RESUMEN
Juvenile myelomonocytic leukemia (JMML), a clonal hematologic malignancy, originates from mutated hematopoietic stem cells (HSCs). The mechanism sustaining the persistence of mutant stem cells, leading to leukemia development, remains elusive. In this study, we conducted comprehensive examination of gene expression profiles, transcriptional factor regulons, and cell compositions/interactions throughout various stages of tumor cell development in Ptpn11 mutation-associated JMML. Our analyses revealed that leukemia-initiating Ptpn11 E76K/+ mutant stem cells exhibited de novo activation of the myeloid transcriptional program and aberrant developmental trajectories. These mutant stem cells displayed significantly elevated expression of innate immunity-associated anti-microbial peptides and pro-inflammatory proteins, particularly S100a9 and S100a8 . Biological experiments confirmed that S100a9/S100a8 conferred a selective advantage to the leukemia-initiating cells through autocrine effects and facilitated immune evasion by recruiting and promoting immune suppressive myeloid-derived suppressor cells (MDSCs) in the microenvironment. Importantly, pharmacological inhibition of S100a9/S100a8 signaling effectively impeded leukemia development from Ptpn11 E76K/+ mutant stem cells. These findings collectively suggest that JMML tumor-initiating cells exploit evolutionarily conserved innate immune and inflammatory mechanisms to establish clonal dominance.
RESUMEN
Mutations that decrease or increase the activity of the tyrosine phosphatase, SHP2 (encoded by PTPN11), promotes developmental disorders and several malignancies by varying phosphatase activity. We uncovered that SHP2 is a distinct class of an epigenetic enzyme; upon phosphorylation by the kinase ACK1/TNK2, pSHP2 was escorted by androgen receptor (AR) to chromatin, erasing hitherto unidentified pY54-H3 (phosphorylation of histones H3 at Tyr54) epigenetic marks to trigger a transcriptional program of AR. Noonan Syndrome with Multiple Lentigines (NSML) patients, SHP2 knock-in mice, and ACK1 knockout mice presented dramatic increase in pY54-H3, leading to loss of AR transcriptome. In contrast, prostate tumors with high pSHP2 and pACK1 activity exhibited progressive downregulation of pY54-H3 levels and higher AR expression that correlated with disease severity. Overall, pSHP2/pY54-H3 signaling acts as a sentinel of AR homeostasis, explaining not only growth retardation, genital abnormalities and infertility among NSML patients, but also significant AR upregulation in prostate cancer patients.
Asunto(s)
Epigénesis Genética , Histonas , Homeostasis , Ratones Noqueados , Neoplasias de la Próstata , Proteína Tirosina Fosfatasa no Receptora Tipo 11 , Receptores Androgénicos , Animales , Humanos , Masculino , Ratones , Cromatina/metabolismo , Histonas/metabolismo , Síndrome de Noonan/genética , Síndrome de Noonan/metabolismo , Fosforilación , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Proteína Tirosina Fosfatasa no Receptora Tipo 11/metabolismo , Proteína Tirosina Fosfatasa no Receptora Tipo 11/genética , Receptores Androgénicos/metabolismo , Receptores Androgénicos/genética , Transducción de SeñalRESUMEN
Mitochondria use different substrates for energy production and intermediatory metabolism according to the availability of nutrients and oxygen levels. The role of mitochondrial metabolic flexibility for CD8+ T cell immune response is poorly understood. Here, we report that the deletion or pharmacological inhibition of protein tyrosine phosphatase, mitochondrial 1 (PTPMT1) significantly decreased CD8+ effector T cell development and clonal expansion. In addition, PTPMT1 deletion impaired stem-like CD8+ T cell maintenance and accelerated CD8+ T cell exhaustion/dysfunction, leading to aggravated tumor growth. Mechanistically, the loss of PTPMT1 critically altered mitochondrial fuel selection-the utilization of pyruvate, a major mitochondrial substrate derived from glucose-was inhibited, whereas fatty acid utilization was enhanced. Persistent mitochondrial substrate shift and metabolic inflexibility induced oxidative stress, DNA damage, and apoptosis in PTPMT1 knockout cells. Collectively, this study reveals an important role of PTPMT1 in facilitating mitochondrial utilization of carbohydrates and that mitochondrial flexibility in energy source selection is critical for CD8+ T cell antitumor immunity.
Asunto(s)
Mitocondrias , Fosfohidrolasa PTEN , Fosfohidrolasa PTEN/metabolismo , Mitocondrias/metabolismo , Apoptosis , Diferenciación Celular , Linfocitos T CD8-positivos/metabolismoRESUMEN
BACKGROUND: Cardiac pathological outcome of metabolic remodeling is difficult to model using cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CMs) due to low metabolic maturation. METHODS: hiPSC-CM spheres were treated with AMP-activated protein kinase (AMPK) activators and examined for hiPSC-CM maturation features, molecular changes and the response to pathological stimuli. RESULTS: Treatment of hiPSC-CMs with AMPK activators increased ATP content, mitochondrial membrane potential and content, mitochondrial DNA, mitochondrial function and fatty acid uptake, indicating increased metabolic maturation. Conversely, the knockdown of AMPK inhibited mitochondrial maturation of hiPSC-CMs. In addition, AMPK activator-treated hiPSC-CMs had improved structural development and functional features-including enhanced Ca2+ transient kinetics and increased contraction. Transcriptomic, proteomic and metabolomic profiling identified differential levels of expression of genes, proteins and metabolites associated with a molecular signature of mature cardiomyocytes in AMPK activator-treated hiPSC-CMs. In response to pathological stimuli, AMPK activator-treated hiPSC-CMs had increased glycolysis, and other pathological outcomes compared to untreated cells. CONCLUSION: AMPK activator-treated cardiac spheres could serve as a valuable model to gain novel insights into cardiac diseases.
Asunto(s)
Proteínas Quinasas Activadas por AMP , Células Madre Pluripotentes Inducidas , Humanos , Proteínas Quinasas Activadas por AMP/genética , Proteínas Quinasas Activadas por AMP/metabolismo , Células Cultivadas , Proteómica , Miocitos Cardíacos/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Diferenciación Celular/fisiologíaRESUMEN
While mitochondria in different tissues have distinct preferences for energy sources, they are flexible in utilizing competing substrates for metabolism according to physiological and nutritional circumstances. However, the regulatory mechanisms and significance of metabolic flexibility are not completely understood. Here, we report that the deletion of Ptpmt1, a mitochondria-based phosphatase, critically alters mitochondrial fuel selection - the utilization of pyruvate, a key mitochondrial substrate derived from glucose (the major simple carbohydrate), is inhibited, whereas the fatty acid utilization is enhanced. Ptpmt1 knockout does not impact the development of the skeletal muscle or heart. However, the metabolic inflexibility ultimately leads to muscular atrophy, heart failure, and sudden death. Mechanistic analyses reveal that the prolonged substrate shift from carbohydrates to lipids causes oxidative stress and mitochondrial destruction, which in turn results in marked accumulation of lipids and profound damage in the knockout muscle cells and cardiomyocytes. Interestingly, Ptpmt1 deletion from the liver or adipose tissue does not generate any local or systemic defects. These findings suggest that Ptpmt1 plays an important role in maintaining mitochondrial flexibility and that their balanced utilization of carbohydrates and lipids is essential for both the skeletal muscle and the heart despite the two tissues having different preferred energy sources.
Cells are powered by mitochondria, a group of organelles that produce chemical energy in the form of molecules called ATP. This energy is derived from the breakdown of carbohydrates, fats, and proteins. The number of mitochondria in a cell and the energy source they use to produce ATP varies depending on the type of cell. Mitochondria can also switch the molecules they use to produce energy when the cell is responding to stress or disease. The heart and the skeletal muscles which allow movement are two tissues that require large amounts of energy, but it remained unknown whether disrupting mitochondrial fuel selection affects how these tissues work. To answer these questions, Zheng, Li, Li et al. investigated the role of an enzyme found in mitochondria called Ptpmt1. Genetically deleting Ptpmt1 in the heart and skeletal muscle of mice showed that while the development of these organs was not affected, mitochondria in these cells switched from using carbohydrates to using fats as an energy source. Over time, this shift damaged both the mitochondria and the tissues, leading to muscle wasting, heart failure, and sudden death in the mice. This suggests that balanced use of carbohydrates and fats is essential for the muscles and heart. These findings imply that long-term use of medications that alter the fuel that mitochondria use may be detrimental to patients' health and could cause heart dysfunction. This may be important for future drug development, as well as informing decisions about medication taken in the clinic.
