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BACKGROUND: Neurofibromatosis type 1 and neurofibromatosis type 2 are unrelated, distinct genetic disorders characterized by the development of central and peripheral nervous system tumors. SUMMARY: Neurofibromatosis type 1 is the most common inherited tumor predisposition syndrome with a lifelong increased risk of benign and malignant tumor development, such as glioma and nerve sheath tumors. Neurofibromatosis type 2 classically presents with bilateral vestibular schwannoma, yet it is also associated with non-vestibular schwannoma, meningioma, and ependymoma. Historically, the number of effective therapies for neurofibromatosis-related neoplasms has been limited. KEY MESSAGE: In the past decade, there have been significant advances in the development of precision-based therapies for NF-associated tumors with an increased emphasis on functional outcomes in addition to tumor response. Continued scientific discovery and advancement of targeted therapies for NF-associated neoplasms are necessary to continue to improve outcomes for patients with NF.
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Neoplasias Meníngeas , Neurilemoma , Neurofibromatosis 1 , Neurofibromatosis 2 , Neoplasias del Sistema Nervioso Periférico , Humanos , Neurofibromatosis 2/terapia , Neurofibromatosis 2/genética , Neurofibromatosis 2/patología , Neurofibromatosis 1/complicaciones , Neurofibromatosis 1/terapia , Neurofibromatosis 1/genética , Neurilemoma/cirugía , Neoplasias del Sistema Nervioso Periférico/cirugíaRESUMEN
The polycomb repressive complex 2 (PRC2) exerts oncogenic effects in many tumour types. However, loss-of-function mutations in PRC2 components occur in a subset of haematopoietic malignancies, suggesting that this complex plays a dichotomous and poorly understood role in cancer. Here we provide genomic, cellular, and mouse modelling data demonstrating that the polycomb group gene SUZ12 functions as tumour suppressor in PNS tumours, high-grade gliomas and melanomas by cooperating with mutations in NF1. NF1 encodes a Ras GTPase-activating protein (RasGAP) and its loss drives cancer by activating Ras. We show that SUZ12 loss potentiates the effects of NF1 mutations by amplifying Ras-driven transcription through effects on chromatin. Importantly, however, SUZ12 inactivation also triggers an epigenetic switch that sensitizes these cancers to bromodomain inhibitors. Collectively, these studies not only reveal an unexpected connection between the PRC2 complex, NF1 and Ras, but also identify a promising epigenetic-based therapeutic strategy that may be exploited for a variety of cancers.
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Neoplasias/tratamiento farmacológico , Neoplasias/genética , Proteínas Nucleares/antagonistas & inhibidores , Complejo Represivo Polycomb 2/deficiencia , Factores de Transcripción/antagonistas & inhibidores , Transcripción Genética , Proteínas ras/metabolismo , Animales , Azepinas/farmacología , Azepinas/uso terapéutico , Proteínas de Ciclo Celular , Muerte Celular/efectos de los fármacos , Cromatina/efectos de los fármacos , Cromatina/genética , Cromatina/metabolismo , Modelos Animales de Enfermedad , Epigénesis Genética/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Glioma/tratamiento farmacológico , Glioma/genética , Glioma/patología , Humanos , Melanoma/tratamiento farmacológico , Melanoma/genética , Melanoma/patología , Ratones , Quinasas de Proteína Quinasa Activadas por Mitógenos/antagonistas & inhibidores , Proteínas de Neoplasias , Neoplasias/patología , Neoplasias de la Vaina del Nervio/tratamiento farmacológico , Neoplasias de la Vaina del Nervio/genética , Neoplasias de la Vaina del Nervio/patología , Neurofibromina 1/deficiencia , Neurofibromina 1/genética , Proteínas Nucleares/deficiencia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Complejo Represivo Polycomb 2/genética , Complejo Represivo Polycomb 2/metabolismo , Factores de Transcripción/deficiencia , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Transcripción Genética/efectos de los fármacos , Triazoles/farmacología , Triazoles/uso terapéutico , Proteínas Supresoras de Tumor/deficiencia , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Proteínas ras/antagonistas & inhibidoresRESUMEN
