Insulin and insulin-like growth factor signaling increases proliferation and hyperplasia of the ovarian surface epithelium and decreases follicular integrity through upregulation of the PI3-kinase pathway

<p>BACKGROUND: The ovarian surface epithelium responds to cytokines and hormonal cues to initiate proliferation and migration following ovulation. Although insulin and IGF are potent proliferative factors for the ovarian surface epithelium and IGF is required for follicle development, increased insulin and IGF activity are correlated with at least two gynecologic conditions: polycystic ovary syndrome and epithelial ovarian cancer. Although insulin and IGF are often components of in vitro culture media, little is known about the effects that these growth factors may have on the ovarian surface epithelium morphology or how signaling in the ovarian surface may affect follicular health and development.</p><p>METHODS: Ovaries from CD1 mice were cultured in alginate hydrogels in the presence or absence of 5 ��g/ml insulin or IGF-I, as well as small molecule inhibitors of IR/IGF1R, PI 3-kinase signaling, or MAPK signaling. Tissues were analyzed by immunohistochemistry for expression of cytokeratin 8 to mark the ovarian surface epithelium, M��llerian inhibiting substance to mark secondary follicles, and BrdU incorporation to assess proliferation. Changes in gene expression in the ovarian surface epithelium in response to insulin or IGF-I were analyzed by transcription array. Extracellular matrix organization was evaluated by expression and localization of collagen IV.</p><p>RESULTS: Culture of ovarian organoids with insulin or IGF-I resulted in formation of hyperplastic OSE approximately 4-6 cell layers thick with a high rate of proliferation, as well as decreased MIS expression in secondary follicles. Inhibition of the MAPK pathway restored MIS expression reduced by insulin but only partially restored normal OSE growth and morphology. Inhibition of the PI 3-kinase pathway restored MIS expression reduced by IGF-I and restored OSE growth to a single cell layer. Insulin and IGF-I altered organization of collagen IV, which was restored by inhibition of PI 3-kinase signaling.</p><p>CONCLUSIONS: While insulin and IGF are often required for propagation of primary cells, these cytokines may act as potent mitogens to disrupt cell growth, resulting in formation of hyperplastic OSE and decreased follicular integrity as measured by MIS expression and collagen deposition. This may be due partly to altered collagen IV deposition and organization in the ovary in response to insulin and IGF signaling mediated by PI 3-kinase.</p>

Uncovering functionally relevant signaling pathways using microarray-based expression profiling

<p>The introduction of microarray technology to the scientific and medical communities has fundamentally altered the way in which we now address basic biomedical questions. Microarrays technology facilitates a more complete and inclusive experimental approach where alterations in the transcript level of entire genomes can be simultaneously assayed in response to a variety of stimuli. Conceptually different approaches to the development of microarray technology have resulted in the generation of two different array formats: oligonucleotide arrays and cDNA arrays. The application of microarray and related technologies to identify specific targets of defined genes that have clearly been implicated in cancer progression requires a specific experimental approach. The objective of tiffs approach is to define changes in transcriptional profile that occur in response to modulating the expression level of the gene to be studied. The resulting altered expression profile can then be viewed as a blueprint by which that gene effects its cellular function. We have used oligonucleotide array-based expression profiling in collaboration with Affymetrix to identify downstream transcriptional targets of the BRCA1 tumor-suppressor gene as a means of defining its function. BRCA1 has been implicated in at least three functional pathways, namely, mediating the cellular response to DNA damage, as a cell cycle checkpoint protein and in the regulation of transcription. The physiological significance of these properties and their implications for the function of BRCA1 as a tumor-suppressor gene remain to be defined.</p>

CD44-Mediated Activaton of ��5��1-Intergrin, Cortactin and Paxillin Signaling Underpins Ashesion of basal-like breat cancer cells to Endotherlium and Fibronectin- enriched Matrices

