Thesis (M.Sc.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 92-106. Also available online.

Orientador: José Buratini Júnior / Banca: Paula de Carvalho Papa / Banca: João Carlos Pinheiro Ferreira / Resumo: A compreensão dos mecanismos moleculares controladores do desenvolvimento, função e regressão do CL bovino é necessária para o aprimoramento da manipulação hormonal ovariana. Fortes evidências sugerem o envolvimento de fatores de crescimento fibroblástico (FGFs) na regulação do crescimento e regressão do CL. "Splicing" alternativo de 4 genes formam sete subtipos de FGFRs com afinidade variável por diferentes FGFs. Os membros da subfamília do FGF8 (FGF8, 17 e 18) ativam eficientemente o FGFR3C e 4 e podem atuar em cooperação nos tecidos que expressão estes receptores. O objetivo deste trabalho foi determinar o padrão de expressão dos FGFRs e dos membros da subfamília do FGF8 no CL bovino (CL). Os CLs foram obtidos de ovários de abatedouro e classificados em 4 estádios de desenvolvimento (estádio/1= corpo hemorrágico, estádio/2= CL em desenvolvimento, estádio/3= CL maduro/início da luteólise funcional e estádio/4= luteólise estrutural). O RNAm foi mensurado por PCR semiquantitativo e a proteína localizada por imunohistoquímica. A expressão do RNAm codificante das isoformas 'B' e 'C' de FGFR1 e FGFR2 foi detectada no CL bovino por PCR associado à eletroforese e foi acompanhada pela localização da proteína nas pequenas e grandes células luteínicas. A expressão do RNAm do FGFR1C e 2C não variou durante o desenvolvimento luteínico, distintamente a expressão do FGFR1B aumentou no estádio 3. Embora os FGFRs 3B, 3C e 4 tenham sido detectados de forma inconsistente por PCR associado à eletroforese, o RNAm do FGFR3C e FGFR4 foram detectados por PCR em tempo real em todos os estádios do desenvolvimento luteínico. O RNAm do FGF18 foi detectado por PCR em tempo real em todos os estádios do desenvolvimento luteínico e sua abundancia do RNAm do FGF18 foi maior no estádio 3 comparado com os estádios 1, 2 e 4. Em contraste, os RNAm do FGF8 e 17 ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The molecular mechanisms controlling the development, function and regression of the bovine corpus luteum are necessary for the improvement of reproductive biotechnologies. Strong evidence suggests the involvement of fibroblast growth factors (FGFs) in the regulation of growth, and regression of the corpus luteum (CL). Alternative splicing of 4 genes give rise to seven subtypes of FGFRs with varying affinity for different FGFs. FGF8 subfamily members (FGF8, 17 and 18) efficiently activate FGFR3C and FGFR4 and may act in cooperation in tissues expressing these receptors. The objective of the present study was to determine the pattern of expression of FGF8 subfamily members and FGFRs in the bovine CL. Bovine CLs were obtained from abattoir ovaries and classed into four stages of development (stage 1= corpus hemorragicum, stage 2= developing CL, stage 3= mature/early functional luteolysis CL, and stage 4= structural luteolysis). Expression of mRNA was measured by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) followed by gel analysis (FGFR1-4) and real time RT-PCR (FGF8 subfamily members, FGFR3C and FGFR4) and proteins were localized by immunohistochemistry. Expression of mRNA encoding 'B' and 'C' spliced forms of FGFR1 and FGFR2 was readily detected in the bovine CL and was accompanied by isoform non-specific protein localization. FGFR1C and FGFR2C mRNA expression did not vary throughout CL lifespan, whereas FGFR1B was upregulated in the mature CL (stage III). FGFR3B, FGFR3C and FGFR4 expression was inconsistent in the bovine CL as assessed by PCR associated with gel analysis. FGF18, FGFR3C and FGFR4 mRNA was detected by real time PCR in all four developmental stages, and FGF18 mRNA abundance was higher in stage 3 (2.89  0.05; mean ± SEM) compared with stages 1 (0.3  0.27), 2 (0.56  1.27) and 4 (0.99  0.32). The m RNA expression ... (Complete abstract click electronic access below) / Mestre

Orientadores: Lília Freire Rodrigues de Souza Li, Marcelo Ananias Teocchi / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T06:18:40Z (GMT). No. of bitstreams: 1 Ferreira_AnaErikaDias_M.pdf: 2703005 bytes, checksum: 3e71e1e36f3b90f6651557533137b593 (MD5) Previous issue date: 2014 / Resumo: Epilepsia do lobo temporal (ELT) é a forma mais comum de epilepsia em adultos. O processo de epileptogênese inclui a morte neuronal, brotamento axonal, inflamação, neurogênese, estresse oxidativo e gliose. No entanto, os mecanismos moleculares subjacentes não são totalmente compreendidos. Os fatores de crescimento de fibroblastos (FGFs) são uma família de proteínas com várias funções no organismo, especialmente no sistema nervoso central. No entanto, o funcionamento dos FGFs no cérebro humano não é totalmente compreendido. O FGF2 é o membro mais estudado dessa família e seu papel na fisiopatologia da epilepsia é controversa. Na tentativa de esclarecer o envolvimento da via de FGF na ELT, nós quantificamos a expressão hipocampal dos seguintes genes: FGF2, FGF8, FGF22, FGFR1, FGFR2, FGFR3, ITPR3, PIK3R3 e PIK3R5 em 10 pacientes resistentes a fármacos e quatro controles post mortem. Além disso, avaliamos a expressão da proteína de FGF2 por imunofluorescência indireta. Apenas para o FGF2, houve aumento do RNAm no hipocampo dos pacientes para os dois genes de referência testados, HPRT1 e ENO2 + TBP em combinação (P = 0,002 e P = 0,036; respectivamente). A porcentagem de células imunomarcadas para FGF2 no giro dentado foi maior nos pacientes do que nos controles (P <0,05), mas nenhuma alteração significativa foi encontrada no Corno de Ammon. O FGF2 pode preservar os neurônios após lesão e atua como um poderoso fator para a proliferação de células-tronco neurais. Assim, o FGF2 poderia aliviar os danos induzidos pelas crises, intensificar a reparação e reduzir a epileptogênese no hipocampo. Por outro lado, evidências têm demonstrado o envolvimento do FGF2 em mecanismos epileptogênicos, como brotamento de fibras musgosas e neurogênese. Nossos resultados sugerem a participação do FGF2 na fisiopatologia da ELT e o indica como um importante alvo para estudos farmacológicos / Abstract: Temporal lobe epilepsy (TLE) is the most common form of epilepsy in adults. The process of epileptogenesis includes neuronal death, axonal sprouting, inflammation, neurogenesis, oxidative stress and gliosis. However, the molecular mechanisms behind them are not fully understood. Fibroblast growth factor (FGF) gene family encodes proteins with several functions in the organism, especially in the central nervous system. FGF family member functions in the human brain are unclear. To shed light on the involvement of the FGF pathway in TLE, we quantified the hippocampal expression of the following genes: FGF2, FGF8, FGF22, FGFR1, FGFR2, FGFR3, ITPR3, PIK3R3 and PIK3R5 in 10 pharmacoresistant patients and four post mortem controls. We also assessed the FGF2 protein expression by indirect immunofluorescence. Only for FGF2, was the mRNA level markedly increased in patients¿ hippocampi for the two reference genes tested, HPRT1 and ENO2+TBP in combination (P = 0.002 and P = 0.036, respectively). The percentage of FGF2 immunostained cells in the dentate gyrus was higher in patients than in the controls (P <0.05), but no significant alteration was found in the Ammon¿s horn. FGF2 preserves neurons from ongoing injury and acts as a powerful proliferation factor for neural stem cells. It could potentially alleviate seizure-induced damage and intensify repair and reduce epileptogenesis in the hippocampus. On the other hand, evidence has shown FGF2¿s involvement in epileptogenic mechanisms, such as axonal sprouting and neurogenesis. Our results clearly suggest the FGF2 participation in TLE physiopathology and point it out as an important target for pharmacological studies / Mestrado / Saude da Criança e do Adolescente / Mestra em Ciências

Orientador: Valeria Helena Alves Cagnon Quitete / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-22T09:05:18Z (GMT). No. of bitstreams: 1 Hetzl_AmandaCia_D.pdf: 39910159 bytes, checksum: 9f69d8623d48f1fccdc9aebc181573a3 (MD5) Previous issue date: 2013 / Resumo: A senescência é fator determinante para a ocorrência de alterações morfofuncionais da próstata. O objetivo desse estudo foi caracterizar e correlacionar as interações entre os receptores dos fatores de crescimento fibroblásticos (FGFR2, FGFR7, FGFR8), fator de crescimento epidermal (EGFR), ?-actina e vimentina e os receptores androgênicos (AR), estrogênicos ? e ? (ER?, ER?) e de prolactina (PR) nos compartimentos epiteliais e estromal frente à condição de senilidade e variações hormonais. Além disso, caracterizar e correlacionar o AR, ER?, ER? e PR com os FGFs nos compartimentos epitelial e estromal de amostras humanas com adenocarcinoma de alto grau e baixo grau. 50 ratos machos senis (10 meses de idade) e 10 ratos machos jovens (4 meses de idade) foram divididos em grupos: Jovem (JOV) e Senil (SE): óleo de amendoim por 30 dias; Castrado (CAS): castração cirúrgica e química; Tamoxifeno-Letrozol (TAM): tamoxifeno e de letrozol por 30 dias; Castrado+estrógeno (REEST): tratamento similar ao CAS, e posteriormente recebeu injeções de 17?-estradiol por 30 dias; Tamoxifeno-Letrozol+Andrógeno (RETEST): após tratamento similar ao grupo TAM, os animais receberam injeções de Cipionato de Testosterona por 30 dias. Os animais foram sacrificados e amostras do lobo ventral foram coletadas e submetidas às análises de Microscopia de Luz, imunohistoquímicas, western blotting e dosagem hormonal. 30 amostras prostáticas humanas foram divididas em grupos: Adenocarcinoma de alto grau e Adenocarcinoma de baixo grau. As amostras foram submetidas às análises de Microscopia de luz e imunohistoquímicas. Após a administração estrogênica, presença de microácinos, células inflamatórias e hipertrofia do estroma prostático foram observados. A hiperandrogenização levou à recuperação epitelial. No SE houve aumento de vimentina, ER? e PR em relação ao JOV. No CAS observou-se localização diferencial da prolactina e ?-actina em relação ao SE. No RETEST, observou-se recuperação do padrão de distribuição de reatividade da ?-actina e da prolactina em relação ao SE. No REEST foi observado aumento de ER? e ER? e localização diferencial destes, somando-se a diminuição da ?-actina e vimentina em relação ao SE. No TAM foi observada diminuição de ER? e ?-actina, e aumento de prolactina no compartimento estromal, em relação ao SE. Em humanos, os FGFR2 e FGFR8 apresentaram-se aumentados no estágio inicial do câncer prostático, sugerindo essas moléculas como bons alvos terapêuticos. Pode-se concluir que o envolvimento do ER? na ativação do estroma reativo tornou o microambiente favorável à progressão do câncer, devido à potencialização do desequilíbrio estromal, e o ER? contribuíram para a inibição das lesões précancerosas em homens na senescência. Já, o desequilíbrio causado pela ablação e/ou reposição hormonal não somente alterou o feedback entre os hormônios esteróides como modificou a localização da reatividade das moléculas nos compartimentos prostáticos, provavelmente interferindo nas sinalizações autócrinas e parácrinas dos estrógenos, EGF e prolactina, apontando esses como deflagradores da formação do estroma reativo. A ablação hormonal nos animais senis levou ao aumento da reatividade dos FGFs, sugerindo interações entre os hormônios e suas vias de sinalização e o microambiente prostático senil. As vias dos FGFs podem ser ativadas também de maneira andrógeno-independente, uma vez que os FGFs apresentaram níveis de detecção aumentados mesmo diante da intensa depleção androgênica imposta pela castração / Abstract: Senescence is a determining factor for morphological and functional prostatic alterations. The objective of this study was to characterize and correlate the interactions among fibroblast growth factor receptors (FGFR2, FGFR7, FGFR8), epidermal growth factor (EGFR), ?-actin and vimentin and the androgen receptor (AR), estrogen ? and ? (ER?, ER?) and prolactin (PR) in epithelial and stromal prostatic compartments in elderly rats on hormonal variation. Also, the objective was to characterize and correlate the AR, ER?, ER? and PR with the FGFs in the human prostatic samples, presenting high grade and low grade adenocarcinoma. Fifty male rats (10 months old) and 10 young male rats (4 months old) were divided into groups: Young (JOV) and Senile Groups (SE)- peanut oil injections for 30 days, Castrated Group (CAS)- surgical and chemical castration; Tamoxifen-Letrozole Group (TAM)- tamoxifen and letrozole injections in period of 48 hours for 30 days; Castrated + estrogen Group (REEST)- surgical and chemical castration and subsequently the animals received 17?