Preclinical immunotherapy studies using an orthotopic pancreatic cancer mouse model.

Abstract

324 Background: Pancreatic cancer is well known for its aggressive clinical course and resistance to chemotherapy. The advent of new mouse models of pancreatic cancer have accelerated our understanding of tumorigenesis and enabled preclinical testing of experimental therapeutics with a desire to translate these findings into meaningful clinical treatments. Methods: We have developed a model where pancreatic cells obtained from a KrasG12D;Trp53R172H genetically engineered mouse can be cultivated in two dimensional cell culture and implanted into the pancreas of a immunocompetent syngeneic mouse allowing for tumor formation in situ. In addition, we are using this model to study the effectiveness of new drug combination therapy such as gemcitabine, albumin-bound paclitaxel and CD40 agonist immunotherapy using overall survival as a primary endpoint. Results: These cells generate tumors of five millimeter diameter within two weeks of implantation with 100% efficiency. Because cancer cells are seeded in the context of normal surrounding pancreatic tissue, this model is not hampered by the genetic field effect of expressing cancer mutations in the entire pancreatic organ, allowing for the study of the tumor microenviroment. Responses to therapeutic interventions can be non-invasively monitored through small animal high resolution ultrasound. Conclusions: Our orthotopic pancreatic cancer mouse system is an effective model for pre-clinical studies of tumorigenesis, immunotherapy and examination of the tumor microenvironment. Future experiments will focus on exploiting this system for identifying potent immunotherapy and chemotherapy combinations and for detecting biomarkers of efficiency.