RESUMEN
Many cancers are characterized by gene fusions encoding oncogenic chimeric transcription factors (TFs) such as EWS::FLI1 in Ewing sarcoma (EwS). Here, we find that EWS::FLI1 induces the robust expression of a specific set of novel spliced and polyadenylated transcripts within otherwise transcriptionally silent regions of the genome. These neogenes (NGs) are virtually undetectable in large collections of normal tissues or non-EwS tumors and can be silenced by CRISPR interference at regulatory EWS::FLI1-bound microsatellites. Ribosome profiling and proteomics further show that some NGs are translated into highly EwS-specific peptides. More generally, we show that hundreds of NGs can be detected in diverse cancers characterized by chimeric TFs. Altogether, this study identifies the transcription, processing, and translation of novel, specific, highly expressed multi-exonic transcripts from otherwise silent regions of the genome as a new activity of aberrant TFs in cancer.
Asunto(s)
Carcinogénesis , Regulación Neoplásica de la Expresión Génica , Proteínas de Fusión Oncogénica , Proteína Proto-Oncogénica c-fli-1 , Factores de Transcripción , Carcinogénesis/genética , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica/genética , Silenciador del Gen , Genoma/genética , Genómica , Humanos , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/metabolismo , Oncogenes/genética , Proteína Proto-Oncogénica c-fli-1/genética , Proteína Proto-Oncogénica c-fli-1/metabolismo , Sarcoma de Ewing/genética , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/patología , Factores de Transcripción/genética , Transcripción Genética/genéticaRESUMEN
Cancer metastasis requires the transient activation of cellular programs enabling dissemination and seeding in distant organs1. Genetic, transcriptional and translational heterogeneity contributes to this dynamic process2,3. Metabolic heterogeneity has also been observed4, yet its role in cancer progression is less explored. Here we find that the loss of phosphoglycerate dehydrogenase (PHGDH) potentiates metastatic dissemination. Specifically, we find that heterogeneous or low PHGDH expression in primary tumours of patients with breast cancer is associated with decreased metastasis-free survival time. In mice, circulating tumour cells and early metastatic lesions are enriched with Phgdhlow cancer cells, and silencing Phgdh in primary tumours increases metastasis formation. Mechanistically, Phgdh interacts with the glycolytic enzyme phosphofructokinase, and the loss of this interaction activates the hexosamine-sialic acid pathway, which provides precursors for protein glycosylation. As a consequence, aberrant protein glycosylation occurs, including increased sialylation of integrin αvß3, which potentiates cell migration and invasion. Inhibition of sialylation counteracts the metastatic ability of Phgdhlow cancer cells. In conclusion, although the catalytic activity of PHGDH supports cancer cell proliferation, low PHGDH protein expression non-catalytically potentiates cancer dissemination and metastasis formation. Thus, the presence of PHDGH heterogeneity in primary tumours could be considered a sign of tumour aggressiveness.
Asunto(s)
Neoplasias de la Mama , Metástasis de la Neoplasia , Fosfoglicerato-Deshidrogenasa , Animales , Neoplasias de la Mama/patología , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Progresión de la Enfermedad , Femenino , Silenciador del Gen , Humanos , Ratones , Fosfoglicerato-Deshidrogenasa/genética , Serina/metabolismoRESUMEN
Most tumours have an aberrantly activated lipid metabolism1,2 that enables them to synthesize, elongate and desaturate fatty acids to support proliferation. However, only particular subsets of cancer cells are sensitive to approaches that target fatty acid metabolism and, in particular, fatty acid desaturation3. This suggests that many cancer cells contain an unexplored plasticity in their fatty acid metabolism. Here we show that some cancer cells can exploit an alternative fatty acid desaturation pathway. We identify various cancer cell lines, mouse hepatocellular carcinomas, and primary human liver and lung carcinomas that desaturate palmitate to the unusual fatty acid sapienate to support membrane biosynthesis during proliferation. Accordingly, we found that sapienate biosynthesis enables cancer cells to bypass the known fatty acid desaturation pathway that is dependent on stearoyl-CoA desaturase. Thus, only by targeting both desaturation pathways is the in vitro and in vivo proliferation of cancer cells that synthesize sapienate impaired. Our discovery explains metabolic plasticity in fatty acid desaturation and constitutes an unexplored metabolic rewiring in cancers.