Organized and hosted by the Children's Tumor Foundation (CTF), the Neurofibromatosis (NF) conference is the premier annual gathering for clinicians and researchers interested in neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis (SWN). The 2016 edition constituted a blend of clinical and basic aspects of NF research that helped in clarifying different advances in the field. The incorporation of next generation sequencing is changing the way genetic diagnostics is performed for NF and related disorders, providing solutions to problems like genetic heterogeneity, overlapping clinical manifestations, or the presence of mosaicism. The transformation from plexiform neurofibroma (PNF) to malignant peripheral nerve sheath tumor (MPNST) is being clarified, along with new management and treatments for benign and premalignant tumors. Promising new cellular and in vivo models for understanding the musculoskeletal abnormalities in NF1, the development of NF2 or SWN associated schwannomas, and clarifying the cells that give rise to NF1-associated optic pathway glioma were presented. The interaction of neurofibromin and SPRED1 was described comprehensively, providing functional insight that will help in the interpretation of pathogenicity of certain missense variants identified in NF1 and Legius syndrome patients. Novel promising imaging techniques are being developed, as well as new integrative and holistic management models for patients that take into account psychological, social, and biological factors. Importantly, new therapeutic approaches for schwannomas, meningiomas, ependymomas, PNF, and MPNST are being pursued. This report highlights the major advances that were presented at the 2016 CTF NF conference.
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Neurilemoma/diagnóstico , Neurilemoma/etiología , Neurofibromatosis/diagnóstico , Neurofibromatosis/etiología , Neurofibromatosis 1/diagnóstico , Neurofibromatosis 1/etiología , Neurofibromatosis 2/diagnóstico , Neurofibromatosis 2/etiología , Neoplasias Cutáneas/diagnóstico , Neoplasias Cutáneas/etiología , Animales , Manejo de la Enfermedad , Modelos Animales de Enfermedad , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Humanos , Técnicas de Diagnóstico Molecular , Neurilemoma/terapia , Neurofibromatosis/terapia , Neurofibromatosis 1/terapia , Neurofibromatosis 2/terapia , Neoplasias Cutáneas/terapia , Investigación Biomédica TraslacionalRESUMEN
In vitro drug sensitivity screens are important tools in the discovery of anti-cancer drug combination therapies. Typically, these in vitro drug screens are performed on cells grown in a monolayer. However, these two-dimensional (2D) models are considered less accurate compared to three-dimensional (3D) spheroid cell models; this is especially true for glioma stem cell lines. Cells grown in spheres activate different signaling pathways and are considered more representative of in vivo models than monolayer cell lines. This protocol describes a method for in vitro drug screening of spheroid lines; mouse and human glioma stem cell lines are used as an example. This protocol describes a 3D spheroid drug sensitivity and synergy assay that can be used to determine if a drug or drug combination induces cell death and if two drugs synergize. Glioma stem cell lines are modified to express RFP. Cells are plated in low attachment round well bottom 96 plates, and spheres are allowed to form overnight. Drugs are added, and the growth is monitored by measuring the RFP signal over time using the Incucyte live imaging system, a fluorescence microscope embedded in the tissue culture incubator. Half maximal inhibitory concentration (IC50), median lethal dose (LD50), and synergy score are subsequently calculated to evaluate sensitivities to drugs alone or in combination. The three-dimensional nature of this assay provides a more accurate reflection of tumor growth, behavior, and drug sensitivities in vivo, thus forming the basis for further preclinical investigation.
