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1.
Mov Disord ; 39(6): 983-995, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38581205

RESUMO

BACKGROUND: Based on a limited number of reported families, biallelic CA8 variants have currently been associated with a recessive neurological disorder named, cerebellar ataxia, mental retardation, and dysequilibrium syndrome 3 (CAMRQ-3). OBJECTIVES: We aim to comprehensively investigate CA8-related disorders (CA8-RD) by reviewing existing literature and exploring neurological, neuroradiological, and molecular observations in a cohort of newly identified patients. METHODS: We analyzed the phenotype of 27 affected individuals from 14 families with biallelic CA8 variants (including data from 15 newly identified patients from eight families), ages 4 to 35 years. Clinical, genetic, and radiological assessments were performed, and zebrafish models with ca8 knockout were used for functional analysis. RESULTS: Patients exhibited varying degrees of neurodevelopmental disorders (NDD), along with predominantly progressive cerebellar ataxia and pyramidal signs and variable bradykinesia, dystonia, and sensory impairment. Quadrupedal gait was present in only 10 of 27 patients. Progressive selective cerebellar atrophy, predominantly affecting the superior vermis, was a key diagnostic finding in all patients. Seven novel homozygous CA8 variants were identified. Zebrafish models demonstrated impaired early neurodevelopment and motor behavior on ca8 knockout. CONCLUSION: Our comprehensive analysis of phenotypic features indicates that CA8-RD exhibits a wide range of clinical manifestations, setting it apart from other subtypes within the category of CAMRQ. CA8-RD is characterized by cerebellar atrophy and should be recognized as part of the autosomal-recessive cerebellar ataxias associated with NDD. Notably, the presence of progressive superior vermis atrophy serves as a valuable diagnostic indicator. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.


Assuntos
Ataxia Cerebelar , Peixe-Zebra , Humanos , Ataxia Cerebelar/genética , Criança , Adolescente , Masculino , Feminino , Pré-Escolar , Animais , Adulto , Adulto Jovem , Anoctaminas/genética , Deficiência Intelectual/genética , Fenótipo , Transtornos do Neurodesenvolvimento/genética
2.
Gene Ther ; 28(5): 242-255, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-32541928

RESUMO

Neutralising antibodies (NAbs), caused by past adeno-associated virus (AAV) infection, represent a critical challenge for AAV-mediated gene therapy, with even low NAb titres capable of inhibiting gene transfer, however in protein-rich environments such as the vitreous it is expected that other constituents could also interact with the transduction process. Inhibition of AAV2/2, AAV2/5, AAV2/6 and AAV2/8 transduction by human vitreous humour (VH) obtained from 80 post-mortem eye cups was investigated in this report, with clinically relevant vitreous dilutions as low as 1:2. Unexpectedly, the highest prevalence of inhibition of transduction was observed against AAV2/6, with 66% of tested samples displaying neutralisation at a 1:2 VH dilution. Only two samples showed inhibition of AAV2/8, indicating this serotype is an attractive vector for use in non-vitrectomised eyes of unscreened individuals. Levels of anti-AAV NAbs observed in the VH were much lower than previously observed in serum of a similar Australian population. Among ten tested eye cup pairs, we observed only small variation in anti-AAV NAbs levels between the left and right eye cups. Interaction with 1:2 diluted VH had an augmentation effect on AAV2/8 transduction (p = 0.004), a phenomenon which was not due to albumin or transferrin and which, if developed, might benefit the use of AAV2/8 in clinical settings.


