title: LIGHT sensitizes IFNgamma-mediated apoptosis of MDA-MB-231 breast cancer cells leading to down-regulation of anti-apoptosis Bcl-2 family members.
abstract: LIGHT is a new member of the tumor necrosis factor superfamily, which binds to lymphotoxin beta receptor, herpes virus entry mediator, or TR6. This work was carried out to elucidate the molecular mechanism of LIGHT-sensitized, interferon gamma (IFNgamma)-mediated apoptosis of MDA-MB-231 cells. It was revealed that LIGHT treatment resulted in down-regulation of anti-apoptosis Bcl-2 family member: Bcl-2, Bcl-X(L), Bag-1, and Mcl-1; up-regulation of pro-apoptosis Bcl-2 family member: Bak and Ser (112)-phosphor-Bad; down-regulation of pro-apoptosis Bcl-2 member Bax; the other pro-apoptosis member Bid remains unaltered. LIGHT treatment also resulted in activation of caspase-3, caspase-6, caspase-7, caspase-8, caspase-9, DFF45, and PARP. However, caspase activation and caspase activity, especially caspase-3 activity, is not required for LIGHT-induced apoptosis of MDA-MB-231 cells, since caspase-3 inhibitor, benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone, and a broad range caspase inhibitor, benzyloxycarbonyl-val-ala-asp-fluoromethylketone failed to block the apoptosis induced by LIGHT and IFNgamma in MDA-MB-231 cells. In summary, LIGHT-sensitized IFNgamma-mediated apoptosis of MDA-MB-231 cells is probably through down-regulation of anti-apoptosis Bcl-2 family members; it could be caspase (especially caspase-3)-independent, even though extensive caspase activation was observed.
authors.affiliation: Structure Biology and Cancer Drug Discovery Program, Lombardi Cancer Center and Department of Oncology, Georgetown University Medical Center, Washington, DC 20007, USA. manchaoz@med.umich.edu
authors.forename: Manchao
authors.initials: M
authors.lastname: Zhang
authors.forename: Ribo
authors.initials: R
authors.lastname: Guo
authors.forename: Yifan
authors.initials: Y
authors.lastname: Zhai
authors.forename: Dajun
authors.initials: D
authors.lastname: Yang
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D051023:BH3 Interacting Domain Death Agonist Protein; D001943:Breast Neoplasms / Q000473:pathology*; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics; D020169:Caspases / Q000378:metabolism / Q000502:physiology; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004268:DNA-Binding Proteins; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D019254:Genes, bcl-2; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D009842:Oligopeptides / Q000494:pharmacology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors; D014407:Tumor Cells, Cultured / Q000187:drug effects; D053326:Tumor Necrosis Factor Ligand Superfamily Member 14; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D051017:Apoptosis Regulatory Proteins; C494772:BAK1 protein, human; C494826:BAX protein, human; C091732:BCL2-associated athanogene 1 protein; C494811:BCL2L1 protein, human; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D002352:Carrier Proteins; D015853:Cysteine Proteinase Inhibitors; D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D009842:Oligopeptides; D011506:Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C505914:TNFSF14 protein, human; D014157:Transcription Factors; D053326:Tumor Necrosis Factor Ligand Superfamily Member 14; D014409:Tumor Necrosis Factor-alpha; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C109664:caspase-activated DNase inhibitor; D007371:Interferon-gamma; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases