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Glioblastoma (GBM) is the deadliest form of primary brain tumor with limited treatment options. Recent studies have profiled GBM tumor heterogeneity, revealing numerous axes of variation that explain the molecular and spatial features of the tumor. Here, we seek to bridge descriptive characterization of GBM cell type heterogeneity with the functional role of individual populations within the tumor. Our lens leverages a gene program-centric meta-atlas of published transcriptomic studies to identify commonalities between diverse tumors and cell types in order to decipher the mechanisms that drive them. This approach led to the discovery of a tumor-derived stem cell population with mixed vascular and neural stem cell features, termed a neurovascular progenitor (NVP). Following in situ validation and molecular characterization of NVP cells in GBM patient samples, we characterized their function in vivo. Genetic depletion of NVP cells resulted in altered tumor cell composition, fewer cycling cells, and extended survival, underscoring their critical functional role. Clonal analysis of primary patient tumors in a human organoid tumor transplantation system demonstrated that the NVP has dual potency, generating both neuronal and vascular tumor cells. Although NVP cells comprise a small fraction of the tumor, these clonal analyses demonstrated that they strongly contribute to the total number of cycling cells in the tumor and generate a defined subset of the whole tumor. This study represents a paradigm by which cell type-specific interrogation of tumor populations can be used to study functional heterogeneity and therapeutically targetable vulnerabilities of GBM.
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BACKGROUND: Chimeric antigen receptor (CAR)-T cell therapies targeting glioblastoma (GBM)-associated antigens such as interleukin-13 receptor subunit alpha-2 (IL-13Rα2) have achieved limited clinical efficacy to date, in part due to an immunosuppressive tumor microenvironment (TME) characterized by inhibitory molecules such as transforming growth factor-beta (TGF-ß). The aim of this study was to engineer more potent GBM-targeting CAR-T cells by countering TGF-ß-mediated immune suppression in the TME. METHODS: We engineered a single-chain, bispecific CAR targeting IL-13Rα2 and TGF-ß, which programs tumor-specific T cells to convert TGF-ß from an immunosuppressant to an immunostimulant. Bispecific IL-13Rα2/TGF-ß CAR-T cells were evaluated for efficacy and safety against both patient-derived GBM xenografts and syngeneic models of murine glioma. RESULTS: Treatment with IL-13Rα2/TGF-ß CAR-T cells leads to greater T-cell infiltration and reduced suppressive myeloid cell presence in the tumor-bearing brain compared to treatment with conventional IL-13Rα2 CAR-T cells, resulting in improved survival in both patient-derived GBM xenografts and syngeneic models of murine glioma. CONCLUSION: Our findings demonstrate that by reprogramming tumor-specific T-cell responses to TGF-ß, bispecific IL-13Rα2/TGF-ß CAR-T cells resist and remodel the immunosuppressive TME to drive potent anti-tumor responses in GBM.
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Glioblastoma (GBM) is the most common malignant primary brain tumor and remains incurable. Previous work has shown that systemic administration of Decitabine (DAC) induces sufficient expression of cancer-testis antigens (CTA) in GBM for targeting by adoptive T-cell therapy in vivo. However, the mechanisms by which DAC enhances immunogenicity in GBM remain to be elucidated. Using New York esophageal squamous cell carcinoma 1 (NY-ESO-1) as a representative inducible CTA, we demonstrate in patient tissue, immortalized glioma cells, and primary patient-derived gliomaspheres that basal CTA expression is restricted by promoter hypermethylation in gliomas. DAC treatment of glioma cells specifically inhibits DNA methylation silencing to render NY-ESO-1 and other CTA into inducible tumor antigens at single-cell resolution. Functionally, NY-ESO-1 T-cell receptor-engineered effector cell targeting of DAC-induced antigen in primary glioma cells promotes specific and polyfunctional T-cell cytokine profiles. In addition to induction of CTA, DAC concomitantly reactivates tumor-intrinsic human endogenous retroviruses, interferon response signatures, and MHC-I. Overall, we demonstrate that DAC induces targetable tumor antigen and enhances T-cell functionality against GBM, ultimately contributing to the improvement of targeted immune therapies in glioma. SIGNIFICANCE: This study dissects the tumor-intrinsic epigenetic and transcriptional mechanisms underlying enhanced T-cell functionality targeting decitabine-induced cancer-testis antigens in glioma. Our findings demonstrate concomitant induction of tumor antigens, reactivation of human endogenous retroviruses, and stimulation of interferon signaling as a mechanistic rationale to epigenetically prime human gliomas to immunotherapeutic targeting.
