RESUMO
Diverse genetic, epigenetic, and developmental programs drive glioblastoma, an incurable and poorly understood tumor, but their precise characterization remains challenging. Here, we use an integrative approach spanning single-cell RNA-sequencing of 28 tumors, bulk genetic and expression analysis of 401 specimens from the The Cancer Genome Atlas (TCGA), functional approaches, and single-cell lineage tracing to derive a unified model of cellular states and genetic diversity in glioblastoma. We find that malignant cells in glioblastoma exist in four main cellular states that recapitulate distinct neural cell types, are influenced by the tumor microenvironment, and exhibit plasticity. The relative frequency of cells in each state varies between glioblastoma samples and is influenced by copy number amplifications of the CDK4, EGFR, and PDGFRA loci and by mutations in the NF1 locus, which each favor a defined state. Our work provides a blueprint for glioblastoma, integrating the malignant cell programs, their plasticity, and their modulation by genetic drivers.
Assuntos
Neoplasias Encefálicas/genética , Plasticidade Celular/genética , Glioblastoma/genética , Adolescente , Idoso , Animais , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Linhagem da Célula/genética , Criança , Estudos de Coortes , Modelos Animais de Doenças , Feminino , Heterogeneidade Genética , Glioblastoma/patologia , Xenoenxertos , Humanos , Lactente , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Pessoa de Meia-Idade , Mutação , RNA-Seq , Análise de Célula Única/métodos , Microambiente Tumoral/genéticaRESUMO
Alterations in transcriptional regulators can orchestrate oncogenic gene expression programs in cancer. Here, we show that the BRG1/BRM-associated factor (BAF) chromatin remodeling complex, which is mutated in over 20% of human tumors, interacts with EWSR1, a member of a family of proteins with prion-like domains (PrLD) that are frequent partners in oncogenic fusions with transcription factors. In Ewing sarcoma, we find that the BAF complex is recruited by the EWS-FLI1 fusion protein to tumor-specific enhancers and contributes to target gene activation. This process is a neomorphic property of EWS-FLI1 compared to wild-type FLI1 and depends on tyrosine residues that are necessary for phase transitions of the EWSR1 prion-like domain. Furthermore, fusion of short fragments of EWSR1 to FLI1 is sufficient to recapitulate BAF complex retargeting and EWS-FLI1 activities. Our studies thus demonstrate that the physical properties of prion-like domains can retarget critical chromatin regulatory complexes to establish and maintain oncogenic gene expression programs.
Assuntos
Proteínas de Ligação a Calmodulina/química , Proteínas de Ligação a Calmodulina/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Proteína Proto-Oncogênica c-fli-1/metabolismo , Proteína EWS de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/metabolismo , Sarcoma de Ewing/genética , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Humanos , Células-Tronco Mesenquimais/metabolismo , Repetições de Microssatélites , Complexos Multiproteicos/química , Complexos Multiproteicos/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Proteínas Priônicas/metabolismo , Domínios Proteicos , Sarcoma de Ewing/patologiaRESUMO
Various types of repetitive sequences are dysregulated in cancer. In Ewing sarcoma, the oncogenic fusion protein EWS-FLI1 induces chromatin features typical of active enhancers at GGAA microsatellite repeats, but the function of these sites has not been directly demonstrated. Here, by combining nascent transcription profiling with epigenome editing, we found that a subset of GGAA microsatellite repeats is transcriptionally active in Ewing sarcoma and that silencing individual repeats abolishes local nascent transcription and leads to markedly reduced expression of putative target genes. Epigenome silencing of these repeat sites does not affect gene expression in unrelated cells, can prevent the induction of gene expression by EWS-FLI1, and, in the case of a GGAA repeat that controls SOX2 expression from a distance of 470 kb, is sufficient to impair the growth of Ewing sarcoma xenografts. Using an experimental approach that is broadly applicable to testing different types of repetitive genomic elements, our study directly demonstrates that specific repeat microsatellites can have critical gene regulation functions in cancer and thus represent tumor-specific vulnerabilities that may be exploited to develop new therapies.
Assuntos
Neoplasias Ósseas/genética , Elementos Facilitadores Genéticos , Regulação Neoplásica da Expressão Gênica , Inativação Gênica , Repetições de Microssatélites , Proteínas de Fusão Oncogênica/metabolismo , Proteína Proto-Oncogênica c-fli-1/metabolismo , Proteína EWS de Ligação a RNA/metabolismo , Sarcoma de Ewing/genética , Animais , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Células Cultivadas , Cromatina/metabolismo , Proteína Homeobox Nkx-2.2 , Proteínas de Homeodomínio/biossíntese , Proteínas de Homeodomínio/genética , Humanos , Células-Tronco Mesenquimais/metabolismo , Camundongos , RNA não Traduzido/biossíntese , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/patologia , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Transcrição Gênica , Células Tumorais Cultivadas , Proteínas de Peixe-ZebraRESUMO
IMPs, also known as insulin-like growth factor 2 (IGF2) messenger RNA (mRNA)-binding proteins (IGF2BPs), are highly conserved oncofetal RNA-binding proteins (RBPs) that regulate RNA processing at several levels, including localization, translation, and stability. Three mammalian IMP paralogs (IMP1-3) have been identified that are expressed in most organs during embryogenesis, where they are believed to play an important role in cell migration, metabolism, and stem cell renewal. Whereas some IMP2 expression is retained in several adult mouse organs, IMP1 and IMP3 are either absent or expressed at very low levels in most tissues after birth. However, all three paralogs can be re-expressed upon malignant transformation and are found in a broad range of cancer types where their expression often correlates with poor prognosis. IMPs appear to resume their physiological functions in malignant cells, which not only contribute to tumor progression but participate in the establishment and maintenance of tumor cell hierarchies. This review summarizes our current understanding of the functions of IMPs during normal development and focuses on a series of recent observations that have provided new insight into how their physiological functions enable IMPs to play a potentially key role in cancer stem cell maintenance and tumor growth.
Assuntos
Desenvolvimento Embrionário/genética , Neoplasias/genética , Neoplasias/fisiopatologia , Proteínas de Ligação a RNA/metabolismo , Células-Tronco/fisiologia , Animais , Regulação da Expressão Gênica no Desenvolvimento , Regulação Neoplásica da Expressão Gênica , Humanos , Processamento Pós-Transcricional do RNA/genética , Proteínas de Ligação a RNA/genética , Células-Tronco/metabolismoRESUMO
Mesenchymal stem or stromal cells (MSCs) are pluripotent cells implicated in a broad range of physiological events, including organogenesis and maintenance of tissue homeostasis as well as tissue regeneration and repair. Because their current definition is somewhat loose - based primarily on their ability to differentiate into a variety of mesenchymal tissues, adhere to plastic, and express, or lack, a handful of cell surface markers - MSCs likely encompass several subpopulations, which may have diverse properties. Their diversity may explain, at least in part, the pleiotropic functions that they display in different physiological and pathological settings. In the context of tissue injury, MSCs can respectively promote and attenuate inflammation during the early and late phases of tissue repair. They may thereby act as sensors of the inflammatory response and secrete mediators that boost or temper the response as required by the stage of the reparatory and regenerative process. MSCs are also implicated in regulating tumor development, in which they are increasingly recognized to play a complex role. Thus, MSCs can both promote and constrain tumor progression by directly affecting tumor cells via secreted mediators and cell-cell interactions and by modulating the innate and adaptive immune response. This review summarizes our current understanding of MSC involvement in tumor development and highlights the mechanistic underpinnings of their implication in tumor growth and progression. © 2020 Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Assuntos
Progressão da Doença , Inflamação/patologia , Células-Tronco Mesenquimais/patologia , Neoplasias/patologia , Comunicação Celular/fisiologia , Humanos , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/imunologiaRESUMO
Growth of numerous cancer types is believed to be driven by a subpopulation of poorly differentiated cells, often referred to as cancer stem cells (CSCs), that have the capacity for self-renewal, tumor initiation, and generation of nontumorigenic progeny. Despite their potentially key role in tumor establishment and maintenance, the energy requirements of these cells and the mechanisms that regulate their energy production are unknown. Here, we show that the oncofetal insulin-like growth factor 2 mRNA-binding protein 2 (IMP2, IGF2BP2) regulates oxidative phosphorylation (OXPHOS) in primary glioblastoma (GBM) sphere cultures (gliomaspheres), an established in vitro model for CSC expansion. We demonstrate that IMP2 binds several mRNAs that encode mitochondrial respiratory chain complex subunits and that it interacts with complex I (NADH:ubiquinone oxidoreductase) proteins. Depletion of IMP2 in gliomaspheres decreases their oxygen consumption rate and both complex I and complex IV activity that results in impaired clonogenicity in vitro and tumorigenicity in vivo. Importantly, inhibition of OXPHOS but not of glycolysis abolishes GBM cell clonogenicity. Our observations suggest that gliomaspheres depend on OXPHOS for their energy production and survival and that IMP2 expression provides a key mechanism to ensure OXPHOS maintenance by delivering respiratory chain subunit-encoding mRNAs to mitochondria and contributing to complex I and complex IV assembly.
