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Characterized by the accumulation of somatic mutations in blood cell lineages, clonal hematopoiesis of indeterminate potential (CHIP) is frequent in aging and involves the expansion of mutated hematopoietic stem and progenitor cells (HSC/Ps) that leads to an increased risk of hematologic malignancy. However, the risk factors that contribute to CHIP-associated clonal hematopoiesis (CH) are poorly understood. Obesity induces a proinflammatory state and fatty bone marrow (FBM), which may influence CHIP-associated pathologies. We analyzed exome sequencing and clinical data for 47,466 individuals with validated CHIP in the UK Biobank. CHIP was present in 5.8% of the study population and was associated with a significant increase in the waist-to-hip ratio (WHR). Mouse models of obesity and CHIP driven by heterozygosity of Tet2, Dnmt3a, Asxl1, and Jak2 resulted in exacerbated expansion of mutant HSC/Ps due in part to excessive inflammation. Our results show that obesity is highly associated with CHIP and that a proinflammatory state could potentiate the progression of CHIP to more significant hematologic neoplasia. The calcium channel blockers nifedipine and SKF-96365, either alone or in combination with metformin, MCC950, or anakinra (IL-1 receptor antagonist), suppressed the growth of mutant CHIP cells and partially restored normal hematopoiesis. Targeting CHIP-mutant cells with these drugs could be a potential therapeutic approach to treat CH and its associated abnormalities in individuals with obesity.
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Hematopoiese Clonal , Neoplasias Hematológicas , Animais , Camundongos , Humanos , Hematopoiese Clonal/genética , Hematopoese/genética , Células-Tronco Hematopoéticas/patologia , Inflamação/genética , Inflamação/patologia , Neoplasias Hematológicas/genética , Obesidade/complicações , Obesidade/genética , Obesidade/patologia , MutaçãoRESUMO
In the current issue of Cell Stem Cell, Bogeska et al. demonstrate that repeated exposures to inflammation cause indelible and specific functional compromise and accelerated aging of long-term hematopoietic stem cells (LT-HSCs). This study proposes the notion that the cumulative inflammatory events over the course of an organism's lifespan may irreversibly damage LT-HSCs.
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Envelhecimento , Células-Tronco Hematopoéticas , Humanos , InflamaçãoRESUMO
INTRODUCTION: Src homology-2-containing protein tyrosine phosphatase 2 (SHP2) is a ubiquitously expressed, non-receptor protein tyrosine phosphatase encoded by the PTPN11 gene. Gain-of-function (GOF) mutations in PTPN11 are associated with the development of various hematological malignancies and Noonan syndrome with multiple lentigines (NS-ML). Preclinical studies performed with allosteric SHP2 inhibitors and combination treatments of SHP2 inhibitors with inhibitors of downstream regulators (such as MEK, ERK, and PD-1/PD-L1) demonstrate improved antitumor benefits. However, the development of novel SHP2 inhibitors is necessary to improve the therapeutic strategies for hematological malignancies and tackle drug resistance and disease relapse. AREAS COVERED: This review examines the structure of SHP2, its function in various signaling cascades, the consequences of constitutive activation of SHP2 and potential therapeutic strategies to treat SHP2-driven hematological malignancies. EXPERT OPINION: While SHP2 inhibitors have exhibited promise in preclinical trials, numerous challenges remain in translation to the clinic, including drug resistance. Although PROTAC-based SHP2 degraders show better efficacy than SHP2 inhibitors, novel strategies need to be designed to improve SHP2-specific therapies in hematologic malignancies. Genome-wide CRISPR screening should also be used to identify molecules that confer resistance to SHP2 inhibitors. Targeting these molecules together with SHP2 can increase the target specificity and reduce drug resistance.
