RESUMO
The formation, overgrowth and metastasis of tumors comprise a complex series of cellular and molecular events resulting from the combined effects of a variety of aberrant signaling pathways, mutations, and epigenetic alterations. Modeling this complexity in vivo requires multiple genes to be manipulated simultaneously, which is technically challenging. Here, we analyze how Drosophila research can further contribute to identifying pathways and elucidating mechanisms underlying novel cancer driver (risk) genes associated with tumor growth and metastasis in humans.
Assuntos
Drosophila , Neoplasias , Oncogenes , Animais , Modelos Animais de Doenças , Humanos , Mutação , Transdução de SinaisRESUMO
When Mary Stark first described the presence of tumours in the fruit fly Drosophila melanogaster in 1918, would she ever have imagined that flies would become an invaluable organism for modelling and understanding oncogenesis? And if so, would she have expected it to take 100 years for this model to be fully accredited? This Special Article summarises the efforts and achievements of Drosophilists to establish the fly as a valid model in cancer research through different scientific periods.
Assuntos
Pesquisa Biomédica/história , Drosophila melanogaster/fisiologia , Neoplasias/história , Animais , Avaliação Pré-Clínica de Medicamentos , Genes Supressores de Tumor , História do Século XX , História do Século XXI , Neoplasias/genética , OncogenesRESUMO
The PI3K/Akt signaling pathway, Notch, and other oncogenes cooperate in the induction of aggressive cancers. Elucidating how the PI3K/Akt pathway facilitates tumorigenesis by other oncogenes may offer opportunities to develop drugs with fewer side effects than those currently available. Here, using an unbiased in vivo chemical genetic screen in Drosophila, we identified compounds that inhibit the activity of proinflammatory enzymes nitric oxide synthase (NOS) and lipoxygenase (LOX) as selective suppressors of Notch-PI3K/Akt cooperative oncogenesis. Tumor silencing of NOS and LOX signaling mirrored the antitumor effect of the hit compounds, demonstrating their participation in Notch-PI3K/Akt-induced tumorigenesis. Oncogenic PI3K/Akt signaling triggered inflammation and immunosuppression via aberrant NOS expression. Accordingly, activated Notch tumorigenesis was fueled by hampering the immune response or by NOS overexpression to mimic a protumorigenic environment. Our lead compound, the LOX inhibitor BW B70C, also selectively killed human leukemic cells by dampening the NOTCH1-PI3K/AKT-eNOS axis.
Assuntos
Drosophila melanogaster/metabolismo , Inflamação/patologia , Óxido Nítrico/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores Notch/metabolismo , Animais , Carcinogênese/metabolismo , Catecol Oxidase/metabolismo , Linhagem Celular Tumoral , Avaliação Pré-Clínica de Medicamentos , Precursores Enzimáticos/metabolismo , Marcação de Genes , Hemócitos/metabolismo , Humanos , Terapia de Imunossupressão , Inflamação/imunologia , Lipoxigenases/metabolismo , Óxido Nítrico Sintase/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Interferência de RNA , Reprodutibilidade dos Testes , Transdução de SinaisRESUMO
Anterior definitive endoderm (ADE), the ventral foregut precursor, is both an important embryonic signaling center and a unique multipotent precursor of liver, pancreas, and other organs. Here, a method is described for the differentiation of mouse embryonic stem cells (mESCs) to definitive endoderm with pronounced anterior character. ADE-containing cultures can be produced in vitro by suspension (embryoid body) culture or in a serum-free adherent monolayer culture. ESC-derived ADE cells are committed to endodermal fates and can undergo further differentiation in vitro towards ventral foregut derivatives.
Assuntos
Diferenciação Celular/fisiologia , Embrião de Mamíferos , Endoderma , Intestinos , Células-Tronco Embrionárias Murinas , Animais , Técnicas de Cultura de Células , Células Cultivadas , Embrião de Mamíferos/citologia , Embrião de Mamíferos/embriologia , Endoderma/citologia , Endoderma/embriologia , Humanos , Intestinos/embriologia , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismoRESUMO
The fibroblast growth factor (FGF) signalling pathway is one of the most ubiquitous in biology. It has diverse roles in development, differentiation and cancer. Embryonic stem (ES) cells are in vitro cell lines capable of differentiating into all the lineages of the conceptus. As such they have the capacity to differentiate into derivatives of all three germ layers and to some extent the extra-embryonic lineages as well. Given the prominent role of FGF signalling in early embryonic development, we explore the role of this pathway in early ES cell differentiation towards the major lineages of the embryo. As early embryonic differentiation is intricately choreographed at the level of morphogenetic movement, adherent ES cell culture affords a unique opportunity to study the basic steps in early lineage specification in the absence of ever shifting complex in vivo microenvironments. Thus recent experiments in ES cell differentiation are able to pinpoint specific FGF dependent lineage transitions that are difficult to resolve in vivo. Here we review the role of FGF signalling in early development alongside the ES cell data and suggest that FGF dependent signalling via phospho-Erk activation maybe a major mediator of transitions in lineage specification.
Assuntos
Diferenciação Celular , Linhagem da Célula , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Transdução de Sinais , Animais , Humanos , Receptores de Fatores de Crescimento de Fibroblastos/metabolismoRESUMO
Anterior definitive endoderm (ADE) is both an important embryonic signaling center and a unique multipotent precursor of liver, pancreas, and other visceral organs. Here we describe a method for the differentiation of mouse embryonic stem (ES) cells to endoderm with pronounced anterior character. ADE-containing cultures can be produced in vitro by suspension (aggregation or embryoid body) culture and in a serum-free adherent monolayer culture. Purified ES cell-derived ADE cells appear committed to endodermal fates and can undergo further differentiation in vitro towards liver and pancreas with enhanced efficiency.
Assuntos
Técnicas de Cultura de Células/métodos , Diferenciação Celular , Células-Tronco Embrionárias/citologia , Endoderma/citologia , Animais , Adesão Celular , Agregação Celular , Embrião de Mamíferos/citologia , CamundongosRESUMO
We investigated the neuroprotective effect of glial-derived neurotrophic factor (GDNF) upon alcohol-exposed B92 cultures, as well as the role of the cytoskeleton and mitogen-activated protein kinase (MAPK) pathways in this effect. Ethanol (EtOH) was added to cultures, either alone or in combination with 30 ng/ml GDNF. Exposure to EtOH (86 and 172 mM; 60 and 120 min) increased the frequency of apoptotic cells identified by nuclear DNA staining with 4,6-diamidino-2-phenylindole (DAPI). Cultures treated with GDNF showed a decrease in ethanol-induced apoptosis. A jun N-terminal kinase (JNK) pathway is activated by EtOH and their pharmacological inhibition (by SP600125) neutralized ethanol-induced apoptosis, suggesting a role for JNK in EtOH neurotoxicity. Immunocytochemically detected phospho-JNK (p-JNK) showed an unusual filamental expression, and localized together with actin stress fibers. Examination of the cytoskeleton showed that EtOH depolymerized actin filaments, inducing p-JNK dissociation and translocation to the nucleus, which suggests that released p-JNK may contribute to glial cell death after EtOH exposure. Treatment with GDNF, in turn, may neutralize the ethanol-induced cell death pathway. Either a phosphatidylinositol 3-kinase (PI3K)/AKT pathway inhibitor (LY294002) or an inhibitor of the extracellular signal-regulated kinase (ERK) 1, 2 pathways (UO126) failed to neutralize GDNF protective effects. However, the simultaneous use of both inhibitors blocked the protective effect of GDNF, suggesting a role for both signaling cascades in the GDNF protection. These findings provide further insight into the mechanism involved in ethanol-induced apoptosis and the neurotrophic protection of glial cells.
Assuntos
Apoptose/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Etanol/antagonistas & inibidores , Fator Neurotrófico Derivado de Linhagem de Célula Glial/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Neuroglia/efeitos dos fármacos , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/metabolismo , Transtornos do Sistema Nervoso Induzidos por Álcool/tratamento farmacológico , Transtornos do Sistema Nervoso Induzidos por Álcool/metabolismo , Transtornos do Sistema Nervoso Induzidos por Álcool/fisiopatologia , Animais , Apoptose/fisiologia , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Linhagem Celular Tumoral , Depressores do Sistema Nervoso Central/antagonistas & inibidores , Depressores do Sistema Nervoso Central/toxicidade , Citoproteção/efeitos dos fármacos , Citoproteção/fisiologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Etanol/toxicidade , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , MAP Quinase Quinase 1/antagonistas & inibidores , MAP Quinase Quinase 1/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Neuroglia/metabolismo , Fármacos Neuroprotetores/metabolismo , Fármacos Neuroprotetores/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , RatosRESUMO
Several studies on neurobiology have contributed to our understanding of the genesis, survival and death of neurons, unquestionably the stars of the Central Nervous System (CNS). However, they would not be so famous without their close associates: the glial cells. Since novel studies have demonstrated new and important functions for glial cells, they are beginning to gain significant importance in brain research to allow us to reinterpret long known functions on the basis of new concepts. Here, we review recent progress in our understanding of the role of glial cells in the biology of tissue development and maturation.