Mannose-modified liposome designed for epitope peptide drug delivery in cancer immunotherapy.

BACKGROUND: Based on the interaction between cytotoxic T lymphocyte (CTL) dominant epitopes and dendritic cells (DCs), CD8+T cells are specifically activated into CTL cells. Targeted killing is a type of tumor vaccine for immunotherapy with great development potential. However, because of the disadvantages of poor stability in vivo and low uptake rate of DCs caused by single use of dominant epitope peptide drugs, its use is limited. Here, we investigated the antitumor potential of M-YL/LA-Lipo, a novel liposome drug delivery system. METHODS: We assembled mannose on the surface of liposome, which has a highly targeted effect on the mannose receptor on the surface of DCs. The dominant epitope peptide drugs were encapsulated into the liposome using membrane hydration method, and the encapsulation rate, release rate, in vitro stability, and microstructure were characterized using ultrafiltration method, dialysis method, and negative staining transmission electron microscopy. In addition, its targeting ability was verified by in vitro interaction with DCs, and its anticancer effect was verified by animal experiments. RESULTS: We have successfully prepared a liposome drug delivery system with stable physical and chemical properties. Moreover, we demonstrated that it was highly uptaken by DCs and promoted DC maturation in vitro. Furthermore, in vivo animal experiments indicated that M-YL/LA-Lipo specific CTL significantly inhibited the hematogenous spread of lung metastasis of triple negative breast cancer. CONCLUSIONS: we successfully constructed a new polypeptide liposome drug delivery system by avoiding the disadvantages of single use of dominant epitope peptide drugs and accurate targeted therapy for tumors.

HLA-A2.1-restricted ECM1-derived epitope LA through DC cross-activation priming CD8+ T and NK cells: a novel therapeutic tumour vaccine.

BACKGROUND: CD8+ T cell-mediated adaptive cellular immunity and natural killer (NK) cell-mediated innate immunity both play important roles in tumour immunity. This study aimed to develop therapeutic tumour vaccines based on double-activation of CD8+ T and NK cells. METHODS: The immune Epitope database, Molecular Operating Environment software, and enzyme-linked immunosorbent assay were used for epitope identification. Flow cytometry, confocal microscopy, UPLC-QTOF-MS, and RNA-seq were utilized for evaluating immunity of PBMC-derived DCs, CD8+ T or NK cells and related pathways. HLA-A2.1 transgenic mice combined with immunologically reconstituted tumour-bearing mice were used to examine the antitumour effect and safety of epitope vaccines. RESULTS: We identified novel HLA-A2.1-restricted extracellular matrix protein 1(ECM1)-derived immunodominant epitopes in which LA induced a potent immune response. We also found that LA-loaded DCs upregulated the frequency of CD3+/CD8+ T cells, CD45RO+/CD69+ activated memory T cells, and CD3-/CD16+/CD56+ NK cells. We demonstrated cytotoxic granule release of LA/DC-CTLs or LA/DC-NK cells and cytotoxicity against tumour cells and microtissue blocks via the predominant IFN-γ/perforin/granzyme B cell death pathway. Further investigating the mechanism of LA-mediated CD8+ T activation, we found that LA could be internalized into DCs through phagocytosis and then formed a LA-MHC-I complex presented onto the DC surface for recognition of the T cell receptor to upregulate Zap70 phosphorylation levels to further activate CD8+ T cells by DC-CTL interactions. In addition, LA-mediated DC-NK crosstalk through stimulation of the TLR4-p38 MAPK pathway increased MICA/B expression on DCs to interact with NKG2D for NK activation. Promisingly, LA could activate CD8+ T cells and NK cells simultaneously via interacting with DCs to suppress tumours in vivo. Moreover, the safety of LA was confirmed. CONCLUSIONS: LA-induced immune antitumour activity through DC cross-activation with CD8+ T and NK cells, which demonstrated proof-of-concept evidence for the capability and safety of a novel therapeutic tumour vaccine.