Personalized Tumor RNA Loaded Lipid-Nanoparticles Prime the Systemic and Intratumoral Milieu for Response to Cancer Immunotherapy

Translation of nanoparticles (NPs) into human clinical trials for patients with refractory cancers has lagged due to unknown biologic reactivities of novel NP designs. To overcome these limitations, simple well-characterized mRNA lipid-NPs have been developed as cancer immunotherapeutic vaccines. While the preponderance of RNA lipid-NPs encoding for tumor-associated antigens or neoepitopes have been designed to target lymphoid organs, they remain encumbered by the profound intratumoral and systemic immunosuppression that may stymie an activated T cell response. Herein, we show that systemic localization of untargeted tumor RNA (derived from whole transcriptome) encapsulated in lipid-NPs, with excess positive charge, primes the peripheral and intratumoral milieu for response to immunotherapy. In immunologically resistant tumor models, these RNA-NPs activate the preponderance of systemic and intratumoral myeloid cells (characterized by coexpression of PD-L1 and CD86). Addition of immune checkpoint inhibitor...