Abstract
Recent clinical studies in China and USA showed that arsenic trioxide (As2O3) is an effective treatment of acute promyelocytic leukemia (APL) patients refractory to all-trans retinoic acid (RA). We here investigate the effects of As2O3 on RA-resistant APL in vivo and in vitro using our RA-resistant APL model system. As2O3 can induce inhibition of cellular growth of both RA-sensitive NB4 and RA-resistant UF-1 APL cells via induction of apoptosis in vitro. The expression of BCL-2 protein decreased in a dose- and time-dependent manner in NB4 cells. Interestingly, the levels of BCL-2 protein were not modulated by As2O3, but it did upregulate BAX protein in UF-1 cells. UF-1 cells (1x10(7)) were transplanted into hGM-CSF-producing transgenic SCID mice and successfully formed subcutaneous tumors. After 40 days of implantation, mice were treated with As2O3, all-trans RA and PBS for 21 days. In all-trans RA- and PBS-treated mice, tumors grew rapidly, with a 4.5-fold increase in volume at day 21 compared to the initial size. In marked contrast, tumor size was decreased to half of the initial size by the treatment of As2O3, which resulted in cells with the typical appearance of apoptosis. Interestingly, one of the As2O3-treated mice showed mature granulocytes in the diminished tumor, suggesting that As2O3 had dual effects on RA-resistant APL cells in vivo: both inducing apoptosis and differentiation of the leukemic cells. We conclude that our RA-resistant APL model will be useful for evaluating novel therapeutic approaches to patients with RA-resistant APL, and for further investigation of the metabolism of As2O3 in vivo.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antineoplastic Agents / pharmacology*
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Antineoplastic Agents / therapeutic use
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Apoptosis / drug effects*
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Arsenic Trioxide
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Arsenicals / pharmacology*
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Arsenicals / therapeutic use
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Carrier Proteins / biosynthesis
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Carrier Proteins / genetics
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Cell Cycle / drug effects
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Cell Differentiation / drug effects
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Cell Division / drug effects
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Drug Resistance, Neoplasm
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Granulocyte-Macrophage Colony-Stimulating Factor / biosynthesis
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Granulocyte-Macrophage Colony-Stimulating Factor / genetics
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Granulocyte-Macrophage Colony-Stimulating Factor / physiology*
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Humans
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Leukemia, Promyelocytic, Acute / pathology*
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Mice
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Mice, SCID
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Mice, Transgenic
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Neoplasm Proteins / biosynthesis
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Neoplasm Proteins / genetics
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Neoplasm Transplantation
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Oxides / pharmacology*
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Oxides / therapeutic use
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Proto-Oncogene Proteins / biosynthesis
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins c-bcl-2 / biosynthesis
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Proto-Oncogene Proteins c-bcl-2 / genetics
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Recombinant Fusion Proteins / biosynthesis
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Recombinant Fusion Proteins / physiology
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Transplantation, Heterologous
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Tretinoin / pharmacology*
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Tretinoin / therapeutic use
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Tumor Cells, Cultured / drug effects
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Tumor Cells, Cultured / pathology
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bcl-2-Associated X Protein
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bcl-Associated Death Protein
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bcl-X Protein
Substances
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Antineoplastic Agents
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Arsenicals
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BAD protein, human
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BAX protein, human
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BCL2L1 protein, human
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Bad protein, mouse
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Bax protein, mouse
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Bcl2l1 protein, mouse
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Carrier Proteins
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Neoplasm Proteins
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Oxides
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-bcl-2
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Recombinant Fusion Proteins
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bcl-2-Associated X Protein
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bcl-Associated Death Protein
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bcl-X Protein
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Tretinoin
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Granulocyte-Macrophage Colony-Stimulating Factor
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Arsenic Trioxide