RESUMEN
Tumor adaptation or selection is thought to underlie therapy resistance in glioma. To investigate longitudinal epigenetic evolution of gliomas in response to therapeutic pressure, we performed an epigenomic analysis of 132 matched initial and recurrent tumors from patients with IDH-wildtype (IDHwt) and IDH-mutant (IDHmut) glioma. IDHwt gliomas showed a stable epigenome over time with relatively low levels of global methylation. The epigenome of IDHmut gliomas showed initial high levels of genome-wide DNA methylation that was progressively reduced to levels similar to those of IDHwt tumors. Integration of epigenomics, gene expression, and functional genomics identified HOXD13 as a master regulator of IDHmut astrocytoma evolution. Furthermore, relapse of IDHmut tumors was accompanied by histologic progression that was associated with survival, as validated in an independent cohort. Finally, the initial cell composition of the tumor microenvironment varied between IDHwt and IDHmut tumors and changed differentially following treatment, suggesting increased neoangiogenesis and T-cell infiltration upon treatment of IDHmut gliomas. This study provides one of the largest cohorts of paired longitudinal glioma samples with epigenomic, transcriptomic, and genomic profiling and suggests that treatment of IDHmut glioma is associated with epigenomic evolution toward an IDHwt-like phenotype. SIGNIFICANCE: Standard treatments are related to loss of DNA methylation in IDHmut glioma, resulting in epigenetic activation of genes associated with tumor progression and alterations in the microenvironment that resemble treatment-naïve IDHwt glioma.
Asunto(s)
Neoplasias Encefálicas , Glioma , Isocitrato Deshidrogenasa , Humanos , Neoplasias Encefálicas/patología , Epigénesis Genética , Epigenómica , Glioma/patología , Isocitrato Deshidrogenasa/genética , Isocitrato Deshidrogenasa/metabolismo , Mutación , Recurrencia Local de Neoplasia/genética , Microambiente TumoralRESUMEN
Recurrence of meningiomas is unpredictable by current invasive methods based on surgically removed specimens. Identification of patients likely to recur using noninvasive approaches could inform treatment strategy, whether intervention or monitoring. In this study, we analyze the DNA methylation levels in blood (serum and plasma) and tissue samples from 155 meningioma patients, compared to other central nervous system tumor and non-tumor entities. We discover DNA methylation markers unique to meningiomas and use artificial intelligence to create accurate and universal models for identifying and predicting meningioma recurrence, using either blood or tissue samples. Here we show that liquid biopsy is a potential noninvasive and reliable tool for diagnosing and predicting outcomes in meningioma patients. This approach can improve personalized management strategies for these patients.
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Neoplasias Meníngeas , Meningioma , Humanos , Meningioma/diagnóstico , Meningioma/genética , Pronóstico , Inteligencia Artificial , Metilación de ADN , Biopsia Líquida , Neoplasias Meníngeas/diagnóstico , Neoplasias Meníngeas/genéticaRESUMEN
Distinguishing tumor progression from radiation necrosis after treatment in patients with brain tumors presents a clinical dilemma. A well-characterized, orthotopic rodent model of radiation-induced brain necrosis including a tumor is not currently available The objective of the study was to create focal radiation necrosis in rat brain bearing human glioblastoma (GBM) using stereotactic radiosurgery and confirm it by immuno-histological analysis. Nude rats implanted with primary GBM cells were irradiated using a stereotactic setup (n = 3) or received no radiation (n = 3). Ten weeks after the implantation, growth of the tumor was confirmed by magnetic resonance imaging (MRI). For each animal, MRI and contrast-enhanced CT images were obtained and fused using registration software. The tumor was identified and delineated using the fused CT/MR images. A treatment plan was generated using a 4 mm radiosurgery cone such that one portion of the tumor receives 100% dose of 60 Gy sufficient to cause necrosis, whereas the tumor edge at depth receives only 50% or less dose, allowing for regrowth of the tumor. The brains were collected 10 weeks after irradiation and immuno-histological analysis was performed. Hematoxylin and eosin staining showed central liquefaction necrosis in the high dose region consistent with necrosis and viable tumor in the peripheral low dose region. Ki-67 staining showed highly proliferative tumor cells surrounding the necrotic parts of the tumor. Luxol fast blue and lectin staining showed demyelination and vascular injury in brain tissue consistent with radiation necrosis. We have developed a novel model of radiation necrosis in rats bearing glioma.
Asunto(s)
Neoplasias Encefálicas/diagnóstico , Modelos Animales de Enfermedad , Glioblastoma/diagnóstico , Recurrencia Local de Neoplasia/diagnóstico , Complicaciones Posoperatorias , Traumatismos por Radiación/diagnóstico , Radiocirugia/efectos adversos , Animales , Encéfalo/patología , Encéfalo/efectos de la radiación , Neoplasias Encefálicas/cirugía , Diagnóstico Diferencial , Glioblastoma/cirugía , Humanos , Técnicas para Inmunoenzimas , Imagen por Resonancia Magnética , Masculino , Necrosis , Recurrencia Local de Neoplasia/cirugía , Pronóstico , Traumatismos por Radiación/etiología , Traumatismos por Radiación/patología , Ratas , Ratas Desnudas , Células Tumorales CultivadasRESUMEN
Glioblastoma is one of the most aggressive types of cancer with success of therapy being hampered by the existence of treatment resistant populations of stem-like Tumour Initiating Cells (TICs) and poor blood-brain barrier drug penetration. Therapies capable of effectively targeting the TIC population are in high demand. Here, we synthesize spherical diketopyrrolopyrrole-based Conjugated Polymer Nanoparticles (CPNs) with an average diameter of 109 nm. CPNs were designed to include fluorescein-conjugated Hyaluronic Acid (HA), a ligand for the CD44 receptor present on one population of TICs. We demonstrate blood-brain barrier permeability of this system and concentration and cell cycle phase-dependent selective uptake of HA-CPNs in CD44 positive GBM-patient derived cultures. Interestingly, we found that uptake alone regulated the levels and signaling activity of the CD44 receptor, decreasing stemness, invasive properties and proliferation of the CD44-TIC populations in vitro and in a patient-derived xenograft zebrafish model. This work proposes a novel, CPN- based, and surface moiety-driven selective way of targeting of TIC populations in brain cancer.
Asunto(s)
Glioblastoma , Nanopartículas , Animales , Línea Celular Tumoral , Proliferación Celular , Glioblastoma/patología , Humanos , Receptores de Hialuranos/metabolismo , Ácido Hialurónico/farmacología , Polímeros/farmacología , Pez Cebra/metabolismoRESUMEN
BACKGROUND: DNA methylation abnormalities are pervasive in pituitary neuroendocrine tumors (PitNETs). The feasibility to detect methylome alterations in circulating cell-free DNA (cfDNA) has been reported for several central nervous system (CNS) tumors but not across PitNETs. The aim of the study was to use the liquid biopsy (LB) approach to detect PitNET-specific methylation signatures to differentiate these tumors from other sellar diseases. METHODS: We profiled the cfDNA methylome (EPIC array) of 59 serum and 41 plasma LB specimens from patients with PitNETs and other CNS diseases (sellar tumors and other pituitary non-neoplastic diseases, lower-grade gliomas, and skull-base meningiomas) or nontumor conditions, grouped as non-PitNET. RESULTS: Our results indicated that despite quantitative and qualitative differences between serum and plasma cfDNA composition, both sources of LB showed that patients with PitNETs presented a distinct methylome landscape compared to non-PitNETs. In addition, LB methylomes captured epigenetic features reported in PitNET tissue and provided information about cell-type composition. Using LB-derived PitNETs-specific signatures as input to develop machine-learning predictive models, we generated scores that distinguished PitNETs from non-PitNETs conditions, including sellar tumor and non-neoplastic pituitary diseases, with accuracies above ~93% in independent cohort sets. CONCLUSIONS: Our results underpin the potential application of methylation-based LB profiling as a noninvasive approach to identify clinically relevant epigenetic markers to diagnose and potentially impact the prognostication and management of patients with PitNETs.
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Ácidos Nucleicos Libres de Células , Tumores Neuroendocrinos , Neoplasias Hipofisarias , Biomarcadores de Tumor/genética , Metilación de ADN , Humanos , Tumores Neuroendocrinos/diagnóstico , Tumores Neuroendocrinos/genética , Tumores Neuroendocrinos/patología , Neoplasias Hipofisarias/diagnóstico , Neoplasias Hipofisarias/genética , Neoplasias Hipofisarias/patologíaRESUMEN
Cancer stem cells (CSCs) are characterized by their self-renewing potential and by their ability to differentiate and phenocopy the original tumor in orthotopic xenografts. Long-term propagation of glioblastoma (GBM) cells in serum-containing medium results in loss of the CSCs and outgrowth of cells genetically and biologically divergent from the parental tumors. In contrast, the use of a neurosphere assay, a serum-free culture for selection, and propagation of central nervous system-derived stem cells allows the selection of a subpopulation containing CSCs. Gliosarcoma (GS), a morphological variant comprising approximately 2% of GBMs, present a biphasic growth pattern, composed of glial and metaplastic mesenchymal components. To assess whether the neurosphere assay would allow the amplification of a subpopulation of cells with "gliosarcoma stem cell" properties, capable of propagating both components of this malignancy, we have generated neurospheres and serum cultures from primary GS and GBM surgical specimens. Neurosphere cultures from GBM and GS samples expressed neural stem cell markers Sox2, Musashi1, and Nestin. In contrast to the GBM neurosphere lines, the GS neurospheres were negative for the stem cell marker CD133. All neurosphere lines generated high-grade invasive orthotopic tumor xenografts, with histological features strikingly similar to the parental tumors, demonstrating that these cultures indeed are enriched in CSCs. Remarkably, low-passage GS serum cultures retained the expression of stem cell markers, the ability to form neurospheres, and tumorigenicity. The GS experimental tumors phenocopied the parental tumor, exhibiting biphasic glial and mesenchymal components, constituting a clinically relevant model to investigate mesenchymal differentiation in GBMs.
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Diferenciación Celular/fisiología , Glioblastoma/patología , Gliosarcoma/patología , Células Madre Mesenquimatosas/fisiología , Células Madre Neoplásicas/citología , Antígeno AC133 , Animales , Antígenos CD/metabolismo , Western Blotting , Diferenciación Celular/genética , Glioblastoma/metabolismo , Gliosarcoma/metabolismo , Glicoproteínas/metabolismo , Humanos , Inmunohistoquímica , Técnicas In Vitro , Proteínas de Filamentos Intermediarios/metabolismo , Imagen por Resonancia Magnética , Células Madre Mesenquimatosas/citología , Células Madre Neoplásicas/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Nestina , Péptidos/metabolismo , Proteínas de Unión al ARN/metabolismo , Ratas , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Transcripción SOXB1/metabolismo , Trasplante Heterólogo , Células Tumorales CultivadasRESUMEN
Models of human cancer, to be useful, must replicate human disease with high fidelity. Our focus in this study is rat xenograft brain tumors as a model of human embedded cerebral tumors. A distinguishing signature of such tumors in humans, that of contrast-enhancement on imaging, is often not present when the human cells grow in rodents, despite the xenografts having nearly identical DNA signatures to the original tumor specimen. Although contrast enhancement was uniformly evident in all the human tumors from which the xenografts' cells were derived, we show that long-term contrast enhancement in the model tumors may be determined conditionally by the tumor microenvironment at the time of cell implantation. We demonstrate this phenomenon in one of two patient-derived orthotopic xenograft (PDOX) models using cancer stem-like cell (CSC)-enriched neurospheres from human tumor resection specimens, transplanted to groups of immune-compromised rats in the presence or absence of a collagen/fibrin scaffolding matrix, Matrigel. The rats were imaged by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and their brains were examined by histopathology. Targeted proteomics of the PDOX tumor specimens grown from CSC implanted with and without Matrigel showed that while the levels of the majority of proteins and post-translational modifications were comparable between contrast-enhancing and non-enhancing tumors, phosphorylation of Fox038 showed a differential expression. The results suggest key proteins determine contrast enhancement and suggest a path toward the development of better animal models of human glioma. Future work is needed to elucidate fully the molecular determinants of contrast-enhancement.
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Neoplasias Encefálicas/diagnóstico , Encéfalo/diagnóstico por imagen , Colágeno/administración & dosificación , Glioblastoma/diagnóstico , Laminina/administración & dosificación , Proteoglicanos/administración & dosificación , Microambiente Tumoral , Animales , Encéfalo/patología , Neoplasias Encefálicas/patología , Combinación de Medicamentos , Femenino , Glioblastoma/patología , Humanos , Imagen por Resonancia Magnética , Células Madre Neoplásicas/patología , Ratas , Esferoides Celulares , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto/métodosRESUMEN
Homozygous deletion of methylthioadenosine phosphorylase (MTAP) in cancers such as glioblastoma represents a potentially targetable vulnerability. Homozygous MTAP-deleted cell lines in culture show elevation of MTAP's substrate metabolite, methylthioadenosine (MTA). High levels of MTA inhibit protein arginine methyltransferase 5 (PRMT5), which sensitizes MTAP-deleted cells to PRMT5 and methionine adenosyltransferase 2A (MAT2A) inhibition. While this concept has been extensively corroborated in vitro, the clinical relevance relies on exhibiting significant MTA accumulation in human glioblastoma. In this work, using comprehensive metabolomic profiling, we show that MTA secreted by MTAP-deleted cells in vitro results in high levels of extracellular MTA. We further demonstrate that homozygous MTAP-deleted primary glioblastoma tumors do not significantly accumulate MTA in vivo due to metabolism of MTA by MTAP-expressing stroma. These findings highlight metabolic discrepancies between in vitro models and primary human tumors that must be considered when developing strategies for precision therapies targeting glioblastoma with homozygous MTAP deletion.
Asunto(s)
Neoplasias Encefálicas/genética , Encéfalo/patología , Desoxiadenosinas/metabolismo , Glioblastoma/genética , Purina-Nucleósido Fosforilasa/deficiencia , Tionucleósidos/metabolismo , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Encéfalo/efectos de los fármacos , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Medios de Cultivo Condicionados/metabolismo , Desoxiadenosinas/análisis , Femenino , Secciones por Congelación , Glioblastoma/tratamiento farmacológico , Glioblastoma/patología , Homocigoto , Humanos , Metabolómica , Metionina Adenosiltransferasa/metabolismo , Terapia Molecular Dirigida/métodos , Medicina de Precisión/métodos , Proteína-Arginina N-Metiltransferasas/metabolismo , Purina-Nucleósido Fosforilasa/genética , Eliminación de Secuencia , Tionucleósidos/análisis , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Extrachromosomal, circular DNA (ecDNA) is emerging as a prevalent yet less characterized oncogenic alteration in cancer genomes. We leverage ChIA-PET and ChIA-Drop chromatin interaction assays to characterize genome-wide ecDNA-mediated chromatin contacts that impact transcriptional programs in cancers. ecDNAs in glioblastoma patient-derived neurosphere and prostate cancer cell cultures are marked by widespread intra-ecDNA and genome-wide chromosomal interactions. ecDNA-chromatin contact foci are characterized by broad and high-level H3K27ac signals converging predominantly on chromosomal genes of increased expression levels. Prostate cancer cells harboring synthetic ecDNA circles composed of characterized enhancers result in the genome-wide activation of chromosomal gene transcription. Deciphering the chromosomal targets of ecDNAs at single-molecule resolution reveals an association with actively expressed oncogenes spatially clustered within ecDNA-directed interaction networks. Our results suggest that ecDNA can function as mobile transcriptional enhancers to promote tumor progression and manifest a potential synthetic aneuploidy mechanism of transcription control in cancer.
Asunto(s)
Cromosomas/genética , ADN de Neoplasias/genética , Glioblastoma/genética , Oncogenes/genética , Carcinogénesis/genética , Cromatina/genética , HumanosRESUMEN
BACKGROUND: The detection of somatic mutations in cell-free DNA (cfDNA) from liquid biopsy has emerged as a noninvasive tool to monitor the follow-up of cancer patients. However, the significance of cfDNA clinical utility remains uncertain in patients with brain tumors, primarily because of the limited sensitivity cfDNA has to detect real tumor-specific somatic mutations. This unresolved challenge has prevented accurate follow-up of glioma patients with noninvasive approaches. METHODS: Genome-wide DNA methylation profiling of tumor tissue and serum cfDNA of glioma patients. RESULTS: Here, we developed a noninvasive approach to profile the DNA methylation status in the serum of patients with gliomas and identified a cfDNA-derived methylation signature that is associated with the presence of gliomas and related immune features. By testing the signature in an independent discovery and validation cohorts, we developed and verified a score metric (the "glioma-epigenetic liquid biopsy score" or GeLB) that optimally distinguished patients with or without glioma (sensitivity: 100%, specificity: 97.78%). Furthermore, we found that changes in GeLB score reflected clinicopathological changes during surveillance (eg, progression, pseudoprogression, and response to standard or experimental treatment). CONCLUSIONS: Our results suggest that the GeLB score can be used as a complementary approach to diagnose and follow up patients with glioma.
Asunto(s)
Neoplasias Encefálicas , Glioma , Biomarcadores de Tumor/genética , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/genética , Metilación de ADN , Epigenómica , Glioma/diagnóstico , Glioma/genética , Humanos , Biopsia LíquidaRESUMEN
BACKGROUND: Distinct genome-wide methylation patterns cluster pituitary neuroendocrine tumors (PitNETs) into molecular groups associated with specific clinicopathological features. Here we aim to identify, characterize, and validate methylation signatures that objectively classify PitNET into clinicopathological groups. METHODS: Combining in-house and publicly available data, we conducted an analysis of the methylome profile of a comprehensive cohort of 177 tumors (Panpit cohort) and 20 nontumor specimens from the pituitary gland. We also retrieved methylome data from an independent PitNET cohort (N = 86) to validate our findings. RESULTS: We identified three methylation clusters associated with adenohypophyseal cell lineages and functional status using an unsupervised approach. Differentially methylated probes (DMP) significantly distinguished the Panpit clusters and accurately assigned the samples of the validation cohort to their corresponding lineage and functional subtypes memberships. The DMPs were annotated in regulatory regions enriched with enhancer elements, associated with pathways and genes involved in pituitary cell identity, function, tumorigenesis, and invasiveness. Some DMPs correlated with genes with prognostic and therapeutic values in other intra- or extracranial tumors. CONCLUSIONS: We identified and validated methylation signatures, mainly annotated in enhancer regions that distinguished PitNETs by distinct adenohypophyseal cell lineages and functional status. These signatures provide the groundwork to develop an unbiased approach to classifying PitNETs according to the most recent classification recommended by the 2017 WHO and to explore their biological and clinical relevance in these tumors.
Asunto(s)
Tumores Neuroendocrinos , Neoplasias Hipofisarias , Estudios de Cohortes , Metilación de ADN , Humanos , Tumores Neuroendocrinos/genética , Neoplasias Hipofisarias/genética , PronósticoRESUMEN
There is a compelling need for new therapeutic strategies for glioblastoma multiforme (GBM). Preclinical target and therapeutic discovery for GBMs is primarily conducted using cell lines grown in serum-containing media, such as U-87 MG, which do not reflect the gene expression profiles of tumors found in GBM patients. To address this lack of representative models, we sought to develop a panel of patient-derived GBM models and characterize their genomic features, using RNA sequencing (RNA-seq) and growth characteristics, both when grown as neurospheres in culture, and grown orthotopically as xenografts in mice. When we compared these with commonly used GBM cell lines in the Cancer Cell Line Encyclopedia (CCLE), we found these patient-derived models to have greater diversity in gene expression and to better correspond to GBMs directly sequenced from patient tumor samples. We also evaluated the potential of these models for targeted therapy, by using the genomic characterization to identify small molecules that inhibit the growth of distinct subsets of GBMs, paving the way for precision medicines for GBM.
RESUMEN
Marked progress has been made recently in the treatment of patients with central nervous system (CNS) tumors, especially gliomas. However, because of the relative rarity of these tumors compared with other malignancies, advances in the molecular/genetic analysis leading to future targeted treatments rely on systematic, organized tissue banking. Several large multi-institutional efforts have utilized major tissue banks that have yielded valuable information that may lead to a better understanding of the pathogenesis of CNS tumors. This manuscript portrays best practices for the establishment and maintenance of a well-organized CNS tumor bank. In addition, annotation for clinical and research needs is explained. The potential benefits to clinical care, as well as basic science and translational research are also described.
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Medicina de Precisión/métodos , Bancos de Tejidos/tendencias , Encéfalo , Neoplasias Encefálicas , Neoplasias del Sistema Nervioso Central , Glioma , Humanos , Medicina de Precisión/tendencias , Investigación Biomédica TraslacionalRESUMEN
Introduction of polymeric nanoparticles in cancer therapeutics is widely investigated since nanomedicine often enables the intratumoral delivery of drugs with increased efficacy with minimal side effects. In this study MRI monitoring was employed to study the therapeutic effect of nanocombretastatin (G3-CA4) in an orthotopic glioma model. Water insoluble combretastatin (CA4) was conjugated to a small-sized water soluble G3-succinamic acid PAMAM dendrimer. Nanoconstruct sizes were determined by TEM to be 3 to 5 nm. Intravenous (i.v.) delivery of G3-CA4 in an orthotopic glioma model produced a long-lived ischemia accompanied by necrosis at the core of the tumor but leaving a rim of viable tissue. In contrast, delivery of CA4 alone has no therapeutic effect in an experimental rat model of glioma.
RESUMEN
Transition metals are essential, but deregulation of their metabolism causes toxicity. Here, we report that the compound NSC319726 binds copper to induce oxidative stress and arrest glioblastoma-patient-derived cells at picomolar concentrations. Pharmacogenomic analysis suggested that NSC319726 and 65 other structural analogs exhibit lethality through metal binding. Although NSC319726 has been reported to function as a zinc ionophore, we report here that this compound binds to copper to arrest cell growth. We generated and validated pharmacogenomic predictions: copper toxicity was substantially inhibited by hypoxia, through an hypoxia-inducible-factor-1α-dependent pathway; copper-bound NSC319726 induced the generation of reactive oxygen species and depletion of deoxyribosyl purines, resulting in cell-cycle arrest. These results suggest that metal-induced DNA damage may be a consequence of exposure to some xenobiotics, therapeutic agents, as well as other causes of copper dysregulation, and reveal a potent mechanism for targeting glioblastomas.
Asunto(s)
Antineoplásicos/química , Antineoplásicos/farmacología , Puntos de Control del Ciclo Celular/efectos de los fármacos , Cobre/metabolismo , Glioblastoma/tratamiento farmacológico , Tiosemicarbazonas/química , Tiosemicarbazonas/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Femenino , Glioblastoma/metabolismo , Humanos , Masculino , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Células Tumorales CultivadasRESUMEN
To understand how genomic heterogeneity of glioblastoma (GBM) contributes to poor therapy response, we performed DNA and RNA sequencing on GBM samples and the neurospheres and orthotopic xenograft models derived from them. We used the resulting dataset to show that somatic driver alterations including single-nucleotide variants, focal DNA alterations and oncogene amplification on extrachromosomal DNA (ecDNA) elements were in majority propagated from tumor to model systems. In several instances, ecDNAs and chromosomal alterations demonstrated divergent inheritance patterns and clonal selection dynamics during cell culture and xenografting. We infer that ecDNA was unevenly inherited by offspring cells, a characteristic that affects the oncogenic potential of cells with more or fewer ecDNAs. Longitudinal patient tumor profiling found that oncogenic ecDNAs are frequently retained throughout the course of disease. Our analysis shows that extrachromosomal elements allow rapid increase of genomic heterogeneity during GBM evolution, independently of chromosomal DNA alterations.
