An easily adopted murine model of distal pancreatectomy for investigating immunotherapy efficacy in resectable pancreatic adenocarcinoma

Background: Although surgery provides the greatest therapeutic benefit to eligible pancreatic ductal adenocarcinoma (PDAC) patients it does not significantly improve survival for the majority of patients. Unfortunately our understanding of the therapeutic benefit of combining surgery with different treatment modalities including promising immunotherapeutics is limited by the current lack of easily adopted surgical models. The purpose of this study was to develop a surgically resectable model of PDAC in immunocompetent mice for use in preclinical investigations. Materials and Methods: Surgically resectable orthotopic tumors were generated by injecting Pan02 cells into the tail of the pancreas. Fifteen days post implantation the primary tumors and tail of the pancreas were resected by laparotomy while preserving the spleen. Splenic function, tumor growth, immune phenotyping and survival were assessed following surgical resection of the primary tumor mass. Results: As expected orthotopic tumor implants recapitulated many of the major histological hallmarks of PDAC including disrupted lobular structure and vascular invasion. Preservation of splenic immune cell viability and function was not associated with improved survival following surgery alone. However, pre-operative vaccination with GVAX was associated with improved survival which was not impacted by surgery. Conclusion: This represents the first murine model of surgically resectable murine model of PDAC which recapitulates known pathological hallmarks of human disease in an immune competent model while allowing spleen preservation. This relatively simple and easily adopted approach provides an ideal platform to examine the efficacy of potential immunotherapy combinations for PDAC surgery patients.