A novel therapeutic vaccine based on graphene oxide nanocomposite for tumor immunotherapy

With an intensive understanding of the mechanism of immune system, developing a therapeutic tumor vaccine is one of the most perspective strategy of cancer immunotherapy. In this study, we report a facile approach to prepare graphene oxide (GO)-based therapeutic cancer-nanovaccine. The model antigen (ovalbumin, OVA) and adjuvant (CpG ODN), are conjugated with GO-PEI nanosheet through electrostatic interaction. The addition of PEG can improve biocompatibility and prevent nanoparticle aggregation. The prepared GO-based nanovaccine, GO-PEI-OVA-PEG-CpG, exhibits good biocompatibility and low toxicity both in vivo and in vitro. More importantly, it can efficiently induce the maturation of dendritic cells (DCs), the enhancement of antigen cross-presentation ability, and the amplification of cytokine production of immune cells. Impressively, this nanovaccine shows a remarkable therapeutic effect against pre-established B16-OVA-melanoma tumors, which can significantly inhibit tumor growth and prolong the survival time of the OVA-expressed tumor-bearing mice. Moreover, combining GO-PEI-OVA-PEG-CpG with NLG919, an IDO-1 (indoleamine-2,3-dioxygenase) inhibitor which can regulate the tumor microenvironment, displays a synergistic therapeutic effect. These findings indicate the GO-PEI-OVA-PEG-CpG nanovaccine actively induces an antigen-specific antitumor immune response and it combined with NLG919 could achieve better therapeutic outcomes.