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Glioma , Esferoides Celulares , Humanos , Ratones , Animales , Evaluación Preclínica de Medicamentos/métodos , Línea Celular Tumoral , Esferoides Celulares/patología , Glioma/patología , Células Madre Neoplásicas/patologíaRESUMEN
Neurofibromatosis Type 1 (NF1) patients develop an array of benign and malignant tumors, of which Malignant Peripheral Nerve Sheath Tumors (MPNST) and High Grade Gliomas (HGG) have a dismal prognosis. About 15-20% of individuals with NF1 develop brain tumors and one third of these occur outside of the optic pathway. These non-optic pathway gliomas are more likely to progress to malignancy, especially in adults. Despite their low frequency, high grade gliomas have a disproportional effect on the morbidity of NF1 patients. In vitro drug combination screens have not been performed on NF1-associated HGG, hindering our ability to develop informed clinical trials. Here we present the first in vitro drug combination screen (21 compounds alone or in combination with MEK or PI3K inhibitors) on the only human NF1 patient derived HGG cell line available and on three mouse glioma cell lines derived from the NF1-P53 genetically engineered mouse model, which sporadically develop HGG. These mouse glioma cell lines were never exposed to serum, grow as spheres and express markers that are consistent with an Oligodendrocyte Precursor Cell (OPC) lineage origin. Importantly, even though the true cell of origin for HGG remains elusive, they are thought to arise from the OPC lineage. We evaluated drug sensitivities of the three murine glioma cell lines in a 3D spheroid growth assay, which more accurately reflects drug sensitivities in vivo. Excitingly, we identified six compounds targeting HDACs, BRD4, CHEK1, BMI-1, CDK1/2/5/9, and the proteasome that potently induced cell death in our NF1-associated HGG. Moreover, several of these inhibitors work synergistically with either MEK or PI3K inhibitors. This study forms the basis for further pre-clinical evaluation of promising targets, with an eventual hope to translate these to the clinic.
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Glioma , Neurofibromatosis 1 , Adulto , Humanos , Ratones , Animales , Neurofibromatosis 1/metabolismo , Fosfatidilinositol 3-Quinasas , Proteínas Nucleares , Factores de Transcripción , Glioma/tratamiento farmacológico , Combinación de Medicamentos , Quinasas de Proteína Quinasa Activadas por Mitógenos , Proteínas de Ciclo CelularRESUMEN
Benign peripheral nerve sheath tumors (PNSTs) are a characteristic feature of neurofibromatosis type I (NF1) patients. NF1 individuals have an 8-13% lifetime risk of developing a malignant PNST (MPNST). Atypical neurofibromas are symptomatic, hypercellular PNSTs, composed of cells with hyperchromatic nuclei in the absence of mitoses. Little is known about the origin and nature of atypical neurofibromas in NF1 patients. In this study, we classified the atypical neurofibromas in the spectrum of NF1-associated PNSTs by analyzing 65 tumor samples from 48 NF1 patients. We compared tumor-specific chromosomal copy number alterations between benign neurofibromas, atypical neurofibromas, and MPNSTs (low-, intermediate-, and high-grade) by karyotyping and microarray-based comparative genome hybridization (aCGH). In 15 benign neurofibromas (4 subcutaneous and 11 plexiform), no copy number alterations were found, except a single event in a plexiform neurofibroma. One highly significant recurrent aberration (15/16) was identified in the atypical neurofibromas, namely a deletion with a minimal overlapping region (MOR) in chromosome band 9p21.3, including CDKN2A and CDKN2B. Copy number loss of the CDKN2A/B gene locus was one of the most common events in the group of MPNSTs, with deletions in low-, intermediate-, and high-grade MPNSTs. In one tumor, we observed a clear transition from a benign-atypical neurofibroma toward an intermediate-grade MPNST, confirmed by both histopathology and aCGH analysis. These data support the hypothesis that atypical neurofibromas are premalignant tumors, with the CDKN2A/B deletion as the first step in the progression toward MPNST.
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Neoplasias de la Vaina del Nervio/genética , Neoplasias de la Vaina del Nervio/patología , Neurofibroma/patología , Neurofibromatosis 1/patología , Lesiones Precancerosas/patología , Adolescente , Adulto , Anciano , Niño , Aberraciones Cromosómicas , Hibridación Genómica Comparativa/métodos , Inhibidor p15 de las Quinasas Dependientes de la Ciclina/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Variaciones en el Número de Copia de ADN , Genes de Neurofibromatosis 1 , Humanos , Cariotipificación/métodos , Masculino , Persona de Mediana Edad , Mutación , Neurofibroma/genética , Neurofibromatosis 1/genética , Lesiones Precancerosas/genética , Factores de Riesgo , Células Tumorales Cultivadas , Proteína p53 Supresora de Tumor/genética , Adulto JovenRESUMEN
How the glioma immune microenvironment fosters tumorigenesis remains incompletely defined. Here, we use single-cell RNA-sequencing and multiplexed tissue-imaging to characterize the composition, spatial organization, and clinical significance of extracellular purinergic signaling in glioma. We show that microglia are the predominant source of CD39, while tumor cells principally express CD73. In glioblastoma, CD73 is associated with EGFR amplification, astrocyte-like differentiation, and increased adenosine, and is linked to hypoxia. Glioblastomas enriched for CD73 exhibit inflammatory microenvironments, suggesting that purinergic signaling regulates immune adaptation. Spatially-resolved single-cell analyses demonstrate a strong spatial correlation between tumor-CD73 and microglial-CD39, with proximity associated with poor outcomes. Similar spatial organization is present in pediatric high-grade gliomas including H3K27M-mutant diffuse midline glioma. These data reveal that purinergic signaling in gliomas is shaped by genotype, lineage, and functional state, and that core enzymes expressed by tumor and myeloid cells are organized to promote adenosine-rich microenvironments potentially amenable to therapeutic targeting.
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Glioblastoma , Glioma , 5'-Nucleotidasa/genética , Adenosina , Niño , Glioblastoma/genética , Humanos , Análisis de la Célula Individual , Análisis Espacial , Microambiente TumoralRESUMEN
Malignant tumors exhibit high degrees of genomic heterogeneity at the cellular level, leading to the view that subpopulations of tumor cells drive growth and treatment resistance. To examine the degree to which tumors also exhibit metabolic heterogeneity at the level of individual cells, we employed multi-isotope imaging mass spectrometry (MIMS) to quantify utilization of stable isotopes of glucose and glutamine along with a label for cell division. Mouse models of melanoma and malignant peripheral nerve sheath tumors (MPNSTs) exhibited striking heterogeneity of substrate utilization, evident in both proliferating and non-proliferating cells. We identified a correlation between metabolic heterogeneity, proliferation, and therapeutic resistance. Heterogeneity in metabolic substrate usage as revealed by incorporation of glucose and glutamine tracers is thus a marker for tumor proliferation. Collectively, our data demonstrate that MIMS provides a powerful tool with which to dissect metabolic functions of individual cells within the native tumor environment.
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While KRAS mutations are common in non-small cell lung cancer (NSCLC), effective treatments are lacking. Here, we report that half of KRAS-mutant NSCLCs aberrantly express the homeobox protein HOXC10, largely due to unappreciated defects in PRC2, which confers sensitivity to combined BET/MEK inhibitors in xenograft and PDX models. Efficacy of the combination is dependent on suppression of HOXC10 by BET inhibitors. We further show that HOXC10 regulates the expression of pre-replication complex (pre-RC) proteins in sensitive tumors. Accordingly, BET/MEK inhibitors suppress pre-RC proteins in cycling cells, triggering stalled replication, DNA damage, and death. These studies reveal a promising therapeutic strategy for KRAS-mutant NSCLCs, identify a predictive biomarker of response, and define a subset of NSCLCs with a targetable epigenetic vulnerability.
