The objective of this project is to study the mechanism-based chemoprevention of pancreatic carcinogenesis by HMG-CoA reductase inhibitor Lipitor and its combination with polyphenol E (a standardized tea polyphenol preparation). Our central hypothesis is that the inhibition of K-ras oncogene-driven pancreatic carcinogenesis by Lipitor is through targeting the mevalonate metabolic pathway, in particular via inhibiting prenylation and dolichylation on k-ras, lamins and IGF-1R proteins; the synergistic or additive effects on prevention of pancreatic carcinogenesis by the combination of Lipitor and polyphenol E will be produced through inhibition of arachidonic acid metabolits and down-stream signals of the K-ras pathway (such as ErK1/2 and c-Jun protein phosphorylation). We will test this hypothesis using a genetically engineered mouse model of pancreatic cancer (compound endogenously and conditionally knocked-in mouse model: LSL-k- rasG12D/?Trigh doses, and combination with low dose, of each agent) to test whether the combination of agents produces synergistic or additive effects, in addition to the inhibitory effect of each agent on pancreatic carcinogenesis. 2. Test the hypothesis that targeting the mevalonate pathway, arachidonic acid metabolits, and K-ras downstream signals by the combination of Lipitor and polyphenol E are the key molecular mechanisms in the prevention of pancreatic carcinogenesis. The specimens generated from Specific Aim 1 will be further examined for activity of k-ras protein, Ras, and IGF-1R protein membranous bound, and k-ras downstream signals, lamin and arachidonic acid metabolites with the biochemical and immunochemical approaches to reveal the mechanism involved. Furthermore, in-depth mechanistic studies will be performed using the selected immortalized human pancreatic ductal epithelial cell line and its k-ras transformed cell line in vitro. Using a genetically engineered mouse model of molecular-mimic pancreas cancer combined with chemopreventive agents, this project will be significant in the development of efficient strategy for the prevention of pancreas cancer in human. ? ? ? ????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
