Effect of prostaglandin E2 on the proliferation, Ca2+ mobilization and cAMP in HT-29 human colon adenocarcinoma cells

Several lines of evidence suggest that non-steroidal antiinflammatory drugs (NSAIDs) have anticarcinogenic effects. The causal relationship linking the preventive effect of NSAIDs on colon cancer and the inhibition of prostaglandin synthesis is questioned by the contrasting results obtained by many laboratories. The experiments reported in this paper demonstrate that prostaglandin E2 (PGE2) did not stimulate the proliferation in HT-29 human colon adenocarcinoma cells under several experimental conditions. Moreover, PGE2 and 17-phenyl trinor prostaglandin E2 (a specific agonist of EP1 receptors) did not increase intracellular Ca2+ concentration. Finally, PGE2 did not affect the intracellular cAMP and did not reduce the isoproterenol dependent increase in cAMP. These results indicate that in HT-29 cells: (1) proliferation is not directly sensitive to PGE2; and (2) PGE2 does not stimulate a signal transduction pathway leading to intracellular increase in cAMP or Ca2+ mobilization. Therefore, other cell lines should be used to assess the direct role played by prostanoids in promoting cell proliferation in colon cancer.