Nanoliposomal VEGF-R2 peptide vaccine acts as an effective therapeutic vaccine in a murine B16F10 model of melanoma

Background: The vascular endothelial growth factor receptor-2 (VEGFR-2) plays an important role in melanoma development and progression. Peptide vaccines have shown great potential in cancer immunotherapy by targeting VEGFR-2 as a tumor-associated antigen and boosting the immune response against both tumor cells and tumor endothelial cells. Despite this, the low efficiency of peptide vaccines has resulted in moderate therapeutic results in the majority of studies. Enhancing the delivery of peptide vaccines using nanoliposomes is an important strategy for improving the efficacy of peptide vaccines. In this regard, we designed VEGFR-2-derived peptides restricted to both mouse MHC I and human HLA-A*02:01 using immunoinformatic tools and selected three peptides representing the highest binding affinities. The peptides were encapsulated in nanoliposomal formulations using the film method plus bath sonication and characterized for their colloidal properties. Results: The mean diameter of peptide-encapsulated liposomes was around 135 nm, zeta potential of - 17 mV, and encapsulation efficiency of approximately 70%. Then, vaccine formulations were injected subcutaneously in mice bearing B16F10-established melanoma tumors and their efficiency in triggering immunological, and anti-tumor responses was evaluated. Our results represented that one of our designed VEGFR-2 peptide nanoliposomal formulations (Lip-V1) substantially activated CD4(+) (p < 0.0001) and CD8(+) (P < 0.001) T cell responses and significantly boosted the production of IFN-gamma (P < 0.0001) and IL-4 (P < 0.0001). Furthermore, this formulation led to a significant decrease in tumor volume (P < 0.0001) and enhanced survival (P < 0.05) in mice. Conclusion: Our findings suggest that the nanoliposomal formulation containing VEGFR-2 peptides could be a promising therapeutic vaccination approach capable of eliciting strong antigen-specific immunologic and anti-tumor responses.

Automated summary

This study aimed to enhance the efficiency of peptide vaccines by using nanoliposomes. VEGFR-2-derived peptides were encapsulated in nanoliposomal formulations and injected into mice with melanoma tumors. The results showed that the nanoliposomal formulation effectively triggered immune responses, inhibited tumor growth, and improved survival rates.