Exosomes derived from immunogenically dying tumor cells as a versatile tool for vaccination against pancreatic cancer

Despite tremendous progress achieved in immunotherapy, many critical challenges in treating pancreatic ductal adenocarcinoma (PDAC) persist. Considering the poor vascularization of PDAC, after intramuscular adminis-tration exosomes can targeted deliver cargos to pancreatic tumors and bypass obstructions of the intrinsic overexpressed stroma through lymphatics. Herein, we propose a strategy to derive exosomes from immuno-genically dying tumor cells and exploit their properties for several purposes, including antigen presentation, adjuvant supply, and cargo delivery of vaccines against pancreatic cancer via intramuscular injection. To enhance the immunostimulatory effects, the MART-1 peptide is modified to the exosomes to expand T-cell-related responses. Furthermore, CCL22 siRNA is electroporated into the exosomes (referred to as spMEXO) to hinder the CCR4/CCL22 axis between DCs and Tregs, thereby suppressing Treg expansion. Both in vitro and in vivo studies demonstrate that spMEXO can serve as an effective prophylactic vaccine to delay tumor growth, whereas combining spMEXO with PDAC first-line chemotherapeutics (co-administration of gemcitabine with albumin-paclitaxel) demonstrated significantly enhanced therapeutic effects in established PANC-02 tumors. Therefore, the present work provides an effective strategy to employ cancer vaccines through intramuscular injection in PDAC and highlights the potential of exosomes derived from immunogenically dying tumor cells as a versatile tool to develop nanovaccines for immunotherapy.

Automated summary

This study proposes a strategy to derive exosomes from immunogenically dying tumor cells and utilize them for various purposes, including antigen presentation and cargo delivery of vaccines against pancreatic cancer. The results demonstrate that these exosomes can serve as an effective prophylactic vaccine and combining them with chemotherapy can enhance therapeutic effects.