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Treatment of melanomas with targeted and immunotherapies has proven effective, but resistance to both treatments is a common outcome leaving a high proportion of patients without effective alternative treatment options. Replication stress is a common feature of melanomas, and this is effectively targeted using a combination of checkpoint kinase 1 (CHK1) inhibitor and low-dose hydroxyurea (LDHU). This combination also promotes inflammatory and anti-tumour immune responses in vivo. Melanoma cell lines resistant to BRAF inhibitor (BRAFi) or immune checkpoint inhibitors (ICI) retain their sensitivity to CHK1i + LDHU, with sensitivity similar to that of parental tumours. In vivo, BRAFi-resistant and BRAFi-sensitive parental tumours produce an identical immune response with treatment.
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Melanoma , Humanos , Melanoma/patología , Hidroxiurea/farmacología , Hidroxiurea/uso terapéutico , Proteínas Proto-Oncogénicas B-raf , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/uso terapéutico , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Resistencia a Antineoplásicos , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Línea Celular TumoralRESUMEN
BACKGROUND: Vietnam's economy and intellectual standards have witnessed significant development, improving conditions for residents to acquire novel mHealth applications. Additionally, the outbreak of the COVID-19 pandemic has influenced Vietnamese awareness of healthcare; however, previous studies have only been clinician-centered rather than customer-centered. METHODS: This study addresses this literature gap by interviewing 50 Vietnamese participants grouped by age, namely Generation X, Generation Y, and Generation Z, and health conditions, namely whether participants or family members have chronic illness. The study utilized semi-structured and in-depth interviews to collect the data and used thematic analysis to analyze the data under the unified theory of acceptance and use of technology framework. RESULTS: Most participants were willing to adopt this technology and demanded a convenient and user-friendly one-stop-shop solution, endorsements from credible and authoritative sources, and professional customer services. However, each group also had distinctive demands and behaviors. CONCLUSION: This study contributes theoretically by providing context-rich demand for Vietnamese customers across three generations and healthcare conditions during the COVID-19 pandemic and comparing their behavior with pre-COVID literature. While this research provides helpful information for potential app developers, this study also suggests that mHealth developers and policymakers should pay more attention to the differences in the demand of age groups and health conditions.
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The ability to utilize preclinical models to predict the clinical toxicity of chimeric antigen receptor (CAR) T cells in solid tumors is tenuous, thereby necessitating the development and evaluation of gated systems. Here we found that murine GD2 CAR-T cells, specific for the tumor-associated antigen GD2, induce fatal neurotoxicity in a costimulatory domain-dependent manner. Meanwhile, human B7H3 CAR-T cells exhibit efficacy in preclinical models of neuroblastoma. Seeking a better CAR, we generated a SynNotch gated CAR-T, GD2-B7H3, recognizing GD2 as the gate and B7H3 as the target. GD2-B7H3 CAR-T cells control the growth of neuroblastoma in vitro and in metastatic xenograft mouse models, with high specificity and efficacy. These improvements come partly from the better metabolic fitness of GD2-B7H3 CAR-T cells, as evidenced by their naïve T-like post-cytotoxicity oxidative metabolism and lower exhaustion profile.
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Gangliósidos/inmunología , Inmunoterapia Adoptiva/métodos , Neuroblastoma/terapia , Receptores de Antígenos de Linfocitos T/inmunología , Receptores Quiméricos de Antígenos/inmunología , Ensayos Antitumor por Modelo de Xenoinjerto/métodos , Animales , Línea Celular Tumoral , Supervivencia Celular/inmunología , Citotoxicidad Inmunológica/inmunología , Gangliósidos/metabolismo , Humanos , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Metástasis de la Neoplasia , Neuroblastoma/inmunología , Neuroblastoma/patología , Receptores de Antígenos de Linfocitos T/metabolismo , Receptores Quiméricos de Antígenos/metabolismo , Carga Tumoral/inmunologíaRESUMEN
Immune checkpoint therapy has resulted in minimal clinical response in many pediatric cancers. We sought to understand the influence of immune checkpoint inhibition using anti-PD-1 and anti-CTLA-4 antibodies individually, in combination, and after chemotherapy on immune responses in minimal and established murine neuroblastoma models. We also sought to understand the role of the tumor microenvironment (TME) and PD-L1 expression and their alteration post-chemotherapy in our models and human tissues. PD-L1 expression was enriched in human tumor-associated macrophages and up-regulated after chemotherapy. In a murine minimal disease model, single and dual immune checkpoint blockade promoted tumor rejection, improved survival, and established immune memory with long-term anti-tumor immunity against re-challenge. In an established tumor model, only dual immune checkpoint blockade showed efficacy. Interestingly, dual immune checkpoint therapy distinctly influenced adaptive and innate immune responses, with significant increase in CD8+CD28+PD-1+ T cells and inflammatory macrophages (CD11bhiCD11c-F4/80+Ly6Chi) in tumor-draining lymph nodes. Adding chemotherapy before immunotherapy provided significant survival benefit for mice with established tumors receiving anti-PD-1 or dual immune checkpoint blockade. Our findings demonstrate anti-PD-1 and anti-CTLA-4 therapy induces a novel subset of effector T cells, and support administration of induction chemotherapy immediately prior to immune checkpoint blockade in children with high-risk neuroblastoma.
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Neuroblastoma , Receptor de Muerte Celular Programada 1 , Animales , Antígenos CD28 , Linfocitos T CD8-positivos , Humanos , Inhibidores de Puntos de Control Inmunológico , Ratones , Neuroblastoma/tratamiento farmacológico , Linfocitos T , Microambiente TumoralRESUMEN
INTRODUCTION: The infant gut microbiome is thought to play a key role in developing metabolic and immunologic pathways. Antibiotics have been shown to disrupt the human microbiome, but the impact they have on infants during this key window of development remains poorly understood. Through this study, we further characterize the effect antibiotics have on the gut microbiome of infants by looking at metagenomic sequencing data over time. MATERIALS AND METHODS: Stool samples were collected on infants from a large tertiary care neonatal intensive care unit. After DNA extraction, metagenomics libraries were generated and sequenced. Taxonomic and functional analyses were then performed. Further directed specimen sequencing for fungal species was also performed. RESULTS: A total of 51 stool samples from 25 infants were analyzed: seven infants were on antibiotics during at least one of their collection time points. Antibiotics given at birth altered the microbiome (PERMANOVA R2 = 0.044, p = .002) but later courses did not (R2 = 0.023, p = .114). Longitudinal samples collected while off antibiotics were more similar than those collected during a transition on or off antibiotics (mean Bray-Curtis distance 0.29 vs. 0.63, Wilcoxon p = .06). Functional analysis revealed four microbial pathways that were disrupted by antibiotics given at-birth (p < .1, folate synthesis, glycerolipid metabolism, fatty acid biosynthesis, and glycolysis). No functional changes associated with current antibiotic use were identified. In a limited sample set, we saw little evidence of fungal involvement in the overall infant microbiome. CONCLUSION: Through this study, we have further characterized the role antibiotics have in the development of the infant microbiome. Antibiotics given at birth were associated with alterations in the microbiome and had significant impact on the functional pathways involved in folate synthesis and multiple metabolic pathways. Later courses of antibiotics led to stochastic dysbiosis and a significant decrease in Escherichia coli. Further characterization of the infant mycobiome is still needed.
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Microbioma Gastrointestinal , Antibacterianos , Disbiosis , Heces , Humanos , Lactante , Recién Nacido , Unidades de Cuidado Intensivo NeonatalRESUMEN
Molecular and functional characterization of alveolar epithelial type I (AT1) cells has been challenging due to difficulty in isolating sufficient numbers of viable cells. Here we performed single-cell RNA-sequencing (scRNA-seq) of tdTomato+ cells from lungs of AT1 cell-specific Aqp5-Cre-IRES-DsRed (ACID);R26tdTomato reporter mice. Following enzymatic digestion, CD31-CD45-E-cadherin+tdTomato+ cells were subjected to fluorescence-activated cell sorting (FACS) followed by scRNA-seq. Cell identity was confirmed by immunofluorescence using cell type-specific antibodies. After quality control, 92 cells were analyzed. Most cells expressed 'conventional' AT1 cell markers (Aqp5, Pdpn, Hopx, Ager), with heterogeneous expression within this population. The remaining cells expressed AT2, club, basal or ciliated cell markers. Integration with public datasets identified three robust AT1 cell- and lung-enriched genes, Ager, Rtkn2 and Gprc5a, that were conserved across species. GPRC5A co-localized with HOPX and was not expressed in AT2 or airway cells in mouse, rat and human lung. GPRC5A co-localized with AQP5 but not pro-SPC or CC10 in mouse lung epithelial cell cytospins. We enriched mouse AT1 cells to perform molecular phenotyping using scRNA-seq. Further characterization of putative AT1 cell-enriched genes revealed GPRC5A as a conserved AT1 cell surface marker that may be useful for AT1 cell isolation.
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Células Epiteliales Alveolares/metabolismo , Acuaporina 5/metabolismo , Membrana Celular/metabolismo , Pulmón/citología , Receptores Acoplados a Proteínas G/metabolismo , Análisis de Secuencia de ARN , Análisis de la Célula Individual , Animales , Biomarcadores/metabolismo , Separación Celular , Humanos , Ratones Transgénicos , Ratas , Reproducibilidad de los ResultadosRESUMEN
INTRODUCTION: Medulloblastoma is a malignant embryonal tumor of the cerebellum that occurs predominantly in children. To find germline genetic variants associated with medulloblastoma risk, we conducted a genome-wide association study (GWAS) including 244 medulloblastoma cases and 247 control subjects from Sweden and Denmark. METHODS: Genotyping was performed using Illumina BeadChips, and untyped variants were imputed using IMPUTE2. RESULTS: Fifty-nine variants in 11 loci were associated with increased medulloblastoma risk (p < 1 × 10-5), but none were statistically significant after adjusting for multiple testing (p < 5 × 10-8). Thirteen of these variants were genotyped, whereas 46 were imputed. Genotyped variants were further investigated in a validation study comprising 249 medulloblastoma cases and 629 control subjects. In the validation study, rs78021424 (18p11.23, PTPRM) was associated with medulloblastoma risk with OR in the same direction as in the discovery cohort (ORT = 1.59, pvalidation = 0.02). We also selected seven medulloblastoma predisposition genes for investigation using a candidate gene approach: APC, BRCA2, PALB2, PTCH1, SUFU, TP53, and GPR161. The strongest evidence for association was found for rs201458864 (PALB2, ORT = 3.76, p = 3.2 × 10-4) and rs79036813 (PTCH1, ORA = 0.42, p = 2.6 × 10-3). CONCLUSION: The results of this study, including a novel potential medulloblastoma risk loci at 18p11.23, are suggestive but need further validation in independent cohorts.
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Biomarcadores de Tumor/genética , Neoplasias Cerebelosas/genética , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Meduloblastoma/genética , Polimorfismo de Nucleótido Simple , Estudios de Casos y Controles , Neoplasias Cerebelosas/patología , Estudios de Cohortes , Genotipo , Humanos , Meduloblastoma/patología , PronósticoRESUMEN
PURPOSE: Irradiation-avoiding strategies have been used with relative success in the treatment of infants and young children with medulloblastoma. While advances in cancer genomics have significantly improved our understanding of the tumor biology of medulloblastoma allowing for improved prognostication and risk-stratification, the molecular subgroup-specific outcomes of infants and young children with medulloblastoma treated with irradiation-avoiding strategies remains unknown. METHODS: Molecular and clinical features of children with medulloblastoma treated with irradiation-avoiding strategies at Children's Hospital Los Angeles were analyzed. Molecular subgrouping of these patients was determined using a 31-gene TaqMan Low Density Array signature. Survival analyses were conducted based on 3 molecular subgroups (SHH, Group 3, and Group 4). RESULTS: Twenty-eight patients with medulloblastoma received irradiation-sparing regimens and were included in this analysis. Patients were divided into SHH (n = 16), Group 3 (n = 3) and Group 4 subgroups (n = 9). Subgroup specific 5-year progression-free and overall survival was 81.2% (95% CI 52.5-93.5) and 93.7% (95% CI 63.2-99.1) for SHH, 0% and 0% for Group 3 and 0% and 44.4% (95% CI 13.6-71.9) for Group 4. CONCLUSION: The majority of young children with SHH-subgroup medulloblastoma can be treated effectively with irradiation-sparing regimens. Our results support the use of chemotherapy-only strategies for upfront treatment of young children with SHH medulloblastoma, while demonstrating the urgent need for intensification/augmentation of treatment for patients with group 3/4 medulloblastoma.
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Neoplasias Cerebelosas/diagnóstico , Neoplasias Cerebelosas/radioterapia , Meduloblastoma/diagnóstico , Meduloblastoma/cirugía , Neoplasias Cerebelosas/genética , Niño , Preescolar , Humanos , Lactante , Meduloblastoma/genética , Patología Molecular , Pronóstico , Supervivencia sin ProgresiónRESUMEN
BACKGROUND: Recent advances in sequencing technologies and bioinformatics tools have allowed for large-scale microbiome studies that are rapidly advancing medical research. However, small changes in technique or analysis can significantly alter the results and lead to conflicting findings. Quantifying the technical versus biological variation expected in targeted 16S rRNA gene sequencing studies and how this variation changes with input biomass is critical to guide meaningful interpretation of the current literature and plan future research. RESULTS: Data were compiled from 469 sequencing libraries across 19 separate targeted 16S rRNA gene sequencing runs over a 2.5-year time period. Following removal of contaminant sequences identified from negative controls, 244 samples retained sufficient reads for further analysis. Coefficients of variation for intra- and inter-assay variation from repeated measurements of a bacterial mock community ranged from 8.7 to 37.6% (intra) and 15.6 to 80.5% (inter) for all but one genus of bacteria whose relative abundance was greater than 1%. Intra- versus inter-assay Bray-Curtis pairwise distances for a single stool sample were 0.11 versus 0.31, whereas intra-assay variation from repeat stool samples from the same donor was greater at 0.38 (Wilcoxon p = 0.001). A dilution series of the bacterial mock community was used to assess the effect of input biomass on variability. Pairwise distances increased with more dilute samples, and estimates of relative abundance became unreliable below approximately 100 copies of the 16S rRNA gene per microliter. Using this data, we created a prediction model to estimate the expected variation in microbiome measurements for given input biomass and relative abundance values. CONCLUSIONS: Well-controlled microbiome studies are sufficiently robust to capture small biological effects and can achieve levels of variability consistent with clinical assays. Relative abundance is negatively associated with measures of variability and has a stronger effect on variability than does absolute biomass, suggesting that it is feasible to detect differences in bacterial populations in very low-biomass samples. Further, by quantifying the effect of biomass and relative abundance on compositional variability, we developed a tool for defining the expected variance in a given microbiome study.
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Bacterias/aislamiento & purificación , Microbioma Gastrointestinal , ARN Ribosómico 16S/genética , Bacterias/clasificación , Bacterias/genética , Bacterias/crecimiento & desarrollo , Biomasa , ADN Bacteriano/genética , Estudios de Evaluación como Asunto , Heces/microbiología , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , FilogeniaRESUMEN
Tumor-associated macrophages (TAMs) are strongly associated with poor survival in neuroblastomas that lack MYCN amplification. To study TAM action in neuroblastomas, we used a novel murine model of spontaneous neuroblastoma lacking MYCN amplification, and observed recruitment and polarization of TAMs, which in turn enhanced neuroblastoma proliferation and growth. In both murine and human neuroblastoma cells, we found that TAMs increased STAT3 activation in neuroblastoma cells and transcriptionally up-regulated the MYC oncogene. Analysis of human neuroblastoma tumor specimens revealed that MYC up-regulation correlates with markers of TAM infiltration. In an IL6ko neuroblastoma model, the absence of IL-6 protein had no effect on tumor development and prevented neither STAT3 activation nor MYC up-regulation. In contrast, inhibition of JAK-STAT activation using AZD1480 or the clinically admissible inhibitor ruxolitinib significantly reduced TAM-mediated growth of neuroblastomas implanted subcutaneously in NOD scid gamma mice. Our results point to a unique mechanism in which TAMs promote tumor cells that lack amplification of an oncogene common to the malignancy by up-regulating transcriptional expression of a distinct oncogene from the same gene family, and underscore the role of IL-6-independent activation of STAT3 in this mechanism. Amplification of MYCN or constitutive up-regulation of MYC protein is observed in approximately half of high-risk tumors; our findings indicate a novel role of TAMs as inducers of MYC expression in neuroblastomas lacking independent oncogene activation.
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The employment of a purpose-made capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (C4D) as a simple and cost-effective solution for clinical screening of paraquat in plasma samples for early-stage diagnosis of acute herbicide poisoning is reported. Paraquat was determined using an electrolyte composed of 10mM histidine adjusted to pH 4 with acetic acid. A detection limit of 0.5mg/L was achieved. Good agreement between results from CE-C4D and the confirmation method (HPLC-UV) was obtained, with relative errors for the two pairs of data better than 20% for 31 samples taken from paraquat-intoxicated patients. The results were used by medical doctors for identification and prognosis of acute paraquat poisoning cases. The objective of the work is the deployment of the developed approach in rural areas in Vietnam as a low-cost solution to reduce the mortality rate due to accidental or suicidal ingestion of paraquat.
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Electroforesis Capilar/métodos , Paraquat/sangre , Intoxicación , Conductividad Eléctrica , Hemoperfusión , Humanos , Límite de Detección , Paraquat/envenenamiento , Intoxicación/sangre , Intoxicación/diagnóstico , Intoxicación/terapia , Reproducibilidad de los Resultados , VietnamRESUMEN
BACKGROUND: Medulloblastomas in children can be categorized into 4 molecular subgroups with differing clinical characteristics, such that subgroup determination aids in prognostication and risk-adaptive treatment strategies. Magnetic resonance spectroscopy (MRS) is a widely available, noninvasive tool that is used to determine the metabolic characteristics of tumors and provide diagnostic information without the need for tumor tissue. In this study, we investigated the hypothesis that metabolite concentrations measured by MRS would differ between molecular subgroups of medulloblastoma and allow accurate subgroup determination. METHODS: MRS was used to measure metabolites in medulloblastomas across molecular subgroups (SHH = 12, Groups 3/4 = 17, WNT = 1). Levels of 14 metabolites were analyzed to determine those that were the most discriminant for medulloblastoma subgroups in order to construct a multivariable classifier for distinguishing between combined Group 3/4 and SHH tumors. RESULTS: Medulloblastomas across molecular subgroups revealed distinct spectral features. Group 3 and Group 4 tumors demonstrated metabolic profiles with readily detectable taurine, lower levels of lipids, and high levels of creatine. SHH tumors showed prominent choline and lipid with low levels of creatine and little or no evidence of taurine. A 5-metabolite subgroup classifier inclusive of creatine, myo-inositol, taurine, aspartate, and lipid 13a was developed that could discriminate between Group 3/4 and SHH medulloblastomas with excellent accuracy (cross-validated area under the curve [AUC] = 0.88). CONCLUSIONS: The data show that medulloblastomas of Group 3/4 differ metabolically as measured using MRS when compared with SHH molecular subgroups. MRS is a useful and accurate tool to determine medulloblastoma molecular subgroups.
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Neoplasias Cerebelosas/diagnóstico , Neoplasias Cerebelosas/patología , Espectroscopía de Resonancia Magnética , Meduloblastoma/diagnóstico , Meduloblastoma/patología , Biomarcadores de Tumor/metabolismo , Neoplasias Cerebelosas/clasificación , Neoplasias Cerebelosas/metabolismo , Niño , Preescolar , Femenino , Humanos , Masculino , Meduloblastoma/clasificación , Meduloblastoma/metabolismoRESUMEN
PURPOSE: Medulloblastoma in children can be categorized into at least four molecular subgroups, offering the potential for targeted therapeutic approaches to reduce treatment-related morbidities. Little is known about the role of tumor microenvironment in medulloblastoma or its contribution to these molecular subgroups. Tumor microenvironment has been shown to be an important source for therapeutic targets in both adult and pediatric neoplasms. In this study, we investigated the hypothesis that expression of genes related to tumor-associated macrophages (TAM) correlates with the medulloblastoma molecular subgroups and contributes to a diagnostic signature. METHODS: Gene-expression profiling using human exon array (n = 168) was analyzed to identify medulloblastoma molecular subgroups and expression of inflammation-related genes. Expression of 45 tumor-related and inflammation-related genes was analyzed in 83 medulloblastoma samples to build a gene signature predictive of molecular subgroups. TAMs in medulloblastomas (n = 54) comprising the four molecular subgroups were assessed by immunohistochemistry (IHC). RESULTS: A 31-gene medulloblastoma subgroup classification score inclusive of TAM-related genes (CD163 and CSF1R) was developed with a misclassification rate of 2%. Tumors in the Sonic Hedgehog (SHH) subgroup had increased expression of inflammation-related genes and significantly higher infiltration of TAMs than tumors in the Group 3 or Group 4 subgroups (P < 0.0001 and P < 0.0001, respectively). IHC data revealed a strong association between location of TAMs and proliferating tumor cells. CONCLUSIONS: These data show that SHH tumors have a unique tumor microenvironment among medulloblastoma subgroups. The interactions of TAMs and SHH medulloblastoma cells may contribute to tumor growth revealing TAMs as a potential therapeutic target.
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Neoplasias Cerebelosas/inmunología , Proteínas Hedgehog/metabolismo , Macrófagos/inmunología , Meduloblastoma/inmunología , Microambiente Tumoral/inmunología , Biomarcadores de Tumor/genética , Neoplasias Cerebelosas/patología , Niño , Preescolar , Femenino , Perfilación de la Expresión Génica , Humanos , Inflamación/inmunología , Masculino , Meduloblastoma/patología , Receptor de Factor Estimulante de Colonias de Macrófagos/antagonistas & inhibidoresRESUMEN
Many user localization technologies and methods have been proposed for either indoor or outdoor environments. However, each technology has its own drawbacks. Recently, many researches and designs have been proposed to build a combination of multiple localization technologies system which can provide higher precision results and solve the limitation in each localization technology alone. In this paper, a conceptual design of a general localization platform using combination of multiple localization technologies is introduced. The combination is realized by dividing spaces into grid points. To demonstrate this platform, a system with GPS, RFID, WiFi, and pedometer technologies is established. Experiment results show that the accuracy and availability are improved in comparison with each technology individually.
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Sistemas de Información Geográfica , Dispositivo de Identificación por Radiofrecuencia , Tecnología de Sensores Remotos , Tecnología Inalámbrica , Algoritmos , Ambiente , Modelos TeóricosRESUMEN
Ewing sarcoma family tumors (ESFT) are aggressive bone and soft tissue tumors that express EWS-ETS fusion genes as driver mutations. Although the histogenesis of ESFT is controversial, mesenchymal (MSC) and/or neural crest (NCSC) stem cells have been implicated as cells of origin. For the current study we evaluated the consequences of EWS-FLI1 expression in human embryonic stem cell-derived NCSC (hNCSC). Ectopic expression of EWS-FLI1 in undifferentiated hNCSC and their neuro-mesenchymal stem cell (hNC-MSC) progeny was readily tolerated and led to altered expression of both well established as well as novel EWS-FLI1 target genes. Importantly, whole genome expression profiling studies revealed that the molecular signature of established ESFT is more similar to hNCSC than any other normal tissue, including MSC, indicating that maintenance or reactivation of the NCSC program is a feature of ESFT pathogenesis. Consistent with this hypothesis, EWS-FLI1 induced hNCSC genes as well as the polycomb proteins BMI-1 and EZH2 in hNC-MSC. In addition, up-regulation of BMI-1 was associated with avoidance of cellular senescence and reversible silencing of p16. Together these studies confirm that, unlike terminally differentiated cells but consistent with bone marrow-derived MSC, NCSC tolerate expression of EWS-FLI1 and ectopic expression of the oncogene initiates transition to an ESFT-like state. In addition, to our knowledge this is the first demonstration that EWS-FLI1-mediated induction of BMI-1 and epigenetic silencing of p16 might be critical early initiating events in ESFT tumorigenesis.