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Neoplasias Hematológicas , Proteína Tirosina Fosfatase não Receptora Tipo 11 , Neoplasias Hematológicas/tratamento farmacológico , Neoplasias Hematológicas/genética , Humanos , Mutação , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Transdução de SinaisRESUMO
OBJECTIVES: Two pilot studies of AR-42, a pan-histone deacetylase inhibitor, in human neurofibromatosis type 2 (NF2), vestibular schwannomas (VS), and meningiomas are presented. Primary endpoints included safety, and intra-tumoral pharmacokinetics (PK) and pharmacodynamics (PD). METHODS: Pilot 1 is a subset analysis of a phase 1 study of AR-42 in solid tumors, which included NF2 or sporadic meningiomas. Tumor volumes and treatment-related adverse events (TRAEs) are reported (NCT01129193).Pilot 2 is a phase 0 surgical study of AR-42 assessing intra-tumoral PK and PD. AR-42 was administered for 3 weeks pre-operatively. Plasma and tumor drug concentrations and p-AKT expression were measured (NCT02282917). RESULTS: Pilot 1: Five patients with NF2 and two with sporadic meningiomas experienced a similar incidence of TRAEs to the overall phase I trial. The six evaluable patients had 15 tumors (8 VS, 7 meningiomas). On AR-42, tumor volume increased in six, remained stable in eight, and decreased in one tumor. The annual percent growth rate decreased in eight, remained stable in three, and increased in four tumors. Pilot 2: Four patients with sporadic VS and one patient with meningioma experienced no grade 3/4 toxicities. Expression of p-AKT decreased in three of four VS. All tumors had higher AR-42 concentrations than plasma. CONCLUSIONS: AR-42 is safe. Tumor volumes showed a mixed response, but most slowed growth. On a 40-mg regimen, drug concentrated in tumors and growth pathways were suppressed in most tumors, suggesting this may be a well-tolerated and effective dose. A phase 2 study of AR-42 for NF2-associated tumors appears warranted. LEVEL OF EVIDENCE: 1b, 4.
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Neurofibromatosis Type 2 (NF2) is an autosomal dominant genetic syndrome caused by mutations in the NF2 tumor suppressor gene resulting in multiple schwannomas and meningiomas. There are no FDA approved therapies for these tumors and their relentless progression results in high rates of morbidity and mortality. Through a combination of high throughput screens, preclinical in vivo modeling, and evaluation of the kinome en masse, we identified actionable drug targets and efficacious experimental therapeutics for the treatment of NF2 related schwannomas and meningiomas. These efforts identified brigatinib (ALUNBRIG®), an FDA-approved inhibitor of multiple tyrosine kinases including ALK, to be a potent inhibitor of tumor growth in established NF2 deficient xenograft meningiomas and a genetically engineered murine model of spontaneous NF2 schwannomas. Surprisingly, neither meningioma nor schwannoma cells express ALK. Instead, we demonstrate that brigatinib inhibited multiple tyrosine kinases, including EphA2, Fer and focal adhesion kinase 1 (FAK1). These data demonstrate the power of the de novo unbiased approach for drug discovery and represents a major step forward in the advancement of therapeutics for the treatment of NF2 related malignancies.
Assuntos
Neoplasias Meníngeas/genética , Meningioma/genética , Neurilemoma/genética , Neurofibromina 2/deficiência , Neurofibromina 2/genética , Compostos Organofosforados/farmacologia , Proteínas Tirosina Quinases/antagonistas & inibidores , Pirimidinas/farmacologia , Proliferação de Células , Humanos , Mutação , Neurilemoma/patologiaRESUMO
Hematopoietic stem cell transplantation (HSCT) is a critical treatment modality for many hematological and non-hematological diseases that is being extended to treat older individuals. However, recent studies show that clonal hematopoiesis of indeterminate potential (CHIP), a common, asymptomatic condition characterized by the expansion of age-acquired somatic mutations in blood cell lineages, may be a risk factor for the development of donor-derived leukemia (DDL), unexplained cytopenias, and chronic graft-versus-host disease. CHIP may contribute to the pathogenesis of these significant transplant complications via various cell-autonomous and non-cell-autonomous mechanisms, and the clinical presentation of DDL may be broader than anticipated. A more comprehensive understanding of the contributions of CHIP to DDL may have important implications for the screening of donors and will improve the safety of HSCT. The objective of this review is to discuss studies linking DDL and CHIP and to explore potential mechanisms by which CHIP may contribute to DDL.
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Hematopoiese Clonal , Leucemia/patologia , Doadores de Tecidos , Transplante de Células-Tronco Hematopoéticas , Humanos , Modelos Biológicos , Fatores de RiscoRESUMO
Characterized by the expansion of somatic mutations in the hematopoietic lineages of aging individuals, clonal hematopoiesis of indeterminate potential (CHIP) is a common condition that increases the risk of developing hematological malignancies and cardiovascular disease (CVD). The presence of CHIP-associated mutations in hematopoietic stem and progenitor cells (HSPCs) suggests that these mutations may alter the functions of the diverse hematopoietic lineages, many of which influence the pathogenesis of CVD. Inflammation may be a potential pathogenic mechanism, linking both CVD and hematological malignancy. However, it remains unknown whether CHIP-associated CVD and hematological malignancy are features of a common disease spectrum. The contributions of CHIP-associated mutations to both CVD and hematological malignancy underscore the importance of stem cell biology in pathogenesis and treatment. This review discusses possible mechanisms underlying the contributions of multiple hematopoietic lineages to CHIP-associated CVD and the putative pathogenic links between CHIP-associated CVD and hematological malignancy.
