title: IFN-beta induces caspase-mediated apoptosis by disrupting mitochondria in human advanced stage colon cancer cell lines.
abstract: Various human colon cancer cell lines tested in vitro differed significantly in susceptibility to growth inhibition of recombinant human interferon-beta (rHuIFN-beta). Two p53-mutant lines, COH and CC-M2, derived from high-grade colon adenocarcinoma, showed signs of apoptosis after treatment with 250 IU/ml of HuIFN- beta in the culture medium. The similarly p53-mutated HT-29 line from a grade I adenocarcinoma showed no apoptosis, however, and only cell cycle G1/G0 or S phase retardation with 1000 IU/ml HuIFN-beta. After HuIFN-beta exposure, COH and CC-M2 cells showed increased levels of Fas and FasL proteins, alteration of mitochondrial membrane potential, and activation of caspase-9, caspase-8, and caspase-3 in a time-dependent manner. Treatment of COH and CC-M2 cells with anti-FasL antibodies or rFas/Fc fusion protein, however, could not prevent the apoptosis induced by HuIFN-beta. In contrast, cell-permeable specific inhibitors of the three caspases could inhibit the DNA fragmentation and cell death but not the mitochondrial membrane potential changes. Treatment with mitochondria-stabilizing reagents could significantly abrogate the apoptosis and caspase activation induced by HuIFN-beta. These results suggest that in COH and CC-M2 colon cancer cell lines, HuIFN-beta induces apoptosis mainly through mitochondrial membrane alteration and subsequent activation of the caspase cascade pathway, but not by the Fas/FasL interaction or the p53-dependent apoptotic mechanism.
authors.affiliation: Cancer Research Cooperative Laboratory, NHRI, Taipei 100, ROC.
authors.forename: Shin-Hun
authors.initials: SH
authors.lastname: Juang
authors.forename: Sung-Jen
authors.initials: SJ
authors.lastname: Wei
authors.forename: Yi-Mei
authors.initials: YM
authors.lastname: Hung
authors.forename: Chiung-Yueh
authors.initials: CY
authors.lastname: Hsu
authors.forename: Den-Mei
authors.initials: DM
authors.lastname: Yang
authors.forename: Ko-Jiunn
authors.initials: KJ
authors.lastname: Liu
authors.forename: Wei-Shone
authors.initials: WS
authors.lastname: Chen
authors.forename: Wen K
authors.initials: WK
authors.lastname: Yang
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects*; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology*; D045304:Cytochromes c / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D053222:Fas Ligand Protein; D016158:Genes, p53 / Q000235:genetics; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology* / Q000633:toxicity; D008562:Membrane Glycoproteins / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D009154:Mutation / Q000235:genetics; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; D051028:bcl-2-Associated X Protein; D019014:fas Receptor
chemical_list: D000970:Antineoplastic Agents; D061945:Caspase Inhibitors; C491901:FAS protein, human; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D007370:Interferon Type I; D008562:Membrane Glycoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; D051028:bcl-2-Associated X Protein; D019014:fas Receptor; D045304:Cytochromes c; D020169:Caspases