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Neoplasias Encefálicas/genética , ADN de Neoplasias/genética , Glioblastoma/genética , Animales , Línea Celular Tumoral , Cromosomas , Femenino , Genómica/métodos , Herencia , Humanos , Ratones , Ratones Desnudos , Oncogenes , Polimorfismo de Nucleótido SimpleRESUMEN
Glioblastoma is an aggressive primary brain tumor predominantly localized to the cerebral cortex. We developed a panel of patient-derived mouse orthotopic xenografts (PDOX) for preclinical drug studies by implanting cancer stem cells (CSC) cultured from fresh surgical specimens intracranially into 8-wk-old female athymic nude mice. Here we optimize the glioblastoma PDOX model by assessing the effect of implantation location on tumor growth, survival, and histologic characteristics. To trace the distribution of intracranial injections, toluidine blue dye was injected at 4 locations with defined mediolateral, anterioposterior, and dorsoventral coordinates within the cerebral cortex. Glioblastoma CSC from 4 patients and a glioblastoma nonstem-cell line were then implanted by using the same coordinates for evaluation of tumor location, growth rate, and morphologic and histologic features. Dye injections into one of the defined locations resulted in dye dissemination throughout the ventricles, whereas tumor cell implantation at the same location resulted in a much higher percentage of small multifocal ventricular tumors than did the other 3 locations tested. Ventricular tumors were associated with a lower tumor growth rate, as measured by in vivo bioluminescence imaging, and decreased survival in 4 of 5 cell lines. In addition, tissue oxygenation, vasculature, and the expression of astrocytic markers were altered in ventricular tumors compared with nonventricular tumors. Based on this information, we identified an optimal implantation location that avoided the ventricles and favored cortical tumor growth. To assess the effects of stress from oral drug administration, mice that underwent daily gavage were compared with stress-positive and -negative control groups. Oral gavage procedures did not significantly affect the survival of the implanted mice or physiologic measurements of stress. Our findings document the importance of optimization of the implantation site for preclinical mouse models of glioblastoma.
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Neoplasias Encefálicas/patología , Glioblastoma/patología , Células Madre Neoplásicas/patología , Investigación Biomédica Traslacional/métodos , Animales , Línea Celular Tumoral , Proliferación Celular , Supervivencia Celular , Femenino , Manejo Psicológico , Xenoinjertos , Humanos , Ratones Desnudos , Trasplante de Neoplasias , Células Madre Neoplásicas/trasplante , Estrés Psicológico/complicaciones , Estrés Psicológico/patología , Factores de Tiempo , Carga TumoralRESUMEN
We leveraged IDH wild-type glioblastomas, derivative neurospheres, and single-cell gene expression profiles to define three tumor-intrinsic transcriptional subtypes designated as proneural, mesenchymal, and classical. Transcriptomic subtype multiplicity correlated with increased intratumoral heterogeneity and presence of tumor microenvironment. In silico cell sorting identified macrophages/microglia, CD4+ T lymphocytes, and neutrophils in the glioma microenvironment. NF1 deficiency resulted in increased tumor-associated macrophages/microglia infiltration. Longitudinal transcriptome analysis showed that expression subtype is retained in 55% of cases. Gene signature-based tumor microenvironment inference revealed a decrease in invading monocytes and a subtype-dependent increase in macrophages/microglia cells upon disease recurrence. Hypermutation at diagnosis or at recurrence associated with CD8+ T cell enrichment. Frequency of M2 macrophages detection associated with short-term relapse after radiation therapy.
