RESUMEN
Capicua (CIC) is a transcriptional repressor that counteracts activation of genes downstream of receptor tyrosine kinase (RTK)/Ras/ERK signaling. It is well-established that tumorigenesis, especially in glioblastoma (GBM), is attributed to hyperactive RTK/Ras/ERK signaling. While CIC is mutated in other tumors, here we show that CIC has a tumor suppressive function in GBM through an alternative mechanism. We find that CIC protein levels are negligible in GBM due to continuous proteasome-mediated degradation, which is mediated by the E3 ligase PJA1 and show that this occurs through binding of CIC to its DNA target and phosphorylation on residue S173. PJA1 knockdown increased CIC stability and extended survival using in-vivo models of GBM. Deletion of the ERK binding site resulted in stabilization of CIC and increased therapeutic efficacy of ERK inhibition in GBM models. Our results provide a rationale to target CIC degradation in Ras/ERK-driven tumors, including GBM, to increase efficacy of ERK inhibitors.
Asunto(s)
Glioblastoma/metabolismo , Glioblastoma/patología , Proteínas Represoras/metabolismo , Animales , Carcinogénesis/metabolismo , Carcinogénesis/patología , Línea Celular Tumoral , Proliferación Celular/genética , Proliferación Celular/fisiología , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/patología , Drosophila , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Regulación del Desarrollo de la Expresión Génica/genética , Regulación del Desarrollo de la Expresión Génica/fisiología , Células HEK293 , Humanos , Masculino , Ratones Endogámicos C57BL , Ratones Transgénicos , Mutación , Proteínas Represoras/genética , Transducción de Señal/genética , Transducción de Señal/fisiologíaRESUMEN
PURPOSE: Hexokinase II (HK2) protein expression is elevated in glioblastoma (GBM), and we have shown that HK2 could serve as an effective therapeutic target for GBM. Here, we interrogated compounds that target HK2 effectively and restrict tumor growth in cell lines, patient-derived glioma stem cells (GSCs), and mouse models of GBM.Experimental Design: We performed a screen using a set of 15 drugs that were predicted to inhibit the HK2-associated gene signature. We next determined the EC50 of the compounds by treating glioma cell lines and GSCs. Selected compounds showing significant impact in vitro were used to treat mice and examine their effect on survival and tumor characteristics. The effect of compounds on the metabolic activity in glioma cells was also assessed in vitro. RESULTS: This screen identified the azole class of antifungals as inhibitors of tumor metabolism. Among the compounds tested, ketoconazole and posaconazole displayed the greatest inhibitory effect on GBM both in vitro and in vivo. Treatment of mice bearing GBM with ketoconazole and posaconazole increased their survival, reduced tumor cell proliferation, and decreased tumor metabolism. In addition, treatment with azoles resulted in increased proportion of apoptotic cells. CONCLUSIONS: Overall, we provide evidence that azoles exert their effect by targeting genes and pathways regulated by HK2. These findings shed light on the action of azoles in GBM. Combined with existing literature and preclinical results, these data support the value of repurposing azoles in GBM clinical trials.
Asunto(s)
Antineoplásicos/farmacología , Hexoquinasa/antagonistas & inhibidores , Cetoconazol/farmacología , Triazoles/farmacología , Animales , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Metabolismo Energético/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Glioblastoma/genética , Glioblastoma/metabolismo , Hexoquinasa/genética , Hexoquinasa/metabolismo , Humanos , Masculino , Ratones , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Schwannomas are common peripheral nerve sheath tumors that can cause debilitating morbidities. We performed an integrative analysis to determine genomic aberrations common to sporadic schwannomas. Exome sequence analysis with validation by targeted DNA sequencing of 125 samples uncovered, in addition to expected NF2 disruption, recurrent mutations in ARID1A, ARID1B and DDR1. RNA sequencing identified a recurrent in-frame SH3PXD2A-HTRA1 fusion in 12/125 (10%) cases, and genomic analysis demonstrated the mechanism as resulting from a balanced 19-Mb chromosomal inversion on chromosome 10q. The fusion was associated with male gender predominance, occurring in one out of every six men with schwannoma. Methylation profiling identified distinct molecular subgroups of schwannomas that were associated with anatomical location. Expression of the SH3PXD2A-HTRA1 fusion resulted in elevated phosphorylated ERK, increased proliferation, increased invasion and in vivo tumorigenesis. Targeting of the MEK-ERK pathway was effective in fusion-positive Schwann cells, suggesting a possible therapeutic approach for this subset of tumors.
Asunto(s)
Metilación de ADN , Neoplasias del Oído/genética , Mutación , Neurilemoma/genética , Neoplasias de la Columna Vertebral/genética , Vestíbulo del Laberinto , Proteínas Adaptadoras del Transporte Vesicular/genética , Animales , Línea Celular Tumoral , Análisis Mutacional de ADN , ADN de Neoplasias , Exoma , Femenino , Fusión Génica , Genoma Humano , Serina Peptidasa A1 que Requiere Temperaturas Altas , Humanos , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , ARN Neoplásico , Análisis de Secuencia de ADN , Análisis de Secuencia de ARN , Serina Endopeptidasas/genéticaRESUMEN
First-line cancer therapies such as alkylating agents and radiation have limited survival benefits for Glioblastoma (GBM) patients. Current research strongly supports the notion that inhibition of aberrant tumor metabolism holds promise as a therapeutic strategy when used in combination with radiation and chemotherapy. Hexokinase 2 (HK2) has been shown to be a key driver of altered metabolism in GBM, and presents an attractive therapeutic target. To date, no study has fully assessed the therapeutic value of targeting HK2 as a mechanism to sensitize cells to standard therapy, namely in the form of radiation and temozolomide (TMZ). Using cell lines and primary cultures of GBM, we showed that inducible knockdown of HK2 altered tumor metabolism, which could not be recapitulated by HK1 or HK3 loss. HK2 loss diminished both in vivo tumor vasculature as well as growth within orthotopic intracranial xenograft models of GBMs, and the survival benefit was additive with radiation and TMZ. Radio-sensitization following inhibition of HK2 was mediated by increased DNA damage, and could be rescued through constitutive activation of ERK signaling. This study supports HK2 as a potentially effective therapeutic target in GBM.
Asunto(s)
Neoplasias Encefálicas/terapia , Glioblastoma/terapia , Hexoquinasa/genética , Interferencia de ARN , Ensayos Antitumor por Modelo de Xenoinjerto , Animales , Antineoplásicos Alquilantes/farmacología , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Proliferación Celular/efectos de la radiación , Quimioradioterapia , Daño del ADN , Dacarbazina/análogos & derivados , Dacarbazina/farmacología , Glioblastoma/metabolismo , Glioblastoma/patología , Células HEK293 , Hexoquinasa/metabolismo , Humanos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/efectos de la radiación , Masculino , Ratones Endogámicos NOD , Ratones SCID , TemozolomidaRESUMEN
The RNAse III endonuclease DICER is a key regulator of microRNA (miRNA) biogenesis and is frequently decreased in a variety of malignancies. We characterized the role of DICER in glioblastoma (GB), specifically demonstrating its effects on the ability of glioma stem-like cells (GSCs) to form tumors in a mouse model of GB. DICER silencing in GSCs reduced their stem cell characteristics, while tumors arising from these cells were more aggressive, larger in volume, and displayed a higher proliferation index and lineage differentiation. The resulting tumors, however, were more sensitive to radiation treatment. Our results demonstrate that DICER silencing enhances the tumorigenic potential of GSCs, providing a platform for analysis of specific relevant miRNAs and development of potentially novel therapies against GB.
Asunto(s)
Neoplasias Encefálicas/genética , ARN Helicasas DEAD-box/metabolismo , Regulación Neoplásica de la Expresión Génica , Glioblastoma/genética , MicroARNs/genética , Células Madre Neoplásicas/metabolismo , Ribonucleasa III/metabolismo , Animales , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/radioterapia , Carcinogénesis/genética , Diferenciación Celular/genética , Línea Celular Tumoral , Proliferación Celular/genética , ARN Helicasas DEAD-box/genética , Técnicas de Silenciamiento del Gen , Glioblastoma/diagnóstico por imagen , Glioblastoma/patología , Glioblastoma/radioterapia , Humanos , Imagen por Resonancia Magnética , Ratones , Ratones Endogámicos NOD , Ratones SCID , Interferencia de ARN , ARN Interferente Pequeño , Ribonucleasa III/genética , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Ras is phosphorylated on a conserved tyrosine at position 32 within the switch I region via Src kinase. This phosphorylation inhibits the binding of effector Raf while promoting the engagement of GTPase-activating protein (GAP) and GTP hydrolysis. Here we identify SHP2 as the ubiquitously expressed tyrosine phosphatase that preferentially binds to and dephosphorylates Ras to increase its association with Raf and activate downstream proliferative Ras/ERK/MAPK signalling. In comparison to normal astrocytes, SHP2 activity is elevated in astrocytes isolated from glioblastoma multiforme (GBM)-prone H-Ras(12V) knock-in mice as well as in glioma cell lines and patient-derived GBM specimens exhibiting hyperactive Ras. Pharmacologic inhibition of SHP2 activity attenuates cell proliferation, soft-agar colony formation and orthotopic GBM growth in NOD/SCID mice and decelerates the progression of low-grade astrocytoma to GBM in a spontaneous transgenic glioma mouse model. These results identify SHP2 as a direct activator of Ras and a potential therapeutic target for cancers driven by a previously 'undruggable' oncogenic or hyperactive Ras.
Asunto(s)
Glioblastoma/enzimología , Proteína Oncogénica p21(ras)/metabolismo , Proteína Tirosina Fosfatasa no Receptora Tipo 11/metabolismo , Animales , Carcinogénesis , Línea Celular , Femenino , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/patología , Humanos , Masculino , Ratones , Ratones Endogámicos ICR , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Proteína Oncogénica p21(ras)/genética , Fosforilación , Proteína Tirosina Fosfatasa no Receptora Tipo 11/genéticaRESUMEN
OBJECT: Intravenous fluorescein sodium has been used during resection of high-grade gliomas to help the surgeon visualize tumor margins. Several studies have reported improved rates of gross-total resection (GTR) using high doses of fluorescein sodium under white light. The recent introduction of a fluorescein-specific camera that allows for high-quality intraoperative imaging and use of very low dose fluorescein has drawn new attention to this fluorophore. However, the ability of fluorescein to specifically stain glioma cells is not yet well understood. METHODS: The authors designed an in vitro model to assess fluorescein uptake in normal human astrocytes and U251 malignant glioma cells. An in vivo experiment was also subsequently designed to study fluorescein uptake by intracranial U87 malignant glioma xenografts in male nonobese diabetic/severe combined immunodeficient mice. A genetically induced mouse glioma model was used to adjust for the possible confounding effect of an inflammatory response in the xenograft model. To assess the intraoperative application of this technology, the authors prospectively enrolled 12 patients who underwent fluorescein-guided resection of their high-grade gliomas using low-dose intravenous fluorescein and a microscope-integrated fluorescence module. Intraoperative fluorescent and nonfluorescent specimens at the tumor margins were randomly analyzed for histopathological correlation. RESULTS: The in vitro and in vivo models suggest that fluorescein demarcation of glioma-invaded brain is the result of distribution of fluorescein into the extracellular space, most likely as a result of an abnormal blood-brain barrier. Glioblastoma tumor cell-specific uptake of fluorescein was not observed, and tumor cells appeared to mostly exclude fluorescein. For the 12 patients who underwent resection of their high-grade gliomas, the histopathological analysis of the resected specimens at the tumor margin confirmed the intraoperative fluorescent findings. Fluorescein fluorescence was highly specific (up to 90.9%) while its sensitivity was 82.2%. False negatives occurred due to lack of fluorescence in areas of diffuse, low-density cellular infiltration. Margins of contrast enhancement based on intraoperative MRI-guided StealthStation neuronavigation correlated well with fluorescent tumor margins. GTR of the contrast-enhancing area as guided by the fluorescent signal was achieved in 100% of cases based on postoperative MRI. CONCLUSIONS: Fluorescein sodium does not appear to selectively accumulate in astrocytoma cells but in extracellular tumor cell-rich locations, suggesting that fluorescein is a marker for areas of compromised blood-brain barrier within high-grade astrocytoma. Fluorescein fluorescence appears to correlate intraoperatively with the areas of MR enhancement, thus representing a practical tool to help the surgeon achieve GTR of the enhancing tumor regions.
