Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 56
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Pediatr Transplant ; 26(3): e14209, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34907641

RESUMO

BACKGROUND: Immunotherapy, specifically immune checkpoint inhibitors (ICIs), including anti-programmed cell death 1 (anti-PD1), has recently received clinical approval for the treatment of adult hepatocellular carcinoma (HCC). However, the safety and efficacy of ICIs prior to solid organ transplant are unknown, especially in pediatrics. Safety reports are variable in adults, with some series describing subsequent allograft rejection and loss while others report successful transplants without allograft rejection.As ICIs stimulate the immune system by blocking the interaction between PD1 and the ligand-receptor pair programmed cell death-ligand 1 (PDL1), the downstream effects of T-cell activation increase the risk of graft rejection. METHODS: Here, we present a case of an adolescent with moderately differentiated non-fibrolamellar HCC treated with pembrolizumab, an anti-PD1 therapy, who subsequently underwent successful orthotopic liver transplantation (OLT). RESULTS: Our patient received an OLT 138 days from the last pembrolizumab dose with graft preservation. The patient has no evidence of recurrent disease or any episode of allograft rejection 48 months post OLT. Staining of tumor and normal tissues from longitudinal specimens finds PDL1 positive Kupffer cells present in normal liver and peritumoral areas with no changes post anti-PD1 therapy. In contrast, tumor cells were negative for PDL1. CONCLUSION: This case represents a basis for optimism in potential use of anti-PD1 therapy in liver transplant candidates and supports further investigation of immune checkpoint inhibitors use in this unique patient population.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Transplante de Fígado , Adolescente , Adulto , Carcinoma Hepatocelular/cirurgia , Criança , Humanos , Inibidores de Checkpoint Imunológico , Ligantes , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/cirurgia
2.
Pediatr Dermatol ; 39(2): 322-323, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35028971

RESUMO

Pigmented epithelioid melanocytoma (PEM) is an intermediate-grade melanocytic tumor with considerable histologic overlap with other melanocytic neoplasms such as epithelioid blue nevus (EBN), which is associated with the neoplastic syndrome Carney complex (CC). Next-generation sequencing is a valuable tool for identifying the primary drivers of melanocytic neoplasms and differentiating them from one another. While germline variants in the protein kinase cAMP-dependent regulatory type 1 alpha (PRKAR1A) gene have been associated with EBN and CC, fusions in protein kinase C-alpha (PRKCA) have been shown as sporadic drivers of PEM. Herein, we report the diagnosis and workup of a case of pigmented epithelioid melanocytoma with a novel protein kinase C-beta (PRKCB) fusion.


Assuntos
Nevo Azul , Neoplasias Cutâneas , Humanos , Nevo Azul/diagnóstico , Nevo Azul/genética , Nevo Azul/patologia , Proteína Quinase C beta , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/cirurgia , Tetraspanina 30
3.
J Cutan Pathol ; 46(2): 159-161, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30468020

RESUMO

We report a case of disseminated Trichosporon asahii in a patient on systemic antifungal therapy who presented with multiple cutaneous nodules suggestive of fungal infection. Histologic features resembled neutrophilic eccrine hidradenitis but staining with periodic acid-Schiff and Gomori methenamine silver confirmed the clinical diagnosis. This case highlights the importance of maintaining suspicion for trichosporonosis and contextualizing histologic findings within the underlying clinical picture.


Assuntos
Dermatomicoses , Leucemia-Linfoma Linfoblástico de Células Precursoras , Tricosporonose , Adolescente , Dermatomicoses/diagnóstico , Dermatomicoses/tratamento farmacológico , Dermatomicoses/patologia , Humanos , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Tricosporonose/diagnóstico , Tricosporonose/tratamento farmacológico , Tricosporonose/patologia
4.
Pediatr Dermatol ; 35(4): e235-e236, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29766561

RESUMO

Indications for everolimus and other drugs within the mammalian target of rapamycin inhibitor class have recently expanded to include tuberous sclerosis complex. Everolimus is generally well tolerated, but it is important for physicians to identify and manage associated cutaneous adverse effects. We report the first case of a child developing erythema nodosum while undergoing everolimus therapy.


Assuntos
Antineoplásicos/efeitos adversos , Eritema Nodoso/induzido quimicamente , Everolimo/efeitos adversos , Esclerose Tuberosa/tratamento farmacológico , Adolescente , Antineoplásicos/uso terapêutico , Everolimo/uso terapêutico , Feminino , Humanos , Pele/patologia
5.
Neurobiol Dis ; 49: 13-21, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22944173

RESUMO

Preventing neuronal death is a priority for treating neurological diseases. However, therapies that inhibit pathological neuron loss could promote tumorigenesis by preventing the physiological death of cancerous cells. To avert this, we targeted the transcriptional upregulation of p21(waf1/cip1) (p21), an endogenous tumor suppressor with neuroprotective and pro-regenerative activity. We identified potential p21 indcuers by screening a FDA-approved drug and natural product small molecule library against hippocampal HT22 cells stably expressing a luciferase reporter driven by the proximal 60bp of the p21 promoter, and tested them for neuroprotection from glutathione depletion mediated oxidative stress, and cytotoxicity to cancer cell lines (DLD-1, Neuro-2A, SH-SY5Y, NGP, CHLA15, CHP212, and SK-N-SH) in vitro. Of the p21 inducers identified, only ciclopirox, a hypoxia-inducible factor prolyl-4-hydroxylase (HIF-PHD) inhibitor, simultaneously protected neurons from glutathione depletion and decreased cancer cell proliferation at concentrations that were not basally toxic to neurons. We found that other structurally distinct HIF-PHD inhibitors (desferrioxamine, 3,4-dihydroxybenzoate, and dimethyloxalyl glycine) also protected neurons at concentrations that killed cancer cells. HIF-PHD inhibitors stabilize HIF transcription factors, mediating genetic adaptation to hypoxia. While augmenting HIF stability is believed to promote tumorigenesis, we found that chronic HIF-PHD inhibition killed cancer cells, suggesting a protumorigenic role for these enzymes. Moreover, our findings suggest that PHD inhibitors can be used to treat neurological disease without significant concern for cell-autonomous tumor promotion.


Assuntos
Antineoplásicos/farmacologia , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Fármacos Neuroprotetores/farmacologia , Inibidores de Prolil-Hidrolase/farmacologia , Animais , Morte Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Células Cultivadas , Ensaios de Seleção de Medicamentos Antitumorais , Hipocampo/efeitos dos fármacos , Hipocampo/fisiologia , Humanos , Camundongos , Camundongos Knockout , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Células PC12 , Ratos , Bibliotecas de Moléculas Pequenas
6.
Heliyon ; 9(6): e17399, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37408891

RESUMO

Purpose: The mortality in patients with MYCN-amplified high-risk neuroblastoma remains greater than 50% despite advances in multimodal therapy. Novel therapies are urgently needed that requires preclinical evaluation in appropriate mice models. Combinatorial treatment with high-dose radiotherapy (HDRT) and immunotherapy has emerged as an effective treatment option in a variety of cancers. Current models of neuroblastoma do not recapitulate the anatomic and immune environment in which multimodal therapies can be effectively tested, and there is a need for an appropriate syngeneic neuroblastoma mice model to study interaction of immunotherapy with host immune cells. Here, we develop a novel syngeneic mouse model of MYCN-amplified neuroblastoma and report the relevance and opportunities of this model to study radiotherapy and immunotherapy. Materials and methods: A syngeneic allograft tumor model was developed using the murine neuroblastoma cell line 9464D derived a tumor from TH-MYCN transgenic mouse. Tumors were generated by transplanting 1 mm3 portions of 9464D flank tumors into the left kidney of C57Bl/6 mice. We investigated the effect of combining HDRT with anti-PD1 antibody on tumor growth and tumor microenvironment. HDRT (8 Gy x 3) was delivered by the small animal radiation research platform (SARRP). Tumor growth was monitored by ultrasound. To assess the effect on immune cells tumors sections were co-imuunostained for six biomarkers using the Vectra multispectral imaging platform. Results: Tumor growth was uniform and confined to the kidney in 100% of transplanted tumors. HDRT was largely restricted to the tumor region with minimal scattered out-of-field dose. Combinatorial treatment with HDRT and PD-1 blockade significantly inhibited tumor growth and prolonged mice survival. We observed augmented T-lymphocyte infiltration, especially CD3+CD8+ lymphocytes, in tumors of mice which received combination treatment. Conclusion: We have developed a novel syngeneic mouse model of MYCN amplified high-risk neuroblastoma. We have utilized this model to show that combining immunotherapy with HDRT inhibits tumor growth and prolongs mice survival.

7.
Cancer Res Commun ; 3(12): 2518-2530, 2023 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-38014922

RESUMO

MYCN-amplified neuroblastoma often presents as a highly aggressive metastatic disease with a poor prognosis. Activating transcription factor 5 (ATF5) is implicated in neural cell differentiation and cancer cell survival. Here, we show that ATF5 is highly expressed in patients with stage 4 high-risk neuroblastoma, with increased expression correlating with a poorer prognosis. We demonstrated that ATF5 promotes the metastasis of neuroblastoma cell lines in vivo. Functionally, ATF5 depletion significantly reduced xenograft tumor growth and metastasis of neuroblastoma cells to the bone marrow and liver. Mechanistically, ATF5 endows tumor cells with resistance to anoikis, thereby increasing their survival in systemic circulation and facilitating metastasis. We identified the proapoptotic BCL-2 modifying factor (BMF) as a critical player in ATF5-regulated neuroblastoma anoikis. ATF5 suppresses BMF under suspension conditions at the transcriptional level, promoting anoikis resistance, whereas BMF knockdown significantly prevents ATF5 depletion-induced anoikis. Therapeutically, we showed that a cell-penetrating dominant-negative ATF5 peptide, CP-d/n-ATF5, inhibits neuroblastoma metastasis to the bone marrow and liver by inducing anoikis sensitivity in circulating tumor cells. Our study identified ATF5 as a metastasis promoter and CP-d/n-ATF5 as a potential antimetastatic therapeutic agent for neuroblastoma. SIGNIFICANCE: This study shows that resistance to anoikis in neuroblastoma is mediated by ATF5 and offers a rationale for targeting ATF5 to treat metastatic neuroblastoma.


Assuntos
Antineoplásicos , Neuroblastoma , Humanos , Anoikis/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico , Neuroblastoma/tratamento farmacológico , Antineoplásicos/farmacologia , Fatores Ativadores da Transcrição
8.
Oncologist ; 16(11): 1614-25, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22042784

RESUMO

Angiogenesis is a target shared by both adult epithelial cancers and the mesenchymal or embryonal tumors of childhood. Development of antiangiogenic agents for the pediatric population has been complicated by largely theoretical concern for toxicities specific to the growing child and prioritization among the many antiangiogenic agents being developed for adults. This review summarizes the mechanism of action and preclinical data relevant to childhood cancers and early-phase clinical trials in childhood solid tumors. Single-agent adverse event profiles in adults and children are reviewed with emphasis on cardiovascular, bone health, and endocrine side effects. In addition, pharmacological factors that may be relevant for prioritizing clinical trials of these agents in children are reviewed. Considerations for further clinical evaluation should include preclinical data, relative potency, efficacy in adults, and the current U.S. Food and Drug Administration approval status. Toxicity profiles of vascular endothelial growth factor (VEGF) signaling pathway inhibitors may be age dependent and ultimately, their utility in the treatment of childhood cancer will require combination with standard cytotoxic drugs or other molecularly targeted agents. In combination studies, toxicity profiles, potential drug interactions, and late effects must be considered. Studies to assess the long-term impact of VEGF signaling pathway inhibitors on cardiovascular, endocrine, and bone health in children with cancer are imperative if these agents are to be administered to growing children and adolescents with newly diagnosed cancers.


Assuntos
Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Adolescente , Antineoplásicos/uso terapêutico , Criança , Feminino , Humanos , Masculino , Fator A de Crescimento do Endotélio Vascular/metabolismo
9.
BMC Cancer ; 11: 529, 2011 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-22208948

RESUMO

BACKGROUND: The biological mechanisms underlying cancer cell motility and invasiveness remain unclear, although it has been hypothesized that they involve some type of epithelial-mesenchymal transition (EMT). METHODS: We used xenograft models of human cancer cells in immunocompromised mice, profiling the harvested tumors separately with species-specific probes and computationally analyzing the results. RESULTS: Here we show that human cancer cells express in vivo a precise multi-cancer invasion-associated gene expression signature that prominently includes many EMT markers, among them the transcription factor Slug, fibronectin, and α-SMA. We found that human, but not mouse, cells express the signature and Slug is the only upregulated EMT-inducing transcription factor. The signature is also present in samples from many publicly available cancer gene expression datasets, suggesting that it is produced by the cancer cells themselves in multiple cancer types, including nonepithelial cancers such as neuroblastoma. Furthermore, we found that the presence of the signature in human xenografted cells was associated with a downregulation of adipocyte markers in the mouse tissue adjacent to the invasive tumor, suggesting that the signature is triggered by contextual microenvironmental interactions when the cancer cells encounter adipocytes, as previously reported. CONCLUSIONS: The known, precise and consistent gene composition of this cancer mesenchymal transition signature, particularly when combined with simultaneous analysis of the adjacent microenvironment, provides unique opportunities for shedding light on the underlying mechanisms of cancer invasiveness as well as identifying potential diagnostic markers and targets for metastasis-inhibiting therapeutics.


Assuntos
Transição Epitelial-Mesenquimal/genética , Neoplasias/metabolismo , Fatores de Transcrição/metabolismo , Animais , Linhagem Celular Tumoral , Colágeno Tipo XI/metabolismo , Perfilação da Expressão Gênica , Humanos , Camundongos , Análise em Microsséries , Invasividade Neoplásica/genética , Neoplasias/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Fatores de Transcrição da Família Snail , Especificidade da Espécie
10.
J Pediatr Hematol Oncol ; 33(5): 390-1, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21552148

RESUMO

Cancer of the colon is the second most common visceral cancer in the United States (lung cancer is the first). It is usually diagnosed in patients older than 40 years, with a peak incidence at 70 years of age. Rarely, are cases seen in the pediatric population. In this study, we report a case of a 13-year-old girl with an 11-month history of intermittent abdominal pain whose diagnosis was delayed due to vague symptoms and a low index of suspicion for this condition.


Assuntos
Dor Abdominal/diagnóstico por imagem , Adenocarcinoma/diagnóstico por imagem , Carcinoma de Células em Anel de Sinete/diagnóstico por imagem , Neoplasias Retroperitoneais/diagnóstico por imagem , Dor Abdominal/patologia , Dor Abdominal/cirurgia , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Adolescente , Carcinoma de Células em Anel de Sinete/patologia , Carcinoma de Células em Anel de Sinete/cirurgia , Evolução Fatal , Feminino , Humanos , Estadiamento de Neoplasias , Neoplasias Retroperitoneais/patologia , Neoplasias Retroperitoneais/cirurgia , Tomografia Computadorizada por Raios X
11.
Int J Radiat Oncol Biol Phys ; 106(4): 857-866, 2020 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-31759078

RESUMO

PURPOSE: The aim of this study is to characterize the effects of high-dose radiation therapy (HDRT) on Notch signaling components of the tumor vasculature. METHODS AND MATERIALS: Human umbilical vein endothelial cells monolayers were exposed to different single fraction doses of irradiation; ribonucleic acid RNA was isolated and polymerase chain reaction was performed for Notch signaling components. The vascular response to radiation therapy was examined in a xenograft model of neuroblastoma. Tumors were treated with 0 Gy, 2 Gy, and 12 Gy single fraction doses and analyzed by double immunofluorescence staining for Notch1, Notch ligands Jagged1 and Dll4, and the endothelial cell (EC) marker endomucin. To assess the role of Notch in vivo, NGP xenograft tumors expressing Fc or Notch1-1-24-decoy (a novel Notch inhibitor) were treated with 0 Gy and 12 Gy. Immunofluorescence staining for endomucin and endomucin/αSMA was performed to analyze the effect of combination treatment on tumor EC and endothelial-to-mesenchymal-transition (EndMT), respectively. RESULTS: In human umbilical vein endothelial cells monolayers doses ≥8 Gy increased expression of NOTCH1, JAG1, and Notch target genes HEY1 and HEY2 as early as 6 hours after irradiation. In vivo, 12 Gy significantly increased Notch1 and Jagged1 in tumor ECs compared with 0 Gy or 2 Gy after 72 hours. Combining HDRT with Notch inhibition using the Notch1-1-24-decoy resulted in a greater loss of EC coverage of tumor vessels than HDRT alone at 6 hours and 72 hours post treatment. Notch inhibition reduced EndMT induced by HDRT, as indicated by diminished αSMA staining in ECs. CONCLUSIONS: HDRT induced Notch1 expression and increased Notch1 signaling in the endothelial component of tumor vasculature, which was not observed with lower doses. This increase in Notch1 activation might protect tumor vessels from HDRT induced damage and regulate EndMT process.


Assuntos
Neovascularização Patológica/metabolismo , Doses de Radiação , Receptor Notch1/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Linhagem Celular Tumoral , Transformação Celular Neoplásica , Transição Epitelial-Mesenquimal/efeitos da radiação , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Endoteliais da Veia Umbilical Humana/efeitos da radiação , Humanos , Proteína Jagged-1/metabolismo , Camundongos , Camundongos Nus , Neovascularização Patológica/patologia , Neovascularização Patológica/radioterapia , Dosagem Radioterapêutica , Proteínas Repressoras/metabolismo , Transdução de Sinais/efeitos da radiação
12.
Mol Cancer Res ; 6(1): 1-9, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18234958

RESUMO

Vascular endothelial growth factor (VEGF) blockade has been validated clinically as a treatment for human cancers, yet virtually all patients eventually develop progressive disease during therapy. In order to dissect this phenomenon, we examined the effect of sustained VEGF blockade in a model of advanced pediatric cancer. Treatment of late-stage hepatoblastoma xenografts resulted in the initial collapse of the vasculature and significant tumor regression. However, during sustained treatment, vessels recovered, concurrent with a striking increase in tumor expression of perlecan, a heparan sulfate proteoglycan. Whereas VEGF mRNA was expressed at the periphery of surviving clusters of tumor cells, both secreted VEGF and perlecan accumulated circumferential to central vessels. Vascular expression of heparanase, VEGF receptor-2 ligand binding, and receptor activation were concurrently maintained despite circulating unbound VEGF Trap. Endothelial survival signaling via Akt persisted. These findings provide a novel mechanism for vascular survival during sustained VEGF blockade and indicate a role for extracellular matrix molecules that sequester and release biologically active VEGF.


Assuntos
Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Colágeno/metabolismo , Células Endoteliais/enzimologia , Células Endoteliais/metabolismo , Ativação Enzimática , Feminino , Regulação Neoplásica da Expressão Gênica , Glucuronidase/metabolismo , Proteoglicanas de Heparan Sulfato/metabolismo , Hepatoblastoma/irrigação sanguínea , Hepatoblastoma/enzimologia , Hepatoblastoma/genética , Hepatoblastoma/patologia , Humanos , Camundongos , Camundongos Nus , Modelos Biológicos , Estadiamento de Neoplasias , Neoplasias/irrigação sanguínea , Neoplasias/enzimologia , Neoplasias/patologia , Neovascularização Patológica/genética , Fosforilação , Ligação Proteica , Proteínas Proto-Oncogênicas c-akt/metabolismo , Indução de Remissão , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Int J Oncol ; 34(2): 401-7, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19148474

RESUMO

Most children with neuroblastoma presenting after infancy have metastatic, chemoresistant disease. Amplification of the MYCN proto-oncogene is a significant marker of these poor-prognosis neuroblastoma tumors. Recent studies suggest that MYCN may function in part by promoting angiogenesis via vascular endothelial growth factor (VEGF). VEGF blockade has been validated as a therapeutic strategy in adult cancers. In these studies, we asked whether inhibition of VEGF signaling via VEGFR2 blockade in established MYCN-amplified neuroblastoma xenografts would: 1) restrict tumor growth; 2) induce hypoxia; and 3) alter tumor vasculature. The MYCN-amplified neuroblastoma human cell line NGP was implanted intrarenally in athymic female mice. After 5 weeks, mice with established tumors were selected, a cohort euthanized to provide day 0 controls, and the rest assigned to receive biweekly injections of DC101 (anti-murine VEGFR2 antibody) or vehicle. DC101 treatment did not inhibit progressive tumor growth in established NGP xenografts. Although tumor vasculature was not significantly disrupted, a modest increase in tumor hypoxia was demonstrated by pimonidazole staining, and expression of a previously described hypoxia metagene was increased by gene set enrichment analysis (GSEA) in DC101-treated tumors. DC101 treatment elicited increased: 1) expression of VEGFR1 and its ligand placental growth factor; and 2) increased Notch activation in tumor vasculature concurrent with expression of the Notch ligand Jagged1. This result suggests that established MYCN-amplified neuroblastoma tumors are relatively VEGF-independent, and display the ability to rapidly up-regulate hypoxia-responsive alternative proangiogenic mechanisms that may stabilize vasculature when VEGF is deficient.


Assuntos
Neovascularização Patológica/patologia , Neuroblastoma/irrigação sanguínea , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/fisiologia , Animais , Divisão Celular , Hipóxia Celular , Feminino , Humanos , Imuno-Histoquímica , Camundongos , Camundongos Nus , Proto-Oncogene Mas , Transplante Heterólogo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores
14.
Int J Oncol ; 34(1): 79-87, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19082480

RESUMO

Approval of the anti-vascular endothelial growth factor (VEGF) antibody bevacizumab by the FDA in 2004 reflected the success of this vascular targeting strategy in extending survival in patients with advanced cancers. However, consistent with previous reports that experimental tumors can grow or recur during VEGF blockade, it has become clear that many patients treated with VEGF inhibitors will ultimately develop progressive disease. Previous studies have shown that disruption of VEGF signaling in tumors induces remodeling in surviving vessels, and link increased expression of angiopoietin-1 (Ang-1) with this process. However, overexpression of Ang-1 in different tumors has yielded divergent results, restricting angiogenesis in some systems while promoting it in others. These data raise the possibility that effects of Ang-1/Tie-2 may be context-dependent. Expression of an Ang-1 construct (Ang1*) did not significantly change tumor growth in our model prior to treatment, although vessels exhibited changes consistent with increased Tie-2 signaling. During inhibition of VEGF, however, both overexpression of Ang1* and administration of an engineered Ang-1 agonist (Bow-Ang1) strikingly protected tumors and vasculature from regression. In this context, Ang-1/Tie-2 activation limited tumor hypoxia, increased vessel caliber, and promoted recruitment of mural cells. Thus, these studies support a model in which activation of Tie-2 is important for tumor and vessel survival when VEGF-dependent vasculature is stressed. Understanding such mechanisms of adaptation to this validated form of therapy may be important in designing regimens that make the best use of this approach.


Assuntos
Angiopoietina-1/genética , Regulação da Expressão Gênica/fisiologia , Neoplasias Renais/irrigação sanguínea , Neovascularização Patológica/patologia , Receptor TIE-2/genética , Sarcoma de Ewing/irrigação sanguínea , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Western Blotting , Hipóxia Celular , Linhagem Celular Tumoral , Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Regulação Neoplásica da Expressão Gênica , Humanos , Imunoprecipitação , Neoplasias Renais/patologia , Camundongos , Camundongos Nus , Fosforilação , Reação em Cadeia da Polimerase , Sarcoma de Ewing/patologia , Transfecção , Transplante Heterólogo , Fator A de Crescimento do Endotélio Vascular/metabolismo
15.
Pediatr Blood Cancer ; 52(5): 669-71, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19101996

RESUMO

Bevacizumab is a monoclonal antibody targeting vascular endothelial growth factor (VEGF). Hypertension is a well-recognized, common side effect of VEGF blocking agents. The reversible posterior leukoencephalopathy syndrome (RPLS) has been described as a rare but serious consequence of bevacizumab administration. We present a case of a 6-year-old child with refractory hepatoblastoma who developed hypertensive crisis, seizures and MRI changes consistent with RPLS while receiving bevacizumab with gemcitabine and oxaliplatin. Findings completely resolved without neurologic sequelae with stringent blood-pressure control. Better understanding of risk for RPLS, prompt recognition and aggressive management will be required as bevacizumab gains wider use in pediatrics.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Imunoterapia , Síndrome da Leucoencefalopatia Posterior/tratamento farmacológico , Síndrome da Leucoencefalopatia Posterior/imunologia , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais Humanizados , Bevacizumab , Pressão Sanguínea/efeitos dos fármacos , Pré-Escolar , Evolução Fatal , Humanos , Imunoterapia/efeitos adversos , Imageamento por Ressonância Magnética , Masculino , Estadiamento de Neoplasias , Síndrome da Leucoencefalopatia Posterior/patologia , Síndrome da Leucoencefalopatia Posterior/fisiopatologia
16.
Pediatr Radiol ; 39(7): 723-6, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19430769

RESUMO

An association between neuroblastoma and opsoclonus-myoclonus syndrome (OMS) was described as early as 1927 within the first report on the transformation of malignant neuroblastoma to a benign ganglioneuroma. It was not recognized at that time nor was it appreciated in the subsequent follow-up report on the same patient in 1959. Myoclonic encephalopathy of infancy, an alternative name for OMS, was described by a pediatric neurologist in 1962; however, its connection to neuroblastoma was not known. It was only in 1968 that the association between these two conditions was first reported. The neuroblastoma tumors associated with OMS are almost all small, stage I-II with no associated MYCN amplification or metastases. OMS occurs in 2-3% of patients with neuroblastoma, but neuroblastoma is found in as many as 50% of children who present with OMS. Nearly 100% of the children with neuroblastoma associated with OMS survive, and this has led to speculation that the OMS is a result of an autoimmune process, not metastases. Affected children are treated with steroids, ACTH, or intravenous immunoglobulin, but many have persistent neurologic and developmental deficits. Using the original case reported in 1927, we summarize a century of literature in this review on OMS and its association with neuroblastoma.


Assuntos
Diagnóstico por Imagem/história , Neuroblastoma/diagnóstico , Neuroblastoma/história , Síndrome de Opsoclonia-Mioclonia/diagnóstico , Síndrome de Opsoclonia-Mioclonia/história , Pediatria/história , Radiologia/história , Criança , História do Século XX , História do Século XXI , Humanos , Estados Unidos
17.
Cancers (Basel) ; 11(12)2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31835848

RESUMO

The clinical management of pediatric liver tumors involves stratification into risk groups. One previously defined, high-risk group of hepatoblastomas is the small cell undifferentiated variant. In light of molecular studies showing SMARCB1 deletion in these tumors, it is now recognized that most small cell, undifferentiated liver tumors represent an aggressive unrelated tumor-the malignant rhabdoid tumor (MRT). SMARCB1 is a member of the chromatin remodeling SWI/SNF complex and encodes the INI1 protein. The histologic diagnosis of MRT is currently based on INI1 negative immunoreactivity and the presence of rhabdoid morphology. INI1-negative small cell liver tumors lacking classic rhabdoid morphology are often misclassified as small cell undifferentiated hepatoblastomas (SCUD-HB), according to the current classification. Pediatric liver tumors diagnosed between 2003-2017 as SCUD-HB (four cases) or MRT (two cases) were identified from the Columbia University Pathology Department Archives. All tumors were associated with normal or low serum alpha fetoprotein levels, and showed an absence of immunohistochemical staining of hepatocellular markers (Hep-par1, Arginase) and loss of INI1 staining. Two cases were initially diagnosed as MRT, one with prominent rhabdoid morphology, the other with predominant small cell morphology. The remaining four cases with small cell morphology were classified as SCUD-HB. Ancillary molecular studies confirmed the loss of SMARCB1, supporting the diagnosis of MRT in all cases, proving morphology an unreliable criterion. It is critical to eliminate the term INI1-negative hepatoblastoma from the current classification scheme, and classify INI1-negative tumors as MRT, particularly since high-risk HB-chemotherapy regimens are not effective for treating MRT.

18.
Cancer Res ; 66(8): 4378-84, 2006 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-16618763

RESUMO

Much evidence supports an important role for the inducible enzyme cyclooxygenase-2 (COX-2) in tumor angiogenesis. Previous studies have focused on the role of COX-2 in stimulating endothelial proliferation, with blockade of this enzyme impairing endothelial homeostasis. However, recent data suggest that COX-2 also regulates molecules implicated in endothelial trafficking with pericytes/vascular mural cells (VMC), an interaction crucial to vessel stability. We investigated the role of COX-2 in vascular assembly by testing the effect of the specific COX-2 inhibitor SC-236 in an orthotopic xenograft model of human Wilms' tumor. Tumor growth was significantly suppressed by SC-236 (78% at day 28, 55% at day 35). Perfusion studies and immunostaining showed a marked decrease in vasculature, particularly in small vessels. Specifically, SC-236 inhibited participation of VMC in xenograft vessels. SC-236-treated tumors developed segmentally dilated, architecturally erratic tumor vessels with decreased nascent pericytes and scant mature VMC. Although vascular endothelial growth factor expression was unchanged, expression of the chemokine receptor CXCR4 was decreased in tumor vessels, consistent with defective homing of vascular progenitor cells. Vascular expression of phosphorylated platelet-derived growth factor receptor-beta was also diminished, indicating impaired VMC-endothelial trafficking. Consistent with the key role of this interaction in vessel homeostasis, vascular cells in SC-236-treated tumors displayed markedly diminished phosphorylated Akt, indicating disrupted survival signaling. These results show that SC-236 causes defective vascular assembly by attenuating incorporation of VMC into tumor vessels, impairing endothelial survival, and raise the possibility that blockade of COX-2 may provide therapeutic synergies with antiangiogenic molecules that more selectively target endothelial cells.


Assuntos
Inibidores de Ciclo-Oxigenase 2/farmacologia , Pirazóis/farmacologia , Sulfonamidas/farmacologia , Tumor de Wilms/irrigação sanguínea , Tumor de Wilms/tratamento farmacológico , Animais , Feminino , Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Camundongos Nus , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/enzimologia , Neovascularização Patológica/patologia , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-sis/metabolismo , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Receptores CXCR4/biossíntese , Receptores CXCR4/deficiência , Fator A de Crescimento do Endotélio Vascular/biossíntese , Tumor de Wilms/enzimologia , Tumor de Wilms/genética , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Oncogene ; 37(40): 5451-5465, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29880876

RESUMO

Despite the identification of MYCN amplification as an adverse prognostic marker in neuroblastoma, MYCN inhibitors have yet to be developed. Here, by integrating evidence from a whole-genome shRNA library screen and the computational inference of master regulator proteins, we identify transcription factor activating protein 4 (TFAP4) as a critical effector of MYCN amplification in neuroblastoma, providing a novel synthetic lethal target. We demonstrate that TFAP4 is a direct target of MYCN in neuroblastoma cells, and that its expression and activity strongly negatively correlate with neuroblastoma patient survival. Silencing TFAP4 selectively inhibits MYCN-amplified neuroblastoma cell growth both in vitro and in vivo, in xenograft mouse models. Mechanistically, silencing TFAP4 induces neuroblastoma differentiation, as evidenced by increased neurite outgrowth and upregulation of neuronal markers. Taken together, our results demonstrate that TFAP4 is a key regulator of MYCN-amplified neuroblastoma and may represent a valuable novel therapeutic target.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Proteína Proto-Oncogênica N-Myc/metabolismo , Neuroblastoma/patologia , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/deficiência , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Diferenciação Celular , Linhagem Celular Tumoral , Proliferação de Células , Proteínas de Ligação a DNA , Regulação Neoplásica da Expressão Gênica , Inativação Gênica , Humanos , Camundongos , Proteínas de Ligação a RNA
20.
Front Pediatr ; 5: 114, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28638817

RESUMO

We report a rare case of an 18-month-old female with autosomal recessive polycystic kidney disease, Caroli syndrome, and pure fetal type hepatoblastoma. The liver tumor was surgically resected with no chemotherapy given. Now 9 years post resection she demonstrates no local or distant recurrence and stable renal function.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA