RT Journal Article SR Electronic T1 Pharmacology and Antitumor Activity of ABC294640, a Selective Inhibitor of Sphingosine Kinase-2 JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 129 OP 139 DO 10.1124/jpet.109.163444 VO 333 IS 1 A1 Kevin J. French A1 Yan Zhuang A1 Lynn W. Maines A1 Peng Gao A1 Wenxue Wang A1 Vladimir Beljanski A1 John J. Upson A1 Cecelia L. Green A1 Staci N. Keller A1 Charles D. Smith YR 2010 UL http://jpet.aspetjournals.org/content/333/1/129.abstract AB Sphingolipid-metabolizing enzymes control the dynamic balance of the cellular levels of important bioactive lipids, including the apoptotic compound ceramide and the proliferative compound sphingosine 1-phosphate (S1P). Many growth factors and inflammatory cytokines promote the cleavage of sphingomyelin and ceramide leading to rapid elevation of S1P levels through the action of sphingosine kinases (SK1 and SK2). SK1 and SK2 are overexpressed in a variety of human cancers, making these enzymes potential molecular targets for cancer therapy. We have identified an aryladamantane compound, termed ABC294640 [3-(4-chlorophenyl)-adamantane-1-carboxylic acid (pyridin-4-ylmethyl)amide], that selectively inhibits SK2 activity in vitro, acting as a competitive inhibitor with respect to sphingosine with a Ki of 9.8 μM, and attenuates S1P formation in intact cells. In tissue culture, ABC294640 suppresses the proliferation of a broad panel of tumor cell lines, and inhibits tumor cell migration concomitant with loss of microfilaments. In vivo, ABC294640 has excellent oral bioavailability, and demonstrates a plasma clearance half-time of 4.5 h in mice. Acute and chronic toxicology studies indicate that ABC294640 induces a transient minor decrease in the hematocrit of rats and mice; however, this normalizes by 28 days of treatment. No other changes in hematology parameters, or gross or microscopic tissue pathology, result from treatment with ABC294640. Oral administration of ABC294640 to mice bearing mammary adenocarcinoma xenografts results in dose-dependent antitumor activity associated with depletion of S1P levels in the tumors and progressive tumor cell apoptosis. Therefore, this newly developed SK2 inhibitor provides an orally available drug candidate for the treatment of cancer and other diseases.