Low-level expression of proapoptotic Bcl-2-interacting mediator in leukemic cells in patients with chronic myeloid leukemia: role of BCR/ABL, characterization of underlying signaling pathways, and reexpression by novel pharmacologic compounds.

Chronic myeloid leukemia (CML) is a myeloproliferative disease in which BCR/ABL enhances survival of leukemic cells through modulation of proapoptotic and antiapoptotic molecules. Recent data suggest that proapoptotic Bcl-2-interacting mediator (Bim) plays a role as a tumor suppressor in myeloid cells, and that leukemic cells express only low amounts of this cell death activator. We here show that primary CML cells express significantly lower amounts of bim mRNA and Bim protein compared with normal cells. The BCR/ABL inhibitors imatinib and AMN107 were found to promote expression of Bim in CML cells. To provide direct evidence for the role of BCR/ABL in Bim modulation, we employed Ba/F3 cells with doxycycline-inducible expression of BCR/ABL and found that BCR/ABL decreases expression of bim mRNA and Bim protein in these cells. The BCR/ABL-induced decrease in expression of Bim was found to be a posttranscriptional event that depended on signaling through the mitogen-activated protein kinase pathway and was abrogated by the proteasome inhibitor MG132. Interestingly, MG132 up-regulated the expression of bim mRNA and Bim protein and suppressed the growth of Ba/F3 cells containing wild-type BCR/ABL or imatinib-resistant mutants of BCR/ABL. To show functional significance of "Bim reexpression," a Bim-specific small interfering RNA was applied and found to rescue BCR/ABL-transformed leukemic cells from imatinib-induced cell death. In summary, our data identify BCR/ABL as a Bim suppressor in CML cells and suggest that reexpression of Bim by novel tyrosine kinase inhibitors, proteasome inhibition, or by targeting signaling pathways downstream of BCR/ABL may be an attractive therapeutic approach in imatinib-resistant CML.

[1]  S. Derdak,et al.  Identification of mcl-1 as a BCR/ABL-dependent target in chronic myeloid leukemia (CML): evidence for cooperative antileukemic effects of imatinib and mcl-1 antisense oligonucleotides. , 2005, Blood.

[2]  A. Strasser.  The role of BH3-only proteins in the immune system , 2005, Nature Reviews Immunology.

[3]  Donna Neuberg,et al.  Characterization of AMN107, a selective inhibitor of native and mutant Bcr-Abl. , 2005, Cancer cell.

[4]  E. Wickstrom,et al.  Inhibition of Glucocorticoid-induced Apoptosis by Targeting the Major Splice Variants of BIM mRNA with Small Interfering RNA and Short Hairpin RNA* , 2004, Journal of Biological Chemistry.

[5]  T. Inaba.  Cytokine-Mediated Cell Survival , 2004, International journal of hematology.

[6]  T. Inaba,et al.  Roles of Bim in Apoptosis of Normal and Bcr-Abl-Expressing Hematopoietic Progenitors , 2004, Molecular and Cellular Biology.

[7]  O. Wagner,et al.  Identification of heme oxygenase-1 as a novel BCR/ABL-dependent survival factor in chronic myeloid leukemia. , 2004, Cancer research.

[8]  D. Hancock,et al.  Role of Bim in the survival pathway induced by Raf in epithelial cells , 2004, Oncogene.

[9]  S. Cook,et al.  Extracellular Signal-regulated Kinases 1/2 Are Serum-stimulated “BimEL Kinases” That Bind to the BH3-only Protein BimEL Causing Its Phosphorylation and Turnover* , 2004, Journal of Biological Chemistry.

[10]  G. Pagès,et al.  Phosphorylation of Bim-EL by Erk1/2 on serine 69 promotes its degradation via the proteasome pathway and regulates its proapoptotic function , 2003, Oncogene.

[11]  J. Griffin,et al.  Resistance to imatinib (Glivec): update on clinical mechanisms. , 2003, Drug resistance updates : reviews and commentaries in antimicrobial and anticancer chemotherapy.

[12]  P. Coffer,et al.  FOXO transcription factors directly activate bim gene expression and promote apoptosis in sympathetic neurons , 2003, The Journal of cell biology.

[13]  B. Druker,et al.  Several Bcr-Abl kinase domain mutants associated with imatinib mesylate resistance remain sensitive to imatinib. , 2003, Blood.

[14]  S. Cook,et al.  Activation of the ERK1/2 Signaling Pathway Promotes Phosphorylation and Proteasome-dependent Degradation of the BH3-only Protein, Bim* , 2003, Journal of Biological Chemistry.

[15]  E. Wagner,et al.  Activation of ERK1/2 by ΔRaf-1 : ER* represses Bim expression independently of the JNK or PI3K pathways , 2003, Oncogene.

[16]  H. Kantarjian,et al.  The proteasome inhibitor PS-341 inhibits growth and induces apoptosis in Bcr/Abl-positive cell lines sensitive and resistant to imatinib mesylate. , 2003, Haematologica.

[17]  Christian Sillaber,et al.  BCR/ABL induces expression of vascular endothelial growth factor and its transcriptional activator, hypoxia inducible factor-1alpha, through a pathway involving phosphoinositide 3-kinase and the mammalian target of rapamycin. , 2002, Blood.

[18]  W. Van den Broeck,et al.  Morphological and Biochemical Aspects of Apoptosis, Oncosis and Necrosis , 2002, Anatomia, histologia, embryologia.