Asunto(s)
Ácidos Grasos/química , Ácidos Grasos/metabolismo , Redes y Vías Metabólicas , Neoplasias/metabolismo , Neoplasias/patología , Animales , Línea Celular Tumoral , Membrana Celular/metabolismo , Proliferación Celular , Ácido Graso Desaturasas/metabolismo , Femenino , Células HEK293 , Humanos , Masculino , Ratones , Ácidos Oléicos/metabolismo , Palmitatos/metabolismo , Ácidos Palmíticos/metabolismo , Estearoil-CoA Desaturasa/metabolismoRESUMEN
Chronic myeloid leukaemia (CML) is a clonal myeloproliferative stem cell disorder characterized by the constitutively active BCR-ABL tyrosine kinase. The LIM and SH3 domain protein 1 (LASP1) has recently been identified as a novel BCR-ABL substrate and is associated with proliferation, migration, tumorigenesis and chemoresistance in several cancers. Furthermore, LASP1 was shown to bind to the chemokine receptor 4 (CXCR4), thought to be involved in mechanisms of relapse. In order to identify potential LASP1-mediated pathways and related factors that may help to further eradicate minimal residual disease (MRD), the effect of LASP1 on processes involved in progression and maintenance of CML was investigated. The present data indicate that not only overexpression of CXCR4, but also knockout of LASP1 contributes to proliferation, reduced apoptosis and migration as well as increased adhesive potential of K562 CML cells. Furthermore, LASP1 depletion in K562 CML cells leads to decreased cytokine release and reduced NK cell-mediated cytotoxicity towards CML cells. Taken together, these results indicate that in CML, reduced levels of LASP1 alone and in combination with high CXCR4 expression may contribute to TKI resistance.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas del Citoesqueleto/metabolismo , Resistencia a Antineoplásicos , Técnicas de Inactivación de Genes , Proteínas con Dominio LIM/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Inhibidores de Proteínas Quinasas/farmacología , Receptores CXCR4/metabolismo , Adenosina Trifosfato/metabolismo , Adhesión Celular/efectos de los fármacos , Muerte Celular/efectos de los fármacos , Degranulación de la Célula/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Mesilato de Imatinib/farmacología , Mesilato de Imatinib/uso terapéutico , Células K562 , Células Asesinas Naturales/efectos de los fármacos , Células Asesinas Naturales/metabolismo , Células Asesinas Naturales/fisiología , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Biosíntesis de Proteínas/efectos de los fármacos , Pirimidinas/farmacología , Pirimidinas/uso terapéutico , Transcripción Genética/efectos de los fármacos , Resultado del TratamientoRESUMEN
In prostate adenocarcinoma (PCa), distinction between indolent and aggressive disease is challenging. Around 50% of PCa are characterized by TMPRSS2-ERG (T2E)-fusion oncoproteins defining two molecular subtypes (T2E-positive/negative). However, current prognostic tests do not differ between both molecular subtypes, which might affect outcome prediction. To investigate gene-signatures associated with metastasis in T2E-positive and T2E-negative PCa independently, we integrated tumor transcriptomes and clinicopathological data of two cohorts (total n = 783), and analyzed metastasis-associated gene-signatures regarding the T2E-status. Here, we show that the prognostic value of biomarkers in PCa critically depends on the T2E-status. Using gene-set enrichment analyses, we uncovered that metastatic T2E-positive and T2E-negative PCa are characterized by distinct gene-signatures. In addition, by testing genes shared by several functional gene-signatures for their association with event-free survival in a validation cohort (n = 272), we identified five genes (ASPN, BGN, COL1A1, RRM2 and TYMS)-three of which are included in commercially available prognostic tests-whose high expression was significantly associated with worse outcome exclusively in T2E-negative PCa. Among these genes, RRM2 and TYMS were validated by immunohistochemistry in another validation cohort (n = 135), and several of them proved to add prognostic information to current clinicopathological predictors, such as Gleason score, exclusively for T2E-negative patients. No prognostic biomarkers were identified exclusively for T2E-positive tumors. Collectively, our study discovers that the T2E-status, which is per se not a strong prognostic biomarker, crucially determines the prognostic value of other biomarkers. Our data suggest that the molecular subtype needs to be considered when applying prognostic biomarkers for outcome prediction in PCa.
Asunto(s)
Adenocarcinoma/genética , Adenocarcinoma/mortalidad , Biomarcadores de Tumor , Proteínas de Fusión Oncogénica/genética , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/mortalidad , Adenocarcinoma/diagnóstico , Biología Computacional , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Inmunohistoquímica , Estimación de Kaplan-Meier , Masculino , Clasificación del Tumor , Metástasis de la Neoplasia , Estadificación de Neoplasias , Pronóstico , Neoplasias de la Próstata/diagnósticoRESUMEN
Soft tissue sarcomas (STSs) are heterogeneous cancers associated with poor prognosis due to high rates of local recurrence and metastasis. The programmed death receptor ligand 1 (PD-L1) is expressed in several cancers. PD-L1 interacts with its receptor, PD-1, on the surface of tumor-infiltrating lymphocytes (TILs), thereby attenuating anti-cancer immune response. Immune checkpoint inhibitors targeting this interaction have been established as effective anti-cancer drugs. However, studies on the PD-L1 and PD-1 expression status in STS are commonly limited by small sample size, analysis of single STS subtypes, or lack of combinatorial marker assessment. To overcome these limitations, we evaluated the expression patterns of intratumoral PD-L1, the number of TILs, their PD-1 expression, and associations with clinicopathological parameters in a large and comprehensive cohort of 225 samples comprising six STS subtypes. We found that nearly all STS subtypes showed PD-L1 expression on the tumor cells, albeit with a broad range of positivity across subtypes (50% angiosarcomas to 3% synovial sarcomas). Co-expression and correlation analyses uncovered that PD-L1 expression was associated with more PD-1-positive TILs (P < 0.001), higher tumor grading (P = 0.016), and worse patients' 5-year overall survival (P = 0.028). The results were in line with several publications on single STS subtypes, especially when comparing findings for STS with low and high mutational burden. In sum, the substantial portion of PD-L1 positivity, the co-occurrence of PD-1-positive TILs, and the association of PD-L1 with unfavorable clinical outcome provide rationales for immune checkpoint inhibition in patients with PD-L1-positive STS.
Asunto(s)
Antígeno B7-H1/metabolismo , Biomarcadores de Tumor/metabolismo , Receptor de Muerte Celular Programada 1/metabolismo , Sarcoma/metabolismo , Adolescente , Adulto , Anciano , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Pronóstico , Sarcoma/clasificación , Sarcoma/patología , Tasa de Supervivencia , Adulto JovenRESUMEN
Soft-tissue sarcomas are rare, heterogeneous, and often aggressive mesenchymal cancers. Many of them are associated with poor outcome, partially because biomarkers that can identify high-risk patients are lacking. Studies on sarcomas are often limited by small sample-sizes rendering the identification of biomarkers difficult when focusing on individual cohorts. However, the increasing number of publicly available 'omics' data opens inroads to overcome this obstacle. Here, we combine transcriptome analyses, immunohistochemistry, and functional assays to show that high adenosine monophosphate deaminase 2 (AMPD2) is a robust prognostic biomarker for worse outcome in undifferentiated pleomorphic sarcoma (UPS). Gene expression and survival data for UPS from two independent studies were subjected to survival association-testing. Genes, whose high expression was significantly correlated with worse outcome in both cohorts, were considered as biomarker candidates. The best candidate, AMPD2, was validated in a tissue microarray. Analysis of DNA copy-number data and matched transcriptomes indicated that high AMPD2 expression is significantly correlated with gains at the AMPD2 locus. Gene set enrichment analyses of AMPD2 co-expressed genes in both transcriptome datasets suggested that AMPD2-high UPS are enriched in tumorigenic signatures. Consistently, knockdown of AMPD2 by RNA interference in an UPS cell line inhibited proliferation in vitro and tumorigenicity in vivo. Collectively, we provide evidence that AMPD2 may serve as a biomarker for outcome prediction in UPS. Our study exemplifies how the integration of 'omics' data, immunohistochemistry, and functional experiments can identify novel biomarkers even in a rare sarcoma, which may serve as a blueprint for biomarker identification for other rare cancers.
