Potential mechanisms involved in ceramide-induced apoptosis in human colon cancer HT29 cells.
OBJECTIVE
To investigate the potential mechanisms of cell death after the treatment with ceramide.


METHODS
MTT assay, DNA ladder, reporter assay, FACS and Western blot assay were employed to investigate the potential mechanisms of cell death after the treatment with C2-ceramide.


RESULTS
A short-time treatment with C2-ceramide induced cell death, which was associated with p38 MAP kinase activation, but had no links with typical caspase activation or PARP degradation. Rather than caspase inhibitor, Inhibitor of p38 MAP kinase blocked cell death induced by a short-time treatment with ceramide (<12 h). However, inhibition of p38 MAP kinase could not block cell death induced by a prolonged treatment with ceramide (>12 h). Moreover, incubation of cells with ceramide for a long time (>12 h) increased subG1, but reduced S phase accompanied by caspase-dependent and caspase-independent changes including NFkappaB activation.


CONCLUSIONS
Ceramide-induced cell apoptosis involves both caspase-dependent and -independent signaling pathway. Caspase-independent cell death occurring in a relatively early stage, which is mediated via p38 MAP kinase, can progress into a stage involving both caspase-dependent and -independent mechanisms accompanied by cell signaling of MAPKs and NFkappaB.
Wang
Jing
J
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. avaecn@gmail.com
Lv
Xiao-Wen
XW
Du
Yu-Guo
YG
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D020169:Caspases / Q000378:metabolism / Q000502:physiology; D005434:Flow Cytometry; D019073:HT29 Cells; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology
C064769:N-acetylsphingosine; D016328:NF-kappa B; D048051:p38 Mitogen-Activated Protein Kinases; D020169:Caspases; D013110:Sphingosine