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Antígenos de Neoplasias , Neoplasias Encefálicas , Decitabina , Retrovirus Endógenos , Epigénesis Genética , Glioma , Humanos , Antígenos de Neoplasias/inmunología , Antígenos de Neoplasias/genética , Decitabina/farmacología , Decitabina/uso terapéutico , Glioma/inmunología , Glioma/genética , Retrovirus Endógenos/genética , Neoplasias Encefálicas/inmunología , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Metilación de ADN , Línea Celular Tumoral , Análisis de la Célula Individual , Regulación Neoplásica de la Expresión Génica , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Regiones Promotoras Genéticas , Glioblastoma/inmunología , Glioblastoma/genética , Glioblastoma/patologíaRESUMEN
IDH1mut gliomas produce high levels of D-2-hydroxyglutarate (D-2-HG), an oncometabolite capable of inhibiting α-ketoglutarate-dependent dioxygenases critical to a range of cellular functions involved in gliomagenesis. IDH1mut gliomas also exhibit slower growth rates and improved treatment sensitivity compared with their IDH1wt counterparts. This study explores the mechanism driving apparent reduced growth in IDH1mut gliomas. Specifically, we investigated the relationship between IDH1mut and the RNA N6-methyladenosine (m6A) demethylases FTO and ALKBH5, and their potential for therapeutic targeting. We investigated the role of D-2-HG and m6A in tumor proliferation/viability using glioma patient tumor samples, patient-derived gliomaspheres, and U87 cells, as well as with mouse intracranial IDH1wt gliomasphere xenografts. Methylation RNA immunoprecipitation sequencing (MeRIP-seq) RNA sequencing was used to identify m6A-enriched transcripts in IDH1mut glioma. We show that IDH1mut production of D-2-HG is capable of reducing glioma cell growth via inhibition of the m6A epitranscriptomic regulator, FTO, with resultant m6A hypermethylation of a set of mRNA transcripts. On the basis of unbiased MeRIP-seq epitranscriptomic profiling, we identify ATF5 as a hypermethylated, downregulated transcript that potentially contributes to increased apoptosis. We further demonstrate how targeting this pathway genetically and pharmacologically reduces the proliferative potential of malignant IDH1wt gliomas, both in vitro and in vivo. Our work provides evidence that selective inhibition of the m6A epitranscriptomic regulator FTO attenuates growth in IDH1wt glioma, recapitulating the clinically favorable growth phenotype seen in the IDH1mut subtype. SIGNIFICANCE: We show that IDH1mut-generated D-2-HG can reduce glioma growth via inhibition of the m6A demethylase, FTO. FTO inhibition represents a potential therapeutic target for IDH1wt gliomas and possibly in conjunction with IDH1mut inhibitors for the treatment of IDH1mut glioma. Future studies are necessary to demonstrate the role of ATF5 downregulation in the indolent phenotype of IDH1mut gliomas, as well as to identify other involved gene transcripts deregulated by m6A hypermethylation.
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Adenina/análogos & derivados , Glioma , Glutaratos , Humanos , Animales , Ratones , Glioma/tratamiento farmacológico , ARN/metabolismo , ARN Mensajero/genética , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/genéticaRESUMEN
Significant evidence suggests that the failure of clinically tested epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (e.g. erlotinib, lapatinib, gefitinib) in glioblastoma (GBM) patients is primarily attributed to insufficient brain penetration, resulting in inadequate exposure to the targeted cells. Molecular imaging tools can facilitate GBM drug development by visualizing drug biodistribution and confirming target expression and localization. To assess brain exposure via PET molecular imaging, we synthesized fluorine-18 isotopologues of two brain-penetrant EGFR tyrosine kinase inhibitors developed specifically for GBM. Adapting our recently reported radiofluorination of N-arylsydnones, we constructed an ortho-disubstituted [18F]fluoroarene as the key intermediate. The radiotracers were produced on an automated synthesis module in 7-8% activity yield with high molar activity. In vivo PET imaging revealed rapid brain uptake in rodents and tumor accumulation in an EGFR-driven orthotopic GBM xenograft model.
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Glioblastoma (GBM), the most common primary malignant brain tumor, is a highly lethal form of cancer with a very limited set of treatment options. High heterogeneity in the tumor cell population and the invasive nature of these cells decrease the likely efficacy of traditional cancer treatments, thus requiring research into novel treatment options. The use of oncolytic viruses as potential therapeutics has been researched for some time. Zika virus (ZIKV) has demonstrated oncotropism and oncolytic effects on GBM stem cells (GSCs). To address the need for safe and effective GBM treatments, we designed an attenuated ZIKV strain (ZOL-1) that does not cause paralytic or neurological diseases in mouse models compared with unmodified ZIKV. Importantly, we found that patient-derived GBM tumors exhibited susceptibility (responders) and non-susceptibility (non-responders) to ZOL-1-mediated tumor cell killing, as evidenced by differential apoptotic cell death and cell viability upon ZOL-1 treatment. The oncolytic effect observed in responder cells was seen both in vitro in neurosphere models and in vivo upon xenograft. Finally, we observed that the use of ZOL-1 as combination therapy with multiple PI3K-AKT inhibitors in non-responder GBM resulted in enhanced chemotherapeutic efficacy. Altogether, this study establishes ZOL-1 as a safe and effective treatment against GBM and provides a foundation to conduct further studies evaluating its potential as an effective adjuvant with other chemotherapies and kinase inhibitors.
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Glioblastoma , Viroterapia Oncolítica , Infección por el Virus Zika , Virus Zika , Animales , Ratones , Humanos , Glioblastoma/metabolismo , Virus Zika/fisiología , Viroterapia Oncolítica/métodos , Fosfatidilinositol 3-QuinasasRESUMEN
Oxidative phosphorylation and glycolysis are the dominant ATP-generating pathways in mammalian metabolism. The balance between these two pathways is often shifted to execute cell-specific functions in response to stimuli that promote activation, proliferation, or differentiation. However, measurement of these metabolic switches has remained mostly qualitative, making it difficult to discriminate between healthy, physiological changes in energy transduction or compensatory responses due to metabolic dysfunction. We therefore present a broadly applicable method to calculate ATP production rates from oxidative phosphorylation and glycolysis using Seahorse XF Analyzer data and empirical conversion factors. We quantify the bioenergetic changes observed during macrophage polarization as well as cancer cell adaptation to in vitro culture conditions. Additionally, we detect substantive changes in ATP utilization upon neuronal depolarization and T cell receptor activation that are not evident from steady-state ATP measurements. This method generates a single readout that allows the direct comparison of ATP produced from oxidative phosphorylation and glycolysis in live cells. Additionally, the manuscript provides a framework for tailoring the calculations to specific cell systems or experimental conditions.
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Smegmamorpha , Animales , Smegmamorpha/metabolismo , Mitocondrias/metabolismo , Metabolismo Energético , Glucólisis , Fosforilación Oxidativa , Adenosina Trifosfato/metabolismo , Mamíferos/metabolismoRESUMEN
PURPOSE: Antiangiogenic therapies are known to cause high radiographic response rates due to reduction in vascular permeability resulting in a lower degree of contrast extravasation. In this study, we investigate the prognostic ability for model-derived parameters describing enhancing tumor volumetric dynamics to predict survival in recurrent glioblastoma treated with antiangiogenic therapy. EXPERIMENTAL DESIGN: N = 276 patients in two phase II trials were used as training data, including bevacizumab ± irinotecan (NCT00345163) and cabozantinib (NCT00704288), and N = 74 patients in the bevacizumab arm of a phase III trial (NCT02511405) were used for validation. Enhancing volumes were estimated using T1 subtraction maps, and a biexponential model was used to estimate regrowth (g) and regression (d) rates, time to tumor regrowth (TTG), and the depth of response (DpR). Response characteristics were compared to diffusion MR phenotypes previously shown to predict survival. RESULTS: Optimized thresholds occurred at g = 0.07 months-1 (phase II: HR = 0.2579, P = 5 × 10-20; phase III: HR = 0.2197, P = 5 × 10-5); d = 0.11 months-1 (HR = 0.3365, P < 0.0001; HR = 0.3675, P = 0.0113); TTG = 3.8 months (HR = 0.2702, P = 6 × 10-17; HR = 0.2061, P = 2 × 10-5); and DpR = 11.3% (HR = 0.6326, P = 0.0028; HR = 0.4785, P = 0.0206). Multivariable Cox regression controlling for age and baseline tumor volume confirmed these factors as significant predictors of survival. Patients with a favorable pretreatment diffusion MRI phenotype had a significantly longer TTG and slower regrowth. CONCLUSIONS: Recurrent glioblastoma patients with a large, durable radiographic response to antiangiogenic agents have significantly longer survival. This information is useful for interpreting activity of antiangiogenic agents in recurrent glioblastoma.
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Neoplasias Encefálicas , Glioblastoma , Humanos , Glioblastoma/diagnóstico por imagen , Glioblastoma/tratamiento farmacológico , Bevacizumab/uso terapéutico , Inhibidores de la Angiogénesis/uso terapéutico , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/tratamiento farmacológico , Recurrencia Local de Neoplasia/diagnóstico por imagen , Recurrencia Local de Neoplasia/tratamiento farmacológico , Irinotecán/uso terapéutico , Imagen por Resonancia Magnética/métodosRESUMEN
Glioblastoma (GBM) represents the most aggressive subtype of glioma, noted for its profound invasiveness and molecular heterogeneity. The mesenchymal (MES) transcriptomic subtype is frequently associated with therapy resistance, rapid recurrence, and increased tumor-associated macrophages. Notably, activation of the NF-κB pathway and alterations in the PTEN gene are both associated with this malignant transition. Although PTEN aberrations have been shown to be associated with enhanced NF-κB signaling, the relationships between PTEN, NF-κB and MES transition are poorly understood in GBM. Here, we show that PTEN regulates the chromatin binding of bromodomain and extraterminal (BET) family proteins, BRD2 and BRD4, mediated by p65/RelA localization to the chromatin. By utilizing patient-derived glioblastoma stem cells and CRISPR gene editing of the RELA gene, we demonstrate a crucial role for RelA lysine 310 acetylation in recruiting BET proteins to chromatin for MES gene expression and GBM cell invasion upon PTEN loss. Remarkably, we found that BRD2 is dependent on chromatin associated acetylated RelA for its recruitment to MES gene promoters and their expression. Furthermore, loss of BRD2 results in the loss of MES signature, accompanied by an enrichment of proneural signature and enhanced therapy responsiveness. Finally, we demonstrate that disrupting the NFκB/BRD2 interaction with a brain penetrant BET-BD2 inhibitor reduces mesenchymal gene expression, GBM invasion, and therapy resistance in GBM models. This study uncovers the role of hitherto unexplored PTEN-NF-κB-BRD2 pathway in promoting MES transition and suggests inhibiting this complex with BET-BD2 specific inhibitors as a therapeutic approach to target the MES phenotype in GBM.
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PURPOSE: There is limited knowledge about the associations between sodium and proton MRI measurements in brain tumors. The purpose of this study was to quantify intra- and intertumoral correlations between sodium, diffusion, and perfusion MRI in human gliomas. METHODS: Twenty glioma patients were prospectively studied on a 3T MRI system with multinuclear capabilities. Three mutually exclusive tumor volumes of interest (VOIs) were segmented: contrast-enhancing tumor (CET), T2/FLAIR hyperintense non-enhancing tumor (NET), and necrosis. Median and voxel-wise associations between apparent diffusion coefficient (ADC), normalized relative cerebral blood volume (nrCBV), and normalized sodium measurements were quantified for each VOI. RESULTS: Both relative sodium concentration and ADC were significantly higher in areas of necrosis compared to NET (P = 0.003 and P = 0.008, respectively) and CET (P = 0.02 and P = 0.02). Sodium concentration was higher in CET compared to NET (P = 0.04). Sodium and ADC were higher in treated compared to treatment-naïve gliomas within NET (P = 0.006 and P = 0.01, respectively), and ADC was elevated in CET (P = 0.03). Median ADC and sodium concentration were positively correlated across patients in NET (r = 0.77, P < 0.0001) and CET (r = 0.84, P < 0.0001), but not in areas of necrosis (r = 0.45, P = 0.12). Median nrCBV and sodium concentration were negatively correlated across patients in areas of NET (r=-0.63, P = 0.003). Similar associations were observed when examining voxel-wise correlations within VOIs. CONCLUSION: Sodium MRI is positively correlated with proton diffusion MRI measurements in gliomas, likely reflecting extracellular water. Unique areas of multinuclear MRI contrast may be useful in future studies to understand the chemistry of the tumor microenvironment.