Asunto(s)
AMP Desaminasa/genética , Biomarcadores de Tumor/genética , Genómica/métodos , Histiocitoma Fibroso Maligno/genética , AMP Desaminasa/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Animales , Biomarcadores de Tumor/metabolismo , Línea Celular Tumoral , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Histiocitoma Fibroso Maligno/metabolismo , Histiocitoma Fibroso Maligno/patología , Humanos , Estimación de Kaplan-Meier , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Persona de Mediana Edad , Pronóstico , Tratamiento con ARN de Interferencia/métodos , Ensayos Antitumor por Modelo de Xenoinjerto/métodos , Adulto JovenAsunto(s)
Biomarcadores de Tumor , Neoplasias Óseas/genética , Neoplasias Óseas/mortalidad , Regulación Neoplásica de la Expresión Génica , Redes Reguladoras de Genes , Sarcoma de Ewing/genética , Sarcoma de Ewing/mortalidad , Animales , Modelos Animales de Enfermedad , Perfilación de la Expresión Génica , Xenoinjertos , Humanos , Ratones , Estadificación de Neoplasias , Pronóstico , Sarcoma de Ewing/patologíaAsunto(s)
Biomarcadores de Tumor , Neoplasias Óseas/etiología , Ribonucleósido Difosfato Reductasa/genética , Sarcoma de Ewing/etiología , Animales , Neoplasias Óseas/diagnóstico , Neoplasias Óseas/terapia , Manejo de la Enfermedad , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Terapia Molecular Dirigida , Pronóstico , Piridinas/farmacología , Ribonucleósido Difosfato Reductasa/metabolismo , Sarcoma de Ewing/diagnóstico , Sarcoma de Ewing/mortalidad , Sarcoma de Ewing/terapia , Tiosemicarbazonas/farmacología , Ensayos Antitumor por Modelo de XenoinjertoAsunto(s)
Variaciones en el Número de Copia de ADN/genética , Proteínas de Fusión Oncogénica/genética , Proteína EWS de Unión a ARN/genética , Sarcoma de Ewing/genética , Antígenos Nucleares/genética , Antígenos de Protozoos/genética , Proteínas de Ciclo Celular , Inhibidor p16 de la Quinasa Dependiente de Ciclina , Inhibidor p18 de las Quinasas Dependientes de la Ciclina/genética , Epigenómica , Mutación de Línea Germinal , Humanos , Sarcoma de Ewing/patologíaRESUMEN
Neuroblastoma (NB) accounts for 15% of cancer-related deaths in childhood despite considerable therapeutic improvements. While several risk factors, including MYCN amplification and alterations in RAS and p53 pathway genes, have been defined in NB, the clinical outcome is very variable and difficult to predict. Since genes of the mechanistic target of rapamycin (mTOR) pathway are upregulated in MYCN-amplified NB, we aimed to define the predictive value of the mTOR substrate-encoding gene eukaryotic translation initiation factor 4E-binding protein 1 (EIF4EBP1) expression in NB patients. Using publicly available data sets, we found that EIF4EBP1 mRNA expression is positively correlated with MYCN expression and elevated in stage 4 and high-risk NB patients. In addition, high EIF4EBP1 mRNA expression is associated with reduced overall and event-free survival in the entire group of NB patients in three cohorts, as well as in stage 4 and high-risk patients. This was confirmed by monitoring the clinical value of 4EBP1 protein expression, which revealed that high levels of 4EBP1 are significantly associated with prognostically unfavorable NB histology. Finally, functional analyses revealed that EIF4EBP1 expression is transcriptionally controlled by MYCN binding to the EIF4EBP1 promoter in NB cells. Our data highlight that EIF4EBP1 is a direct transcriptional target of MYCN whose high expression is associated with poor prognosis in NB patients. Therefore, EIF4EBP1 may serve to better stratify patients with NB.
RESUMEN
Ewing sarcoma (EwS) is characterized by EWSR1-ETS fusion transcription factors converting polymorphic GGAA microsatellites (mSats) into potent neo-enhancers. Although the paucity of additional mutations makes EwS a genuine model to study principles of cooperation between dominant fusion oncogenes and neo-enhancers, this is impeded by the limited number of well-characterized models. Here we present the Ewing Sarcoma Cell Line Atlas (ESCLA), comprising whole-genome, DNA methylation, transcriptome, proteome, and chromatin immunoprecipitation sequencing (ChIP-seq) data of 18 cell lines with inducible EWSR1-ETS knockdown. The ESCLA shows hundreds of EWSR1-ETS-targets, the nature of EWSR1-ETS-preferred GGAA mSats, and putative indirect modes of EWSR1-ETS-mediated gene regulation, converging in the duality of a specific but plastic EwS signature. We identify heterogeneously regulated EWSR1-ETS-targets as potential prognostic EwS biomarkers. Our freely available ESCLA (http://r2platform.com/escla/) is a rich resource for EwS research and highlights the power of comprehensive datasets to unravel principles of heterogeneous gene regulation by chimeric transcription factors.