CD44 expression is elevated in basal-like breast cancer (BLBC) tissue, and correlates with increased efficiency of distant metastasis in patients and experimental models. We sought to characterize mechanisms underpinning CD44-promoted adhesion of BLBC cells to vascular endothelial monolayers and extracellular matrix (ECM) substrates. Stimulation with hyaluronan (HA), the native ligand for CD44, increased expression and activation of ��1-integrin receptors, and increased ��5-integrin subunit expression. Adhesion assays confirmed that CD44-signalling potentiated BLBC cell adhesion to endothelium and Fibronectin in an ��5B1-integrin-dependent mechanism. Co-immunoprecipitation experiments confirmed HA-promoted association of CD44 with talin and the ��1-integrin chain in BLBC cells. Knockdown of talin inhibited CD44 complexing with ��1-integrin and repressed HA-induced, CD44-mediated activation of ��1-integrin receptors. Immunoblotting confirmed that HA induced rapid phosphorylation of cortactin and paxillin, through a CD44-dependent and ��1-integrin-dependent mechanisms. Knockdown of CD44, cortactin or paxillin independently attenuated the adhesion of BL-BCa cells to endothelial monolayers and Fibronectin. Accordingly, we conclude that CD44 induced, integrin-mediated signaling not only underpins efficient adhesion of BLBC cells to BMECs to facilitate extravasation but initiates their adhesion to Fibronectin, enabling penetrant cancer cells to adhere more efficiently to underlying Fibronectin-enriched matrix present within the metastatic niche.

Mycosis fungoides shows concurrent deregulation of multiple genes involved in the TNF signaling pathway:an expression profile study

<p>Mycosis fungoides (MF) is the most frequent type of cutaneous T-cell lymphoma, whose diagnosis and study is hampered by its morphologic similarity to inflammatory dermatoses (ID) and the low proportion of tumoral cells, which often account for only 5% to 10% of the total tissue cells. cDNA microarray studies using the CNIO OncoChip of 29 MF and 11 ID cases revealed a signature of 27 genes implicated in the tumorigenesis of MF, including tumor necrosis factor receptor (TNFR)-dependent apoptosis regulators, STAT4, CD40L, and other oncogenes and apoptosis inhibitors. Subsequently a 6-gene prediction model was constructed that is capable of distinguishing MF and ID cases with unprecedented accuracy. This model correctly predicted the class of 97% of cases in a blind test validation using 24 MF patients with low clinical stages. Unsupervised hierarchic clustering has revealed 2 major subclasses of MF, one of which tends to include more aggressive-type MF cases including tumoral MF forms. Furthermore, signatures associated with abnormal immunophenotype (11 genes) and tumor stage disease (5 genes) were identified.</p>

Activation of the c-Jun N-terminal kinase (JNK) signaling pathway is essential during PBOX-6-induced apoptosis in chronic myelogenous leukemia (CML) cells

<p>The mitogen-activated protein (MAP) kinase family is activated in response to a wide variety of external stress signals such as UV irradiation, heat shock, and many chemotherapeutic drugs and leads to the induction of apoptosis. A novel series of pyrrolo-1,5-benzoxazepines have been shown to potently induce apoptosis in chronic myelogenous leukemia (CML) cells, which are resistant to many chemotherapeutic agents. In this study we have delineated part of the mechanism by which a representative compound known as PBOX-6 induces apoptosis. We have investigated whether PBOX-6 induces activation of MAP kinase signaling pathways in CML cells. Treatment of K562 cells with PBOX-6 resulted in the transient activation of two JNK isoforms, JNK1 and JNK2. In contrast, PBOX-6 did not activate the extracellular signal-regulated kinase (ERK) or p38. Apoptosis was found to occur independently of the small GTPases Ras, Rac, and Cdc42 but involved phosphorylation of the JNK substrates, c-Jun and ATF-2. Pretreatment of K562 cells with the JNK inhibitor, dicoumarol, abolished PBOX-6-induced phosphorylation of c-Jun and ATF-2 and inhibited the induced apoptosis, suggesting that JNK activation is an essential component of the apoptotic pathway induced by PBOX-6. Consistent with this finding, transfection of K562 cells with the JNK scaffold protein, JIP-1, inhibited JNK activity and apoptosis induced by PBOX-6. JIP-1 specifically scaffolds JNK, MKK7, and members of the mixed-lineage kinase (MLK) family, implicating these kinases upstream of JNK in the apoptotic pathway induced by PBOX-6 in K562 cells.</p>

Endosomal signaling and oncogenesis

<p>The endosomal system provides a route whereby nutrients, viruses, and receptors are internalized. During the course of endocytosis, activated receptors can accumulate within endosomal structures and certain signal-transducing molecules can be recruited to endosomal membranes. In the context of signaling and cancer, they provide platforms within the cell from which signals can be potentiated or attenuated. Regulation of the duration of receptor signaling is a pivotal means of refining growth responses in cells. In cancers, this is often considered in terms of mutations that affect receptor tyrosine kinases and maintain them in hyperactivated states of dimerization and/or phosphorylation. However, disruption to the regulatory control exerted by the assembly of protein complexes within the endosomal network can also contribute to disease among which oncogenesis is characterized in part by dysregulated growth, enhanced cell survival, and changes in the expression of markers of differentiation. In this chapter, we will discuss the role of proteins that regulate in endocytosis as tumor suppressors or oncogenes and how changing the fate of internalized receptors and concomitant endosomal signaling can contribute to cancer.</p>