Asunto(s)
Insuficiencia Cardíaca , Animales , Ratones , Ácidos Grasos , Glucosa , Insuficiencia Cardíaca/genética , Ratones Noqueados , Mitocondrias , Atrofia MuscularRESUMEN
Amino acid-mediated metabolism is one of the key catabolic and anabolic processes involved in diverse cellular functions. However, the role of the semi-essential amino acid arginine in normal and malignant hematopoietic cell development is poorly understood. Here we report that a continuous supply of exogenous arginine is required for the maintenance/function of normal hematopoietic stem cells (HSCs). Surprisingly, knockout of Slc7a3 (CAT3), a major L-arginine transporter, does not affect HSCs in steady-state or under stress. Although Slc7a3 is highly expressed in naïve and activated CD8 T cells, neither T cell development nor activation/proliferation is impacted by Slc7a3 depletion. Furthermore, the Slc7a3 deletion does not attenuate leukemia development driven by Pten loss or the oncogenic Ptpn11E76K mutation. Arginine uptake assays reveal that L-arginine uptake is not disrupted in Slc7a3 knockout cells. These data suggest that extracellular arginine is critically important for HSCs, but CAT3 is dispensable for normal hematopoiesis and leukemogenesis.
Asunto(s)
Hematopoyesis , Animales , Ratones , Sistemas de Transporte de Aminoácidos Básicos/genética , Sistemas de Transporte de Aminoácidos Básicos/metabolismo , Arginina/metabolismo , Transporte Biológico , Hematopoyesis/genética , Células Madre Hematopoyéticas/metabolismo , Proteínas de Transporte de Membrana/metabolismoRESUMEN
Environmental stresses, including hypoxia or detachment for anchorage independence, or attenuation of mitochondrial respiration through inhibition of electron transport chain induce reductive carboxylation in cells with an enhanced fraction of citrate arising through reductive metabolism of glutamine. This metabolic process contributes to redox homeostasis and sustains biosynthesis of lipids. Reductive carboxylation is often dependent on cytosolic isocitrate dehydrogenase 1 (IDH1). However, whether diverse cellular signals induce reductive carboxylation differentially or through a common signaling converging node remains unclear. We found that induction of reductive carboxylation commonly requires enhanced tyrosine phosphorylation and activation of IDH1, which, surprisingly, is achieved by attenuation of a cytosolic protein tyrosine phosphatase, Src homology region 2 domain-containing phosphatase-2 (SHP-2). Mechanistically, diverse signals induce reductive carboxylation by converging at upregulation of NADPH oxidase 2, leading to elevated cytosolic reactive oxygen species that consequently inhibit SHP-2. Together, our work elucidates the signaling basis underlying reductive carboxylation in cancer cells.
Asunto(s)
Isocitrato Deshidrogenasa , Neoplasias , Línea Celular Tumoral , Ciclo del Ácido Cítrico , Glutamina/metabolismo , Isocitrato Deshidrogenasa/metabolismo , Oxidación-Reducción , Fosforilación , Proteína Tirosina Fosfatasa no Receptora Tipo 11/metabolismoRESUMEN
Development of normal blood cells is often suppressed in juvenile myelomonocytic leukemia (JMML), a myeloproliferative neoplasm (MPN) of childhood, causing complications and impacting therapeutic outcomes. However, the mechanism underlying this phenomenon remains uncharacterized. To address this question, we induced the most common mutation identified in JMML (Ptpn11E76K) specifically in the myeloid lineage with hematopoietic stem cells (HSCs) spared. These mice uniformly developed a JMML-like MPN. Importantly, HSCs in the same bone marrow (BM) microenvironment were aberrantly activated and differentiated at the expense of self-renewal. As a result, HSCs lost quiescence and became exhausted. A similar result was observed in wild-type (WT) donor HSCs when co-transplanted with Ptpn11E76K/+ BM cells into WT mice. Co-culture testing demonstrated that JMML/MPN cells robustly accelerated differentiation in mouse and human normal hematopoietic stem/progenitor cells. Cytokine profiling revealed that Ptpn11E76K/+ MPN cells produced excessive IL-1ß, but not IL-6, T NF-α, IFN-γ, IL-1α, or other inflammatory cytokines. Depletion of the IL-1ß receptor effectively restored HSC quiescence, normalized their pool size, and rescued them from exhaustion in Ptpn11E76K/+/IL-1R-/- double mutant mice. These findings suggest IL-1ß signaling as a potential therapeutic target for preserving normal hematopoietic development in JMML.
