Sphingosine mediates FTY720-induced apoptosis in LLC-PK1 cells.
FTY720, a synthetic sphingoid base analog, was examined as a new sphingosine kinase inhibitor, which converts endogenous sphingosine into its phosphate form. With 20 microM of FTY720, sphingosine accumulated in the LLC-PK(1) cells in a time- and dose-dependent manner. The FTY720 treated cells showed a high concentration of fragmented DNA, a high caspase-3 like activity and TUNEL staining cells. It was also found that the sphingosine and sphinganine level increased in a time- and dose-dependent manner within 12 h after the FTY720 treatment. The sphingosine kinase activity was reduced by FTY720 as much as other sphingosine kinase inhibitors, N, N-dimethylsphingosine (DMS), dl-threo-dihydrosphingosine (DHS). The fragmented DNA content as a result of the 20 microM of FTY720 treatment and by 5 microM of the exogenously added BSA-sphingosine complex indicated typical apoptosis. Under similar conditions, the accumulated sphingosine concentration in all the cells was almost identical even though the sphingosine distribution inside the cells was somewhat different. These results indicate that the FTY720 induced apoptosis is associated with the inhibition of the sphingosine kinase activity and is strongly associated with the successive accumulation of sphingosine.
Lee
Woo-Jin
WJ
College of Pharmacy, Chungbuk National University, Chongju 361-763, Korea.
Yoo
Hwan-Soo
HS
Suh
Pann-Ghill
PG
Oh
Seikwan
S
Lim
Jong-Seok
JS
Lee
Yong-Moon
YM
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis; D002460:Cell Line; D053938:DNA Fragmentation; D042783:Endothelial Cells / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D000068876:Fingolimod Hydrochloride; D007668:Kidney / Q000166:cytology; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000502:physiology; D011409:Propylene Glycols / Q000494:pharmacology*; D013110:Sphingosine / Q000494:pharmacology / Q000502:physiology*; D013552:Swine; D015854:Up-Regulation; D000099157:Sphingosine Kinase
D053148:Caspase 3; D020169:Caspases; D004791:Enzyme Inhibitors; D000068876:Fingolimod Hydrochloride; D017853:Phosphotransferases (Alcohol Group Acceptor); D011409:Propylene Glycols; D013110:Sphingosine; D000099157:Sphingosine Kinase