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Doenças Cardiovasculares/patologia , Hematopoiese Clonal , Linhagem da Célula , Epigênese Genética , Humanos , Inflamação/genética , Inflamação/patologia , Modelos BiológicosRESUMO
Studies of patients with acute myeloid leukemia (AML) have led to the identification of mutations that affect different cellular pathways. Some of these have been classified as preleukemic, and a stepwise evolution program whereby cells acquire additional mutations has been proposed in the development of AML. How the timing of acquisition of these mutations and their impact on transformation and the bone marrow (BM) microenvironment occurs has only recently begun to be investigated. We show that constitutive and early loss of the epigenetic regulator, TET2, when combined with constitutive activation of FLT3, results in transformation of chronic myelomonocytic leukemia-like or myeloproliferative neoplasm-like phenotype to AML, which is more pronounced in double-mutant mice relative to mice carrying mutations in single genes. Furthermore, we show that in preleukemic and leukemic mice there are alterations in the BM niche and secreted cytokines, which creates a permissive environment for the growth of mutation-bearing cells relative to normal cells.
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Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Mutação/genética , Animais , Células da Medula Óssea/metabolismo , Diferenciação Celular , Proliferação de Células , Citocinas/metabolismo , Proteínas de Ligação a DNA/metabolismo , Dioxigenases , Heterozigoto , Homozigoto , Humanos , Mediadores da Inflamação/metabolismo , Camundongos Endogâmicos C57BL , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Proteínas Proto-Oncogênicas/metabolismo , Índice de Gravidade de Doença , Microambiente Tumoral , Tirosina Quinase 3 Semelhante a fms/metabolismoRESUMO
Malignant peripheral nerve sheath tumors (MPNST) frequently overexpress eukaryotic initiation factor 4F components, and the eIF4A inhibitor silvestrol potently suppresses MPNST growth. However, silvestrol has suboptimal drug-like properties, including a bulky structure, poor oral bioavailability (<2%), sensitivity to MDR1 efflux, and pulmonary toxicity in dogs. We compared ten silvestrol-related rocaglates lacking the dioxanyl ring and found that didesmethylrocaglamide (DDR) and rocaglamide (Roc) had growth-inhibitory activity comparable with silvestrol. Structure-activity relationship analysis revealed that the dioxanyl ring present in silvestrol was dispensable for, but may enhance, cytotoxicity. Both DDR and Roc arrested MPNST cells at G2-M, increased the sub-G1 population, induced cleavage of caspases and PARP, and elevated the levels of the DNA-damage response marker γH2A.X, while decreasing the expression of AKT and ERK1/2, consistent with translation inhibition. Unlike silvestrol, DDR and Roc were not sensitive to MDR1 inhibition. Pharmacokinetic analysis confirmed that Roc had 50% oral bioavailability. Importantly, Roc, when administered intraperitoneally or orally, showed potent antitumor effects in an orthotopic MPNST mouse model and did not induce pulmonary toxicity in dogs as found with silvestrol. Treated tumors displayed degenerative changes and had more cleaved caspase-3-positive cells, indicative of increased apoptosis. Furthermore, Roc effectively suppressed the growth of osteosarcoma, Ewing sarcoma, and rhabdomyosarcoma cells and patient-derived xenografts. Both Roc- and DDR-treated sarcoma cells showed decreased levels of multiple oncogenic kinases, including insulin-like growth factor-1 receptor. The more favorable drug-like properties of DDR and Roc and the potent antitumor activity of Roc suggest that these rocaglamides could become viable treatments for MPNST and other sarcomas.
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Antineoplásicos Fitogênicos/farmacologia , Benzofuranos/química , Benzofuranos/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Neurofibrossarcoma/tratamento farmacológico , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Aglaia/química , Animais , Apoptose , Caspase 3/metabolismo , Ciclo Celular , Proliferação de Células , Humanos , Camundongos , Neurofibrossarcoma/metabolismo , Neurofibrossarcoma/patologia , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Meningiomas frequently display activation of the PI3K/AKT/mTOR pathway, leading to elevated levels of phospho-eukaryotic translation initiation factor 4E binding proteins, which enhances protein synthesis; however, it is not known whether inhibition of protein translation is an effective treatment option for meningiomas. We found that human meningiomas expressed high levels of the three components of the eukaryotic initiation factor 4F (eIF4F) translation initiation complex, eIF4A, eIF4E, and eIF4G. The expression of eIF4A and eIF4E was important in sustaining the growth of NF2-deficient benign meningioma Ben-Men-1 cells, as shRNA-mediated knockdown of these proteins strongly reduced cell proliferation. Among a series of 23 natural compounds evaluated, silvestrol, which inhibits eIF4A, was identified as being the most growth inhibitory in both primary meningioma and Ben-Men-1 cells. Silvestrol treatment of meningioma cells prominently induced G2/M arrest. Consistently, silvestrol significantly decreased the amounts of cyclins D1, E1, A, and B, PCNA, and Aurora A. In addition, total and phosphorylated AKT, ERK, and FAK, which have been shown to be important drivers for meningioma cell proliferation, were markedly lower in silvestrol-treated Ben-Men-1 cells. Our findings suggest that inhibiting protein translation could be a potential treatment for meningiomas.
