Sayour et al. tested a nanoparticle vaccine consisting of tumor mRNA encapsulated in positively charged lipids to broadly target multiple organs. In mice, systemic administration of mRNA-NPs activated splenic and intratumoral CD11c+ myeloid cells, including APCs, and mediated the systemic release of Type I IFN from pDCs, which upregulated PD-L1 expression in APCs. In combinations with PD-L1 inhibition, the number of PD-1+CD8+ T cells increased, survival increased, and immunologically cold tumors were sensitized. In a canine with spontaneous malignant glioma, mRNA-NPs were safe and biologically active, but conferred no clinical benefit.
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 inhibitors (ICIs) (to animals primed with RNA-NPs) augments peripheral/intratumoral PD-1(+)CD8(+) cells and mediates synergistic antitumor efficacy in settings where ICIs alone do not confer therapeutic benefit. These synergistic effects are mediated by type I interferon released from plasmacytoid dendritic cells (pDCs). In translational studies, personalized mRNA-NPs were safe and active in a client-owned canine with a spontaneous malignant glioma. In summary, we demonstrate widespread immune activation from tumor loaded RNA-NPs concomitant with inducible PD-L1 expression that can be therapeutically exploited. While immunotherapy remains effective for only a subset of cancer patients, combination therapy with systemic immunomodulating RNA-NPs may broaden its therapeutic potency.
Author Info: (1) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Med
Author Info: (1) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (2) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (3) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (4) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (5) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (6) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (7) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (8) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (9) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (10) Department of Pathology, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (11) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. Department of Neuroscience, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (12) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (13) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (14) Department of Infectious Disease, College of Veterinary Medicine , University of Florida , Gainesville , Florida 32611 , United States. (15) Department of Small Animal Clinical Sciences, College of Veterinary Medicine , University of Florida , Gainesville , Florida 32611 , United States. (16) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States. (17) Preston A. Wells Jr. Center for Brain Tumor Therapy, UF Brain Tumor Immunotherapy Program, McKnight Brain Institute, Lillian S. Wells Department of Neurosurgery, College of Medicine , University of Florida , Gainesville , Florida 32611 , United States.
