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Sarvaiya PJ, Schwartz JR, Geng CD, Vedeckis WV. c-Myb interacts with the glucocorticoid receptor and regulates its level in pre-B-acute lymphoblastic leukemia cells. Mol Cell Endocrinol 2012; 361:124-32. [PMID: 22516378 PMCID: PMC3404235 DOI: 10.1016/j.mce.2012.03.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 03/21/2012] [Accepted: 03/30/2012] [Indexed: 01/30/2023]
Abstract
Glucocorticoid (GC) hormones are used in the treatment of hematopoietic malignancies. When the GC binds to the glucocorticoid receptor (GR) protein, c-Myb and GR are recruited at the Glucocorticoid Response Unit in the DNA. Here we demonstrate that c-Myb interacts with the GR and that decreasing c-Myb amounts reduces the levels of GR transcripts and protein in 697 pre-B-acute lymphoblastic leukemia (ALL) cells. Furthermore, the auto-upregulation of GR promoter 1C and promoter 1D is blunted at reduced c-Myb levels. Taken together, these data show that c-Myb is a direct, key regulator of the GR. Unexpectedly, the reduction in c-Myb levels increased the sensitivity of the cells to steroid-mediated apoptosis. This was because the reduction in c-Myb itself decreases cell viability, and the residual GR remained above the threshold needed to trigger apoptosis. These studies show the mutual importance of c-Myb and the GR in controlling survival of pre-B ALL cells.
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Affiliation(s)
| | | | | | - Wayne V. Vedeckis
- Corresponding Author and to whom reprint requests should be addressed: Wayne V. Vedeckis, Ph.D,. Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1901 Perdido Street, New Orleans, Louisiana 70112, Phone #: 504-568-8175, Fax #: 504-568-6697,
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2
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Jin S, Zhao H, Yi Y, Nakata Y, Kalota A, Gewirtz AM. c-Myb binds MLL through menin in human leukemia cells and is an important driver of MLL-associated leukemogenesis. J Clin Invest 2010; 120:593-606. [PMID: 20093773 DOI: 10.1172/jci38030] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Accepted: 11/23/2009] [Indexed: 01/01/2023] Open
Abstract
Mixed-lineage leukemia (MLL) is a proto-oncogene frequently involved in chromosomal translocations associated with acute leukemia. These chromosomal translocations commonly result in MLL fusion proteins that dysregulate transcription. Recent data suggest that the MYB proto-oncogene, which is an important regulator of hematopoietic cell development, has a role in leukemogenesis driven by the MLL-ENL fusion protein, but exactly how is unclear. Here we have demonstrated that c-Myb is recruited to the MLL histone methyl transferase complex by menin, a protein important for MLL-associated leukemic transformation, and that it contributes substantially to MLL-mediated methylation of histone H3 at lysine 4 (H3K4). Silencing MYB in human leukemic cell lines and primary patient material evoked a global decrease in H3K4 methylation, an unexpected decrease in HOXA9 and MEIS1 gene expression, and decreased MLL and menin occupancy in the HOXA9 gene locus. This decreased occupancy was associated with a diminished ability of an MLL-ENL fusion protein to transform normal mouse hematopoietic cells. Previous studies have shown that MYB expression is regulated by Hoxa9 and Meis1, indicating the existence of an autoregulatory feedback loop. The finding that c-Myb has the ability to direct epigenetic marks, along with its participation in an autoregulatory feedback loop with genes known to transform hematopoietic cells, lends mechanistic and translationally relevant insight into its role in MLL-associated leukemogenesis.
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Affiliation(s)
- Shenghao Jin
- Division of Hematology/Oncology, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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3
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Transcriptional repression of c-Myb and GATA-2 is involved in the biologic effects of C/EBPalpha in p210BCR/ABL-expressing cells. Blood 2008; 112:1942-50. [PMID: 18550858 DOI: 10.1182/blood-2007-09-114975] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Ectopic C/EBPalpha expression in p210(BCR/ABL)-expressing hematopoietic cells induces granulocytic differentiation, inhibits proliferation, and suppresses leukemogenesis. To assess the underlying mechanisms, C/EBPalpha targets were identified by microarray analyses. Upon C/EBPalpha activation, expression of c-Myb and GATA-2 was repressed in 32D-BCR/ABL, K562, and chronic myelogenous leukemia (CML) blast crisis (BC) primary cells but only c-Myb levels decreased slightly in CD34(+) normal progenitors. The role of these 2 genes for the effects of C/EBPalpha was assessed by perturbing their expression in K562 cells. Ectopic c-Myb expression blocked the proliferation inhibition- and differentiation-inducing effects of C/EBPalpha, whereas c-Myb siRNA treatment enhanced C/EBPalpha-mediated proliferation inhibition and induced changes in gene expression indicative of monocytic differentiation. Ectopic GATA-2 expression suppressed the proliferation inhibitory effect of C/EBPalpha but blocked in part the effect on differentiation; GATA-2 siRNA treatment had no effects on C/EBPalpha induction of differentiation but inhibited proliferation of K562 cells, alone or upon C/EBPalpha activation. In summary, the effects of C/EBPalpha in p210(BCR/ABL)-expressing cells depend, in part, on transcriptional repression of c-Myb and GATA-2. Since perturbation of c-Myb and GATA-2 expression has nonidentical consequences for proliferation and differentiation of K562 cells, the effects of C/EBPalpha appear to involve dif-ferent transcription-regulated targets.
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4
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Fisher RC, Slayton WB, Chien C, Guthrie SM, Bray C, Scott EW. PU.1 supports proliferation of immature erythroid progenitors. Leuk Res 2004; 28:83-9. [PMID: 14630084 DOI: 10.1016/s0145-2126(03)00178-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Despite normal levels of erythropoiesis in PU.1(-/-) embryos, PU.1(-/-) fetal hematopoietic progenitors are unable to establish sustained erythropoiesis in the adult bone marrow. This study demonstrates that PU.1(-/-) fetal erythroid progenitors are synergistically expanded by TPO plus SCF, but not combinations of EPO plus SCF, IL-3 or GM-CSF. The EPO defect is not corrected by a constitutively active variant of EPOR. Microarray analysis identified several candidate PU.1 target genes known to affect cytokine signaling and gene regulation in the erythroid lineage. These data suggest that PU.1 plays an important role in regulating the proliferation of immature erythroid progenitors.
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Affiliation(s)
- Robert C Fisher
- Program in Stem Cell Biology and Regenerative Medicine, Shands Cancer Center, Department of Molecular Genetics and Microbiology, Box 100232, Room R4-293, University of Florida, Gainesville, FL 32610, USA.
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5
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Salesse S, Verfaillie CM. BCR/ABL: from molecular mechanisms of leukemia induction to treatment of chronic myelogenous leukemia. Oncogene 2002; 21:8547-59. [PMID: 12476301 DOI: 10.1038/sj.onc.1206082] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
MESH Headings
- Antineoplastic Agents/therapeutic use
- Fusion Proteins, bcr-abl
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/physiopathology
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/metabolism
- Signal Transduction/drug effects
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Affiliation(s)
- Stephanie Salesse
- Stem Cell Institute, Cancer Center and Department of Medicine, University of Minnesota Cancer Center, Minneapolis, Minnesota, MN 55455, USA
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6
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Abstract
The BCR-ABL oncogene is essential to the pathogenesis of chronic myelogenous leukemia, and immune mechanisms play an important role in control of this disease. Understanding of the molecular pathogenesis of chronic myelogenous leukemia has led to the development of several novel therapies, which can be broadly divided into therapies based on 1) inhibition of the BCR-ABL oncogene expression, 2) inhibition of other genes important to the pathogenesis of chronic myelogenous leukemia, 3) inhibition of BCR-ABL protein function, and 4) immunomodulation. We have systematically reviewed each of these novel therapeutic approaches in this article.
