Nanoparticle-based immunotherapeutic platforms are emerging as radically different, biocompatible alternatives for viral-vectors. Liposomal nanoplexes already showed potential for clinical translation of mutanome specific personalized cancer-vaccines in human. Here, we report a novel nanoparticle platform technology for neoantigen specific mRNA (neo-mRNA) vaccine delivery and demonstrated its potential for evoking T-cell mediated immune response against drug/radiation resistant glioma cells. Glioblastoma multiforme (GBM) is one of the most aggressive type primary brain tumors with high rate of recurrence and poor prognosis. Temozolomide (TMZ) chemotherapy in concurrence with radiation is less effective for patients with over-expression of DNA repair protein, O6-methyl guanine-DNA methyltransferase (MGMT) or epidermal growth factor receptor variant III (EGFRvIII) mutation. Here, we developed a unique pathogen mimicking nanoparticle platform that can effectively encapsulate and transfect dendritic cells with mRNA vaccine specific to MGMT or EGFRvIII. MGMT/EGFRvIII mRNA was synthesized by in vitro transcription (IVT) from respective cDNA plasmid and 100-150nm sized nanoplex was formed with mRNA at the core with >90% encapsulation efficiency. This Nano-neo-mRNA vaccineTM platform was successfully delivered to human monocyte derived DCs with a transfection efficiency of 35-50% compared to 3-5% in the case of naked mRNA. The transfected DCs showed significant phenotypic expression of MGMT-GFP with MHC I/II and CD80/86 co-activation compared to the naked mRNA or vehicle control. The efficiency of vaccinated DCs to prime cytotoxic T-cells was demonstrated in co-cultures where the nanoplex showed efficient activation of T-cell-mediated cytotoxicity on MGMT or EGFRvIII expressing, TMZ/radiation resistant glioblastoma cells . Biocompatibility of the nano-carrier was demonstrated in primary human cells and animal models. Thus, we present a new, biocompatible nanoparticle platform technology for IVT-mRNA based cancer-immunotherapy.

Citation Format: Manzoor Koyakutty, Navyashree A. Ramesh, Ashwathy Nambiar, Najuma Nujum Ambili Anna, Manju C. Abraham, Minu Anoop, Anjana Ramkumar, Nair Shanti, Vijay Harish Harish, Anusha Ashokan. Nano-neo-mRNA vaccine: A novel platform technology for cancer-immunotherapy [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B116.