Myeloid cell leukaemia 1 has a vital role in retinoic acid-mediated protection of Toll-like receptor 9-stimulated B cells from spontaneous and DNA damage-induced apoptosis

Background:Aberrant expression of eukaryotic translation initiation factor 4E (eIF4E) is common in many types of cancer including acute myeloid leukaemia (AML). Phosphorylation of eIF4E by MAPK-interacting kinases (Mnks) is essential for the eIF4E-mediated oncogenic activity. As such, the pharmacological inhibition of Mnks can be an effective strategy for the treatment of cancer.Methods:A series of N-phenyl-4-(1H-pyrrol-3-yl)pyrimidin-2-amine derivatives was designed and synthesised. The Mnk inhibitory activity of these derivatives as well as their anti-proliferative activity against MV4-11 AML cells was determined.Results:These compounds were identified as potent Mnk2 inhibitors. Most of them demonstrated potent anti-proliferative activity against MV4-11 AML cells. The cellular mechanistic studies of the representative inhibitors revealed that they reduced the level of phosphorylated eIF4E and induced apoptosis by down-regulating the anti-apoptotic protein myeloid cell leukaemia 1 (Mcl-1) and by cleaving poly(ADP-ribose)polymerase (PARP). The lead compound 7k possessed desirable pharmacokinetic properties and oral bioavailability.Conclusion:This work proposes that exploration of the structural diversity in the context of Nphenyl- 4-(1H-pyrrol-3-yl)pyrimidin-2-amine would offer potent and selective Mnk inhibitors.

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microRNA-29b contributes to pre-eclampsia through its effects on apoptosis, invasion and angiogenesis of trophoblast cells

Clinical Science ◽

10.1042/cs20120121 ◽

2012 ◽

Vol 124 (1) ◽

pp. 27-40 ◽

Cited By ~ 87

Author(s):

Pengfei Li ◽

Wei Guo ◽

Leilei Du ◽

Junli Zhao ◽

Yaping Wang ◽

...

Keyword(s):

Target Genes ◽

Inverse Correlation ◽

Myeloid Cell ◽

Trophoblast Cell ◽

Trophoblast Invasion ◽

Cell Leukaemia ◽

Trophoblast Cells ◽

Computer Based ◽

Induced Apoptosis ◽

Endothelial Growth Factor

PE (pre-eclampsia), a pregnancy-specific disorder, is characterized by increased trophoblast cell death and deficient trophoblast invasion and reduced trophoblast-mediated remodelling of spiral arteries. The present study was performed to determine the function of miR-29b (microRNA-29b) in trophoblast cells and its underlying role in the pathogenesis of PE. The prediction of miR-29b target genes was performed using computer-based programs, including Targetscan, Pictar and miRBase. The function of these target genes was analysed further by gene ontology (GO). The effects of miR-29b on apoptosis, and invasion and angiogenesis of trophoblast cell lines (HTR-8/SVneo, BeWo and JAR) were examined by flow cytometry and Matrigel assay respectively. We found that miR-29b induced apoptosis and inhibited invasion and angiogenesis of trophoblast cells. Further studies confirmed that miR-29b regulated the expression of MCL1 (myeloid cell leukaemia sequence 1), MMP2 (encoding matrix metallproteinase 2), VEGFA (vascular endothelial growth factor A) and ITGB1 (integrin β1) genes by directly binding to their 3′-UTRs (untranslated regions). Moreover, we identified that there was an inverse correlation between miR-29b and its target genes in subjects with PE. Taken together, these findings support a novel role for miR-29b in invasion, apoptosis and angiogenesis of trophoblast cells, and miR-29b may become a new potential therapeutic target for PE.

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The Chimeric E2A-HLF Transcription Factor Abrogates p53-Induced Apoptosis in Myeloid Leukemia Cells

Blood ◽

10.1182/blood.v92.4.1397.416k19_1397_1405 ◽

1998 ◽

Vol 92 (4) ◽

pp. 1397-1405

Author(s):

Rachel A. Altura ◽

Takeshi Inukai ◽

Richard A. Ashmun ◽

Gerard P. Zambetti ◽

Martine F. Roussel ◽

...

