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1.
Cancer Cell ; 35(4): 649-663.e10, 2019 04 15.
Article in English | MEDLINE | ID: mdl-30991025

ABSTRACT

The BCR-ABL1 fusion protein is the cause of chronic myeloid leukemia (CML) and of a significant fraction of adult-onset B cell acute lymphoblastic leukemia (B-ALL) cases. Using mouse models and patient-derived samples, we identified an essential role for γ-catenin in the initiation and maintenance of BCR-ABL1+ B-ALL but not CML. The selectivity was explained by a partial γ-catenin dependence of MYC expression together with the susceptibility of B-ALL, but not CML, to reduced MYC levels. MYC and γ-catenin enabled B-ALL maintenance by augmenting BIRC5 and enforced BIRC5 expression overcame γ-catenin loss. Since γ-catenin was dispensable for normal hematopoiesis, these lineage- and disease-specific features of canonical Wnt signaling identified a potential therapeutic target for the treatment of BCR-ABL1+ B-ALL.


Subject(s)
Fusion Proteins, bcr-abl/metabolism , Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Wnt Signaling Pathway , gamma Catenin/metabolism , Animals , Fusion Proteins, bcr-abl/genetics , Gene Expression Regulation, Leukemic , Humans , K562 Cells , Mice, Inbred NOD , Mice, SCID , Mice, Transgenic , Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/genetics , Precursor B-Cell Lymphoblastic Leukemia-Lymphoma/pathology , Proto-Oncogene Proteins c-myc/genetics , Proto-Oncogene Proteins c-myc/metabolism , Survivin/genetics , Survivin/metabolism , beta Catenin/genetics , beta Catenin/metabolism , gamma Catenin/genetics
2.
Mol Cell Biol ; 32(22): 4523-33, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22949508

ABSTRACT

The ability to generate appropriate defense responses is crucial for the survival of an organism exposed to pathogenesis-inducing insults. However, the mechanisms that allow tissues and organs to cope with such stresses are poorly understood. Here we show that caspase-3-knockout mice or caspase inhibitor-treated mice were defective in activating the antiapoptotic Akt kinase in response to various chemical and environmental stresses causing sunburns, cardiomyopathy, or colitis. Defective Akt activation in caspase-3-knockout mice was accompanied by increased cell death and impaired survival in some cases. Mice homozygous for a mutation in RasGAP that prevents its cleavage by caspase-3 exhibited a similar defect in Akt activation, leading to increased apoptosis in stressed organs, marked deterioration of their physiological functions, and stronger disease development. Our results provide evidence for the relevance of caspase-3 as a stress intensity sensor that controls cell fate by either initiating a RasGAP cleavage-dependent cell resistance program or a cell suicide response.


Subject(s)
Cardiomyopathies/enzymology , Caspase 3/genetics , Colitis/enzymology , Proto-Oncogene Proteins c-akt/metabolism , Sunburn/enzymology , p120 GTPase Activating Protein/genetics , Animals , Base Sequence , Cardiomyopathies/chemically induced , Cardiomyopathies/genetics , Caspase 3/deficiency , Cell Death/drug effects , Cell Death/radiation effects , Colitis/chemically induced , Colitis/genetics , Dextran Sulfate , Doxorubicin , Enzyme Activation/drug effects , Enzyme Inhibitors/pharmacology , Gene Expression Regulation/drug effects , Gene Expression Regulation/radiation effects , Hemodynamics , Mice , Mice, Knockout , Molecular Sequence Data , Mutation , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Proto-Oncogene Proteins c-akt/genetics , Signal Transduction/drug effects , Signal Transduction/genetics , Signal Transduction/radiation effects , Stress, Physiological , Sunburn/genetics , Ultraviolet Rays , p120 GTPase Activating Protein/antagonists & inhibitors , p120 GTPase Activating Protein/deficiency
3.
PLoS One ; 6(11): e27639, 2011.
Article in English | MEDLINE | ID: mdl-22132120

ABSTRACT

BACKGROUND: Natural Killer (NK) cells are thought to protect from residual leukemic cells in patients receiving stem cell transplantation. However, multiple retrospective analyses of patient data have yielded conflicting conclusions regarding a putative role of NK cells and the essential NK cell recognition events mediating a protective effect against leukemia. Further, a NK cell mediated protective effect against primary leukemia in vivo has not been shown directly. METHODOLOGY/PRINCIPAL FINDINGS: Here we addressed whether NK cells have the potential to control chronic myeloid leukemia (CML) arising based on the transplantation of BCR-ABL1 oncogene expressing primary bone marrow precursor cells into lethally irradiated recipient mice. These analyses identified missing-self recognition as the only NK cell-mediated recognition strategy, which is able to significantly protect from the development of CML disease in vivo. CONCLUSION: Our data provide a proof of principle that NK cells can control primary leukemic cells in vivo. Since the presence of NK cells reduced the abundance of leukemia propagating cancer stem cells, the data raise the possibility that NK cell recognition has the potential to cure CML, which may be difficult using small molecule BCR-ABL1 inhibitors. Finally, our findings validate approaches to treat leukemia using antibody-based blockade of self-specific inhibitory MHC class I receptors.


