Unlike its Paralog LEDGF/p75, HRP-2 Is Dispensable for MLL-R Leukemogenesis but Important for Leukemic Cell Survival

HDGF-related protein 2 (HRP-2) is a member of the Hepatoma-Derived Growth Factor-related protein family that harbors the structured PWWP and Integrase Binding Domain, known to associate with methylated histone tails or cellular and viral proteins, respectively. Interestingly, HRP-2 is a paralog of Lens Epithelium Derived Growth Factor p75 (LEDGF/p75), which is essential for MLL-rearranged (MLL-r) leukemia but dispensable for hematopoiesis. Sequel to these findings, we investigated the role of HRP-2 in hematopoiesis and MLL-r leukemia. Protein interactions were investigated by co-immunoprecipitation and validated using recombinant proteins in NMR. A systemic knockout mouse model was used to study normal hematopoiesis and MLL-ENL transformation upon the different HRP-2 genotypes. The role of HRP-2 in MLL-r and other leukemic, human cell lines was evaluated by lentiviral-mediated miRNA targeting HRP-2. We demonstrate that MLL and HRP-2 interact through a conserved interface, although this interaction proved less dependent on menin than the MLL-LEDGF/p75 interaction. The systemic HRP-2 knockout mice only revealed an increase in neutrophils in the peripheral blood, whereas the depletion of HRP-2 in leukemic cell lines and transformed primary murine cells resulted in reduced colony formation independently of MLL-rearrangements. In contrast, primary murine HRP-2 knockout cells were efficiently transformed by the MLL-ENL fusion, indicating that HRP-2, unlike LEDGF/p75, is dispensable for the transformation of MLL-ENL leukemogenesis but important for leukemic cell survival.

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Cannabis-induced cytotoxicity in leukemic cell lines: the role of the cannabinoid receptors and the MAPK pathway

Blood ◽

10.1182/blood-2004-03-1182 ◽

2005 ◽

Vol 105 (3) ◽

pp. 1214-1221 ◽

Cited By ~ 48

Author(s):

Thomas Powles ◽

Robert te Poele ◽

Jonathan Shamash ◽

Tracy Chaplin ◽

David Propper ◽

...

Keyword(s):

Signal Transduction ◽

Cell Death ◽

Cell Lines ◽

Leukemic Cell ◽

Cytotoxic Agents ◽

Complex Signal ◽

Signal Transduction Pathways ◽

Potent Inducer ◽

Leukemic Cell Lines

Abstract Δ9-Tetrahydrocannabinol (THC) is the active metabolite of cannabis. THC causes cell death in vitro through the activation of complex signal transduction pathways. However, the role that the cannabinoid 1 and 2 receptors (CB1-R and CB2-R) play in this process is less clear. We therefore investigated the role of the CB-Rs in mediating apoptosis in 3 leukemic cell lines and performed microarray and immunoblot analyses to establish further the mechanism of cell death. We developed a novel flow cytometric technique of measuring the expression of functional receptors and used combinations of selective CB1-R and CB2-R antagonists and agonists to determine their individual roles in this process. We have shown that THC is a potent inducer of apoptosis, even at 1 × IC50 (inhibitory concentration 50%) concentrations and as early as 6 hours after exposure to the drug. These effects were seen in leukemic cell lines (CEM, HEL-92, and HL60) as well as in peripheral blood mononuclear cells. Additionally, THC did not appear to act synergistically with cytotoxic agents such as cisplatin. One of the most intriguing findings was that THC-induced cell death was preceded by significant changes in the expression of genes involved in the mitogen-activated protein kinase (MAPK) signal transduction pathways. Both apoptosis and gene expression changes were altered independent of p53 and the CB-Rs.