Assuntos
Antineoplásicos/farmacologia , Fator de Iniciação 4A em Eucariotos/biossíntese , Fator de Iniciação 4E em Eucariotos/biossíntese , Fator de Iniciação Eucariótico 4G/biossíntese , Neoplasias Meníngeas/tratamento farmacológico , Meningioma/tratamento farmacológico , Proteínas de Neoplasias/biossíntese , Iniciação Traducional da Cadeia Peptídica/efeitos dos fármacos , Triterpenos/farmacologia , Antineoplásicos/uso terapêutico , Aurora Quinase A/biossíntese , Aurora Quinase A/genética , Ciclinas/biossíntese , Ciclinas/genética , Ensaios de Seleção de Medicamentos Antitumorais , Fator de Iniciação 4A em Eucariotos/antagonistas & inibidores , Fator de Iniciação 4A em Eucariotos/genética , Fator de Iniciação 4E em Eucariotos/genética , Fator de Iniciação Eucariótico 4G/genética , Feminino , Fase G2/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Masculino , Neoplasias Meníngeas/genética , Neoplasias Meníngeas/patologia , Meningioma/genética , Meningioma/patologia , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/genética , Antígeno Nuclear de Célula em Proliferação/biossíntese , Antígeno Nuclear de Célula em Proliferação/genética , RNA Interferente Pequeno/farmacologia , Triterpenos/uso terapêutico , Células Tumorais CultivadasRESUMO
Neurofibromatosis 2 (NF2) is a rare tumor suppressor syndrome that manifests with multiple schwannomas and meningiomas. There are no effective drug therapies for these benign tumors and conventional therapies have limited efficacy. Various model systems have been created and several drug targets have been implicated in NF2-driven tumorigenesis based on known effects of the absence of merlin, the product of the NF2 gene. We tested priority compounds based on known biology with traditional dose-concentration studies in meningioma and schwann cell systems. Concurrently, we studied functional kinome and gene expression in these cells pre- and post-treatment to determine merlin deficient molecular phenotypes. Cell viability results showed that three agents (GSK2126458, Panobinostat, CUDC-907) had the greatest activity across schwannoma and meningioma cell systems, but merlin status did not significantly influence response. In vivo, drug effect was tumor specific with meningioma, but not schwannoma, showing response to GSK2126458 and Panobinostat. In culture, changes in both the transcriptome and kinome in response to treatment clustered predominantly based on tumor type. However, there were differences in both gene expression and functional kinome at baseline between meningioma and schwannoma cell systems that may form the basis for future selective therapies. This work has created an openly accessible resource (www.synapse.org/SynodosNF2) of fully characterized isogenic schwannoma and meningioma cell systems as well as a rich data source of kinome and transcriptome data from these assay systems before and after treatment that enables single and combination drug discovery based on molecular phenotype.