Tumor necrosis factor receptor expression and signaling in renal cell carcinoma

<p>Clear cell renal cell carcinoma (ccRCC), a tubular epithelial cell (TEC) malignancy, frequently secretes tumor necrosis factor (TNF). TNF signals via two distinct receptors (TNFRs). TNFR1, expressed in normal kidney primarily on endothelial cells, activates apoptotic signaling kinase 1 and nuclear factor-kappaB (NF-kappaB) and induces cell death, whereas TNFR2, inducibly expressed on endothelial cells and on TECs by injury, activates endothelial/epithelial tyrosine kinase (Etk), which trans-activates vascular endothelial growth factor receptor 2 (VEGFR2) to promote cell proliferation. We investigated TNFR expression in clinical samples and function in short-term organ cultures of ccRCC tissue treated with wild-type TNF or specific muteins selective for TNFR1 (R1-TNF) or TNFR2 (R2-TNF). There is a significant increase in TNFR2 but not TNFR1 expression on malignant TECs that correlates with increasing malignant grade. In ccRCC organ cultures, R1-TNF increases TNFR1, activates apoptotic signaling kinase and NF-kappaB, and promotes apoptosis in malignant TECs. R2-TNF increases TNFR2, activates NF-kappaB, Etk, and VEGFR2 and increases entry into the cell cycle. Wild-type TNF induces both sets of responses. R2-TNF actions are blocked by pretreatment with a VEGFR2 kinase inhibitor. We conclude that TNF, acting through TNFR2, is an autocrine growth factor for ccRCC acting via Etk-VEGFR2 cross-talk, insights that may provide a more effective therapeutic approach to this disease.</p>

XBP 1-deficiency abrogates neointimal lesion of injured vessels via cross talk with the PDGF signaling

<p>Objective: Smooth muscle cell (SMC) migration and proliferation play an essential role in neointimal formation after vascular injury. In this study, we intended to investigate whether the X-box-binding protein 1 (XBP1) was involved in these processes.</p><p>Approach and Results: In vivo studies on femoral artery injury models revealed that vascular injury triggered an immediate upregulation of XBP1 expression and splicing in vascular SMCs and that XBP1 deficiency in SMCs significantly abrogated neointimal formation in the injured vessels. In vitro studies indicated that platelet-derived growth factor-BB triggered XBP1 splicing in SMCs via the interaction between platelet-derived growth factor receptor �� and the inositol-requiring enzyme 1��. The spliced XBP1 (XBP1s) increased SMC migration via PI3K/Akt activation and proliferation via downregulating calponin h1 (CNN1). XBP1s directed the transcription of mir-1274B that targeted CNN1 mRNA degradation. Proteomic analysis of culture media revealed that XBP1s decreased transforming growth factor (TGF)-�� family proteins secretion via transcriptional suppression. TGF-��3 but not TGF-��1 or TGF-��2 attenuated XBP1s-induced CNN1 decrease and SMC proliferation.</p><p>Conclusions: This study demonstrates for the first time that XBP1 is crucial for SMC proliferation via modulating the platelet-derived growth factor/TGF-�� pathways, leading to neointimal formation.</p>

Wnt signaling in age-related macular degeneration: human macular tissue and mouse model

<p>BACKGROUND: The wingless-type MMTV integration site (Wnt) signaling is a group of signal transduction pathways. In canonical Wnt pathway, Wnt ligands bind to low-density lipoprotein receptor-related protein 5 or 6 (LRP5 or LRP6), resulting in phosphorylation and activation of the receptor. We hypothesize that canonical Wnt pathway plays a role in the retinal lesion of age-related macular degeneration (AMD), a leading cause of irreversible central visual loss in elderly.</p><p>METHODS: We examined LRP6 phosphorylation and Wnt signaling cascade in human retinal sections and plasma kallistatin, an endogenous inhibitor of the Wnt pathway in AMD patients and non-AMD subjects. We also used the Ccl2 (-/-) /Cx3cr1 (-/-) /rd8 and Ccl2 (-/-) /Cx3cr1 (gfp/gfp) mouse models with AMD-like retinal degeneration to further explore the involvement of Wnt signaling activation in the retinal lesions in those models and to preclinically evaluate the role of Wnt signaling suppression as a potential therapeutic option for AMD.</p><p>RESULTS: We found higher levels of LRP6 (a key Wnt signaling receptor) protein phosphorylation and transcripts of the Wnt pathway-targeted genes, as well as higher beta-catenin protein in AMD macula compared to controls. Kallistatin was decreased in the plasma of AMD patients. Retinal non-phosphorylated-��-catenin and phosphorylated-LRP6 were higher in Ccl2 (-/-) /Cx3cr1 (-/-) /rd8 mice than that in wild type. Intravitreal administration of an anti-LRP6 antibody slowed the progression of retinal lesions in Ccl2 (-/-) /Cx3cr1 (-/-) /rd8 and Ccl2 (-/-) /Cx3cr1 (gfp/gfp) mice. Electroretinography of treated eyes exhibited larger amplitudes compared to controls in both mouse models. A2E, a retinoid byproduct associated with AMD was lower in the treated eyes of Ccl2 (-/-) /Cx3cr1 (-/-) /rd8 mice. Anti-LRP6 also suppressed the expression of Tnf-�� and Icam-1 in Ccl2 (-/-) /Cx3cr1 (-/-) /rd8 retinas.</p><p>CONCLUSIONS: Wnt signaling may be disturbed in AMD patients, which could contribute to the retinal inflammation and increased A2E levels found in AMD. Aberrant activation of canonical Wnt signaling might also contribute to the focal retinal degenerative lesions of mouse models with Ccl2 and Cx3cr1 deficiency, and intravitreal administration of anti-LRP6 antibody could be beneficial by deactivating the canonical Wnt pathway.</p>

Inhibition of protease-ENaC signaling improves mucociliary function in cystic fibrosis airways

Rationale: In cystic fibrosis (CF) a reduction in airway surface liquid (ASL) height<br/>compromises mucociliary clearance, favoring mucus plugging and chronic bacterial infection. Inhibitors of ENaC have therapeutic potential in CF airways to reduce the hyperstimulated sodium and fluid absorption to levels which can restore airways hydration.<br/><br/>Objectives: To determine whether a novel compound (QUB-TL1) designed to inhibit protease/ENaC signaling in CF airways restores ASL volume and mucociliary function.<br/><br/>Methods: Protease activity was measured using fluorogenic activity assays. Differentiated primary airway epithelial cell cultures (F508del homozygotes) were used to determined ENaC activity (Ussing chamber recordings), ASL height (confocal microscopy) and mucociliary function (by tracking the surface flow of apically applied microbeads). Cell toxicity was measured by LDH assay.<br/><br/>Measurements and Results: QUB-TL1 inhibits extracellularly-located CAPs, including prostasin, matriptase and furin, the activities of which are observed at excessive levels at the apical surface of CF airway epithelial cells (AECs). QUB-TL1-mediated CAPs inhibition results in diminished ENaC-mediated Na+ absorption in CF AECs due to internalization of a prominent pool of cleaved (active) ENaC�� from the cell surface. Importantly, diminished ENaC activity correlates with improved airway hydration status and mucociliary clearance. We further demonstrate QUB-TL1-mediated furin inhibition, which is in contrast to other serine protease inhibitors (camostat mesylate and aprotinin), affords protection against neutrophil elastase-mediated ENaC activation and Pseudomonas aeruginosa exotoxin A induced cell death.<br/><br/>Conclusions: QUB-TL1 corrects aberrant CAP activities providing a mechanism to delay or prevent the development of CF lung disease in a manner independent of CFTR mutation.<br/>

