%0 Journal Article
%T Ceramide induces release of mitochondrial proapoptotic proteins in caspase-dependent and -independent manner in HT-29 cells<br>
%A XiaoFeng Zhang
%A BaiXiang Li
%A Yang Zhang
%A JiaRen Liu
%A <br>
%J 中国科学C辑(英文版)
%D 2008
%I Springer
%X In this study, the release of mitochondrial proapoptotic intermembrane space proteins induced by exogenous C2-ceramide in human colon carcinoma (HT-29) cell line was investigated. HT-29 cells were treated with 12.5, 25 and 50 μmol/L C2-ceramide in vitro. Flow cytometer was used to detect the mitochondrial membrane potential (ΔΦm). Subcellular fractions were extracted by Mitochondrial/Cytosol Fractionation Kit after C2-ceramide treatment for 24 h. SDS-PAGE was used to determine the level of cytochrome c (Cyt c), high temperature requirement A2 (HtrA2) and second mitochondrial-derived activator of caspases (Smac) released from mitochondria, the expression of X-linked inhibitor of apoptosis protein (XIAP) and caspase-3 for 24 h. The results showed that ΔΦm began to decrease from 6 h after 25 and 50 μmol/L C2-ceramide treatment (P<0.05) and cyclosporin A (CsA) could inhibit the collapse of ΔΦm through regulating mitochondrial membrane permeability transition pore. There was no effect of C2-ceramide on the expression of Cyt c, HtrA2 and Smac in the total levels. 12.5, 25 and 50 μmol/L C2-ceramide could induce Cyt c, HtrA2 and Smac to release from mitochondria to cytosol and down-regulate the expression of XIAP (P<0.05). Also there was expression of cleaved caspase-3 with C2-ceramide treatment. After the treatment with caspase inhibitor, C2-ceramide still induced the release of Cyt c and HtrA2, but Smac did not. Therefore, C2-ceramide could induce apoptosis of HT-29 cells through the mitochondria pathway. The release of Cyt c, HtrA2 and Smac from mitochondria did not occur via the same mechanism, the release of Cyt c and HtrA2 was caspase-independent and the release of Smac was caspase-dependent. Supported by the National Natural Science Foundation of China (Grant No. 30471447) and Special-Purpose Scientific Research Foundation of Ph.D Subject in the Colleges and Universities of China (Grant No. 20060226004)
%K C_2-ceramide
%K mitochondria proapoptotic intermembrane space proteins
%K mitochondrial membrane potential
%K human colon carcinoma cells
%K caspase<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=90BA3D13E7F3BC869AC96FB3DA594E3FE34FBF7B8BC0E591&jid=180CF3A72E750F3261A8A60EDC957784&aid=B200FB85F2E0BE5D22E8960F862A7A68&yid=67289AFF6305E306&vid=987EDA49D8A7A635&iid=CA4FD0336C81A37A&sid=5C3443B19473A746&eid=4F2F18DD6F870C2C&journal_id=1674-7305&journal_name=ScienceChina.Lifesciences&referenced_num=0&reference_num=22