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Neoplasias Meníngeas/genética , Neurilemoma/genética , Neurofibromatose 2/genética , Neurofibromina 2/genética , Animais , Carcinogênese/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Meníngeas/tratamento farmacológico , Neoplasias Meníngeas/patologia , Camundongos , Morfolinas/farmacologia , Neurilemoma/tratamento farmacológico , Neurilemoma/patologia , Neurofibromatose 2/tratamento farmacológico , Neurofibromatose 2/patologia , Panobinostat/farmacologia , Piridazinas , Pirimidinas/farmacologia , Quinolinas/farmacologia , Sulfonamidas/farmacologia , Biologia de Sistemas , Transcriptoma/genéticaRESUMO
Neurofibromatosis type 2 (NF2) is a nervous system tumor disorder caused by inactivation of the merlin tumor suppressor encoded by the NF2 gene. Bilateral vestibular schwannomas are a diagnostic hallmark of NF2. Mainstream treatment options for NF2-associated tumors have been limited to surgery and radiotherapy; however, off-label uses of targeted molecular therapies are becoming increasingly common. Here, we investigated drugs targeting two kinases activated in NF2-associated schwannomas, c-Met and Src. We demonstrated that merlin-deficient mouse Schwann cells (MD-MSC) treated with the c-Met inhibitor, cabozantinib, or the Src kinase inhibitors, dasatinib and saracatinib, underwent a G1 cell-cycle arrest. However, when MD-MSCs were treated with a combination of cabozantinib and saracatinib, they exhibited caspase-dependent apoptosis. The combination therapy also significantly reduced growth of MD-MSCs in an orthotopic allograft mouse model by greater than 80% of vehicle. Moreover, human vestibular schwannoma cells with NF2 mutations had a 40% decrease in cell viability when treated with cabozantinib and saracatinib together compared with the vehicle control. This study demonstrates that simultaneous inhibition of c-Met and Src signaling in MD-MSCs triggers apoptosis and reveals vulnerable pathways that could be exploited to develop NF2 therapies. Mol Cancer Ther; 16(11); 2387-98. ©2017 AACR.
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Neurilemoma/tratamento farmacológico , Neurofibromina 2/genética , Proteínas Proto-Oncogênicas c-met/genética , Quinases da Família src/genética , Anilidas/administração & dosagem , Animais , Apoptose/efeitos dos fármacos , Benzodioxóis/administração & dosagem , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Terapia Combinada , Dasatinibe/administração & dosagem , Humanos , Camundongos , Neurilemoma/genética , Neurilemoma/patologia , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Piridinas/administração & dosagem , Quinazolinas/administração & dosagem , Células de Schwann/efeitos dos fármacos , Células de Schwann/patologia , Ensaios Antitumorais Modelo de Xenoenxerto , Quinases da Família src/antagonistas & inibidoresRESUMO
Schwannomas and meningiomas are nervous system tumors that can occur sporadically or in patients with neurofibromatosis type 2 (NF2). Mutations of the Neurofibromatosis 2 (NF2) gene are frequently observed in these tumors. Schwannomas and meningiomas cause significant morbidities, and an FDA-approved medical therapy is currently not available. The development of preclinical animal models that accurately capture the clinical characteristics of these tumors will facilitate the evaluation of novel therapeutic agents for the treatment of these tumors, ultimately leading to more productive clinical trials. Here, we describe the generation of luciferase-expressing NF2-deficient schwannoma and meningioma cells and the use of these cells to establish orthotopic tumor models in immunodeficient mice. The growth of these tumors and their response to treatment can be measured effectively by bioluminescence imaging (BLI) and confirmed by small-animal magnetic resonance imaging (MRI). These and other animal models, such as genetically-engineered models, should substantially advance the investigation of promising therapies for schwannomas and meningiomas.
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Modelos Animais de Doenças , Neoplasias Meníngeas/patologia , Meningioma/patologia , Neurilemoma/patologia , Neurofibromina 2/deficiência , Animais , Humanos , Luciferases/genética , Luciferases/metabolismo , Medições Luminescentes , Imageamento por Ressonância Magnética , Neoplasias Meníngeas/diagnóstico por imagem , Neoplasias Meníngeas/genética , Meningioma/diagnóstico por imagem , Meningioma/genética , Camundongos , Camundongos SCID , Mutação , Transplante de Neoplasias , Neurilemoma/diagnóstico por imagem , Neurilemoma/genética , Células Tumorais CultivadasRESUMO
BACKGROUND: The eukaryotic initiation factor 4F (eIF4F) complex plays a pivotal role in protein translation initiation; however, its importance in malignant and benign Schwann cell tumors has not been explored, and whether blocking eIF4F function is effective for treating these tumors is not known. METHODS: Immunostaining was performed on human malignant peripheral nerve sheath tumors (MPNSTs) and vestibular schwannomas (VSs) for eIF4F components. The role of eIF4A and eIF4E in cell growth was assessed by RNA interference. Various natural compounds were screened for their growth-inhibitory activity. Flow cytometry and Western blotting were performed to characterize the action of silvestrol, and its antitumor activity was verified in orthotopic mouse models. RESULTS: MPNSTs and VSs frequently overexpressed eIF4A, eIF4E, and/or eIF4G. Depletion of eIF4A1, eIF4A2, and eIF4E substantially reduced MPNST cell growth. From screening a panel of plant-derived compounds, the eIF4A inhibitor silvestrol was identified as a leading agent with nanomolar IC50 values in MPNST and VS cells. Silvestrol induced G2/M arrest in both NF1-deficient and NF1-expressing MPNST cells and primary VS cells. Silvestrol consistently decreased the levels of multiple cyclins, Aurora A, and mitogenic kinases AKT and ERKs. Silvestrol treatment dramatically suppressed tumor growth in mouse models for NF1(-/-) MPNST and Nf2(-/-) schwannoma. This decreased tumor growth was accompanied by elevated phospho-histone H3 and TUNEL labeling, consistent with G2/M arrest and apoptosis in silvestrol-treated tumor cells. CONCLUSIONS: The eIF4F complex is a potential therapeutic target in MPNSTs and VS, and silvestrol may be a promising agent for treating these tumors.
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Biomarcadores Tumorais/metabolismo , Fator de Iniciação 4A em Eucariotos/metabolismo , Fator de Iniciação 4E em Eucariotos/metabolismo , Fator de Iniciação 4F em Eucariotos/metabolismo , Fator de Iniciação Eucariótico 4G/metabolismo , Neurilemoma/metabolismo , Neuroma Acústico/metabolismo , Animais , Apoptose , Proliferação de Células , Fator de Iniciação 4A em Eucariotos/antagonistas & inibidores , Fator de Iniciação 4E em Eucariotos/antagonistas & inibidores , Fator de Iniciação 4F em Eucariotos/antagonistas & inibidores , Fator de Iniciação Eucariótico 4G/antagonistas & inibidores , Humanos , Camundongos , Neurilemoma/patologia , Neuroma Acústico/patologia , RNA Interferente Pequeno/genética , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
HYPOTHESIS: Cucurbitacin D and goyazensolide, 2 plant-derived natural compounds, possess potent growth-inhibitory activity in schwannoma and meningioma cells. BACKGROUND: Currently, no FDA-approved drugs are available for neurofibromatosis type 2 (NF2)-associated schwannomas and meningiomas. Selected natural compounds with antineoplastic activity, such as cucurbitacin D and goyazensolide, may be developed as potential treatments for these tumors. METHODS: The Nf2-deficient mouse schwannoma Sch10545 and human benign meningioma Ben-Men-1 cells were treated with various concentrations of cucurbitacin D and goyazensolide. The effect on cell proliferation was determined using resazurin assays. Flow cytometry was used to assess the cell cycle profiles. Western blot analysis was performed to investigate the expression of various signaling molecules related to the cell cycle and the AKT pathway. RESULTS: Cucurbitacin D inhibited proliferation of Sch10545 cells (IC50 â¼ 0.75 µM) and Ben-Men-1 cells (IC50 â¼0.2 µM). Goyazensolide also reduced cell proliferation of Sch10545 cells (IC50 â¼0.9 µM) and Ben-Men-1 cells (IC50 â¼1 µM). The G2/M population increased in both Sch10545 and Ben-Men-1 cells treated with cucurbitacin D or goyazensolide around the IC50. Cucurbitacin and goyazensolide substantially reduced the levels of cyclins E and A in treated Sch10545 and Ben-Men-1 cells. Cucurbitacin D also inhibited cyclin B, phospho-AKT and phospho-PRAS40 expression. In addition, goyazensolide reduced the levels of phospho-AKT and NFκB and increased the expression of pro-apoptotic Bim in Sch10545 and Ben-Men-1 cells. CONCLUSION: Both cucurbitacin D and goyazensolide effectively inhibit proliferation of NF2-deficient schwannoma and meningioma cells, suggesting that these natural compounds should be further evaluated as potential treatments for NF2-related tumors.
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Antineoplásicos/farmacologia , Hidrocarbonetos Aromáticos com Pontes/farmacologia , Proliferação de Células/efeitos dos fármacos , Furanos/farmacologia , Meningioma/tratamento farmacológico , Neurilemoma/tratamento farmacológico , Triterpenos/farmacologia , Animais , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Hidrocarbonetos Aromáticos com Pontes/uso terapêutico , Ciclo Celular/efeitos dos fármacos , Furanos/uso terapêutico , Células Hep G2 , Humanos , Neoplasias Meníngeas/tratamento farmacológico , Neoplasias Meníngeas/metabolismo , Neoplasias Meníngeas/patologia , Meningioma/metabolismo , Meningioma/patologia , Camundongos , Neurilemoma/metabolismo , Neurilemoma/patologia , Neurofibromina 2/metabolismo , Sesterterpenos , Triterpenos/uso terapêuticoRESUMO
Meningiomas constitute about 34% of primary intracranial tumors and are associated with increased mortality in patients with neurofibromatosis type 2 (NF2). To evaluate potential medical therapies for these tumors, we have established a quantifiable orthotopic model for NF2-deficient meningiomas. We showed that telomerase-immortalized Ben-Men-1 benign meningioma cells harbored a single nucleotide deletion in NF2 exon 7 and did not express the NF2 protein, merlin. We also showed that AR-42, a pan-histone deacetylase inhibitor, inhibited proliferation of both Ben-Men-1 and normal meningeal cells by increasing expression of p16(INK4A), p21(CIP1/WAF1), and p27(KIP1). In addition, AR-42 increased proapoptotic Bim expression and decreased anti-apoptotic Bcl(XL) levels. However, AR-42 predominantly arrested Ben-Men-1 cells at G(2)-M whereas it induced cell-cycle arrest at G(1) in meningeal cells. Consistently, AR-42 substantially decreased the levels of cyclin D1, E, and A, and proliferating cell nuclear antigen in meningeal cells while significantly reducing the expression of cyclin B, important for progression through G(2), in Ben-Men-1 cells. In addition, AR-42 decreased Aurora A and B expression. To compare the in vivo efficacies of AR-42 and AR-12, a PDK1 inhibitor, we generated and used luciferase-expressing Ben-Men-1-LucB cells to establish intracranial xenografts that grew over time. While AR-12 treatment moderately slowed tumor growth, AR-42 caused regression of Ben-Men-1-LucB tumors. Importantly, AR-42-treated tumors showed minimal regrowth when xenograft-bearing mice were switched to normal diet. Together, these results suggest that AR-42 is a potential therapy for meningiomas. The differential effect of AR-42 on cell-cycle progression of normal meningeal and meningioma cells may have implications for why AR-42 is well-tolerated while it potently inhibits tumor growth.
Assuntos
Genes da Neurofibromatose 2 , Inibidores de Histona Desacetilases/farmacologia , Neoplasias Meníngeas/genética , Meninges/efeitos dos fármacos , Meningioma/genética , Fenilbutiratos/farmacologia , Animais , Ciclo Celular/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Neoplasias Meníngeas/patologia , Meningioma/patologia , Camundongos , Camundongos SCID , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
HYPOTHESIS: Aberrant phosphorylation of ErbB family receptor tyrosine kinases (RTK) in human vestibular schwannomas (VSs) renders them susceptible to growth suppression by RTK inhibitors. BACKGROUND: Recent evidence has implicated increased ErbB family receptor tyrosine kinase signaling in VS tumorigenesis; however, the characterization of ErbB receptor activity and the chemotherapeutic potential of RTK inhibitors in VS treatment have not been fully explored. METHODS: To confirm phosphorylation of ErbB receptors in VS, protein extracts from paired VS tumor-vestibular nerve samples were examined using phospho-RTK arrays. ErbB receptor phosphorylation was similarly examined in cultured schwannoma cells, normal Schwann cells, and VS tumor tissues using Western blotting. Also, VS tumor sections were immunostained for members of the ErbB receptor family. The effects of RTK inhibitors on ErbB phosphorylation and cell proliferation were assessed in schwannoma cells after epidermal growth factor receptor (EGFR) inhibitor (Erlotinib) and EGFR/ErbB2 inhibitor (Lapatinib) treatment. RESULTS: VS tumor tissues consistently demonstrated higher levels of phosphorylated ErbB3 compared with paired vestibular nerves. However, cultured VS, malignant schwannoma, and normal Schwann cells demonstrated EGFR phosphorylation. Immunohistochemistry confirmed high expression of ErbB3 in a series of VS tumor sections. Erlotinib inhibited schwannoma cell proliferation with an IC50 value of 2.5 µmol/L, whereas Lapatinib was less potent for growth inhibition. Erlotinib treatment resulted in a decrease of multiple phospho-ErbB receptors in schwannoma cells. CONCLUSION: VS variably express activated ErbB receptors with consistently higher levels of phospho-ErbB3 expression relative to paired vestibular nerve samples. Chemotherapeutic targeting of ErbB3 may be a novel means of inhibiting VS growth.
