Genetically-engineered“all-in-one”vaccine platform for cancer immunotherapy

An essential step for cancer vaccination is to break the immunosuppression and elicit a tumor-specific immunity.A major hurdle against cancer therapeutic vaccination is the insufficient immune stimulation of the cancer vaccines and lack of a safe and efficient adjuvant for human use.We discovered a novel cancer immunostimulant,trichosanthin(TCS),that is a clinically used protein drug in China,and developed a well-adaptable protein-engineering method for making recombinant protein vaccines by fusion of an antigenic peptide,TCS,and a cell-penetrating peptide(CPP),termed an"allin-one"vaccine,for transcutaneous cancer immunization.The TCS adjuvant effect on antigen presentation was investigated and the antitumor immunity of the vaccines was investigated using the different tumor models.The vaccines were prepared via a facile recombinant method.The vaccines induced the maturation of DCs that subsequently primed CD8^(+)T cells.The TCS-based immunostimulation was associated with the STING pathway.The general applicability of this genetic engineering strategy was demonstrated with various tumor antigens(i.e.,legumain and TRP2 antigenic peptides)and tumor models(i.e.,colon tumor and melanoma).These findings represent a useful protocol for developing cancer vaccines at low cost and time-saving,and demonstrates the adjuvant application of TCSdan old drug for a new application.

Transdermal delivery of interleukin-12 gene targeting dendritic cells enhances the anti-tumour effect of programmed cell death protein 1 monoclonal antibody

Recent studies have suggested that the anti-tumour effect of the programmed cell death protein 1 monoclonal antibody(aPD-1)depends on the expression of interleukin-12(IL-12)by dendritic cells(DCs).Since DCs are abundant in skin tissues,transdermal delivery of IL-12 targeting DCs may significantly improve the anti-tumour effect of aPD-1.In this study,a novel mannosylated chitosan(MC)-modified ethosome(Eth-MC)was obtained through electrostatic adsorption.The Eth-MC loaded with plasmid containing the IL-12 gene(pIL-12@Eth-MC)stimulated DCs to express mature-related molecular markers such as CD86,CD80,and major histocompatibility complex-II in a targeted manner.The pIL-12@Eth-MC was then mixed with polyvinyl pyrrolidone solution to make microspheres using the electrospray technique,and sprayed onto the surface of electrospun silk fibroin-polyvinyl alcohol nanofibres to obtain a PVP-pIL-12@Eth-MC/silk fibroin-polyvinyl alcohol composite nanofibrous patch(termed a transcutaneous immunization(TCI)patch).The TCI patch showed a good performance on transdermal drug release.Animal experiments on melanoma-bearing mice showed that topical application of the TCI patches promoted the expression of IL-12 and inhibited the growth of tumour.Furthermore,combined application of the TCI patch and aPD-1 showed a stronger anti-tumour effect than aPD-1 monotherapy.The combination therapy significantly promoted the expression of IL-12,interferon-γand tumour necrosis factor-α,the infiltration of CD4+and CD8+T cells into tumour tissues,and thus promoted the apoptosis of tumour cells.The present study provides a convenient and non-invasive strategy for improving the efficacy of immune checkpoint inhibitor therapy.This study was approved by the Institutional Animal Care and Use Committee at Donghua University(approval No.DHUEC-NSFC-2020-11)on March 31,2020.