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Neoplasias Encefálicas , Glioma , Humanos , Protones , Imagen por Resonancia Magnética , Glioma/diagnóstico por imagen , Glioma/patología , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/patología , Imagen de Difusión por Resonancia Magnética , Perfusión , Necrosis , Microambiente TumoralRESUMEN
BACKGROUND: Resistance to existing therapies is a significant challenge in improving outcomes for glioblastoma (GBM) patients. Metabolic plasticity has emerged as an important contributor to therapy resistance, including radiation therapy (RT). Here, we investigated how GBM cells reprogram their glucose metabolism in response to RT to promote radiation resistance. METHODS: Effects of radiation on glucose metabolism of human GBM specimens were examined in vitro and in vivo with the use of metabolic and enzymatic assays, targeted metabolomics, and FDG-PET. Radiosensitization potential of interfering with M2 isoform of pyruvate kinase (PKM2) activity was tested via gliomasphere formation assays and in vivo human GBM models. RESULTS: Here, we show that RT induces increased glucose utilization by GBM cells, and this is accompanied with translocation of GLUT3 transporters to the cell membrane. Irradiated GBM cells route glucose carbons through the pentose phosphate pathway (PPP) to harness the antioxidant power of the PPP and support survival after radiation. This response is regulated in part by the PKM2. Activators of PKM2 can antagonize the radiation-induced rewiring of glucose metabolism and radiosensitize GBM cells in vitro and in vivo. CONCLUSIONS: These findings open the possibility that interventions designed to target cancer-specific regulators of metabolic plasticity, such as PKM2, rather than specific metabolic pathways, have the potential to improve the radiotherapeutic outcomes in GBM patients.
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Glioblastoma , Piruvato Quinasa , Humanos , Piruvato Quinasa/metabolismo , Glioblastoma/metabolismo , Antioxidantes , Isoformas de Proteínas , Glucosa/metabolismo , Línea Celular TumoralRESUMEN
Malignant tumors exhibit heterogeneous metabolic reprogramming, hindering the identification of translatable vulnerabilities for metabolism-targeted therapy. How molecular alterations in tumors promote metabolic diversity and distinct targetable dependencies remains poorly defined. Here we create a resource consisting of lipidomic, transcriptomic, and genomic data from 156 molecularly diverse glioblastoma (GBM) tumors and derivative models. Through integrated analysis of the GBM lipidome with molecular datasets, we identify CDKN2A deletion remodels the GBM lipidome, notably redistributing oxidizable polyunsaturated fatty acids into distinct lipid compartments. Consequently, CDKN2A-deleted GBMs display higher lipid peroxidation, selectively priming tumors for ferroptosis. Together, this study presents a molecular and lipidomic resource of clinical and preclinical GBM specimens, which we leverage to detect a therapeutically exploitable link between a recurring molecular lesion and altered lipid metabolism in GBM.
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Ferroptosis , Glioblastoma , Metabolismo de los Lípidos , Humanos , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Ferroptosis/genética , Ferroptosis/fisiología , Perfilación de la Expresión Génica , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/patología , Metabolismo de los Lípidos/genética , Metabolismo de los Lípidos/fisiología , Recurrencia Local de NeoplasiaRESUMEN
Amine-weighted chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is particularly valuable as an amine- and pH-sensitive imaging technique in brain tumors, targeting the intrinsically high concentration of amino acids with exchangeable amine protons and reduced extracellular pH in brain tumors. Amine-weighted CEST MRI contrast is dependent on the glioma genotype, likely related to differences in degree of malignancy and metabolic behavior. Amine-weighted CEST MRI may provide complementary value to anatomic imaging in conventional and exploratory therapies in brain tumors, including chemoradiation, antiangiogenic therapies, and immunotherapies. Continual improvement and clinical testing of amine-weighted CEST MRI has the potential to greatly impact patients with brain tumors by understanding vulnerabilities in the tumor microenvironment that may be therapeutically exploited.
