Arsenic induces apoptosis of multidrug-resistant human myeloid leukemia cells that express Bcr-Abl or overexpress MDR, MRP, Bcl-2, or Bcl-x(L).
We investigated the in vitro growth inhibitory and apoptotic effects of clinically achievable concentrations of As(2)O(3) (0.5 to 2.0 micromol/L) against human myeloid leukemia cells known to be resistant to a number of apoptotic stimuli. These included chronic myelocytic leukemia (CML) blast crisis K562 and HL-60/Bcr-Abl cells, which contain p210 and p185 Bcr-Abl, respectively, and HL-60 cell types that overexpress Bcl-2 (HL-60/Bcl-2), Bcl-x(L) (HL-60/Bcl-x(L)), MDR (HL-60/VCR), or MRP (HL-60/AR) protein. The growth-inhibitory IC(50) values for As(2)O(3) treatment for 7 days against all these cell types ranged from 0.8 to 1.5 micromol/L. Exposure to 2 micromol/L As(2)O(3) for 7 days induced apoptosis of all cell types, including HL-60/Bcr-Abl and K562 cells. This was associated with the cytosolic accumulation of cyt c and preapoptotic mitochondrial events, such as the loss of inner membrane potential (DeltaPsim) and the increase in reactive oxygen species (ROS). Treatment with As(2)O(3) (2 micromol/L) generated the activities of caspases, which produced the cleavage of the BH3 domain containing proapoptotic Bid protein and poly (ADP-ribose) polymerase. Significantly, As(2)O(3)-induced apoptosis of HL-60/Bcr-Abl and K562 cells was associated with a decline in Bcr-Abl protein levels, without any significant alterations in the levels of Bcl-x(L), Bax, Apaf-1, Fas, and FasL. Although As(2)O(3 )treatment caused a marked increase in the expression of the myeloid differentiation marker CD11b, it did not affect Hb levels in HL-60/Bcr-Abl, K562, or HL-60/neo cells. However, in these cells, As(2)O(3 )potently induced hyper-acetylation of the histones H3 and H4. These findings characterize As(2)O(3) as a growth inhibiting and apoptosis-inducing agent against a variety of myeloid leukemia cells resistant to multiple apoptotic stimuli.
Perkins
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Division of Clinical and Translational Research, Sylvester Comprehensive Cancer Center, University of Miami School of Medicine, Miami, FL 33136, USA.
Kim
C N
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Fang
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G
Bhalla
K N
KN
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000235:genetics; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000235:genetics; D000107:Acetylation / Q000187:drug effects; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053477:Apoptotic Protease-Activating Factor 1; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D053222:Fas Ligand Protein; D016044:Fusion Proteins, bcr-abl / Q000096:biosynthesis* / Q000235:genetics; D015973:Gene Expression Regulation, Leukemic; D019254:Genes, bcl-2; D018922:HL-60 Cells / Q000187:drug effects*; D006657:Histones / Q000378:metabolism; D006801:Humans; D016130:Immunophenotyping; D020014:K562 Cells / Q000187:drug effects*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics / Q000473:pathology*; D016177:Macrophage-1 Antigen / Q000096:biosynthesis / Q000235:genetics; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D008928:Mitochondria / Q000378:metabolism; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D010087:Oxides / Q000494:pharmacology*; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011506:Proteins / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics*; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D019014:fas Receptor / Q000096:biosynthesis / Q000235:genetics
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; D000970:Antineoplastic Agents; D053477:Apoptotic Protease-Activating Factor 1; D000077237:Arsenic Trioxide; D001152:Arsenicals; D020169:Caspases; D003574:Cytochrome c Group; D053222:Fas Ligand Protein; D016044:Fusion Proteins, bcr-abl; D006657:Histones; D016177:Macrophage-1 Antigen; D008562:Membrane Glycoproteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; D010087:Oxides; D011506:Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D019014:fas Receptor; C506592:APAF1 protein, human; C494826:BAX protein, human; C494811:BCL2L1 protein, human; C505661:FASLG protein, human