Keyword(s):

Dna Damage ◽

Cell Death ◽

B Cells ◽

Growth Factor ◽

Myeloid Leukemia ◽

Leukemic Cells ◽

Leukemia Cells ◽

Wild Type ◽

Wild Type P53 ◽

Induced Apoptosis

Leukemic lymphoblasts expressing the E2A-HLF oncoprotein possess wild-type p53 genes, but do not undergo apoptosis in response to DNA damage. Experimentally, E2A-HLF prevents apoptosis due to growth factor deprivation or γ-irradiation in interleukin-3 (IL-3)–dependent murine pro-B cells. To directly test the chimeric protein’s ability to abrogate p53-mediated cell death, we used mouse myeloid leukemia cells (M1p53tsval) that constitutively express a temperature-sensitive (ts) mutant p53 gene and undergo apoptosis when p53 assumes an active wild-type configuration. This effect is blocked by treatment with IL-6, which allows the cells to survive in culture despite wild-type p53 activation. We introduced E2A-HLF into M1p53tsval cells and found that they were resistant to p53-mediated apoptosis and that E2A-HLF effectively substituted for the survival functions of IL-6. The expression of p53-responsive genes such as p21 and Bax was upregulated normally, suggesting that E2A-HLF acts downstream of p53 to block execution of the p53-induced apoptotic program. NFIL3, a growth factor-regulated bZIP protein that binds to the same DNA-consensus site as E2A-HLF, delays apoptosis in IL-3–dependent pro-B cells deprived of growth factor. By contrast, in the present study, enforced expression of NFIL3 failed to protect M1p53tsval cells from p53-dependent apoptosis and actively antagonized the ability of IL-6 to rescue cells from that fate, consistent with its role as either a transcriptional repressor or activator, depending on the cell type in which it is expressed. We conclude that the E2A-HLF chimera abrogates p53-induced apoptosis in leukemic cells, possibly through the transcriptional modulation of cell death pathways that are activated by p53 in response to DNA damage. © 1998 by The American Society of Hematology.

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The Chimeric E2A-HLF Transcription Factor Abrogates p53-Induced Apoptosis in Myeloid Leukemia Cells

Blood ◽

10.1182/blood.v92.4.1397 ◽

1998 ◽

Vol 92 (4) ◽

pp. 1397-1405 ◽

Cited By ~ 19

Author(s):

Rachel A. Altura ◽

Takeshi Inukai ◽

Richard A. Ashmun ◽

Gerard P. Zambetti ◽

Martine F. Roussel ◽

...

Keyword(s):

Dna Damage ◽

Cell Death ◽

B Cells ◽

Growth Factor ◽

Myeloid Leukemia ◽

Leukemic Cells ◽

Leukemia Cells ◽

Wild Type ◽

Wild Type P53 ◽

Induced Apoptosis

Abstract Leukemic lymphoblasts expressing the E2A-HLF oncoprotein possess wild-type p53 genes, but do not undergo apoptosis in response to DNA damage. Experimentally, E2A-HLF prevents apoptosis due to growth factor deprivation or γ-irradiation in interleukin-3 (IL-3)–dependent murine pro-B cells. To directly test the chimeric protein’s ability to abrogate p53-mediated cell death, we used mouse myeloid leukemia cells (M1p53tsval) that constitutively express a temperature-sensitive (ts) mutant p53 gene and undergo apoptosis when p53 assumes an active wild-type configuration. This effect is blocked by treatment with IL-6, which allows the cells to survive in culture despite wild-type p53 activation. We introduced E2A-HLF into M1p53tsval cells and found that they were resistant to p53-mediated apoptosis and that E2A-HLF effectively substituted for the survival functions of IL-6. The expression of p53-responsive genes such as p21 and Bax was upregulated normally, suggesting that E2A-HLF acts downstream of p53 to block execution of the p53-induced apoptotic program. NFIL3, a growth factor-regulated bZIP protein that binds to the same DNA-consensus site as E2A-HLF, delays apoptosis in IL-3–dependent pro-B cells deprived of growth factor. By contrast, in the present study, enforced expression of NFIL3 failed to protect M1p53tsval cells from p53-dependent apoptosis and actively antagonized the ability of IL-6 to rescue cells from that fate, consistent with its role as either a transcriptional repressor or activator, depending on the cell type in which it is expressed. We conclude that the E2A-HLF chimera abrogates p53-induced apoptosis in leukemic cells, possibly through the transcriptional modulation of cell death pathways that are activated by p53 in response to DNA damage. © 1998 by The American Society of Hematology.

