RESUMEN
Therapy resistance and metastasis, the most fatal steps in cancer, are often triggered by a (partial) activation of the epithelial-mesenchymal transition (EMT) programme. A mesenchymal phenotype predisposes to ferroptosis, a cell death pathway exerted by an iron and oxygen-radical-mediated peroxidation of phospholipids containing polyunsaturated fatty acids. We here show that various forms of EMT activation, including TGFß stimulation and acquired therapy resistance, increase ferroptosis susceptibility in cancer cells, which depends on the EMT transcription factor Zeb1. We demonstrate that Zeb1 increases the ratio of phospholipids containing pro-ferroptotic polyunsaturated fatty acids over cyto-protective monounsaturated fatty acids by modulating the differential expression of the underlying crucial enzymes stearoyl-Co-A desaturase 1 (SCD), fatty acid synthase (FASN), fatty acid desaturase 2 (FADS2), elongation of very long-chain fatty acid 5 (ELOVL5) and long-chain acyl-CoA synthetase 4 (ACSL4). Pharmacological inhibition of selected lipogenic enzymes (SCD and FADS2) allows the manipulation of ferroptosis sensitivity preferentially in high-Zeb1-expressing cancer cells. Our data are of potential translational relevance and suggest a combination of ferroptosis activators and SCD inhibitors for the treatment of aggressive cancers expressing high Zeb1.
RESUMEN
Ferroptosis is a pervasive non-apoptotic form of cell death highly relevant in various degenerative diseases and malignancies. The hallmark of ferroptosis is uncontrolled and overwhelming peroxidation of polyunsaturated fatty acids contained in membrane phospholipids, which eventually leads to rupture of the plasma membrane. Ferroptosis is unique in that it is essentially a spontaneous, uncatalyzed chemical process based on perturbed iron and redox homeostasis contributing to the cell death process, but that it is nonetheless modulated by many metabolic nodes that impinge on the cells' susceptibility to ferroptosis. Among the various nodes affecting ferroptosis sensitivity, several have emerged as promising candidates for pharmacological intervention, rendering ferroptosis-related proteins attractive targets for the treatment of numerous currently incurable diseases. Herein, the current members of a Germany-wide research consortium focusing on ferroptosis research, as well as key external experts in ferroptosis who have made seminal contributions to this rapidly growing and exciting field of research, have gathered to provide a comprehensive, state-of-the-art review on ferroptosis. Specific topics include: basic mechanisms, in vivo relevance, specialized methodologies, chemical and pharmacological tools, and the potential contribution of ferroptosis to disease etiopathology and progression. We hope that this article will not only provide established scientists and newcomers to the field with an overview of the multiple facets of ferroptosis, but also encourage additional efforts to characterize further molecular pathways modulating ferroptosis, with the ultimate goal to develop novel pharmacotherapies to tackle the various diseases associated with - or caused by - ferroptosis.
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Ferroptosis , Humanos , Animales , Hierro/metabolismo , Neoplasias/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Peroxidación de Lípido , Oxidación-Reducción , Susceptibilidad a EnfermedadesRESUMEN
The EMT-transcription factor ZEB1 is heterogeneously expressed in tumor cells and in cancer-associated fibroblasts (CAFs) in colorectal cancer (CRC). While ZEB1 in tumor cells regulates metastasis and therapy resistance, its role in CAFs is largely unknown. Combining fibroblast-specific Zeb1 deletion with immunocompetent mouse models of CRC, we observe that inflammation-driven tumorigenesis is accelerated, whereas invasion and metastasis in sporadic cancers are reduced. Single-cell transcriptomics, histological characterization, and in vitro modeling reveal a crucial role of ZEB1 in CAF polarization, promoting myofibroblastic features by restricting inflammatory activation. Zeb1 deficiency impairs collagen deposition and CAF barrier function but increases NFκB-mediated cytokine production, jointly promoting lymphocyte recruitment and immune checkpoint activation. Strikingly, the Zeb1-deficient CAF repertoire sensitizes to immune checkpoint inhibition, offering a therapeutic opportunity of targeting ZEB1 in CAFs and its usage as a prognostic biomarker. Collectively, we demonstrate that ZEB1-dependent plasticity of CAFs suppresses anti-tumor immunity and promotes metastasis.
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Fibroblastos Asociados al Cáncer , Neoplasias Colorrectales , Inmunoterapia , Inflamación , Homeobox 1 de Unión a la E-Box con Dedos de Zinc , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismo , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/genética , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/terapia , Neoplasias Colorrectales/inmunología , Animales , Ratones , Fibroblastos Asociados al Cáncer/metabolismo , Fibroblastos Asociados al Cáncer/patología , Humanos , Inflamación/metabolismo , Inflamación/genética , Inflamación/patología , Inmunoterapia/métodos , Regulación Neoplásica de la Expresión Génica , Fibroblastos/metabolismo , Línea Celular Tumoral , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Transición Epitelial-Mesenquimal/genéticaRESUMEN
Emerging evidence implicates the epithelial-mesenchymal transition transcription factor Zeb1 as a critical regulator of hematopoietic stem cell (HSC) differentiation. Whether Zeb1 regulates long-term maintenance of HSC function remains an open question. Using an inducible Mx-1-Cre mouse model that deletes conditional Zeb1 alleles in the adult hematopoietic system, we found that mice engineered to be deficient in Zeb1 for 32 weeks displayed expanded immunophenotypically defined adult HSCs and multipotent progenitors associated with increased abundance of lineage-biased/balanced HSC subsets and augmented cell survival characteristics. During hematopoietic differentiation, persistent Zeb1 loss increased B cells in the bone marrow and spleen and decreased monocyte generation in the peripheral blood. In competitive transplantation experiments, we found that HSCs from adult mice with long-term Zeb1 deletion displayed a cell autonomous defect in multilineage differentiation capacity. Long-term Zeb1 loss perturbed extramedullary hematopoiesis characterized by increased splenic weight and a paradoxical reduction in splenic cellularity that was accompanied by HSC exhaustion, lineage-specific defects, and an accumulation of aberrant, preleukemic like c-kit+CD16/32+ progenitors. Loss of Zeb1 for up to 42 weeks can lead to progressive splenomegaly and an accumulation of Gr-1+Mac-1+ cells, further supporting the notion that long-term expression of Zeb1 suppresses preleukemic activity. Thus, sustained Zeb1 deletion disrupts HSC functionality in vivo and impairs regulation of extramedullary hematopoiesis with potential implications for tumor suppressor functions of Zeb1 in myeloid neoplasms.
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Hematopoyesis Extramedular , Células Madre Hematopoyéticas , Homeobox 1 de Unión a la E-Box con Dedos de Zinc , Animales , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/genética , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismo , Ratones , Células Madre Hematopoyéticas/metabolismo , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/patología , Hematopoyesis Extramedular/genética , Diferenciación Celular , Ratones Noqueados , Bazo/metabolismo , Bazo/patología , Bazo/citología , Células Madre Adultas/metabolismo , Linaje de la CélulaRESUMEN
Epithelial-mesenchymal transition (EMT) constitutes an important pathway in organ fibrosis seen in the lungs, liver, eye, and salivary glands. This review summarizes the EMT observed within the lacrimal gland during its development, tissue damage and repair along with possible translational implications. Existing animal and human studies have reported the increased expression of EMT regulators i.e., transcription factors like Snail, TGF-ß1 within the lacrimal glands, and a possible role of reactive oxygen species, which might be initiating the cascade of EMT. In these studies, EMT is typically detected by reduced E-cadherin expression in the epithelial cells and increased Vimentin and Snail expression within the lacrimal glands' myoepithelial or ductal epithelial cells. Other than specific markers, electron microscopic evidence of disrupted basal lamina, increased collagen deposition, reorganised cytoskeleton of myoepithelial cells also indicated EMT. Very few studies have shown myoepithelial cells to be the cells transitioning into mesenchymal cells with increased extracellular matrix deposition within the lacrimal glands. EMT in animal models seemed reversible as glands got repaired after damage with IL-1α injection or duct ligation and transiently used the EMT as a means for tissue repair. The EMT cells also expressed nestin, a marker for progenitor cells in a rabbit duct ligation model. However, lacrimal glands of ocular graft versus host disease and IgG4 dacryoadenitis demonstrate irreversible acinar atrophy along with signs of EMT-fibrosis, reduced E-cadherin, and increased Vimentin and Snail expression. Future studies exploring the molecular mechanisms of EMT and thereby developing targeted therapies capable of transforming the mesenchymal cells into epithelial cells or blocking the EMT might help in the restoration of the lacrimal gland function.
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Aparato Lagrimal , Animales , Humanos , Conejos , Aparato Lagrimal/metabolismo , Transición Epitelial-Mesenquimal , Vimentina/metabolismo , Fibrosis , Cadherinas/metabolismo , Morfogénesis , Células Epiteliales/metabolismoRESUMEN
Osteoclasts are bone-resorbing polykaryons responsible for skeletal remodeling during health and disease. Coincident with their differentiation from myeloid precursors, osteoclasts undergo extensive transcriptional and metabolic reprogramming in order to acquire the cellular machinery necessary to demineralize bone and digest its interwoven extracellular matrix. While attempting to identify new regulatory molecules critical to bone resorption, we discovered that murine and human osteoclast differentiation is accompanied by the expression of Zeb1, a zinc-finger transcriptional repressor whose role in normal development is most frequently linked to the control of epithelial-mesenchymal programs. However, following targeting, we find that Zeb1 serves as an unexpected regulator of osteoclast energy metabolism. In vivo, Zeb1-null osteoclasts assume a hyperactivated state, markedly decreasing bone density due to excessive resorptive activity. Mechanistically, Zeb1 acts in a rheostat-like fashion to modulate murine and human osteoclast activity by transcriptionally repressing an ATP-buffering enzyme, mitochondrial creatine kinase 1 (MtCK1), thereby controlling the phosphocreatine energy shuttle and mitochondrial respiration. Together, these studies identify a novel Zeb1/MtCK1 axis that exerts metabolic control over bone resorption in vitro and in vivo.
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Resorción Ósea , Osteoclastos , Ratones , Animales , Humanos , Osteoclastos/metabolismo , Forma Mitocondrial de la Creatina-Quinasa/metabolismo , Resorción Ósea/genética , Resorción Ósea/metabolismo , Huesos , Diferenciación Celular , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/genética , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismoRESUMEN
The DNA damage response (DDR) and epithelial-to-mesenchymal transition (EMT) are two crucial cellular programs in cancer biology. While the DDR orchestrates cell-cycle progression, DNA repair, and cell death, EMT promotes invasiveness, cellular plasticity, and intratumor heterogeneity. Therapeutic targeting of EMT transcription factors, such as ZEB1, remains challenging, but tumor-promoting DDR alterations elicit specific vulnerabilities. Using multi-omics, inhibitors, and high-content microscopy, we discover a chemoresistant ZEB1-high-expressing sub-population (ZEB1hi) with co-rewired cell-cycle progression and proficient DDR across tumor entities. ZEB1 stimulates accelerated S-phase entry via CDK6, inflicting endogenous DNA replication stress. However, DDR buildups involving constitutive MRE11-dependent fork resection allow homeostatic cycling and enrichment of ZEB1hi cells during transforming growth factor ß (TGF-ß)-induced EMT and chemotherapy. Thus, ZEB1 promotes G1/S transition to launch a progressive DDR benefitting stress tolerance, which concurrently manifests a targetable vulnerability in chemoresistant ZEB1hi cells. Our study thus highlights the translationally relevant intercept of the DDR and EMT.
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Factores de Transcripción , Homeobox 1 de Unión a la E-Box con Dedos de Zinc , Factores de Transcripción/metabolismo , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/genética , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismo , Línea Celular Tumoral , Transición Epitelial-Mesenquimal/genética , Replicación del ADNRESUMEN
The ZEB2 transcription factor has been demonstrated to play important roles in hematopoiesis and leukemic transformation. ZEB1 is a close family member of ZEB2 but has remained more enigmatic concerning its roles in hematopoiesis. Here, we show using conditional loss-of-function approaches and bone marrow (BM) reconstitution experiments that ZEB1 plays a cell-autonomous role in hematopoietic lineage differentiation, particularly as a positive regulator of monocyte development in addition to its previously reported important role in T-cell differentiation. Analysis of existing single-cell (sc) RNA sequencing (RNA-seq) data of early hematopoiesis has revealed distinctive expression differences between Zeb1 and Zeb2 in hematopoietic stem and progenitor cell (HSPC) differentiation, with Zeb2 being more highly and broadly expressed than Zeb1 except at a key transition point (short-term HSC [ST-HSC]âMPP1), whereby Zeb1 appears to be the dominantly expressed family member. Inducible genetic inactivation of both Zeb1 and Zeb2 using a tamoxifen-inducible Cre-mediated approach leads to acute BM failure at this transition point with increased long-term and short-term hematopoietic stem cell numbers and an accompanying decrease in all hematopoietic lineage differentiation. Bioinformatics analysis of RNA-seq data has revealed that ZEB2 acts predominantly as a transcriptional repressor involved in restraining mature hematopoietic lineage gene expression programs from being expressed too early in HSPCs. ZEB1 appears to fine-tune this repressive role during hematopoiesis to ensure hematopoietic lineage fidelity. Analysis of Rosa26 locus-based transgenic models has revealed that Zeb1 as well as Zeb2 cDNA-based overexpression within the hematopoietic system can drive extramedullary hematopoiesis/splenomegaly and enhance monocyte development. Finally, inactivation of Zeb2 alone or Zeb1/2 together was found to enhance survival in secondary MLL-AF9 acute myeloid leukemia (AML) models attesting to the oncogenic role of ZEB1/2 in AML.
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Linaje de la Célula , Células Madre Hematopoyéticas/metabolismo , Leucemia Mieloide Aguda/metabolismo , Caja Homeótica 2 de Unión a E-Box con Dedos de Zinc/metabolismo , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismo , Animales , Células de la Médula Ósea/patología , Diferenciación Celular , Regulación Neoplásica de la Expresión Génica , Hematopoyesis , Células Madre Hematopoyéticas/patología , Leucemia Mieloide Aguda/patología , Ratones , Ratones Transgénicos , RNA-Seq , Caja Homeótica 2 de Unión a E-Box con Dedos de Zinc/genética , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/genéticaRESUMEN
The process of epithelial-mesenchymal transition (EMT) is fundamental for embryonic morphogenesis. Cells undergoing it lose epithelial characteristics and integrity, acquire mesenchymal features, and become motile. In cancer, this program is hijacked to confer essential changes in morphology and motility that fuel invasion. In addition, EMT is increasingly understood to orchestrate a large variety of complementary cancer features, such as tumor cell stemness, tumorigenicity, resistance to therapy and adaptation to changes in the microenvironment. In this review, we summarize recent findings related to these various classical and non-classical functions, and introduce EMT as a true tumorigenic multi-tool, involved in many aspects of cancer. We suggest that therapeutic targeting of the EMT process will-if acknowledging these complexities-be a possibility to concurrently interfere with tumor progression on many levels.
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Transición Epitelial-Mesenquimal , Neoplasias/etiología , Neoplasias/patología , Microambiente Tumoral , Animales , Biomarcadores , Transformación Celular Neoplásica , Progresión de la Enfermedad , Transición Epitelial-Mesenquimal/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias/metabolismo , Transducción de Señal , Microambiente Tumoral/genéticaRESUMEN
Radial glia-like (RGL) stem cells persist in the adult mammalian hippocampus, where they generate new neurons and astrocytes throughout life. The process of adult neurogenesis is well documented, but cell-autonomous factors regulating neuronal and astroglial differentiation are incompletely understood. Here, we evaluate the functions of the transcription factor zinc-finger E-box binding homeobox 1 (ZEB1) in adult hippocampal RGL cells using a conditional-inducible mouse model. We find that ZEB1 is necessary for self-renewal of active RGL cells. Genetic deletion of Zeb1 causes a shift toward symmetric cell division that consumes the RGL cell and generates pro-neuronal progenies, resulting in an increase of newborn neurons and a decrease of newly generated astrocytes. We identify ZEB1 as positive regulator of the ets-domain transcription factor ETV5 that is critical for asymmetric division.
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Autorrenovación de las Células/fisiología , Hipocampo/metabolismo , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismo , Animales , Diferenciación Celular/genética , Células Ependimogliales/metabolismo , Transición Epitelial-Mesenquimal/fisiología , Hipocampo/efectos de los fármacos , Humanos , Ratones , Neurogénesis/fisiología , Neuronas/metabolismoRESUMEN
Cytomegaloviruses (CMVs) have co-evolved with their mammalian hosts for millions of years, leading to remarkable host specificity and high infection prevalence. Macrophages, which already populate barrier tissues in the embryo, are the predominant immune cells at potential CMV entry sites. Here we show that, upon CMV infection, macrophages undergo a morphological, immunophenotypic, and metabolic transformation process with features of stemness, altered migration, enhanced invasiveness, and provision of the cell cycle machinery for viral proliferation. This complex process depends on Wnt signaling and the transcription factor ZEB1. In pulmonary infection, mouse CMV primarily targets and reprograms alveolar macrophages, which alters lung physiology and facilitates primary CMV and secondary bacterial infection by attenuating the inflammatory response. Thus, CMV profoundly perturbs macrophage identity beyond established limits of plasticity and rewires specific differentiation processes, allowing viral spread and impairing innate tissue immunity.
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Citomegalovirus/fisiología , Macrófagos Alveolares/virología , Animales , Presentación de Antígeno , Efecto Espectador , Ciclo Celular , Línea Celular Transformada , Reprogramación Celular , Citomegalovirus/patogenicidad , Citomegalovirus/ultraestructura , Infecciones por Citomegalovirus/inmunología , Infecciones por Citomegalovirus/virología , Proteínas Fluorescentes Verdes/metabolismo , Pulmón/patología , Macrófagos Alveolares/inmunología , Macrófagos Alveolares/ultraestructura , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Fenotipo , Células Madre/patología , Replicación Viral/fisiología , Vía de Señalización WntRESUMEN
The pancreas is comprised of exocrine and endocrine compartments releasing digestive enzymes into the duodenum and regulating blood glucose levels by insulin and glucagon release. Tissue homeostasis is depending on transcription factor networks, involving Ptf1α, Ngn3, Nkx6.1, and Sox9, which are already activated during organogenesis. However, proper organ function is challenged by diets of high sugar and fat content, increasing the risk of type 2 diabetes and other disorders. A detailed understanding of processes that are important for homeostasis and are impaired during type 2 diabetes is lacking. Here, we show that Zeb1-a transcription factor known for its pivotal role in epithelial-mesenchymal transition, cell plasticity, and metastasis in cancer-is expressed at low levels in epithelial cells of the pancreas and is crucial for organogenesis and pancreas function. Loss of Zeb1 in these cells result in an increase of islet mass, impaired glucose tolerance, and sensitizes to develop liver and pancreas steatosis during diabetes and obesity. Interestingly, moderate overexpression of Zeb1 results in severe pancreas agenesis and lethality after birth, due to islet insufficiency and lack of acinar structures. We show that Zeb1 induction interferes with proper differentiation, cell survival, and proliferation during pancreas formation, due to deregulated expression of endocrine-specific transcription factors. In summary, our analysis suggests a novel role of Zeb1 for homeostasis in epithelial cells that is indispensable for pancreas morphogenesis and proper organ function involving a tight regulation of Zeb1 expression.
RESUMEN
Osteosarcoma is an often-fatal mesenchyme-derived malignancy in children and young adults. Overexpression of EMT-transcription factors (EMT-TFs) has been associated with poor clinical outcome. Here, we demonstrated that the EMT-TF ZEB1 is able to block osteoblastic differentiation in normal bone development as well as in osteosarcoma cells. Consequently, overexpression of ZEB1 in osteosarcoma characterizes poorly differentiated, highly metastatic subgroups and its depletion induces differentiation of osteosarcoma cells. Overexpression of ZEB1 in osteosarcoma is frequently associated with silencing of the imprinted DLK-DIO3 locus, which encodes for microRNAs targeting ZEB1. Epigenetic reactivation of this locus in osteosarcoma cells reduces ZEB1 expression, induces differentiation, and sensitizes to standard treatment, thus indicating therapeutic options for ZEB1-driven osteosarcomas. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.
Asunto(s)
Neoplasias Óseas/patología , Regulación Neoplásica de la Expresión Génica , MicroARNs/genética , Osteosarcoma/patología , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismo , Animales , Desarrollo Óseo , Neoplasias Óseas/tratamiento farmacológico , Diferenciación Celular , Línea Celular , Proliferación Celular , Epigenómica , Expresión Génica , Humanos , Células Madre Mesenquimatosas/patología , Ratones , Osteoblastos/patología , Osteosarcoma/tratamiento farmacológico , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/genéticaRESUMEN
PURPOSE: To detect the immunohistochemical changes in the main lacrimal glands of patients suffering from chronic ocular sequelae of Stevens-Johnson syndrome (SJS). METHODS: Histological sections of biopsies from the lacrimal gland of three chronic SJS patients (mean age, 33 years; 2 males) with severe dry eye disease (Schirmer = 0 mm) were assessed using double immunofluorescence techniques. Changes in the expression of secretory proteins lactoferrin (Lf), lysozyme (Ly), aquaporin 5 (AQP5), S-100, and early apoptosis marker (Annexin V) were studied. RESULTS: Different morphological expressions of secretory proteins were present in the three samples. One sample had maintained the immunoreactivity for Lf, Ly, S-100, similar to healthy controls. Two samples had significantly reduced immunoreactivity for anti-Lf, anti-Ly, and S-100, the weakest being in the sample with distorted lobular architecture and mild interlobular fibrosis. AQP5 had a distinct vesicular intracytoplasmic immunoreactivity suggesting defective trafficking and integration of the protein to the apical membrane. There was no S-100 immunostaining in the acinar or ductal epithelium, whereas interstitial nerve fibers scattered in the periacinar region showed reduced immunoreactivity for S-100. There was strong Annexin V immunoreactivity in the nuclei of epithelial cells in the majority of acinar and ductal epithelia of all the samples, with distorted nuclear morphology in one sample. CONCLUSION: Defective trafficking of AQP5 and variable expression of Ly, Lf, S-100 are the notable findings in the lacrimal glands of chronic SJS patients along with signs of early apoptosis. It suggests that the palpebral lobe of the lacrimal gland is involved in the pathological processes occurring in the conjunctiva of SJS patients.
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Biomarcadores/metabolismo , Síndromes de Ojo Seco/metabolismo , Proteínas del Ojo/metabolismo , Aparato Lagrimal/metabolismo , Síndrome de Stevens-Johnson/complicaciones , Adulto , Anexina A5/metabolismo , Apoptosis , Acuaporina 5/metabolismo , Enfermedad Crónica , Síndromes de Ojo Seco/etiología , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Aparato Lagrimal/patología , Lactoferrina/metabolismo , Masculino , Muramidasa/metabolismo , Proteínas S100/metabolismo , Adulto JovenRESUMEN
Zeb1, a zinc finger E-box binding homeobox epithelial-mesenchymal transition (EMT) transcription factor, confers properties of "stemness," such as self-renewal, in cancer. Yet little is known about the function of Zeb1 in adult stem cells. Here, we used the hematopoietic system as a well-established paradigm of stem cell biology to evaluate Zeb1-mediated regulation of adult stem cells. We employed a conditional genetic approach using the Mx1-Cre system to specifically knock out (KO) Zeb1 in adult hematopoietic stem cells (HSCs) and their downstream progeny. Acute genetic deletion of Zeb1 led to rapid-onset thymic atrophy and apoptosis-driven loss of thymocytes and T cells. A profound cell-autonomous self-renewal defect and multilineage differentiation block were observed in Zeb1-KO HSCs. Loss of Zeb1 in HSCs activated transcriptional programs of deregulated HSC maintenance and multilineage differentiation genes and of cell polarity consisting of cytoskeleton-, lipid metabolism/lipid membrane-, and cell adhesion-related genes. Notably, epithelial cell adhesion molecule (EpCAM) expression was prodigiously upregulated in Zeb1-KO HSCs, which correlated with enhanced cell survival, diminished mitochondrial metabolism, ribosome biogenesis, and differentiation capacity and an activated transcriptomic signature associated with acute myeloid leukemia (AML) signaling. ZEB1 expression was downregulated in AML patients, and Zeb1 KO in the malignant counterparts of HSCs - leukemic stem cells (LSCs) - accelerated MLL-AF9- and Meis1a/Hoxa9-driven AML progression, implicating Zeb1 as a tumor suppressor in AML LSCs. Thus, Zeb1 acts as a transcriptional regulator in hematopoiesis, critically coordinating HSC self-renewal, apoptotic, and multilineage differentiation fates required to suppress leukemic potential in AML.
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Células Madre Hematopoyéticas/metabolismo , Leucemia Mieloide Aguda/metabolismo , Células Madre Neoplásicas/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismo , Animales , Eliminación de Gen , Células Madre Hematopoyéticas/patología , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Ratones , Ratones Noqueados , Células Madre Neoplásicas/patología , Proteínas Supresoras de Tumor/genética , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/genéticaRESUMEN
Invasion, metastasis and therapy resistance are the major cause of cancer-associated deaths, and the EMT-inducing transcription factor ZEB1 is a crucial stimulator of these processes. While work on ZEB1 has mainly focused on its role as a transcriptional repressor, it can also act as a transcriptional activator. To further understand these two modes of action, we performed a genome-wide ZEB1 binding study in triple-negative breast cancer cells. We identified ZEB1 as a novel interactor of the AP-1 factors FOSL1 and JUN and show that, together with the Hippo pathway effector YAP, they form a transactivation complex, predominantly activating tumour-promoting genes, thereby synergising with its function as a repressor of epithelial genes. High expression of ZEB1, YAP, FOSL1 and JUN marks the aggressive claudin-low subtype of breast cancer, indicating the translational relevance of our findings. Thus, our results link critical tumour-promoting transcription factors: ZEB1, AP-1 and Hippo pathway factors. Disturbing their molecular interaction may provide a promising treatment option for aggressive cancer types.
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Proteínas Adaptadoras Transductoras de Señales/metabolismo , Neoplasias de la Mama/metabolismo , Transición Epitelial-Mesenquimal , Genoma Humano , Factor de Transcripción AP-1/metabolismo , Factores de Transcripción/metabolismo , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Neoplasias de la Mama/genética , Línea Celular Tumoral , Femenino , Humanos , Proteínas Proto-Oncogénicas c-fos/genética , Proteínas Proto-Oncogénicas c-fos/metabolismo , Proteínas Proto-Oncogénicas c-jun/genética , Proteínas Proto-Oncogénicas c-jun/metabolismo , Factor de Transcripción AP-1/genética , Factores de Transcripción/genética , Proteínas Señalizadoras YAP , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/genéticaRESUMEN
Cleft lip and palate are common birth defects resulting from failure of the facial processes to fuse during development. The mammalian grainyhead-like (Grhl1-3) genes play key roles in a number of tissue fusion processes including neurulation, epidermal wound healing and eyelid fusion. One family member, Grhl2, is expressed in the epithelial lining of the first pharyngeal arch in mice at embryonic day (E)10.5, prompting analysis of the role of this factor in palatogenesis. Grhl2-null mice die at E11.5 with neural tube defects and a cleft face phenotype, precluding analysis of palatal fusion at a later stage of development. However, in the first pharyngeal arch of Grhl2-null embryos, dysregulation of transcription factors that drive epithelial-mesenchymal transition (EMT) occurs. The aberrant expression of these genes is associated with a shift in RNA-splicing patterns that favours the generation of mesenchymal isoforms of numerous regulators. Driving the EMT perturbation is loss of expression of the EMT-suppressing transcription factors Ovol1 and Ovol2, which are direct GRHL2 targets. The expression of the miR-200 family of microRNAs, also GRHL2 targets, is similarly reduced, resulting in a 56-fold upregulation of Zeb1 expression, a major driver of mesenchymal cellular identity. The critical role of GRHL2 in mediating cleft palate in Zeb1-/- mice is evident, with rescue of both palatal and facial fusion seen in Grhl2-/-;Zeb1-/- embryos. These findings highlight the delicate balance between GRHL2/ZEB1 and epithelial/mesenchymal cellular identity that is essential for normal closure of the palate and face. Perturbation of this pathway may underlie cleft palate in some patients.
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Embrión de Mamíferos/metabolismo , Hueso Paladar/embriología , Hueso Paladar/metabolismo , Factores de Transcripción/deficiencia , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/metabolismo , Animales , Región Branquial/embriología , Cadherinas/metabolismo , Cruzamientos Genéticos , Embrión de Mamíferos/ultraestructura , Epidermis/embriología , Epidermis/ultraestructura , Células Epiteliales/metabolismo , Transición Epitelial-Mesenquimal/genética , Epitelio/embriología , Femenino , Regulación del Desarrollo de la Expresión Génica , Masculino , Maxilar/embriología , Maxilar/patología , Mesodermo/embriología , Ratones , Ratones Noqueados , MicroARNs/genética , MicroARNs/metabolismo , Tamaño de los Órganos , Fenotipo , Embarazo , Empalme del ARN/genética , Factores de Transcripción/metabolismo , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/deficienciaRESUMEN
Epithelial-mesenchymal transition (EMT) is a crucial embryonic programme that is executed by various EMT transcription factors (EMT-TFs) and is aberrantly activated in cancer and other diseases. However, the causal role of EMT and EMT-TFs in different disease processes, especially cancer and metastasis, continues to be debated. In this Review, we identify and describe specific, non-redundant functions of the different EMT-TFs and discuss the reasons that may underlie disputes about EMT in cancer.
Asunto(s)
Transición Epitelial-Mesenquimal/genética , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Neoplasias/genética , Factores de Transcripción/genética , Animales , Desarrollo Embrionario/genética , Humanos , Modelos Genéticos , Neoplasias/patologíaRESUMEN
Directional migration is inherently important for epithelial tissue regeneration and repair, but how it is precisely controlled and coordinated with cell proliferation is unclear. Here, we report that Ovol2, a transcriptional repressor that inhibits epithelial-to-mesenchymal transition (EMT), plays a crucial role in adult skin epithelial regeneration and repair. Ovol2-deficient mice show compromised wound healing characterized by aberrant epidermal cell migration and proliferation, as well as delayed anagen progression characterized by defects in hair follicle matrix cell proliferation and subsequent differentiation. Epidermal keratinocytes and bulge hair follicle stem cells (Bu-HFSCs) lacking Ovol2 fail to expand in culture and display molecular alterations consistent with enhanced EMT and reduced proliferation. Live imaging of wound explants and Bu-HFSCs reveals increased migration speed but reduced directionality, and post-mitotic cell cycle arrest. Remarkably, simultaneous deletion of Zeb1 encoding an EMT-promoting factor restores directional migration to Ovol2-deficient Bu-HFSCs. Taken together, our findings highlight the important function of an Ovol2-Zeb1 EMT-regulatory circuit in controlling the directional migration of epithelial stem and progenitor cells to facilitate adult skin epithelial regeneration and repair.