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MESH Headings
- Alkyl and Aryl Transferases/antagonists & inhibitors
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- Benzamides
- Cancer Vaccines/therapeutic use
- Cell Transformation, Neoplastic/genetics
- Clinical Trials, Phase II as Topic
- Clinical Trials, Phase III as Topic
- Drug Resistance, Neoplasm/genetics
- Enzyme Inhibitors/therapeutic use
- Farnesyltranstransferase
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/physiology
- Genes, myb
- Hematopoietic Stem Cell Transplantation
- Humans
- Imatinib Mesylate
- Immunotherapy, Adoptive
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/therapy
- Methotrexate/pharmacology
- Models, Biological
- Multicenter Studies as Topic
- Neoplasm Proteins/metabolism
- Oligonucleotides, Antisense/pharmacology
- Oligonucleotides, Antisense/therapeutic use
- Phosphorylation
- Piperazines/pharmacology
- Piperazines/therapeutic use
- Protein Processing, Post-Translational
- Pyrimidines/pharmacology
- Pyrimidines/therapeutic use
- RNA, Messenger/antagonists & inhibitors
- RNA, Neoplasm/antagonists & inhibitors
- Signal Transduction/drug effects
- Tetrahydrofolate Dehydrogenase/genetics
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Affiliation(s)
- B N Jahagirdar
- Stem Cell Institute, Division of Hematology-Oncology and Transplantation, University of Minnesota, Minneapolis, Minn 55455, USA
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7
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Gewirtz AM. Methodologic approaches for investigating human megakaryocyte development at a molecular level. Stem Cells 2001; 14 Suppl 1:206-11. [PMID: 11012223 DOI: 10.1002/stem.5530140727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Rapid advances in defining the extracellular regulators of megakaryocyte (MK) development have heightened interest in defining the biochemical and molecular mechanisms of action of these cytokines. The recent development of molecular micromethodologies such as in situ hybridization, the polymerase chain reaction, and the use of antisense oligodeoxynucleotides now make such studies possible in normal cells. To illustrate the utility of these methods, data gathered using these methods on developing normal human hematopoietic cells and MKs is presented. As might be expected, the results obtained demonstrate that growth factors have complex time and concentration effects on gene expression in morphologically recognizable human MKs. They also suggest that a more complete understanding of normal MK development at the molecular level will soon be possible.
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Affiliation(s)
- A M Gewirtz
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia 19104, USA
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Manzella L, Gualdi R, Perrotti D, Nicolaides NC, Girlando G, Giuffrida MA, Messina A, Calabretta B. The interferon regulatory factors 1 and 2 bind to a segment of the human c-myb first intron: possible role in the regulation of c-myb expression. Exp Cell Res 2000; 256:248-56. [PMID: 10739671 DOI: 10.1006/excr.1999.4794] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The preferential expression of the protooncogene c-myb in hematopoietic cells is in part regulated by a mechanism of transcriptional block in the first intron. By electrophoresis mobility shift assays using probes corresponding to different segments of the putative human c-myb intron 1 transcription pause region and nuclear extracts from myeloid leukemia HL 60 and fibroblast WI 38 cells, we detected a HL-60-specific DNA-protein complex with a 123-bp fragment containing binding sites for the interferon regulatory factors (IRFs) nuclear proteins. Formation of the DNA-protein complex was abrogated by competition with an oligomer containing the wild-type, but not the mutated, IRF binding site and the complex was specifically supershifted by the anti-IRF-1 or the anti-IRF-2 antibody. Moreover, in vitro translated IRF-1 or IRF-2 protein did interact with the 123-bp c-myb intron 1 fragment. Upon TPA-induced differentiation, c-myb expression was readily down-modulated in parental HL 60 cells, but not in cells transfected with an antisense IRF-1 plasmid. Moreover, chloramphenicol acetyltransferase activity driven by a c-myb promoter containing the entire intron 1 was suppressed upon IRF-1, but not IRF-2 expression. Together, these results are consistent with the existence of a functional relationship between IRF-1 and c-myb in which IRF-1 negatively regulates c-myb expression at the transcriptional level by a mechanism that may depend on the interaction of IRF-1 with a segment of the c-myb gene implicated in transcription pausing.
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Affiliation(s)
- L Manzella
- Department of Microbiology and Immunology and Kimmel Cancer Institute, Thomas Jefferson University, Bluemle Life Sciences Building, 233 South 10th Street, Philadelphia, Pennsylvania 19107, USA
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Agarwal N, Gewirtz AM. Oligonucleotide therapeutics for hematologic disorders. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1489:85-96. [PMID: 10806999 DOI: 10.1016/s0167-4781(99)00142-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
During the last decade, the catalogue of known genes responsible for cell growth, development, and neoplastic transformation has expanded dramatically. Attempts to translate this information into new therapeutic strategies for both hematologic and non-hematologic diseases have accelerated at a rapid pace as well. Inserting genes into cells which either replace, or counter the effects of disease causing genes has been one of the primary ways in which scientists have tried to exploit this new knowledge. Strategies to directly downregulate gene expression have developed in parallel with this approach. The latter include triple helix forming oligonucleotides (ODN) and 'antisense' ODN. The latter have already entered clinical trials for a variety of disorders. In this monograph, we review the use of these materials in the treatment of hematologic diseases, particularly myelogenous leukemias. Problems and possible solutions associated with the use of ODN will be discussed as well.
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MESH Headings
- Animals
- Blood Coagulation Disorders/drug therapy
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/genetics
- Hematologic Diseases/drug therapy
- Humans
- Leukemia, Experimental/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myeloid, Acute/drug therapy
- Lymphoma, Non-Hodgkin/drug therapy
- Mice
- Mice, SCID
- Oligonucleotides/therapeutic use
- Oligonucleotides, Antisense/therapeutic use
- Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors
- Proto-Oncogene Proteins c-bcl-2/genetics
- Proto-Oncogene Proteins c-myb/antagonists & inhibitors
- Proto-Oncogene Proteins c-myb/genetics
- Proto-Oncogene Proteins c-myc/antagonists & inhibitors
- Proto-Oncogene Proteins c-myc/genetics
- RNA, Messenger/antagonists & inhibitors
- Signal Transduction/drug effects
- Tumor Suppressor Protein p53/antagonists & inhibitors
- Tumor Suppressor Protein p53/genetics
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Affiliation(s)
- N Agarwal
- Department of Internal Medicine, University of Pennsylvania School of Medicine, Philadelphia, USA
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10
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Abstract
High levels of c-myb expression are necessary for the proliferation of hematopoietic precursor cells whereas down-regulation of c-myb is required for terminal differentiation; this down-regulation occurs through a conditional block to transcriptional elongation in intron I. We previously observed that cAMP analogs prevented the late down-regulation of c-myb during hexamethylene bisacetamide (HMBA)-induced differentiation of murine erythroleukemia (MEL) cells and blocked differentiation; this correlated with the induction of NF-kappaB (p50/RelB) complexes which were shown to bind to NF-kappaB recognition sites flanking the transcriptional pause site of c-myb. We now selected stably-transfected MEL cells which overexpressed p50, RelB or both at levels similar to those induced by cAMP to determine whether these NF-kappaB proteins regulate c-myb expression in intact cells. We demonstrate that transcriptionally active NF-kappaB (p50/RelB) complexes, but not p50 or RelB alone, prevented the early and late down-regulation of c-myb mRNA and increased c-myb transcriptional elongation in HMBA-induced MEL cells. The increase in c-myb expression was sufficient to block erythroid differentiation and allow continuous proliferation of cells in the presence of HMBA. Steady-state c-myb mRNA levels in untreated cells were not affected by overexpression of NF-kappaB, suggesting that p50/RelB specifically modulated the efficiency of transcriptional attenuation during MEL cell differentiation.
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Affiliation(s)
- M Suhasini
- Department of Medicine and Cancer Center, University of California, San Diego, La Jolla, California, CA 92037-0652, USA
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11
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The 3rd Annual NIH Symposium on Therapeutic Oligonucleotides. Bethesda, Maryland, USA. December 4, 1998. Abstracts. ANTISENSE & NUCLEIC ACID DRUG DEVELOPMENT 1999; 9:359-431. [PMID: 10498436 DOI: 10.1089/oli.1.1999.9.359] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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12
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Abstract
For the past several years, we have been engaged in developing a therapeutically effective strategy for disrupting gene function with reverse complementary, or so called 'antisense', oligodeoxynucleotides (ODN). This pursuit has focused on finding appropriate diseases in which to apply this approach, and suitable gene targets. Of the genes that we have targeted for disruption using the antisense ODN strategy (Clevenger et al., 1995; Gewirtz and Calabretta, 1988; Ratajczak et al., 1992c; Small et al., 1994) one that has been of particular interest, and one where therapeutically motivated disruptions are now in clinical trial, is the myb gene (reviewed in Lyon et al., 1994). These trials involve treatment of human leukemias. These diseases are a logical choice for developing oncogene targeted therapies because of easy access to tissues, and the abundance of knowledge about the cell and molecular biology of these diseases. Nevertheless, as will be touched on below, other malignancies have also been examined as models for Myb targeted therapy with some surprisingly encouraging results. Finally, while we have focused our efforts on the ODN strategy, I will allude briefly to other strategies for disrupting Myb function with therapeutic intent.