Assuntos
Dependovirus , Corpo Vítreo , Austrália , Dependovirus/genética , Terapia Genética , Vetores Genéticos/genética , Humanos , Transdução Genética
3.
J Neurooncol ; 146(1): 41-53, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31760595

RESUMO

INTRODUCTION: Malignant astrocytomas are composed of heterogeneous cell populations. Compared to grade IV glioblastoma, low-grade astrocytomas have more differentiated cells and are associated with a better prognosis. Therefore, inducing cellular differentiation to alter the behaviour of high-grade astrocytomas may serve as a therapeutic strategy. The nuclear factor one (NFI) transcription factors are essential for normal astrocytic differentiation. Here, we investigate whether family members NFIA and NFIB act as effectors of cellular differentiation in glioblastoma. METHODS: We analysed expression of NFIA and NFIB in mRNA expression data of high-grade astrocytoma and with immunofluorescence co-staining. Furthermore, we induced NFI expression in patient-derived subcutaneous glioblastoma xenografts via in vivo electroporation. RESULTS: The expression of NFIA and NFIB is reduced in glioblastoma as compared to lower grade astrocytomas. At a cellular level, their expression is associated with differentiated and mature astrocyte-like tumour cells. In vivo analyses consistently demonstrate that expression of either NFIA or NFIB is sufficient to promote tumour cell differentiation in glioblastoma xenografts. CONCLUSION: Our findings indicate that both NFIA and NFIB may have an endogenous pro-differentiative function in astrocytomas, similar to their role in normal astrocyte differentiation. Overall, our study establishes a basis for further investigation of targeting NFI-mediated differentiation as a potential differentiation therapy.


Assuntos
Biomarcadores Tumorais/metabolismo , Diferenciação Celular , Glioblastoma/patologia , Fatores de Transcrição NFI/metabolismo , Animais , Apoptose , Biomarcadores Tumorais/genética , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Glioblastoma/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Fatores de Transcrição NFI/genética , Gradação de Tumores , Neurogênese , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
4.
J Neurochem ; 149(4): 535-550, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30592774

RESUMO

Targeting epigenetic mechanisms has shown promise against several cancers but has so far been unsuccessful against glioblastoma (GBM). Altered histone 3 lysine 4 methylation and increased lysine-specific histone demethylase 1A (LSD1) expression in GBM tumours nonetheless suggest that epigenetic mechanisms are involved in GBM. We engineered a dual-action prodrug, which is activated by the high hydrogen peroxide levels associated with GBM cells. This quinone methide phenylaminecyclopropane prodrug releases the LSD1 inhibitor 2-phenylcyclopropylamine with the glutathione scavenger para-quinone methide to trigger apoptosis in GBM cells. Quinone methide phenylaminocyclopropane impaired GBM cell behaviours in two-dimensional and three-dimensional assays, and triggered cell apoptosis in several primary and immortal GBM cell cultures. These results support our double-hit hypothesis of potentially targeting LSD1 and quenching glutathione, in order to impair and kill GBM cells but not healthy astrocytes. Our data suggest this strategy is effective at selectively targeting GBM and potentially other types of cancers. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Pró-Fármacos/farmacologia , Compostos de Anilina/farmacologia , Células Cultivadas , Ciclopropanos/farmacologia , Desenho de Fármacos , Glutationa/antagonistas & inibidores , Histona Desmetilases/antagonistas & inibidores , Humanos , Indolquinonas/farmacologia
5.
Acta Neuropathol ; 138(6): 1033-1052, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31463571

RESUMO

Glioblastomas (GBMs) are malignant central nervous system (CNS) neoplasms with a very poor prognosis. They display cellular hierarchies containing self-renewing tumourigenic glioma stem cells (GSCs) in a complex heterogeneous microenvironment. One proposed GSC niche is the extracellular matrix (ECM)-rich perivascular bed of the tumour. Here, we report that the ECM binding dystroglycan (DG) receptor is expressed and functionally glycosylated on GSCs residing in the perivascular niche. Glycosylated αDG is highly expressed and functional on the most aggressive mesenchymal-like (MES-like) GBM tumour compartment. Furthermore, we found that DG acts to maintain an MES-like state via tight control of MAPK activation. Antibody-based blockade of αDG induces robust ERK-mediated differentiation leading to reduced GSC potential. DG was shown to be required for tumour initiation in MES-like GBM, with constitutive loss significantly delaying or preventing tumourigenic potential in-vivo. These findings reveal a central role of the DG receptor, not only as a structural element, but also as a critical factor promoting MES-like GBM and the maintenance of GSCs residing in the perivascular niche.


Assuntos
Neoplasias Encefálicas/metabolismo , Distroglicanas/metabolismo , Glioma/metabolismo , Células-Tronco Neoplásicas/metabolismo , Microambiente Tumoral/fisiologia , Animais , Neoplasias Encefálicas/irrigação sanguínea , Neoplasias Encefálicas/cirurgia , Transformação Celular Neoplásica , Células Cultivadas , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Glioma/irrigação sanguínea , Glioma/cirurgia , Humanos , Camundongos Endogâmicos NOD , Camundongos SCID , Transplante de Neoplasias
6.
BMC Cancer ; 19(1): 157, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30777055

RESUMO

BACKGROUND: Glioblastoma (GBM) is the most common and aggressive type of primary brain cancer. With median survival of less than 15 months, identification and validation of new GBM therapeutic targets is of critical importance. RESULTS: In this study we tested expression and performed pharmacological characterization of the calcitonin receptor (CTR) as well as other members of the calcitonin family of receptors in high-grade glioma (HGG) cell lines derived from individual patient tumours, cultured in defined conditions. Previous immunohistochemical data demonstrated CTR expression in GBM biopsies and we were able to confirm CALCR (gene encoding CTR) expression. However, as assessed by cAMP accumulation assay, only one of the studied cell lines expressed functional CTR, while the other cell lines have functional CGRP (CLR/RAMP1) receptors. The only CTR-expressing cell line (SB2b) showed modest coupling to the cAMP pathway and no activation of other known CTR signaling pathways, including ERK1/2 and p38 MAP kinases, and Ca2+ mobilization, supportive of low cell surface receptor expression. Exome sequencing data failed to account for the discrepancy between functional data and expression on the cell lines that do not respond to calcitonin(s) with no deleterious non-synonymous polymorphisms detected, suggesting that other factors may be at play, such as alternative splicing or rapid constitutive receptor internalisation. CONCLUSIONS: This study shows that GPCR signaling can display significant variation depending on cellular system used, and effects seen in model recombinant cell lines or tumour cell lines are not always reproduced in a more physiologically relevant system and vice versa.


Assuntos
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Glioblastoma/genética , Glioblastoma/metabolismo , Receptores da Calcitonina/genética , Receptores da Calcitonina/metabolismo , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/mortalidade , Proteína Semelhante a Receptor de Calcitonina/genética , Proteína Semelhante a Receptor de Calcitonina/metabolismo , Técnicas de Cultura de Células , Proliferação de Células , Glioblastoma/mortalidade , Humanos , Pessoa de Meia-Idade , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosforilação , Proteína 1 Modificadora da Atividade de Receptores/genética , Proteína 2 Modificadora da Atividade de Receptores/genética , Transdução de Sinais , Análise de Sobrevida , Transcriptoma , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
7.
Pharmacol Res ; 134: 166-178, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29944980

RESUMO

In the field of kinase inhibitors for applications in cancer research, tubulin is emerging as a targeted cellular protein that can significantly contribute to their activities. However, investigation of kinase inhibitors beyond the kinome is an area often neglected. Herein, we describe the results of pharmacological studies using drugs targeting kinases, tubulin or both. A key finding is that if cells are treated with a kinase inhibitor unintentionally targeting tubulin, their characteristic shape will diminish within a short timeframe. These changes in cell morphology are not seen when cells are treated with bona fide kinase inhibitors that do not directly target tubulin. Thus, early changes in cell morphology upon treatments are a strong indication that the inhibitor is directly targeting tubulin. Recognizing tubulin as a target of kinase inhibitors will build confidence in the future mechanistic studies using kinase inhibitors.


Assuntos
Antineoplásicos/farmacologia , Forma Celular/efeitos dos fármacos , Microtúbulos/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Células-Tronco Neoplásicas/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/metabolismo , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Microtúbulos/metabolismo , Microtúbulos/patologia , Neoplasias/enzimologia , Neoplasias/patologia , Células-Tronco Neoplásicas/enzimologia , Células-Tronco Neoplásicas/patologia , Fatores de Tempo
8.
Cancer Immunol Immunother ; 66(9): 1217-1228, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28501939

RESUMO

We have reported that calcitonin receptor (CTR) is widely expressed in biopsies from the lethal brain tumour glioblastoma by malignant glioma and brain tumour-initiating cells (glioma stem cells) using anti-human CTR antibodies. A monoclonal antibody against an epitope within the extracellular domain of CTR was raised (mAb2C4) and chemically conjugated to either plant ribosome-inactivating proteins (RIPs) dianthin-30 or gelonin, or the drug monomethyl auristatin E (MMAE), and purified. In the high-grade glioma cell line (HGG, representing glioma stem cells) SB2b, in the presence of the triterpene glycoside SO1861, the EC50 for mAb2C4:dianthin was 10.0 pM and for mAb2C4:MMAE [antibody drug conjugate (ADC)] 2.5 nM, 250-fold less potent. With the cell line U87MG, in the presence of SO1861, the EC50 for mAb2C4:dianthin was 20 pM, mAb2C4:gelonin, 20 pM, compared to the ADC (6.3 nM), which is >300 less potent. Several other HGG cell lines that express CTR were tested and the efficacies of mAb2C4:RIP (dianthin or gelonin) were similar. Co-administration of the enhancer SO1861 purified from plants enhances lysosomal escape. Enhancement with SO1861 increased potency of the immunotoxin (>3 log values) compared to the ADC (1 log). The uptake of antibody was demonstrated with the fluorescent conjugate mAb2C4:Alexa Fluor 568, and the release of dianthin-30:Alexa Fluor488 into the cytosol following addition of SO1861 supports our model. These data demonstrate that the immunotoxins are highly potent and that CTR is an effective target expressed by a large proportion of HGG cell lines representative of glioma stem cells and isolated from individual patients.


Assuntos
Anticorpos Monoclonais/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Glioblastoma/tratamento farmacológico , Oligopeptídeos/farmacologia , Receptores da Calcitonina/antagonistas & inibidores , Proteínas Inativadoras de Ribossomos Tipo 1/farmacologia , Anticorpos Monoclonais/imunologia , Linhagem Celular Tumoral , Humanos , Receptores da Calcitonina/imunologia , Células Tumorais Cultivadas
9.
J Neurosci ; 34(8): 2921-30, 2014 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-24553933

RESUMO

Epigenetic mechanisms are essential in regulating neural progenitor cell self-renewal, with the chromatin-modifying protein Enhancer of zeste homolog 2 (EZH2) emerging as a central player in promoting progenitor cell self-renewal during cortical development. Despite this, how Ezh2 is itself regulated remains unclear. Here, we demonstrate that the transcription factor nuclear factor IB (NFIB) plays a key role in this process. Nfib(-/-) mice exhibit an increased number of proliferative ventricular zone cells that express progenitor cell markers and upregulation of EZH2 expression within the neocortex and hippocampus. NFIB binds to the Ezh2 promoter and overexpression of NFIB represses Ezh2 transcription. Finally, key downstream targets of EZH2-mediated epigenetic repression are misregulated in Nfib(-/-) mice. Collectively, these results suggest that the downregulation of Ezh2 transcription by NFIB is an important component of the process of neural progenitor cell differentiation during cortical development.


Assuntos
Córtex Cerebral/crescimento & desenvolvimento , Epigênese Genética/fisiologia , Fatores de Transcrição NFI/genética , Fatores de Transcrição NFI/fisiologia , Complexo Repressor Polycomb 2/genética , Complexo Repressor Polycomb 2/fisiologia , Animais , Contagem de Células , Córtex Cerebral/citologia , Córtex Cerebral/fisiologia , Ensaio de Desvio de Mobilidade Eletroforética , Proteína Potenciadora do Homólogo 2 de Zeste , Feminino , Hipocampo/citologia , Hipocampo/crescimento & desenvolvimento , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Knockout , Análise em Microsséries , Mutação/genética , Mutação/fisiologia , Células-Tronco Neurais/fisiologia , Cultura Primária de Células , Regiões Promotoras Genéticas/genética , Reação em Cadeia da Polimerase em Tempo Real
10.
Mol Imaging ; 14: 385-99, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26218510

RESUMO

Noninvasive imaging is a critical technology for diagnosis, classification, and subsequent treatment planning for patients with glioblastoma. It has been shown that the EphA2 receptor tyrosine kinase (RTK) is overexpressed in a number of tumors, including glioblastoma. Expression levels of Eph RTKs have been linked to tumor progression, metastatic spread, and poor patient prognosis. As EphA2 is expressed at low levels in normal neural tissues, this protein represents an attractive imaging target for delineation of tumor infiltration, providing an improved platform for image-guided therapy. In this study, EphA2-4B3, a monoclonal antibody specific to human EphA2, was labeled with 64Cu through conjugation to the chelator 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA). The resulting complex was used as a positron emission tomography (PET) tracer for the acquisition of high-resolution longitudinal PET/magnetic resonance images. EphA2-4B3-NOTA-64Cu images were qualitatively and quantitatively compared to the current clinical standards of [18F]FDOPA and gadolinium (Gd) contrast-enhanced MRI. We show that EphA2-4B3-NOTA-64Cu effectively delineates tumor boundaries in three different mouse models of glioblastoma. Tumor to brain contrast is significantly higher in EphA2-4B3-NOTA-64Cu images than in [18F]FDOPA images and Gd contrast-enhanced MRI. Furthermore, we show that nonspecific uptake in the liver and spleen can be effectively blocked by a dose of nonspecific (isotype control) IgG.


Assuntos
Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Imageamento por Ressonância Magnética/métodos , Tomografia por Emissão de Pósitrons/métodos , Receptor EphA2/metabolismo , Animais , Anticorpos Monoclonais/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Meios de Contraste , Glioblastoma/patologia , Compostos Heterocíclicos/metabolismo , Compostos Heterocíclicos com 1 Anel , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Distribuição Tecidual , Ensaios Antitumorais Modelo de Xenoenxerto
11.
J Biol Chem ; 288(52): 37355-64, 2013 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-24265321

RESUMO

Studies in cell culture and mouse models of cancer have indicated that the soluble sphingolipid metabolite sphingosine 1-phosphate (S1P) promotes cancer cell proliferation, survival, invasiveness, and tumor angiogenesis. In contrast, its metabolic precursor ceramide is prodifferentiative and proapoptotic. To determine whether sphingolipid balance plays a significant role in glioma malignancy, we undertook a comprehensive analysis of sphingolipid metabolites in human glioma and normal gray matter tissue specimens. We demonstrate, for the first time, a systematic shift in sphingolipid metabolism favoring S1P over ceramide, which increases with increasing cancer grade. S1P content was, on average, 9-fold higher in glioblastoma tissues compared with normal gray matter, whereas the most abundant form of ceramide in the brain, C18 ceramide, was on average 5-fold lower. Increased S1P content in the tumors was significantly correlated with increased sphingosine kinase 1 (SPHK1) and decreased sphingosine phosphate phosphatase 2 (SGPP2) expression. Inhibition of S1P production by cultured glioblastoma cells, using a highly potent and selective SPHK1 inhibitor, blocked angiogenesis in cocultured endothelial cells without affecting VEGF secretion. Our findings validate the hypothesis that an altered ceramide/S1P balance is an important feature of human cancers and support the development of SPHK1 inhibitors as antiangiogenic agents for cancer therapy.


Assuntos
Neoplasias Encefálicas/metabolismo , Ceramidas/biossíntese , Glioblastoma/metabolismo , Metabolismo dos Lipídeos , Lisofosfolipídeos/biossíntese , Neovascularização Patológica/metabolismo , Esfingosina/análogos & derivados , Inibidores da Angiogênese/uso terapêutico , Animais , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Ceramidas/genética , Inibidores Enzimáticos/uso terapêutico , Seguimentos , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Lisofosfolipídeos/genética , Masculino , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/genética , Neovascularização Patológica/patologia , Monoéster Fosfórico Hidrolases/antagonistas & inibidores , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/antagonistas & inibidores , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Esfingosina/biossíntese , Esfingosina/genética , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
12.
Growth Factors ; 32(6): 254-64, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25410964

RESUMO

The Eph genes are the largest sub-family of receptor tyrosine kinases; however, it is most likely the least understood and the arena for many conflicting reports. In this tribute to Prof. Martin Lackmann and Prof. Tony Pawson, we utilized The Cancer Genome Atlas resources to shed new light on the understanding of this family. We found that mutation and expression analysis define two clusters of co-expressed Eph family genes that relate to aggressive phenotypes across multiple cancer types. Analysis of signal transduction pathways using reverse-phase protein arrays revealed a network of interactions, which associates cluster-specific Eph genes with epithelial-mesenchymal transition, metabolism, DNA-damage repair and apoptosis. Our findings support the role of the Eph family in modulating cancer progression and reveal distinct patterns of Eph expression, which correlate with disease outcome. These observations provide further rationale for seeking cancer therapies, which target the Eph/ephrin system.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias/diagnóstico , Receptores da Família Eph/metabolismo , Animais , Biomarcadores Tumorais/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias/genética , Neoplasias/metabolismo , Receptores da Família Eph/genética
13.
Tumour Biol ; 35(2): 1459-65, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24068568

RESUMO

Reduced levels of specific microRNA in cancer are frequently reported and associated with attenuated cancer genes and associated pathways. We previously reported a loss of miR-124a in glioblastoma (GBM) patient specimens; however, the upstream causes of this loss are largely unknown. Loss of miR-124a has been attributed to hypermethylation while other studies have shown miR-124a to be regulated by the repressor-element-1-silencing transcription factor (REST, also known as neuron-restrictive silencing factor). This current study looked at both epigenetic and transcription factor regulation as potential mechanisms resulting in the loss of miR-124a expression in GBM patient specimens and cell lines. Hypermethylation of miR-124a was observed in 82 % of GBM patient specimens (n = 56). In vitro miR-124a expression levels also increased after treatment of several patient-derived cell lines with 5-aza-2'-deoxycytidine. Additionally, we also demonstrated a positive interaction between REST activity and miR-124a using a luciferase-binding assay and we correlated the reciprocal expression of REST and miR-124a in our clinical cohort. This result indicates that miR-124a expression may also be modulated through the upstream targeting of REST. Preclinical studies involving inhibitors of REST and treatment with demethylating agents with the intent to increase miR-124a levels could be interesting.


Assuntos
Neoplasias Encefálicas/genética , Glioblastoma/genética , MicroRNAs/genética , Proteínas Repressoras/genética , Idoso , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células , Metilação de DNA/genética , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Inativação Gênica , Glioblastoma/patologia , Humanos , Pessoa de Meia-Idade
14.
Oncotarget ; 15: 1-18, 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38227740

