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Immune cells identify and destroy tumors by recognizing cellular traits indicative of oncogenic transformation. In this study, we found that myocardin-related transcription factors (MRTFs), which promote migration and metastatic invasion, also sensitize cancer cells to the immune system. Melanoma and breast cancer cells with high MRTF expression were selectively eliminated by cytotoxic lymphocytes in mouse models of metastasis. This immunosurveillance phenotype was further enhanced by treatment with immune checkpoint blockade (ICB) antibodies. We also observed that high MRTF signaling in human melanoma is associated with ICB efficacy in patients. Using biophysical and functional assays, we showed that MRTF overexpression rigidified the filamentous actin cytoskeleton and that this mechanical change rendered mouse and human cancer cells more vulnerable to cytotoxic T lymphocytes and natural killer cells. Collectively, these results suggest that immunosurveillance has a mechanical dimension, which we call mechanosurveillance, that is particularly relevant for the targeting of metastatic disease.
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Linfocitos/inmunología , Neoplasias/inmunología , Citoesqueleto de Actina/inmunología , Actinas/inmunología , Animales , Comunicación Celular/inmunología , Línea Celular , Línea Celular Tumoral , Movimiento Celular/inmunología , Femenino , Células HEK293 , Humanos , Células Asesinas Naturales/inmunología , Células MCF-7 , Masculino , Ratones , Ratones Endogámicos C57BL , Transducción de Señal/inmunología , Factores de Transcripción/inmunologíaRESUMEN
The cell surface glycoprotein Trop-2 is commonly overexpressed in carcinomas and represents an exceptional antigen for targeted therapy. Here, we provide evidence that surface Trop-2 expression is functionally connected with an epithelial phenotype in breast and prostate cell lines and in patient tumor samples. We further show that Trop-2 expression is suppressed epigenetically or through the action of epithelial-to-mesenchymal transition transcription factors and that deregulation of Trop-2 expression is linked with cancer progression and poor patient prognosis. Moreover, our data suggest that the cancer plasticity-driven intratumoral heterogeneity in Trop-2 expression may significantly contribute to response and resistance to therapies targeting Trop-2-expressing cells.
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Antígenos de Neoplasias/metabolismo , Neoplasias de la Mama/patología , Carcinoma/patología , Moléculas de Adhesión Celular/metabolismo , Células Epiteliales/metabolismo , Neoplasias de la Próstata/patología , Animales , Antígenos CD/biosíntesis , Antígenos de Neoplasias/genética , Neoplasias de la Mama/mortalidad , Cadherinas/biosíntesis , Moléculas de Adhesión Celular/genética , Línea Celular Tumoral , Metilación de ADN/genética , Progresión de la Enfermedad , Transición Epitelial-Mesenquimal/fisiología , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Neoplasias de la Próstata/mortalidad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Background:The intratumoural heterogeneity, often driven by epithelial-to-mesenchymal transition (EMT), significantly contributes to chemoresistance and disease progression in adenocarcinomas. Methods:We introduced a high-throughput screening platform to identify surface antigens that associate with epithelialmesenchymal plasticity in well-defined pairs of epithelial cell lines and their mesenchymal counterparts. Using multicolour flow cytometry, we then analysed the expression of 10 most robustly changed antigens and identified a 10-molecule surface signature, in pan-cytokeratin-positive/EpCAM-positive and -negative fractions of dissociated breast tumours. Results:We found that surface CD9, CD29, CD49c, and integrin ß5 are lost in breast cancer cells that underwent EMT in vivo. The tetraspanin family member CD9 was concordantly downregulated both in vitro and in vivo and associated with epithelial phenotype and favourable prognosis. Conclusions:We propose that overall landscape of 10-molecule surface signature expression reflects the epithelialmesenchymal plasticity in breast cancer.
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Antígenos de Neoplasias/biosíntesis , Antígenos de Superficie/biosíntesis , Neoplasias de la Mama/genética , Neoplasias de la Mama/inmunología , Antígenos de Neoplasias/inmunología , Antígenos de Superficie/inmunología , Biomarcadores de Tumor , Neoplasias de la Mama/patología , Línea Celular Tumoral , Plasticidad de la Célula/inmunología , Reprogramación Celular/fisiología , Transición Epitelial-Mesenquimal/inmunología , Femenino , Citometría de Flujo , Ensayos Analíticos de Alto Rendimiento , Humanos , Metástasis de la Neoplasia , Tetraspanina 29/biosíntesis , Tetraspanina 29/inmunología , Transcripción GenéticaRESUMEN
Complex analysis of cellular responses after experimental treatment is important for screening, mechanistic understanding of treatment effects, and the identification of sensitive and resistant cell phenotypes. Modern multicolor flow cytometry has demonstrated its power for such analyses. Here, we introduce a multiparametric protocol for complex analysis of cytokinetics by the simultaneous detection of seven fluorescence parameters. This analysis includes the detection of two surface markers for immunophenotyping, analysis of proliferation based on the cell cycle and the measurement of incorporated nucleoside analogue 5-ethynyl-2'-deoxyuridine (EdU) in newly synthesized DNA, analysis of DNA damage using an anti-phospho-histone H2A.X (Ser139) antibody, and determination of cell death using a fixable viability probe and intracellular detection of caspase-3 activation. To demonstrate the applicability of this protocol for the analysis of heterogeneous and complex cell responses, we used different treatments and model cell lines. We demonstrated that this protocol has the potential to provide complex and simultaneous analysis of cytokinetics and analyze the heterogeneity of the response at the single-cell level. © 2017 International Society for Advancement of Cytometry.
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Apoptosis/fisiología , Proliferación Celular/fisiología , Daño del ADN/fisiología , Citometría de Flujo/métodos , Inmunofenotipificación/métodos , Línea Celular Tumoral , HumanosRESUMEN
The identification of fibroblasts and cancer-associated fibroblasts from human cancer tissue using surface markers is difficult, especially because the markers used currently are usually not expressed solely by fibroblasts, and the identification of fibroblast-specific surface molecules is still under investigation. It was aimed to compare three commercially available antibodies in the detection of different surface epitopes of fibroblasts (anti-fibroblast, fibroblast activation protein α, and fibroblast surface protein). The specificity of their expression, employing fibroblast cell lines and tumor-derived fibroblasts from breast and prostate tissues was investigated. Both the established fibroblast cell line HFF-1 and ex vivo primary fibroblasts isolated from breast and prostate cancer tissues expressed the tested surface markers to different degrees. Surprisingly, those markers were expressed also by permanent cell lines of epithelial origin, both benign and cancer-derived (breast-cell lines MCF 10A, HMLE and prostate-cell lines BPH-1, DU 145, and PC-3). The expression of fibroblast activation protein α increased on the surface of previously described models of epithelial cells undergoing epithelial-to-mesenchymal transition in response to treatment with TGF-ß1. To prove the co-expression of the fibroblast markers on cells of epithelial origin, we used freshly dissociated human prostate and breast cancer tissues. The results confirmed the co-expression of anti-fibroblast and fibroblast surface protein on CD31/CD45-negative/EpCAM-positive epithelial cells. In summary, our data support the findings that the tested fibroblast markers are not fibroblast specific and may be expressed also by cells of epithelial origin (e.g., cells undergoing EMT). Therefore, the expression of these markers should be interpreted with caution, and the combination of several epitopes for both positive (anti-fibroblast or fibroblast activation protein α) and negative (EpCAM) identification of fibroblasts from breast and prostate tumor tissues is advised. © 2017 International Society for Advancement of Cytometry.
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Biomarcadores/metabolismo , Transición Epitelial-Mesenquimal/fisiología , Fibroblastos/metabolismo , Gelatinasas/metabolismo , Proteínas de la Membrana/metabolismo , Serina Endopeptidasas/metabolismo , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Endopeptidasas , Molécula de Adhesión Celular Epitelial/metabolismo , Células Epiteliales/metabolismo , Femenino , Humanos , Antígenos Comunes de Leucocito/metabolismo , Masculino , Células PC-3 , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/metabolismo , Neoplasias de la Próstata/metabolismo , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
PURPOSE: The purpose of the study was to determine whether the GDF-15 is present in follicular fluid; to evaluate if there is a relation between follicular and serum levels of GDF-15 and fertility status of study subjects; and to test whether granulosa cells, oocytes, or both produce GDF-15. METHODS: This study used follicular fluid (FF, serum, and oocytes obtained under informed consent from women undergoing oocyte retrieval for in vitro fertilization. It also used ovaries from deceased preterm newborns. Collection of FF and blood at the time of oocyte retrieval, ELISA and western blot were performed to determine levels and forms of GDF-15. Concentrations of GDF-15 in FF and serum, its expression in ovarian tissue, and secretion from granulosa cells were analyzed. RESULTS: GDF-15 concentration in FF ranged from 35 to 572 ng/ml, as determined by ELISA. Western blot analysis revealed the GDF-15 pro-dimer only in FF. Both normal healthy and cancerous granulosa cells secreted GDF-15 into culture media. Primary oocytes displayed cytoplasmic GDF-15 positivity in immunostained newborn ovaries, and its expression was also observed in fully grown human oocytes. CONCLUSIONS: To the best of our knowledge, this is the first documentation of cytokine GDF-15 presence in follicular fluid. Its concentration was not associated with donor/patient fertility status. Our data also show that GDF-15 is expressed and inducible in both normal healthy and cancerous granulosa cells, as well as in oocytes.
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Diferenciación Celular/genética , Líquido Folicular/metabolismo , Células de la Granulosa/metabolismo , Factor 15 de Diferenciación de Crecimiento/genética , Adulto , Femenino , Fertilización In Vitro , Regulación del Desarrollo de la Expresión Génica , Factor 15 de Diferenciación de Crecimiento/aislamiento & purificación , Humanos , Recuperación del Oocito , Oocitos/metabolismoRESUMEN
The leptomeninges, the cerebrospinal-fluid-filled tissues surrounding the central nervous system, play host to various pathologies including infection, neuroinflammation and malignancy. Spread of systemic cancer into this space, termed leptomeningeal metastasis, occurs in 5-10% of patients with solid tumours and portends a bleak clinical prognosis. Previous, predominantly descriptive, clinical studies have provided few insights. Recent development of preclinical leptomeningeal metastasis models, alongside genomic, transcriptomic and proteomic sequencing efforts, has provided groundwork for mechanistic understanding and identification of long-needed therapeutic targets. Although previously understood as an anatomically isolated compartment, the leptomeninges are increasingly appreciated as a major conduit of communication between the systemic circulation and the central nervous system. Despite the unique nature of the leptomeningeal microenvironment, the general principles of metastasis hold true: cells metastasizing to the leptomeninges must gain access to the new environment, survive within the space and evade the immune system. The study of leptomeningeal metastasis has the potential to uncover novel site-specific metastatic principles and illuminate the physiology of the leptomeningeal space. In this Review, we provide a biology-focused overview of how metastatic cells reach the leptomeninges, thrive in this nutritionally sparse environment and evade the detection of the omnipresent immune system.
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Neoplasias Meníngeas , Microambiente Tumoral , Humanos , Neoplasias Meníngeas/secundario , AnimalesRESUMEN
A key challenge of analyzing data from high-resolution spatial profiling technologies is to suitably represent the features of cellular neighborhoods or niches. Here we introduce the covariance environment (COVET), a representation that leverages the gene-gene covariate structure across cells in the niche to capture the multivariate nature of cellular interactions within it. We define a principled optimal transport-based distance metric between COVET niches that scales to millions of cells. Using COVET to encode spatial context, we developed environmental variational inference (ENVI), a conditional variational autoencoder that jointly embeds spatial and single-cell RNA sequencing data into a latent space. ENVI includes two decoders: one to impute gene expression across the spatial modality and a second to project spatial information onto single-cell data. ENVI can confer spatial context to genomics data from single dissociated cells and outperforms alternatives for imputing gene expression on diverse spatial datasets.
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Leptomeningeal metastases are increasingly becoming recognized as a treatable, yet generally incurable, complication of advanced cancer. As modern cancer therapeutics have prolonged the lives of patients with metastatic cancer, specifically in patients with parenchymal brain metastases, treatment options and clinical research protocols for patients with leptomeningeal metastases from solid tumors have similarly evolved to improve survival within specific populations. Recent expansion in clinical investigation, early diagnosis, and drug development have given rise to new unanswered questions. These include leptomeningeal metastasis biology and preferred animal modeling, epidemiology in the modern cancer population, ensuring validation and accessibility of newer leptomeningeal metastasis diagnostics, best clinical practices with multi-modality treatment options, clinical trial design and standardization of response assessments, and avenues worthy of further research. An international group of multi-disciplinary experts in the research and management of leptomeningeal metastases, supported by the Society for Neuro-Oncology and American Society of Clinical Oncology, were assembled to reach a consensus opinion on these pressing topics and provide a roadmap for future directions. Our hope is that these recommendations will accelerate collaboration and progress in the field of leptomeningeal metastases and serve as a platform for further discussion and patient advocacy.
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The distribution of fluorescence signals measured with flow cytometry can be influenced by several factors, including qualitative and quantitative properties of the used fluorochromes, optical properties of the detection system, as well as the variability within the analyzed cell population itself. Most of the single cell samples prepared from in vitrocultures or clinical specimens contain a variable cell cycle component. Cell cycle, together with changes in the cell size, are two of the factors that alter the functional properties of analyzed cells and thus affect the interpretation of obtained results. Here, we describe the association between cell cycle status and cell size, and the variability in the distribution of fluorescence intensity as determined with flow cytometry, at population scale. We show that variability in the distribution of background and specific fluorescence signals is related to the cell cycle state of the selected population, with the 10% low fluorescence signal fraction enriched mainly in cells in their G0/G1 cell cycle phase, and the 10% high fraction containing cells mostly in the G2/M phase. Therefore we advise using caution and additional experimental validation when comparing populations defined by fractions at both ends of fluorescence signal distribution to avoid biases caused by the effect of cell cycle and cell size.
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Fase G2 , Citometría de Flujo/métodos , División Celular , Ciclo Celular/fisiología , Tamaño de la CélulaRESUMEN
Triple-negative breast cancer (TNBC) is an aggressive and complex subtype of breast cancer that lacks targeted therapy. TNBC manifests characteristic, extensive intratumoral heterogeneity that promotes disease progression and influences drug response. Single-cell techniques in combination with next-generation computation provide an unprecedented opportunity to identify molecular events with therapeutic potential. Here, we describe the generation of a comprehensive mass cytometry panel for multiparametric detection of 23 phenotypic markers and 13 signaling molecules. This single-cell proteomic approach allowed us to explore the landscape of TNBC heterogeneity, with particular emphasis on the tumor microenvironment. We prospectively profiled freshly resected tumors from 26 TNBC patients. These tumors contained phenotypically distinct subpopulations of cancer and stromal cells that were associated with the patient's clinical status at the time of surgery. We further classified the epithelial-mesenchymal plasticity of tumor cells, and molecularly defined phenotypically diverse populations of tumor-associated stroma. Furthermore, in a retrospective tissue-microarray TNBC cohort, we showed that the level of CD97 at the time of surgery has prognostic potential.
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Neoplasias de la Mama Triple Negativas , Humanos , Neoplasias de la Mama Triple Negativas/metabolismo , Proteómica , Estudios Retrospectivos , Transducción de Señal , Células del Estroma/metabolismo , Línea Celular Tumoral , Microambiente TumoralRESUMEN
Metastasis to the cerebrospinal fluid (CSF)-filled leptomeninges, or leptomeningeal metastasis (LM), represents a fatal complication of cancer. Proteomic and transcriptomic analyses of human CSF reveal a substantial inflammatory infiltrate in LM. We find the solute and immune composition of CSF in the setting of LM changes dramatically, with notable enrichment in IFN-γ signaling. To investigate the mechanistic relationships between immune cell signaling and cancer cells within the leptomeninges, we developed syngeneic lung, breast, and melanoma LM mouse models. Here we show that transgenic host mice, lacking IFN-γ or its receptor, fail to control LM growth. Overexpression of Ifng through a targeted AAV system controls cancer cell growth independent of adaptive immunity. Instead, leptomeningeal IFN-γ actively recruits and activates peripheral myeloid cells, generating a diverse spectrum of dendritic cell subsets. These migratory, CCR7+ dendritic cells orchestrate the influx, proliferation, and cytotoxic action of natural killer cells to control cancer cell growth in the leptomeninges. This work uncovers leptomeningeal-specific IFN-γ signaling and suggests a novel immune-therapeutic approach against tumors within this space.
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Multicolor flow cytometry allows for analysis of tens of cellular parameters in millions of cells at a single-cell resolution within minutes. The lack of technologies that would facilitate feasible and relatively cheap profiling of such a number of cells with an antibody-based approach led us to the development of a high-throughput cytometry-based platform for surface profiling. We coupled the fluorescent cell barcoding with preexisting, commercially available screening tools to analyze cell surface fingerprint at a large scale. This powerful approach will help to identify novel biomarkers and druggable targets and facilitate the discovery of new concepts in immunology, oncology, and developmental biology.
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Antígenos de Superficie , Investigación , Biomarcadores/análisis , Citometría de Flujo , Colorantes FluorescentesRESUMEN
BACKGROUND: Leptomeningeal metastasis (LM), or spread of cancer cells into the cerebrospinal fluid (CSF), is characterized by a rapid onset of debilitating neurological symptoms and markedly bleak prognosis. The lack of reproducible in vitro and in vivo models has prevented the development of novel, LM-specific therapies. Although LM allows for longitudinal sampling of floating cancer cells with a spinal tap, attempts to culture patient-derived leptomeningeal cancer cells have not been successful. AIM: We, therefore, employ leptomeningeal derivatives of human breast and lung cancer cell lines that reproduce both floating and adherent phenotypes of human LM in vivo and in vitro. METHODS AND RESULTS: We introduce a trypsin/EDTA-based fractionation method to reliably separate the two cell subsets and demonstrate that in vitro cultured floating cells have decreased proliferation rate, lower ATP content, and are enriched in distinct metabolic signatures. Long-term fractionation and transcriptomic analysis suggest high degree plasticity between the two phenotypes in vitro. Floating cells colonize mouse leptomeninges more rapidly and associate with shortened survival. In addition, patients harboring LM diagnosed with CSF disease alone succumbed to the disease earlier than patients with adherent (MRI positive) disease. CONCLUSION: Together, these data support mechanistic evidence of a metabolic adaptation that allows cancer cells to thrive in their natural environment but leads to death in vitro.
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Neoplasias Pulmonares , Carcinomatosis Meníngea , Animales , Biomarcadores de Tumor , Línea Celular Tumoral , Humanos , Neoplasias Pulmonares/patología , Carcinomatosis Meníngea/líquido cefalorraquídeo , Carcinomatosis Meníngea/secundario , Ratones , FenotipoRESUMEN
BACKGROUND: The progenitors to lung airway epithelium that are capable of long-term propagation may represent an attractive source of cells for cell-based therapies, disease modeling, toxicity testing, and others. Principally, there are two main options for obtaining lung epithelial progenitors: (i) direct isolation of endogenous progenitors from human lungs and (ii) in vitro differentiation from some other cell type. The prime candidates for the second approach are pluripotent stem cells, which may provide autologous and/or allogeneic cell resource in clinically relevant quality and quantity. METHODS: By exploiting the differentiation potential of human embryonic stem cells (hESC), here we derived expandable lung epithelium (ELEP) and established culture conditions for their long-term propagation (more than 6 months) in a monolayer culture without a need of 3D culture conditions and/or cell sorting steps, which minimizes potential variability of the outcome. RESULTS: These hESC-derived ELEP express NK2 Homeobox 1 (NKX2.1), a marker of early lung epithelial lineage, display properties of cells in early stages of surfactant production and are able to differentiate to cells exhibitting molecular and morphological characteristics of both respiratory epithelium of airway and alveolar regions. CONCLUSION: Expandable lung epithelium thus offer a stable, convenient, easily scalable and high-yielding cell source for applications in biomedicine.
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Células Madre Embrionarias Humanas , Diferenciación Celular , Epitelio , Humanos , Pulmón/metabolismo , Tensoactivos/metabolismoRESUMEN
Triple-negative breast cancer (TNBC) is a subtype of breast carcinoma known for its unusually aggressive behavior and poor clinical outcome. Besides the lack of molecular targets for therapy and profound intratumoral heterogeneity, the relatively quick overt metastatic spread remains a major obstacle in effective clinical management. The metastatic colonization of distant sites by primary tumor cells is affected by the microenvironment, epigenetic state of particular subclones, and numerous other factors. One of the most prominent processes contributing to the intratumoral heterogeneity is an epithelial-mesenchymal transition (EMT), an evolutionarily conserved developmental program frequently hijacked by tumor cells, strengthening their motile and invasive features. In response to various intrinsic and extrinsic stimuli, malignant cells can revert the EMT state through the mesenchymal-epithelial transition (MET), a process that is believed to be critical for the establishment of macrometastasis at secondary sites. Notably, cancer cells rarely undergo complete EMT and rather exist in a continuum of E/M intermediate states, preserving high levels of plasticity, as demonstrated in primary tumors and, ultimately, in circulating tumor cells, representing a simplified element of the metastatic cascade. In this review, we focus on cellular drivers underlying EMT/MET phenotypic plasticity and its detrimental consequences in the context of TNBC cancer.
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Meninges, or the membranous coverings of the brain and spinal cord, play host to dozens of morbid pathologies. In this study we provide a method to isolate the leptomeningeal cell layer, identify leptomeninges in histologic slides, and maintain leptomeningeal fibroblasts in in vitro culture. Using an array of transcriptomic, histological, and cytometric analyses, we identified ICAM1 and SLC38A2 as two novel markers of leptomeningeal cells in vivo and in vitro. Our results confirm the fibroblastoid nature of leptomeningeal cells and their ability to form a sheet-like layer that covers the brain and spine parenchyma. These findings will enable researchers in central nervous system barriers to describe leptomeningeal cell functions in health and disease.
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Fibroblastos/citología , Meninges/citología , Adulto , Anciano , Sistema de Transporte de Aminoácidos A/análisis , Sistema de Transporte de Aminoácidos A/biosíntesis , Sistema de Transporte de Aminoácidos A/genética , Animales , Secuencia de Bases , Biomarcadores , Separación Celular , Células Cultivadas , Preescolar , Femenino , Fibroblastos/metabolismo , Humanos , Molécula 1 de Adhesión Intercelular/análisis , Molécula 1 de Adhesión Intercelular/biosíntesis , Molécula 1 de Adhesión Intercelular/genética , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Microdisección , Persona de Mediana Edad , Cultivo Primario de Células , Coloración y Etiquetado/métodos , TranscriptomaRESUMEN
SARS-CoV-2 infection induces a wide spectrum of neurologic dysfunction that emerges weeks after the acute respiratory infection. To better understand this pathology, we prospectively analyzed of a cohort of cancer patients with neurologic manifestations of COVID-19, including a targeted proteomics analysis of the cerebrospinal fluid. We find that cancer patients with neurologic sequelae of COVID-19 harbor leptomeningeal inflammatory cytokines in the absence of viral neuroinvasion. The majority of these inflammatory mediators are driven by type II interferon and are known to induce neuronal injury in other disease states. In these patients, levels of matrix metalloproteinase-10 within the spinal fluid correlate with the degree of neurologic dysfunction. Furthermore, this neuroinflammatory process persists weeks after convalescence from acute respiratory infection. These prolonged neurologic sequelae following systemic cytokine release syndrome lead to long-term neurocognitive dysfunction. Our findings suggest a role for anti-inflammatory treatment(s) in the management of neurologic complications of COVID-19 infection.
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Encefalopatías/etiología , COVID-19/complicaciones , Mediadores de Inflamación/líquido cefalorraquídeo , Neoplasias/virología , Enzima Convertidora de Angiotensina 2/metabolismo , Encéfalo/diagnóstico por imagen , Encéfalo/patología , COVID-19/epidemiología , Proteínas del Líquido Cefalorraquídeo/análisis , Comorbilidad , Citocinas/líquido cefalorraquídeo , Humanos , Neoplasias/complicaciones , Neoplasias/epidemiología , NeuroimagenRESUMEN
Medulloblastoma (MB) is a malignant pediatric brain tumor arising in the cerebellum. Although abnormal GABAergic receptor activation has been described in MB, studies have not yet elucidated the contribution of receptor-independent GABA metabolism to MB pathogenesis. We find primary MB tumors globally display decreased expression of GABA transaminase (ABAT), the protein responsible for GABA metabolism, compared with normal cerebellum. However, less aggressive WNT and SHH subtypes express higher ABAT levels compared with metastatic G3 and G4 tumors. We show that elevated ABAT expression results in increased GABA catabolism, decreased tumor cell proliferation, and induction of metabolic and histone characteristics mirroring GABAergic neurons. Our studies suggest ABAT expression fluctuates depending on metabolite changes in the tumor microenvironment, with nutrient-poor conditions upregulating ABAT expression. We find metastatic MB cells require ABAT to maintain viability in the metabolite-scarce cerebrospinal fluid by using GABA as an energy source substitute, thereby facilitating leptomeningeal metastasis formation.
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4-Aminobutirato Transaminasa/metabolismo , Neoplasias Cerebelosas/líquido cefalorraquídeo , Neoplasias Cerebelosas/enzimología , Meduloblastoma/líquido cefalorraquídeo , Meduloblastoma/enzimología , Meninges/patología , Microambiente Tumoral , Acetilación , Animales , Diferenciación Celular , Línea Celular Tumoral , Proliferación Celular , Supervivencia Celular , Femenino , Histona Desacetilasas/metabolismo , Histonas/metabolismo , Lisina/metabolismo , Neoplasias Meníngeas/secundario , Ratones Desnudos , Mitocondrias/metabolismo , Neuronas/metabolismo , Fosforilación Oxidativa , Fenotipo , Ratas , Ácido gamma-Aminobutírico/metabolismoRESUMEN
Trophoblast cell surface antigen 2 (Trop2) is a widely expressed glycoprotein and an epithelial cell adhesion molecule (EpCAM) family member. Although initially identified as a transmembrane protein, other subcellular localizations and processed forms were described. Its congenital mutations cause a gelatinous drop-like corneal dystrophy, a disease characterized by loss of barrier function in corneal epithelial cells. Trop2 is considered a stem cell marker and its expression associates with regenerative capacity in various tissues. Trop2 overexpression was described in tumors of different origins; however, functional studies revealed both oncogenic and tumor suppressor roles. Nevertheless, therapeutic potential of Trop2 was recognized and clinical studies with drug-antibody conjugates have been initiated in various cancer types. One of these agents, sacituzumab govitecan, has been recently granted an accelerated approval for therapy of metastatic triple-negative breast cancer. In this article, we review the current knowledge about the yet controversial function of Trop2 in homeostasis and pathology.