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STAT3-mediated transcription of Bcl-2, Mcl-1 and c-IAP2 prevents apoptosis in polyamine-depleted cells

Biochemical Journal ◽

10.1042/bj20050465 ◽

2005 ◽

Vol 392 (2) ◽

pp. 335-344 ◽

Cited By ~ 156

Author(s):

Sujoy Bhattacharya ◽

Ramesh M. Ray ◽

Leonard R. Johnson

Keyword(s):

Myeloid Cell ◽

Dominant Negative ◽

Cell Leukaemia ◽

Cell Periphery ◽

Inhibitory Peptide ◽

Protein Levels ◽

Tnf Α ◽

Apoptosis Protein ◽

Before And After ◽

Induced Apoptosis

Activation of STAT3 (signal transducer and activator of transcription 3) plays a crucial role in cell survival and proliferation. The aim of the present study was to clarify the role of STAT3 signalling in the protection of polyamine-depleted intestinal epithelial cells against TNF-α (tumour necrosis factor-α)-induced apoptosis. Polyamine depletion by DFMO (α-difluoromethylornithine) caused phosphorylation of STAT3 at Tyr-705 and Ser-727. Phospho-Tyr-705 STAT3 was immunolocalized at the cell periphery and nucleus, whereas phospho-Ser-727 STAT3 was predominantly detected in the nucleus of polyamine-depleted cells. Sustained phosphorylation of STAT3 at tyrosine residues was observed in polyamine-depleted cells after exposure to TNF-α. Inhibition of STAT3 activation by AG490 or cell-membrane-permeant inhibitory peptide (PpYLKTK; where pY represents phospho-Tyr) increased the sensitivity of polyamine-depleted cells to apoptosis. Expression of DN-STAT3 (dominant negative-STAT3) completely eliminated the protective effect of DFMO against TNF-α-induced apoptosis. Polyamine depletion increased mRNA and protein levels for Bcl-2, Mcl-1 (myeloid cell leukaemia-1) and c-IAP2 (inhibitor of apoptosis protein-2). Significantly higher levels of Bcl-2 and c-IAP2 proteins were observed in polyamine-depleted cells before and after 9 h of TNF-α treatment. Inhibition of STAT3 by AG490 and DN-STAT3 decreased Bcl-2 promoter activity. DN-STAT3 decreased mRNA and protein levels for Bcl-2, Mcl-1 and c-IAP2 in polyamine-depleted cells. siRNA (small interfering RNA)-mediated inhibition of Bcl-2, Mcl-1 and c-IAP2 protein levels increased TNF-α-induced apoptosis. DN-STAT3 induced the activation of caspase-3 and PARP [poly(ADP-ribose) polymerase] cleavage in polyamine-depleted cells. These results suggest that activation of STAT3 in response to polyamine depletion increases the transcription and subsequent expression of anti-apoptotic Bcl-2 and IAP family proteins and thereby promotes survival of cells against TNF-α-induced apoptosis.

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c-Myc Augments Gamma Irradiation-Induced Apoptosis by Suppressing Bcl-XL

Molecular and Cellular Biology ◽

10.1128/mcb.23.20.7256-7270.2003 ◽

2003 ◽

Vol 23 (20) ◽

pp. 7256-7270 ◽

Cited By ~ 88

Author(s):

Kirsteen H. Maclean ◽

Ulrich B. Keller ◽

Carlos Rodriguez-Galindo ◽

Jonas A. Nilsson ◽

John L. Cleveland

Keyword(s):

Dna Damage ◽

B Cells ◽

Gamma Irradiation ◽

P53 Mutations ◽

Apoptotic Response ◽

Cycle Arrest ◽

Mouse Embryo Fibroblasts ◽

Damage Response ◽

Induced Apoptosis

ABSTRACT Alterations in MYC and p53 are hallmarks of cancer. p53 coordinates the response to gamma irradiation (γ-IR) by either triggering apoptosis or cell cycle arrest. c-Myc activates the p53 apoptotic checkpoint, and thus tumors overexpressing MYC often harbor p53 mutations. Nonetheless, many of these cancers are responsive to therapy, suggesting that Myc may sensitize cells to γ-IR independent of p53. In mouse embryo fibroblasts (MEFs) and in Eμ-myc transgenic B cells in vivo, c-Myc acts in synergy with γ-IR to trigger apoptosis, but alone, when cultured in growth medium, it does not induce a DNA damage response. Surprisingly, c-Myc also sensitizes p53-deficient MEFs to γ-IR-induced apoptosis. In normal cells, and in precancerous B cells of Eμ-myc transgenic mice, this apoptotic response is associated with the suppression of the antiapoptotic regulators Bcl-2 and Bcl-XL and with the concomitant induction of Puma, a proapoptotic BH3-only protein. However, in p53-null MEFs only Bcl-XL expression was suppressed, suggesting levels of Bcl-XL regulate the response to γ-IR. Indeed, Bcl-XL overexpression blocked this apoptotic response, whereas bcl-X-deficient MEFs were inherently and selectively sensitive to γ-IR-induced apoptosis. Therefore, MYC may sensitize tumor cells to DNA damage by suppressing Bcl-X.

