ABSTRACT
T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy with few available targeted therapies. We previously reported that the phosphatase calcineurin (Cn) is required for LIC (leukemia Initiating Capacity) potential of T-ALL pointing to Cn as an interesting therapeutic target. Calcineurin inhibitors have however unwanted side effect. NFAT transcription factors play crucial roles downstream of calcineurin during thymocyte development, T cell differentiation, activation and anergy. Here we elucidate NFAT functional relevance in T-ALL. Using murine T-ALL models in which Nfat genes can be inactivated either singly or in combination, we show that NFATs are required for T-ALL LIC potential and essential to survival, proliferation and migration of T-ALL cells. We also demonstrate that Nfat genes are functionally redundant in T-ALL and identified a node of genes commonly deregulated upon Cn or NFAT inactivation, which may serve as future candidate targets for T-ALL.
Subject(s)
NFATC Transcription Factors/metabolism , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/metabolism , T-Lymphocytes/metabolism , Animals , Calcineurin/metabolism , Calcineurin Inhibitors/pharmacology , Cell Movement/drug effects , Cell Movement/physiology , Cell Proliferation/drug effects , Cell Proliferation/physiology , Cell Survival/drug effects , Cell Survival/physiology , Cells, Cultured , Lymphocyte Activation/drug effects , Lymphocyte Activation/physiology , Mice , Mice, Inbred C57BL , NIH 3T3 Cells , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Signal Transduction/drug effects , Signal Transduction/physiology , T-Lymphocytes/drug effectsABSTRACT
Impaired cell migration has been demonstrated in T cell acute lymphoblastic leukemia (T-ALL) cells upon calcineurin inactivation, among other phenotypic traits including increased apoptosis, inhibition of cell proliferation, and ultimately inhibition of leukemia-initiating cell (LIC) activity. Herein we demonstrate that the chemokine receptor CXCR4 is essential to the LIC activity of T-ALL leukemic cells both in NOTCH-induced mouse T-ALL and human T-ALL xenograft models. We further demonstrate that calcineurin regulates CXCR4 cell-surface expression in a cortactin-dependent manner, a mechanism essential to the migratory properties of T-ALL cells. Because 20%-25% of pediatric and over 50% of adult patients with T-ALL do not achieve complete remission and relapse, our results call for clinical trials incorporating CXCR4 antagonists in T-ALL treatment.
Subject(s)
Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/pathology , Receptors, CXCR4/metabolism , Animals , Apoptosis/physiology , Calcineurin/metabolism , Cell Movement/physiology , Cell Proliferation/physiology , Heterografts , Humans , Mice , Mice, Inbred NOD , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/genetics , Receptor, Notch1/genetics , Receptor, Notch1/metabolism , Receptors, CXCR4/biosynthesis , Receptors, CXCR4/genetics , Signal TransductionABSTRACT
Methamphetamine (METH) is a highly addictive psychostimulant drug of abuse that negatively interferes with neurogenesis. In fact, we have previously shown that METH triggers stem/progenitor cell death and decreases neuronal differentiation in the dentate gyrus (DG). Still, little is known regarding its effect on DG stem cell properties. Herein, we investigate the impact of METH on mice DG stem/progenitor cell self-renewal functions. METH (10nM) decreased DG stem cell self-renewal, while 1nM delayed cell cycle in the G0/G1-to-S phase transition and increased the number of quiescent cells (G0 phase), which correlated with a decrease in cyclin E, pEGFR and pERK1/2 protein levels. Importantly, both drug concentrations (1 or 10nM) did not induce cell death. In accordance with the impairment of self-renewal capacity, METH (10nM) decreased Sox2(+)/Sox2(+) while increased Sox2(-)/Sox2(-) pairs of daughter cells. This effect relied on N-methyl-d-aspartate (NMDA) signaling, which was prevented by the NMDA receptor antagonist, MK-801 (10µM). Moreover, METH (10nM) increased doublecortin (DCX) protein levels consistent with neuronal differentiation. In conclusion, METH alters DG stem cell properties by delaying cell cycle and decreasing self-renewal capacities, mechanisms that may contribute to DG neurogenesis impairment followed by cognitive deficits verified in METH consumers.
Subject(s)
Cell Proliferation/drug effects , Central Nervous System Stimulants/toxicity , Dentate Gyrus/drug effects , Methamphetamine/toxicity , Neural Stem Cells/drug effects , Neurogenesis/drug effects , Neurons/drug effects , Animals , Animals, Newborn , Cell Cycle Checkpoints/drug effects , Cell Death/drug effects , Cells, Cultured , Cyclin E/metabolism , Dentate Gyrus/metabolism , Dentate Gyrus/pathology , Doublecortin Domain Proteins , Doublecortin Protein , ErbB Receptors/metabolism , Excitatory Amino Acid Antagonists/pharmacology , Mice, Inbred C57BL , Microtubule-Associated Proteins/metabolism , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , N-Methylaspartate/metabolism , Neural Stem Cells/metabolism , Neural Stem Cells/pathology , Neurons/metabolism , Neurons/pathology , Neuropeptides/metabolism , Phosphorylation , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Receptors, N-Methyl-D-Aspartate/metabolism , SOXB1 Transcription Factors/genetics , SOXB1 Transcription Factors/metabolism , Signal Transduction/drug effects , Time FactorsABSTRACT
Little is known about the mechanisms of mitotic spindle orientation during mammary gland morphogenesis. Here, we report the presence of huntingtin, the protein mutated in Huntington's disease, in mouse mammary basal and luminal cells throughout mammogenesis. Keratin 5-driven depletion of huntingtin results in a decreased pool and specification of basal and luminal progenitors, and altered mammary morphogenesis. Analysis of mitosis in huntingtin-depleted basal progenitors reveals mitotic spindle misorientation. In mammary cell culture, huntingtin regulates spindle orientation in a dynein-dependent manner. Huntingtin is targeted to spindle poles through its interaction with dynein and promotes the accumulation of NUMA and LGN. Huntingtin is also essential for the cortical localization of dynein, dynactin, NUMA, and LGN by regulating their kinesin 1-dependent trafficking along astral microtubules. We thus suggest that huntingtin is a component of the pathway regulating the orientation of mammary stem cell division, with potential implications for their self-renewal and differentiation properties.
Subject(s)
Cell Differentiation/genetics , Cell Division/genetics , Mammary Glands, Animal/cytology , Nerve Tissue Proteins/genetics , Nuclear Proteins/genetics , Stem Cells/cytology , Stem Cells/metabolism , Animals , Carrier Proteins/metabolism , Cell Cycle Proteins , Cell Line , Dynactin Complex , Dyneins/metabolism , Epithelium/metabolism , Female , Humans , Huntingtin Protein , Lactation/genetics , Mammary Glands, Animal/growth & development , Membrane Proteins/metabolism , Mice , Microtubule-Associated Proteins/metabolism , Mitosis , Morphogenesis , Multiprotein Complexes/metabolism , Nerve Tissue Proteins/metabolism , Nuclear Proteins/metabolism , Pregnancy , Protein Binding , Protein Transport , RNA Interference , Spindle ApparatusABSTRACT
Near full-length genomes of 4 unclassified HIV-1 variants infecting patients enrolled in an antenatal cohort in Canada were obtained by sequencing. All 4 variants showed original recombination profiles, including A1/A2/J, A1/D, and A1/G/J/CRF11_cpx structures. Identification of these variants highlights the growing prevalence of unique recombinant forms of HIV-1 in North America.
