title: Caveolin-1 negatively regulates TRAIL-induced apoptosis in human hepatocarcinoma cells.
abstract: The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) offers promising therapeutic potential based on its ability to induce apoptosis in various cancer cell lines without obvious adverse effect to normal cells. However, the mechanism of the differential sensitivity towards TRAIL-induced apoptosis remains unclear. Here, we demonstrate that caveolin-1 directly regulated TRAIL-induced apoptosis in HepG2 cells. ShRNA-mediated caveolin knockdown sensitized TRAIL-induced apoptosis and disruption of caveolae structure by the cholesterol-extracting reagent, methyl-beta-cyclodextrin (MCD), enhanced TRAIL-induced apoptosis. Over-expression of caveolin-1 partially blocked TRAIL-induced apoptosis. The engagement of TRAIL with its receptor DR4 reduced the localization of DR4 in caveolae and resulted in its internalization. Blockade of caveolae-mediated internalization of DR4 by filipin III effectively enhanced TRAIL-induced apoptosis. Collectively, our results reveal a new mechanism by which caveolin-1 negatively regulates TRAIL-induced apoptosis in human hepatocarcinoma cells.
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Xiangxuan
authors.initials: X
authors.lastname: Zhao
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.forename: Qi
authors.initials: Q
authors.lastname: Ma
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Wang
authors.forename: Haijing
authors.initials: H
authors.lastname: Jin
authors.forename: Maryam
authors.initials: M
authors.lastname: Mehrpour
authors.forename: Quan
authors.initials: Q
authors.lastname: Chen
mesh_terms: D017209:Apoptosis; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology*
chemical_list: C495540:CAV1 protein, human; D051242:Caveolin 1; D034741:RNA, Small Interfering; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505653:TNFSF10 protein, human