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Affiliation(s)
- A M Gewirtz
- Department of Internal Medicine, Institute for Human Gene Therapy, University of Pennsylvania School of Medicine, Philadelphia 19104, USA
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13
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Gewirtz AM. The c-myb Protooncogene: A Novel Target for Human Gene Therapy. Gene Ther 1999. [DOI: 10.1007/978-3-0348-7011-5_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bcl-3 Expression and Nuclear Translocation Are Induced by Granulocyte-Macrophage Colony-Stimulating Factor and Erythropoietin in Proliferating Human Erythroid Precursors. Blood 1998. [DOI: 10.1182/blood.v92.4.1225] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractBcl-3 is a proto-oncogene involved in the chromosomal translocation t(14;19) found in some patients with chronic lymphocytic leukemia. It shares structural similarities with and is a member of the IκB family of proteins. In this report, involvement of Bcl-3in hematopoietic growth factor-stimulated erythroid proliferation and differentiation was examined. In TF-1 cells, an erythroleukemia cell line, granulocyte-macrophage colony-stimulating factor (GM-CSF) and erythropoietin (Epo) greatly enhanced Bcl-3 expression at both the protein and mRNA levels in association with stimulation of proliferation. Bcl-3 protein was also highly expressed in early burst-forming unit-erythroid (BFU-E)–derived erythroid precursors (day 7) and decreased during maturation (days 10 and 14), suggesting that Bcl-3 is involved in normal erythroid proliferation. In these hematopoietic cells, Bcl-3 was hyperphosphorylated. GM-CSF and Epo modulated the subcellular localization of Bcl-3. Upon stimulation of TF-1 cells with GM-CSF or Epo, the nuclear translocation ofBcl-3 was dramatically enhanced. Overexpression of Bcl-3 in TF-1 cells by transient transfection along with the NF-κB factors p50 or p52 resulted in significant induction of an human immunodeficiency virus–type 1 (HIV-1) κB-TATA-luceriferase reporter plasmid, demonstrating that Bcl-3 has a positive role in transactivation of κB-containing genes in erythroid cells. Stimulation with GM-CSF enhanced c-myb mRNA expression in these cells. Bcl-3 in nuclear extracts of TF-1 cells bound to a κB enhancer in the c-mybpromoter together with NF-κB2/p52 and this binding activity was enhanced by GM-CSF stimulation. Furthermore, cotransfection of Bcl-3 with p52 or p50 in TF-1 cells resulted in significant activation of ac-myb κB-TATA-luceriferase reporter plasmid. These findings suggest that Bcl-3 may participate in the transcriptional regulation of certain κB-containing genes involved in hematopoiesis, includingc-myb.© 1998 by The American Society of Hematology.
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Bcl-3 Expression and Nuclear Translocation Are Induced by Granulocyte-Macrophage Colony-Stimulating Factor and Erythropoietin in Proliferating Human Erythroid Precursors. Blood 1998. [DOI: 10.1182/blood.v92.4.1225.416k20_1225_1234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bcl-3 is a proto-oncogene involved in the chromosomal translocation t(14;19) found in some patients with chronic lymphocytic leukemia. It shares structural similarities with and is a member of the IκB family of proteins. In this report, involvement of Bcl-3in hematopoietic growth factor-stimulated erythroid proliferation and differentiation was examined. In TF-1 cells, an erythroleukemia cell line, granulocyte-macrophage colony-stimulating factor (GM-CSF) and erythropoietin (Epo) greatly enhanced Bcl-3 expression at both the protein and mRNA levels in association with stimulation of proliferation. Bcl-3 protein was also highly expressed in early burst-forming unit-erythroid (BFU-E)–derived erythroid precursors (day 7) and decreased during maturation (days 10 and 14), suggesting that Bcl-3 is involved in normal erythroid proliferation. In these hematopoietic cells, Bcl-3 was hyperphosphorylated. GM-CSF and Epo modulated the subcellular localization of Bcl-3. Upon stimulation of TF-1 cells with GM-CSF or Epo, the nuclear translocation ofBcl-3 was dramatically enhanced. Overexpression of Bcl-3 in TF-1 cells by transient transfection along with the NF-κB factors p50 or p52 resulted in significant induction of an human immunodeficiency virus–type 1 (HIV-1) κB-TATA-luceriferase reporter plasmid, demonstrating that Bcl-3 has a positive role in transactivation of κB-containing genes in erythroid cells. Stimulation with GM-CSF enhanced c-myb mRNA expression in these cells. Bcl-3 in nuclear extracts of TF-1 cells bound to a κB enhancer in the c-mybpromoter together with NF-κB2/p52 and this binding activity was enhanced by GM-CSF stimulation. Furthermore, cotransfection of Bcl-3 with p52 or p50 in TF-1 cells resulted in significant activation of ac-myb κB-TATA-luceriferase reporter plasmid. These findings suggest that Bcl-3 may participate in the transcriptional regulation of certain κB-containing genes involved in hematopoiesis, includingc-myb.© 1998 by The American Society of Hematology.
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Abstract
NF-κB/Rel designates a widely distributed family of transcription factors involved in immune and acute phase responses. Here, the expression and function of NF-κB factors in erythroid proliferation and differentiation were explored. In an erythroleukemia cell line, TF-1, high levels of p105/p50, p100/p52, p65, and IκBα were detected 24 hours after growth factor deprivation. In response to granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation, significant induction of p52 expression was observed. GM-CSF also induced nuclear translocation of both p52 and p65. No induction of NF-κB factors was observed with erythropoietin stimulation of TF-1 cells. Overexpression of p52 and p65 in TF-1 cells by transient transfection resulted in significant induction of a κB-TATA-luciferase reporter plasmid, showing that these factors are functional in vivo in erythroid cells. To determine whether NF-κB factors may play a role in normal erythropoiesis, levels of these factors were determined in burst-forming unit-erythroid (BFU-E)–derived cells at different stages of differentiation. The NF-κB factors p105/p50, p100/p52, and p65 were highly expressed in early BFU-E–derived precursors, which are rapidly proliferating, and declined during maturation. Furthermore, nuclear levels of NF-κB factors p50, p52, and p65 were higher in less mature precursors (day 10 BFU-E–derived cells) compared with more differentiated (day 14) erythroblasts. In nuclear extracts from day 10 BFU-E–derived cells, p50, p52, and p65 were able to form complexes, which bound to κB sites in the promoters of both the c-myb and c-mycgenes, suggesting that c-myb and c-myc may be among the κB-containing genes regulated by NF-κB factors in normal erythroid cells. Taken together, these data show that NF-κB factors are modulated by GM-CSF and suggest they function to regulate specific κB containing genes involved in erythropoiesis.
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Abstract
Abstract
NF-κB/Rel designates a widely distributed family of transcription factors involved in immune and acute phase responses. Here, the expression and function of NF-κB factors in erythroid proliferation and differentiation were explored. In an erythroleukemia cell line, TF-1, high levels of p105/p50, p100/p52, p65, and IκBα were detected 24 hours after growth factor deprivation. In response to granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation, significant induction of p52 expression was observed. GM-CSF also induced nuclear translocation of both p52 and p65. No induction of NF-κB factors was observed with erythropoietin stimulation of TF-1 cells. Overexpression of p52 and p65 in TF-1 cells by transient transfection resulted in significant induction of a κB-TATA-luciferase reporter plasmid, showing that these factors are functional in vivo in erythroid cells. To determine whether NF-κB factors may play a role in normal erythropoiesis, levels of these factors were determined in burst-forming unit-erythroid (BFU-E)–derived cells at different stages of differentiation. The NF-κB factors p105/p50, p100/p52, and p65 were highly expressed in early BFU-E–derived precursors, which are rapidly proliferating, and declined during maturation. Furthermore, nuclear levels of NF-κB factors p50, p52, and p65 were higher in less mature precursors (day 10 BFU-E–derived cells) compared with more differentiated (day 14) erythroblasts. In nuclear extracts from day 10 BFU-E–derived cells, p50, p52, and p65 were able to form complexes, which bound to κB sites in the promoters of both the c-myb and c-mycgenes, suggesting that c-myb and c-myc may be among the κB-containing genes regulated by NF-κB factors in normal erythroid cells. Taken together, these data show that NF-κB factors are modulated by GM-CSF and suggest they function to regulate specific κB containing genes involved in erythropoiesis.
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Abstract
The protooncogene c-myb is a nuclear transcription factor that shares significant sequence homology with two other myb family members, A-myb and B-myb. Recent studies have suggested that c-myb is involved in regulation of the cell cycle via control of intracellular calcium [Ca2+]i concentration. Given the limited cell type expression of the c-myb gene, we set out to investigate whether myb-dependent cell cycle regulation occurs in cells not known to express the c-myb protein. NIH 3T3 fibroblasts were stably transfected with an inducible c-myb dominant negative construct composed of a myb DNA binding domain linked to the Drosophila engrailed transcription suppresser (pGREMEn) and a full-length murine c-myb cDNA sequence. Induced expression of the dominant negative construct was associated with a G1 cell cycle arrest and a failure to increase late G1 intracellular calcium levels. Similar expression studies in mouse embryonic fibroblasts derived from the c-myb knockout mouse have demonstrated lower baseline [Ca2+]i levels than in normal mice fibroblasts that were not further lowered by MEn expression. We conclude that regulation of calcium homeostasis and cell cycle progression via myb-dependent transcription may play an important role in cells not possessing detectable levels of c-myb protein.
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Affiliation(s)
- K Bein
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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21
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Granulocytic Differentiation of Normal Hematopoietic Precursor Cells Induced by Transcription Factor PU.1 Correlates With Negative Regulation of the c-myb Promoter. Blood 1997. [DOI: 10.1182/blood.v90.5.1828] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractNumerous transcription factors allow hematopoietic cells to respond to lineage- and stage-specific cytokines and/or to act as their effectors. The transcription factors PU.1 and c-Myb are essential for hematopoiesis, most likely acting at distinct stages of differentiation, but sharing a common set of target genes. To determine whether PU.1 and c-Myb are functionally interrelated, murine bone marrow (BM) cells and 32Dcl3 murine myeloid precursor cells were infected with a retrovirus carrying a PU.1 cDNA and assessed for myeloid colony formation and for granulocytic differentiation, respectively. Compared with noninfected normal BM cells or to cells infected with an empty virus, hematopoietic precursor cells expressing PU.1 formed an increased number of interleukin-3 (IL-3) and granulocyte colony-stimulating factor (G-CSF )–stimulated colonies. Moreover, granulocytic differentiation of 32Dcl3 cells constitutively expressing PU.1 was accelerated, as indicated by morphology and by expression of differentiation markers. Downregulation of c-Myb protein levels by expression of an antisense c-myb construct was also associated with a faster kinetics of 32Dcl3 granulocytic differentiation. Sequence analysis of the 5′ flanking region of the c-myb gene revealed a consensus PU box at position +16 to +21 able to specifically interact in electrophoretic mobility shift assays with either bacterially synthesized PU.1 protein or whole cell extracts from differentiated 32Dcl3 cells. Transient expression of PU.1 in cotransfection assays in different cell lines resulted in inhibition of chloramphenicol acetyl transferase activity driven by different segments of the c-myb promoter. Moreover, such an effect was dependent on an intact PU box. Thus, the ability of PU.1 to potentiate terminal myeloid differentiation appears to involve downregulation of c-myb expression, an essential step during differentiation of hematopoietic precursor cells.
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22
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Piccinini G, Luchetti MM, Caniglia ML, Carossino AM, Montroni M, Introna M, Gabrielli A. c-myb proto-oncogene is expressed by quiescent scleroderma fibroblasts and, unlike B-myb gene, does not correlate with proliferation. J Invest Dermatol 1996; 106:1281-6. [PMID: 8752671 DOI: 10.1111/1523-1747.ep12348998] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Systemic sclerosis (scleroderma) is characterized by excessive deposition of extracellular matrix constituents. Although it has been proposed that tissue fibrosis is due to increased fibroblast synthesis of various collagen polypeptides, there is some experimental evidence that patients with systemic sclerosis have a defect in the control of fibroblast growth. The myb family of genes includes, among others, the c-myb proto-oncogene and the structurally related gene, B-myb, which are both implicated in the regulation of differentiation and/or proliferation of hematopoietic and nonhematopoietic cells. To elucidate the molecular basis responsible for scleroderma fibroblast proliferation, we therefore elected to investigate the expression of c-myb and B-myb genes in scleroderma and control cells. Using the reverse transcriptase polymerase chain reaction technique, we detected c-myb transcripts in scleroderma skin fibroblasts rendered quiescent by serum deprivation. Under the same experimental conditions, c-myb message was not found in normal skin fibroblasts, but, after serum stimulation, c-myb RNA was clearly evident from 3 to 72 h in both normal and pathologic cells. Treatment of these cells with c-myb antisense oligonucleotides caused downregulation of c-myb expression, and the inhibition of scleroderma fibroblast proliferation was 42%, whereas in normal fibroblasts the inhibition was weaker (22%). In contrast to c-myb, in normal and scleroderma fibroblasts the level of expression of B-myb correlated with cell proliferation assessed by cell count, and densitometric analysis showed that B-myb message was 1.5-5 times higher in most of pathologic cells studied. The antisense B-myb oligonucleotides had a weaker antiproliferative effect compared with antisense c-myb, inhibiting scleroderma and normal fibroblasts by 23% and 13%, respectively. These data suggest that the B-myb and c-myb genes may play a role in scleroderma fibroblast proliferation and function.
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Affiliation(s)
- G Piccinini
- Institute of Internal Medicine, Haematology and Clinical Immunology, University of Ancona, Ancona, Italy
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23
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Gryaznov S, Skorski T, Cucco C, Nieborowska-Skorska M, Chiu CY, Lloyd D, Chen JK, Koziolkiewicz M, Calabretta B. Oligonucleotide N3'-->P5' phosphoramidates as antisense agents. Nucleic Acids Res 1996; 24:1508-14. [PMID: 8628685 PMCID: PMC145826 DOI: 10.1093/nar/24.8.1508] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Uniformly modified oligonucleotide N3'-->P5' phosphoramidates, where every 3'-oxygen is replaced by a 3'-amino group, were synthesized. These compounds have very high affinity to single-stranded RNAs and thus have potential utility as antisense agents. As was shown in this study, the oligonucleotide phosphoramidates are resistant to digestion with snake venom phosphodiesterase, to nuclease activity in a HeLa cell nuclear extract, or to nuclease activity in 50% human plasma, where no significant hydrolysis was observed after 8 h. These compounds were used in various in vitro cellular systems as antisense compounds addressed to different targeted regions of c-myb, c-myc and bcr-abl mRNAs. C-myb antisense phosphoramidates at 5 microM caused sequence and dose-dependent inhibition of HL-60 cell proliferation and a 75% reduction in c-myb protein and RNA levels, as determined by Western blot and RT-PCR analysis. Analogous results were observed for anti-c-myc phosphoramidates, where a complete cytostatic effect for HL-60 cells was observed at 1 microM concentration for fully complementary, but not for mismatched compounds, which were indistinguishable from untreated controls. This was correlated with a 93% reduction in c-myc protein level. Moreover, colony formation by the primary CML cells was also inhibited 75-95% and up to 99% by anti-c-myc and anti-bcr-abl phosphoramidate oligonucleotides, respectively, in a sequence- and dose-dependent manner within a 0.5 nM-5 microM dose range. At these concentrations the colony-forming ability of normal bone marrow cells was not affected. The presented in vitro data indicate that oligonucleotide N3'-->P5' phosphoramidates could be used as specific and efficient antisense agents.
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Affiliation(s)
- S Gryaznov
- Lynx Therapeutics, Inc., Hayward, CA 94545, USA
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24
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Affiliation(s)
- A M Gewirtz
- University of Pennsylvania, School of Medicine, Department of Pathology, Philadelphia 19104-6082, USA
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25
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Skorski T, Nieborowska-Skorska M, Campbell K, Iozzo RV, Zon G, Darzynkiewicz Z, Calabretta B. Leukemia treatment in severe combined immunodeficiency mice by antisense oligodeoxynucleotides targeting cooperating oncogenes. J Exp Med 1995; 182:1645-53. [PMID: 7500009 PMCID: PMC2192227 DOI: 10.1084/jem.182.6.1645] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Transformation of hematopoietic cells by the p210bcr/abl tyrosine kinase appears to require the expression of a functional MYC protein, suggesting that simultaneous targeting of BCR-ABL and c-myc might be a rational strategy for attempting treatment of Phil-adelphia leukemia. To test this hypothesis, severe combined immunodeficiency mice injected with Philadelphia leukemic cells were treated systemically with equal doses of bcr-abl or c-myc antisense oligodeoxynucleotides (ODNs) or with both ODNs in combination. Compared with the mice treated with individual agents, the disease process was much slower in the group treated with both ODNs, as revealed by flow cytometry, clonogenic assay, and reverse transcriptase-polymerase chain reaction analysis to detect leukemic cells in mouse tissue cell suspensions, and by enumeration of liver metastases. The retardation of the disease process was positively correlated with a markedly increased survival of leukemic mice treated with both ODNs. These data demonstrate the therapeutic potential of targeting multiple cooperating oncogenes.
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MESH Headings
- Animals
- Base Sequence
- DNA Primers/chemistry
- Fusion Proteins, bcr-abl/genetics
- Gene Expression
- Genes, myc
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Male
- Mice
- Mice, SCID
- Molecular Sequence Data
- Neoplasm Metastasis
- Neprilysin/analysis
- Oligonucleotides, Antisense/therapeutic use
- Oncogenes
- RNA, Messenger/genetics
- RNA, Neoplasm/genetics
- Tumor Cells, Cultured
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Affiliation(s)
- T Skorski
- Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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26
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Perrotti D, Melotti P, Skorski T, Casella I, Peschle C, Calabretta B. Overexpression of the zinc finger protein MZF1 inhibits hematopoietic development from embryonic stem cells: correlation with negative regulation of CD34 and c-myb promoter activity. Mol Cell Biol 1995; 15:6075-87. [PMID: 7565760 PMCID: PMC230859 DOI: 10.1128/mcb.15.11.6075] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Zinc finger genes encode proteins that act as transcription factors. The myeloid zinc finger 1 (MZF1) gene encodes a zinc finger protein with two DNA-binding domains that recognize two distinct consensus sequences, is preferentially expressed in hematopoietic cells, and may be involved in the transcriptional regulation of hematopoiesis-specific genes. Reverse transcription-PCR analysis of human peripheral blood CD34+ cells cultured under lineage-restricted conditions demonstrated MZF1 expression during both myeloid and erythroid differentiation. Sequence analysis of the 5'-flanking region of the CD34 and c-myb genes, which are a marker of and a transcriptional factor required for hematopoietic proliferation and differentiation, respectively, revealed closely spaced MZF1 consensus binding sites found by electrophoretic mobility shift assays to interact with recombinant MZF1 protein. Transient or constitutive MZF1 expression in different cell types resulted in specific inhibition of chloramphenicol acetyltransferase activity driven by the CD34 or c-myb 5'-flanking region. To determine whether transcriptional modulation by MZF1 activity plays a role in hematopoietic differentiation, constructs containing the MZF1 cDNA under the control of different promoters were transfected into murine embryonic stem cells which, under defined in vitro culture conditions, generate colonies of multiple hematopoietic lineages. Constitutive MZF1 expression interfered with the ability of embryonic stem cells to undergo hematopoietic commitment and erythromyeloid colony formation and prevented the induced expression of CD34 and c-myb mRNAs during differentiation of these cells. These data indicate that MZF1 plays a critical role in hematopoiesis by modulating the expression of genes involved in this process.
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Affiliation(s)
- D Perrotti
- Department of Microbiology and Immunology, Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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27
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Affiliation(s)
- M A Kirkland
- Leukaemia Research Fund Centre for Adult Leukaemia, Royal Postgraduate Medical School, London
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28
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Migliaccio AR, Migliaccio G, Mancini G, Ratajczak M, Gewirtz AM, Adamson JW. Induction of the murine "W phenotype" in long-term cultures of human cord blood cells by c-kit antisense oligomers. J Cell Physiol 1993; 157:158-63. [PMID: 7691834 DOI: 10.1002/jcp.1041570120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The murine white (W) spotting locus is the site of the c-kit gene and encodes a tyrosine kinase receptor while the complementary Steel (Sl) locus encodes its ligand. Mutations at either locus have profound effects on hematopoiesis, particularly erythroid and mast cell proliferation. We added c-kit antisense oligonucleotides to long-term suspension cultures of enriched human umbilical cord progenitor cells. This resulted in the suppression of c-kit gene expression and the preferential suppression of the generation of erythroid burst-forming cells (BFU-E) which extended over the life of the culture (3 weeks). The results provide an in vitro model of the "W phenotype" in human hematopoiesis and confirm the importance of c-kit gene function in early erythropoiesis. Because the generation of BFU-E was suppressed even after c-kit gene expression had recovered, this gene product may be critical to the erythroid commitment process.
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Affiliation(s)
- A R Migliaccio
- Lindsley F. Kimball Research Institute, New York Blood Center, New York 10021
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29
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Abstract
As the cell and molecular biology of hematopoietic cell development becomes known in greater detail, the roles of individual genes in regulating cell proliferation and growth also become better appreciated. Some genes appear to be of particular importance in these complex processes and are therefore potential targets for molecularly based therapeutics. The rationale for such treatment is that, if the function of critical genes can be efficiently and specifically perturbed, then the ensuing disruption might lead to preferential leukemic cell death. Several technologies for carrying out targeted gene disruption now exist. One approach, the "antisense" gene strategy, appears to be particularly well suited to the treatment of human leukemia ex vivo and perhaps in vivo as well. Herein I review the experience of my laboratory in using this approach to target the c-myb and c-kit proto-oncogenes in human leukemic cells. Our results suggest that use of oligodeoxynucleotides for disrupting the function of specific genes may prove useful for both ex vivo and in vivo treatment of patients with hematopoietic malignancies.
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MESH Headings
- Animals
- Base Sequence
- Cell Line
- Clone Cells/drug effects
- Fusion Proteins, bcr-abl/pharmacology
- Hematopoietic Stem Cells/drug effects
- Humans
- Leukemia, Erythroblastic, Acute/drug therapy
- Leukemia, Erythroblastic, Acute/pathology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Mice
- Molecular Sequence Data
- Oligodeoxyribonucleotides/genetics
- Oligodeoxyribonucleotides/therapeutic use
- Proto-Oncogene Proteins/pharmacology
- Proto-Oncogene Proteins c-kit
- Proto-Oncogene Proteins c-myb
- Receptor Protein-Tyrosine Kinases/pharmacology
- Receptors, Colony-Stimulating Factor
- Tumor Stem Cell Assay
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Affiliation(s)
- A M Gewirtz
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia 19104
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30
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Szczylik C, Skorski T, Ku DH, Nicolaides NC, Wen SC, Rudnicka L, Bonati A, Malaguarnera L, Calabretta B. Regulation of proliferation and cytokine expression of bone marrow fibroblasts: role of c-myb. J Exp Med 1993; 178:997-1005. [PMID: 7688794 PMCID: PMC2191153 DOI: 10.1084/jem.178.3.997] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The c-myb protooncogene plays a major role in regulating the process of in vitro and in vivo hematopoiesis via its activity as transcriptional regulator in hematopoietic progenitor cells. Since the bone marrow microenvironment appears to regulate in vivo hematopoiesis by maintaining the growth of multipotent progenitors via secretion of specific cytokines, we asked whether c-myb is also required for the proliferation of and/or cytokine production by stromal cells that generate fibroblast-like colonies (fibroblast colony-forming units [CFU-F]). Using the reverse transcriptase polymerase chain reaction technique, we detected low levels of c-myb mRNA transcripts in human normal bone marrow fibroblasts. Treatment of these cells with c-myb antisense oligodeoxynucleotides caused downregulation of c-myb expression, decreased in the number of marrow CFU-F colonies (approximately 54% inhibition) and in the cell number within residual colonies (approximately 80%), and downregulation of granulocyte/macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF) mRNA expression. Transfection of T98G glioblastoma cells, in which expression of c-myb, GM-CSF, and SCF mRNAs is undetectable or barely detectable, with a plasmid containing a full-length c-myb cDNA under the control of the SV40 promoter induced the expression of biologically active SCF and GM-CSF in these cells. Regulation of GM-CSF expression by c-myb was due in part to transactivation of the GM-CSF promoter. These results indicate that, in addition to regulating hematopoietic cell proliferation, c-myb is also required for proliferation of and cytokines synthesis by bone marrow fibroblasts.
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Affiliation(s)
- C Szczylik
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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31
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Calabretta B, Venturelli D, Gewirtz AM. Functional significance of c-myb expression in normal and leukemic hematopoiesis. Cancer Invest 1993; 11:191-7. [PMID: 8462020 DOI: 10.3109/07357909309024839] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- B Calabretta
- Department of Microbiology, Thomas Jefferson University, Philadelphia, PA 19107
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32
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Gewirtz AM. Potential therapeutic applications of antisense oligodeoxynucleotides in the treatment of chronic myelogenous leukemia. Leuk Lymphoma 1993; 11 Suppl 1:131-7. [PMID: 7504543 DOI: 10.3109/10428199309047876] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Chronic myelogenous leukemia (CML) cell growth may be inhibited by exposure to antisense (AS) oligodeoxynucleotides (ODN). Our initial studies targeted the c-myb protooncogene and were carried out on cells derived from patients in CML blast crisis. Subsequently, we extended these studies to cells isolated from patients in chronic disease phase. We found that c-myb AS ODN inhibited growth of CML CFU-GM in a dose dependent, sequence specific manner in approximately 75% of cases evaluated. Bcr-abl expression was either greatly decreased or nondetectable in the residual colonies and no residual leukemic CFU were demonstrable upon re-plating of treated cells. AS ODN that target the c-kit protooncogene also inhibit CML CFU and lead to downregulation of bcr-abl in responding cells in approximately 50% of cases. Therefore, AS ODN may prove to be useful purging agents. Most recently, we have treated SCID mice engrafted with bcr-abl expressing human K562 cell leukemia with phosphorothioate modified AS ODN. We have found that treated mice survive three to eight times longer than their untreated or sense treated controls. In aggregate, these results suggest that AS ODN may prove useful for both ex vivo and in vivo treatment of patients with CML.
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MESH Headings
- Animals
- Base Sequence
- Blast Crisis/pathology
- Drug Screening Assays, Antitumor
- Female
- Fusion Proteins, bcr-abl/genetics
- Humans
- Leukemia, Erythroblastic, Acute/pathology
- Leukemia, Erythroblastic, Acute/therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/therapy
- Leukemia, Myeloid, Chronic-Phase/pathology
- Mice
- Mice, SCID
- Molecular Sequence Data
- Neoplasm Proteins/antagonists & inhibitors
- Neoplasm Proteins/genetics
- Neoplasm Transplantation
- Oligonucleotides, Antisense/pharmacology
- Oligonucleotides, Antisense/therapeutic use
- Proto-Oncogene Proteins/antagonists & inhibitors
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins c-kit
- Proto-Oncogene Proteins c-myb
- Receptor Protein-Tyrosine Kinases/antagonists & inhibitors
- Receptor Protein-Tyrosine Kinases/genetics
- Receptors, Colony-Stimulating Factor/antagonists & inhibitors
- Receptors, Colony-Stimulating Factor/genetics
- Thionucleotides/therapeutic use
- Tumor Cells, Cultured
- Tumor Stem Cell Assay
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Affiliation(s)
- A M Gewirtz
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia 19104
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33
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Gewirtz AM, Shapiro C, Shen YM, Boyd R, Colman RW. Cellular and molecular regulation of factor V expression in human megakaryocytes. J Cell Physiol 1992; 153:277-87. [PMID: 1429848 DOI: 10.1002/jcp.1041530207] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The mechanisms responsible for regulating FV expression in normal human megakaryocytes are unknown. To test the hypothesis that they are related to cell maturation events, we correlated human megakaryocyte FV antigen content with several putative maturation markers including cell size, morphologic stage of development, and ploidy level. Mature megakaryocytes were isolated from normal marrow by counterflow centrifugal elutriation. The cells were immunofluorescently labeled with a monoclonal antibody probe (B10) directed against the FV connecting peptide (150 kDa) and then reacted with Chromomycin A3 to allow for simultaneous DNA quantitation in the same cell. After processing, individual cells were stages and sized. FV antigen and nuclear DNA levels (ploidy) were measured by microphotometric measurements of total cytoplasmic or nuclear fluorescence. A total of 1,006 cells were examined, of which 12% were stage I, 8% were stage II, 35% were stage III, and 45% were stage IV. The geometric mean diameter (+/- SD) of cells in these stages was 48.3 +/- 11.8 microns2, 54.9 +/- 14.4 microns2, 61.7 +/- 20.02 microns2, and 56.7 +/- 13.2 microns2, respectively. Respective ploidy values in arbitrary fluorescence units, where 2 N = 5%, were 28.2 +/- 18.2%, 31.4 +/- 19.3%, 54.3 +/- 26.6%, and 33.2 +/- 22.7%. Calculated correlation coefficients (r) and coefficient of determination (r2) values suggested that FV antigen levels varied independently of any of the maturation markers studied. However, FV antigen levels could be upregulated by 24 h exposure to 8 nM phorbol myristate acetate (PMA). Presence of FV mRNA in a pure population of megakaryocytes was demonstrated by in situ hybridization and the polymerase chain reaction. Relative levels of megakaryocyte FV mRNA, as assessed by in situ hybridization, failed to reveal a detectable change after PMA exposure in spite of an increase in detectable protein. These data suggest that FV synthesis may be regulated at the post-transcriptional level and that it is subject to regulatory influences which are not coordinately linked to development of other terminal maturation markers.
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Affiliation(s)
- A M Gewirtz
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia 19104
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34
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Sala A, Calabretta B. Regulation of BALB/c 3T3 fibroblast proliferation by B-myb is accompanied by selective activation of cdc2 and cyclin D1 expression. Proc Natl Acad Sci U S A 1992; 89:10415-9. [PMID: 1438227 PMCID: PMC50349 DOI: 10.1073/pnas.89.21.10415] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The B-myb gene is expressed in many cell types at the G1/S transition of the cell cycle. Inhibition of B-myb expression in BALB/c 3T3 fibroblasts by introduction of a B-myb antisense construct greatly diminished cell proliferation, whereas constitutive expression of a human B-myb cDNA in these cells reduced their growth factor requirements and induced a transformed phenotype. Constitutive expression of B-myb cDNA was accompanied by activation of cyclin D1 and cdc2 expression but not of cyclin A and cyclin B. Transfection of BALB/B-myb cells (a cell line expressing high levels of exogenous human B-myb) with a cyclin D1 antisense construct drastically reduced cloning efficiency of these cells. These results suggest that the B-myb-encoded product regulates fibroblast proliferation by activating cdc2 and cyclin D1 gene expression and that abnormal expression of cyclin D1 might be a step in the process of transformation.
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Affiliation(s)
- A Sala
- Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, PA 19107
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35
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Ferrari S, Manfredini R, Grande A, Torelli U. Antisense strategies to characterize the role of genes and oncogenes involved in myeloid differentiation. Ann N Y Acad Sci 1992; 660:11-26. [PMID: 1340115 DOI: 10.1111/j.1749-6632.1992.tb21053.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- S Ferrari
- Experimental Hematology Center, II Medical Clinic, University of Modena, Italy
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36
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Calabretta B, Skorski T, Szczylik C, Caracciolo D, Valtieri M, Venturelli D. Protooncogenes in the regulation of normal hematopoiesis. An antisense approach. Ann N Y Acad Sci 1992; 660:117-23. [PMID: 1285069 DOI: 10.1111/j.1749-6632.1992.tb21064.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- B Calabretta
- Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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37
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Affiliation(s)
- A M Gewirtz
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia 19104
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38
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The Jun family members, c-Jun and JunD, transactivate the human c-myb promoter via an Ap1-like element. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41826-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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39
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Citro G, Perrotti D, Cucco C, D'Agnano I, Sacchi A, Zupi G, Calabretta B. Inhibition of leukemia cell proliferation by receptor-mediated uptake of c-myb antisense oligodeoxynucleotides. Proc Natl Acad Sci U S A 1992; 89:7031-5. [PMID: 1495997 PMCID: PMC49639 DOI: 10.1073/pnas.89.15.7031] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Exposure of human leukemia HL-60 cells to an oligodeoxynucleotide complementary to an 18-base sequence (codons 2-7) of c-myb-encoded mRNA has previously been shown to result in inhibition of cell proliferation. Because HL-60 cells express high levels of transferrin receptor we adapted a DNA delivery system based on receptor-mediated endocytosis to introduce myb oligomers complexed with a transferrin-polylysine conjugate into those cells. A DNA.RNA duplex resistant to S1 nuclease digestion was detected as early as 12 hr after culture of HL-60 cells in the presence of the myb antisense/transferrin-polylysine complex. Exposure of HL-60 cells to the myb antisense/transferrin-polylysine complex resulted in rapid and profound inhibition of proliferation and loss of cell viability much more pronounced than that occurring in cells exposed to free myb antisense oligodeoxynucleotides. The transferrin-polylysine/myb sense complex or the transferrin-polylysine conjugate alone had no effect on HL-60 cell proliferation and viability. These findings indicate that myb synthetic oligodeoxynucleotides enter efficiently into HL-60 by transferrin receptor-mediated endocytosis and exert a profound biological effect. Such a delivery system could exploit other ligand-receptor interactions for the selective delivery of oncogene-targeted antisense oligodeoxynucleotides.
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MESH Headings
- Antineoplastic Agents/metabolism
- Antineoplastic Agents/pharmacology
- Base Sequence
- Cell Division/drug effects
- Cell Line
- DNA, Neoplasm/isolation & purification
- DNA, Neoplasm/metabolism
- Drug Carriers
- Fluorescent Antibody Technique
- Humans
- Leukemia, Promyelocytic, Acute
- Molecular Sequence Data
- Oligonucleotides, Antisense/metabolism
- Oligonucleotides, Antisense/pharmacology
- Oncogenes
- Polylysine/chemical synthesis
- RNA, Messenger/genetics
- RNA, Neoplasm/isolation & purification
- RNA, Neoplasm/metabolism
- Receptors, Transferrin/metabolism
- Transferrin/chemical synthesis
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Affiliation(s)
- G Citro
- Laboratorio Chemioterapia Sperimentale, Istituto Tumori Regina Elena, Rome, Italy
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40
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Ratajczak MZ, Luger SM, DeRiel K, Abrahm J, Calabretta B, Gewirtz AM. Role of the KIT protooncogene in normal and malignant human hematopoiesis. Proc Natl Acad Sci U S A 1992; 89:1710-4. [PMID: 1371882 PMCID: PMC48522 DOI: 10.1073/pnas.89.5.1710] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The role of the KIT protooncogene in human hematopoiesis is uncertain. Therefore, we examined KIT mRNA expression in normal human bone marrow mononuclear cells (MNC) and used antisense oligodeoxynucleotides (oligomers) to disrupt KIT function. KIT mRNA was detected with certainty only in growth factor-stimulated MNC. Expression was essentially abrogated by making MNC quiescent or by inhibiting myb gene function. Oligomers blocked KIT mRNA expression in a dose-response and sequence-specific manner, thereby allowing functional examination of the KIT receptor. In experiments with either partially purified or CD34(+)-enriched MNC, neither granulocyte nor megakaryocyte colony formation was inhibited by oligomer exposure. In contrast, KIT antisense oligomers inhibited interleukin 3/erythropoietin-driven erythroid colony formation approximately 70% and "stem cell factor"/erythropoietin-driven colony formation 100%. The presence of erythroid progenitor cell subsets with differential requirements for KIT function is therefore suggested. Growth of hematopoietic colonies from chronic myeloid leukemia and polycythemia vera patients was also inhibited, while acute leukemia colony growth appeared less sensitive to KIT deprivation. These results suggest that KIT plays a predominant role in normal erythropoiesis but may be important in regulating some types of malignant hematopoietic cell growth as well. They also suggest that KIT expression is linked to cell metabolic activity and that its expression may be regulated by or coregulated with MYB.
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Affiliation(s)
- M Z Ratajczak
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia 19104
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41
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Graf T. Myb: a transcriptional activator linking proliferation and differentiation in hematopoietic cells. Curr Opin Genet Dev 1992; 2:249-55. [PMID: 1638119 DOI: 10.1016/s0959-437x(05)80281-3] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Myb is a transcriptional activator protein with repeated helix-turn-helix DNA-binding motifs distantly related to the homeodomain. In hematopoiesis, c-myb appears to control both cell proliferation and differentiation. The mechanisms by which the leukemogenic potential of c-Myb is activated are complex and involve truncations, point mutations, and fusion or coexpression with other proteins.
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Affiliation(s)
- T Graf
- Differentiation Programme, European Molecular Biology Laboratory, Heidelberg, Germany
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42
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Skorski T, Szczylik C, Ratajczak MZ, Malaguarnera L, Gewirtz AM, Calabretta B. Growth factor-dependent inhibition of normal hematopoiesis by N-ras antisense oligodeoxynucleotides. J Exp Med 1992; 175:743-50. [PMID: 1371302 PMCID: PMC2119161 DOI: 10.1084/jem.175.3.743] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
To determine whether N-ras expression is required at specific stages of the process of in vitro normal human hematopoiesis, adherent- and T lymphocyte-depleted mononuclear marrow cells (A-T-MNC) or highly purified progenitors (CD34+ cells) were cultured in semisolid medium, under conditions that favor the growth of specific progenitor cell types, after exposure to N-ras sense and antisense oligodeoxynucleotides. N-ras antisense, but not sense, oligodeoxynucleotide treatment of A-T-MNC and CD34+ cells resulted in a significantly decreased number of granulocyte/macrophage colony-forming units (CFU-GM) induced by interleukin 3 (IL-3) or granulocyte/macrophage colony-stimulating factor (GM-CSF) and of macrophage colonies (CFU-M) induced by M-CSF, but not of granulocytic colonies induced with G-CSF or IL-5. However, the same treatment significantly inhibited colony formation induced by each of the above factors in combination with IL-3. Megakaryocytic colony (CFU-Meg) formation from A-T-MNC or CD34+ cells in the presence of IL-6 + IL-3 + erythropoietin (Epo) was also markedly decreased after antisense oligodeoxynucleotide treatment. Erythroid colonies derived from A-T-MNC in the presence of Epo (CFU-E) were not inhibited upon antisense treatment, whereas those arising from A-T-MNC or CD34+ cells in the presence of IL-3 + Epo (BFU-E) were markedly affected. These results are consistent with the hypothesis that distinct signal transduction pathways, involving N-ras or not, are activated by different growth factors in different hematopoietic progenitor cells.
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Affiliation(s)
- T Skorski
- Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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44
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Abstract
Retroviruses are known to carry specific genes that are likely to be responsible for induction of the malignant phenotype in the cells they infect. These genes, termed viral oncogenes (v-onc), have subsequently been shown to be derived from highly conserved, normal cellular genes commonly referred to as proto-oncogenes (c-onc). Proto-oncogenes are thought to be intimately involved in the processes of cell proliferation and differentiation. Therefore, any c-onc amplification, mutation, structural alteration, or change in transcriptional regulation might lead to, or be associated with, induction of a malignant phenotype. Targeted disruption of these genes may therefore be of therapeutic value. We discuss the role of antisense DNA in carrying out such therapy.
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Affiliation(s)
- N Hijiya
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia 19104
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45
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Positive autoregulation of c-myb expression via Myb binding sites in the 5' flanking region of the human c-myb gene. Mol Cell Biol 1991. [PMID: 1944282 DOI: 10.1128/mcb.11.12.6166] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The nuclear proto-oncogene c-myb is preferentially expressed in lymphohematopoietic cells, in which it plays an important role in the processes of differentiation and proliferation. The mechanism(s) that regulates c-myb expression is not fully understood, although in mouse cells a regulatory mechanism involves a transcriptional block in the first intron. To analyze the contribution of the 5' flanking sequences in regulating the expression of the human c-myb gene, we isolated a genomic clone containing extensive 5' flanking sequences, the first exon, and a large portion of the first intron. Sequence analysis of a subcloned 1.3-kb BamHI insert corresponding to 687 nucleotides of the 5' flanking sequence, the entire first exon, and 300 nucleotides of the first intron revealed the presence of closely spaced putative Myb binding sites within a segment extending from nucleotides -616 to -575 upstream from the cap site. A 165-bp segment containing these putative Myb binding sites was linked to a human thymidine kinase (TK) cDNA driven by a low-activity proliferating cell nuclear antigen promoter and cotransfected into TK- ts13 cells with a plasmid in which a full-length human c-myb cDNA is driven by the early simian virus 40 promoter; Myb inducibility of TK mRNA expression was observed both in transient expression assays and in stable transformants. The highest level of inducibility was detected when the 165-bp fragment was placed 138 bp upstream of the proliferating cell nuclear antigen promoter-TK cDNA reporter unit or 3' of the TK cDNA. Mutation of the putative Myb binding sites greatly reduced c-myb transactivation of TK mRNA expression and specifically reduced the binding of in vitro-translated Myb protein at those sites. Finally, c-myb transactivated TK mRNA expression driven by a segment of the authentic c-myb 5' flanking region containing the Myb binding sites. These data suggest that human c-myb maintains high levels of Myb protein in cells that require this gene product for proliferation and/or differentiation by an autoregulatory mechanism involving Myb binding sites in the 5' flanking region.
