflammatory cytokines will be addressed. I will formulate PC7A nanoparticle with toll-like receptor (TLR) agonists to increase expression of cytokines in non-redundant manners. While the TLR and STING pathways both converge on expression of type I interferons, the differences in adaptor proteins and signaling pathways (e.g. NF-κB) can lead to significant changes in the kinetics of cytokines expression after vaccination by unique agonists. In this application I will screen and identify PC7A nanoparticles encapsulating TLR agonists for improved interferon stimulation, CTL generation, and anti-tumor immunity. I hypothesize the TLR-7 agonist, Imiquimod (R837), encapsulated PC7A nanoparticles will show improved anti-tumor immunity due to non-redundancy in TLR7/STING-IRF3/7-induced transcription of type I interferons. This application will show innovation by formulating a new class of synergetic TLR-STING agonist nanoparticles, and the proposal is suited for this project because of the remarkable properties of the PC7A polymeric nanoparticles.