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1.
Neuro Oncol ; 26(2): 348-361, 2024 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-37715730

RESUMEN

BACKGROUND: Recurrent brain tumors are the leading cause of cancer death in children. Indoleamine 2,3-dioxygenase (IDO) is a targetable metabolic checkpoint that, in preclinical models, inhibits anti-tumor immunity following chemotherapy. METHODS: We conducted a phase I trial (NCT02502708) of the oral IDO-pathway inhibitor indoximod in children with recurrent brain tumors or newly diagnosed diffuse intrinsic pontine glioma (DIPG). Separate dose-finding arms were performed for indoximod in combination with oral temozolomide (200 mg/m2/day x 5 days in 28-day cycles), or with palliative conformal radiation. Blood samples were collected at baseline and monthly for single-cell RNA-sequencing with paired single-cell T cell receptor sequencing. RESULTS: Eighty-one patients were treated with indoximod-based combination therapy. Median follow-up was 52 months (range 39-77 months). Maximum tolerated dose was not reached, and the pediatric dose of indoximod was determined as 19.2 mg/kg/dose, twice daily. Median overall survival was 13.3 months (n = 68, range 0.2-62.7) for all patients with recurrent disease and 14.4 months (n = 13, range 4.7-29.7) for DIPG. The subset of n = 26 patients who showed evidence of objective response (even a partial or mixed response) had over 3-fold longer median OS (25.2 months, range 5.4-61.9, p = 0.006) compared to n = 37 nonresponders (7.3 months, range 0.2-62.7). Four patients remain free of active disease longer than 36 months. Single-cell sequencing confirmed emergence of new circulating CD8 T cell clonotypes with late effector phenotype. CONCLUSIONS: Indoximod was well tolerated and could be safely combined with chemotherapy and radiation. Encouraging preliminary evidence of efficacy supports advancing to Phase II/III trials for pediatric brain tumors.


Asunto(s)
Neoplasias Encefálicas , Neoplasias del Tronco Encefálico , Humanos , Niño , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/patología , Temozolomida , Triptófano , Factores Inmunológicos , Inmunoterapia , Neoplasias del Tronco Encefálico/patología
2.
Clin Cancer Res ; 29(24): 5031-5037, 2023 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-37498309

RESUMEN

PURPOSE: Treatment of wingless (WNT)-activated medulloblastoma (WNT+MB) with surgery, irradiation (XRT), and chemotherapy results in excellent outcomes. We studied the efficacy of therapy de-intensification by omitting XRT entirely in children with WNT+MB. PATIENTS AND METHODS: Tumors were molecularly screened to confirm the diagnosis of WNT+MB. Eligible children were treated within 31 days following surgery with nine cycles of adjuvant chemotherapy per ACNS0331. No XRT was planned. The primary endpoint was the occurrence of relapse, progression, or death in the absence of XRT within the first two years after study enrollment. Four events in the first 10 evaluable patients would result in early study closure. RESULTS: Fourteen children were prescreened, and nine met the protocol definition of WNT+MB. Six of the nine eligible patients consented to protocol therapy, and five completed planned protocol therapy. The first two children enrolled relapsed shortly after therapy completion with local and leptomeningeal recurrences. The study was closed early due to safety concerns. Both children are surviving after XRT and additional chemotherapy. A third child relapsed at completion of therapy but died of progressive disease 35 months from diagnosis. Two children finished treatment but immediately received post-treatment XRT to guard against early relapse. The final child's treatment was aborted in favor of a high-dose therapy/stem cell rescue approach. Although OS at 5 years is 83%, no child received only planned protocol therapy, with all receiving eventual XRT and/or alternative therapy. CONCLUSIONS: Radiotherapy is required to effectively treat children with WNT-altered medulloblastoma. See related commentary by Gottardo and Gajjar, p. 4996.


Asunto(s)
Neoplasias Cerebelosas , Meduloblastoma , Niño , Humanos , Meduloblastoma/tratamiento farmacológico , Meduloblastoma/radioterapia , Terapia Combinada , Proyectos Piloto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Recurrencia Local de Neoplasia/tratamiento farmacológico , Neoplasias Cerebelosas/tratamiento farmacológico , Neoplasias Cerebelosas/radioterapia , Recurrencia
3.
Genome Biol ; 22(1): 125, 2021 04 29.
Artículo en Inglés | MEDLINE | ID: mdl-33926529

RESUMEN

BACKGROUND: Medulloblastoma (MB) is the most common malignant pediatric brain tumor that originates in the cerebellum and brainstem. Frequent somatic mutations and deregulated expression of epigenetic regulators in MB highlight the substantial role of epigenetic alterations. 5-hydroxymethylcytosine (5hmC) is a highly abundant cytosine modification in the developing cerebellum and is regulated by ten-eleven translocation (TET) enzymes. RESULTS: We investigate the alterations of 5hmC and TET enzymes in MB and their significance to cerebellar cancer formation. We show total abundance of 5hmC is reduced in MB, but identify significant enrichment of MB-specific 5hmC marks at regulatory regions of genes implicated in stem-like properties and Nanog-binding motifs. While TET1 and TET2 levels are high in MBs, only knockout of Tet1 in the smoothened (SmoA1) mouse model attenuates uncontrolled proliferation, leading to a favorable prognosis. The pharmacological Tet1 inhibition reduces cell viability and platelet-derived growth factor signaling pathway-associated genes. CONCLUSIONS: These results together suggest a potential key role of 5hmC and indicate an oncogenic nature for TET1 in MB tumorigenesis, suggesting it as a potential therapeutic target for MBs.


Asunto(s)
Susceptibilidad a Enfermedades , Meduloblastoma/etiología , Meduloblastoma/metabolismo , Oxigenasas de Función Mixta/genética , Oxigenasas de Función Mixta/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , 5-Metilcitosina/análogos & derivados , Animales , Biomarcadores de Tumor , Biología Computacional/métodos , Islas de CpG , Metilación de ADN , Bases de Datos de Ácidos Nucleicos , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Epigénesis Genética , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Meduloblastoma/mortalidad , Meduloblastoma/patología , Ratones , Ratones Transgénicos , Motivos de Nucleótidos , Pronóstico
4.
Oncotarget ; 11(44): 4074-4075, 2020 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-33216843

RESUMEN

[This corrects the article DOI: 10.18632/oncotarget.21765.].

5.
Dev Cell ; 48(2): 129-130, 2019 01 28.
Artículo en Inglés | MEDLINE | ID: mdl-30695693

RESUMEN

In the developing cerebellum, Sonic hedgehog (SHH) signaling is required for expansion of cerebellar granule neural progenitors, proposed to be cells-of-origin for the SHH-driven pediatric brain tumor medulloblastoma. In this issue of Developmental Cell, Chang et al. (2019) show that the transcription factor Atoh1/MATH1 regulates primary cilium formation, enabling SHH signaling.


Asunto(s)
Neoplasias Cerebelosas , Meduloblastoma , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Proliferación Celular , Cerebelo , Niño , Cilios , Proteínas Hedgehog , Humanos , Neuronas
6.
Oncotarget ; 8(55): 94393-94406, 2017 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-29212236

RESUMEN

Expression of the inflammatory cytokine growth differentiation factor 15 (GDF15) is significantly elevated in many tumor types in association with epithelial mesenchymal transition (EMT), drug resistance, and progressive disease. However, few studies have examined GDF15 expression, signaling, or function in breast cancer. In the current study, we demonstrate that GDF15 is associated with high tumor grade, ER-negativity, and HER2 overexpression in patients with breast cancer. Stable overexpression of GDF15 upregulates expression of mesenchymal markers and transcription factors, including FoxM1, and increases cellular invasion. GDF15 stable clones and breast cancer cells stimulated with recombinant human GDF15 (rhGDF15) demonstrate activation of insulin-like growth factor-1 receptor (IGF-1R), EMT, and invasion. Pharmacologic inhibition of IGF-1R reduces GDF15-mediated EMT and invasion in stable clones, and FoxM1 knockdown rescues invasion and EMT in GDF15 stable clones and rhGDF15-stimulated cells. These data suggest that IGF-1R-FoxM1 signaling is a potential mechanism through which GDF15 drives EMT and invasion of breast cancers. Further, GDF15 knockdown significantly inhibits invasion of HER2-overexpressing and triple-negative breast cancer cells, supporting further preclinical investigation of GDF15-targeted therapies.

7.
Oncoscience ; 3(7-8): 186-187, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27713908
8.
Carcinogenesis ; 36 Suppl 1: S2-18, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26106139

RESUMEN

As part of the Halifax Project, this review brings attention to the potential effects of environmental chemicals on important molecular and cellular regulators of the cancer hallmark of evading growth suppression. Specifically, we review the mechanisms by which cancer cells escape the growth-inhibitory signals of p53, retinoblastoma protein, transforming growth factor-beta, gap junctions and contact inhibition. We discuss the effects of selected environmental chemicals on these mechanisms of growth inhibition and cross-reference the effects of these chemicals in other classical cancer hallmarks.


Asunto(s)
Exposición a Riesgos Ambientales/efectos adversos , Sustancias Peligrosas/efectos adversos , Neoplasias/inducido químicamente , Neoplasias/etiología , Animales , Humanos , Transducción de Señal/efectos de los fármacos
9.
Mol Pharmacol ; 87(2): 150-61, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25391374

RESUMEN

Resistance to the human epidermal growth factor receptor (HER2)-targeted antibody trastuzumab is a major clinical concern in the treatment of HER2-positive metastatic breast cancer. Increased expression or signaling from the insulin-like growth factor-1 receptor (IGF-1R) has been reported to be associated with trastuzumab resistance. However, the specific molecular and biologic mechanisms through which IGF-1R promotes resistance or disease progression remain poorly defined. In this study, we found that the major biologic effect promoted by IGF-1R was invasion, which was mediated by both Src-focal adhesion kinase (FAK) signaling and Forkhead box protein M1 (FoxM1). Cotargeting IGF-1R and HER2 using either IGF-1R antibodies or IGF-1R short hairpin RNA in combination with trastuzumab resulted in significant but modest growth inhibition. Reduced invasion was the most significant biologic effect achieved by cotargeting IGF-1R and HER2 in trastuzumab-resistant cells. Constitutively active Src blocked the anti-invasive effect of IGF-1R/HER2 cotargeted therapy. Furthermore, knockdown of FoxM1 blocked IGF-1-mediated invasion, and dual targeting of IGF-1R and HER2 reduced expression of FoxM1. Re-expression of FoxM1 restored the invasive potential of IGF-1R knockdown cells treated with trastuzumab. Overall, our results strongly indicate that therapeutic combinations that cotarget IGF-1R and HER2 may reduce the invasive potential of cancer cells that are resistant to trastuzumab through mechanisms that depend in part on Src and FoxM1.


Asunto(s)
Neoplasias de la Mama/metabolismo , Quinasa 1 de Adhesión Focal/biosíntesis , Factores de Transcripción Forkhead/biosíntesis , Regulación Neoplásica de la Expresión Génica , Receptor ErbB-2/biosíntesis , Receptor IGF Tipo 1/biosíntesis , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Línea Celular Tumoral , Femenino , Proteína Forkhead Box M1 , Genes src/fisiología , Humanos , ARN Interferente Pequeño/administración & dosificación , ARN Interferente Pequeño/genética , Receptor ErbB-2/antagonistas & inhibidores , Receptor ErbB-2/genética , Receptor IGF Tipo 1/antagonistas & inhibidores , Receptor IGF Tipo 1/genética , Transducción de Señal/fisiología
10.
Neuro Oncol ; 16(1): 9-20, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24305711

RESUMEN

Medulloblastoma (MB) is the most frequent malignant brain tumor in children. Patients with MB who are classified as having high-risk disease or those with recurrent disease respond poorly to current therapies and have an increased risk of MB-related mortality. Preclinical studies and molecular profiling of MB tumors have revealed upregulation or activation of several key signaling pathways such as the sonic hedgehog and WNT pathways. Although the exact mechanisms underlying MB tumorigenesis remain poorly understood, inhibiting these key pathways with molecularly targeted therapies represents an important approach to improving MB outcomes. Several molecularly targeted therapies are already under clinical investigation in MB patients. We discuss current preclinical and clinical data, as well as data from clinical trials of targeted therapies that are either ongoing or in development for MB.


Asunto(s)
Antineoplásicos/uso terapéutico , Neoplasias Cerebelosas/tratamiento farmacológico , Meduloblastoma/tratamiento farmacológico , Terapia Molecular Dirigida , Proteínas de Neoplasias/antagonistas & inhibidores , Animales , Neoplasias Cerebelosas/metabolismo , Humanos , Meduloblastoma/metabolismo , Transducción de Señal
11.
J Pediatr Hematol Oncol ; 36(7): e448-51, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24276039

RESUMEN

BACKGROUND: Brain subependymal giant cell astrocytomas (SEGAs) in patients with tuberous sclerosis have been reported to respond to everolimus. METHODS: A 15-year-old male patient with intractable seizures and multiple SEGAs of the brain developed leptomeningeal enhancement and multiple metastatic, histologically confirmed SEGAs of the spinal cord. He received daily everolimus at a dose of 3 mg/m for 6 weeks, which was then increased to 6 mg/m. RESULTS: Magnetic resonance image of the brain and spine showed significant reduction in the size of SEGAs after 6 weeks of treatment. The patient has remained free of progression for 24 months. Additional benefits included: excellent seizure control, decrease in the size of cardiac rhabdomyomas, and improved quality of life. CONCLUSIONS: We describe a rare case of metastatic SEGA, which was successfully treated with everolimus.


Asunto(s)
Astrocitoma/tratamiento farmacológico , Neoplasias Encefálicas/tratamiento farmacológico , Sirolimus/análogos & derivados , Neoplasias de la Médula Espinal/tratamiento farmacológico , Adolescente , Antineoplásicos/uso terapéutico , Astrocitoma/patología , Neoplasias Encefálicas/patología , Everolimus , Humanos , Masculino , Sirolimus/uso terapéutico , Neoplasias de la Médula Espinal/secundario , Resultado del Tratamiento , Esclerosis Tuberosa/tratamiento farmacológico , Esclerosis Tuberosa/patología
12.
Childs Nerv Syst ; 29(4): 589-96, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23296323

RESUMEN

PURPOSE: Chemotherapy for relapsed medulloblastoma has been inadequate, and most patients succumb to disease. METHODS: We retrospectively reviewed nine cases of relapsed medulloblastoma treated with bevacizumab, irinotecan, ± temozolomide. Patients received one to three prior therapeutic regimens. Five patients received 10 mg/kg bevacizumab and 125-150 mg/m(2) irinotecan IV every 2 weeks, with temozolomide, starting at a median dose of 150 mg/m(2) orally for 5 days monthly. Two patients received bevacizumab and irinotecan, but not temozolomide, due to provider preference. Two of nine patients received 15 mg/kg bevacizumab IV, 90 mg/m(2) irinotecan orally for five consecutive days, 100 mg/m(2)/day temozolomide IV for 5 days, and 1.5 mg/m(2) vincristine IV, each administered every 21 days. RESULTS: Median time to progression was 11 months. Median overall survival was 13 months. Objective tumor response at 3 months was 67 %, including six patients with partial response (PR) and three patients with stable disease (SD). At 6 months, objective response was 55 %, with two patients with PR and three with complete response. Additionally, one patient had SD and three had PD. Two patients remain alive and progression free at 15 and 55 months; another is alive with disease at 20 months. Toxicities included two patients with grade III neutropenia, two with grade III thrombocytopenia, one with grade III elevation of liver function tests, and one patient with grade III diarrhea. CONCLUSIONS: The combination of bevacizumab and irinotecan, with or without temozolomide, produces objective responses with minimal toxicity in children with recurrent medulloblastoma. Prospective clinical trials are needed to evaluate the efficacy of this strategy.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Encefálicas/tratamiento farmacológico , Meduloblastoma/tratamiento farmacológico , Adolescente , Anticuerpos Monoclonales Humanizados/administración & dosificación , Anticuerpos Monoclonales Humanizados/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Bevacizumab , Camptotecina/administración & dosificación , Camptotecina/análogos & derivados , Camptotecina/uso terapéutico , Niño , Preescolar , Dacarbazina/administración & dosificación , Dacarbazina/análogos & derivados , Dacarbazina/uso terapéutico , Esquema de Medicación , Femenino , Humanos , Lactante , Irinotecán , Masculino , Recurrencia , Estudios Retrospectivos , Temozolomida , Resultado del Tratamiento
13.
Neuro Oncol ; 14(4): 440-58, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22379189

RESUMEN

Medulloblastoma is the most common malignant childhood brain tumor. The protein phosphatase and oncogene WIP1 is over-expressed or amplified in a significant number of primary human medulloblastomas and cell lines. In the present study, we examine an important mechanism by which WIP1 promotes medulloblastoma growth using in vitro and in vivo models. Human cell lines and intracerebellar xenografted animal models were used to study the role of WIP1 and the major TP53 regulator, HDM2, in medulloblastoma growth. Stable expression of WIP1 enhances growth of TP53 wild-type medulloblastoma cells, compared with cells with stable expression of an empty-vector or mutant WIP1. In an animal model, WIP1 enhances proliferation and reduces the survival of immunodeficient mice bearing intracerebellar xenografted human medulloblastoma cells. Cells with increased WIP1 expression also exhibit increased expression of HDM2. HDM2 knockdown or treatment with the HDM2 inhibitor Nutlin-3a, the active enantomer of Nutlin-3, specifically inhibits the growth of medulloblastoma cells with increased WIP1 expression. Nutlin-3a does not affect growth of medulloblastoma cells with stable expression of an empty vector or of mutant WIP1. Knockdown of WIP1 or treatment with the WIP1 inhibitor CCT007093 results in increased phosphorylation of known WIP1 targets, reduced HDM2 expression, and reduced growth specifically in WIP1 wild-type and high-expressing medulloblastoma cells. Combined WIP1 and HDM2 inhibition is more effective than WIP1 inhibition alone in blocking growth of WIP1 high-expressing medulloblastoma cells. Our preclinical study supports a role for therapies that target WIP1 and HDM2 in the treatment of medulloblastoma.


Asunto(s)
Neoplasias Cerebelosas/genética , Meduloblastoma/metabolismo , Fosfoproteínas Fosfatasas/metabolismo , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Animales , Línea Celular Tumoral , Proliferación Celular , Supervivencia Celular , Neoplasias Cerebelosas/metabolismo , Regulación Neoplásica de la Expresión Génica , Humanos , Meduloblastoma/genética , Ratones , Fosfoproteínas Fosfatasas/genética , Proteína Fosfatasa 2C , Proteínas Proto-Oncogénicas c-mdm2/genética , Trasplante Heterólogo , Proteína p53 Supresora de Tumor/genética
14.
J Neurooncol ; 101(2): 215-26, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20524040

RESUMEN

We previously showed that inhibition of the platelet-derived growth factor receptor (PDGFR) blocks the survival and migration of medulloblastoma cells. Identification of in vitro PDGFR-targeting pharmacologic agents that are suitable for preclinical testing in medulloblastoma models in vivo will be critical for efficiently translating these agents to clinical investigation in children with medulloblastoma. In this study, we investigated whether the multi-tyrosine kinase inhibitor sunitinib, effectively inhibits PDGFR signaling required for medulloblastoma cell migration. Daoy and D556 human medulloblastoma cells pre-treated for 1 h with 0.2 µM sunitinib demonstrated induction of PTEN expression and significant inhibition of PDGFR signaling activity and transactivation of EGFR, in a RAS-independent manner, in response to PDGF-BB stimulation. Sunitinib pre-treatment markedly reduced medulloblastoma cell migration in response to both PDGF-BB and 10% serum at 4 and 24 h after treatment. Pre-treatment with sunitinib for 1 h also resulted in detachment and decreased viability of D556, but not Daoy, cells and only after 48 h following treatment. However, sunitinib did not induce apoptosis in either cell line at any time point, indicating that the anti-migratory effects of sunitinib were not due to impeding cell survival. Sunitinib similarly inhibited PDGFR signaling and migration of primary murine Smo/Smo medulloblastoma cells, suggesting that the Smo/Smo mouse is an appropriate model for preclinical testing of sunitinib. These results indicate that sunitinib may be an important pharmacologic agent for the treatment of invasive medulloblastoma, particularly given evidence of its ability to cross the blood-brain barrier to target tumor cells, and thus warrants further in vivo testing for confirmation of efficacy.


Asunto(s)
Antineoplásicos/farmacología , Movimiento Celular/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Indoles/farmacología , Fosfohidrolasa PTEN/metabolismo , Pirroles/farmacología , Receptores del Factor de Crecimiento Derivado de Plaquetas/metabolismo , Transducción de Señal/efectos de los fármacos , Inductores de la Angiogénesis/farmacología , Animales , Becaplermina , Recuento de Células/métodos , Línea Celular Tumoral , Células Cultivadas , Relación Dosis-Respuesta a Droga , Factor de Crecimiento Epidérmico/farmacología , Humanos , Meduloblastoma/patología , Ratones , Fosfohidrolasa PTEN/genética , Factor de Crecimiento Derivado de Plaquetas/farmacología , Proteínas Proto-Oncogénicas c-sis , Receptores del Factor de Crecimiento Derivado de Plaquetas/genética , Sunitinib , Factores de Tiempo
15.
PLoS One ; 5(5): e10849, 2010 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-20520772

RESUMEN

BACKGROUND: Recent publications have described an important role for cross talk between PI-3 kinase and sonic hedgehog signaling pathways in the pathogenesis of medulloblastoma. METHODOLOGY/PRINCIPAL FINDINGS: We crossed mice with constitutive activation of Smoothened, SmoA1, with Pten deficient mice. Both constitutive and conditional Pten deficiency doubled the incidence of mice with symptoms of medulloblastoma and resulted in decreased survival. Analysis revealed a clear separation of gene signatures, with up-regulation of genes in the PI-3 kinase signaling pathway, including downstream activation of angiogenesis in SmoA1+/-; Pten +/- medulloblastomas. Western blotting and immunohistochemistry confirmed reduced or absent Pten, Akt activation, and increased angiogenesis in Pten deficient tumors. Down-regulated genes included genes in the sonic hedgehog pathway and tumor suppressor genes. SmoA1+/-; Pten +/+ medulloblastomas appeared classic in histology with increased proliferation and diffuse staining for apoptosis. In contrast, Pten deficient tumors exhibited extensive nodularity with neuronal differentiation separated by focal areas of intense staining for proliferation and virtually absent apoptosis. Examination of human medulloblastomas revealed low to absent PTEN expression in over half of the tumors. Kaplan-Meier analysis confirmed worse overall survival in patients whose tumor exhibited low to absent PTEN expression. CONCLUSIONS/SIGNIFICANCE: This suggests that PTEN expression is a marker of favorable prognosis and mouse models with activation of PI-3 kinase pathways may be important tools for preclinical evaluation of promising agents for the treatment of medulloblastoma.


Asunto(s)
Heterocigoto , Meduloblastoma/enzimología , Meduloblastoma/patología , Fosfohidrolasa PTEN/genética , Alelos , Animales , Apoptosis , Diferenciación Celular , Proliferación Celular , Modelos Animales de Enfermedad , Regulación hacia Abajo , Proteínas Hedgehog/metabolismo , Humanos , Meduloblastoma/irrigación sanguínea , Meduloblastoma/diagnóstico , Ratones , Neovascularización Patológica/enzimología , Neuronas/enzimología , Neuronas/patología , Fosfatidilinositol 3-Quinasas/metabolismo , Pronóstico , Transducción de Señal , Análisis de Supervivencia , Regulación hacia Arriba
16.
J Neurooncol ; 86(3): 245-56, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17932621

RESUMEN

Medulloblastoma is the most common malignant brain tumor of childhood. Despite numerous advances, clinical challenges range from recurrent and progressive disease to long-term toxicities in survivors. The lack of more effective, less toxic therapies results from our limited understanding of medulloblastoma growth. Although TP53 is the most commonly altered gene in cancers, it is rarely mutated in medulloblastoma. Accumulating evidence, however, indicates that TP53 pathways are disrupted in medulloblastoma. Wild-type p53-induced phosphatase 1 (WIP1 or PPM1D) encodes a negative regulator of p53. WIP1 amplification (17q22-q23) and its overexpression have been reported in diverse cancer types. We examined primary medulloblastoma specimens and cell lines, and detected WIP1 copy gain and amplification prevalent among but not exclusively in the tumors with 17q gain and isochromosome 17q (i17q), which are among the most common cytogenetic lesions in medulloblastoma. WIP1 RNA levels were significantly higher in the tumors with 17q gain or i17q. Immunoblots confirmed significant WIP1 protein in primary tumors, generally higher in those with 17q gain or i17q. Under basal growth conditions and in response to the chemotherapeutic agent, etoposide, WIP1 antagonized p53-mediated apoptosis in medulloblastoma cell lines. These results indicate that medulloblastoma express significant levels of WIP1 that modulate genotoxic responsiveness by negatively regulating p53.


Asunto(s)
Regulación Neoplásica de la Expresión Génica/fisiología , Meduloblastoma/metabolismo , Fosfoproteínas Fosfatasas/metabolismo , Adolescente , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Niño , Preescolar , Cromosomas Humanos Par 17 , Femenino , Proteínas Fluorescentes Verdes/biosíntesis , Humanos , Hibridación Fluorescente in Situ/métodos , Etiquetado Corte-Fin in Situ , Lactante , Masculino , Meduloblastoma/genética , Fosfoproteínas Fosfatasas/genética , Proteína Fosfatasa 2C , Estudios Retrospectivos , Transfección/métodos , Proteína p53 Supresora de Tumor/metabolismo
17.
Nat Clin Pract Neurol ; 3(12): 682-93, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18046441

RESUMEN

The overall prognosis for patients with high-grade glioma remains dismal, despite advances in treatment modalities including neurosurgery, radiation therapy and conventional cytotoxic chemotherapy. In this article, we review literature that provides a rationale for the use of antiangiogenic therapy to improve the treatment of high-grade neoplasms in the CNS. In particular, we focus our discussion on the central role of the phosphatidylinositol 3-kinase-Akt- phosphatase and tensin homolog (PI3K-Akt-PTEN) axis as a potential molecular target for the control of angiogenesis in brain tumors via the coordinated control of cell division, tumor growth, angiogenesis, apoptosis, invasion and cellular metabolism in the tumor and stromal compartments. We suggest that instead of inhibiting a single cell surface receptor, thereby leaving other receptors free to pulse survival, proliferative, angiogenic and invasive signals, a more effective way to approach the design of targeted therapy against brain tumors is to inhibit a nodal point where redundant cell surface receptor signals converge to transmit important, relatively conserved signaling events within the cell. The epigenetic and post-translational regulation of PI3K-Akt-PTEN signaling has a prominent role in brain tumor pathogenesis, and we therefore suggest that PI3K could be an important target for therapies that target brain tumors.


Asunto(s)
Neoplasias Encefálicas/enzimología , Neovascularización Patológica/enzimología , Transducción de Señal/fisiología , Animales , Neoplasias Encefálicas/complicaciones , Neoplasias Encefálicas/terapia , Humanos , Neovascularización Patológica/etiología , Fosfohidrolasa PTEN , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-akt
18.
BMC Cancer ; 7: 127, 2007 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-17626635

RESUMEN

BACKGROUND: Medulloblastoma is the most common malignant brain tumor of childhood. Children who relapse usually die of their disease, which reflects resistance to radiation and/or chemotherapy. Improvements in outcome require a better understanding of the molecular basis of medulloblastoma growth and treatment response. TP73 is a member of the TP53 tumor suppressor gene family that has been found to be overexpressed in a variety of tumors and mediates apoptotic responses to genotoxic stress. In this study, we assessed expression of TP73 RNA species in patient tumor specimens and in medulloblastoma cell lines, and manipulated expression of full-length TAp73 and amino-terminal truncated DeltaNp73 to assess their effects on growth. METHODS: We analyzed medulloblastoma samples from thirty-four pediatric patients and the established medulloblastoma cell lines, Daoy and D283MED, for expression of TP73 RNA including the full-length transcript and the 5'-terminal variants that encode the DeltaNp73 isoform, as well as TP53 RNA using quantitative real time-RTPCR. Protein expression of TAp73 and DeltaNp73 was quantitated with immunoblotting methods. Clinical outcome was analyzed based on TP73 RNA and p53 protein expression. To determine effects of overexpression or knock-down of TAp73 and DeltaNp73 on cell cycle and apoptosis, we analyzed transiently transfected medulloblastoma cell lines with flow cytometric and TUNEL methods. RESULTS: Patient medulloblastoma samples and cell lines expressed full-length and 5'-terminal variant TP73 RNA species in 100-fold excess compared to non-neoplastic brain controls. Western immunoblot analysis confirmed their elevated levels of TAp73 and amino-terminal truncated DeltaNp73 proteins. Kaplan-Meier analysis revealed trends toward favorable overall and progression-free survival of patients whose tumors display TAp73 RNA overexpression. Overexpression of TAp73 or DeltaNp73 induced apoptosis under basal growth conditions in vitro and sensitized them to cell death in response to chemotherapeutic agents. CONCLUSION: These results indicate that primary medulloblastomas express significant levels of TP73 isoforms, and suggest that they can modulate the survival and genotoxic responsiveness of medulloblastomas cells.


Asunto(s)
Apoptosis/genética , Neoplasias Cerebelosas/genética , Proteínas de Unión al ADN/genética , Regulación Neoplásica de la Expresión Génica , Meduloblastoma/genética , Proteínas Nucleares/genética , ARN Neoplásico/genética , Proteínas Supresoras de Tumor/genética , Biomarcadores de Tumor/genética , Western Blotting , Línea Celular Tumoral , Supervivencia Celular/genética , Neoplasias Cerebelosas/metabolismo , Neoplasias Cerebelosas/patología , Niño , Preescolar , Progresión de la Enfermedad , Citometría de Flujo , Estudios de Seguimiento , Silenciador del Gen , Humanos , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Lactante , Masculino , Meduloblastoma/metabolismo , Meduloblastoma/patología , Pronóstico , Estudios Retrospectivos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Índice de Severidad de la Enfermedad , Factores de Tiempo
19.
Eur J Cancer ; 43(8): 1308-17, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17467979

RESUMEN

Rhabdomyosarcoma is the most common soft tissue sarcoma of childhood. Improving the management of rhabdomyosarcoma requires a better understanding of growth regulation. Patched haploinsufficient (Ptch+/-) mice spontaneously develop soft tissue sarcomas that resemble human rhabdomyosarcomas. Using microarray profiling and quantitative real-time reverse transcriptase polymerase chain reaction, we identified candidate genes differentially expressed in Ptch+/- mouse rhabdomyosarcoma relative to mature muscle. Overexpressed genes include Secreted Phosphoprotein 1 (Spp1, Osteopontin), and Matrix Metalloproteinases-2 and -14 (Mmp2 and Mmp14). Spp1 is an integrin-binding phosphoglycoprotein upregulated in carcinomas, and Mmps regulate tumour invasion. Immunochemical analyses of murine and human rhabdomyosarcoma specimens confirmed increased expression of Spp1, Mmp2, Mmp14, nuclear factor-kappa B (NF-kappaB) p65 and its phosphorylated active isoform. Neutralising Spp1 antibody decreased Mmp14 RNA in murine rhabdomyosarcoma cultures, indicating a positive regulatory role for extracellular Spp1. Plasma from rhabdomyosarcoma patients display elevated levels of SPP1. These results implicate Spp1, NF-kappaB, and Mmp activation as a putative signalling pathway involved in rhabdomyosarcoma growth.


Asunto(s)
Metaloproteinasas de la Matriz/metabolismo , Proteínas de Neoplasias/metabolismo , Osteopontina/metabolismo , Rabdomiosarcoma/metabolismo , Animales , Western Blotting , ADN Complementario/metabolismo , Ensayo de Inmunoadsorción Enzimática , Expresión Génica , Heterocigoto , Humanos , Inmunohistoquímica , Metaloproteinasas de la Matriz/genética , Ratones , Análisis por Micromatrices , Mutación/genética , Proteínas de Neoplasias/genética , Osteopontina/genética , ARN Neoplásico/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rabdomiosarcoma/genética
20.
BMC Cancer ; 6: 223, 2006 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-16968546

RESUMEN

BACKGROUND: Medulloblastoma is the most common malignant brain tumor of childhood. Improvements in clinical outcome require a better understanding of the genetic alterations to identify clinically significant biological factors and to stratify patients accordingly. In the present study, we applied cytogenetic characterization to guide the identification of biologically significant genes from gene expression microarray profiles of medulloblastoma. METHODS: We analyzed 71 primary medulloblastomas for chromosomal copy number aberrations (CNAs) using comparative genomic hybridization (CGH). Among 64 tumors that we previously analyzed by gene expression microarrays, 27 were included in our CGH series. We analyzed clinical outcome with respect to CNAs and microarray results. We filtered microarray data using specific CNAs to detect differentially expressed candidate genes associated with survival. RESULTS: The most frequent lesions detected in our series involved chromosome 17; loss of 16q, 10q, or 8p; and gain of 7q or 2p. Recurrent amplifications at 2p23-p24, 2q14, 7q34, and 12p13 were also observed. Gain of 8q is associated with worse overall survival (p = 0.0141), which is not entirely attributable to MYC amplification or overexpression. By applying CGH results to gene expression analysis of medulloblastoma, we identified three 8q-mapped genes that are associated with overall survival in the larger group of 64 patients (p < 0.05): eukaryotic translation elongation factor 1D (EEF1D), ribosomal protein L30 (RPL30), and ribosomal protein S20 (RPS20). CONCLUSION: The complementary use of CGH and expression profiles can facilitate the identification of clinically significant candidate genes involved in medulloblastoma growth. We demonstrate that gain of 8q and expression levels of three 8q-mapped candidate genes (EEF1D, RPL30, RPS20) are associated with adverse outcome in medulloblastoma.


Asunto(s)
Cromosomas Humanos Par 8 , Meduloblastoma/genética , Factor 1 de Elongación Peptídica/genética , Proteínas Ribosómicas/genética , Adolescente , Adulto , Niño , Preescolar , Aberraciones Cromosómicas , Cromosomas Humanos Par 2/metabolismo , Amplificación de Genes/fisiología , Dosificación de Gen/fisiología , Genes Relacionados con las Neoplasias/fisiología , Genes myc/fisiología , Humanos , Lactante , Meduloblastoma/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Supervivencia
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