Abstract
Osteosarcoma is the most common primary bone tumor associated with childhood and adolescence. In the present study, we investigated the anticancer effect of a new isoflavone derivative, 3',4'-dichloro-3-(3,4-dichlorophenylacetyl)-2,4,6-trihydroxydeoxybenzoin (DDTD) in human osteosarcoma cells. DDTD induced cell apoptosis in human osteosarcoma cell lines (including: U2OS, MG-63, Saos2 and ROS 17/2.8). We found that the accumulation of reactive oxygen species is a critical mediator in DDTD-induced cell death. DDTD induced apoptosis signal-regulating kinase 1 (ASK1) dephosphorylation and its dissociation from 14-3-3. Treatment of osteosarcoma cells with DDTD induced p38 and p53 phosphorylation. Transfection with ASK1, mitogen activated protein kinase (MAPK) kinase (MKK)3/6, and p38 small interfering RNA (siRNA) antagonized the DDTD-induced cell apoptosis. DDTD also triggered the mitochondrial apoptotic pathway, as indicated by a change in Bax/Bcl2 ratio and Caspase-9 activation. Bax knockdown using a Bax siRNA strategy reduced Bax expression and subsequent cell death. In addition, transfection of cells with ASK1, MKK3/6, and p38 siRNA reduced DDTD-induced p38 activation, p53 phosphorylation and Bax expression. These results suggest that DDTD generates reactive oxygen species and activates the ASK1-MKK3/6-p38-p53-Bax pathway to cause osteosarcoma cell death.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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14-3-3 Proteins / metabolism
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Antineoplastic Agents, Phytogenic / pharmacology*
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Apoptosis / drug effects*
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Caspase 9 / metabolism
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Cell Line, Tumor
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Dose-Response Relationship, Drug
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Humans
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Isoflavones / pharmacology*
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MAP Kinase Kinase 3 / metabolism
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MAP Kinase Kinase 6 / metabolism
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MAP Kinase Kinase Kinase 5 / genetics
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MAP Kinase Kinase Kinase 5 / metabolism*
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Mitochondria / enzymology
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Mitochondria / pathology
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Osteosarcoma / enzymology
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Osteosarcoma / genetics
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Osteosarcoma / pathology*
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Phosphorylation
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Phytoestrogens / pharmacology*
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Proto-Oncogene Proteins c-bcl-2 / metabolism
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RNA Interference
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RNA, Small Interfering / metabolism
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Reactive Oxygen Species / metabolism*
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Signal Transduction / drug effects*
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Time Factors
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Transfection
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Tumor Suppressor Protein p53 / metabolism
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bcl-2-Associated X Protein / metabolism
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p38 Mitogen-Activated Protein Kinases / metabolism
Substances
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14-3-3 Proteins
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3',4'-dichloro-3-(3,4-dichlorophenylacetyl)-2,4,6-trihydroxydeoxybenzoin
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Antineoplastic Agents, Phytogenic
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BAX protein, human
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Isoflavones
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Phytoestrogens
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Proto-Oncogene Proteins c-bcl-2
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RNA, Small Interfering
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Reactive Oxygen Species
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TP53 protein, human
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Tumor Suppressor Protein p53
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bcl-2-Associated X Protein
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p38 Mitogen-Activated Protein Kinases
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MAP Kinase Kinase Kinase 5
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MAP3K5 protein, human
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MAP Kinase Kinase 3
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MAP Kinase Kinase 6
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MAP2K3 protein, human
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MAP2K6 protein, human
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CASP9 protein, human
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Caspase 9