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BCL6 is critical for the development of a diverse primary B cell repertoire

Journal of Experimental Medicine ◽

10.1084/jem.20091299 ◽

2010 ◽

Vol 207 (6) ◽

pp. 1209-1221 ◽

Cited By ~ 82

Author(s):

Cihangir Duy ◽

J. Jessica Yu ◽

Rahul Nahar ◽

Srividya Swaminathan ◽

Soo-Mi Kweon ◽

...

Keyword(s):

Dna Damage ◽

B Cells ◽

B Cell ◽

Light Chain ◽

Gene Rearrangement ◽

Chain Gene ◽

Cell Repertoire ◽

Light Chain Gene ◽

B Cell Repertoire ◽

Induced Apoptosis

BCL6 protects germinal center (GC) B cells against DNA damage–induced apoptosis during somatic hypermutation and class-switch recombination. Although expression of BCL6 was not found in early IL-7–dependent B cell precursors, we report that IL-7Rα–Stat5 signaling negatively regulates BCL6. Upon productive VH-DJH gene rearrangement and expression of a μ heavy chain, however, activation of pre–B cell receptor signaling strongly induces BCL6 expression, whereas IL-7Rα–Stat5 signaling is attenuated. At the transition from IL-7–dependent to –independent stages of B cell development, BCL6 is activated, reaches expression levels resembling those in GC B cells, and protects pre–B cells from DNA damage–induced apoptosis during immunoglobulin (Ig) light chain gene recombination. In the absence of BCL6, DNA breaks during Ig light chain gene rearrangement lead to excessive up-regulation of Arf and p53. As a consequence, the pool of new bone marrow immature B cells is markedly reduced in size and clonal diversity. We conclude that negative regulation of Arf by BCL6 is required for pre–B cell self-renewal and the formation of a diverse polyclonal B cell repertoire.

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Human chronic lymphocytic leukemia B cells can escape DNA damage-induced apoptosis through the nonhomologous end-joining DNA repair pathway

Blood ◽

10.1182/blood-2004-07-2888 ◽

2005 ◽

Vol 105 (12) ◽

pp. 4776-4783 ◽

Cited By ~ 69

Author(s):

L. Deriano

Keyword(s):

Dna Damage ◽

Dna Repair ◽

B Cells ◽

Chronic Lymphocytic Leukemia ◽

Lymphocytic Leukemia ◽

Nonhomologous End Joining ◽

Repair Pathway ◽

End Joining ◽

Induced Apoptosis

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The Bcl-2 proteins Noxa and Bcl-xL co-ordinately regulate oxidative stress-induced apoptosis

Biochemical Journal ◽

10.1042/bj20112023 ◽

2012 ◽

Vol 444 (1) ◽

pp. 69-78 ◽

Cited By ~ 15

Author(s):

Colins O. Eno ◽

Guoping Zhao ◽

Kristen E. Olberding ◽

Chi Li

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Molecular Mechanisms ◽

Myeloid Cell ◽

Cell Leukaemia ◽

Dependent Manner ◽

Embryonic Fibroblasts ◽

H2o2 Treatment ◽

Apoptotic Activity ◽

Induced Apoptosis

Because the detailed molecular mechanisms by which oxidative stress induces apoptosis are not completely known, we investigated how the complex Bcl-2 protein network might regulate oxidative stress-induced apoptosis. Using MEFs (mouse embryonic fibroblasts), we found that the endogenous anti-apoptotic Bcl-2 protein Bcl-xL prevented apoptosis initiated by H2O2. The BH3 (Bcl-2 homology 3)-only Bcl-2 protein Noxa was required for H2O2-induced cell death and was the single BH3-only Bcl-2 protein whose pro-apoptotic activity was completely antagonized by endogenous Bcl-xL. Upon H2O2 treatment, Noxa mRNA displayed the greatest increase among BH3-only Bcl-2 proteins. Expression levels of the anti-apoptotic Bcl-2 protein Mcl-1 (myeloid cell leukaemia sequence 1), the primary binding target of Noxa, were reduced in H2O2-treated cells in a Noxa-dependent manner, and Mcl-1 overexpression was able to prevent H2O2-induced cell death in Bcl-xL-deficient MEF cells. Importantly, reduction of the expression of both Mcl-1 and Bcl-xL caused spontaneous cell death. These studies reveal a signalling pathway in which H2O2 activates Noxa, leading to a decrease in Mcl-1 and subsequent cell death in the absence of Bcl-xL expression. The results of the present study indicate that both anti- and pro-apoptotic Bcl-2 proteins co-operate to regulate oxidative stress-induced apoptosis.

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