Phytosphingosine induced mitochondria-involved apoptosis.
Sphingolipids are putative intracellular signal mediators in cell differentiation, growth inhibition, and apoptosis. Sphingosine, sphinganine, and phytosphingosine are structural analogs of sphingolipids and are classified as long-chain sphingoid bases. Sphingosine and sphinganine are known to play important roles in apoptosis. In the present study, we examined the phytosphingosine-induced apoptosis mechanism, focusing on mitochondria in human T-cell lymphoma Jurkat cells. Phytosphingosine significantly induced chromatin DNA fragmentation, which is a hallmark of apoptosis. Enzymatic activity measurements of caspases revealed that caspase-3 and caspase-9 are activated in phytosphingosine-induced apoptosis, but there is little activation of caspase-8 suggesting that phytosphingosine influences mitochondrial functions. In agreement with this hypothesis, a decrease in DeltaPsi(m) and the release of cytochrome c to the cytosol were observed upon phytosphingosine treatment. Furthermore, overexpression of mitochondria-localized anti-apoptotic protein Bcl-2 prevented phytosphingosine apoptotic stimuli. Western blot assays revealed that phytosphingosine decreases phosphorylated Akt and p70S6k. Dephosphorylation of Akt was partially inhibited by protein phosphatase inhibitor OA and OA attenuated phytosphingosine-induced apoptosis. Moreover, using a cell-free system, phytosphingosine directly reduced DeltaPsi(m). These results indicate that phytosphingosine perturbs mitochondria both directly and indirectly to induce apoptosis.
Nagahara
Yukitoshi
Y
Department of Biotechnology, College of Science and Engineering, Tokyo Denki University, Hatoyama, Hiki-gun, Saitama, 350-0394, Japan.
Shinomiya
Takahisa
T
Kuroda
Sachiko
S
Kaneko
Naoki
N
Nishio
Reiji
R
Ikekita
Masahiko
M
D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000378:metabolism; D010766:Phosphorylation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology*
D019253:Proto-Oncogene Proteins c-bcl-2; D045304:Cytochromes c; D020169:Caspases; C012491:phytosphingosine; D013110:Sphingosine
Biochem J. 1999 Feb 15;338 ( Pt 1):161-6
9931312
Cell. 1997 Nov 14;91(4):479-89
9390557
Cell. 1998 Aug 21;94(4):481-90
9727491
Cell. 2000 Jul 7;102(1):33-42
10929711
Biochem Mol Biol Int. 1997 May;41(6):1179-89
9161713
J Cell Physiol. 2001 Aug;188(2):188-93
11424085
Clin Cancer Res. 2003 Feb;9(2):878-85
12576463
Biochem Biophys Res Commun. 1998 Sep 8;250(1):88-93
9735337
J Biol Chem. 1997 Sep 26;272(39):24101-4
9305851
Mol Cell Biol. 2000 Sep;20(18):6945-57
10958690
Proc Natl Acad Sci U S A. 1998 Dec 8;95(25):14681-6
9843949
Oncogene. 2000 Jun 29;19(28):3146-55
10918569
Mol Pharmacol. 2000 Apr;57(4):652-8
10727509
Pharmacol Res. 2003 May;47(5):383-92
12676512
J Biol Chem. 1986 Sep 25;261(27):12604-9
3462188
Cell. 1997 Aug 8;90(3):405-13
9267021
Proc Natl Acad Sci U S A. 2001 Apr 10;98(8):4622-7
11274365
J Biol Chem. 2002 Apr 19;277(16):14040-7
11842081
J Biol Chem. 1998 Dec 18;273(51):33942-8
9852046
J Biol Chem. 2001 Aug 10;276(32):30359-65
11387313
J Biol Chem. 2002 Mar 1;277(9):7610-8
11751859
Trends Biochem Sci. 1995 Feb;20(2):73-7
7701566
Cell. 1996 Jul 12;86(1):147-57
8689682
Blood. 1999 Jan 15;93(2):686-93
9885231
J Biol Chem. 1986 Sep 25;261(27):12610-5
3462189
FEBS Lett. 2004 Jul 2;569(1-3):249-55
15225643
J Biol Chem. 2000 Mar 24;275(12):8271-4
10722653
Cell. 2000 Jul 7;102(1):43-53
10929712
Dermatologica. 1991;183(2):77-94
1743378
Annu Rev Biochem. 1998;67:27-48
9759481
J Chromatogr B Biomed Appl. 1994 Jun 3;656(1):65-71
7952048
Science. 1998 Nov 13;282(5392):1318-21
9812896
Oncogene. 1998 Feb 26;16(8):1055-63
9519879
Br J Pharmacol. 2003 Apr;138(7):1303-12
12711631
Biochemistry. 1994 Aug 2;33(30):9007-12
7519054
Nature. 1999 Feb 4;397(6718):441-6
9989411
J Biol Chem. 2003 Dec 12;278(50):50624-34
14522966
Genes Dev. 2001 Jun 1;15(11):1406-18
11390360
J Immunol. 2000 Sep 15;165(6):3250-9
10975841