Peptide Assemblies as Promising Tumor Vaccines: Current Platforms and Progress

Abstract

Despite many preclinical studies and advantages of the current strategies, some issues are in need of resolution (Table 1). A successful vaccine system must drain to the lymph nodes, capture immune cells, and induce the following immune responses [32, 33]. For self-assembled nanomaterials, it is necessary to understand the fate of self-assembled nanomaterials in vivo and the interactions between assemblies and immune cells. Moreover, current vaccine platforms focus mainly on antigenic epitopes with known amino acid sequences [34]. More effort should be devoted to developing tumor vaccines in situ because of the tumor heterogeneity and the need for personalized tumor vaccines. Currently, no self-assembly peptide-based vaccines are commercially available. The clinical translation remains a challenge owing to the complexity of these building blocks, large-scale manufacturing, and uncontrollable modulation of the immune system. Moreover, the adverse effects and pharmacokinetics (e.g., the timing and dosing of treatment) of self-assembled peptide vaccines need to be carefully examined before advanced clinical trials are launched. We propose several potential developing strategies for future investigation. New methods of prediction and screening of neoantigens, such as next-generation sequencing and data science, will provide a path for successful personalized tumor vaccines. In addition, innovation in vaccine delivery system enables self-assembled peptide vaccines to be spatiotemporally controlled in complex physical environments, thus allowing targeted delivery and reduced adverse effects. Because the chemo- or radio-therapy can cause ICD and enhance the immunogenicity of tumors, the combination of traditional therapy with self-assembled peptide vaccines is expected to augment the immunotherapy efficacy and produce better clinical outcomes. Given the high efficacy of self-assembly peptides and the non-cytotoxic property, we envision that multivalent self-assembled tumor vaccines will be clinically available in the near future.