PT - JOURNAL ARTICLE AU - Hideo Kohka Takahashi AU - Takeshi Watanabe AU - Akira Yokoyama AU - Hiromi Iwagaki AU - Tadashi Yoshino AU - Noriaki Tanaka AU - Masahiro Nishibori TI - Cimetidine Induces Interleukin-18 Production through H2-Agonist Activity in Monocytes AID - 10.1124/mol.106.025890 DP - 2006 Aug 01 TA - Molecular Pharmacology PG - 450--453 VI - 70 IP - 2 4099 - http://molpharm.aspetjournals.org/content/70/2/450.short 4100 - http://molpharm.aspetjournals.org/content/70/2/450.full SO - Mol Pharmacol2006 Aug 01; 70 AB - The present study demonstrates a possible mechanism for the improvement of gastrointestinal cancer patients' prognosis by the histamine receptor type 2 (H2R) antagonist cimetidine. This agent, but not the H2R antagonists ranitidine and famotidine, induced the production of an antitumor cytokine, interleukin (IL)-18, by human monocytes and dendritic cells (DC). In fact, ranitidine and famotidine antagonized cimetidine-induced IL-18 production. Cimetidine induced the activation of caspase-1, which is reported to modify immature IL-18 to mature/active IL-18, and the elevation of intracellular cAMP, leading to the activation of protein kinase A (PKA). The PKA inhibitor H89 abolished the IL-18 production induced by cimetidine. Moreover, the effects of cimetidine on IL-18 production were reproduced in peripheral blood mononuclear cells from wild-type mice, but not in those from H2R knockout mice. In conclusion, cimetidine, a partial agonist for H2R, has a pharmacological profile different from ranitidine and famotidine, possibly contributing to its antitumor activity on gastrointestinal cancers.