%0 Journal Article
%T The Roles of Sphingosine Kinase 1 and 2 in Regulating the Metabolome and Survival of Prostate Cancer Cells
%A Francesca Tonelli
%A Manal Alossaimi
%A Viswanathan Natarajan
%A Irina Gorshkova
%A Evgeny Berdyshev
%A Robert Bittman
%A David G. Watson
%A Susan Pyne
%A Nigel J. Pyne
%J Biomolecules
%D 2013
%I MDPI AG
%R 10.3390/biom3020316
%X We have previously shown that treatment of androgen-sensitive LNCaP cells with the sphingosine kinase (SK) inhibitor SKi (2-( p-hydroxyanilino)-4-( p-chlorophenyl)thiazole) induces the proteasomal degradation of two N-terminal variants of SK1 (SK1a and SK1b), increases C22:0-ceramide and diadenosine 5¡ä,5¡ä¡ä¡ä- P 1, P 3-triphosphate (Ap3A) and reduces S1P levels, and promotes apoptosis. We have now investigated the effects of three SK inhibitors (SKi, ( S)-FTY720 vinylphosphonate, and ( R)-FTY720 methyl ether) on metabolite and sphingolipid levels in androgen-sensitive LNCaP and androgen-independent LNCaP-AI prostate cancer cells. The 51 kDa N-terminal variant of SK1 (SK1b) evades the proteasome in LNCaP-AI cells, and these cells do not exhibit an increase in C22:0-ceramide or Ap3A levels and do not undergo apoptosis in response to SKi. In contrast, the SK inhibitor ( S)-FTY720 vinylphosphonate induces degradation of SK1b in LNCaP-AI, but not in LNCaP cells. In LNCaP-AI cells, ( S)-FTY720 vinylphosphonate induces a small increase in C16:0-ceramide levels and cleavage of polyADPribose polymerase (indicative of apoptosis). Surprisingly, the level of S1P is increased by 7.8- and 12.8-fold in LNCaP and LNCaP-AI cells, respectively, on treatment with ( S)-FTY720 vinylphosphonate. Finally, treatment of androgen-sensitive LNCaP cells with the SK2-selective inhibitor ( R)-FTY720 methyl ether increases lysophosphatidylinositol levels, suggesting that SK2 may regulate lyso-PI metabolism in prostate cancer cells.
%K Sphingosine kinase inhibitors
%K lyso-phosphatidylinositol
%K sphingolipids
%K diadenosine 5¡ä
%K 5¡ä¡ä¡ä-P1
%K P3-triphosphate
%U http://www.mdpi.com/2218-273X/3/2/316