title: 2'-Nitroflavone induces apoptosis and modulates mitogen-activated protein kinase pathways in human leukaemia cells.
abstract: The cytotoxic activity of 2'-nitroflavone was evaluated in different haematological cancer cell lines and its mechanism of action was further studied in HL-60 cells. 2'-Nitroflavone arrested the cell cycle at the G(2)/M phase and induced an apoptotic response characterized by an increase in the sub-G1 fraction of cells, a typical DNA ladder fragmentation, chromatin condensation and the detection of cells stained with Annexin V. Apoptosis was dependent on the activation of at least caspase-8, caspase-9 and caspase-3. The involvement of the death receptor pathway was indicated by the upregulation of both the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and its death receptor (DR5). We also showed that 2'-nitroflavone increased the expression levels of Bax and induced the release of cytochrome C to cytosol, suggesting the participation of the mitochondria-dependent pathway. When mitogen-activated protein kinases pathways were studied, it was found that p38 and c-Jun NH(2)-terminal kinase (JNK) pathways were activated by 2'-nitroflavone in HL-60 cells, whereas the phosphorylation levels of extracellular signal-regulated kinases (ERK) 1/2 decreased significantly. In addition, whereas both pharmacological inhibition of JNK and downregulation of JNK expression by RNA interference reduced the nitroflavone growth-inhibitory activity and the apoptotic effect, contrasting results were obtained when the ERK1/2 pathway was inhibited, and no effect was observed in the presence of a specific inhibitor of p38 mitogen-activated protein kinase. These findings show for the first time the antitumour action of 2'-nitroflavone in haematological cancer cell lines and suggest that both JNK and ERK1/2 cascades are involved in the apoptotic response induced by 2'-nitroflavone in HL-60 cells.
authors.affiliation: Institute of Biochemistry and Biophysics, School of Pharmacy and Biochemistry, University of Buenos Aires, Argentina.
authors.forename: Mariano G
authors.initials: MG
authors.lastname: Cárdenas
authors.forename: Viviana C
authors.initials: VC
authors.lastname: Blank
authors.forename: Mariel N
authors.initials: MN
authors.lastname: Marder
authors.forename: Leonor P
authors.initials: LP
authors.lastname: Roguin
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D053938:DNA Fragmentation / Q000187:drug effects; D047309:Flavones / Q000494:pharmacology*; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects; D018922:HL-60 Cells; D019337:Hematologic Neoplasms / Q000188:drug therapy / Q000473:pathology; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D015473:Leukemia, Promyelocytic, Acute / Q000188:drug therapy* / Q000473:pathology; D059566:M Phase Cell Cycle Checkpoints / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: C532168:2'-nitroflavone; D000970:Antineoplastic Agents; D047309:Flavones; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D020169:Caspases