Involvement of p27(kip1) in ceramide-mediated apoptosis in HL-60 cells.
Ceramide acts as a mediator of apoptosis in various cell lines, but little is known regarding the molecular mechanism linked to the cell cycle. In the present study, we examined the expression of p27(kip1) and its relationship to apoptosis induced by ceramide. We demonstrated that treatment of HL-60 cells with C6-ceramide resulted in G1 phase elevation followed by apoptotic cleavage associated with increase in the level of cdk inhibitor p27(kip1). Ceramide inhibited the kinase activities of cdk2 and cdk4 within 24 h of treatment. Ceramide-induced inhibition of cdk2 and cdk4 kinase activities was accompanied by increase of p27(kip1) in the cdks complexes. In addition, we have shown that both the cell death and expression of p27(kip1) protein induced by ceramide were significantly decreased in HL-60 cells overexpressing bcl-2. Furthermore, ceramide induced a significant increase in Bax protein expression coincided with increase in p27(kip1) protein level. These findings indicate that p27(kip1) may play important roles in mediating ceramide-induced apoptosis and its expression can be regulated by Bax and Bcl-2.
Kim
W H
WH
Department of Life Science, College of Natural Sciences, Chung-Ang University, Seoul, South Korea.
Ghil
K C
KC
Lee
J H
JH
Yeo
S H
SH
Chun
Y J
YJ
Choi
K H
KH
Kim
D K
DK
Kim
M Y
MY
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D042846:CDC2-CDC28 Kinases; D018797:Cell Cycle Proteins; D002518:Ceramides / Q000494:pharmacology*; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism; D019927:Cyclin E / Q000235:genetics / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics; D016193:G1 Phase; D005786:Gene Expression Regulation / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D007700:Kinetics; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D025521:Tumor Suppressor Proteins
D018797:Cell Cycle Proteins; D002518:Ceramides; D019927:Cyclin E; D008869:Microtubule-Associated Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D011994:Recombinant Proteins; D025521:Tumor Suppressor Proteins; C101954:N-caproylsphingosine; D019938:Cyclin D1; D050760:Cyclin-Dependent Kinase Inhibitor p27; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495900:CDK4 protein, human; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases