RESUMO
BACKGROUND: Isocitrate dehydrogenase (IDH)-mutant grade 2 gliomas are malignant brain tumors that cause considerable disability and premature death. Vorasidenib, an oral brain-penetrant inhibitor of mutant IDH1 and IDH2 enzymes, showed preliminary activity in IDH-mutant gliomas. METHODS: In a double-blind, phase 3 trial, we randomly assigned patients with residual or recurrent grade 2 IDH-mutant glioma who had undergone no previous treatment other than surgery to receive either oral vorasidenib (40 mg once daily) or matched placebo in 28-day cycles. The primary end point was imaging-based progression-free survival according to blinded assessment by an independent review committee. The key secondary end point was the time to the next anticancer intervention. Crossover to vorasidenib from placebo was permitted on confirmation of imaging-based disease progression. Safety was also assessed. RESULTS: A total of 331 patients were assigned to receive vorasidenib (168 patients) or placebo (163 patients). At a median follow-up of 14.2 months, 226 patients (68.3%) were continuing to receive vorasidenib or placebo. Progression-free survival was significantly improved in the vorasidenib group as compared with the placebo group (median progression-free survival, 27.7 months vs. 11.1 months; hazard ratio for disease progression or death, 0.39; 95% confidence interval [CI], 0.27 to 0.56; P<0.001). The time to the next intervention was significantly improved in the vorasidenib group as compared with the placebo group (hazard ratio, 0.26; 95% CI, 0.15 to 0.43; P<0.001). Adverse events of grade 3 or higher occurred in 22.8% of the patients who received vorasidenib and in 13.5% of those who received placebo. An increased alanine aminotransferase level of grade 3 or higher occurred in 9.6% of the patients who received vorasidenib and in no patients who received placebo. CONCLUSIONS: In patients with grade 2 IDH-mutant glioma, vorasidenib significantly improved progression-free survival and delayed the time to the next intervention. (Funded by Servier; INDIGO ClinicalTrials.gov number, NCT04164901.).
Assuntos
Antineoplásicos , Glioma , Recidiva Local de Neoplasia , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Progressão da Doença , Método Duplo-Cego , Glioma/tratamento farmacológico , Glioma/genética , Isocitrato Desidrogenase/genética , Recidiva Local de Neoplasia/tratamento farmacológico , Piridinas/efeitos adversos , Antineoplásicos/uso terapêutico , Inibidores Enzimáticos/uso terapêuticoRESUMO
Diffuse gliomas are the most common malignant brain tumours in adults and include glioblastomas and World Health Organization (WHO) grade II and grade III tumours (sometimes referred to as lower-grade gliomas). Genetic tumour profiling is used to classify disease and guide therapy1,2, but involves brain surgery for tissue collection; repeated tumour biopsies may be necessary for accurate genotyping over the course of the disease3-10. While the detection of circulating tumour DNA (ctDNA) in the blood of patients with primary brain tumours remains challenging11,12, sequencing of ctDNA from the cerebrospinal fluid (CSF) may provide an alternative way to genotype gliomas with lower morbidity and cost13,14. We therefore evaluated the representation of the glioma genome in CSF from 85 patients with gliomas who underwent a lumbar puncture because they showed neurological signs or symptoms. Here we show that tumour-derived DNA was detected in CSF from 42 out of 85 patients (49.4%) and was associated with disease burden and adverse outcome. The genomic landscape of glioma in the CSF included a broad spectrum of genetic alterations and closely resembled the genomes of tumour biopsies. Alterations that occur early during tumorigenesis, such as co-deletion of chromosome arms 1p and 19q (1p/19q codeletion) and mutations in the metabolic genes isocitrate dehydrogenase 1 (IDH1) or IDH21,2, were shared in all matched ctDNA-positive CSF-tumour pairs, whereas growth factor receptor signalling pathways showed considerable evolution. The ability to monitor the evolution of the glioma genome through a minimally invasive technique could advance the clinical development and use of genotype-directed therapies for glioma, one of the most aggressive human cancers.
Assuntos
Evolução Molecular , Glioma/líquido cefalorraquidiano , Glioma/genética , Biópsia Líquida , Mutação , Genes Neoplásicos/genética , Genoma Humano/genética , Genômica , Glioblastoma/líquido cefalorraquidiano , Glioblastoma/genética , Glioblastoma/patologia , Glioma/patologia , Humanos , Gradação de TumoresRESUMO
Small-molecule kinase inhibitors represent a major group of cancer therapeutics, but tumor responses are often incomplete. To identify pathways that modulate kinase inhibitor response, we conducted a genome-wide knockout (KO) screen in glioblastoma cells treated with the pan-ErbB inhibitor neratinib. Loss of general control nonderepressible 2 (GCN2) kinase rendered cells resistant to neratinib, whereas depletion of the GADD34 phosphatase increased neratinib sensitivity. Loss of GCN2 conferred neratinib resistance by preventing binding and activation of GCN2 by neratinib. Several other Food and Drug Administration (FDA)-approved inhibitors, such erlotinib and sunitinib, also bound and activated GCN2. Our results highlight the utility of genome-wide functional screens to uncover novel mechanisms of drug action and document the role of the integrated stress response (ISR) in modulating the response to inhibitors of oncogenic kinases.
Assuntos
Trifosfato de Adenosina/metabolismo , Antineoplásicos/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Quinolinas/farmacologia , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Sistemas de Liberação de Medicamentos , Deleção de Genes , Glioblastoma/tratamento farmacológico , Humanos , Inibidores de Proteínas Quinases/químicaRESUMO
Importance: Malignant primary brain tumors cause more than 15â¯000 deaths per year in the United States. The annual incidence of primary malignant brain tumors is approximately 7 per 100â¯000 individuals and increases with age. Five-year survival is approximately 36%. Observations: Approximately 49% of malignant brain tumors are glioblastomas, and 30% are diffusely infiltrating lower-grade gliomas. Other malignant brain tumors include primary central nervous system (CNS) lymphoma (7%) and malignant forms of ependymomas (3%) and meningiomas (2%). Symptoms of malignant brain tumors include headache (50%), seizures (20%-50%), neurocognitive impairment (30%-40%), and focal neurologic deficits (10%-40%). Magnetic resonance imaging before and after a gadolinium-based contrast agent is the preferred imaging modality for evaluating brain tumors. Diagnosis requires tumor biopsy with consideration of histopathological and molecular characteristics. Treatment varies by tumor type and often includes a combination of surgery, chemotherapy, and radiation. For patients with glioblastoma, the combination of temozolomide with radiotherapy improved survival when compared with radiotherapy alone (2-year survival, 27.2% vs 10.9%; 5-year survival, 9.8% vs 1.9%; hazard ratio [HR], 0.6 [95% CI, 0.5-0.7]; P < .001). In patients with anaplastic oligodendroglial tumors with 1p/19q codeletion, probable 20-year overall survival following radiotherapy without vs with the combination of procarbazine, lomustine, and vincristine was 13.6% vs 37.1% (80 patients; HR, 0.60 [95% CI, 0.35-1.03]; P = .06) in the EORTC 26951 trial and 14.9% vs 37% in the RTOG 9402 trial (125 patients; HR, 0.61 [95% CI, 0.40-0.94]; P = .02). Treatment of primary CNS lymphoma includes high-dose methotrexate-containing regimens, followed by consolidation therapy with myeloablative chemotherapy and autologous stem cell rescue, nonmyeloablative chemotherapy regimens, or whole brain radiation. Conclusions and Relevance: The incidence of primary malignant brain tumors is approximately 7 per 100â¯000 individuals, and approximately 49% of primary malignant brain tumors are glioblastomas. Most patients die from progressive disease. First-line therapy for glioblastoma is surgery followed by radiation and the alkylating chemotherapeutic agent temozolomide.
Assuntos
Neoplasias Encefálicas , Glioblastoma , Adulto , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Encéfalo/patologia , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/epidemiologia , Neoplasias Encefálicas/terapia , Glioblastoma/diagnóstico , Glioblastoma/epidemiologia , Glioblastoma/terapia , Glioma/diagnóstico , Glioma/epidemiologia , Glioma/terapia , Linfoma/diagnóstico , Linfoma/epidemiologia , Linfoma/terapia , Temozolomida/uso terapêuticoRESUMO
BACKGROUND: High-dose methotrexate (HD-MTX) has broad use in the treatment of central nervous system (CNS) malignancies but confers significant toxicity without inpatient hydration and monitoring. Glucarpidase is a bacterial recombinant enzyme dosed at 50 units (u)/kg, resulting in rapid systemic MTX clearance. The aim of this study was to demonstrate feasibility of low-dose glucarpidase to facilitate MTX clearance in patients with CNS lymphoma (CNSL). METHODS: Eight CNSL patients received HD-MTX 3 or 6 g/m2 and glucarpidase 2000 or 1000u 24 h later. Treatments repeated every 2 weeks up to 8 cycles. RESULTS: Fifty-five treatments were administered. Glucarpidase 2000u yielded > 95% reduction in plasma MTX within 15 min following 33/34 doses (97.1%) and glucarpidase 1000u yielded > 95% reduction following 15/20 doses (75%). Anti-glucarpidase antibodies developed in 4 patients and were associated with MTX rebound. In CSF, glucarpidase was not detected and MTX levels remained cytotoxic after 1 (3299.5 nmol/L, n = 8) and 6 h (1254.7 nmol/L, n = 7). Treatment was safe and well-tolerated. Radiographic responses in 6 of 8 patients (75%) were as expected following MTX-based therapy. CONCLUSIONS: This study demonstrates feasibility of planned-use low-dose glucarpidase for MTX clearance and supports the hypothesis that glucarpidase does not impact MTX efficacy in the CNS. CLINICAL TRIAL REGISTRATION: NCT03684980 (Registration date 26/09/2018).
Assuntos
Antineoplásicos , Neoplasias do Sistema Nervoso Central , Linfoma , Metotrexato , gama-Glutamil Hidrolase , Idoso , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Neoplasias do Sistema Nervoso Central/mortalidade , Feminino , Humanos , Linfoma/tratamento farmacológico , Linfoma/mortalidade , Masculino , Metotrexato/administração & dosagem , Metotrexato/efeitos adversos , Metotrexato/uso terapêutico , Pessoa de Meia-Idade , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/efeitos adversos , Proteínas Recombinantes/uso terapêutico , gama-Glutamil Hidrolase/administração & dosagem , gama-Glutamil Hidrolase/efeitos adversos , gama-Glutamil Hidrolase/uso terapêuticoRESUMO
Ibrutinib is a first-in-class inhibitor of Bruton tyrosine kinase (BTK) and has shown single-agent activity in recurrent/refractory central nervous system (CNS) lymphoma. Clinical responses are often transient or incomplete, suggesting a need for a combination therapy approach. We conducted a phase 1b clinical trial to explore the sequential combination of ibrutinib (560 or 840 mg daily dosing) with high-dose methotrexate (HD-MTX) and rituximab in patients with CNS lymphoma (CNSL). HD-MTX was given at 3.5 g/m2 every 2 weeks for a total of 8 doses (4 cycles; 1 cycle = 28 days). Ibrutinib was held on days of HD-MTX infusion and resumed 5 days after HD-MTX infusion or after HD-MTX clearance. Single-agent daily ibrutinib was administered continuously after completion of induction therapy until disease progression, intolerable toxicity, or death. We also explored next-generation sequencing of circulating tumor DNA (ctDNA) in cerebrospinal fluid (CSF) before and during treatment. The combination of ibrutinib, HD-MTX, and rituximab was tolerated with an acceptable safety profile (no grade 5 events, 3 grade 4 events). No dose-limiting toxicity was observed. Eleven of 15 patients proceeded to maintenance ibrutinib after completing 4 cycles of the ibrutinib/HD-MTX/rituximab combination. Clinical responses occurred in 12 of 15 patients (80%). Sustained tumor responses were associated with clearance of ctDNA from the CSF. This trial was registered at www.clinicaltrials.gov as #NCT02315326.
Assuntos
Antineoplásicos/uso terapêutico , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Linfoma/tratamento farmacológico , Metotrexato/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Rituximab/uso terapêutico , Adenina/análogos & derivados , Adulto , Tirosina Quinase da Agamaglobulinemia/antagonistas & inibidores , Idoso , Antineoplásicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Sistema Nervoso Central/genética , Neoplasias do Sistema Nervoso Central/patologia , DNA Tumoral Circulante/genética , Feminino , Humanos , Linfoma/genética , Linfoma/patologia , Metotrexato/efeitos adversos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologia , Piperidinas , Inibidores de Proteínas Quinases/efeitos adversos , Pirazóis/efeitos adversos , Pirazóis/farmacocinética , Pirimidinas/efeitos adversos , Pirimidinas/farmacocinética , Rituximab/efeitos adversos , Resultado do Tratamento , Adulto JovemRESUMO
PURPOSE: Current clinical and imaging tools remain suboptimal for predicting treatment response and prognosis in CNS lymphomas. We investigated the prognostic value of baseline [18F]FDG PET in patients with CNS lymphoma receiving ibrutinib-based treatments. METHODS: Fifty-three patients enrolled in a prospective clinical trial and underwent brain PET before receiving single-agent ibrutinib or ibrutinib in combination with methotrexate with or without rituximab. [18F]FDG uptake in these lesions was quantified by drawing PET volumes of interest around up to five [18F]FDG-avid lesions per patient (with uptake greater than surrounding brain). We measured standardized uptake values (SUVmax), metabolic tumor volumes, total lesion glycolysis (TLG), and the sum thereof in these lesions. We analyzed the relationship between PET parameters and mutation status, overall response rates, and progression-free survival (PFS). RESULTS: Thirty-eight patients underwent single-agent therapy and 15 received combination therapy. On PET, 15/53 patients had no measurable disease. In the other 38 patients, a total of 71 lesions were identified on PET. High-intensity [18F]FDG uptake and a larger volume of [18F]FDG-avid disease were inversely related to treatment outcome (p ≤ 0.005). In univariable analysis, PFS was linearly correlated with all PET parameters, with stronger association when sum-values were used. A multivariable model showed that risk of progression increased by 9% for every 5-unit increase in sumSUVmax (hazard ratio = 1.09 [95% CI: 1.04 to 1.14]). CONCLUSION: Higher lesional metabolic parameters are inversely related to outcome in patients undergoing ibrutinib-based therapies, and sumSUVmax emerged as a strong independent prognostic factor. TRIAL REGISTRATION: NCT02315326; https://clinicaltrials.gov/ct2/show/NCT02315326?term=NCT02315326&draw=2&rank=1.
Assuntos
Fluordesoxiglucose F18 , Linfoma não Hodgkin , Adenina/análogos & derivados , Glicólise , Humanos , Piperidinas , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Prognóstico , Estudos Prospectivos , Estudos Retrospectivos , Carga TumoralRESUMO
Background Mutant isocitrate dehydrogenase 1 and 2 (IDH1/IDH2) enzymes produce the oncometabolite D-2-hydroxyglutarate (2-HG). Ivosidenib (AG-120) is a targeted mutant IDH1 inhibitor under evaluation in a phase 1 dose escalation and expansion study of IDH1-mutant advanced solid tumors including cholangiocarcinoma, chondrosarcoma, and glioma. We explored the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of ivosidenib in these populations. Methods Ivosidenib was administered orally once (QD) or twice (BID) daily in continuous 28-day cycles; 168 patients received ≥1 dose within the range 100 mg BID to 1200 mg QD. PK and PD were assessed using validated liquid chromatography-tandem mass spectrometry assays. Results Ivosidenib demonstrated good oral exposure after single and multiple doses, was rapidly absorbed, and had a long terminal half-life (mean 40-102 h after single dose). Exposure increased less than dose proportionally. Steady state was reached by day 15, with moderate accumulation across all tumors (1.5- to 1.7-fold for area-under-the-curve at 500 mg QD). None of the intrinsic and extrinsic factors assessed affected ivosidenib exposure, including patient/disease characteristics and concomitant administration of weak CYP3A4 inhibitors/inducers. After multiple doses in patients with cholangiocarcinoma or chondrosarcoma, plasma 2-HG was reduced by up to 98%, to levels seen in healthy subjects. Exposure-response relationships for safety and efficacy outcomes were flat across the doses tested. Conclusions Ivosidenib demonstrated good oral exposure and a long half-life. Robust, persistent plasma 2-HG inhibition was observed in IDH1-mutant cholangiocarcinoma and chondrosarcoma. Ivosidenib 500 mg QD is an appropriate dose irrespective of various intrinsic and extrinsic factors. Trial RegistrationClinicalTrials.gov (NCT02073994).
Assuntos
Antineoplásicos/administração & dosagem , Antineoplásicos/farmacocinética , Glicina/análogos & derivados , Isocitrato Desidrogenase/antagonistas & inibidores , Neoplasias/metabolismo , Piridinas/administração & dosagem , Piridinas/farmacocinética , Administração Oral , Adulto , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/sangue , Relação Dose-Resposta a Droga , Feminino , Glutaratos/sangue , Glicina/administração & dosagem , Glicina/sangue , Glicina/farmacocinética , Humanos , Isocitrato Desidrogenase/genética , Masculino , Pessoa de Meia-Idade , Mutação , Neoplasias/sangue , Neoplasias/tratamento farmacológico , Piridinas/sangueRESUMO
Pediatric high-grade glioma (pHGG) is the leading cause of cancer death in children. Despite histologic similarities, it has recently become apparent that this disease is molecularly distinct from its adult counterpart. Specific hallmark oncogenic histone mutations within pediatric malignant gliomas divide these tumors into subgroups with different neuroanatomic and chronologic predilections. In this review, we will summarize the characteristic molecular alterations of pediatric high-grade gliomas, with a focus on how preclinical models of these alterations have furthered our understanding of their oncogenicity as well as their potential impact on developing targeted therapies for this devastating disease.
Assuntos
Neoplasias Encefálicas/genética , Carcinogênese/genética , Glioma/genética , Histonas/genética , Adulto , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Criança , Glioma/tratamento farmacológico , Glioma/patologia , Humanos , Mutação/genética , PediatriaRESUMO
PURPOSE: Perifosine (PRF) is an oral alkylphospholipid with antineoplastic effects and reasonable tolerability. It inhibits signaling through the PI3/AKT axis and other cascades of biologic importance in glioblastoma, and has promising pre-clinical activity in vitro and in vivo. Therefore, we conducted a phase II open-label single-arm clinical trial of perifosine for patients with recurrent glioblastoma (GBM). METHODS: We planned to accrue up to 30 adults with recurrent GBM with a minimum Karnofsky Performance Status of 50 following radiotherapy but without other restrictions on the number or types of prior therapy. Concurrent p450 stimulating hepatic enzyme inducing anticonvulsants were prohibited. Patients were treated with a loading dose of 600 mg PRF (in 4 divided doses on day 1) followed by 100 mg daily until either disease progression or intolerable toxicity. The primary endpoint was the 6-month progression free survival (PFS6) rate, with at least 20% considered promising. Accrual was continuous but if 0 of the first 12 patients with GBM reached PFS6, then further accrual would terminate for futility. Patients with other high grade gliomas were accrued concurrently to an exploratory cohort. RESULTS: Treatment was generally well tolerated; gastrointestinal toxicities were the most common side effects, although none resulted in treatment discontinuation. However, there was limited to no efficacy in GBM (n = 16): the PFS6 rate was 0%, median PFS was 1.58 months [95% CI (1.08, 1.84)], median overall survival was 3.68 months [95% CI (2.50, 7.79)], with no radiographic responses. There was a confirmed partial response in one patient with anaplastic astrocytoma (n = 14). CONCLUSIONS: PRF is tolerable but ineffective as monotherapy for GBM. Preclinical data suggests synergistic effects of PRF in combination with other approaches, and further study is ongoing.
Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Glioblastoma/tratamento farmacológico , Recidiva Local de Neoplasia/tratamento farmacológico , Fosforilcolina/análogos & derivados , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Adulto , Idoso , Neoplasias Encefálicas/patologia , Feminino , Seguimentos , Glioblastoma/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Fosforilcolina/uso terapêutico , Prognóstico , Estudos Prospectivos , Taxa de Sobrevida , Adulto JovemRESUMO
Purpose To assess the clinical safety, pharmacokinetics, and tumor imaging characteristics of fluorine 18-(2S,4R)-4-fluoroglutamine (FGln), a glutamine analog radiologic imaging agent. Materials and Methods This study was approved by the institutional review board and conducted under a U.S. Food and Drug Administration-approved Investigational New Drug application in accordance with the Helsinki Declaration and the Health Insurance Portability and Accountability Act. All patients provided written informed consent. Between January 2013 and October 2016, 25 adult patients with cancer received an intravenous bolus of FGln tracer (mean, 244 MBq ± 118, <100 µg) followed by positron emission tomography (PET) and blood radioassays. Patient data were summarized with descriptive statistics. FGln biodistribution and plasma amino acid levels in nonfasting patients (n = 13) were compared with those from patients who fasted at least 8 hours before injection (n = 12) by using nonparametric one-way analysis of variance with Bonferroni correction. Tumor FGln avidity versus fluorodeoxyglucose (FDG) avidity in patients with paired PET scans (n = 15) was evaluated with the Fisher exact test. P < .05 was considered indicative of a statistically significant difference. Results FGln PET depicted tumors of different cancer types (breast, pancreas, renal, neuroendocrine, lung, colon, lymphoma, bile duct, or glioma) in 17 of the 25 patients, predominantly clinically aggressive tumors with genetic mutations implicated in abnormal glutamine metabolism. Acute fasting had no significant effect on FGln biodistribution and plasma amino acid levels. FGln-avid tumors were uniformly FDG-avid but not vice versa (P = .07). Patients experienced no adverse effects. Conclusion Preliminary human FGln PET trial results provide clinical validation of abnormal glutamine metabolism as a potential tumor biomarker for targeted radiotracer imaging in several different cancer types. © RSNA, 2018 Online supplemental material is available for this article. Clinical trial registration no. NCT01697930.
