title: Chemotherapy enhances TNF-related apoptosis-inducing ligand DISC assembly in HT29 human colon cancer cells.
abstract: Cytokines such as Fas-ligand (Fas-L) and Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) can induce human colon cancer cell apoptosis through engagement of their death domain receptors. All the cancer cells are not sensitive to these cytokines. We have shown recently that low doses of cytotoxic drugs could restore TRAIL-induced cell death in resistant colon cancer cell lines. The present work further explores the death pathway triggered by the cytotoxic drug/TRAIL combination in HT-29 colon cancer cells (www.alexis-corp.com). Clinically relevant concentrations of cisplatin, doxorubicin and 5-fluorouracil synergize with TRAIL to trigger HT-29 cell death. Activation of this pathway leads to apoptosis that involves both caspases and the mitochondria. An increased recruitment of Fas-associated death domain (FADD) and procaspase-8 to the TRAIL-induced death-inducing signaling complex (DISC) was shown in cells exposed to anticancer drugs. Following caspase-8 activation at the DISC level, the mitochondria-dependent death pathway is activated, as demonstrated by the cleavage of Bid, the dissipation of DeltaPsi(m), the release of mitochondrial proteins in the cytosol and the inhibitory effect of Bcl-2 expression. Importantly, besides mitochondrial potentiation, we show here that cytotoxic drugs sensitize HT-29 colon cancer cells to TRAIL-induced cell death by enhancing FADD and procaspase-8 recruitment to the DISC, a novel mechanism whose efficacy could depend partly on Bcl-2 expression level.
authors.affiliation: INSERM U517, IFR 100, Faculty of Medicine, Dijon, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Lacour
authors.forename: Olivier
authors.initials: O
authors.lastname: Micheau
authors.forename: Arlette
authors.initials: A
authors.lastname: Hammann
authors.forename: Véronique
authors.initials: V
authors.lastname: Drouineaud
authors.forename: Jurg
authors.initials: J
authors.lastname: Tschopp
authors.forename: Eric
authors.initials: E
authors.lastname: Solary
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Dimanche-Boitrel
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D051023:BH3 Interacting Domain Death Agonist Protein; D002352:Carrier Proteins / Q000378:metabolism; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D004789:Enzyme Activation; D019073:HT29 Cells; D006801:Humans; D008024:Ligands; D008562:Membrane Glycoproteins / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D002352:Carrier Proteins; D008024:Ligands; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases