RESUMO
During wound healing, different pools of stem cells (SCs) contribute to skin repair. However, how SCs become activated and drive the tissue remodeling essential for skin repair is still poorly understood. Here, by developing a mouse model allowing lineage tracing and basal cell lineage ablation, we monitor SC fate and tissue dynamics during regeneration using confocal and intravital imaging. Analysis of basal cell rearrangements shows dynamic transitions from a solid-like homeostatic state to a fluid-like state allowing tissue remodeling during repair, as predicted by a minimal mathematical modeling of the spatiotemporal dynamics and fate behavior of basal cells. The basal cell layer progressively returns to a solid-like state with re-epithelialization. Bulk, single-cell RNA, and epigenetic profiling of SCs, together with functional experiments, uncover a common regenerative state regulated by the EGFR/AP1 axis activated during tissue fluidization that is essential for skin SC activation and tissue repair.
RESUMO
During embryonic and postnatal development, organs and tissues grow steadily to achieve their final size at the end of puberty. However, little is known about the cellular dynamics that mediate postnatal growth. By combining in vivo clonal lineage tracing, proliferation kinetics, single-cell transcriptomics, and in vitro micro-pattern experiments, we resolved the cellular dynamics taking place during postnatal skin epidermis expansion. Our data revealed that harmonious growth is engineered by a single population of developmental progenitors presenting a fixed fate imbalance of self-renewing divisions with an ever-decreasing proliferation rate. Single-cell RNA sequencing revealed that epidermal developmental progenitors form a more uniform population compared with adult stem and progenitor cells. Finally, we found that the spatial pattern of cell division orientation is dictated locally by the underlying collagen fiber orientation. Our results uncover a simple design principle of organ growth where progenitors and differentiated cells expand in harmony with their surrounding tissues.
Assuntos
Células Epidérmicas/metabolismo , Epiderme/crescimento & desenvolvimento , Pele/crescimento & desenvolvimento , Animais , Animais não Endogâmicos , Diferenciação Celular/fisiologia , Divisão Celular/fisiologia , Linhagem da Célula/genética , Proliferação de Células/fisiologia , Células Cultivadas , Células Epidérmicas/patologia , Epiderme/metabolismo , Feminino , Masculino , Camundongos , Camundongos Transgênicos , Células-Tronco/citologiaRESUMO
Epithelial-mesenchymal transition (EMT) encompasses dynamic changes in cellular organization from epithelial to mesenchymal phenotypes, which leads to functional changes in cell migration and invasion. EMT occurs in a diverse range of physiological and pathological conditions and is driven by a conserved set of inducing signals, transcriptional regulators and downstream effectors. With over 5,700 publications indexed by Web of Science in 2019 alone, research on EMT is expanding rapidly. This growing interest warrants the need for a consensus among researchers when referring to and undertaking research on EMT. This Consensus Statement, mediated by 'the EMT International Association' (TEMTIA), is the outcome of a 2-year-long discussion among EMT researchers and aims to both clarify the nomenclature and provide definitions and guidelines for EMT research in future publications. We trust that these guidelines will help to reduce misunderstanding and misinterpretation of research data generated in various experimental models and to promote cross-disciplinary collaboration to identify and address key open questions in this research field. While recognizing the importance of maintaining diversity in experimental approaches and conceptual frameworks, we emphasize that lasting contributions of EMT research to increasing our understanding of developmental processes and combatting cancer and other diseases depend on the adoption of a unified terminology to describe EMT.
Assuntos
Pesquisa Biomédica/normas , Transição Epitelial-Mesenquimal , Animais , Movimento Celular , Plasticidade Celular , Consenso , Biologia do Desenvolvimento/normas , Humanos , Neoplasias/patologia , Terminologia como AssuntoRESUMO
The resistance of cancer cells to therapy is responsible for the death of most patients with cancer1. Epithelial-to-mesenchymal transition (EMT) has been associated with resistance to therapy in different cancer cells2,3. However, the mechanisms by which EMT mediates resistance to therapy remain poorly understood. Here, using a mouse model of skin squamous cell carcinoma undergoing spontaneous EMT during tumorigenesis, we found that EMT tumour cells are highly resistant to a wide range of anti-cancer therapies both in vivo and in vitro. Using gain and loss of function studies in vitro and in vivo, we found that RHOJ-a small GTPase that is preferentially expressed in EMT cancer cells-controls resistance to therapy. Using genome-wide transcriptomic and proteomic profiling, we found that RHOJ regulates EMT-associated resistance to chemotherapy by enhancing the response to replicative stress and activating the DNA-damage response, enabling tumour cells to rapidly repair DNA lesions induced by chemotherapy. RHOJ interacts with proteins that regulate nuclear actin, and inhibition of actin polymerization sensitizes EMT tumour cells to chemotherapy-induced cell death in a RHOJ-dependent manner. Together, our study uncovers the role and the mechanisms through which RHOJ acts as a key regulator of EMT-associated resistance to chemotherapy.
Assuntos
Carcinoma de Células Escamosas , Resistencia a Medicamentos Antineoplásicos , Transição Epitelial-Mesenquimal , Neoplasias Cutâneas , Proteínas rho de Ligação ao GTP , Actinas/efeitos dos fármacos , Actinas/metabolismo , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Proteômica , Proteínas rho de Ligação ao GTP/genética , Proteínas rho de Ligação ao GTP/metabolismo , Animais , Camundongos , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Perfilação da Expressão Gênica , GenomaRESUMO
Sympathetic activation during cold exposure increases adipocyte thermogenesis via the expression of mitochondrial protein uncoupling protein 1 (UCP1)1. The propensity of adipocytes to express UCP1 is under a critical influence of the adipose microenvironment and varies between sexes and among various fat depots2-7. Here we report that mammary gland ductal epithelial cells in the adipose niche regulate cold-induced adipocyte UCP1 expression in female mouse subcutaneous white adipose tissue (scWAT). Single-cell RNA sequencing shows that glandular luminal epithelium subtypes express transcripts that encode secretory factors controlling adipocyte UCP1 expression under cold conditions. We term these luminal epithelium secretory factors 'mammokines'. Using 3D visualization of whole-tissue immunofluorescence, we reveal sympathetic nerve-ductal contact points. We show that mammary ducts activated by sympathetic nerves limit adipocyte UCP1 expression via the mammokine lipocalin 2. In vivo and ex vivo ablation of mammary duct epithelium enhance the cold-induced adipocyte thermogenic gene programme in scWAT. Since the mammary duct network extends throughout most of the scWAT in female mice, females show markedly less scWAT UCP1 expression, fat oxidation, energy expenditure and subcutaneous fat mass loss compared with male mice, implicating sex-specific roles of mammokines in adipose thermogenesis. These results reveal a role of sympathetic nerve-activated glandular epithelium in adipocyte UCP1 expression and suggest that mammary duct luminal epithelium has an important role in controlling glandular adiposity.
Assuntos
Adipócitos , Tecido Adiposo Branco , Epitélio , Glândulas Mamárias Animais , Termogênese , Animais , Feminino , Masculino , Camundongos , Adipócitos/metabolismo , Tecido Adiposo Branco/citologia , Tecido Adiposo Branco/metabolismo , Epitélio/inervação , Epitélio/metabolismo , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo , Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/inervação , Glândulas Mamárias Animais/fisiologia , Temperatura Baixa , Sistema Nervoso Simpático/fisiologia , Metabolismo Energético , Oxirredução , Caracteres SexuaisRESUMO
Epithelial-to-mesenchymal transition (EMT) regulates tumour initiation, progression, metastasis and resistance to anti-cancer therapy1-7. Although great progress has been made in understanding the role of EMT and its regulatory mechanisms in cancer, no therapeutic strategy to pharmacologically target EMT has been identified. Here we found that netrin-1 is upregulated in a primary mouse model of skin squamous cell carcinoma (SCC) exhibiting spontaneous EMT. Pharmacological inhibition of netrin-1 by administration of NP137, a netrin-1-blocking monoclonal antibody currently used in clinical trials in human cancer (ClinicalTrials.gov identifier NCT02977195 ), decreased the proportion of EMT tumour cells in skin SCC, decreased the number of metastases and increased the sensitivity of tumour cells to chemotherapy. Single-cell RNA sequencing revealed the presence of different EMT states, including epithelial, early and late hybrid EMT, and full EMT states, in control SCC. By contrast, administration of NP137 prevented the progression of cancer cells towards a late EMT state and sustained tumour epithelial states. Short hairpin RNA knockdown of netrin-1 and its receptor UNC5B in EPCAM+ tumour cells inhibited EMT in vitro in the absence of stromal cells and regulated a common gene signature that promotes tumour epithelial state and restricts EMT. To assess the relevance of these findings to human cancers, we treated mice transplanted with the A549 human cancer cell line-which undergoes EMT following TGFß1 administration8,9-with NP137. Netrin-1 inhibition decreased EMT in these transplanted A549 cells. Together, our results identify a pharmacological strategy for targeting EMT in cancer, opening up novel therapeutic interventions for anti-cancer therapy.
Assuntos
Anticorpos Monoclonais , Carcinoma de Células Escamosas , Transição Epitelial-Mesenquimal , Netrina-1 , Neoplasias Cutâneas , Animais , Humanos , Camundongos , Células A549 , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Receptores de Netrina/antagonistas & inibidores , Receptores de Netrina/deficiência , Receptores de Netrina/genética , Netrina-1/antagonistas & inibidores , Netrina-1/deficiência , Netrina-1/genética , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/farmacologia , Modelos Animais de Doenças , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/patologia , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Metástase Neoplásica/tratamento farmacológico , Análise da Expressão Gênica de Célula Única , RNA-Seq , Molécula de Adesão da Célula Epitelial/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , Fator de Crescimento Transformador beta1/farmacologiaRESUMO
The skin epidermis is constantly renewed throughout life1,2. Disruption of the balance between renewal and differentiation can lead to uncontrolled growth and tumour initiation3. However, the ways in which oncogenic mutations affect the balance between renewal and differentiation and lead to clonal expansion, cell competition, tissue colonization and tumour development are unknown. Here, through multidisciplinary approaches that combine in vivo clonal analysis using intravital microscopy, single-cell analysis and functional analysis, we show how SmoM2-a constitutively active oncogenic mutant version of Smoothened (SMO) that induces the development of basal cell carcinoma-affects clonal competition and tumour initiation in real time. We found that expressing SmoM2 in the ear epidermis of mice induced clonal expansion together with tumour initiation and invasion. By contrast, expressing SmoM2 in the back-skin epidermis led to a clonal expansion that induced lateral cell competition without dermal invasion and tumour formation. Single-cell analysis showed that oncogene expression was associated with a cellular reprogramming of adult interfollicular cells into an embryonic hair follicle progenitor (EHFP) state in the ear but not in the back skin. Comparisons between the ear and the back skin revealed that the dermis has a very different composition in these two skin types, with increased stiffness and a denser collagen I network in the back skin. Decreasing the expression of collagen I in the back skin through treatment with collagenase, chronic UV exposure or natural ageing overcame the natural resistance of back-skin basal cells to undergoing EHFP reprogramming and tumour initiation after SmoM2 expression. Altogether, our study shows that the composition of the extracellular matrix regulates how susceptible different regions of the body are to tumour initiation and invasion.
Assuntos
Transformação Celular Neoplásica , Matriz Extracelular , Neoplasias Cutâneas , Microambiente Tumoral , Animais , Camundongos , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Colágeno/metabolismo , Epiderme/patologia , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Neoplasias Cutâneas/patologia , Carcinoma Basocelular/patologia , Orelha/patologia , Colagenases/metabolismo , Envelhecimento , Raios Ultravioleta , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismoRESUMO
Netrin-1 is upregulated in cancers as a protumoural mechanism1. Here we describe netrin-1 upregulation in a majority of human endometrial carcinomas (ECs) and demonstrate that netrin-1 blockade, using an anti-netrin-1 antibody (NP137), is effective in reduction of tumour progression in an EC mouse model. We next examined the efficacy of NP137, as a first-in-class single agent, in a Phase I trial comprising 14 patients with advanced EC. As best response we observed 8 stable disease (8 out of 14, 57.1%) and 1 objective response as RECIST v.1.1 (partial response, 1 out of 14 (7.1%), 51.16% reduction in target lesions at 6 weeks and up to 54.65% reduction during the following 6 months). To evaluate the NP137 mechanism of action, mouse tumour gene profiling was performed, and we observed, in addition to cell death induction, that NP137 inhibited epithelial-to-mesenchymal transition (EMT). By performing bulk RNA sequencing (RNA-seq), spatial transcriptomics and single-cell RNA-seq on paired pre- and on-treatment biopsies from patients with EC from the NP137 trial, we noted a net reduction in tumour EMT. This was associated with changes in immune infiltrate and increased interactions between cancer cells and the tumour microenvironment. Given the importance of EMT in resistance to current standards of care2, we show in the EC mouse model that a combination of NP137 with carboplatin-paclitaxel outperformed carboplatin-paclitaxel alone. Our results identify netrin-1 blockade as a clinical strategy triggering both tumour debulking and EMT inhibition, thus potentially alleviating resistance to standard treatments.
Assuntos
Neoplasias do Endométrio , Transição Epitelial-Mesenquimal , Netrina-1 , Animais , Feminino , Humanos , Camundongos , Biópsia , Carboplatina/administração & dosagem , Carboplatina/farmacologia , Carboplatina/uso terapêutico , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Neoplasias do Endométrio/tratamento farmacológico , Neoplasias do Endométrio/genética , Neoplasias do Endométrio/imunologia , Neoplasias do Endométrio/patologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Perfilação da Expressão Gênica , Netrina-1/antagonistas & inibidores , Paclitaxel/administração & dosagem , Paclitaxel/farmacologia , Paclitaxel/uso terapêutico , RNA-Seq , Análise da Expressão Gênica de Célula Única , Microambiente Tumoral/efeitos dos fármacosRESUMO
Although melanoma is notorious for its high degree of heterogeneity and plasticity1,2, the origin and magnitude of cell-state diversity remains poorly understood. Equally, it is unclear whether growth and metastatic dissemination are supported by overlapping or distinct melanoma subpopulations. Here, by combining mouse genetics, single-cell and spatial transcriptomics, lineage tracing and quantitative modelling, we provide evidence of a hierarchical model of tumour growth that mirrors the cellular and molecular logic underlying the cell-fate specification and differentiation of the embryonic neural crest. We show that tumorigenic competence is associated with a spatially localized perivascular niche, a phenotype acquired through an intercellular communication pathway established by endothelial cells. Consistent with a model in which only a fraction of cells are fated to fuel growth, temporal single-cell tracing of a population of melanoma cells with a mesenchymal-like state revealed that these cells do not contribute to primary tumour growth but, instead, constitute a pool of metastatic initiating cells that switch cell identity while disseminating to secondary organs. Our data provide a spatially and temporally resolved map of the diversity and trajectories of melanoma cell states and suggest that the ability to support growth and metastasis are limited to distinct pools of cells. The observation that these phenotypic competencies can be dynamically acquired after exposure to specific niche signals warrant the development of therapeutic strategies that interfere with the cancer cell reprogramming activity of such microenvironmental cues.
Assuntos
Proliferação de Células , Melanoma , Metástase Neoplásica , Animais , Comunicação Celular , Diferenciação Celular , Linhagem da Célula , Rastreamento de Células , Reprogramação Celular , Células Endoteliais , Melanoma/genética , Melanoma/patologia , Mesoderma/patologia , Camundongos , Metástase Neoplásica/patologia , Crista Neural/embriologia , Fenótipo , Análise de Célula Única , Transcriptoma , Microambiente TumoralRESUMO
Sweat glands are abundant in the body and essential for thermoregulation. Like mammary glands, they originate from epidermal progenitors. However, they display few signs of cellular turnover, and whether they have stem cells and tissue-regenerative capacity remains largely unexplored. Using lineage tracing, we here identify in sweat ducts multipotent progenitors that transition to unipotency after developing the sweat gland. In characterizing four adult stem cell populations of glandular skin, we show that they display distinct regenerative capabilities and remain unipotent when healing epidermal, myoepithelial-specific, and lumenal-specific injuries. We devise purification schemes and isolate and transcriptionally profile progenitors. Exploiting molecular differences between sweat and mammary glands, we show that only some progenitors regain multipotency to produce de novo ductal and glandular structures, but that these can retain their identity even within certain foreign microenvironments. Our findings provide insight into glandular stem cells and a framework for the further study of sweat gland biology.
Assuntos
Células-Tronco Adultas/citologia , Células-Tronco Adultas/fisiologia , Homeostase , Glândulas Sudoríparas/citologia , Cicatrização , Células-Tronco Adultas/classificação , Animais , Células Epidérmicas , Epiderme/fisiologia , Feminino , Humanos , Glândulas Mamárias Animais/citologia , Camundongos , Morfogênese , Células-Tronco Multipotentes/fisiologia , Análise de Componente Principal , Transplante de Células-Tronco , Glândulas Sudoríparas/embriologia , Glândulas Sudoríparas/fisiologiaRESUMO
FAT1, which encodes a protocadherin, is one of the most frequently mutated genes in human cancers1-5. However, the role and the molecular mechanisms by which FAT1 mutations control tumour initiation and progression are poorly understood. Here, using mouse models of skin squamous cell carcinoma and lung tumours, we found that deletion of Fat1 accelerates tumour initiation and malignant progression and promotes a hybrid epithelial-to-mesenchymal transition (EMT) phenotype. We also found this hybrid EMT state in FAT1-mutated human squamous cell carcinomas. Skin squamous cell carcinomas in which Fat1 was deleted presented increased tumour stemness and spontaneous metastasis. We performed transcriptional and chromatin profiling combined with proteomic analyses and mechanistic studies, which revealed that loss of function of FAT1 activates a CAMK2-CD44-SRC axis that promotes YAP1 nuclear translocation and ZEB1 expression that stimulates the mesenchymal state. This loss of function also inactivates EZH2, promoting SOX2 expression, which sustains the epithelial state. Our comprehensive analysis identified drug resistance and vulnerabilities in FAT1-deficient tumours, which have important implications for cancer therapy. Our studies reveal that, in mouse and human squamous cell carcinoma, loss of function of FAT1 promotes tumour initiation, progression, invasiveness, stemness and metastasis through the induction of a hybrid EMT state.
Assuntos
Caderinas/deficiência , Transição Epitelial-Mesenquimal/genética , Deleção de Genes , Metástase Neoplásica/genética , Neoplasias/genética , Neoplasias/patologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Caderinas/genética , Caderinas/metabolismo , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Progressão da Doença , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Humanos , Receptores de Hialuronatos/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Mesoderma/metabolismo , Mesoderma/patologia , Camundongos , Metástase Neoplásica/tratamento farmacológico , Neoplasias/tratamento farmacológico , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Fenótipo , Fosfoproteínas/análise , Fosfoproteínas/metabolismo , Proteômica , Fatores de Transcrição SOXB1/metabolismo , Transdução de Sinais , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Fatores de Transcrição/metabolismo , Proteínas de Sinalização YAP , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismo , Quinases da Família src/metabolismoRESUMO
Within a tumor, cancer cells exist in different states that are associated with distinct tumor functions, including proliferation, differentiation, invasion, metastasis, and resistance to anti-cancer therapy. The identification of the gene regulatory networks underpinning each state is essential for better understanding functional tumor heterogeneity and revealing tumor vulnerabilities. Here, we review the different studies identifying tumor states by single-cell sequencing approaches and the mechanisms that promote and sustain these functional states and regulate their transitions. We also describe how different tumor states are spatially distributed and interact with the specific stromal cells that compose the tumor microenvironment. Finally, we discuss how the understanding of tumor plasticity and transition states can be used to develop new strategies to improve cancer therapy.
Assuntos
Neoplasias/metabolismo , Análise de Célula Única/métodos , Animais , Humanos , Neoplasias/genética , Neoplasias/patologia , RNA-Seq/métodosRESUMO
The ability of the skin to grow in response to stretching has been exploited in reconstructive surgery1. Although the response of epidermal cells to stretching has been studied in vitro2,3, it remains unclear how mechanical forces affect their behaviour in vivo. Here we develop a mouse model in which the consequences of stretching on skin epidermis can be studied at single-cell resolution. Using a multidisciplinary approach that combines clonal analysis with quantitative modelling and single-cell RNA sequencing, we show that stretching induces skin expansion by creating a transient bias in the renewal activity of epidermal stem cells, while a second subpopulation of basal progenitors remains committed to differentiation. Transcriptional and chromatin profiling identifies how cell states and gene-regulatory networks are modulated by stretching. Using pharmacological inhibitors and mouse mutants, we define the step-by-step mechanisms that control stretch-mediated tissue expansion at single-cell resolution in vivo.
Assuntos
Mecanotransdução Celular/fisiologia , Análise de Célula Única , Pele/citologia , Pele/crescimento & desenvolvimento , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Junções Aderentes/metabolismo , Animais , Sequência de Bases , Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular/efeitos dos fármacos , Autorrenovação Celular/efeitos dos fármacos , Cromatina/efeitos dos fármacos , Cromatina/genética , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , Células Clonais/citologia , Células Clonais/efeitos dos fármacos , Células Clonais/metabolismo , Modelos Animais de Doenças , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Redes Reguladoras de Genes/efeitos dos fármacos , Hidrogéis/administração & dosagem , Hidrogéis/farmacologia , Mecanotransdução Celular/efeitos dos fármacos , Mecanotransdução Celular/genética , Camundongos , Camundongos Transgênicos , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Mutação , RNA Mensageiro/genética , RNA-Seq , Pele/efeitos dos fármacos , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Transativadores/antagonistas & inibidores , Transativadores/metabolismo , Fator de Transcrição AP-1/metabolismo , Transcrição Gênica/efeitos dos fármacos , Proteínas de Sinalização YAPRESUMO
Glandular epithelia, including the mammary and prostate glands, are composed of basal cells (BCs) and luminal cells (LCs)1,2. Many glandular epithelia develop from multipotent basal stem cells (BSCs) that are replaced in adult life by distinct pools of unipotent stem cells1,3-8. However, adult unipotent BSCs can reactivate multipotency under regenerative conditions and upon oncogene expression3,9-13. This suggests that an active mechanism restricts BSC multipotency under normal physiological conditions, although the nature of this mechanism is unknown. Here we show that the ablation of LCs reactivates the multipotency of BSCs from multiple epithelia both in vivo in mice and in vitro in organoids. Bulk and single-cell RNA sequencing revealed that, after LC ablation, BSCs activate a hybrid basal and luminal cell differentiation program before giving rise to LCs-reminiscent of the genetic program that regulates multipotency during embryonic development7. By predicting ligand-receptor pairs from single-cell data14, we find that TNF-which is secreted by LCs-restricts BC multipotency under normal physiological conditions. By contrast, the Notch, Wnt and EGFR pathways were activated in BSCs and their progeny after LC ablation; blocking these pathways, or stimulating the TNF pathway, inhibited regeneration-induced BC multipotency. Our study demonstrates that heterotypic communication between LCs and BCs is essential to maintain lineage fidelity in glandular epithelial stem cells.
Assuntos
Comunicação Celular , Células Epiteliais/citologia , Células-Tronco Multipotentes/citologia , Animais , Linhagem da Célula , Células Epiteliais/metabolismo , Receptores ErbB/metabolismo , Feminino , Homeostase , Humanos , Masculino , Glândulas Mamárias Animais/citologia , Camundongos , Células-Tronco Multipotentes/metabolismo , Organoides/citologia , Próstata/citologia , RNA Mensageiro/genética , RNA-Seq , Receptores Notch/metabolismo , Glândulas Salivares/citologia , Análise de Célula Única , Pele/citologia , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Wnt/metabolismoRESUMO
During embryonic and postnatal development, the different cells types that form adult tissues must be generated and specified in a precise temporal manner. During adult life, most tissues undergo constant renewal to maintain homeostasis. Lineage-tracing and genetic labelling technologies are beginning to shed light on the mechanisms and dynamics of stem and progenitor cell fate determination during development, tissue maintenance and repair, as well as their dysregulation in tumour formation. Statistical approaches, based on proliferation assays and clonal fate analyses, provide quantitative insights into cell kinetics and fate behaviour. These are powerful techniques to address new questions and paradigms in transgenic mouse models and other model systems.
Assuntos
Linhagem da Célula/fisiologia , Rastreamento de Células/métodos , Células-Tronco/fisiologia , Adulto , Animais , Humanos , Cinética , Camundongos , Camundongos Transgênicos , Modelos BiológicosRESUMO
Melanocytes present in hair follicles are responsible for their pigmentation. Melanocyte differentiation and hair pigmentation depend on the stem cell factor (SCF)/c-Kit signaling pathway, but the niche that regulates melanocyte differentiation is not well characterized. In this issue of Genes & Development, Liao and colleagues (pp. 744-756) identify Krox20+-derived cells of the hair shaft as the niche and the essential source of SCF required for melanocyte maturation. This study delineates the niche factors regulating melanocyte differentiation and hair pigmentation and opens up new avenues to further characterize the cross-talk between the hair follicle and melanocytes that controls melanocyte maintenance and differentiation.