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Carcinoma de Pulmón de Células no Pequeñas/patología , Epigénesis Genética , Proteínas de Homeodominio/metabolismo , Neoplasias Pulmonares/patología , Mutación , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas p21(ras)/genética , Acrilonitrilo/análogos & derivados , Acrilonitrilo/farmacología , Compuestos de Anilina/farmacología , Animales , Apoptosis , Biomarcadores de Tumor/genética , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/genética , Proliferación Celular , Femenino , Regulación Neoplásica de la Expresión Génica , Proteínas de Homeodominio/genética , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , MAP Quinasa Quinasa 1/antagonistas & inhibidores , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Proteínas/antagonistas & inhibidores , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
PURPOSE: Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas. Combining Hsp90 inhibitors to enhance endoplasmic reticulum stress with mTOR inhibition results in dramatic MPNST shrinkage in a genetically engineered MPNST mouse model. Ganetespib is an injectable potent small molecule inhibitor of Hsp90. Sirolimus is an oral mTOR inhibitor. We sought to determine the safety, tolerability, and recommended dose of ganetespib and sirolimus in patients with refractory sarcomas and assess clinical benefits in patients with unresectable/refractory MPNSTs. Patients and Methods. In this multi-institutional, open-label, phase 1/2 study of ganetespib and sirolimus, patients ≥16 years with histologically confirmed refractory sarcoma (phase 1) or MPNST (phase 2) were eligible. A conventional 3 + 3 dose escalation design was used for phase 1. Pharmacokinetic and pharmacodynamic measures were evaluated. Primary objectives of phase 2 were to determine the clinical benefit rate (CBR) of this combination in MPNSTs. Patient-reported outcomes assessed pain. RESULTS: Twenty patients were enrolled (10 per phase). Toxicities were manageable; most frequent non-DLTs were diarrhea, elevated liver transaminases, and fatigue. The recommended dose of ganetespib was 200 mg/m2 intravenously on days 1, 8, and 15 with sirolimus 4 mg orally once daily with day 1 loading dose of 12 mg. In phase 1, one patient with leiomyosarcoma achieved a sustained partial response. In phase 2, no responses were observed. The median number of cycles treated was 2 (1-4). Patients did not meet the criteria for clinical benefit as defined per protocol. Pain ratings decreased or were stable. CONCLUSION: Despite promising preclinical rationale and tolerability of the combination therapy, no responses were observed, and the study did not meet parameters for further evaluation in MPNSTs. This trial was registered with (NCT02008877).
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Although the majority of BRAF-mutant melanomas respond to BRAF/MEK inhibitors, these agents are not typically curative. Moreover, they are largely ineffective in NRAS- and NF1-mutant tumors. Here we report that genetic and chemical suppression of HDAC3 potently cooperates with MAPK pathway inhibitors in all three RAS pathway-driven tumors. Specifically, we show that entinostat dramatically enhances tumor regression when combined with BRAF/MEK inhibitors, in both models that are sensitive or relatively resistant to these agents. Interestingly, MGMT expression predicts responsiveness and marks tumors with latent defects in DNA repair. BRAF/MEK inhibitors enhance these defects by suppressing homologous recombination genes, inducing a BRCA-like state; however, addition of entinostat triggers the concomitant suppression of nonhomologous end-joining genes, resulting in a chemical synthetic lethality caused by excessive DNA damage. Together, these studies identify melanomas with latent DNA repair defects, describe a promising drug combination that capitalizes on these defects, and reveal a tractable therapeutic biomarker. SIGNIFICANCE: BRAF/MEK inhibitors are not typically curative in BRAF-mutant melanomas and are ineffective in NRAS- and NF1-mutant tumors. We show that HDAC inhibitors dramatically enhance the efficacy of BRAF/MEK inhibitors in sensitive and insensitive RAS pathway-driven melanomas by coordinately suppressing two DNA repair pathways, and identify a clinical biomarker that predicts responsiveness.See related commentary by Lombard et al., p. 469.This article is highlighted in the In This Issue feature, p. 453.
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Reparación del ADN/genética , Genes ras/genética , Quinasas Quinasa Quinasa PAM/genética , Melanoma/genética , Humanos , Proteínas Proto-Oncogénicas B-rafRESUMEN
Gross deletions of the NF1 gene at 17q11.2 belong to the group of 'genomic disorders' characterized by local sequence architecture that predisposes to genomic rearrangements. Segmental duplications within regions associated with genomic disorders are prone to non-allelic homologous recombination (NAHR), which mediates gross rearrangements. Copy number variants (CNVs) without obvious phenotypic consequences also occur frequently in regions of genomic disorders. In the NF1 gene region, putative CNVs have been reportedly detected by array comparative genomic hybridization (array CGH). These variants include duplications and deletions within the NF1 gene itself (CNV1) and a duplication that encompasses the SUZ12 gene, the distal NF1-REPc repeat and the RHOT1 gene (CNV2). To explore the possibility that these CNVs could have played a role in promoting deletion mutagenesis in type-1 deletions (the most common type of gross NF1 deletion), non-affected transmitting parents of patients with type-1 NF1 deletions were investigated by multiplex ligation-dependent probe amplification (MLPA). However, neither CNV1 nor CNV2 were detected. This would appear to exclude these variants as frequent mediators of NAHR giving rise to type-1 deletions. Using MLPA, we were also unable to confirm CNV1 in healthy controls as previously reported. We conclude that locus-specific techniques should be used to independently confirm putative CNVs, originally detected by array CGH, to avoid false-positive results. In one patient with an atypical deletion, a duplication in the region of CNV2 was noted. This duplication could have occurred concomitantly with the deletion as part of a complex rearrangement or may alternatively have preceded the deletion.