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46
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Nicolaides NC, Gualdi R, Casadevall C, Manzella L, Calabretta B. Positive autoregulation of c-myb expression via Myb binding sites in the 5' flanking region of the human c-myb gene. Mol Cell Biol 1991; 11:6166-76. [PMID: 1944282 PMCID: PMC361795 DOI: 10.1128/mcb.11.12.6166-6176.1991] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The nuclear proto-oncogene c-myb is preferentially expressed in lymphohematopoietic cells, in which it plays an important role in the processes of differentiation and proliferation. The mechanism(s) that regulates c-myb expression is not fully understood, although in mouse cells a regulatory mechanism involves a transcriptional block in the first intron. To analyze the contribution of the 5' flanking sequences in regulating the expression of the human c-myb gene, we isolated a genomic clone containing extensive 5' flanking sequences, the first exon, and a large portion of the first intron. Sequence analysis of a subcloned 1.3-kb BamHI insert corresponding to 687 nucleotides of the 5' flanking sequence, the entire first exon, and 300 nucleotides of the first intron revealed the presence of closely spaced putative Myb binding sites within a segment extending from nucleotides -616 to -575 upstream from the cap site. A 165-bp segment containing these putative Myb binding sites was linked to a human thymidine kinase (TK) cDNA driven by a low-activity proliferating cell nuclear antigen promoter and cotransfected into TK- ts13 cells with a plasmid in which a full-length human c-myb cDNA is driven by the early simian virus 40 promoter; Myb inducibility of TK mRNA expression was observed both in transient expression assays and in stable transformants. The highest level of inducibility was detected when the 165-bp fragment was placed 138 bp upstream of the proliferating cell nuclear antigen promoter-TK cDNA reporter unit or 3' of the TK cDNA. Mutation of the putative Myb binding sites greatly reduced c-myb transactivation of TK mRNA expression and specifically reduced the binding of in vitro-translated Myb protein at those sites. Finally, c-myb transactivated TK mRNA expression driven by a segment of the authentic c-myb 5' flanking region containing the Myb binding sites. These data suggest that human c-myb maintains high levels of Myb protein in cells that require this gene product for proliferation and/or differentiation by an autoregulatory mechanism involving Myb binding sites in the 5' flanking region.
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Affiliation(s)
- N C Nicolaides
- Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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47
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Mitjavila MT, Le Couedic JP, Casadevall N, Navarro S, Villeval JL, Dubart A, Vainchenker W. Autocrine stimulation by erythropoietin and autonomous growth of human erythroid leukemic cells in vitro. J Clin Invest 1991; 88:789-97. [PMID: 1653276 PMCID: PMC295463 DOI: 10.1172/jci115378] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Autonomous colony formation is a frequent event in erythroleukemia. In 13 cases of early erythroid leukemias, we investigated whether erythropoietin (Epo) autocrine stimulation was responsible for the growth factor autonomy. Epo transcripts were detected by Northern blotting in cells from one patient. These cells also expressed an Epo receptor (1,000 receptors per cell) with a 420-pM affinity and Epo was detected in the supernatant of cultured cells. In 8 of the 13 cases, Epo transcripts were revealed by the polymerase chain reaction ranging from 0.5 to 500 copies per cell. In situ hybridization proved that these Epo transcripts were present in the blast cells. No Epo gene abnormalities were detected by Southern blotting. In two cases, leukemic cells were grown in the presence of Epo-neutralizing antibodies or Epo antisense oligomers. In one case, the antibody significantly reduced autonomous growth. In contrast, the antibody had no effect in the second case in which blast cells transcribed the Epo gene at a low level. However, Epo antisense oligomers partially inhibited autonomous growth. This inhibition was reversed by addition of exogenous Epo. Overall, these results suggest that an extracellular or intracellular autocrine Epo stimulation occurs in some cases of erythroid malignancies.
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Affiliation(s)
- M T Mitjavila
- Institut National de la Santé et de la Recherche Médicale (INSERM) U 91, Hôpital Henri-Mondor, Créteil, France
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48
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Szczylik C, Skorski T, Nicolaides NC, Manzella L, Malaguarnera L, Venturelli D, Gewirtz AM, Calabretta B. Selective inhibition of leukemia cell proliferation by BCR-ABL antisense oligodeoxynucleotides. Science 1991; 253:562-5. [PMID: 1857987 DOI: 10.1126/science.1857987] [Citation(s) in RCA: 280] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To determine the role of the BCR-ABL gene in the proliferation of blast cells of patients with chronic myelogenous leukemia, leukemia blast cells were exposed to synthetic 18-mer oligodeoxynucleotides complementary to two identified BCR-ABL junctions. Leukemia colony formation was suppressed, whereas granulocyte-macrophage colony formation from normal marrow progenitors was unaffected. When equal proportions of normal marrow progenitors and blast cells were mixed, exposed to the oligodeoxynucleotides, and assayed for residual colony formation, the majority of residual cells were normal. These findings demonstrate the requirement for a functional BCR-ABL gene in maintaining the leukemic phenotype and the feasibility of gene-targeted selective killing of neoplastic cells.
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MESH Headings
- Base Sequence
- Blast Crisis/genetics
- Blast Crisis/pathology
- Cell Division/drug effects
- Exons
- Fusion Proteins, bcr-abl/genetics
- Gene Expression/drug effects
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Molecular Sequence Data
- Monocytes/cytology
- Monocytes/drug effects
- Oligonucleotides, Antisense/pharmacology
- Oncogenes
- RNA, Messenger/analysis
- RNA, Messenger/genetics
- Tumor Cells, Cultured/cytology
- Tumor Cells, Cultured/drug effects
- Tumor Stem Cell Assay
- beta 2-Microglobulin/genetics
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Affiliation(s)
- C Szczylik
- Department of Pathology, Temple University Medical School, Philadelphia, PA 19140
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49
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Affiliation(s)
- A M Gewirtz
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia 19140
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50
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Calabretta B, Sims RB, Valtieri M, Caracciolo D, Szczylik C, Venturelli D, Ratajczak M, Beran M, Gewirtz AM. Normal and leukemic hematopoietic cells manifest differential sensitivity to inhibitory effects of c-myb antisense oligodeoxynucleotides: an in vitro study relevant to bone marrow purging. Proc Natl Acad Sci U S A 1991; 88:2351-5. [PMID: 2006173 PMCID: PMC51229 DOI: 10.1073/pnas.88.6.2351] [Citation(s) in RCA: 152] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The c-myb protooncogene is preferentially expressed in hematopoietic cells, and its encoded protein, Myb, is required for hematopoietic cell proliferation. To analyze the relative Myb dependence of normal and leukemic human hematopoietic progenitor cells, normal bone marrow cells, several types of leukemic blast cells, and 1:1 mixtures of normal and leukemic cells were cultured in the presence of c-myb sense or antisense oligodeoxynucleotides; cell viability and cloning efficiency were then assessed. c-myb sense oligomers had negligible effects on normal and leukemic cells. In contrast, c-myb antisense oligomers strongly inhibited or completely abolished clonogenic growth of a T-cell leukemia line, 78% (18 of 23) of primary acute myelogenous leukemia cases examined, and 4 of 5 primary chronic myelogenous leukemia (CML) cases in blast crisis. In three of the latter patients, polymerase chain reaction analysis of a 1:1 mixture of c-myb antisense-treated normal and CML cells revealed a complete absence of bcr-abl expression, suggesting that the CML clonogenic units had been completely eliminated from the cultures. At antisense doses that inhibited leukemic cell growth, normal hematopoietic progenitor cells survived. Thus, normal and leukemic hematopoietic cells show differential sensitivity to the toxic effects of c-myb antisense DNA. Perturbation of c-myb function with antisense oligodeoxynucleotides might eventually form the basis for a molecular approach to leukemia therapy, perhaps most immediately as ex vivo bone marrow purging agents.
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Affiliation(s)
- B Calabretta
- Department of Pathology, Temple University School of Medicine, Philadelphia, PA 19140
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