Assuntos
Diferenciação Celular , Folículo Piloso/citologia , Melanócitos/citologia , Animais , Melanócitos/metabolismo , Pigmentação/genética , Pigmentação/fisiologia , Proteínas Proto-Oncogênicas c-kit/genética , Proteínas Proto-Oncogênicas c-kit/metabolismo , Transdução de Sinais , Fator de Células-Tronco/genética , Fator de Células-Tronco/metabolismoRESUMO
The increasing momentum of stem cell research continues, with the better characterization of induced pluripotent stem (iPS) cells, the conversion of differentiated cells into different cell types and the use of pluripotent stem cells to generate whole tissues, among other advances. Here, six experts in the field of stem cell research compare different stem cell models and highlight the importance of pursuing complementary experimental approaches for a better understanding of pluripotency and differentiation and an informed approach to medical applications.
Assuntos
Células-Tronco Embrionárias/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Pesquisa com Células-Tronco , Células-Tronco/citologia , Animais , Bioética , Diferenciação Celular , Humanos , Camundongos , Modelos Biológicos , Análise de Sequência com Séries de OligonucleotídeosRESUMO
Basal cell carcinoma (BCC) is the most frequent cancer in humans and results from constitutive activation of the Hedgehog pathway1. Several Smoothened inhibitors are used to treat Hedgehog-mediated malignancies, including BCC and medulloblastoma2. Vismodegib, a Smoothened inhibitor, leads to BCC shrinkage in the majority of patients with BCC3, but the mechanism by which it mediates BCC regression is unknown. Here we used two genetically engineered mouse models of BCC4 to investigate the mechanisms by which inhibition of Smoothened mediates tumour regression. We found that vismodegib mediates BCC regression by inhibiting a hair follicle-like fate and promoting the differentiation of tumour cells. However, a small population of tumour cells persists and is responsible for tumour relapse following treatment discontinuation, mimicking the situation found in humans5. In both mouse and human BCC, this persisting, slow-cycling tumour population expresses LGR5 and is characterized by active Wnt signalling. Combining Lgr5 lineage ablation or inhibition of Wnt signalling with vismodegib treatment leads to eradication of BCC. Our results show that vismodegib induces tumour regression by promoting tumour differentiation, and demonstrates that the synergy between Wnt and Smoothened inhibitors is a clinically relevant strategy for overcoming tumour relapse in BCC.
Assuntos
Anilidas/farmacologia , Anilidas/uso terapêutico , Carcinoma Basocelular/tratamento farmacológico , Carcinoma Basocelular/patologia , Recidiva Local de Neoplasia , Piridinas/farmacologia , Piridinas/uso terapêutico , Receptores Acoplados a Proteínas G/metabolismo , Anilidas/administração & dosagem , Animais , Carcinoma Basocelular/genética , Diferenciação Celular/efeitos dos fármacos , Linhagem da Célula/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Folículo Piloso/citologia , Folículo Piloso/efeitos dos fármacos , Proteínas Hedgehog/antagonistas & inibidores , Proteínas Hedgehog/metabolismo , Humanos , Masculino , Camundongos , Recidiva Local de Neoplasia/prevenção & controle , Receptor Patched-1/deficiência , Piridinas/administração & dosagem , Recidiva , Prevenção Secundária , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Receptor Smoothened/antagonistas & inibidores , Suspensão de Tratamento , Proteínas Wnt/antagonistas & inibidores , Proteínas Wnt/metabolismo , Via de Sinalização Wnt/efeitos dos fármacosRESUMO
In cancer, the epithelial-to-mesenchymal transition (EMT) is associated with tumour stemness, metastasis and resistance to therapy. It has recently been proposed that, rather than being a binary process, EMT occurs through distinct intermediate states. However, there is no direct in vivo evidence for this idea. Here we screen a large panel of cell surface markers in skin and mammary primary tumours, and identify the existence of multiple tumour subpopulations associated with different EMT stages: from epithelial to completely mesenchymal states, passing through intermediate hybrid states. Although all EMT subpopulations presented similar tumour-propagating cell capacity, they displayed differences in cellular plasticity, invasiveness and metastatic potential. Their transcriptional and epigenetic landscapes identify the underlying gene regulatory networks, transcription factors and signalling pathways that control these different EMT transition states. Finally, these tumour subpopulations are localized in different niches that differentially regulate EMT transition states.