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Aminas , Neoplasias Encefálicas , Humanos , Aminas/química , Concentración de Iones de Hidrógeno , Imagen por Resonancia Magnética/métodos , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/química , Protones , Microambiente TumoralRESUMEN
Multiple sclerosis (MS) is an autoimmune disease driven by lymphocyte activation against myelin autoantigens in the central nervous system leading to demyelination and neurodegeneration. The deoxyribonucleoside salvage pathway with the rate-limiting enzyme deoxycytidine kinase (dCK) captures extracellular deoxyribonucleosides for use in intracellular deoxyribonucleotide metabolism. Previous studies have shown that deoxyribonucleoside salvage activity is enriched in lymphocytes and required for early lymphocyte development. However, specific roles for the deoxyribonucleoside salvage pathway and dCK in autoimmune diseases such as MS are unknown. Here we demonstrate that dCK activity is necessary for the development of clinical symptoms in the MOG35-55 and MOG1-125 experimental autoimmune encephalomyelitis (EAE) mouse models of MS. During EAE disease, deoxyribonucleoside salvage activity is elevated in the spleen and lymph nodes. Targeting dCK with the small molecule dCK inhibitor TRE-515 limits disease severity when treatments are started at disease induction or when symptoms first appear. EAE mice treated with TRE-515 have significantly fewer infiltrating leukocytes in the spinal cord, and TRE-515 blocks activation-induced B and T cell proliferation and MOG35-55 -specific T cell expansion without affecting innate immune cells or naïve T and B cell populations. Our results demonstrate that targeting dCK limits symptoms in EAE mice and suggest that dCK activity is required for MOG35-55 -specific lymphocyte activation-induced proliferation.
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Encefalomielitis Autoinmune Experimental , Esclerosis Múltiple , Animales , Ratones , Desoxicitidina Quinasa/genética , Linfocitos/metabolismo , Modelos Animales de Enfermedad , Ratones Endogámicos C57BLRESUMEN
Analysis of tumor gene expression is an important approach for the classification and identification of therapeutic vulnerabilities. However, targeting glioblastoma (GBM) based on molecular subtyping has not yet translated into successful therapies. Here, we present an integrative approach based on molecular pathways to expose new potentially actionable targets. We used gene set enrichment analysis (GSEA) to conduct an unsupervised clustering analysis to condense the gene expression data from bulk patient samples and patient-derived gliomasphere lines into new gene signatures. We identified key targets that are predicted to be differentially activated between tumors and were functionally validated in a library of gliomasphere cultures. Resultant cluster-specific gene signatures associated not only with hallmarks of cell cycle and stemness gene expression, but also with cell-type specific markers and different cellular states of GBM. Several upstream regulators, such as PIK3R1 and EBF1 were differentially enriched in cells bearing stem cell like signatures and bear further investigation. We identified the transcription factor E2F1 as a key regulator of tumor cell proliferation and self-renewal in only a subset of gliomasphere cultures predicted to be E2F1 signaling dependent. Our in vivo work also validated the functional significance of E2F1 in tumor formation capacity in the predicted samples. E2F1 inhibition also differentially sensitized E2F1-dependent gliomasphere cultures to radiation treatment. Our findings indicate that this novel approach exploring cancer pathways highlights key therapeutic vulnerabilities for targeting GBM.
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Glioblastoma , Humanos , Glioblastoma/tratamiento farmacológico , Línea Celular Tumoral , Factores de Transcripción/metabolismo , Proliferación Celular/genética , Factor de Transcripción E2F1/genéticaRESUMEN
Cancer cells need a steady supply of nutrients to evade cell death and proliferate. Depriving cancer cells of the amino acid cystine can trigger the non-apoptotic cell death process of ferroptosis. Here, we report that cancer cells can evade cystine deprivation-induced ferroptosis by uptake and catabolism of the cysteine-rich extracellular protein albumin. This protective mechanism is enhanced by mTORC1 inhibition and involves albumin degradation in the lysosome, predominantly by cathepsin B (CTSB). CTSB-dependent albumin breakdown followed by export of cystine from the lysosome via the transporter cystinosin fuels the synthesis of glutathione, which suppresses lethal lipid peroxidation. When cancer cells are grown under non-adherent conditions as spheroids, mTORC1 pathway activity is reduced, and albumin supplementation alone affords considerable protection against ferroptosis. These results identify the catabolism of extracellular protein within the lysosome as a mechanism that can inhibit ferroptosis in cancer cells.
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Ferroptosis , Cistina , Glutatión/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina , Lisosomas/metabolismo , Albúminas , Línea Celular TumoralRESUMEN
The Lazarus effect is a rare condition that happens when someone seemingly dead shows signs of life. The epidermal growth factor receptor (EGFR) represents a target in the fatal neoplasm glioblastoma (GBM) that through a series of negative clinical trials has prompted a vocal subset of the neuro-oncology community to declare this target dead. However, an argument can be made that the core tenets of precision oncology were overlooked in the initial clinical enthusiasm over EGFR as a therapeutic target in GBM. Namely, the wrong drugs were tested on the wrong patients at the wrong time. Furthermore, new insights into the biology of EGFR in GBM vis-à-vis other EGFR-driven neoplasms, such as non-small cell lung cancer, and development of novel GBM-specific EGFR therapeutics resurrects this target for future studies. Here, we will examine the distinct EGFR biology in GBM, how it exacerbates the challenge of treating a CNS neoplasm, how these unique challenges have influenced past and present EGFR-targeted therapeutic design and clinical trials, and what adjustments are needed to therapeutically exploit EGFR in this devastating disease.
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Neoplasias Encefálicas , Carcinoma de Pulmón de Células no Pequeñas , Glioblastoma , Neoplasias Pulmonares , Humanos , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/metabolismo , Receptores ErbB/metabolismo , Glioblastoma/metabolismo , Medicina de PrecisiónRESUMEN
Natural killer (NK) cells are innate lymphocytes that possess traits of adaptive immunity, such as memory formation. However, the molecular mechanisms by which NK cells persist to form memory cells are not well understood. Using single-cell RNA sequencing, we identified two distinct effector NK cell (NKeff) populations following mouse cytomegalovirus infection. Ly6C- memory precursor (MP) NK cells showed enhanced survival during the contraction phase in a Bcl2-dependent manner, and differentiated into Ly6C+ memory NK cells. MP NK cells exhibited distinct transcriptional and epigenetic signatures compared with Ly6C+ NKeff cells, with a core epigenetic signature shared with MP CD8+ T cells enriched in ETS1 and Fli1 DNA-binding motifs. Fli1 was induced by STAT5 signaling ex vivo, and increased levels of the pro-apoptotic factor Bim in early effector NK cells following viral infection. These results suggest that a NK cell-intrinsic checkpoint controlled by the transcription factor Fli1 limits MP NK formation by regulating early effector NK cell fitness during viral infection.
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Infecciones por Citomegalovirus , Muromegalovirus , Inmunidad Adaptativa , Animales , Linfocitos T CD8-positivos , Memoria Inmunológica , Células Asesinas Naturales , RatonesRESUMEN
PURPOSE: To quantify abnormal metabolism of diffuse gliomas using "aerobic glycolytic imaging" and investigate its biological correlation. METHODS: All subjects underwent a pH-weighted amine chemical exchange saturation transfer spin-and-gradient-echo echoplanar imaging (CEST-SAGE-EPI) and dynamic susceptibility contrast perfusion MRI. Relative oxygen extraction fraction (rOEF) was estimated as the ratio of reversible transverse relaxation rate R2' to normalized relative cerebral blood volume. An aerobic glycolytic index (AGI) was derived by the ratio of pH-weighted image contrast (MTRasym at 3.0 ppm) to rOEF. AGI was compared between different tumor types (N = 51, 30 IDH mutant and 21 IDH wild type). Metabolic MR parameters were correlated with 18F-FDG uptake (N = 8, IDH wild-type glioblastoma), expression of key glycolytic proteins using immunohistochemistry (N = 38 samples, 21 from IDH mutant and 17 from IDH wild type), and bioenergetics analysis on purified tumor cells (N = 7, IDH wild-type high grade). RESULTS: AGI was significantly lower in IDH mutant than wild-type gliomas (0.48 ± 0.48 vs. 0.70 ± 0.48; P = 0.03). AGI was strongly correlated with 18F-FDG uptake both in non-enhancing tumor (Spearman, ρ = 0.81; P = 0.01) and enhancing tumor (ρ = 0.81; P = 0.01). AGI was significantly correlated with glucose transporter 3 (ρ = 0.71; P = 0.004) and hexokinase 2 (ρ = 0.73; P = 0.003) in IDH wild-type glioma, and monocarboxylate transporter 1 (ρ = 0.59; P = 0.009) in IDH mutant glioma. Additionally, a significant correlation was found between AGI derived from bioenergetics analysis and that estimated from MRI (ρ = 0.79; P = 0.04). CONCLUSION: AGI derived from molecular MRI was correlated with glucose uptake (18F-FDG and glucose transporter 3/hexokinase 2) and cellular AGI in IDH wild-type gliomas, whereas AGI in IDH mutant gliomas appeared associated with monocarboxylate transporter density.