Kinetic Assembly of Polymer-mRNA Nanoparticles Targets Circulating Monocytes to Enhance Cancer Immunotherapy

项目摘要 癌症疫苗显著推进了癌症免疫治疗; mRNA 疫苗通过特异性地递送mRNA而产生有效的抗肿瘤应答的前景 编码肿瘤相关抗原的抗原呈递细胞（APC）。然而，APC激活引起的 含有抗原mRNA的纳米颗粒是相当有限的。循环单核细胞提供了一个有希望的细胞靶点， 一种丰富的APC前体，可以沉积到脾脏，淋巴结和肿瘤组织， 极化和激活。本研究的总体目标是设计 动力学组装聚（β- 氨基酯 /mRNA纳米颗粒（KaNP），可特异性递送编码肿瘤抗原的mRNA 和免疫佐剂进入体内循环单核细胞，并证明这种新的免疫佐剂的安全性和有效性。 mRNA癌症疫苗平台。这项研究是建立在初步结果表明，生物降解 优化尺寸为400 nm的PBAE/mRNA KaNP介导的循环细胞的优先转染 静脉内（i. v.）注射，导致更有效的转染和沉积， 循环单核细胞和更高水平的肿瘤杀伤活性相比，标准的小尺寸 PBAE/mRNA纳米颗粒。在这项研究中，我们计划追求四个具体目标：（1）优化 PBAE/mRNA KaNP的组成、大小和表面功能以提高靶向mRNA递送效率 体内循环单核细胞中，（2）表征PBAE/mRNA KaNP的药代动力学特征并确定 体内转染循环单核细胞的功能，（3）评估PBAE/mRNA的免疫治疗功效 在小鼠肿瘤模型中与TLR 9和STING激动剂组合抑制肿瘤生长的KaNP，和 (4)开发符合GMP、货架稳定的冻干PBAE/mRNA KaNP制剂，并验证疗效 在小鼠模型中。如果成功的话，这项研究将揭示以前的结构-功能关系。 对于基因治疗载体来说，难以达到的尺寸范围（200-1000 nm），证明循环单核细胞是一种有效的 mRNA治疗靶点及KaNP转染的循环单核细胞在增强抗肿瘤中的作用 免疫应答，并启发合理设计用于治疗实体瘤新的基于mRNA的免疫疗法 肿瘤和转移性癌症。

PROJECT SUMMARY Cancer vaccines have significantly advanced cancer immunotherapy; and recent successes of mRNA vaccines have raised prospect of generating potent anti-tumor response by specifically delivering mRNAs encoding tumor-associated antigens to antigen presenting cells (APCs). However, APC activation elicited by nanoparticles containing antigen mRNAs is rather limited. Circulating monocytes offer a promising cell target as an abundant APC precursor that can be deposited to spleen, lymph nodes, and tumor tissue following polarization and activation. The overall objective of this study is to engineer kinetically assembled poly(beta- amino ester) (PBAE) /mRNA nanoparticles (KaNPs) that can specifically deliver mRNAs encoding tumor antigens and immunoadjuvants into circulating monocytes in vivo and demonstrate the safety and efficacy of this new mRNA cancer vaccine platform. This study is built on the preliminary results showing biodegradable PBAE/mRNA KaNPs with an optimized size of 400 nm mediated preferential transfection of circulating monocytes following intravenous (i.v.) injection, leading to more effective transfection and deposition of circulating monocytes and a higher level of tumor-killing activity compared to the standard small size PBAE/mRNA nanoparticles. In this proposed study, we plan to pursue four specific aims: (1) optimize the composition, size, and surface functionality of PBAE/mRNA KaNPs to improve targeted mRNA delivery efficiency into circulating monocytes in vivo, (2) characterize pharmacokinetic profile of PBAE/mRNA KaNPs and define functions of transfected circulating monocytes in vivo, (3) assess the immunotherapeutic efficacy of PBAE/mRNA KaNPs in suppressing tumor growth in combination with TLR9 and STING agonists in mouse tumor models, and (4) develop an GMP-compliant, shelf-stable, lyophilized PBAE/mRNA KaNP formulation and validate the efficacy in a mouse model. If successful, this study will uncover structure-function relationships in a previously inaccessible size range (200–1000 nm) for gene therapy carriers, demonstrate circulating monocytes as a potent mRNA therapeutic target and the role of KaNP-transfected circulating monocytes in potentiating antitumor immune responses, and inspire rational design of new mRNA-based immunotherapies for treatment of solid tumors and metastatic cancers.