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Eliminación de Gen , Dosificación de Gen , Genes de Neurofibromatosis 1 , Variación Genética/genética , Adulto , Cromosomas Humanos , Femenino , Duplicación de Gen , Humanos , Patrón de Herencia , Masculino , Técnicas de Amplificación de Ácido Nucleico , PadresRESUMEN
Preclinical studies using genetically engineered mouse models (GEMM) have the potential to expedite the development of effective new therapies; however, they are not routinely integrated into drug development pipelines. GEMMs may be particularly valuable for investigating treatments for less common cancers, which frequently lack alternative faithful models. Here, we describe a multicenter cooperative group that has successfully leveraged the expertise and resources from philanthropic foundations, academia, and industry to advance therapeutic discovery and translation using GEMMs as a preclinical platform. This effort, known as the Neurofibromatosis Preclinical Consortium (NFPC), was established to accelerate new treatments for tumors associated with neurofibromatosis type 1 (NF1). At its inception, there were no effective treatments for NF1 and few promising approaches on the horizon. Since 2008, participating laboratories have conducted 95 preclinical trials of 38 drugs or combinations through collaborations with 18 pharmaceutical companies. Importantly, these studies have identified 13 therapeutic targets, which have inspired 16 clinical trials. This review outlines the opportunities and challenges of building this type of consortium and highlights how it can accelerate clinical translation. We believe that this strategy of foundation-academic-industry partnering is generally applicable to many diseases and has the potential to markedly improve the success of therapeutic development. Cancer Res; 77(21); 5706-11. ©2017 AACR.
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Modelos Animales de Enfermedad , Descubrimiento de Drogas/métodos , Neoplasias/tratamiento farmacológico , Investigación Biomédica Traslacional/métodos , Animales , Humanos , Ratones , Terapia Molecular Dirigida/métodos , Neoplasias/complicaciones , Neoplasias/diagnóstico , Neurofibromatosis 1/complicaciones , Neurofibromatosis 1/diagnóstico , Neurofibromatosis 1/tratamiento farmacológicoRESUMEN
Luminal breast cancers are typically estrogen receptor-positive and generally have the best prognosis. However, a subset of luminal tumors, namely luminal B cancers, frequently metastasize and recur. Unfortunately, the causal events that drive their progression are unknown, and therefore it is difficult to identify individuals who are likely to relapse and should receive escalated treatment. Here, we identify a bifunctional RasGAP tumor suppressor whose expression is lost in almost 50% of luminal B tumors. Moreover, we show that two RasGAP genes are concomitantly suppressed in the most aggressive luminal malignancies. Importantly, these genes cooperatively regulate two major oncogenic pathways, RAS and NF-κB, through distinct domains, and when inactivated drive the metastasis of luminal tumors in vivo Finally, although the cooperative effects on RAS drive invasion, NF-κB activation triggers epithelial-to-mesenchymal transition and is required for metastasis. Collectively, these studies reveal important mechanistic insight into the pathogenesis of luminal B tumors and provide functionally relevant prognostic biomarkers that may guide treatment decisions. SIGNIFICANCE: The lack of insight into mechanisms that underlie the aggressive behavior of luminal B breast cancers impairs treatment decisions and therapeutic advances. Here, we show that two RasGAP tumor suppressors are concomitantly suppressed in aggressive luminal B tumors and demonstrate that they drive metastasis by activating RAS and NF-κB. Cancer Discov; 7(2); 202-17. ©2016 AACR.See related commentary by Sears and Gray, p. 131This article is highlighted in the In This Issue feature, p. 115.
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Neoplasias de la Mama/patología , Proteínas Portadoras/genética , FN-kappa B/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Proteínas Activadoras de ras GTPasa/genética , Animales , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Proteínas Portadoras/metabolismo , Línea Celular Tumoral , Progresión de la Enfermedad , Transición Epitelial-Mesenquimal , Femenino , Proteínas Activadoras de GTPasa , Humanos , Células MCF-7 , Ratones , Mutación , Metástasis de la Neoplasia , Trasplante de Neoplasias , Transducción de Señal , Proteínas Activadoras de ras GTPasa/metabolismoRESUMEN
Neurofibromatosis type 1 (NF1) is mainly characterized by the occurrence of benign peripheral nerve sheath tumors or neurofibromas. Thorough investigation of the somatic mutation spectrum has thus far been hampered by the large size of the NF1 gene and the considerable proportion of NF1 heterozygous cells within the tumors. We developed an improved somatic mutation detection strategy on cultured Schwann cells derived from neurofibromas and investigated 38 tumors from nine NF1 patients. Twenty-nine somatic NF1 lesions were detected which represents the highest NF1 somatic mutation detection rate described so far (76%). Furthermore, our data strongly suggest that the acquired second hit underlies reduced NF1 expression in Schwann cell cultures. Together, these data clearly illustrate that two inactivating NF1 mutations, in a subpopulation of the Schwann cells, are required for neurofibroma formation in NF1 tumorigenesis. The observed somatic mutation spectrum shows that intragenic NF1 mutations (26/29) are most prevalent, particularly frameshift mutations (12/29, 41%). We hypothesize that this mutation signature might reflect slightly reduced DNA repair efficiency as a trigger for NF1 somatic inactivation preceding tumorigenesis. Joint analysis of the current and previously published NF1 mutation data revealed a significant difference in the somatic mutation spectrum in patients with a NF1 microdeletion vs. non-microdeletion patients with respect to the prevalence of loss of heterozygosity events (0/15 vs. 41/81). Differences in somatic inactivation mechanism might therefore exist between NF1 microdeletion patients and the general NF1 population.
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Mutación/genética , Neurofibromina 1/genética , Células de Schwann/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Proteínas Portadoras/genética , Análisis Mutacional de ADN/métodos , Reparación del ADN/genética , Proteínas de Unión al ADN/genética , Mutación de Línea Germinal/genética , Humanos , Pérdida de Heterocigocidad , Repeticiones de Microsatélite/genética , Homólogo 1 de la Proteína MutL , Proteína 2 Homóloga a MutS/genética , Neurofibroma/genética , Neurofibroma/patología , Neurofibromatosis 1/genética , Neurofibromatosis 1/patología , Proteínas Nucleares/genética , Reacción en Cadena de la Polimerasa , ARN Mensajero/genética , ARN Mensajero/metabolismo , Eliminación de Secuencia , Células Tumorales CultivadasRESUMEN
UNLABELLED: As a master regulator of chromatin function, the lysine methyltransferase EZH2 orchestrates transcriptional silencing of developmental gene networks. Overexpression of EZH2 is commonly observed in human epithelial cancers, such as non-small cell lung carcinoma (NSCLC), yet definitive demonstration of malignant transformation by deregulated EZH2 remains elusive. Here, we demonstrate the causal role of EZH2 overexpression in NSCLC with new genetically engineered mouse models of lung adenocarcinoma. Deregulated EZH2 silences normal developmental pathways, leading to epigenetic transformation independent of canonical growth factor pathway activation. As such, tumors feature a transcriptional program distinct from KRAS- and EGFR-mutant mouse lung cancers, but shared with human lung adenocarcinomas exhibiting high EZH2 expression. To target EZH2-dependent cancers, we developed a potent open-source EZH2 inhibitor, JQEZ5, that promoted the regression of EZH2-driven tumors in vivo, confirming oncogenic addiction to EZH2 in established tumors and providing the rationale for epigenetic therapy in a subset of lung cancer. SIGNIFICANCE: EZH2 overexpression induces murine lung cancers that are similar to human NSCLC with high EZH2 expression and low levels of phosphorylated AKT and ERK, implicating biomarkers for EZH2 inhibitor sensitivity. Our EZH2 inhibitor, JQEZ5, promotes regression of these tumors, revealing a potential role for anti-EZH2 therapy in lung cancer. Cancer Discov; 6(9); 1006-21. ©2016 AACR.See related commentary by Frankel et al., p. 949This article is highlighted in the In This Issue feature, p. 932.
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Proteína Potenciadora del Homólogo Zeste 2/genética , Regulación Neoplásica de la Expresión Génica , Neoplasias Pulmonares/genética , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Cromatina/genética , Cromatina/metabolismo , Modelos Animales de Enfermedad , Diseño de Fármacos , Elementos de Facilitación Genéticos , Proteína Potenciadora del Homólogo Zeste 2/antagonistas & inhibidores , Proteína Potenciadora del Homólogo Zeste 2/metabolismo , Expresión Génica , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/metabolismo , Imagen por Resonancia Magnética , Ratones , Modelos Moleculares , Conformación Molecular , Terapia Molecular Dirigida , Regiones Promotoras Genéticas , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de XenoinjertoAsunto(s)
Bancos de Muestras Biológicas , Neoplasias Encefálicas , Bases de Datos Genéticas , Glioma , Niño , Femenino , Humanos , MasculinoRESUMEN
PURPOSE: The hallmark of neurofibromatosis type 1 (NF1) is the onset of dermal or plexiform neurofibromas, mainly composed of Schwann cells. Plexiform neurofibromas can transform into malignant peripheral nerve sheath tumors (MPNST) that are resistant to therapies. EXPERIMENTAL DESIGN: The aim of this study was to identify an additional pathway in the NF1 tumorigenesis. We focused our work on Wnt signaling that is highly implicated in cancer, mainly in regulating the proliferation of cancer stem cells. We quantified mRNAs of 89 Wnt pathway genes in 57 NF1-associated tumors including dermal and plexiform neurofibromas and MPNSTs. Expression of two major stem cell marker genes and five major epithelial-mesenchymal transition marker genes was also assessed. The expression of significantly deregulated Wnt genes was then studied in normal human Schwann cells, fibroblasts, endothelial cells, and mast cells and in seven MPNST cell lines. RESULTS: The expression of nine Wnt genes was significantly deregulated in plexiform neurofibromas in comparison with dermal neurofibromas. Twenty Wnt genes showed altered expression in MPNST biopsies and cell lines. Immunohistochemical studies confirmed the Wnt pathway activation in NF1-associated MPNSTs. We then confirmed that the knockdown of NF1 in Schwann cells but not in epithelial cells provoked the activation of Wnt pathway by functional transfection assays. Furthermore, we showed that the protein expression of active ß-catenin was increased in NF1-silenced cell lines. Wnt pathway activation was strongly associated to both cancer stem cell reservoir and Schwann-mesenchymal transition. CONCLUSION: We highlighted the implication of Wnt pathway in NF1-associated tumorigenesis.
Asunto(s)
Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Neurofibromatosis 1/genética , Neurofibromatosis 1/metabolismo , Vía de Señalización Wnt , Biomarcadores/metabolismo , Línea Celular Tumoral , Células Endoteliales/metabolismo , Transición Epitelial-Mesenquimal , Fibroblastos/metabolismo , Expresión Génica , Perfilación de la Expresión Génica , Humanos , Inmunofenotipificación , Mastocitos/metabolismo , Neurofibroma/genética , Neurofibroma/metabolismo , Neurofibroma/patología , Neurofibromatosis 1/patología , Neurofibromina 1/genética , Neurofibromina 1/metabolismo , ARN Mensajero/genética , Reproducibilidad de los Resultados , Células de Schwann/metabolismo , Células Madre/metabolismoRESUMEN
RAS genes are commonly mutated in cancer; however, RAS mutations are rare in breast cancer, despite frequent hyperactivation of Ras and ERK. Here, we report that the RasGAP gene, RASAL2, functions as a tumor and metastasis suppressor. RASAL2 is mutated or suppressed in human breast cancer, and RASAL2 ablation promotes tumor growth, progression, and metastasis in mouse models. In human breast cancer, RASAL2 loss is associated with metastatic disease; low RASAL2 levels correlate with recurrence of luminal B tumors; and RASAL2 ablation promotes metastasis of luminal mouse tumors. Additional data reveal a broader role for RASAL2 inactivation in other tumor types. These studies highlight the expanding role of RasGAPs and reveal an alternative mechanism of activating Ras in cancer.