-estradiol injections for 30 days; Tamoxifen- Letrozole + Androgen Group (RETEST): after treatment similar to the TAM group, the animals received testosterone cypionate injections for 30 days. After the treatment, the animals were sacrificed and the ventral lobe samples were collected and analyzed for the Light Microscopy, immunohistochemistry and Western blotting. Thirty human prostatic samples were collected from elderly men and divided into High-grade and Low-grade Adenocarcinoma Groups. The samples were submitted to light microscopy and immunohistochemical analyses. After estrogen administration, epithelial atrophy, microacini, inflammatory cells and stromal hypertrophy were observed. The hyperandrogenization led to the recovery of epithelium. The vimentin, ER? and PR increase was verified in the SE group in relation to JOV one. Differential localization of PR and ?-actin was seen in the CAS group in relation to SE one. Recovery of the distribution pattern of ?-actin and prolactin reactivities was observed in the RETEST group in relation to SE. In the REEST group, it was observed the ER? and ER? increase and differential localization of these receptors, and the ?-actin and vimentin decrease in relation to SE. In the group TAM, it was observed the ER? and ?-actin decrease and the prolactin increase in the stromal compartment in relation to SE group. Regarding to human samples, increased FGFR2 and FGFR8 were observed in the early stages of prostate cancer, suggesting these molecules as good therapeutic targets. Thus, it can be concluded that the involvement of ER? in activation of reactive stromal led to the favorable microenvironment to cancer progression considering the strong stromal imbalance, and the ER? contributed to the inhibition of precancerous lesions in elderly men. The imbalance caused by ablation and/or hormone therapy not only changed the feedback between steroid hormones but also changed the reactivity localization of molecules in prostatic compartments, probably interfering in the autocrine and paracrine signaling of estrogen, prolactin and EGF, and pointing these molecules as possible triggers of the formation of reactive stroma. The present results demonstrated that hormone ablation in senile rats led to increased reactivities of the FGFs, suggesting interactions among hormones and their signaling pathways and senile prostatic microenvironment. Furthermore, it can be concluded that the ways of FGFs can be activated also androgen-independent manner, considering that the FGFs showed increased levels in the severe androgen depletion characterized by castration / Doutorado / Anatomia / Doutora em Biologia Celular e Estrutural

Fibroblast growth factor (Fgf) signaling plays multiple inductive roles during development of vertebrates (Itoh 2007). Some Fgfs, such as Fgf8, are locally secreted and signal over a long range to provide positional information in the target tissue (Scholpp and Brand 2004). Fgf ligands signal in a receptor-dependent manner via tyrosine kinase receptors, four of which have been so far identified. Fgf8 signaling was shown to depend both on receptor activation as well as endocytosis. The specificity of Fgf ligands and receptors as well as the function of receptors in the control of the Fgf signaling range have been, however, largely unclear. In this study, we show that the putative Fgf8 receptor Fgfr1 is duplicated in zebrafish and that it acts redundantly in the formation of the posterior mesoderm. Also, in overexpression studies we confirm the notion that receptor endocytosis influences Fgf8 signaling range. Through TILLING mutant recovery and morpholino knockdown studies we also show that Fgfr2 is required for growth and skeletal development in zebrafish, whereas Fgfr4 is required for pectoral fin specification and growth.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 100-117).

Les « Facteurs de croissance des fibroblastes» (FGF) agissent comme des régulateurs locaux sur la qualité des follicules et sont connus pour promouvoir la prolifération des cellules de granulosa, réduire l’apoptose et la stéroïdogenèse. Parmi la sous-famille FGF8, FGF18 est une exception puisqu’il semblerait avoir une fonction pro-apoptotique alors que FGF8 n’a pas été jusqu’à présent rapporté comme altérant la viabilité des cellules de la granulosa. Ces deux ligands ont un mode d’activation similaire et il pourrait être proposé que toute la sous-famille FGF8 ait la même réponse. L’objectif de cette étude était de déterminer si FGF8 et FGF18 activaient la même réponse précoce de gènes dans des cultures de granulosa bovine. Pour répondre à cette question, nous avons cultivé des cellules de la granulosa dans du milieu de culture sans sérum pendant 5 jours. Le jour 5, les cellules ont été traitées avec FGF8 ou FGF18. Nous avons eu recours à une approche de « puce à ADN » afin d’identifier la réponse précoce de gènes induite par FGF8 et FGF18, et les données ont été confirmées par des PCRs en temps réel lors d’une expérience in vitro où les cellules de granulosa ont été traitées avec FGF8 et FGF18 pendant différents temps. L’analyse du puce à ADN a identifié 12 gènes surexprimés par FGF8, incluant SPRY2, NR4A1, XIRP1, BAMBI, EGR1, FOS et FOSL1. A l’inverse, FGF18 n’a régulé aucun gène de manière significative. Les analyses de PCR ont confirmé l’augmentation d’ARNm codant pour EGR1, EGR3, FOS, XIRP1, FOSL1, SPRY2, NR4A1 et BAMBI après 2 h de traitement. FGF18 a entrainé seulement une augmentation de l’expression de EGR1 après 2 h de traitement parmi tous les gènes testés. Ces résultats démontrent donc que FGF8 et FGF18, malgré leur similarité dans le mode d’activation de leurs récepteurs, agissent sur les cellules de la granulosa via différentes voies de signalisation. FGF8 et FGF18, sont donc tous les deux capables de stimuler l’expression de EGR1, mais les voies de signalisation induites par la suite divergent. / Fibroblast growth factors (FGF) act as local regulators of follicular health and are known to increase granulosa cell (GC) proliferation, reduce apoptosis and decrease steroidogenesis. One exception is FGF18, which appears to be a pro apoptotic member of the FGF8-subfamily while FGF8 has not been reported to alter GC health. These two ligands have similar activation patterns and it could be proposed that all FGF8-subfamilies would have the same response. The objective of this study was to determine if FGF8 and FGF18 activate the same early response genes in cultured bovine GC. To address this we cultured GC in serum free medium for five days. On day 5, cells were challenged with FGF8 or FGF18. We used a microarray approach to identify early response genes altered by FGF8 and FGF18, and data were confirmed by real-time PCR in an independent time-course experiment. Microarray identified 12 genes up-regulated by FGF8, including SPRY2, NR4A1, XIRP1, BAMBI, EGR1, FOS and FOSL1. In contrast FGF18 did not result in significant regulation of any gene. PCR analysis confirmed the stimulation of abundance of mRNA encoding EGR1, EGR3, FOS, XIRP1, FOSL1, SPRY2, NR4A1 and BAMBI after 2 hours of challenge. FGF18 resulted in an increase of EGR1 mRNA abundance at 2 h, but not of the other genes tested. These results demonstrate that FGF8 and FGF18, despite reportedly similar receptor activation patterns, act on granulosa cells through different intracellular pathways. Both FGF8 and FGF18 stimulate EGR1 expression, but thereafter their signaling pathways diverge.

Les « Facteurs de croissance des fibroblastes» (FGF) agissent comme des régulateurs locaux sur la qualité des follicules et sont connus pour promouvoir la prolifération des cellules de granulosa, réduire l’apoptose et la stéroïdogenèse. Parmi la sous-famille FGF8, FGF18 est une exception puisqu’il semblerait avoir une fonction pro-apoptotique alors que FGF8 n’a pas été jusqu’à présent rapporté comme altérant la viabilité des cellules de la granulosa. Ces deux ligands ont un mode d’activation similaire et il pourrait être proposé que toute la sous-famille FGF8 ait la même réponse. L’objectif de cette étude était de déterminer si FGF8 et FGF18 activaient la même réponse précoce de gènes dans des cultures de granulosa bovine. Pour répondre à cette question, nous avons cultivé des cellules de la granulosa dans du milieu de culture sans sérum pendant 5 jours. Le jour 5, les cellules ont été traitées avec FGF8 ou FGF18. Nous avons eu recours à une approche de « puce à ADN » afin d’identifier la réponse précoce de gènes induite par FGF8 et FGF18, et les données ont été confirmées par des PCRs en temps réel lors d’une expérience in vitro où les cellules de granulosa ont été traitées avec FGF8 et FGF18 pendant différents temps. L’analyse du puce à ADN a identifié 12 gènes surexprimés par FGF8, incluant SPRY2, NR4A1, XIRP1, BAMBI, EGR1, FOS et FOSL1. A l’inverse, FGF18 n’a régulé aucun gène de manière significative. Les analyses de PCR ont confirmé l’augmentation d’ARNm codant pour EGR1, EGR3, FOS, XIRP1, FOSL1, SPRY2, NR4A1 et BAMBI après 2 h de traitement. FGF18 a entrainé seulement une augmentation de l’expression de EGR1 après 2 h de traitement parmi tous les gènes testés. Ces résultats démontrent donc que FGF8 et FGF18, malgré leur similarité dans le mode d’activation de leurs récepteurs, agissent sur les cellules de la granulosa via différentes voies de signalisation. FGF8 et FGF18, sont donc tous les deux capables de stimuler l’expression de EGR1, mais les voies de signalisation induites par la suite divergent. / Fibroblast growth factors (FGF) act as local regulators of follicular health and are known to increase granulosa cell (GC) proliferation, reduce apoptosis and decrease steroidogenesis. One exception is FGF18, which appears to be a pro apoptotic member of the FGF8-subfamily while FGF8 has not been reported to alter GC health. These two ligands have similar activation patterns and it could be proposed that all FGF8-subfamilies would have the same response. The objective of this study was to determine if FGF8 and FGF18 activate the same early response genes in cultured bovine GC. To address this we cultured GC in serum free medium for five days. On day 5, cells were challenged with FGF8 or FGF18. We used a microarray approach to identify early response genes altered by FGF8 and FGF18, and data were confirmed by real-time PCR in an independent time-course experiment. Microarray identified 12 genes up-regulated by FGF8, including SPRY2, NR4A1, XIRP1, BAMBI, EGR1, FOS and FOSL1. In contrast FGF18 did not result in significant regulation of any gene. PCR analysis confirmed the stimulation of abundance of mRNA encoding EGR1, EGR3, FOS, XIRP1, FOSL1, SPRY2, NR4A1 and BAMBI after 2 hours of challenge. FGF18 resulted in an increase of EGR1 mRNA abundance at 2 h, but not of the other genes tested. These results demonstrate that FGF8 and FGF18, despite reportedly similar receptor activation patterns, act on granulosa cells through different intracellular pathways. Both FGF8 and FGF18 stimulate EGR1 expression, but thereafter their signaling pathways diverge.

Dissialogangliosídios, como GD3 e derivados são marcadores da progressão de melanomas. Para avaliar as possíveis funções desta molécula, transfectamos células de melanócitos com o gene da enzima ST8Sia I, que converte GM3 em GD3. Mostramos que GD3 não interfere na capacidade proliferativa dessas células, porém a expressão de GD3 mostrou-se associada à sobrevivência celular. Melanomas adquirem autonomia quanto às vias dependentes do fator de crescimento de fibroblastos (FGF-1 e -2). A expressão de GD3 não interfere na resposta proliferativa a estes fatores, porém GD3 e outros glicoesfingolipídios de membrana modulam a resposta migratória induzida por FGF-2. A expressão de GD3 sensibiliza as células à morte celular induzida por diferentes quimioterápicos, como cisplatina e vimblastina; porém, torna as células resistentes ao tratamento com temozolamida. A sensibilização ao tratamento com vimblastina, mas não às outras drogas, depende da presença de GD3, como observado por ensaios de depleção metabólica / Disialoganglioside GD3 and its derivatives are melanoma progression markers. To evaluate the possible roles of these molecules along melanoma progression, we have transfected the GD3 synthase gene (ST8Sia I) in a melanocyte cell line. Accumulation of GD3 did not confer any proliferative advantage to melanocytes. However, GD3 expression was associated with cell survival. The autonomic growth of melanomas is in part related to a constitutive activation of fibroblast growth factor dependent pathways. GD3 expression did not alter the proliferative response to either FGF-1 or FGF-2. However, GD3 and other membrane glycospingolipids modulate the motogenic activity of FGF-2. GD3 expression sensitizes melanocytes to chemotherapeutic agent-induced cell death, as cisplatin and vimblastin. On the other hand, GD3 turned melanocytes more resistant to temozolomide. Chemosensitization to vimblastin, but not to the other drugs, was dependent on the presence of GD3 within the cells, as shown by metabolic depletion of glycosphingolipids

Um dos fatores que regula o córtex adrenal é o hormônio adrenocorticotrópico, ACTH, no entanto, o fator de crescimento de fibroblastos do tipo 2, FGF2, e os peptídeos N-terminais da pro-opiomelanocortina, N-POMC, também podem estar envolvidos. As vias de sinalização das proteínas quinases: ERK, JNK e p38, juntamente com outras vias como PKA, PKC e PI3K/Akt são importantes para a definição trófica das células. Nós analisamos a importância destas vias de sinalização e sua influência na viabilidade, proliferação e morte celular, induzidas pelo ACTH, FGF2 e N-POMC, utilizando inibidores farmacológicos e moleculares em culturas primárias de células adrenocorticais, células glomerulosa e fasciculadas/reticulares. Nossos resultados mostram que as vias mediadoras envolvidas na resposta proliferativa do FGF2 e da N-POMC são, respectivamente, as vias ERK/JNK e ERK/JNK/Akt. Por outro lado, a resposta pró-apoptótica promovida pelo ACTH é mediada pela via p38, provavelmente associada à ausência de ativação das vias relacionadas com a sobrevivência, como as vias ERK e JNK. / One of the factors that regulate adrenal cortex is the adrenocorticotrophic hormone, ACTH, however, the fibroblast growth factor type 2, FGF2) and pro-opiomelanocortin N-terminal peptides, N-POMC, might also be involved. The mitogen-activated protein kinase pathways: ERK, JNK and p38, together with other signaling pathways such as PKA, PKC and PI3K/Akt are important for cells trophic definition. We analyze the importance of these pathways and their influence in viability, proliferation and cell death stimulated by ACTH, FGF2 and N-POMC, using pharmacological and molecular inhibitors in primary culture of adrenocortical cells, glomerulosa and fasciculata/reticularis cells. Our results show that the mediating signaling pathways involved in FGF2 and N-POMC proliferative effects are, respectively, ERK/JNK and ERK/JNK/Akt. On the other hand, the pro-apoptotic response promoted by ACTH is through p38 signaling, probably associated with the absence of activation of other pathways involved with cell survival, like ERK and JNK.