Adenoviral-Based Immunotherapy Provides Local Disease Control in an Orthotopic Murine Model of Esophageal Cancer

Despite recent advances in the development of novel therapies, esophageal carcinoma remains an aggressive cancer associated with a poor prognosis. The lack a high throughput, reproducible syngeneic animal model that replicates human disease is partly responsible for the paucity of novel therapeutic approaches. In this report, we present the first successful syngeneic, orthotopic model for esophageal cancer. This model was used to test an established adenoviral-based tumor vaccine. We utilized a murine esophageal cancer cell line established from the EDL2-cyclin D1;p53−/− mouse that was transduced to express a viral tumor antigen, the Human Papilloma Virus (HPV) E7 protein. The tumor was established in its natural microenvironment at the gastroesophageal (GE) junction. Tumor growth was consistent and reproducible. An adenoviral vaccine to E7 (Ad.E7) induced an E7-specific population of functionally active CD8+ T cells which trafficked into the tumors and retained cytotoxicity. Ad.E7 vaccination reduced local tumor growth and prolonged overall survival. These findings suggest that orthotopic tumor growth is a reasonable preclinical model to validate novel therapies.