title: 1-Methoxy-canthin-6-one induces c-Jun NH2-terminal kinase-dependent apoptosis and synergizes with tumor necrosis factor-related apoptosis-inducing ligand activity in human neoplastic cells of hematopoietic or endodermal origin.
abstract: We investigated the effects of 1-methoxy-canthin-6-one, isolated from the medicinal plant Ailanthus altissima Swingle, on apoptosis in human leukemia (Jurkat), thyroid carcinoma (ARO and NPA), and hepatocellular carcinoma (HuH7) cell lines. Cultures incubated with the compound showed >50% of sub-G1 (hypodiploid) elements in flow cytometry analysis; the apoptosis-inducing activity was evident at <10 micromol/L and half-maximal at about 40 micromol/L 1-methoxy-canthin-6-one. The appearance of hypodiploid elements was preceded by mitochondrial membrane depolarization, mitochondrial release of cytochrome c, and Smac/DIABLO and procaspase-3 cleavage. We subsequently investigated the effect of 1-methoxy-canthin-6-one in combination with human recombinant tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in the four cell lines. Suboptimal concentrations (10 micromol/L 1-methoxy-canthin-6-one and 0.25 ng/mL TRAIL, respectively) of the two agents, unable to elicit apoptosis when used alone, induced mitochondrial depolarization, activation of caspase-3, and 45% to 85% of sub-G1 elements when added together to the cells. The synergism seemed to rely partly on the enhanced expression of TRAIL receptor 1 (TRAIL-R1; DR4), analyzed by immunofluorescence, by 1-methoxy-canthin-6-one. Cell incubation with 1-methoxy-canthin-6-one resulted in activating c-Jun NH2-terminal kinase (JNK), as revealed by Western blotting; induction of apoptosis and TRAIL-R1 up-regulation by 1-methoxy-canthin-6-one were >80% prevented by the addition of the JNK inhibitor (JNKI) SP600125JNKI, indicating that both effects were almost completely mediated by JNK activity. On the other hand, synergism with TRAIL was reduced by about 50%, suggesting that besides up-regulating TRAIL-R1, 1-methoxy-canthin-6-one could influence other factor(s) that participated in TRAIL-induced apoptosis. These findings indicate that 1-methoxy-canthin-6-one can represent a candidate for in vivo studies of monotherapies or combined antineoplastic therapies.
authors.affiliation: Department of Pharmaceutical Sciences (DiFarma), University of Salerno, Salerno, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Ammirante
authors.forename: Rita
authors.initials: R
authors.lastname: Di Giacomo
authors.forename: Laura
authors.initials: L
authors.lastname: De Martino
authors.forename: Alessandra
authors.initials: A
authors.lastname: Rosati
authors.forename: Michela
authors.initials: M
authors.lastname: Festa
authors.forename: Antonio
authors.initials: A
authors.lastname: Gentilella
authors.forename: Maria Carmela
authors.initials: MC
authors.lastname: Pascale
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Belisario
authors.forename: Arturo
authors.initials: A
authors.lastname: Leone
authors.forename: Maria Caterina
authors.initials: MC
authors.lastname: Turco
authors.forename: Vincenzo
authors.initials: V
authors.lastname: De Feo
mesh_terms: D032268:Ailanthus / Q000737:chemistry; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology; D045744:Cell Line, Tumor; D004357:Drug Synergism; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D019169:Jurkat Cells; D007938:Leukemia / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology; D008113:Liver Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D009287:Naphthyridines / Q000494:pharmacology*; D053221:TNF-Related Apoptosis-Inducing Ligand; D013964:Thyroid Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: C510719:1-methoxy-canthin-6-one; D051017:Apoptosis Regulatory Proteins; D007211:Indoles; D008562:Membrane Glycoproteins; D009287:Naphthyridines; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D048031:JNK Mitogen-Activated Protein Kinases