Assuntos
Antineoplásicos/uso terapêutico , Neoplasias da Orelha/tratamento farmacológico , Neuroma Acústico/tratamento farmacológico , Proteínas Oncogênicas v-erbB/antagonistas & inibidores , Anticorpos Monoclonais/uso terapêutico , Antineoplásicos/farmacologia , Western Blotting , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Neoplasias da Orelha/patologia , Cloridrato de Erlotinib , Humanos , Imuno-Histoquímica , Lapatinib , Neuroma Acústico/patologia , Fosforilação , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Quinazolinas/farmacologia , Quinazolinas/uso terapêutico , Nervo Vestibular/patologiaRESUMO
Neurofibromatosis type 2 (NF2) is an autosomal-dominant disease that results in the formation of bilateral vestibular schwannomas (VSs) and multiple meningiomas. Treatment options for NF2-associated tumors are limited, and to date, no medical therapies are FDA approved. The ideal chemotherapeutic agent would inhibit both VS and meningiomas simultaneously. The objectives of this study are (1) to test the efficacy of AR42, a novel histone deacetylase inhibitor, to inhibit VS and meningioma growth and (2) to investigate this drug's mechanisms of action. Primary cultures of human VS and meningioma cells were established. Nf2-deficient mouse schwannoma and benign human meningioma Ben-Men-1 cells were also cultured. Cells were treated with AR42, and the drug's effects on proliferation and the cell cycle were analyzed using a methanethiosulfonate assay and flow cytometry, respectively. Human phospho-kinase arrays and Western blots were used to evaluate the effects of AR42 on intracellular signaling. The in vivo efficacy of AR42 was investigated using schwannoma xenografts. Tumor volumes were quantified using high-field, volumetric MRI, and molecular target analysis was performed using immunohistochemistry. AR42 inhibited the growth of primary human VS and Nf2-deficient mouse schwannoma cells with a half maximal inhibitory concentration (IC(50)) of 500 nM and 250-350 nM, respectively. AR42 also inhibited primary meningioma cells and the benign meningioma cell line, Ben-Men-1, with IC(50) values of 1.5 µM and 1.0 µM, respectively. AR42 treatment induced cell-cycle arrest at G(2) and apoptosis in both VS and meningioma cells. Also, AR42 exposure decreased phosphorylated Akt in schwannoma and meningioma cells. In vivo treatment with AR42 inhibited the growth of schwannoma xenografts, induced apoptosis, and decreased Akt activation. The potent growth inhibitory activity of AR42 in schwannoma and meningioma cells suggests that AR42 should be further evaluated as a potential treatment for NF2-associated tumors.
Assuntos
Inibidores de Histona Desacetilases/uso terapêutico , Neoplasias Meníngeas/tratamento farmacológico , Meningioma/tratamento farmacológico , Neuroma Acústico/tratamento farmacológico , Fenilbutiratos/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Imunofluorescência , Humanos , Técnicas Imunoenzimáticas , Imageamento por Ressonância Magnética , Neoplasias Meníngeas/metabolismo , Neoplasias Meníngeas/patologia , Meningioma/metabolismo , Meningioma/patologia , Camundongos , Camundongos Knockout , Camundongos SCID , Neurofibromatose 2/tratamento farmacológico , Neurofibromatose 2/metabolismo , Neurofibromatose 2/patologia , Neurofibromina 2/fisiologia , Neuroma Acústico/metabolismo , Neuroma Acústico/patologia , Fosforilação/efeitos dos fármacos , Análise Serial de Proteínas , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Taxa de SobrevidaRESUMO
Hepatocyte growth factor receptor tyrosine kinase substrate (HRS) is an endosomal protein required for trafficking receptor tyrosine kinases from the early endosome to the lysosome. HRS interacts with Merlin, the Neurofibromatosis 2 (NF2) gene product, and this interaction may be important for Merlin's tumor suppressor activity. Understanding the evolution, origin, and structure of HRS may provide new insight into Merlin function. We show that HRS homologs are present across a wide range of Metazoa with the yeast Vps27 protein as their most distant ancestor. The phylogenetic tree of the HRS family coincides with species evolution and divergence, suggesting a unique function for HRS. Sequence alignment shows that various protein domains of HRS, including the VHS domain, the FYVE domain, the UIM domain, and the clathrin-binding domain, are conserved from yeast to multicellular organisms. The evolutionary transition from unicellular to multicellular organisms was accompanied by the appearance of a binding site for Merlin, which emerges in the early Metazoa after its separation from flatworms. In addition to the region responsible for growth suppression, the Merlin-binding and STAM-binding domains of HRS are conserved among multicellular organisms. The residue equivalent to tyrosine-377, which is phosphorylated in the human HRS protein, is highly conserved throughout the HRS family. Three additional conserved boxes lacking assigned functions are found in the HRS proteins of Metazoa. While boxes 1 and 3 may constitute the Eps-15-and Snx1-binding sites, respectively, box 2, containing the residue equivalent to tyrosine-377, is likely to be important for HRS phosphorylation. While several functional domains are conserved throughout the HRS family, the STAM-binding, Merlin-binding, and growth suppression domains evolved in the early Metazoa around the time the Merlin protein emerged. As these domains appear during the transition to multicellularity, their functional roles may be related to cell-cell interaction.