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Pancreatic cancer is characterized is an aggressive malignant with a marked resistance to conventional therapies and to apoptotic activators. The lack/failure of response to apoptosis induction leads to the development and rapid progression of tumors. Thus, induction of apoptosis in pancreatic tumor cells is an effective approach to the regulation of pancreatic tumor growth. Identification of successful therapeutic strategies involving compounds alone or in combination with synergistic or additive action, guides the development of novel agents for pancreatic cancer prevention and treatment. Thus, experiments were designed to assess the effect of curcumin and decosahexaenoic acid (DHA), individually and in combination on human pancreatic cancer cell line BxPC-3, which over-express cyclooxygenase-2 (COX-2) and 5-lipoxyganse (5-LOX). We demonstrated the levels of induction of apoptosis (flow-cytometry, DNA fragmentation and DAPI method), proliferation (β-hexosaminidase assay), COX-2, 5-LOX, Bcl-2, Bax expressions (Western Blot analysis), and caspase-3 activity (fluorimetric method) with various subtoxic concentrations of curcumin, DHA, or combinations of both in BxPC-3 cells. We found that treatment with curcumin (5-20µM) or DHA (25-100µM) induces apoptosis and inhibits cell proliferation significantly only at high concentrations in BxPC-3 cells. Importantly, a synergistic effect was observed on induction of apoptosis (~6 fold) and inhibition of cell proliferation (~70%) when cells were treated to low doses of curcumin (5-10µM) together with the DHA (25-50µM). Further, treatment of BxPC-3 cells with curcumin (10 µM) and DHA (50 µM) inhibited COX-2 (53% and 32% respectively) and 5-LOX (48% and 25% respectively), and a combination of both at 5 µM curcumin and 25 µM DHA significantly suppressed COX-2 (85%) and 5-LOX (81%) expression levels. Similarly, treatment with low doses of curcumin plus DHA resulted in significant down regulation of Bcl-2 and up regulation of Bax expression levels than with individual agents at high concentrations. We also observed an increased level of caspase-3 activity in higher doses of curcumin and DHA. Importantly, a significant increase in caspase-3 activity (~5-fold) was observed with a combination of curcumin plus DHA at low dose levels. These findings provide the basis for the further development of new combinations using regimens of curcumin and DHA for the prevention and treatment of pancreatic cancer. (Supported in part by Kerley-Cade Endowed Chair Funds).

98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA