A lipid-based LMP2-mRNA vaccine to treat nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a serious and highly invasive epithelial malignancy that is closely associated with Epstein‒Barr virus (EBV). Due to the lack of therapeutic vaccines for NPC, we selected EBV latent membrane protein 2 (LMP2) as a preferable targeting antigen to develop a lipid-based LMP2-mRNA (mLMP2) vaccine. Full-length mLMP2 expressing LMP2 was first synthesized using an in vitro transcription method and then encapsulated into (2,3-dioleacyl propyl) trimethylammonium chloride (DOTAP)-based cationic liposomes to obtain the mRNA vaccine (LPX-mLMP2). The cell assays showed that the antigen-presenting cells were capable of highly efficient uptake of LPX-mLMP2 and expression of LMP2. LMP2 could subsequently be presented to form the peptide-major histocompatibility complex (pMHC). Furthermore, LPX-mLMP2 could accumulate in the spleen, express antigens, promote the maturation of dendritic cells and stimulate antigen-specific T-cell responses in vivo. It dramatically inhibited the tumor growth of the LMP2-expressing tumor model after three doses of vaccination. Additionally, the proliferation of antigen-specific T cells in the tumor site made a good sign for the promise of mRNA vaccines in virus-induced cancer. Overall, we provided a newly developed antigen-encoding mRNA vaccine with advantages against NPC. We also demonstrated that mRNA vaccines are attractive candidates for cancer immunotherapy.