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

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related death. Low response rate, acquired resistance, immunosuppressive microenvironment, and severe side-effects have limited the clinical outcomes of immunotherapy in 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 cell stimulation despite their expression of tumor-associated antigens (TAA). Trp53R172H is among the most common TP53 mutations in human PDAC, and is known to be one of its TAA. To that end, we designed DC-targeted nanoparticles (NP) containing PDAC Trp53R172H TAA and immune potentiators to enhance the antigen presentation on DC, thus promote specific activation of T cells against the specific antigen of interest. These NP were formulated by double emulsion (w/o/w) method and loaded with PDAC’s TAA and immune potentiators, such as Toll-like receptors (TLR) agonists. The quantification of Trp53R172H TAA, performed by fluorescamine, revealed 70% encapsulation efficiency. DC targeting moiety, mannose, was covalently conjugated to the NP. Full characterization of the NP’s physico-chemical properties was done using dynamic light scattering, zeta potential and scanning electron microscopy to determine the mean average size, surface charge, and morphology. In addition, biodistribution profile of the NP was evaluated intravitally non-invasively, which demonstrated that fluorescent(Cy5)-labeled NP were selectively accumulated in the lymph nodes. The therapeutic activity of the NP was evaluated by our unique 3D multi-cellular PDAC spheroid model, composed of freshly-isolated murine cancer and stromal cells, which better mimic the clinical scenario. Moreover, our NP were able to activate splenocytes and induce cytotoxicity against PDAC cells ex-vivo. Along with an in-vivo PDAC model, we assessed the NP’s safety profile and efficacy. Evaluation of DC-related co-stimulatory molecules such as CD80, CD86, and CD40 revealed DC activation. Taken together, we expect that the NP proposed herein will elicit a specific immune reaction against PDAC, resulting in safe and prolonged survival rate.