Asunto(s)
Sarcoma de Ewing , Humanos , Sarcoma de Ewing/genética , Multiómica , Oncogenes , Línea Celular , Factores de TranscripciónRESUMEN
Chromosomal instability (CIN) is a hallmark of cancer1. Yet, many childhood cancers, such as Ewing sarcoma (EwS), feature remarkably 'silent' genomes with minimal CIN2. Here, we show in the EwS model how uncoupling of mitosis and cytokinesis via targeting protein regulator of cytokinesis 1 (PRC1) or its activating polo-like kinase 1 (PLK1) can be employed to induce fatal genomic instability and tumor regression. We find that the EwS-specific oncogenic transcription factor EWSR1-FLI1 hijacks PRC1, which physiologically safeguards controlled cell division, through binding to a proximal enhancer-like GGAA-microsatellite, thereby promoting tumor growth and poor clinical outcome. Via integration of transcriptome-profiling and functional in vitro and in vivo experiments including CRISPR-mediated enhancer editing, we discover that high PRC1 expression creates a therapeutic vulnerability toward PLK1 inhibition that can repress even chemo-resistant EwS cells by triggering mitotic catastrophe.Collectively, our results exemplify how aberrant PRC1 activation by a dominant oncogene can confer malignancy but provide opportunities for targeted therapy, and identify PRC1 expression as an important determinant to predict the efficacy of PLK1 inhibitors being used in clinical trials.
Asunto(s)
Apoptosis/genética , Proteínas de Ciclo Celular/genética , Proteínas de Fusión Oncogénica/genética , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas/genética , Sarcoma de Ewing/genética , Animales , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Niño , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Células HEK293 , Humanos , Estimación de Kaplan-Meier , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Proteínas de Fusión Oncogénica/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Interferencia de ARN , Tratamiento con ARN de Interferencia/métodos , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/terapia , Transducción de Señal/genética , Ensayos Antitumor por Modelo de Xenoinjerto/métodos , Quinasa Tipo Polo 1RESUMEN
Metabolic reprogramming is a hallmark of cancer. Such reprogramming entails the up-regulation of the expression of specific mitochondrial proteins, thus increasing the burden on the mitochondrial protein quality control. However, very little is known about the specificity of interactions between mitochondrial chaperones and their clients, or to what extent the mitochondrial chaperone-client co-expression is coordinated. We hypothesized that a physical interaction between a chaperone and its client in mitochondria ought to be manifested in the co-expression pattern of both transcripts. Using The Cancer Genome Atlas (TCGA) gene expression data from 13 tumor entities, we constructed the mitochondrial chaperone-client co-expression network. We determined that the network is comprised of three distinct modules, each populated with unique chaperone-clients co-expression pairs belonging to distinct functional groups. Surprisingly, chaperonins HSPD1 and HSPE1, which are known to comprise a functional complex, each occupied a different module: HSPD1 co-expressed with tricarboxylic acid cycle cycle enzymes, while HSPE1 co-expressed with proteins involved in oxidative phosphorylation. Importantly, we found that the genes in each module were enriched for discrete transcription factor binding sites, suggesting the mechanism for the coordinated co-expression. We propose that our mitochondrial chaperone-client interactome can facilitate the identification of chaperones supporting specific mitochondrial pathways and bring forth a fundamental principle in metabolic adaptation.
RESUMEN
Oncogenesis of Ewing sarcoma (EwS), the second most common malignant bone tumor of childhood and adolescence, is dependent on the expression of chimeric EWSR1-ETS fusion oncogenes, most often EWSR1-FLI1 (E/F). E/F expression leads to dysregulation of focal adhesions (FAs) enhancing the migratory capacity of EwS cells. Here, we show that, in EwS cell lines and tissue samples, focal adhesion kinase (FAK) is expressed and phosphorylated at Y397 in an E/F-dependent way involving Ezrin. Employing different EwS cell lines as in vitro models, we found that key malignant properties of E/F are mediated via substrate-independent autophosphorylation of FAK on Y397. This phosphorylation results in enhanced FA formation, Rho-dependent cell migration, and impaired caspase-3-mediated apoptosis in vitro. Conversely, treatment with the FAK inhibitor 15 (1,2,4,5-benzenetetraamine tetrahydrochloride (Y15) enhanced caspase-mediated apoptosis and EwS cell migration, independent from the respective EWSR1-ETS fusion type, mimicking an anoikis-like phenotype and paralleling the effects of FAK siRNA knockdown. Our findings were confirmed in vivo using an avian chorioallantoic membrane model and provide a first rationale for the therapeutic use of FAK inhibitors to impair metastatic dissemination of EwS.