Asunto(s)
Astrocitos/metabolismo , Neoplasias Encefálicas/metabolismo , Encéfalo/metabolismo , Fluoresceína/farmacocinética , Glioma/metabolismo , Animales , Astrocitos/efectos de los fármacos , Astrocitos/patología , Encéfalo/efectos de los fármacos , Encéfalo/patología , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Glioma/patología , Humanos , Masculino , Ratones , Microscopía Fluorescente , Distribución TisularRESUMEN
Solid tumors arising from malignant transformation of glial cells are one of the leading causes of central nervous system tumor-related death in children. Recurrence in spite of rigorous surgical and chemoradiation therapies remains a major hurdle in management of these tumors. Here, we investigate the efficacy of the second-generation receptor tyrosine kinase inhibitor nilotinib as a therapeutic option for the management of pediatric gliomas. We have utilized two independent pediatric high-grade glioma cell lines with either high platelet-derived growth factor receptor alpha (PDGFRα) or high PDGFRß expression in in vitro assays to investigate the specific downstream effects of nilotinib treatment. Using in vitro cell-based assays we show that nilotinib inhibits PDGF-BB-dependent activation of PDGFRα. We further show that nilotinib is able to decrease cell proliferation and anchorage-independent growth via suppression of AKT and ERK1/2 signaling pathways. Our results suggest that nilotinib may be effective for management of a PDGFRα-dependent group of pediatric gliomas.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Glioma/patología , Pirimidinas/farmacología , Animales , Becaplermina , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Ensayo de Unidades Formadoras de Colonias , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/uso terapéutico , Glioma/tratamiento farmacológico , Humanos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Ratones , Ratones SCID , Proteína Oncogénica v-akt/metabolismo , Proteínas Proto-Oncogénicas c-sis/metabolismo , Pirimidinas/uso terapéutico , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas/metabolismo , Factores de Tiempo , Vinculina/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
AIMS: Meningiomas are one of the most common brain tumours in adults. Invasive and malignant meningiomas present a significant therapeutic challenge due to high recurrence rates and invasion into surrounding bone, brain, neural and soft tissues. Understanding the molecular mechanism of invasion could help in designing novel therapeutic approaches in order to prevent the need for repeat surgery, decrease morbidity and improve patient survival. The aim of this study was to identify the key factors and underlying mechanisms which govern invasive properties of meningiomas. METHODS: Formalin-fixed paraffin-embedded (FFPE) as well as frozen tumour tissues from bone-invasive, non-invasive and malignant meningiomas were used for RNA microarray, quantitative real-time PCR or Western blot analyses. Malignant meningioma cell lines (F5) were subject to MMP16 downregulation or overexpression and used for in vitro and in vivo functional assays. Subdural xenograft meningioma tumours were generated to study the invasion of tumour cells into brain parenchyma using cell lines with altered MMP16 expression. RESULTS: We establish that the expression level of MMP16 was significantly elevated in both bone-invasive and brain invasive meningiomas. Gain- and loss-of-function experiments indicated a role for MMP16 in meningioma cell movement, invasion and tumour cell growth. Furthermore, MMP16 was shown to positively regulate MMP2, suggesting this mechanism may modulate meningioma invasion in invasive meningiomas. CONCLUSIONS: Overall, the results support a role for MMP16 in promoting invasive properties of the meningioma tumours. Further studies to explore the potential value for clinical use of matrix metalloproteinases inhibitors are warranted.
Asunto(s)
Metaloproteinasa 16 de la Matriz/metabolismo , Neoplasias Meníngeas/patología , Meningioma/patología , Adulto , Animales , Western Blotting , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica/fisiología , Xenoinjertos , Humanos , Metaloproteinasa 2 de la Matriz/biosíntesis , Neoplasias Meníngeas/metabolismo , Meningioma/metabolismo , Ratones , Ratones Endogámicos NOD , Ratones SCID , Invasividad Neoplásica , Análisis de Secuencia por Matrices de Oligonucleótidos , Reacción en Cadena en Tiempo Real de la Polimerasa , TransfecciónRESUMEN
UNLABELLED: Alkylating agents are a first-line therapy for the treatment of several aggressive cancers, including pediatric glioblastoma, a lethal tumor in children. Unfortunately, many tumors are resistant to this therapy. We sought to identify ways of sensitizing tumor cells to alkylating agents while leaving normal cells unharmed, increasing therapeutic response while minimizing toxicity. Using an siRNA screen targeting over 240 DNA damage response genes, we identified novel sensitizers to alkylating agents. In particular, the base excision repair (BER) pathway, including 3-methylpurine-DNA glycosylase (MPG), as well as ataxia telangiectasia mutated (ATM), were identified in our screen. Interestingly, we identified MPG as a direct novel substrate of ATM. ATM-mediated phosphorylation of MPG was required for enhanced MPG function. Importantly, combined inhibition or loss of MPG and ATM resulted in increased alkylating agent-induced cytotoxicity in vitro and prolonged survival in vivo. The discovery of the ATM-MPG axis will lead to improved treatment of alkylating agent-resistant tumors. SIGNIFICANCE: Inhibition of ATM and MPG-mediated BER cooperate to sensitize tumor cells to alkylating agents, impairing tumor growth in vitro and in vivo with no toxicity to normal cells, providing an ideal therapeutic window.
Asunto(s)
Antineoplásicos Alquilantes/farmacología , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , ADN Glicosilasas/metabolismo , Resistencia a Antineoplásicos , Factores de Edad , Animales , Línea Celular Tumoral , Análisis por Conglomerados , Variaciones en el Número de Copia de ADN , Reparación del ADN , Dacarbazina/análogos & derivados , Dacarbazina/farmacología , Modelos Animales de Enfermedad , Resistencia a Antineoplásicos/genética , Activación Enzimática , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Glioblastoma/tratamiento farmacológico , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/mortalidad , Glioblastoma/patología , Humanos , Modelos Biológicos , Fosforilación , Interferencia de ARN , ARN Interferente Pequeño/genética , Temozolomida , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Mutations in Ras GTPase and various other components of the Ras signaling pathways are among the most common genetic alterations in human cancers and also have been identified in several familial developmental syndromes. Over the past few decades it has become clear that the activity or the oncogenic potential of Ras is dependent on the nonreceptor tyrosine kinase Src to promote the Ras/Raf/MAPK pathway essential for proliferation, differentiation, and survival of eukaryotic cells. However, no direct relationship between Ras and Src has been established. We show here that Src binds to and phosphorylates GTP-, but not GDP-, loaded Ras on a conserved Y32 residue within the switch I region in vitro and that in vivo, Ras-Y32 phosphorylation markedly reduces the binding to effector Raf and concomitantly increases binding to GTPase-activating proteins and the rate of GTP hydrolysis. These results suggest that, in the context of predetermined crystallographic structures, Ras-Y32 serves as an Src-dependent keystone regulatory residue that modulates Ras GTPase activity and ensures unidirectionality to the Ras GTPase cycle.
Asunto(s)
GTP Fosfohidrolasas/metabolismo , Proteínas de la Membrana/metabolismo , Fosfotirosina/metabolismo , Familia-src Quinasas/metabolismo , Secuencia de Aminoácidos , Animales , Línea Celular , GTP Fosfohidrolasas/química , Proteínas Activadoras de GTPasa/metabolismo , Guanosina Trifosfato/metabolismo , Humanos , Hidrólisis , Proteínas de la Membrana/química , Ratones , Modelos Moleculares , Datos de Secuencia Molecular , Proteínas Mutantes/metabolismo , Fosforilación , Unión Proteica , Quinasas raf/metabolismoRESUMEN
Glioblastoma multiforme (GBM) is characterized by a pathogenic vasculature that drives aggressive local invasion. Recent work suggests that GBM cells recruit bone marrow-derived progenitor cells (BMDC) to facilitate recurrence after radiotherapy, but how this may be achieved is unclear. In this study, we established the spatiotemporal and regional contributions of perivascular BMDCs (pBMDC) to GBM development. We found an increased recruitment of BMDCs to GBM in response to tumor growth and following radiotherapy. However, in this study, BMDCs did not differentiate into endothelial cells directly but rather provided a perivascular support role. The pBMDCs were shown to associate with tumor vasculature in a highly region-dependent manner, with central vasculature requiring minimal pBMDC support. Region-dependent association of pBMDC was regulated by VEGF. In the absence of VEGF, following radiotherapy or antiangiogenic therapy, we documented an increase in Ang2 that regulated recruitment of pBMDCs to maintain the vulnerable central vasculature. Together, our results strongly suggested that targeting pBMDC influx along with radiation or antiangiogenic therapy would be critical to prevent vascular recurrence of GBM.
Asunto(s)
Células de la Médula Ósea/metabolismo , Células de la Médula Ósea/patología , Glioblastoma/metabolismo , Glioblastoma/patología , Factor A de Crecimiento Endotelial Vascular/metabolismo , Animales , Diferenciación Celular , Línea Celular Tumoral , Modelos Animales de Enfermedad , Glioblastoma/tratamiento farmacológico , Glioblastoma/radioterapia , Humanos , Ratones Transgénicos , Estadificación de Neoplasias , Neovascularización Patológica , Proteínas de Transporte Vesicular/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
BACKGROUND: Although anti-angiogenic therapy (AATx) holds great promise for treatment of malignant gliomas, its therapeutic efficacy is not well understood and can potentially increase the aggressive recurrence of gliomas. It is essential to establish sensitive, noninvasive biomarkers that can detect failure of AATx and tumor recurrence early so that timely adaptive therapy can be instituted. We investigated the efficacy of MRI biomarkers that can detect response to different classes of AATxs used alone or in combination with radiation. METHODS: Murine intracranial glioma xenografts (NOD/SCID) were treated with sunitinib, VEGF-trap or B20 (a bevacizumab equivalent) alone or in combination with radiation. MRI images were acquired longitudinally before and after treatment, and various MRI parameters (apparent diffusion coefficient, T1w + contrast, dynamic contrast-enhanced [DCE], initial area under the contrast enhancement curve, and cerebral blood flow) were correlated to tumor cell proliferation, overall tumor growth, and tumor vascularity. RESULTS: Combinatorial therapies reduced tumor growth rate more efficiently than monotherapies. Apparent diffusion coefficient was an accurate measure of tumor cell density. Vascular endothelial growth factor (VEGF)-trap or B20, but not sunitinib, resulted in significant reduction or complete loss of contrast enhancement. This reduction was not due to a reduction in tumor growth or microvascular density, but rather was explained by a reduction in vessel permeability and perfusion. We established that contrast enhancement does not accurately reflect tumor volume or vascular density; however, DCE-derived parameters can be used as efficient noninvasive biomarkers of response to AATx. CONCLUSIONS: MRI parameters following therapy vary based on class of AATx. Validation of clinically relevant MRI parameters for individual AATx agents is necessary before incorporation into routine practice.
Asunto(s)
Inhibidores de la Angiogénesis/uso terapéutico , Neoplasias Encefálicas/terapia , Glioblastoma/terapia , Imagen por Resonancia Magnética , Animales , Anticuerpos Monoclonales Humanizados/uso terapéutico , Bevacizumab , Biomarcadores , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/radioterapia , Línea Celular Tumoral , Terapia Combinada , Glioblastoma/tratamiento farmacológico , Glioblastoma/patología , Glioblastoma/radioterapia , Humanos , Procesamiento de Imagen Asistido por Computador , Indoles/uso terapéutico , Ratones , Pirroles/uso terapéutico , Receptores de Factores de Crecimiento Endotelial Vascular/uso terapéutico , Proteínas Recombinantes de Fusión/uso terapéutico , SunitinibRESUMEN
Gliomas are a heterogeneous group of tumors that show variable proliferative potential, invasiveness, aggressiveness, histological grading, and clinical behavior. In this review, we focus on glioblastoma multiforme (GBM), a grade IV glioma, which is the most common and malignant of primary adult brain tumors. Research over the past several decades has revealed the existence of extensive cellular, molecular, genetic, epigenetic, and metabolic heterogeneity among tumors of the same grade and even within individual tumors. Evaluation of different tumor types has shown that tumors with advanced grade and clinical aggressiveness also display enhanced molecular, cellular, and microenvironmental heterogeneity. From a therapeutic standpoint, this heterogeneity is a major clinical hurdle for devising effective therapeutic strategies for patients and challenges personalized medicine. In this review, we will highlight key aspects of GBM heterogeneity, directing special attention to regional heterogeneity, hypoxia, genomic heterogeneity, tumor-specific metabolic reprogramming, neovascularization or angiogenesis, and stromal immune cells. We will further discuss the clinical implications of GBM heterogeneity in the context of therapy.
Asunto(s)
Neoplasias Encefálicas/fisiopatología , Glioblastoma/fisiopatología , Microambiente Tumoral , Adulto , Encéfalo/irrigación sanguínea , Encéfalo/fisiopatología , Neoplasias Encefálicas/complicaciones , Neoplasias Encefálicas/metabolismo , Proliferación Celular , Glioblastoma/complicaciones , Glioblastoma/metabolismo , Humanos , Hipoxia Encefálica/complicaciones , Neovascularización PatológicaRESUMEN
Spectral mapping of nanoparticles with surface enhanced Raman scattering (SERS) capability in the near-infrared range is an emerging molecular imaging technique. We used magnetic resonance image-guided transcranial focused ultrasound (TcMRgFUS) to reversibly disrupt the blood-brain barrier (BBB) adjacent to brain tumor margins in rats. Glioma cells were found to internalize SERS capable nanoparticles of 50nm or 120nm physical diameter. Surface coating with anti-epidermal growth factor receptor antibody or non-specific human immunoglobulin G, resulted in enhanced cell uptake of nanoparticles in-vitro compared to nanoparticles with methyl terminated 12-unit polyethylene glycol surface. BBB disruption permitted the delivery of SERS capable spherical 50 or 120nm gold nanoparticles to the tumor margins. Thus, nanoparticles with SERS imaging capability can be delivered across the BBB non-invasively using TcMRgFUS and have the potential to be used as optical tracking agents at the invasive front of malignant brain tumors. FROM THE CLINICAL EDITOR: This study demonstrates the use of magnetic resonance image-guided transcranial focused ultrasound to open the BBB and enable spectral mapping of nanoparticles with surface enhanced Raman scattering (SERS)-based molecular imaging for experimental tumor tracking.
Asunto(s)
Antineoplásicos/uso terapéutico , Barrera Hematoencefálica/metabolismo , Barrera Hematoencefálica/efectos de la radiación , Neoplasias Encefálicas/tratamiento farmacológico , Nanopartículas/administración & dosificación , Nanopartículas/metabolismo , Sonido , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/química , Encéfalo/metabolismo , Línea Celular Tumoral , Sistemas de Liberación de Medicamentos , Receptores ErbB/antagonistas & inhibidores , Humanos , Microscopía Fluorescente , RatasRESUMEN
We have successfully integrated previously established Intracranial window (ICW) technology (1-4) with intravital 2-photon confocal microscopy to develop a novel platform that allows for direct long-term visualization of tissue structure changes intracranially. Imaging at a single cell resolution in a real-time fashion provides supplementary dynamic information beyond that provided by standard end-point histological analysis, which looks solely at 'snap-shot' cross sections of tissue. Establishing this intravital imaging technique in fluorescent chimeric mice, we are able to image four fluorescent channels simultaneously. By incorporating fluorescently labeled cells, such as GFP+ bone marrow, it is possible to track the fate of these cells studying their long-term migration, integration and differentiation within tissue. Further integration of a secondary reporter cell, such as an mCherry glioma tumor line, allows for characterization of cell:cell interactions. Structural changes in the tissue microenvironment can be highlighted through the addition of intra-vital dyes and antibodies, for example CD31 tagged antibodies and Dextran molecules. Moreover, we describe the combination of our ICW imaging model with a small animal micro-irradiator that provides stereotactic irradiation, creating a platform through which the dynamic tissue changes that occur following the administration of ionizing irradiation can be assessed. Current limitations of our model include penetrance of the microscope, which is limited to a depth of up to 900 µm from the sub cortical surface, limiting imaging to the dorsal axis of the brain. The presence of the skull bone makes the ICW a more challenging technical procedure, compared to the more established and utilized chamber models currently used to study mammary tissue and fat pads (5-7). In addition, the ICW provides many challenges when optimizing the imaging.
Asunto(s)
Neoplasias Encefálicas/patología , Encéfalo/patología , Procesamiento de Imagen Asistido por Computador/métodos , Trepanación/métodos , Animales , Encéfalo/irrigación sanguínea , Encéfalo/efectos de la radiación , Neoplasias Encefálicas/radioterapia , Ratones , Ratones Endogámicos NOD , Ratones SCID , Microscopía Confocal/instrumentación , Microscopía Confocal/métodos , Microscopía de Fluorescencia por Excitación Multifotónica/instrumentación , Microscopía de Fluorescencia por Excitación Multifotónica/métodos , Radio (Anatomía)/anomalías , Técnicas Estereotáxicas , Sinostosis , Trepanación/instrumentación , Cúbito/anomalíasRESUMEN
In vivo and direct imaging of the murine spinal cord and its vasculature using multimodal (optical and acoustic) imaging techniques could significantly advance preclinical studies of the spinal cord. Such intrinsically high resolution and complementary imaging technologies could provide a powerful means of quantitatively monitoring changes in anatomy, structure, physiology and function of the living cord over time after traumatic injury, onset of disease, or therapeutic intervention. However, longitudinal in vivo imaging of the intact spinal cord in rodent models has been challenging, requiring repeated surgeries to expose the cord for imaging or sacrifice of animals at various time points for ex vivo tissue analysis. To address these limitations, we have developed an implantable spinal cord window chamber (SCWC) device and procedures in mice for repeated multimodal intravital microscopic imaging of the cord and its vasculature in situ. We present methodology for using our SCWC to achieve spatially co-registered optical-acoustic imaging performed serially for up to four weeks, without damaging the cord or induction of locomotor deficits in implanted animals. To demonstrate the feasibility, we used the SCWC model to study the response of the normal spinal cord vasculature to ionizing radiation over time using white light and fluorescence microscopy combined with optical coherence tomography (OCT) in vivo. In vivo power Doppler ultrasound and photoacoustics were used to directly visualize the cord and vascular structures and to measure hemoglobin oxygen saturation through the complete spinal cord, respectively. The model was also used for intravital imaging of spinal micrometastases resulting from primary brain tumor using fluorescence and bioluminescence imaging. Our SCWC model overcomes previous in vivo imaging challenges, and our data provide evidence of the broader utility of hybridized optical-acoustic imaging methods for obtaining multiparametric and rich imaging data sets, including over extended periods, for preclinical in vivo spinal cord research.
Asunto(s)
Médula Espinal/cirugía , Tomografía de Coherencia Óptica/métodos , Ultrasonografía/métodos , Animales , Modelos Animales de Enfermedad , Femenino , Hemoglobinas/metabolismo , Ratones , Consumo de Oxígeno , Médula Espinal/irrigación sanguínea , Médula Espinal/diagnóstico por imagen , Traumatismos de la Médula Espinal/diagnóstico , Traumatismos de la Médula Espinal/cirugía , Neoplasias de la Médula Espinal/diagnóstico , Neoplasias de la Médula Espinal/secundarioRESUMEN
Glioblastoma (GBM) is the most common and lethal primary brain tumor. Over the past few years tremendous genomic and proteomic characterization along with robust animal models of GBM have provided invaluable data that show that "GBM", although histologically indistinguishable from one another, are comprised of molecularly heterogenous diseases. In addition, robust pre-clinical models and a better understanding of the core pathways disrupted in GBM are providing a renewed optimism for novel strategies targeting these devastating tumors. Here, we summarize a brief history of the disease, our current molecular knowledge, lessons from animal models and emerging concepts of angiogenesis, invasion, and metabolism in GBM that may lend themselves to therapeutic targeting.