Assuntos
Glioblastoma/metabolismo , Células-Tronco Neoplásicas/metabolismo , Fosforilação Oxidativa , Proteínas de Ligação a RNA/metabolismo , Animais , Encéfalo/metabolismo , Hipóxia Celular/fisiologia , Linhagem Celular , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Mitocôndrias/metabolismo , Fosforilação Oxidativa/efeitos dos fármacos , Ligação Proteica , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Proteínas de Ligação a RNA/genética , Rotenona/farmacologia , Células Tumorais Cultivadas , Desacopladores/farmacologiaAssuntos
Neoplasias Ósseas , Proteínas de Fusão Oncogênica/metabolismo , Proteína Proto-Oncogênica c-fli-1/metabolismo , Proteína EWS de Ligação a RNA/metabolismo , Sarcoma de Ewing , Antineoplásicos/uso terapêutico , Neoplasias Ósseas/genética , Neoplasias Ósseas/terapia , Terapia Combinada , Metilação de DNA , DNA de Neoplasias/metabolismo , Regulação da Expressão Gênica , Humanos , Mutação , Polimorfismo Genético , Prognóstico , Sarcoma de Ewing/genética , Sarcoma de Ewing/terapia , Supressão Genética , Translocação GenéticaRESUMO
Clinical responses to anticancer therapies are often restricted to a subset of patients. In some cases, mutated cancer genes are potent biomarkers for responses to targeted agents. Here, to uncover new biomarkers of sensitivity and resistance to cancer therapeutics, we screened a panel of several hundred cancer cell lines--which represent much of the tissue-type and genetic diversity of human cancers--with 130 drugs under clinical and preclinical investigation. In aggregate, we found that mutated cancer genes were associated with cellular response to most currently available cancer drugs. Classic oncogene addiction paradigms were modified by additional tissue-specific or expression biomarkers, and some frequently mutated genes were associated with sensitivity to a broad range of therapeutic agents. Unexpected relationships were revealed, including the marked sensitivity of Ewing's sarcoma cells harbouring the EWS (also known as EWSR1)-FLI1 gene translocation to poly(ADP-ribose) polymerase (PARP) inhibitors. By linking drug activity to the functional complexity of cancer genomes, systematic pharmacogenomic profiling in cancer cell lines provides a powerful biomarker discovery platform to guide rational cancer therapeutic strategies.