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Células Madre Embrionarias/citología , Cresta Neural/citología , Sarcoma de Ewing/diagnóstico , Western Blotting , Diferenciación Celular , Senescencia Celular , Epigénesis Genética , Citometría de Flujo , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Silenciador del Gen , Humanos , Lentivirus/metabolismo , Modelos Genéticos , Células-Madre Neurales/citología , OncogenesRESUMEN
BACKGROUND: Some human cancers demonstrate cellular hierarchies in which tumor-initiating cancer stem cells generate progeny cells with reduced tumorigenic potential. This cancer stem cell population is proposed to be a source of therapy-resistant and recurrent disease. Ewing sarcoma family tumors (ESFT) are highly aggressive cancers in which drug-resistant, relapsed disease remains a significant clinical problem. Recently, the cell surface protein CD133 was identified as a putative marker of tumor-initiating cells in ESFT. We evaluated ESFT tumors and cell lines to determine if high levels of CD133 are associated with drug resistance. METHODS: Expression of the CD133-encoding PROM1 gene was determined by RT-PCR in ESFT tumors and cell lines. CD133 protein expression was assessed by western blot, FACS and/or immunostaining. Cell lines were FACS-sorted into CD133+ and CD133- fractions and proliferation, colony formation in soft agar, and in vivo tumorigenicity compared. Chemosensitivity was measured using MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy-methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assays. RESULTS: PROM1 expression was either absent or extremely low in most tumors. However, PROM1 was highly over-expressed in 4 of 48 cases. Two of the 4 patients with PROM1 over-expressing tumors rapidly succumbed to primary drug-resistant disease and two are long-term, event-free survivors. The expression of PROM1 in ESFT cell lines was similarly heterogeneous. The frequency of CD133+ cells ranged from 2-99% and, with one exception, no differences in the chemoresistance or tumorigenicity of CD133+ and CD133- cell fractions were detected. Importantly, however, the STA-ET-8.2 cell line was found to retain a cellular hierarchy in which relatively chemo-resistant, tumorigenic CD133+ cells gave rise to relatively chemo-sensitive, less tumorigenic, CD133- progeny. CONCLUSIONS: Up to 10% of ESFT express high levels of PROM1. In some tumors and cell lines the CD133+ fraction is relatively more drug-resistant, while in others there is no apparent difference between CD133+ and CD133- cells. These studies reveal heterogeneity in PROM1/CD133 expression in ESFT tumors and cell lines and confirm that high levels of PROM1 expression are, in at least some cases, associated with chemo-resistant disease. Further studies are required to elucidate the contribution of PROM1/CD133 expressing cells to therapeutic resistance in a large, prospective cohort of primary ESFT.
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Antígenos CD/biosíntesis , Regulación Neoplásica de la Expresión Génica , Glicoproteínas/biosíntesis , Sarcoma de Ewing/metabolismo , Antígeno AC133 , Animales , Antígenos CD/metabolismo , Separación Celular , Estudios de Cohortes , Resistencia a Antineoplásicos , Citometría de Flujo/métodos , Glicoproteínas/metabolismo , Humanos , Ratones , Ratones Endogámicos NOD , Ratones SCID , Péptidos/metabolismo , Recurrencia , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Deregulation of the polycomb group gene BMI-1 is implicated in the pathogenesis of many human cancers. In this study, we have investigated if the Ewing sarcoma family of tumors (ESFT) expresses BMI-1 and whether it functions as an oncogene in this highly aggressive group of bone and soft tissue tumors. Our data show that BMI-1 is highly expressed by ESFT cells and that, although it does not significantly affect proliferation or survival, BMI-1 actively promotes anchorage-independent growth in vitro and tumorigenicity in vivo. Moreover, we find that BMI-1 promotes the tumorigenicity of both p16 wild-type and p16-null cell lines, demonstrating that the mechanism of BMI-1 oncogenic function in ESFT is, at least in part, independent of CDKN2A repression. Expression profiling studies of ESFT cells following BMI-1 knockdown reveal that BMI-1 regulates the expression of hundreds of downstream target genes including, in particular, genes involved in both differentiation and development as well as cell-cell and cell-matrix adhesion. Gain and loss of function assays confirm that BMI-1 represses the expression of the adhesion-associated basement membrane protein nidogen 1. In addition, although BMI-1 promotes ESFT adhesion, nidogen 1 inhibits cellular adhesion in vitro. Together, these data support a pivotal role for BMI-1 ESFT pathogenesis and suggest that its oncogenic function in these tumors is in part mediated through modulation of adhesion pathways.