Fe2P nanorods based photothermal therapy combined with immune checkpoint inhibitors for pancreatic cancer

Abstract

Abstract Treatment of pancreatic cancer is faced with great difficulties and challenges due to high lethality and metastasis. Synergism of targeted therapy and immunotherapy has been considered as ideal strategy to both eliminate primary tumors and control metastases. For the treatment of advanced pancreatic cancer, we demonstrated a local photothermal therapy (PTT) following administration of monoclonal antibody of programmed death ligand 1 (αPD-L1). Fe2P nanorods were employed as a Fenton agent and photothermal agent, which modified with DSPE-PEG2000-Mal for improved biocompatibility and Mal mediated-antigen presentation. Under a low dose laser irradiation at 980 nm, Fe2P-PEG-Mal nanorods (NRs) mediated PTT could induce immunogenic tumor cell death that can cause dendritic cells (DCs) infiltration and maturation. In a bilateral pancreatic tumor model, the local treatment of NRs-PTT on primary tumor could cause the increased infiltration of cytotoxic T lymphocytes (CTLs) and decreased residential of M2 macrophages in untreated distal tumors. Furthermore, subsequently intervened αPD-L1 could enhance cell death triggered by CTLs in distal tumors through reversing immunosuppression. An orthotopic pancreatic tumor model was used to further confirm the therapeutic outcome. Finally, the combination of NRs based PTT and αPD-L1 based immunotherapy was able to significantly eliminate orthotopic pancreatic tumors and reduce mesentery metastases. Thus, the strategy may provide a more effective treatment for pancreatic cancer.