RESUMO

Glioblastoma cells can restrict the DNA-damaging effects of temozolomide (TMZ) and radiation therapy (RT) using the DNA damage response (DDR) mechanism which activates cell cycle arrest and DNA repair pathways. Ataxia-telangiectasia and Rad3-Related protein (ATR) plays a pivotal role in the recognition of DNA damage induced by chemotherapy and radiation causing downstream DDR activation. Here, we investigated the activity of gartisertib, a potent ATR inhibitor, alone and in combination with TMZ and/or RT in 12 patient-derived glioblastoma cell lines. We showed that gartisertib alone potently reduced the cell viability of glioblastoma cell lines, where sensitivity was associated with the frequency of DDR mutations and higher expression of the G2 cell cycle pathway. ATR inhibition significantly enhanced cell death in combination with TMZ and RT and was shown to have higher synergy than TMZ+RT treatment. MGMT promoter unmethylated and TMZ+RT resistant glioblastoma cells were also more sensitive to gartisertib. Analysis of gene expression from gartisertib treated glioblastoma cells identified the upregulation of innate immune-related pathways. Overall, this study identifies ATR inhibition as a strategy to enhance the DNA-damaging ability of glioblastoma standard treatment, while providing preliminary evidence that ATR inhibition induces an innate immune gene signature that warrants further investigation.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Humanos , Temozolomida/farmacologia , Temozolomida/uso terapêutico , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/radioterapia , Dacarbazina/farmacologia , Dacarbazina/uso terapêutico , Antineoplásicos Alquilantes/farmacologia , Antineoplásicos Alquilantes/uso terapêutico , Proteínas Supressoras de Tumor/metabolismo , Morte Celular , Linhagem Celular , DNA , Linhagem Celular Tumoral , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismo , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/radioterapia , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo
15.
Methods Mol Biol ; 2765: 299-309, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38381346

RESUMO

Circular RNAs (circRNAs) are a widespread, cell-, tissue-, and disease-specific class of largely non-coding RNA transcripts. These single-stranded, covalently-closed transcripts arise through non-canonical splicing of pre-mRNA, a process called back-splicing. Back-splicing results in circRNAs which are distinguishable from their cognate mRNA as they possess a unique sequence of nucleic acids called the backsplice junction (BSJ). CircRNAs have been shown to play key functional roles in various cellular contexts and achieve this through their interaction with other macromolecules, particularly other RNA molecules and proteins. To elucidate the molecular mechanisms underlying circRNA function, it is necessary to identify these interacting partners. Herein, we present an optimized strategy for the simultaneous purification of the circRNA interactome within eukaryotic cells, allowing the identification of both circRNA-RNA and circRNA-protein interactions.

16.
Trends Cancer ; 9(3): 223-236, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36460606

RESUMO

Glioblastoma (GBM) remains the most lethal primary brain cancer largely due to recurrence of treatment-resistant disease. Current therapies are ultimately ineffective as GBM tumour cells adapt their identity to escape treatment. Recent advances in single-cell epigenetics and transcriptomics highlight heterogeneous cell populations in GBM tumours originating from unique cancerous genetic aberrations. However, they also suggest that tumour cells conserve molecular properties of parent neuronal cells, with their permissive epigenetic profiles enabling them to morph along a finite number of reprogramming routes to evade treatment. Here, we review the known tumourigenic, neurodevelopmental and brain-injury boundaries of GBM plasticity, and propose that effective treatment of GBM requires the addition of therapeutics that restrain GBM plasticity.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Humanos , Neoplasias Encefálicas/genética , Glioblastoma/genética , Carcinogênese/genética , Transformação Celular Neoplásica/genética , Epigênese Genética
17.
Cells ; 12(2)2023 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-36672257

RESUMO

The existence of circular RNA (circRNA) research in mainstream science can be attributed to the contemporary synergism of big data and keen attention to detail by several research groups worldwide. Since the re-emergence of these non-canonical RNA transcripts, seminal advances have been made in understanding their biogenesis, interactome, and functions in diverse fields and a myriad of human diseases. However, most research outputs to date have focused on the ability of highly stable circRNAs to interact with, and impact signalling through, microRNAs. This is likely to be the result of seminal papers in the field ascribing a few remarkable circRNAs as "miRNA sponges". However, the stoichiometric ratio between the (often-lowly-expressed) circRNA and their (commonly-more-abundant) target is rarely in favour of a biologically relevant and functional consequence of these interactions. It is time for yet another revolution in circRNA research to uncover functions beyond their documented ability to bind miRNAs. This Special Issue aims to highlight non-canonical functions for this non-canonical family of RNA molecules.


Assuntos
MicroRNAs , RNA Circular , Humanos , RNA Circular/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Transdução de Sinais
18.
bioRxiv ; 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-38045421

RESUMO

Circular RNAs (circRNAs) are a class of single-stranded, covalently closed RNA that contain a unique back-splice junction (bsj) sequence created by the ligation of their 5' and 3' ends via spliceosome-catalyzed back-splicing. A key step in illuminating the cellular roles of specific circRNAs is via increasing their expression. This is frequently done by transfecting cells with plasmid DNA containing cloned exons from which the circRNA is transcribed, flanked by sequences that promote back-splicing. We observed that commonly used plasmids lead to the production of circRNAs with molecular scars at the circRNA bsj. Stepwise redesign of the cloning vector corrected this problem, ensuring bona fide circRNAs are produced with their natural bsj at high efficiency. The fidelity of circRNAs produced from this new construct was validated by RNA sequencing and also functionally validated. To increase the utility of this modified resource for expressing circRNA, we developed an expanded set of vectors incorporating this design that (i) enables selection with a variety of antibiotics and fluorescent proteins, (ii) employs a range of promoters varying in promoter strength and (iii) generated a complementary set of lentiviral plasmids for difficult-to-transfect cells. These resources provide a novel and versatile toolkit for high-efficiency and scarless overexpression of circular RNAs that fulfill a critical need for the investigation of circRNA function.

19.
Cells ; 12(9)2023 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-37174737

RESUMO

Trinucleotide repeat disorders comprise ~20 severe, inherited, human neuromuscular and neurodegenerative disorders, which result from an abnormal expansion of repetitive sequences in the DNA. The most common of these, Huntington's disease (HD), results from expansion of the CAG repeat region in exon 1 of the HTT gene via an unknown mechanism. Since non-coding RNAs have been implicated in the initiation and progression of many diseases, herein we focused on a circular RNA (circRNA) molecule arising from non-canonical splicing (backsplicing) of HTT pre-mRNA. The most abundant circRNA from HTT, circHTT(2-6), was found to be more highly expressed in the frontal cortex of HD patients, compared with healthy controls, and positively correlated with CAG repeat tract length. Furthermore, the mouse orthologue (mmu_circHTT(2-6)) was found to be enriched within the brain and specifically the striatum, a region enriched for medium spiny neurons that are preferentially lost in HD. Transgenic overexpression of circHTT(2-6) in two human cell lines-SH-SY5Y and HEK293-reduced cell proliferation and nuclear size without affecting cell cycle progression or cellular size, or altering the CAG repeat region length within HTT. CircHTT(2-6) overexpression did not alter total HTT protein levels, but reduced its nuclear localisation. As these phenotypic and genotypic changes resemble those observed in HD patients, our results suggest that circHTT(2-6) may play a functional role in the pathophysiology of this disease.


Assuntos
Doença de Huntington , Neuroblastoma , Humanos , Camundongos , Animais , Doença de Huntington/metabolismo , RNA Circular/genética , Células HEK293 , Animais Geneticamente Modificados
20.
Cancers (Basel) ; 15(21)2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-37958423

RESUMO

Glioblastoma is the most common primary brain cancer in adults and represents one of the worst cancer diagnoses for patients. Suffering from a poor prognosis and limited treatment options, tumor recurrences are virtually inevitable. Additionally, treatment resistance is very common for this disease and worsens the prognosis. These and other factors are hypothesized to be largely due to the fact that glioblastoma cells are known to be able to obtain stem-like traits, thereby driving these phenotypes. Recently, we have shown that the in vitro and ex vivo treatment of glioblastoma stem-like cells with the hormonally active form of vitamin D3, calcitriol (1α,25(OH)2-vitamin D3) can block stemness in a subset of cell lines and reduce tumor growth. Here, we expanded our cell panel to over 40 different cultures and can show that, while half of the tested cell lines are sensitive, a quarter can be classified as high responders. Using genetic and proteomic analysis, we further determined that treatment success can be partially explained by specific polymorphism of the vitamin D3 receptor and that high responders display a proteome suggestive of blockade of stemness, as well as migratory potential.

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