Listeria delivers tetanus toxoid protein to pancreatic tumors and induces cancer cell death in mice

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is a highly metastatic disease. Tumors are poorly immunogenic and immunosuppressive, preventing T cell activation in the tumor microenvironment. Here, we present a microbial-based immunotherapeutic treatment for selective delivery of an immunogenic tetanus toxoid protein (TT 856-1313 ) into PDAC tumor cells by attenuated Listeria monocytogenes . This treatment reactivated preexisting TT-specific memory T cells to kill infected tumor cells in mice. Treatment of KrasG12D,p53R172H, Pdx1-Cre (KPC) mice with Listeria -TT resulted in TT accumulation inside tumor cells, attraction of TT-specific memory CD4 T cells to the tumor microenvironment, and production of perforin and granzyme B in tumors. Low doses of gemcitabine (GEM) increased immune effects of Listeria -TT, turning immunologically cold into hot tumors in mice. In vivo depletion of T cells from Listeria -TT + GEM–treated mice demonstrated a CD4 T cell–mediated reduction in tumor burden. CD4 T cells from TT-vaccinated mice were able to kill TT-expressing Panc-02 tumor cells in vitro. In addition, peritumoral lymph node–like structures were observed in close contact with pancreatic tumors in KPC mice treated with Listeria -TT or Listeria -TT + GEM. These structures displayed CD4 and CD8 T cells producing perforin and granzyme B. Whereas CD4 T cells efficiently infiltrated the KPC tumors, CD8 T cells did not. Listeria -TT + GEM treatment of KPC mice with advanced PDAC reduced tumor burden by 80% and metastases by 87% after treatment and increased survival by 40% compared to nontreated mice. These results suggest that Listeria -delivered recall antigens could be an alternative to neoantigen-mediated cancer immunotherapy.

The Role of Metabolic Plasticity of Tumor-Associated Macrophages in Shaping the Tumor Microenvironment Immunity

“…A recent report by Selvanesan et al showed that gemcitabine (GEM) in combination with immunotherapy altered the immunosuppressive TME in a mouse model of PDAC. GEM, which showed to increase ROS production, when combined with the tetanus toxin, decreased the immunosuppression of the PDAC tumor by decreasing the MDSC, and Trges while increasing the CD4 + T cells [ 123 ].…”

Genetically engineered bacterium: Principles, practices, and prospects

“…Notably, E. coli ( Michael Schultz, 2008 ; He et al, 2017 ; Christofi et al, 2019 ; Terol et al, 2021 ), Lactobacillus ( Yang et al, 2015 ; Lin et al, 2016 ; Chen et al, 2017 ; Oh et al, 2020 ), Salmonella ( Chirullo et al, 2015 ; Zheng and Min, 2016 ; Li et al, 2017 ; Lim et al, 2017 ; Kawaguchi et al, 2018 ) are the most popular bacteria used as chassis tools for constructing different GEBs. In particular, more than 50 bacterial species, such as Bifidobacterium ( Liu et al, 2018 ), Bacillus subtilis ( Westbrook et al, 2016 ), Listeria monocytogenes ( Selvanesan et al, 2022 ), and Lactobacillus brevis CD2 ( He et al, 2017 ; Alfano et al, 2020 ), are being used in health care and scientific research ( Figure 1 ).…”

Current Status and Future Directions of Bacteria-Based Immunotherapy

“…To reform the poorly immunogenic TME of pancreatic ductal adenocarcinoma, Gravekamp et al delivered tetanus toxoid protein, which act as a neoantigen reactivating preexisting memory T cells that were generated during childhood vaccinations, into tumor cells by attenuated Listeria, which could selectively delivered to tumor regions with the help of MDSCs (53). The tetanus toxoid induced attraction of CD4 T cells, with increased production of IFNg, perforin, and granzyme B in the TME, while gemcitabine was used to reduce immune suppression in the TME, which resulted in reduced tumor burden by 80% compared to untreated mice (95).…”

“…For certain cancer type with low immunogenicity and low expression of neoantigen such as pancreatic ductal adenocarcinoma, Gravekamp et al has designed a platform to deliver the immunogenic tetanus toxoid protein by L. monocytogenes. In this method, the tetanus toxoid acted as an alternative neoantigen to awaken the preexisting memory T cells generated in childhood vaccination, thus turning the cold TME into a highly immunological environment, which eventually resulted in over 80% reduction of tumor growth and metastasis when coupled with the treatment of gemcitabine (95).…”