Assuntos
Radioisótopos de Flúor/farmacocinética , Glutamina/análogos & derivados , Glutamina/metabolismo , Neoplasias/diagnóstico por imagem , Neoplasias/metabolismo , Tomografia por Emissão de Pósitrons , Adulto , Idoso , Biomarcadores Tumorais/metabolismo , Transformação Celular Neoplásica , Feminino , Radioisótopos de Flúor/metabolismo , Glutamina/farmacocinética , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/patologia , Distribuição Tecidual/efeitos dos fármacos , Estados Unidos , United States Food and Drug AdministrationRESUMO
Copy number alteration (CNA) profiling of human tumors has revealed recurrent patterns of DNA amplifications and deletions across diverse cancer types. These patterns are suggestive of conserved selection pressures during tumor evolution but cannot be fully explained by known oncogenes and tumor suppressor genes. Using a pan-cancer analysis of CNA data from patient tumors and experimental systems, here we show that principal component analysis-defined CNA signatures are predictive of glycolytic phenotypes, including 18F-fluorodeoxy-glucose (FDG) avidity of patient tumors, and increased proliferation. The primary CNA signature is enriched for p53 mutations and is associated with glycolysis through coordinate amplification of glycolytic genes and other cancer-linked metabolic enzymes. A pan-cancer and cross-species comparison of CNAs highlighted 26 consistently altered DNA regions, containing 11 enzymes in the glycolysis pathway in addition to known cancer-driving genes. Furthermore, exogenous expression of hexokinase and enolase enzymes in an experimental immortalization system altered the subsequent copy number status of the corresponding endogenous loci, supporting the hypothesis that these metabolic genes act as drivers within the conserved CNA amplification regions. Taken together, these results demonstrate that metabolic stress acts as a selective pressure underlying the recurrent CNAs observed in human tumors, and further cast genomic instability as an enabling event in tumorigenesis and metabolic evolution.
Assuntos
Variações do Número de Cópias de DNA , Perfilação da Expressão Gênica/métodos , Glicólise , Neoplasias/genética , Linhagem Celular Tumoral , Evolução Molecular , Amplificação de Genes , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Instabilidade Genômica , Humanos , Redes e Vias Metabólicas , Análise de Componente Principal , Seleção GenéticaRESUMO
Both genome-wide genetic and epigenetic alterations are fundamentally important for the development of cancers, but the interdependence of these aberrations is poorly understood. Glioblastomas and other cancers with the CpG island methylator phenotype (CIMP) constitute a subset of tumours with extensive epigenomic aberrations and a distinct biology. Glioma CIMP (G-CIMP) is a powerful determinant of tumour pathogenicity, but the molecular basis of G-CIMP remains unresolved. Here we show that mutation of a single gene, isocitrate dehydrogenase 1 (IDH1), establishes G-CIMP by remodelling the methylome. This remodelling results in reorganization of the methylome and transcriptome. Examination of the epigenome of a large set of intermediate-grade gliomas demonstrates a distinct G-CIMP phenotype that is highly dependent on the presence of IDH mutation. Introduction of mutant IDH1 into primary human astrocytes alters specific histone marks, induces extensive DNA hypermethylation, and reshapes the methylome in a fashion that mirrors the changes observed in G-CIMP-positive lower-grade gliomas. Furthermore, the epigenomic alterations resulting from mutant IDH1 activate key gene expression programs, characterize G-CIMP-positive proneural glioblastomas but not other glioblastomas, and are predictive of improved survival. Our findings demonstrate that IDH mutation is the molecular basis of CIMP in gliomas, provide a framework for understanding oncogenesis in these gliomas, and highlight the interplay between genomic and epigenomic changes in human cancers.
Assuntos
Metilação de DNA/genética , Glioma/genética , Isocitrato Desidrogenase/genética , Mutação/genética , Fenótipo , Astrócitos/citologia , Astrócitos/metabolismo , Sobrevivência Celular/genética , Células Cultivadas , Ilhas de CpG/genética , Epigênese Genética , Epigenômica , Regulação da Expressão Gênica , Glioblastoma/genética , Glioblastoma/patologia , Glioma/patologia , Células HEK293 , Histonas/metabolismo , Humanos , Isocitrato Desidrogenase/metabolismo , Metaboloma/genética , Células Tumorais CultivadasRESUMO
Recurrent mutations in isocitrate dehydrogenase 1 (IDH1) and IDH2 have been identified in gliomas, acute myeloid leukaemias (AML) and chondrosarcomas, and share a novel enzymatic property of producing 2-hydroxyglutarate (2HG) from α-ketoglutarate. Here we report that 2HG-producing IDH mutants can prevent the histone demethylation that is required for lineage-specific progenitor cells to differentiate into terminally differentiated cells. In tumour samples from glioma patients, IDH mutations were associated with a distinct gene expression profile enriched for genes expressed in neural progenitor cells, and this was associated with increased histone methylation. To test whether the ability of IDH mutants to promote histone methylation contributes to a block in cell differentiation in non-transformed cells, we tested the effect of neomorphic IDH mutants on adipocyte differentiation in vitro. Introduction of either mutant IDH or cell-permeable 2HG was associated with repression of the inducible expression of lineage-specific differentiation genes and a block to differentiation. This correlated with a significant increase in repressive histone methylation marks without observable changes in promoter DNA methylation. Gliomas were found to have elevated levels of similar histone repressive marks. Stable transfection of a 2HG-producing mutant IDH into immortalized astrocytes resulted in progressive accumulation of histone methylation. Of the marks examined, increased H3K9 methylation reproducibly preceded a rise in DNA methylation as cells were passaged in culture. Furthermore, we found that the 2HG-inhibitable H3K9 demethylase KDM4C was induced during adipocyte differentiation, and that RNA-interference suppression of KDM4C was sufficient to block differentiation. Together these data demonstrate that 2HG can inhibit histone demethylation and that inhibition of histone demethylation can be sufficient to block the differentiation of non-transformed cells.
Assuntos
Diferenciação Celular/genética , Histonas/metabolismo , Isocitrato Desidrogenase/genética , Mutação/genética , Células 3T3-L1 , Adipócitos/citologia , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Astrócitos/citologia , Astrócitos/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Linhagem da Célula/genética , Metilação de DNA/efeitos dos fármacos , Indução Enzimática/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Glioma/enzimologia , Glioma/genética , Glioma/patologia , Glutaratos/metabolismo , Glutaratos/farmacologia , Células HEK293 , Humanos , Isocitrato Desidrogenase/antagonistas & inibidores , Isocitrato Desidrogenase/metabolismo , Histona Desmetilases com o Domínio Jumonji/antagonistas & inibidores , Histona Desmetilases com o Domínio Jumonji/deficiência , Histona Desmetilases com o Domínio Jumonji/genética , Histona Desmetilases com o Domínio Jumonji/metabolismo , Metilação/efeitos dos fármacos , Camundongos , Células-Tronco Neurais/metabolismo , Regiões Promotoras Genéticas/genéticaRESUMO
IQGAP1 is a scaffolding protein previously implicated in adherens junction formation. However, its role in the establishment or maintenance of tight junctions (TJs) has not been explored. We hypothesized that IQGAP1 could regulate TJ formation by modulating the expression and/or localization of junctional proteins, and we systematically tested this hypothesis in the model Madin-Darby canine kidney (MDCK) cell line. We find that IQGAP1 silencing enhances a transient increase in transepithelial electrical resistance (TER) observed during the early stages of TJ formation (Cereijido et al., 1978). Quantitative microscopy and biochemical experiments suggest that this effect of IQGAP1 on TJ assembly is accounted for by reduced expression and TJ recruitment of claudin 2, and increased TJ recruitment of claudin 4. Furthermore, we show that IQGAP1 also regulates TJ formation through its interactor CDC42, because IQGAP1 knockdown increases the activity of the CDC42 effector JNK and dominant-negative CDC42 prevents the increase in TER caused by IQGAP1 silencing. Hence, we provide evidence that IQGAP1 modulates TJ formation by a twofold mechanism: (1) controlling the expression and recruitment of claudin 2 and recruitment of claudin 4 to the TJ, and (2) transient inhibition of the CDC42-JNK pathway.
Assuntos
Claudina-2/metabolismo , Claudina-4/metabolismo , Junções Íntimas/metabolismo , Proteínas Ativadoras de ras GTPase/metabolismo , Animais , Claudina-2/genética , Claudina-4/genética , Cães , MAP Quinase Quinase 4/genética , MAP Quinase Quinase 4/metabolismo , Células Madin Darby de Rim Canino , Junções Íntimas/genética , Proteína cdc42 de Ligação ao GTP/genética , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteínas Ativadoras de ras GTPase/genéticaRESUMO
Epidermal growth factor receptor (EGFR) mutations are commonly observed in Glioblastoma (GBM) and have long posed as a target for new therapies. Trials involving erlotinib have shown mixed results, likely owing to a mechanism of the mutation that may instead favor other EGFR inhibitors, such as lapatinib. We aimed to determine whether or not pulse high-dose lapatinib was a safe and tolerable regimen in addition to standard therapy. We recruited adult patients with newly-diagnosed GBM who had Karnofsky Performance Status ≥60, normal baseline hematological, hepatic, and renal function tests, and no prior history of radiation or treatment with EGFR inhibitor. Lapatinib was administered at 2500 mg twice daily for two consecutive days per week on a weekly basis throughout concomitant and adjuvant standard therapy. The primary endpoints were tolerability and safety. 12 patients were enrolled in this study over 2 years. Of the non-hematological adverse events, there were 2 grade 3 events, fatigue and post-radiation cystic brain necrosis. The most common adverse events in general were fatigue, rashes, and diarrhea. Of the hematological adverse events, there were 13 grade 3 events, all of which were due to lymphopenia and affected 6 of 12 patients. Pulse high-dose lapatinib in addition to standard therapy for newly-diagnosed GBM is a tolerable and safe regimen, but higher rates of lymphopenia should be noted. However, further investigations will be required to evaluate the efficacy of this combination for the treatments of GBM. Trial registration ClinicalTrials.gov Identifier: NCT01591577.
Assuntos
Antineoplásicos/administração & dosagem , Neoplasias Encefálicas/terapia , Quimiorradioterapia , Dacarbazina/análogos & derivados , Glioblastoma/terapia , Quinazolinas/administração & dosagem , Adulto , Idoso , Antineoplásicos/efeitos adversos , Quimiorradioterapia/efeitos adversos , Quimiorradioterapia/métodos , Dacarbazina/administração & dosagem , Dacarbazina/efeitos adversos , Esquema de Medicação , Feminino , Humanos , Avaliação de Estado de Karnofsky , Lapatinib , Masculino , Pessoa de Meia-Idade , Necrose/etiologia , Projetos Piloto , Quinazolinas/efeitos adversos , Temozolomida , Trombocitopenia/etiologia , Resultado do TratamentoRESUMO
Systematic efforts are underway to decipher the genetic changes associated with tumor initiation and progression. However, widespread clinical application of this information is hampered by an inability to identify critical genetic events across the spectrum of human tumors with adequate sensitivity and scalability. Here, we have adapted high-throughput genotyping to query 238 known oncogene mutations across 1,000 human tumor samples. This approach established robust mutation distributions spanning 17 cancer types. Of 17 oncogenes analyzed, we found 14 to be mutated at least once, and 298 (30%) samples carried at least one mutation. Moreover, we identified previously unrecognized oncogene mutations in several tumor types and observed an unexpectedly high number of co-occurring mutations. These results offer a new dimension in tumor genetics, where mutations involving multiple cancer genes may be interrogated simultaneously and in 'real time' to guide cancer classification and rational therapeutic intervention.
Assuntos
Análise Mutacional de DNA/métodos , Mutação , Neoplasias/genética , Oncogenes , Perfilação da Expressão Gênica , Genoma Humano , Genótipo , HumanosRESUMO
The physicochemical design and synthesis of effective cancer-directed and particle-based nanotherapeutic imaging agents remains a challenging task. Of critical importance is the ability to demonstrate maximum delivery, retention, and treatment efficacy for platforms designed to deposit their cargo at sites of disease without attendant dose-limiting toxicity. In this work, we describe dual-modality nanoparticle drug conjugates (NDCs) which utilize protease sensitive linkers to attached drug compounds and imaging labels to a clinically translated class of ultrasmall silica nanoparticle (C' dots). We describe the synthesis and characterization of these linker-drug constructs. Linkers incorporating dipeptide enzyme substrates are attached to analogs of a prototypical epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), through a cleavable amide bond or para-aminobenzyloxycarbonyl (PABC) group. These constructs are conjugated onto C' dots leading to the desired NDCs. These NDCs exhibit fast and predictable release kinetics in the presence of model proteases, and are stable in various biological media. Finally, in vitro assays show NDCs to be highly active in reducing phosphorylated EGFR levels in H1650 cells, a human tumor-derived cell line. The data suggests that NDCs exhibit desirable properties that warrant further development toward oncological therapy.