Asunto(s)
Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/genética , Glioblastoma/tratamiento farmacológico , Glioblastoma/genética , Animales , Neoplasias Encefálicas/historia , Modelos Animales de Enfermedad , Glioblastoma/historia , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Terapia Molecular Dirigida/tendencias , Invasividad Neoplásica , ProteómicaRESUMEN
PURPOSE: There is a growing need for noninvasive biomarkers to guide individualized spatiotemporal delivery of radiation therapy (RT) and antiangiogenic (AA) therapy for brain tumors. This study explored early biomarkers of response to RT and the AA agent sunitinib (SU), in a murine intracranial glioma model, using serial magnetic resonance imaging (MRI). METHODS AND MATERIALS: Mice with MRI-visible tumors were stratified by tumor size into 4 therapy arms: control, RT, SU, and SU plus RT (SURT). Single-fraction conformal RT was delivered using MRI and on-line cone beam computed tomography (CT) guidance. Serial MR images (T2-weighted, diffusion, dynamic contrast-enhanced and gadolinium-enhanced T1-weighted scans) were acquired biweekly to evaluate tumor volume, apparent diffusion coefficient (ADC), and tumor perfusion and permeability responses (K(trans), K(ep)). RESULTS: Mice in all treatment arms survived longer than those in control, with a median survival of 35 days for SURT (P<.0001) and 30 days for RT (P=.009) and SU (P=.01) mice vs 26 days for control mice. At Day 3, ADC rise was greater with RT than without (P=.002). Sunitinib treatment reduced tumor perfusion/permeability values with mean K(trans) reduction of 27.6% for SU (P=.04) and 26.3% for SURT (P=.04) mice and mean K(ep) reduction of 38.1% for SU (P=.01) and 27.3% for SURT (P=.02) mice. The magnitude of individual mouse ADC responses at Days 3 and 7 correlated with subsequent tumor growth rate R values of -0.878 (P=.002) and -0.80 (P=.01), respectively. CONCLUSIONS: Early quantitative changes in diffusion and perfusion MRI measures reflect treatment responses soon after starting therapy and thereby raise the potential for these imaging biomarkers to guide adaptive and potentially individualized therapy approaches in the future.
Asunto(s)
Inhibidores de la Angiogénesis/uso terapéutico , Biomarcadores de Tumor/metabolismo , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/radioterapia , Glioma/tratamiento farmacológico , Glioma/radioterapia , Indoles/uso terapéutico , Pirroles/uso terapéutico , Radioterapia Conformacional , Animales , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Terapia Combinada/métodos , Imagen de Difusión por Resonancia Magnética/métodos , Glioma/metabolismo , Glioma/mortalidad , Glioma/patología , Ratones , Ratones Endogámicos NOD , Ratones SCID , Sunitinib , Carga TumoralRESUMEN
BACKGROUND: Bone invasive skull base meningiomas are a subset of meningiomas that present a unique clinical challenge due to brain and neural structure involvement and limitations in complete surgical resection, resulting in higher recurrence and need for repeat surgery. To date, the pathogenesis of meningioma bone invasion has not been investigated. We investigated immunoexpression of proteins implicated in bone invasion in other tumor types to establish their involvement in meningioma bone invasion. METHODS: Retrospective review of our database identified bone invasive meningiomas operated on at our institution over the past 20 years. Using high-throughput tissue microarray (TMA), we established the expression profile of osteopontin (OPN), matrix metalloproteinase-2 (MMP2), and integrin beta-1 (ITGB1). Differential expression in tumor cell and vasculature was evaluated and comparisons were made between meningioma anatomical locations. RESULTS: MMP2, OPN, and ITGB1 immunoreactivity was cytoplasmic in tumor and/or endothelial cells. Noninvasive transbasal meningiomas exhibited higher vascular endothelial cell MMP2 immunoexpression compared to invasive meningiomas. We found higher expression levels of OPN and ITGB1 in bone invasive transbasal compared to noninvasive meningiomas. Strong vascular ITGB1 expression extending from the endothelium through the media and into the adventitia was found in a subset of meningiomas. CONCLUSIONS: We have demonstrated that key proteins are differentially expressed in bone invasive meningiomas and that the anatomical location of bone invasion is a key determinant of expression pattern of MMP1, OPN, and ITGB1. This data provides initial insights into the pathophysiology of bone invasion in meningiomas and identifies factors that can be pursued as potential therapeutic targets.