[19]  C. Sawyers,et al.  Molecular mechanisms of resistance to STI571 in chronic myeloid leukemia , 2002, Current opinion in hematology.

[20]  M. Wasik,et al.  Complementary functions of the antiapoptotic protein A1 and serine/threonine kinase pim-1 in the BCR/ABL-mediated leukemogenesis. , 2002, Blood.

[21]  B. Druker,et al.  Molecular and chromosomal mechanisms of resistance to imatinib (STI571) therapy , 2002, Leukemia.

[22]  P. N. Rao,et al.  Clinical Resistance to STI-571 Cancer Therapy Caused by BCR-ABL Gene Mutation or Amplification , 2001, Science.

[23]  M. Andreeff,et al.  Expression of apoptosis proteins in chronic myelogenous leukemia , 2001, Cancer.

[24]  A. Look,et al.  Downregulation of Bim, a Proapoptotic Relative of Bcl-2, Is a Pivotal Step in Cytokine-Initiated Survival Signaling in Murine Hematopoietic Progenitors , 2001, Molecular and Cellular Biology.

[25]  J. Griffin,et al.  Mechanisms of resistance imatinib (STI571) in preclinical models and in leukemia patients. , 2001, Drug resistance updates : reviews and commentaries in antimicrobial and anticancer chemotherapy.

[26]  P. Bouillet,et al.  Gene structure, alternative splicing, and chromosomal localization of pro-apoptotic Bcl-2 relative Bim , 2001, Mammalian Genome.

[27]  J. Melo,et al.  The molecular biology of chronic myeloid leukemia. , 2000, Blood.

[28]  J. Griffin,et al.  Bcr/Abl activates transcription of the Bcl-X gene through STAT5. , 2000, Blood.

[29]  C. Print,et al.  The proapoptotic BH3-only protein bim is expressed in hematopoietic, epithelial, neuronal, and germ cells. , 2000, The American journal of pathology.

[30]  E. Andreu,et al.  Blockade of the Bcr-Abl Kinase Activity Induces Apoptosis of Chronic Myelogenous Leukemia Cells by Suppressing Signal Transducer and Activator of Transcription 5–Dependent Expression of Bcl-XL , 2000, The Journal of experimental medicine.

[31]  J. Griffin,et al.  STAT5 activation contributes to growth and viability in Bcr/Abl-transformed cells. , 2000, Blood.

[32]  J. Spivak,et al.  Commentary on and reprint of Nowell PC, Hungerford DA, A minute chromosome in human chronic granulocytic leukemia, in Science (1960) 132:1497 , 2000 .

[33]  C. Eaves,et al.  Autocrine production and action of IL-3 and granulocyte colony-stimulating factor in chronic myeloid leukemia. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[34]  B. Calabretta,et al.  Signal Transducer and Activator of  Transcription (STAT)5 Activation by BCR/ABL Is Dependent on Intact Src Homology (SH)3 and SH2 Domains of BCR/ABL and Is Required for Leukemogenesis , 1999, The Journal of Experimental Medicine.

[35]  A. Strasser,et al.  The proapoptotic activity of the Bcl-2 family member Bim is regulated by interaction with the dynein motor complex. , 1999, Molecular cell.

[36]  D. Green,et al.  Bcl-2-independent Bcr–Abl-mediated resistance to apoptosis: protection is correlated with up regulation of Bcl-xL , 1998, Oncogene.

[37]  A. Strasser,et al.  Bim: a novel member of the Bcl‐2 family that promotes apoptosis , 1998, The EMBO journal.

[38]  B. Calabretta,et al.  Transformation of hematopoietic cells by BCR/ABL requires activation of a PI‐3k/Akt‐dependent pathway , 1997, The EMBO journal.

[39]  Luigi Naldini,et al.  Multiply attenuated lentiviral vector achieves efficient gene delivery in vivo , 1997, Nature Biotechnology.

[40]  B. Zehnbauer,et al.  Inhibition of apoptosis by BCR-ABL in chronic myeloid leukemia. , 1994, Blood.

[41]  T Pawson,et al.  Bcr‐Abl oncoproteins bind directly to activators of the Ras signalling pathway. , 1994, The EMBO journal.

[42]  Nanxin Li,et al.  BCR-ABL-induced oncogenesis is mediated by direct interaction with the SH2 domain of the GRB-2 adaptor protein , 1993, Cell.

[43]  P. Chomczyński,et al.  One-hour downward alkaline capillary transfer for blotting of DNA and RNA. , 1992, Analytical biochemistry.

[44]  G. Daley,et al.  Transformation of an interleukin 3-dependent hematopoietic cell line by the chronic myelogenous leukemia-specific P210bcr/abl protein. , 1988, Proceedings of the National Academy of Sciences of the United States of America.

[45]  T. Chou,et al.  Quantitative analysis of dose-effect relationships: the combined effects of multiple drugs or enzyme inhibitors. , 1984, Advances in enzyme regulation.

[46]  J. Stephenson,et al.  A cellular oncogene is translocated to the Philadelphia chromosome in chronic myelocytic leukaemia , 1982, Nature.

[47]  J. Rowley.  A New Consistent Chromosomal Abnormality in Chronic Myelogenous Leukaemia identified by Quinacrine Fluorescence and Giemsa Staining , 1973, Nature.

[48]  P. Nowell,et al.  A minute chromosome in human chronic granulocytic leukemia , 1960 .