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Constitutive Activation of the JAK2/STAT5 Signal Transduction Pathway Correlates With Growth Factor Independence of Megakaryocytic Leukemic Cell Lines

Blood ◽

10.1182/blood.v93.7.2369 ◽

1999 ◽

Vol 93 (7) ◽

pp. 2369-2379 ◽

Cited By ~ 47

Author(s):

Richard Y. Liu ◽

Chun Fan ◽

Roy Garcia ◽

Richard Jove ◽

Kenneth S. Zuckerman

Keyword(s):

Signal Transduction ◽

Cell Proliferation ◽

Growth Factor ◽

Dna Binding ◽

Cell Lines ◽

Leukemic Cell ◽

Constitutive Activation ◽

Leukemic Cell Lines ◽

Binding Factor ◽

Hel Cells

Abstract The factor-independent Dami/HEL and Meg-01 and factor-dependent Mo7e leukemic cell lines were used as models to investigate JAK/STAT signal transduction pathways in leukemic cell proliferation. Although Dami/HEL and Meg-01 cell proliferation in vitro was independent of and unresponsive to exogenous cytokines including granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), IL-6, thrombopoietin (TPO), and tumor necrosis factor- (TNF-), the growth of Mo7e cells was dependent on hematopoietic growth factors. When these cell lines were cultured in medium without cytokines, a constitutively activated STAT-like DNA-binding factor was detected in nuclear extracts from both Dami/HEL and Meg-01 cells. However, the STAT-like factor was not detectable in untreated Mo7e cells, but was activated transiently in Mo7e cells in response to cytokine treatments. The constitutively activated and cytokine-induced STAT-like DNA-binding factor in these three cell lines was identified as STAT5 by oligonucleotide competition gel mobility assays and by specific anti-STAT antibody gel supershift assays. Constitutive activation of JAK2 also was detected in the factor-independent cell lines, but not in Mo7e cells without cytokine exposure. Meg-01 cells express a p185 BCR/ABL oncogene, which may be responsible for the constitutive activation of STAT5. Dami/HEL cells do not express the BCR/ABL oncogene, but increased constitutive phosphorylation of Raf-1 oncoprotein was detected. In cytokine bioassays using growth factor-dependent Mo7e and TF-1 cells as targets, conditioned media from Dami/HEL and Meg-01 cells did not show stimulatory effects on cell proliferation. Our results indicate that the constitutive activation of JAK2/STAT5 correlates with the factor-independent growth of Dami/HEL and Meg-01 cells. The constitutive activation of JAK2/STAT5 in Dami/HEL cells is triggered by a mechanism other than autocrine cytokines or the BCR/ABL oncoprotein.

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Constitutive Activation of the JAK2/STAT5 Signal Transduction Pathway Correlates With Growth Factor Independence of Megakaryocytic Leukemic Cell Lines

Blood ◽

10.1182/blood.v93.7.2369.407k18_2369_2379 ◽

1999 ◽

Vol 93 (7) ◽

pp. 2369-2379 ◽

Cited By ~ 4

Author(s):

Richard Y. Liu ◽

Chun Fan ◽

Roy Garcia ◽

Richard Jove ◽

Kenneth S. Zuckerman

Keyword(s):

Signal Transduction ◽

Cell Proliferation ◽

Growth Factor ◽

Dna Binding ◽

Cell Lines ◽

Leukemic Cell ◽

Constitutive Activation ◽

Leukemic Cell Lines ◽

Binding Factor ◽

Hel Cells

The factor-independent Dami/HEL and Meg-01 and factor-dependent Mo7e leukemic cell lines were used as models to investigate JAK/STAT signal transduction pathways in leukemic cell proliferation. Although Dami/HEL and Meg-01 cell proliferation in vitro was independent of and unresponsive to exogenous cytokines including granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), IL-6, thrombopoietin (TPO), and tumor necrosis factor- (TNF-), the growth of Mo7e cells was dependent on hematopoietic growth factors. When these cell lines were cultured in medium without cytokines, a constitutively activated STAT-like DNA-binding factor was detected in nuclear extracts from both Dami/HEL and Meg-01 cells. However, the STAT-like factor was not detectable in untreated Mo7e cells, but was activated transiently in Mo7e cells in response to cytokine treatments. The constitutively activated and cytokine-induced STAT-like DNA-binding factor in these three cell lines was identified as STAT5 by oligonucleotide competition gel mobility assays and by specific anti-STAT antibody gel supershift assays. Constitutive activation of JAK2 also was detected in the factor-independent cell lines, but not in Mo7e cells without cytokine exposure. Meg-01 cells express a p185 BCR/ABL oncogene, which may be responsible for the constitutive activation of STAT5. Dami/HEL cells do not express the BCR/ABL oncogene, but increased constitutive phosphorylation of Raf-1 oncoprotein was detected. In cytokine bioassays using growth factor-dependent Mo7e and TF-1 cells as targets, conditioned media from Dami/HEL and Meg-01 cells did not show stimulatory effects on cell proliferation. Our results indicate that the constitutive activation of JAK2/STAT5 correlates with the factor-independent growth of Dami/HEL and Meg-01 cells. The constitutive activation of JAK2/STAT5 in Dami/HEL cells is triggered by a mechanism other than autocrine cytokines or the BCR/ABL oncoprotein.

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Constitutive and inducible secretion of platelet-derived growth factor analogs by human leukemic cell lines coexpressing erythroid and megakaryocytic markers.

Journal of Clinical Investigation ◽

10.1172/jci112895 ◽

1987 ◽

Vol 79 (3) ◽

pp. 859-866 ◽

Cited By ~ 53

Author(s):

T Papayannopoulou ◽

E Raines ◽

S Collins ◽

B Nakamoto ◽

M Tweeddale ◽

...

Keyword(s):

Growth Factor ◽

Cell Lines ◽

Leukemic Cell ◽

Platelet Derived Growth Factor ◽

Human Leukemic Cell ◽

Leukemic Cell Lines

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Synergy between Transforming Growth Factor-? and Tumor Necrosis Factor-? in the Induction of Monocytic Differentiation of Human Leukemic Cell Lines

Annals of the New York Academy of Sciences ◽

10.1111/j.1749-6632.1990.tb16136.x ◽

1990 ◽

Vol 593 (1 Transforming) ◽

pp. 334-337

Author(s):

FABRIZIO BENEDETTI ◽

LYDIA A. FALK ◽

LARRY R. ELLINGSWORTH ◽

FRANCIS W. RUSCETTI ◽

CONNIE R. FALTYNEK

Keyword(s):

Growth Factor ◽

Tumor Necrosis Factor ◽

Cell Lines ◽

Tumor Necrosis ◽

Transforming Growth Factor ◽

Leukemic Cell ◽

Monocytic Differentiation ◽

Human Leukemic Cell ◽

Leukemic Cell Lines ◽

Necrosis Factor

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Growth factor requirements of childhood acute leukemia: establishment of GM-CSF-dependent cell lines

Blood ◽

10.1182/blood.v70.1.192.bloodjournal701192 ◽

1987 ◽

Vol 70 (1) ◽

pp. 192-199 ◽

Cited By ~ 1

Author(s):

B Lange ◽

M Valtieri ◽

D Santoli ◽

D Caracciolo ◽

F Mavilio ◽

...

Keyword(s):

Growth Factor ◽

Acute Leukemia ◽

Cell Lines ◽

Leukemic Cell ◽

Media Analysis ◽

Leukemic Cells ◽

Gm Csf ◽

Leukemic Cell Lines ◽

Dependent Cell ◽

Childhood Acute Leukemia

Eight permanent cell lines were established from cells of 50 consecutive patients with childhood acute leukemia. Three cell lines required growth factor-containing conditioned media. Analysis using blocking antisera and recombinant granulocytic macrophage (GM) colony- stimulating factor (CSF) identified GM-CSF as a growth factor required to establish the latter three cell lines and necessary for their continuous proliferation in chemically defined medium. Two of the GM- CSF-dependent cell lines were derived from patients with undifferentiated T- and a biphenotypic B-myelomonocytic leukemia, which suggests that GM-CSF might maintain proliferation of leukemias originating from immature progenitor cells. Cytogenetic analysis indicated that all established leukemic cell lines were aneuploid, with six lines containing chromosomal alterations related to those observed in the leukemic cells of the patient. Two patients did not have an abnormal clone identified in the marrow but did yield an aneuploid cell line. These studies indicate that GM-CSF-dependent leukemic cell lines can be established in a fraction of childhood leukemia. These cell lines lend themselves to studies aimed at the evaluation in vitro of the role of growth factors in controlling proliferation and differentiation of leukemic cells.

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