Tumor necrosis factor-related apoptosis-inducing ligand activates a lysosomal pathway of apoptosis that is regulated by Bcl-2 proteins.
The present studies were performed to determine whether lysosomal permeabilization contributes to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity and to reconcile a role for lysosomes with prior observations that Bcl-2 family members regulate TRAIL-induced apoptosis. In KMCH cholangiocarcinoma cells stably expressing Mcl-1 small interference RNA (siRNA), treatment with TRAIL induced a redistribution of the cathepsin B from lysosomes to the cytosol. Pharmacological and small hairpin RNA-targeted inhibition of cathepsin B attenuated TRAIL-mediated apoptosis as assessed by morphological, biochemical, and clonogenic assays. Neither Bid siRNA nor Bak siRNA prevented cathepsin B release. In contrast, treatment of the cells with Bim siRNA or the JNK inhibitor SP600125 attenuated lysosomal permeabilization and cell death. Moreover, Bim and active Bax co-localized to lysosomes in TRAIL-treated cells in a JNK-dependent manner, and Bax siRNA reduced TRAIL-induced lysosomal permeabilization and cell death. Finally, BH3 domain peptides permeabilized isolated lysosomes in the presence of Bax. Collectively, these data suggest that TRAIL can trigger an apoptotic pathway that involves JNK-dependent activation of Bim, which in turn induces Bax-mediated permeabilization of lysosomes.
Mayo Clinic College of Medicine, Rochester, Minnesota 55905.
Nathan W
NW
Werneburg
Mayo Clinic College of Medicine, Rochester, Minnesota 55905.
M Eugenia
ME
Guicciardi
Mayo Clinic College of Medicine, Rochester, Minnesota 55905.
Steve F
SF
Bronk
Mayo Clinic College of Medicine, Rochester, Minnesota 55905.
Scott H
SH
Kaufmann
Mayo Clinic College of Medicine, Rochester, Minnesota 55905. Electronic address: gores.gregory@mayo.edu.
Gregory J
GJ
Gores
D000873:Anthracenes / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D000072224:Bcl-2-Like Protein 11; D002401:Cathepsin B / Q000037:antagonists & inhibitors / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability / Q000187:drug effects; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D048670:MAP Kinase Kinase 4 / Q000037:antagonists & inhibitors / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism / Q000494:pharmacology; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
D000873:Anthracenes; D051017:Apoptosis Regulatory Proteins; C494772:BAK1 protein, human; C494826:BAX protein, human; C000606775:BCL2L11 protein, human; D000072224:Bcl-2-Like Protein 11; D008565:Membrane Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D010455:Peptides; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; C432165:pyrazolanthrone; D048670:MAP Kinase Kinase 4; D002401:Cathepsin B