Designing a dendritic cell-targeted immunotherapy for the treatment of pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related death. Low response rate, acquired resistance, severe side effects, highly desmoplastic and immunosuppressive microenvironment have limited the clinical outcomes of immunotherapy in PDAC. To overcome these hurdles, we set to design a novel immunotherapy that would be safe, efficacious, and selective to PDAC. The failure of immunotherapies to yield clinical response in PDAC is partially attributed to the inefficient antigen presentation by dendritic cells (DC) which results in insufficient T cells stimulation despite their expression of tumor-associated antigens (TAA). DC have an important role in the initiation and regulation of the innate and adaptive arms of the immune system. By efficient presentation of antigens, DC elicit an antigen-specific immune response. Trp53R172H is among the most common TP53 mutations in human PDAC, and is known as one of PDAC TAA. Despite the poor clinical outcomes, longer survival time was observed in PDAC patients with tumors that express high number of TAA combined with an abundant presentation of CD8+ T cell. To that end, we designed a DC-targeted nanoparticle (NP) containing PDAC Trp53R172H TAA and immune potentiators, with the DC targeting moiety, mannose, that was covalently conjugated to the NP, to enhance TAA presentation on DC. This approach led to specific activation of T cells against PDAC's TAA. The therapeutic activity of the NP was evaluated in vitro by our newly established 3D PDAC spheroids model, which is composed of freshly isolated murine stromal cells, therefore, better imitates the complex microenvironment found in PDAC. Along with an in vivo PDAC model, we evaluated the safety profile and therapeutic efficacy of our NP. The NP proposed herein successfully activated splenocytes and induced a specific cytotoxic reaction against PDAC cells ex vivo, which may result in improved survival rate. Citation Format: Ron Kleiner, Daniella Vaskovich, Sabina Pozzi, Anat Eldar-Boock, Dikla Ben-Shushan, Helena Florindo, Ronit Satchi-Fainaro. Designing a dendritic cell-targeted immunotherapy for the treatment of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1746.