Asunto(s)
Células Madre Hematopoyéticas , Inflamación , Interleucina-1beta , Leucemia Mielomonocítica Juvenil , Animales , Médula Ósea/patología , Células Madre Hematopoyéticas/patología , Humanos , Interleucina-1beta/biosíntesis , Interleucina-1beta/metabolismo , Leucemia Mielomonocítica Juvenil/inmunología , Leucemia Mielomonocítica Juvenil/metabolismo , Leucemia Mielomonocítica Juvenil/patología , Ratones , Trastornos Mieloproliferativos/inmunología , Trastornos Mieloproliferativos/metabolismo , Trastornos Mieloproliferativos/patología , Receptores de Interleucina-1/deficiencia , Microambiente TumoralRESUMEN
Mitogen-activated protein kinases (MAPKs) are inactivated by dual-specificity phosphatases (DUSPs), the activities of which are tightly regulated during cell differentiation. Using knockdown screening and single-cell transcriptional analysis, we demonstrate that DUSP4 is the phosphatase that specifically inactivates p38 kinase to promote megakaryocyte (Mk) differentiation. Mechanistically, PRMT1-mediated methylation of DUSP4 triggers its ubiquitinylation by an E3 ligase HUWE1. Interestingly, the mechanistic axis of the DUSP4 degradation and p38 activation is also associated with a transcriptional signature of immune activation in Mk cells. In the context of thrombocytopenia observed in myelodysplastic syndrome (MDS), we demonstrate that high levels of p38 MAPK and PRMT1 are associated with low platelet counts and adverse prognosis, while pharmacological inhibition of p38 MAPK or PRMT1 stimulates megakaryopoiesis. These findings provide mechanistic insights into the role of the PRMT1-DUSP4-p38 axis on Mk differentiation and present a strategy for treatment of thrombocytopenia associated with MDS.
Asunto(s)
Diferenciación Celular , Fosfatasas de Especificidad Dual , Megacariocitos , Fosfatasas de la Proteína Quinasa Activada por Mitógenos , Adulto , Animales , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Arginina/metabolismo , Línea Celular , Fosfatasas de Especificidad Dual/metabolismo , Estabilidad de Enzimas , Células HEK293 , Sistema de Señalización de MAP Quinasas , Megacariocitos/citología , Megacariocitos/enzimología , Metilación , Ratones Endogámicos C57BL , Fosfatasas de la Proteína Quinasa Activada por Mitógenos/metabolismo , Síndromes Mielodisplásicos/enzimología , Síndromes Mielodisplásicos/patología , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidores , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Poliubiquitina/metabolismo , Proteína-Arginina N-Metiltransferasas/antagonistas & inhibidores , Proteína-Arginina N-Metiltransferasas/metabolismo , Proteolisis , Proteínas Represoras/antagonistas & inhibidores , Proteínas Represoras/metabolismo , UbiquitinaciónRESUMEN
PURPOSE OF REVIEW: The purpose of this review is to summarize the current understanding of germline mutations as they contribute to leukemia development and progression. We also discuss how these new insights may help improve clinical management of germline mutations associated with leukemia. RECENT FINDINGS: Germline mutations may represent important initial mutations in the development of leukemia where interaction with somatic mutations provide further hits in leukemic progression. In addition, germline mutations may also contribute to leukemogenesis by impacting bone marrow stem-cell microenvironment and immune cell development and function. SUMMARY: Leukemia is characterized by the clonal expansion of malignant cells secondary to somatic or germline mutations in a variety of genes. Understanding somatic mutations that drive leukemogenesis has drastically improved our knowledge of leukemia biology and led to novel therapeutic strategies. Advances have also been made in identifying germline mutations that may affect leukemic development and progression. This review will discuss the biological and clinical relationship of germline mutations with clonal hematopoiesis, bone marrow microenvironment, and immunity in the progression of leukemia.
Asunto(s)
Células de la Médula Ósea , Carcinogénesis , Mutación de Línea Germinal , Leucemia , Células Madre Neoplásicas , Nicho de Células Madre/genética , Microambiente Tumoral/genética , Células de la Médula Ósea/metabolismo , Células de la Médula Ósea/patología , Carcinogénesis/genética , Carcinogénesis/metabolismo , Carcinogénesis/patología , Humanos , Leucemia/genética , Leucemia/metabolismo , Leucemia/patología , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patologíaRESUMEN
Amino acid (AA) metabolism is involved in diverse cellular functions, including cell survival and growth, however it remains unclear how it regulates normal hematopoiesis versus leukemogenesis. Here, we report that knockout of Slc1a5 (ASCT2), a transporter of neutral AAs, especially glutamine, results in mild to moderate defects in bone marrow and mature blood cell development under steady state conditions. In contrast, constitutive or induced deletion of Slc1a5 decreases leukemia initiation and maintenance driven by the oncogene MLL-AF9 or Pten deficiency. Survival of leukemic mice is prolonged following Slc1a5 deletion, and pharmacological inhibition of ASCT2 also decreases leukemia development and progression in xenograft models of human acute myeloid leukemia. Mechanistically, loss of ASCT2 generates a global effect on cellular metabolism, disrupts leucine influx and mTOR signaling, and induces apoptosis in leukemic cells. Given the substantial difference in reliance on ASCT2-mediated AA metabolism between normal and malignant blood cells, this in vivo study suggests ASCT2 as a promising therapeutic target for the treatment of leukemia.
Asunto(s)
Sistema de Transporte de Aminoácidos ASC/fisiología , Aminoácidos/metabolismo , Leucemia Mieloide Aguda/metabolismo , Antígenos de Histocompatibilidad Menor/fisiología , Sistema de Transporte de Aminoácidos ASC/genética , Animales , Línea Celular Tumoral , Progresión de la Enfermedad , Hematopoyesis/genética , Xenoinjertos , Humanos , Leucemia Mieloide Aguda/patología , Ratones , Antígenos de Histocompatibilidad Menor/genéticaRESUMEN
Immature phenotypes of cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) limit the utility of these cells in clinical application and basic research. During cardiac development, postnatal cardiomyocytes experience high oxygen tension along with a concomitant downregulation of hypoxia-inducible factor 1α (HIF-1α), leading to increased fatty acid oxidation (FAO). We hypothesized that targeting HIF-1α alone or in combination with other metabolic regulators could promote the metabolic maturation of hiPSC-CMs. We examined the effect of HIF-1α inhibition on the maturation of hiPSC-CMs and investigated a multipronged approach to promote hiPSC-CM maturation by combining HIF-1α inhibition with molecules that target key pathways involved in the energy metabolism. Cardiac spheres of highly-enriched hiPSC-CMs were treated with a HIF-1α inhibitor alone or in combination with an agonist of peroxisome proliferator activated receptor α (PPARα) and three postnatal factors (triiodothyronine hormone T3, insulin-like growth factor-1 and dexamethasone). HIF-1α inhibition significantly increased FAO and basal and maximal respiration of hiPSC-CMs. Combining HIF-1α inhibition with PPARα activation and the postnatal factors further increased FAO and improved mitochondrial maturation in hiPSC-CMs. Compared with mock-treated cultures, the cultures treated with the five factors had increased mitochondrial content and contained more cells with mitochondrial distribution throughout the cells, which are features of more mature cardiomyocytes. Consistent with these observations, a number of transcriptional regulators of mitochondrial metabolic processes were upregulated in hiPSC-CMs treated with the five factors. Furthermore, these cells had significantly increased Ca2+ transient kinetics and contraction and relaxation velocities, which are functional features for more mature cardiomyocytes. Therefore, targeting HIF-1α in combination with other metabolic regulators significantly improves the metabolic maturation of hiPSC-CMs.
Asunto(s)
Benzamidas/farmacología , Sinergismo Farmacológico , Subunidad alfa del Factor 1 Inducible por Hipoxia/antagonistas & inhibidores , Células Madre Pluripotentes Inducidas/fisiología , Mitocondrias/metabolismo , Miocitos Cardíacos/fisiología , PPAR alfa/agonistas , Antiinflamatorios/farmacología , Calcio/metabolismo , Diferenciación Celular , Células Cultivadas , Dexametasona/farmacología , Metabolismo Energético , Ácidos Grasos/química , Ácidos Grasos/metabolismo , Humanos , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/efectos de los fármacos , Factor I del Crecimiento Similar a la Insulina/farmacología , Metabolismo de los Lípidos , Mitocondrias/efectos de los fármacos , Miocitos Cardíacos/citología , Miocitos Cardíacos/efectos de los fármacos , Oxidación-Reducción , Transcriptoma , Triyodotironina/farmacologíaRESUMEN
Hematopoietic stem cell (HSC) quiescence is a tightly regulated process crucial for hematopoietic regeneration, which requires a healthy and supportive microenvironmental niche within the bone marrow (BM). Here, we show that deletion of Ptpn21, a protein tyrosine phosphatase highly expressed in HSCs, induces stem cell egress from the niche due to impaired retention within the BM. Ptpn21-/- HSCs exhibit enhanced mobility, decreased quiescence, increased apoptosis, and defective reconstitution capacity. Ptpn21 deletion also decreased HSC stiffness and increased physical deformability, in part by dephosphorylating Spetin1 (Tyr246), a poorly described component of the cytoskeleton. Elevated phosphorylation of Spetin1 in Ptpn21-/- cells impaired cytoskeletal remodeling, contributed to cortical instability, and decreased cell rigidity. Collectively, these findings show that Ptpn21 maintains cellular mechanics, which is correlated with its important functions in HSC niche retention and preservation of hematopoietic regeneration capacity.
Asunto(s)
Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Homeostasis , Proteínas Tirosina Fosfatasas no Receptoras/metabolismo , Septinas/metabolismo , Animales , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fosforilación , Proteínas Tirosina Fosfatasas no Receptoras/deficiencia , Nicho de Células MadreRESUMEN
The Src homology-2 domain-containing tyrosine phosphatase 2 (SHP-2) regulates many cellular processes, including proliferation, differentiation and survival. Polymorphisms in the gene encoding SHP-2 are associated with an increased susceptibility to develop ulcerative colitis. We recently reported that intestinal epithelial cell (IEC)-specific deletion of Shp-2 in mice (Shp-2IEC-KO ) leads to chronic colitis and colitis-associated cancer. This suggests that SHP-2-dependent signaling protects the colonic epithelium against inflammation and colitis-associated cancer development. To verify this hypothesis, we generated mice expressing the Shp-2 E76K activated form specifically in IEC. Our results showed that sustained Shp-2 activation in IEC increased intestine and crypt length, correlating with increased cell proliferation and migration. Crypt regeneration capacity was also markedly enhanced, as revealed by ex vivo organoid culture. Shp-2 activation alters the secretory cell lineage, as evidenced by increased goblet cell numbers and mucus secretion. Notably, these mice also demonstrated elevated ERK signaling in IEC and exhibited resistance against both chemical- and Citrobacter rodentium-induced colitis. In contrast, mice with IEC-specific Shp-2 deletion displayed reduced ERK signaling and rapidly developed chronic colitis. Remarkably, expression of an activated form of Braf in Shp-2-deficient mice restored ERK activation, goblet cell production and prevented colitis. Altogether, our results indicate that chronic activation of Shp-2/ERK signaling in the colonic epithelium confers resistance to mucosal erosion and colitis. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Asunto(s)
Movimiento Celular , Proliferación Celular , Colitis/prevención & control , Colon/enzimología , Células Caliciformes/enzimología , Proteína Tirosina Fosfatasa no Receptora Tipo 11/metabolismo , Regeneración , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Colitis/enzimología , Colitis/genética , Colitis/patología , Colon/patología , Modelos Animales de Enfermedad , Activación Enzimática , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Células Caliciformes/patología , Ratones Transgénicos , Fenotipo , Proteína Tirosina Fosfatasa no Receptora Tipo 11/genética , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas B-raf/metabolismo , Transducción de Señal , Técnicas de Cultivo de Tejidos , Cicatrización de HeridasRESUMEN
Genetic mutations in the phosphatase PTPN11 (SHP2) are associated with childhood leukemias. These mutations cause hyperactivation of SHP2 due to the disruption of the autoinhibitory conformation. By targeting the activation-associated protein conformational change, we have identified an SHP2 inhibitor ( E)-1-(1-(5-(3-(2,4-dichlorophenyl)acryloyl)-2-ethoxy-4-hydroxybenzyl)-1,2,5,6-tetrahydropyridin-3-yl)-1 H-benzo[ d]imidazol-2(3 H)-one (LY6, 1) using computer-aided drug design database screening combined with cell-based assays. This compound inhibited SHP2 with an IC50 value of 9.8 µM, 7-fold more selective for SHP2 than the highly related SHP1. Fluorescence titration, thermal shift, and microscale thermophoresis quantitative binding assays confirmed its direct binding to SHP2. This compound was further verified to effectively inhibit SHP2-mediated cell signaling and proliferation. Furthermore, mouse and patient leukemia cells with PTPN11 activating mutations were more sensitive to this inhibitor than wild-type cells. This small molecule SHP2 inhibitor has a potential to serve as a lead compound for further optimization studies to develop novel anti-SHP2 therapeutic agents.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Proteína Tirosina Fosfatasa no Receptora Tipo 11/antagonistas & inhibidores , Bibliotecas de Moléculas Pequeñas/farmacología , Animales , Sitios de Unión , Células Cultivadas , Diseño de Fármacos , Inhibidores Enzimáticos/química , Estabilidad de Enzimas , Ensayos Analíticos de Alto Rendimiento , Humanos , Ratones , Simulación de Dinámica Molecular , Estructura Molecular , Mutación , Conformación Proteica , Proteína Tirosina Fosfatasa no Receptora Tipo 11/química , Proteína Tirosina Fosfatasa no Receptora Tipo 11/genética , Transducción de Señal/efectos de los fármacos , Bibliotecas de Moléculas Pequeñas/químicaRESUMEN
While deregulation of mitochondrial metabolism and cytosolic glycolysis has been well recognized in tumor cells, the role of coordinated mitochondrial oxidation and cytosolic fermentation of pyruvate, a key metabolite derived from glucose, in physiological processes is not well understood. Here, we report that knockout of PTPMT1, a mitochondrial phosphoinositide phosphatase, completely blocked postnatal cerebellar development. Proliferation of granule cell progenitors, the most actively replicating cells in the developing cerebellum, was only moderately decreased, and proliferation of Purkinje cell progenitors did not seem to be affected in knockout mice. In contrast, generation of functional Bergmann glia from multipotent precursor cells (radial glia), which is essential for cerebellar corticogenesis, was totally disrupted. Moreover, despite a low turnover rate, neural stem cells were impaired in self-renewal in knockout mice. Mechanistically, loss of PTPMT1 decreased mitochondrial aerobic metabolism by limiting utilization of pyruvate, which resulted in bioenergetic stress in neural precursor/stem cells but not in progenitor or mature cells, leading to cell cycle arrest through activation of the AMPK-p19/p21 pathway. This study suggests that mitochondrial oxidation of the carbohydrate fuel is required for postnatal cerebellar development, and identifies a bioenergetic stress-induced cell cycle checkpoint in neural precursor/stem cells.
Asunto(s)
Metabolismo de los Hidratos de Carbono/fisiología , Cerebelo/crecimiento & desarrollo , Cerebelo/metabolismo , Mitocondrias/metabolismo , Células-Madre Neurales/fisiología , Animales , Animales Recién Nacidos , Puntos de Control del Ciclo Celular/genética , Cerebelo/citología , Femenino , Glucólisis , Masculino , Ratones Noqueados , Células-Madre Neurales/citología , Fosfohidrolasa PTEN/genética , Fosfohidrolasa PTEN/metabolismo , Ácido Pirúvico/metabolismoRESUMEN
The relationship between the hematopoietic stem cell (HSC) population and its surrounding bone marrow microenvironment is a rapidly evolving area of research. Normal HSC processes rely heavily on a complex communication network involving various marrow niches. Although leukemogenesis largely results from abnormal genetic activity within the leukemia stem cell itself, mounting evidence indicates a significant contributory role played by marrow niche dysregulation. Furthermore, numerous instances of activating or inactivating germline mutations within marrow microenvironment cells have been shown to be sufficient for development of myelodysplastic syndrome, myeloproliferative neoplasm, and acute myeloid leukemia, even in the context of wild-type HSCs. Recent evidence suggests that targeting aberrant chemokine production from germline-mutated marrow stromal cells can potentially reverse the process of leukemogenesis. This elaborate interplay between the HSC population and the marrow microenvironment allows for a number of unique clinical possibilities in efforts to induce remission, enhance chemosensitivity, manage relapsed disease, and prevent leukemia development, both in de novo and germline mutation-associated leukemias, including the use of targeted cytokine/chemokine inhibitors, immune checkpoint blockade, CXCR4/CXCL12 axis antagonists, and combined allogeneic HSC and mesenchymal stem cell transplantation. In this review, we discuss the pathways underlying normal and abnormal bone marrow niche functioning, the relationship between germline mutations in the stem cell microenvironment and dysregulated hematopoiesis, and future clinical perspectives that may be particularly applicable to prevention and treatment of germline-associated leukemias.
Asunto(s)
Médula Ósea/inmunología , Mutación de Línea Germinal , Neoplasias Hematológicas/genética , Hematopoyesis/genética , Síndromes Mielodisplásicos/genética , Trastornos Mieloproliferativos/genética , Nicho de Células Madre/inmunología , Animales , Antineoplásicos Inmunológicos/uso terapéutico , Médula Ósea/efectos de los fármacos , Médula Ósea/patología , Quimiocina CXCL12/genética , Quimiocina CXCL12/inmunología , Neoplasias Hematológicas/inmunología , Neoplasias Hematológicas/patología , Neoplasias Hematológicas/terapia , Hematopoyesis/inmunología , Trasplante de Células Madre Hematopoyéticas/métodos , Células Madre Hematopoyéticas/efectos de los fármacos , Células Madre Hematopoyéticas/inmunología , Células Madre Hematopoyéticas/patología , Humanos , Trasplante de Células Madre Mesenquimatosas/métodos , Síndromes Mielodisplásicos/inmunología , Síndromes Mielodisplásicos/patología , Síndromes Mielodisplásicos/terapia , Trastornos Mieloproliferativos/inmunología , Trastornos Mieloproliferativos/patología , Trastornos Mieloproliferativos/terapia , Receptores CXCR4/genética , Receptores CXCR4/inmunología , Recurrencia , Nicho de Células Madre/genética , Trasplante HomólogoRESUMEN
Myelodysplastic syndromes (MDS) are heterogeneous hematopoietic disorders that are incurable with conventional therapy. Their incidence is increasing with global population aging. Although many genetic, epigenetic, splicing, and metabolic aberrations have been identified in patients with MDS, their clinical features are quite similar. Here, we show that hypoxia-independent activation of hypoxia-inducible factor 1α (HIF1A) signaling is both necessary and sufficient to induce dysplastic and cytopenic MDS phenotypes. The HIF1A transcriptional signature is generally activated in MDS patient bone marrow stem/progenitors. Major MDS-associated mutations (Dnmt3a, Tet2, Asxl1, Runx1, and Mll1) activate the HIF1A signature. Although inducible activation of HIF1A signaling in hematopoietic cells is sufficient to induce MDS phenotypes, both genetic and chemical inhibition of HIF1A signaling rescues MDS phenotypes in a mouse model of MDS. These findings reveal HIF1A as a central pathobiologic mediator of MDS and as an effective therapeutic target for a broad spectrum of patients with MDS.Significance: We showed that dysregulation of HIF1A signaling could generate the clinically relevant diversity of MDS phenotypes by functioning as a signaling funnel for MDS driver mutations. This could resolve the disconnection between genotypes and phenotypes and provide a new clue as to how a variety of driver mutations cause common MDS phenotypes. Cancer Discov; 8(11); 1438-57. ©2018 AACR. See related commentary by Chen and Steidl, p. 1355 This article is highlighted in the In This Issue feature, p. 1333.
Asunto(s)
Subunidad alfa 2 del Factor de Unión al Sitio Principal/fisiología , N-Metiltransferasa de Histona-Lisina/fisiología , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/fisiología , Hipoxia/fisiopatología , Síndromes Mielodisplásicos/patología , Proteína de la Leucemia Mieloide-Linfoide/fisiología , Animales , Regulación Neoplásica de la Expresión Génica , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Metaboloma , Ratones , Ratones Noqueados , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/metabolismoRESUMEN
Platinum-based chemotherapeutics represent a mainstay of cancer therapy, but resistance limits their curative potential. Through a kinome RNAi screen, we identified microtubule-associated serine/threonine kinase 1 (MAST1) as a main driver of cisplatin resistance in human cancers. Mechanistically, cisplatin but no other DNA-damaging agents inhibit the MAPK pathway by dissociating cRaf from MEK1, while MAST1 replaces cRaf to reactivate the MAPK pathway in a cRaf-independent manner. We show clinical evidence that expression of MAST1, both initial and cisplatin-induced, contributes to platinum resistance and worse clinical outcome. Targeting MAST1 with lestaurtinib, a recently identified MAST1 inhibitor, restores cisplatin sensitivity, leading to the synergistic attenuation of cancer cell proliferation and tumor growth in human cancer cells and patient-derived xenograft models.