Pancreatic cancer is both difficult to detect and harbors survival rates as low as 5%, thus heightening the need for better and new therapies. Several molecules have been investigated to increase the immunogenicity of tumor cells including the costimulatory molecule B7-1. The murine pancreatic cancer cell line, Pan02, expresses low, endogenous levels of B7-1; however, the role of B7-1 in pancreatic cancer progression has not yet been elucidated. We hypothesized that increased cell surface expression of B7-1 in the Pan02 model would decrease tumor growth and metastasis. To test this, Pan02 cells were transfected with mB7-1 (Pan02-mB7-1). Flow cytometry analysis confirmed a 40-fold increase in B7-1 cell surface expression in transfected cells compared to WT. In order to assess the in vivo effects of increased B7-1 expression, C57BL/6 mice, were challenged with Pan02-mB7-1 and Pan02-WT cells. We observed that B7-1 transfected Pan02 cells showed an overall decrease in tumor kinetics compared to mice challenged with Pan02-WT. In addition, increased cell surface B7-1 expression prevented metastasis to the lung in tumor positive C57BL-6 mice. More interestingly, Pan02 cells that metastasized to the lung (Pan02-RG-M-Lung) from WT challenged mice showed lower B7-1 expression by flow cytometry compared to Pan02-WT cells. Taken together, increased cell surface B7-1 expression is successful in inhibiting tumor growth and preventing metastasis in the murine pancreatic cancer model.
- Copyright © 2013 by The American Association of Immunologists, Inc.