Subject(s)
Killer Cells, Natural/immunology , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/immunology , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/prevention & control , Self Tolerance/immunology , Animals , Cell Proliferation , Humans , Major Histocompatibility Complex/immunology , Mice , Mice, Inbred C57BL , Models, Immunological , Myeloid Cells/immunology , Myeloid Cells/pathology , Neoplastic Stem Cells/immunology , Neoplastic Stem Cells/pathology
4.
Proc Natl Acad Sci U S A ; 107(21): 9777-82, 2010 May 25.
Article in English | MEDLINE | ID: mdl-20457902

ABSTRACT

Immune protection from intracellular pathogens depends on the generation of terminally differentiated effector and of multipotent memory precursor CD8 T cells, which rapidly regenerate effector and memory cells during recurrent infection. The identification of factors and pathways involved in CD8 T cell differentiation is of obvious importance to improve vaccination strategies. Here, we show that mice lacking T cell factor 1 (Tcf-1), a nuclear effector of the canonical Wingless/Integration 1 (Wnt) signaling pathway, mount normal effector and effector memory CD8 T cell responses to infection with lymphocytic choriomeningitis virus (LCMV). However, Tcf-1-deficient CD8 T cells are selectively impaired in their ability to expand upon secondary challenge and to protect from recurrent virus infection. Tcf-1-deficient mice essentially lack CD8 memory precursor T cells, which is evident already at the peak of the primary response, suggesting that Tcf-1 programs CD8 memory cell fate. The function of Tcf-1 to establish CD8 T cell memory is dependent on the catenin-binding domain in Tcf-1 and requires the Tcf-1 coactivators and Wnt signaling intermediates beta-catenin and gamma-catenin. These findings demonstrate that the canonical Wnt signaling pathway plays an essential role for CD8 central memory T cell differentiation under physiological conditions in vivo. They raise the possibility that modulation of Wnt signaling may be exploited to improve the generation of CD8 memory T cells during vaccination or for therapies designed to promote sustained cytotoxic CD8 T cell responses against tumors.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , Immunologic Memory , Signal Transduction , T Cell Transcription Factor 1/immunology , Animals , CD8-Positive T-Lymphocytes/cytology , CD8-Positive T-Lymphocytes/metabolism , Cell Proliferation , Hepatocyte Nuclear Factor 1-alpha , Lymphocytic choriomeningitis virus/immunology , Mice , Mice, Inbred C57BL , Protein Binding , T Cell Transcription Factor 1/deficiency , Wnt Proteins/metabolism , beta Catenin/immunology , beta Catenin/metabolism , gamma Catenin/immunology , gamma Catenin/metabolism
5.
Blood ; 111(1): 142-9, 2008 Jan 01.
Article in English | MEDLINE | ID: mdl-17906078

ABSTRACT

The canonical Wnt signaling pathway plays key roles in stem-cell maintenance, progenitor cell expansion, and lineage decisions. Transcriptional responses induced by Wnt depend on the association of either beta-catenin or gamma-catenin with lymphoid enhancer factor/T cell factor transcription factors. Here we show that hematopoiesis, including thymopoiesis, is normal in the combined absence of beta- and gamma-catenin. Double-deficient hematopoietic stem cells maintain long-term repopulation capacity and multilineage differentiation potential. Unexpectedly, 2 independent ex vivo reporter gene assays show that Wnt signal transmission is maintained in double-deficient hematopoietic stem cells, thymocytes, or peripheral T cells. In contrast, Wnt signaling is strongly reduced in thymocytes lacking TCF-1 or in nonhematopoietic cells devoid of beta-catenin. These data provide the first evidence that hematopoietic cells can transduce canonical Wnt signals in the combined absence of beta- and gamma-catenin.


Subject(s)
Cell Lineage/physiology , Hematopoiesis/physiology , Thymus Gland/cytology , beta Catenin/genetics , gamma Catenin/genetics , Animals , Bone Marrow Cells/cytology , Bone Marrow Cells/metabolism , Hematopoietic Stem Cells/cytology , Hematopoietic Stem Cells/metabolism , Hybridomas , Mice , Mice, Inbred C57BL , Mice, Transgenic , Signal Transduction/physiology , Spleen/cytology , T-Lymphocytes/cytology , T-Lymphocytes/metabolism , Wnt Proteins/metabolism , beta Catenin/metabolism , gamma Catenin/metabolism
6.
J Bacteriol ; 189(21): 7643-52, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17766416

ABSTRACT

In this report, we investigate the link between nutrient limitation, RelA-mediated (p)ppGpp production, and virulence in the phytopathogen Erwinia carotovora subsp. atroseptica. A relA null mutant (JWC7) was constructed by allelic exchange, and we confirmed that, unlike the wild-type progenitor, this mutant did not produce elevated levels of (p)ppGpp upon nutrient downshift. However, (p)ppGpp production could be restored in strain JWC7 during nutrient limitation by supplying relA in trans. During growth on exoenzyme-inducing minimal medium, the relA mutant showed a diminution in secreted pectate lyase and protease activities and a severe defect in motility. The relA mutant was also impaired in its ability to cause rot in potato tubers. In the presence of serine hydroxamate (a competitive inhibitor of seryl tRNA synthase and a potent inducer of the stringent response in wild-type E. carotovora subsp. atroseptica), exoenzyme production was essentially abolished in JWC7 but could be restored in the presence of plasmid-borne relA. The inhibition of exoenzyme production in JWC7 caused by serine hydroxamate could not be overcome by addition of the quorum-sensing signal molecule, N-3-oxohexanoyl-l-homoserine lactone. Quantitative reverse transcription-PCR analysis of selected RNA species confirmed that the effects of relA on secreted pectate lyase activity and motility could be attributed to a reduction in transcription of the corresponding genes. We conclude that nutrient limitation is a potent environmental cue that triggers (p)ppGpp-dependent exoenzyme production in E. carotovora subsp. atroseptica. Furthermore, our data suggest that nutrient limitation [or rather, (p)ppGpp accumulation] is a prerequisite for effective quorum-sensing-dependent activation of exoenzyme production.


Subject(s)
Coenzymes/biosynthesis , Guanosine Tetraphosphate/metabolism , Ligases/metabolism , Pectobacterium carotovorum/enzymology , Bacterial Proteins/metabolism , Culture Media , DNA Primers , Genotype , Guanosine Tetraphosphate/biosynthesis , Kinetics , Ligases/deficiency , Ligases/genetics , Pectobacterium carotovorum/genetics , Pectobacterium carotovorum/growth & development , Polymerase Chain Reaction
7.
Science ; 315(5809): 230-3, 2007 Jan 12.
Article in English | MEDLINE | ID: mdl-17218525

ABSTRACT

alphabeta and gammadelta T cells originate from a common, multipotential precursor population in the thymus, but the molecular mechanisms regulating this lineage-fate decision are unknown. We have identified Sox13 as a gammadelta-specific gene in the immune system. Using Sox13 transgenic mice, we showed that this transcription factor promotes gammadelta T cell development while opposing alphabeta T cell differentiation. Conversely, mice deficient in Sox13 expression exhibited impaired development of gammadelta T cells but not alphabeta T cells. One mechanism of SOX13 function is the inhibition of signaling by the developmentally important Wnt/T cell factor (TCF) pathway. Our data thus reveal a dominant pathway regulating the developmental fate of these two lineages of T lymphocytes.


Subject(s)
Autoantigens/metabolism , High Mobility Group Proteins/metabolism , Lymphopoiesis , Receptors, Antigen, T-Cell, alpha-beta/analysis , Receptors, Antigen, T-Cell, gamma-delta/analysis , T-Lymphocyte Subsets/cytology , Animals , Autoantigens/genetics , CD4 Antigens/genetics , Cell Line , Cell Lineage , Cell Proliferation , Embryonic Development , Gene Expression Profiling , Gene Expression Regulation , Gene Rearrangement, T-Lymphocyte , High Mobility Group Proteins/genetics , Humans , Mice , Mice, Transgenic , Receptors, Antigen, T-Cell, gamma-delta/genetics , Signal Transduction , T Cell Transcription Factor 1/physiology , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism , Wnt Proteins/metabolism
8.
Sci Prog ; 89(Pt 3-4): 167-211, 2006.
Article in English | MEDLINE | ID: mdl-17338438

ABSTRACT

Many Gram-negative bacteria employ a mechanism of cell-cell communication known as quorum sensing (QS). The role of QS is to enable the cells in a culture to coordinate their gene expression profile with changes in the population cell density. The best characterized mechanisms of QS employ N-acylated homoserine lactones (AHLs) as signalling molecules. These AHLs are made by enzymes known as LuxI homologs, and accumulate in the culture supernatant at a rate proportional to the increase in cell density. Once the AHL concentration exceeds a certain threshold value, these ligands bind to intracellular receptors known as LuxR homologs. The latter are transcriptional regulators, whose activity alters upon binding the AHL ligand, thereby eliciting a change in gene transcription. Over the last five years, it has become increasingly obvious that this is a rather simplistic view of AHL-dependent QS, and that in fact, there is considerable diversity in the way in which LuxI-R homologs operate. The aim of the current review is to describe these variations on the basic theme, and to show how functional genomics is revolutionizing our understanding of QS-controlled regulons.


Subject(s)
4-Butyrolactone/analogs & derivatives , Bacterial Proteins/metabolism , Biofilms , Gene Expression Regulation, Bacterial , Gram-Negative Bacteria/physiology , Models, Biological , Quorum Sensing/physiology , Transcription Factors/metabolism , 4-Butyrolactone/metabolism , Population Density
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