Assuntos
Resistencia a Medicamentos Antineoplásicos/genética , Ensaios de Seleção de Medicamentos Antitumorais , Genes Neoplásicos/genética , Marcadores Genéticos/genética , Genoma Humano/genética , Neoplasias/tratamento farmacológico , Neoplasias/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/genética , Genômica , Humanos , Indóis/farmacologia , Neoplasias/patologia , Proteínas de Fusão Oncogênica/genética , Farmacogenética , Ftalazinas/farmacologia , Piperazinas/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases , Proteína Proto-Oncogênica c-fli-1/genética , Proteína EWS de Ligação a RNA/genética , Sarcoma de Ewing/tratamento farmacológico , Sarcoma de Ewing/genética , Sarcoma de Ewing/patologiaRESUMO
Cancer stem cells (CSCs) display plasticity and self-renewal properties reminiscent of normal tissue stem cells, but the events responsible for their emergence remain obscure. We recently identified CSCs in Ewing sarcoma family tumors (ESFTs) and showed that they retain mesenchymal stem cell (MSC) plasticity. In the present study, we addressed the mechanisms that underlie ESFT CSC development. We show that the EWS-FLI-1 fusion gene, associated with 85%-90% of ESFTs and believed to initiate their pathogenesis, induces expression of the embryonic stem cell (ESC) genes OCT4, SOX2, and NANOG in human pediatric MSCs (hpMSCs) but not in their adult counterparts. Moreover, under appropriate culture conditions, hpMSCs expressing EWS-FLI-1 generate a cell subpopulation displaying ESFT CSC features in vitro. We further demonstrate that induction of the ESFT CSC phenotype is the result of the combined effect of EWS-FLI-1 on its target gene expression and repression of microRNA-145 (miRNA145) promoter activity. Finally, we provide evidence that EWS-FLI-1 and miRNA-145 function in a mutually repressive feedback loop and identify their common target gene, SOX2, in addition to miRNA145 itself, as key players in ESFT cell differentiation and tumorigenicity. Our observations provide insight for the first time into the mechanisms whereby a single oncogene can reprogram primary cells to display a CSC phenotype.
Assuntos
Reprogramação Celular , Regulação Neoplásica da Expressão Gênica , Células-Tronco Mesenquimais/citologia , MicroRNAs/metabolismo , Proteína Proto-Oncogênica c-fli-1/metabolismo , Proteína EWS de Ligação a RNA/metabolismo , Fatores de Transcrição SOXB1/metabolismo , Adolescente , Adulto , Diferenciação Celular , Linhagem Celular Tumoral , Criança , Proteínas de Homeodomínio/metabolismo , Humanos , Proteína Homeobox Nanog , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/metabolismo , Fator 3 de Transcrição de Octâmero/metabolismo , Fenótipo , Sarcoma de Ewing/fisiopatologia , Células Tumorais CultivadasRESUMO
Solid tumor growth triggers a wound healing response. Similar to wound healing, fibroblasts in the tumor stroma differentiate into myofibroblasts (also referred to as cancer-associated fibroblasts) primarily, but not exclusively, in response to transforming growth factor-ß (TGF-ß). Myofibroblasts in turn enhance tumor progression by remodeling the stroma. Among proteases implicated in stroma remodeling, matrix metalloproteinases (MMPs), including MMP-9, play a prominent role. Recent evidence indicates that MMP-9 recruitment to the tumor cell surface enhances tumor growth and invasion. In the present work, we addressed the potential relevance of MMP-9 recruitment to and activity at the surface of fibroblasts. We show that recruitment of MMP-9 to the fibroblast cell surface occurs through its fibronectin-like (FN) domain and that the molecule responsible for the recruitment is lysyl hydroxylase 3 (LH3). Functional assays suggest that both pro- and active MMP-9 trigger α-smooth muscle actin expression in cultured fibroblasts, reflecting myofibroblast differentiation, possibly as a result of TGF-ß activation. Moreover, the recombinant FN domain inhibited both MMP-9-induced TGF-ß activation and α-smooth muscle actin expression by displacing MMP-9 from the fibroblast cell surface. Together our results uncover LH3 as a new docking receptor of MMP-9 on the fibroblast cell surface and demonstrate that the MMP-9 FN domain is essential for the interaction. They also show that the recombinant FN domain inhibits MMP-9-induced TGF-ß activation and fibroblast differentiation, providing a potentially attractive therapeutic reagent toward attenuating tumor progression where MMP-9 activity is strongly implicated.
Assuntos
Fibroblastos/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Pró-Colágeno-Lisina 2-Oxoglutarato 5-Dioxigenase/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Células CHO , Diferenciação Celular , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Separação Celular , Cricetinae , Cricetulus , Citometria de Fluxo , Células HEK293 , Humanos , Fígado/metabolismo , Microscopia de Fluorescência , Miofibroblastos/citologia , Proteínas Recombinantes/metabolismo , Microambiente TumoralRESUMO
No abstract available.
Assuntos
Centros Médicos Acadêmicos , Educação de Pós-Graduação em Medicina , Humanos , Centros Médicos Acadêmicos/economia , Centros Médicos Acadêmicos/organização & administração , Educação de Pós-Graduação em Medicina/economia , Suíça , Pesquisa Biomédica/economiaRESUMO
CIC-DUX4-rearranged sarcoma (CDS) is a rare and aggressive soft tissue tumor that occurs most frequently in young adults. The key oncogenic driver of this disease is the expression of the CIC-DUX4 fusion protein as a result of chromosomal rearrangements. CIC-DUX4 displays chromatin binding properties, and is therefore believed to function as an aberrant transcription factor. However, the chromatin remodeling events induced by CIC-DUX4 are not well understood, limiting our ability to identify new mechanism-based therapeutic strategies for these patients. Here, we generated a genome-wide profile of CIC-DUX4 DNA occupancy and associated chromatin states in human CDS cell models and primary tumors. Combining chromatin profiling, proximity ligation assays, as well as genetic and pharmacological perturbations, we show that CIC-DUX4 operates as a potent transcriptional activator at its binding sites. This property is in contrast with the repressive function of the wild-type CIC protein, and is mainly mediated through the direct interaction of CIC-DUX4 with the acetyltransferase p300. In keeping with this, we show p300 to be essential for CDS tumor cell proliferation; additionally, we find its pharmacological inhibition to significantly impact tumor growth in vitro and in vivo. Taken together, our study elucidates the mechanisms underpinning CIC-DUX4-mediated transcriptional regulation.
RESUMO
The development of targeted therapies offers new hope for patients affected by incurable cancer. However, multiple challenges persist, notably in controlling tumor cell plasticity in patients with refractory and metastatic illness. Neuroblastoma (NB) is an aggressive pediatric malignancy originating from defective differentiation of neural crest-derived progenitors with oncogenic activity due to genetic and epigenetic alterations and remains a clinical challenge for high-risk patients. To identify critical genes driving NB aggressiveness, we performed combined chromatin and transcriptome analyses on matched patient-derived xenografts (PDXs), spheroids, and differentiated adherent cultures derived from metastatic MYCN nonamplified tumors. Bone marrow kinase on chromosome X (BMX) was identified among the most differentially regulated genes in PDXs and spheroids versus adherent models. BMX expression correlated with high tumor stage and poor patient survival and was crucial to the maintenance of the self-renewal and tumorigenic potential of NB spheroids. Moreover, BMX expression positively correlated with the mesenchymal NB cell phenotype, previously associated with increased chemoresistance. Finally, BMX inhibitors readily reversed this cellular state, increased the sensitivity of NB spheroids toward chemotherapy, and partially reduced tumor growth in a preclinical NB model. Altogether, our study identifies BMX as a promising innovative therapeutic target for patients with high-risk MYCN nonamplified NB.
Assuntos
Proteína Proto-Oncogênica N-Myc , Neuroblastoma , Esferoides Celulares , Neuroblastoma/genética , Neuroblastoma/patologia , Neuroblastoma/tratamento farmacológico , Neuroblastoma/metabolismo , Humanos , Proteína Proto-Oncogênica N-Myc/genética , Proteína Proto-Oncogênica N-Myc/metabolismo , Animais , Esferoides Celulares/patologia , Esferoides Celulares/metabolismo , Esferoides Celulares/efeitos dos fármacos , Camundongos , Ensaios Antitumorais Modelo de Xenoenxerto , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão GênicaRESUMO
Securin and separase play a key role in sister chromatid separation during anaphase. However, a growing body of evidence suggests that in addition to regulating chromosome segregation, securin and separase display functions implicated in membrane traffic in Caenorhabditis elegans and Drosophila. Here we show that in mammalian cells both securin and separase associate with membranes and that depletion of either protein causes robust swelling of the trans-Golgi network (TGN) along with the appearance of large endocytic vesicles in the perinuclear region. These changes are accompanied by diminished constitutive protein secretion as well as impaired receptor recycling and degradation. Unexpectedly, cells depleted of securin or separase display defective acidification of early endosomes and increased membrane recruitment of vacuolar (V-) ATPase complexes, mimicking the effect of the specific V-ATPase inhibitor Bafilomycin A1. Taken together, our findings identify a new functional role of securin and separase in the modulation of membrane traffic and protein secretion that implicates regulation of V-ATPase assembly and function.
Assuntos
Proteínas de Ciclo Celular/metabolismo , Membrana Celular/metabolismo , Endopeptidases/metabolismo , Endossomos/química , Proteínas de Neoplasias/metabolismo , Animais , Autofagia/fisiologia , Linhagem Celular , Proteínas de Drosophila , Endossomos/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Securina , Separase , ATPases Vacuolares Próton-Translocadoras/metabolismo , Proteínas rab5 de Ligação ao GTP/metabolismo , Rede trans-Golgi/metabolismoRESUMO
Cell fate transitions observed in embryonic development involve changes in three-dimensional genomic organization that provide proper lineage specification. Whether similar events occur within tumor cells and contribute to cancer evolution remains largely unexplored. We modeled this process in the pediatric cancer Ewing sarcoma and investigated high-resolution looping and large-scale nuclear conformation changes associated with the oncogenic fusion protein EWS-FLI1. We show that chromatin interactions in tumor cells are dominated by highly connected looping hubs centered on EWS-FLI1 binding sites, which directly control the activity of linked enhancers and promoters to establish oncogenic expression programs. Conversely, EWS-FLI1 depletion led to the disassembly of these looping networks and a widespread nuclear reorganization through the establishment of new looping patterns and large-scale compartment configuration matching those observed in mesenchymal stem cells, a candidate Ewing sarcoma progenitor. Our data demonstrate that major architectural features of nuclear organization in cancer cells can depend on single oncogenes and are readily reversed to reestablish latent differentiation programs.
Assuntos
Sarcoma de Ewing , Criança , Humanos , Sarcoma de Ewing/genética , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/patologia , Cromatina/genética , Linhagem Celular Tumoral , Proteína EWS de Ligação a RNA/genética , Proteína EWS de Ligação a RNA/metabolismo , Sítios de Ligação , Diferenciação Celular , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Regulação Neoplásica da Expressão GênicaRESUMO
Malignant tumors commonly display necrosis, which invariably triggers an inflammatory response that supports tumor growth. However, the effect on tumor cells of necrotic debris, or damage-associated molecular patterns (DAMPs) released by dying cells is unknown. Here, we addressed the effect of DAMPs on primary Ewing sarcoma (EwS) cells and cell lines grown in 3D (spheroids) and 2D culture. We show that DAMPs promote the growth of EwS spheroids but not 2D cultures and that the underlying mechanism implicates an increase in cholesterol load in spheroids. In contrast, stimulation of the nucleic acid sensor signaling platform STING by its ligand cyclic GMP-AMP decreases the tumor cell cholesterol load and reduces their tumor initiating ability. Overexpression of STING or stimulation with cyclic GMP-AMP opposes the growth stimulatory effect of DAMPs and synergizes with the cholesterol synthesis inhibitor simvastatin to inhibit tumor growth. Our observations show that modulation of cholesterol homeostasis is a major effect of necrotic cell debris and STING and suggest that combining STING agonists with statins may help control tumor growth.
Assuntos
Colesterol/metabolismo , Homeostase , Proteínas de Membrana/metabolismo , Necrose/metabolismo , Neoplasias/etiologia , Neoplasias/metabolismo , Alarminas/metabolismo , Apoptose , Biomarcadores , Linhagem Celular Tumoral , Gerenciamento Clínico , Suscetibilidade a Doenças , Regulação Neoplásica da Expressão Gênica , Humanos , Metabolismo dos Lipídeos , Neoplasias/patologia , Neoplasias/terapia , Esferoides Celulares , Células Tumorais CultivadasRESUMO
Most cancer cells have high need for nicotinamide adenine dinucleotide (NAD+) to sustain their survival. This led to the development of inhibitors of nicotinamide (NAM) phosphoribosyltransferase (NAMPT), the rate-limiting NAD+ biosynthesis enzyme from NAM. Such inhibitors kill cancer cells in preclinical studies but failed in clinical ones. To identify parameters that could negatively affect the therapeutic efficacy of NAMPT inhibitors and propose therapeutic strategies to circumvent such failure, we performed metabolomics analyses in tumor environment and explored the effect of the interaction between microbiota and cancer cells. Here we show that tumor environment enriched in vitamin B3 (NAM) or nicotinic acid (NA) significantly lowers the anti-tumor efficacy of APO866, a prototypic NAMPT inhibitor. Additionally, bacteria (from the gut, or in the medium) can convert NAM into NA and thus fuel an alternative NAD synthesis pathway through NA. This leads to the rescue from NAD depletion, prevents reactive oxygen species production, preserves mitochondrial integrity, blunts ATP depletion, and protects cancer cells from death.Our data in an in vivo preclinical model reveal that antibiotic therapy down-modulating gut microbiota can restore the anti-cancer efficacy of APO866. Alternatively, NAphosphoribosyltransferase inhibition may restore anti-cancer activity of NAMPT inhibitors in the presence of gut microbiota and of NAM in the diet.
Assuntos
Microbioma Gastrointestinal , Leucemia , Neoplasias , Linhagem Celular Tumoral , Citocinas/metabolismo , Humanos , NAD/metabolismo , Niacinamida/farmacologia , Niacinamida/uso terapêutico , Nicotinamida Fosforribosiltransferase/metabolismoRESUMO
Oncogenic fusion proteins generated by chromosomal translocations play major roles in cancer. Among them, fusions between EWSR1 and transcription factors generate oncogenes with powerful chromatin regulatory activities, capable of establishing complex gene expression programs in permissive precursor cells. Here we define the epigenetic and 3D connectivity landscape of Clear Cell Sarcoma, an aggressive cancer driven by the EWSR1-ATF1 fusion gene. We find that EWSR1-ATF1 displays a distinct DNA binding pattern that requires the EWSR1 domain and promotes ATF1 retargeting to new distal sites, leading to chromatin activation and the establishment of a 3D network that controls oncogenic and differentiation signatures observed in primary CCS tumors. Conversely, EWSR1-ATF1 depletion results in a marked reconfiguration of 3D connectivity, including the emergence of regulatory circuits that promote neural crest-related developmental programs. Taken together, our study elucidates the epigenetic mechanisms utilized by EWSR1-ATF1 to establish regulatory networks in CCS, and points to precursor cells in the neural crest lineage as candidate cells of origin for these tumors.
Assuntos
Sarcoma de Células Claras , Neoplasias de Tecidos Moles , Carcinogênese/genética , Cromatina/genética , Humanos , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Oncogenes , Proteína EWS de Ligação a RNA/genética , Sarcoma de Células Claras/genética , Sarcoma de Células Claras/patologia , Neoplasias de Tecidos Moles/genéticaRESUMO
CD44 is a facultative cell surface proteoglycan that serves as the principal cell surface receptor for hyaluronan (HA). Studies have shown that in addition to participating in numerous signaling pathways, CD44 becomes internalized upon engagement by ligand and that a portion of its intracellular domain can translocate to the nucleus where it is believed to play a functional role in cell proliferation and survival. However, the mechanisms whereby fragments of CD44 enter the nucleus have not been elucidated. Here we show that CD44 interacts with two import receptors of the importin ß superfamily, importin ß itself and transportin. Inhibition of importin ß-dependent transport failed to block CD44 accumulation in the nucleus. By contrast, inhibition of the transportin-dependent pathway abrogated CD44 import. Mutagenesis of the intracellular domain of CD44 revealed that the 20 membrane-proximal residues contain sequences required for transportin-mediated nuclear transport. Our observations provide evidence that CD44 interacts with importin family members and identify the transportin-dependent pathway as the mechanism whereby full-length CD44 enters the nucleus.