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Regulación Neoplásica de la Expresión Génica , Glioblastoma/genética , Microambiente Tumoral/inmunología , Perfilación de la Expresión Génica , Glioblastoma/inmunología , Glioblastoma/patología , Humanos , Fenotipo , Recurrencia , Análisis de Supervivencia , Linfocitos T/inmunologíaRESUMEN
Glioma cells produce vascular endothelial growth factor (VEGF) to induce vascularization and thereby supply the malignant tissue with oxygen and nutrients. However, little is known about the direct effects of VEGF on tumor cells. In this study, we investigate the ability of VEGF to promote proliferation and invasion of human glioma cells (U251n). Since the chemokine and its receptor, SDF-1/CXCR4, promote glioma cell proliferation and are up-regulated in human glioblastomas, we also tested the effects of VEGF on SDF-1 and CXCR4 mRNA expression. Using cell culture, the effect of VEGF on proliferation of U251n cells was measured using ELISA to detect incorporated BrdU as a marker of DNA syntheses. The effects of VEGF and SDF-1 on U251n cell invasion and proliferation were measured using inhibitors to VEGF receptor1 and receptor2, DC101 and MF1, respectively, and a CXCR4 antagonist (AMD3100). SDF-1 and CXCR4 mRNA expression in U251n and U87MG cells were measured using quantitative PCR. VEGF antisense phosphorothioate oligodeoxynucleotide (AS-VEGF) was also used to down-regulate VEGF expression in U251n cells. VEGF significantly increased U251n cell proliferation and invasion in a dose-dependent manner. These effects were blocked by the VEGF receptor inhibitors, DC101/MF1. The CXCR4 antagonist AMD3100 blocked U251n increased invasion, but not proliferation. CXCR4 and SDF-1 mRNA were up-regulated when U251n and U87MG cells were treated with VEGF. Eight micrometer VEGF antisense phosphorothioate oligodeoxynucleotide (AS-VEGF) down-regulated CXCR4 and SDF-1 mRNA levels in U251n cells. VEGF has a direct effect on U251n glioma cell proliferation and invasion. VEGF up-regulates SDF-1 and CXCR4 mRNA expression, and contributes to U251n cell invasion.
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Línea Celular Tumoral/patología , Quimiocinas CXC/metabolismo , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Receptores CXCR4/metabolismo , Factor A de Crecimiento Endotelial Vascular/farmacología , Línea Celular Tumoral/efectos de los fármacos , Línea Celular Tumoral/metabolismo , Proliferación Celular/efectos de los fármacos , Quimiocina CXCL12 , Quimiocinas CXC/genética , Quimiocinas CXC/farmacología , Quimiotaxis/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Glioma , Humanos , Invasividad Neoplásica , ARN Mensajero/metabolismo , Receptores CXCR4/antagonistas & inhibidores , Receptores CXCR4/genética , Proteínas Recombinantes/farmacología , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Factor A de Crecimiento Endotelial Vascular/genéticaRESUMEN
Glioblastoma (GBM) is a highly invasive brain tumor. Perivascular invasion, autovascularization and vascular co-option occur throughout the disease and lead to tumor invasion and progression. The molecular basis for perivascular invasion, i.e., the interaction of glioma tumor cells with endothelial cells is not well characterized. Recent studies indicate that glioma cells have increased expression of CXCR4. We investigated the in-vivo role of CXCR4 in perivascular invasion of glioma cells using shRNA-mediated knock down of CXCR4. We show that primary cultures of human glioma stem cells HF2303 and mouse glioma GL26-Cit cells exhibit significant migration towards human (HBMVE) and mouse (MBVE) brain microvascular endothelial cells. Blocking CXCR4 on tumor cells with AMD3100 in-vitro, inhibits migration of GL26-Cit and HF2303 toward MBVE and HBMVE cells. Additionally, genetic down regulation of CXCR4 in mouse glioma GL26-Cit cells inhibits their in-vitro migration towards MBVE cells; in an in-vivo intracranial mouse model, these cells display reduced tumor growth and perivascular invasion, leading to increased survival. Quantitative analysis of brain sections showed that CXCR4 knockdown tumors are less invasive. Lastly, we tested the effects of radiation on CXCR4 knock down GL26-Cit cells in an orthotopic brain tumor model. Radiation treatment increased apoptosis of CXCR4 downregulated tumor cells and prolonged median survival. In summary, our data suggest that CXCR4 signaling is critical for perivascular invasion of GBM cells and targeting this receptor makes tumors less invasive and more sensitive to radiation therapy. Combination of CXCR4 knock down and radiation treatment might improve the efficacy of GBM therapy.