Arsenic induces apoptosis of multidrug-resistant human myeloid leukemia cells that express Bcr-Abl or overexpress MDR, MRP, Bcl-2, or Bcl-x(L)

• Published in: Blood Vol. 95; no. 3; p. 1014
• Main Authors: Perkins, C, Kim, C N, Fang, G, Bhalla, K N
• Format: Journal Article
• Language: English
• Published: United States 01.02.2000
• Subjects: Acetylation - drug effects; Antineoplastic Agents - pharmacology; Apoptosis - drug effects; Apoptotic Protease-Activating Factor 1; Arsenic Trioxide; Arsenicals - pharmacology; ATP Binding Cassette Transporter, Subfamily B, Member 1 - biosynthesis; ATP Binding Cassette Transporter, Subfamily B, Member 1 - genetics; ATP-Binding Cassette Transporters - biosynthesis; ATP-Binding Cassette Transporters - genetics; bcl-2-Associated X Protein; bcl-X Protein; Caspases - metabolism; Cytochrome c Group - metabolism; Cytosol - metabolism; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Fas Ligand Protein; fas Receptor - biosynthesis; fas Receptor - genetics; Fusion Proteins, bcr-abl - biosynthesis; Fusion Proteins, bcr-abl - genetics; Gene Expression Regulation, Leukemic; Genes, bcl-2; Histones - metabolism; HL-60 Cells - drug effects; Humans; Immunophenotyping; K562 Cells - drug effects; Leukemia, Myelogenous, Chronic, BCR-ABL Positive - genetics; Leukemia, Myelogenous, Chronic, BCR-ABL Positive - pathology; Macrophage-1 Antigen - biosynthesis; Macrophage-1 Antigen - genetics; Membrane Glycoproteins - biosynthesis; Membrane Glycoproteins - genetics; Mitochondria - metabolism; Multidrug Resistance-Associated Proteins; Neoplasm Proteins - biosynthesis; Neoplasm Proteins - genetics; Oxides - pharmacology; Protein Biosynthesis; Protein Processing, Post-Translational - drug effects; Proteins - genetics; Proto-Oncogene Proteins - biosynthesis; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins c-bcl-2 - biosynthesis; Proto-Oncogene Proteins c-bcl-2 - genetics
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V95.3.1014.003k04_1014_1022

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.