Abstract
A functional relationship between the apoptotic endonuclease DNAS1L3 and the chemotherapeutic drug VP-16 was established. The lymphoma cell line, Daudi, exhibited a significant resistance to VP-16 treatment in comparison to the lymphoma/leukemia cell line, U-937. While U-937 cells degraded their DNA into internucleosomal fragments, Daudi cells failed to undergo such fragmentation in response to the drug. Activation of both caspase-3 and DNA fragmentation factor was not sufficient to trigger internucleosomal DNA fragmentation in Daudi cells. No correlation was found between expression levels of topoisomerase-II, Pgp, Bcl-2, Bax, or Bad and decreased sensitivity of Daudi cells to VP-16. Daudi cells failed to express DNAS1L3 and ectopic expression of this protein significantly sensitized the cells to VP-16. An enhancement of caspase-3 activity and collapse of mitochondrial membrane potential underlie DNAS1L3-mediated sensitization of Daudi cells to VP-16, which may be a direct result of DNAS1L3-mediated increase in PARP-1-activating DNA breaks after VP-16 treatment. Our results suggest that DNAS1L3 plays an active role in lymphoma cell sensitization to VP-16 and that its deficiency may constitute a novel mechanism of drug resistance in these cells.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism
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Antineoplastic Agents / pharmacology*
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Antineoplastic Agents, Phytogenic / pharmacology
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Apoptosis Regulatory Proteins
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Apoptosis*
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Calcium / metabolism
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Caspase 3
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Caspases / metabolism
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Cell Line, Tumor
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DNA / metabolism
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DNA Damage
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DNA Fragmentation
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DNA Topoisomerases, Type II / metabolism
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Deoxyribonucleases / chemistry
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Deoxyribonucleases / metabolism
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Drug Resistance, Neoplasm
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Endodeoxyribonucleases / biosynthesis*
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Enzyme Activation
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Etoposide / pharmacology*
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Gene Deletion
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Gene Expression Regulation, Neoplastic
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Humans
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Immunoblotting
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In Situ Nick-End Labeling
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Intracellular Signaling Peptides and Proteins / metabolism
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Lymphoma / drug therapy*
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Magnesium / metabolism
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Membrane Potentials
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Nucleosomes / metabolism
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Poly-ADP-Ribose Binding Proteins
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Proteins / chemistry
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Proto-Oncogene Proteins c-bcl-2 / metabolism
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Reverse Transcriptase Polymerase Chain Reaction
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Sensitivity and Specificity
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Transfection
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U937 Cells
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bcl-2-Associated X Protein / metabolism
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bcl-Associated Death Protein / metabolism
Substances
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ATP Binding Cassette Transporter, Subfamily B, Member 1
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Antineoplastic Agents
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Antineoplastic Agents, Phytogenic
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Apoptosis Regulatory Proteins
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Intracellular Signaling Peptides and Proteins
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Nucleosomes
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Poly-ADP-Ribose Binding Proteins
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Proteins
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Proto-Oncogene Proteins c-bcl-2
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bcl-2-Associated X Protein
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bcl-Associated Death Protein
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caspase-activated DNase inhibitor
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Etoposide
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DNA
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DFFB protein, human
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DNASE1L3 protein, human
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Deoxyribonucleases
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Endodeoxyribonucleases
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CASP3 protein, human
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Caspase 3
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Caspases
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DNA Topoisomerases, Type II
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Magnesium
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Calcium