Asunto(s)
Apoptosis/genética , Neoplasias Óseas/metabolismo , Movimiento Celular/genética , Proteína-Tirosina Quinasas de Adhesión Focal/metabolismo , Adhesiones Focales/metabolismo , Sarcoma de Ewing/metabolismo , Compuestos de Anilina/farmacología , Animales , Apoptosis/efectos de los fármacos , Neoplasias Óseas/genética , Neoplasias Óseas/patología , Caspasa 3/metabolismo , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Supervivencia Celular/genética , Embrión de Pollo , Niño , Proteínas del Citoesqueleto/metabolismo , Proteína-Tirosina Quinasas de Adhesión Focal/antagonistas & inhibidores , Proteína-Tirosina Quinasas de Adhesión Focal/genética , Técnicas de Silenciamiento del Gen , Humanos , Ratones , Ratones Endogámicos NOD , Ratones Transgénicos , Proteínas de Fusión Oncogénica/genética , Fosforilación , Proteínas Proto-Oncogénicas c-ets/genética , ARN Interferente Pequeño , Proteína EWS de Unión a ARN/genética , Sarcoma de Ewing/genética , Sarcoma de Ewing/patología , Sarcoma de Ewing/secundario , Análisis de Matrices Tisulares , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Cancer cells display an increased plasticity in their lipid metabolism, which includes the conversion of palmitate to sapienate via the enzyme fatty acid desaturase 2 (FADS2). We find that FADS2 expression correlates with mammalian target of rapamycin (mTOR) signaling and sterol regulatory element-binding protein 1 (SREBP-1) activity across multiple cancer types and is prognostic in some cancer types. Accordingly, activating mTOR signaling by deleting tuberous sclerosis complex 2 (Tsc2) or overexpression of SREBP-1/2 is sufficient to increase FADS2 mRNA expression and sapienate metabolism in mouse embryonic fibroblasts (MEFs) and U87 glioblastoma cells, respectively. Conversely, inhibiting mTOR signaling decreases FADS2 expression and sapienate biosynthesis in MEFs with Tsc2 deletion, HUH7 hepatocellular carcinoma cells, and orthotopic HUH7 liver xenografts. In conclusion, we show that mTOR signaling and SREBP activity are sufficient to activate sapienate metabolism by increasing FADS2 expression. Consequently, targeting mTOR signaling can reduce sapienate metabolism in vivo.
Asunto(s)
Ácido Graso Desaturasas/genética , Regulación Neoplásica de la Expresión Génica , Ácidos Palmíticos/metabolismo , Transducción de Señal , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/biosíntesis , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Animales , Línea Celular Tumoral , Ácido Graso Desaturasas/metabolismo , Humanos , Ratones , Pronóstico , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transcripción GenéticaRESUMEN
A Correction to this paper has been published: https://doi.org/10.1038/s41467-020-20017-2.
RESUMEN
Ewing sarcoma (EwS) is an aggressive cancer displaying an undifferentiated small-round-cell histomorphology that can be easily confused with a broad spectrum of differential diagnoses. Using comparative transcriptomics and immunohistochemistry (IHC), we previously identified BCL11B and GLG1 as potential specific auxiliary IHC markers for EWSR1-FLI1-positive EwS. Herein, we aimed at validating the specificity of both markers in a far larger and independent cohort of EwS (including EWSR1-ERG-positive cases) and differential diagnoses. Furthermore, we evaluated their intra-tumoral expression heterogeneity. Thus, we stained tissue microarrays from 133 molecularly confirmed EwS cases and 320 samples from morphological mimics, as well as a series of patient-derived xenograft (PDX) models for BCL11B, GLG1, and CD99, and systematically assessed the immunoreactivity and optimal cut-offs for each marker. These analyses demonstrated that high BCL11B and/or GLG1 immunoreactivity in CD99-positive cases had a specificity of 97.5% and an accuracy of 87.4% for diagnosing EwS solely by IHC, and that the markers were expressed by EWSR1-ERG-positive EwS. Only little intra-tumoral heterogeneity in immunoreactivity was observed for differential diagnoses. These results indicate that BCL11B and GLG1 may help as specific auxiliary IHC markers in diagnosing EwS in conjunction with CD99, especially if confirmatory molecular diagnostics are not available.