Project 4

Targeting Metabolic Alterations to Improve Survival in Pancreatic Cancer

Project Leaders:  Pankaj Singh, PhD and Jean Grem, MD

Poor prognosis in pancreatic cancer is due in part to poor response to the current standard of care (gemcitabine, a cytidine nucleoside analog). Our preliminary data establish a novel, widely-prevalent mechanism of resistance to fluoropyrimidines whereby the Hypoxia-Inducible Factor1 (HIF1) alpha-induced glycolytic flux leads to a corresponding increase in the pyrimidine biosynthetic pathway to enhance the intrinsic levels of cytidine. Such increased levels of cytidine/dCTP diminish the effective levels of gemcitabine and 5FU (in FOLFIRINOX) through molecular competition or dilution. Our data also indicate existence of a bidirectional tumor-stromal metabolite flux that may facilitate tumor/stromal cell survival under low nutrient conditions, promote desmoplasia, increase metabolite flux into pyrimidine biosynthetic pathway, and result in decreased chemotherapy sensitivity. Thus, we proposed to determine if combining gemcitabine/FOLFIRINOX therapies with digoxin (to target HIF1 alpha) or Leflunomide (to target pyrimidine biosynthesis) would diminish fluoropyrimidine therapy resistance in pancreatic cancer patients (AIM 1). Additionally, we employed 18FFDG-PET imaging in pancreatic cancer patients to predict the resistance status of the tumor against pyrimidine analogs (AIM1). We also investigated if cytidine levels in pancreatic tumors/biofluids could serve as potential biomarkers for chemotherapy responsiveness in pancreatic cancer patients (AIM2).