Epidemiologic and animal studies have linked
pancreatic cancer growth with fat intake, especially
unsaturated fats.
Arachidonic acid release from membrane
phospholipids is essential for
tumor cell proliferation.
Lipoxygenases (LOX) constitute one pathway for arachidonate metabolism. We previously reported that 5-LOX and 12-LOX are upregulated in human
pancreatic cancer cells and that blockade of these
enzymes abolishes
pancreatic cancer cell growth. The present study was aimed at evaluating the effect of LOX inhibition on differentiation and apoptosis in
pancreatic cancer cells in parallel with growth inhibition. Four human
pancreatic cancer cell lines, PANC-1, MiaPaca2, Capan2, and HPAF, were used. Apoptosis was evaluated by three separate methods, including
DNA propidium iodide staining, DNA fragmentation, and the TUNEL assay. Morphological changes and
carbonic anhydrase activity were used to determine the effect of LOX inhibitors on differentiation. The general LOX inhibitor NDGA, the 5-LOX inhibitor Rev5901, and the 12-LOX inhibitor
baicalein all induced apoptosis in all four
pancreatic cancer cell lines, as confirmed by all three methods, suggesting that both the 5-LOX and 12-LOX pathways are important for survival of these cells. Furthermore, NDGA, Rev5901, or
baicalein resulted in marked cellular morphological changes in parallel with increased intracellular
carbonic anhydrase activity, indicating that LOX blockade induced a more differentiated phenotype in human
pancreatic cancer cells. Together with our previous findings, this study suggests that perturbations of LOX activity affect
pancreatic cancer cell proliferation and survival. Blockade of LOX
enzymes may be valuable for the treatment of human
pancreatic cancer.