Phytochelatin signal tranduction and cadmium chelation in plants

As plantas utilizam diversas estrat��gias de sinaliza����o para reconhecer e responder aos stresses ambientais. A maioria das vias de transdu����o de sinais partilham um sinal gen��rico, normalmente a modula����o dos n��veis intracelulares de Ca2+. Esta por sua vez pode iniciar uma cascata de fosforila����o proteica que finalmente afecta as prote��nas directamente envolvidas na protec����o celular ou culmina em factores de transcri����o que v��o determinar a resposta fisiol��gica ao stresse. A percep����o destes sinais e a compreens��o de como estes podem activar as respostas adaptativas s��o factores-chave para a toler��ncia das plantas a stresses abi��ticos. Um dos principais stresses ab��ticos que restrigem o crescimento das plantas �� a presen��a de metais pesados. A produ����o de fitoquelatinas e a subsequente quela����o dos metais �� o mecanismo mais conhecido de toler��ncia ao stresse met��lico em plantas. Fitoquelatinas (PCs) s��o p��ptidos com grupos tiol que s��o sintetizados atrav��s da transpeptida����o da glutationa (GSH), pela ac����o da enzima fitoquelatina sintase (PCS). No entanto, at�� ao momento, as vias de sinaliza����o que levam �� s��ntese de fitoquelatinas e �� percep����o do stresse met��lico s��o pouco compreendidas. Dentro deste contexto, o presente trabalho foi elaborado com o intuito de elucidar a via de sinaliza����o atrav��s da qual o c��dmio �� detectado pelas c��lulas vegetais e induz a s��ntese de PCs. Quase todos, os estudos de stresses abi��ticos em plantas apontam para o facto de a sua sinaliza����o se basear nos mesmos tipos de sinais moleculares, nomeadamente a sinaliza����o por c��lcio, a fosforila����o proteica e a indu����o de esp��cies reactivas de oxig��nio (ROS). Trabalhos recentes sugerem que a sinaliza����o de PCs poder�� envolver todos estes par��metros. Assim, uma primeira abordagem foi efectuada para compreender a s��ntese de PCs na esp��cie Arabidopsis thaliana, atrav��s da monitoriza������o da actividade de enzimas relacionadas, a ��-EC sintetase, GSH sintetase e a PC sintase (PCS), assim como o tempo necess��rio para o elongamento das PCs e a sua acumula����o. Seguidamente, ao longo deste processo foi analisada a express��o de sinais espec��ficos, associados com sinais de c��lcio, fosforila����o proteica e sinaliza����o por ROS. A import��ncia destes factores na s��ntese de PCs foi tamb��m avaliada atrav��s do uso de moduladores farmacol��gicos de c��lcio e fosfatases proteicas e tamb��m pela indu����o de stresse oxidativo. Os resultados demonstraram novos dados sobre o papel do c��lcio e da fosforila����o proteica na produ����o de PCs e na s��ntese de GSH, revelando que a actvidade da PCS �� regulada por fosforila����o e que a sinaliza����o de c��lcio pode mediar a s��ntese de GSH. O envolvimento da sinaliza����o de ROS na s��ntese de GSH, atr��ves de crosstalk com a sinaliza����o de c��lcio tamb��m foi proposta. Assim, os resultados aqui apresentados descrevem uma poss��vel via de sinaliza����o de c��dmio nas plantas e da indu����o de fitoquelatinas. Este trabalho poder�� ser portanto muito ��til na implementa����o de novas metodologias de agricultura sustent��vel e pr��ticas de fitorremedia����o em solos contaminados com metais pesados.

Regulation of single exocytotic events by the cAMP signaling pathway

Permanece por esclarecer como a via de sinaliza����o do cAMP modula a exocitose regulada. Os principais objetivos deste trabalho foram: i) avaliar o efeito do cAMP nos eventos exocit��ticos, nas propriedades dos poros de fus��o e na secre����o hormonal; ii) perceber o impacto da sinaliza����o por cAMP-HCN na exocitose e nas propriedades do poro de fus��o; e iii) estudar as propriedades do poro de fus��o na presen��a de um agente neurot��xico comum, como o alum��nio. Lactotrofos, isolados a partir da hip��fise anterior de ratos Wistar machos, foram usados como modelo celular. Os eventos unit��rios de fus��o exocit��tica e a prolactina (PRL) libertada foram avaliados, respetivamente, em ensaios eletrofisiol��gicos efectuados segundo a t��cnica de contacto herm��tico no modo sobre a c��lula aderida �� pipeta porta-el��trodo e com recurso a m��todos imunol��gicos de dete����o. Os n��veis intracelulares de cAMP foram aumentados por 3-isobutil-1-metilxantina (IMBX), forscolina e N6,2'-O-dibutiril adenosina- 3',5'-monofosfato c��clico (dbcAMP). A express��o dos canais HCN foi determinada por Western-blot, qRT-PCR e imunocitoqu��mica em combina����o com microscopia confocal. Culturas prim��rias de lactotrofos foram tamb��m transfetadas com DNA plasm��dico que codifica HCN2 juntamente com a prote��na-verde-fluorescente e um agente farmacol��gico foi usado para avaliar o efeito de cAMP-HCN na exocitose. Observou-se que os lactotrofos responderam �� forscolina e ao dbcAMP libertando PRL de um modo bif��sico e dependente da concentra����o, uma vez que a secre����o aumentou e diminuiu, respectivamente, na gama de baixas e altas concentra����es. Os compostos que elevaram os n��veis de cAMP aumentaram os eventos transientes e impediram a fus��o completa. Al��m disso, o dbcAMP promoveu o aparecimento de eventos exocit��ticos transientes de elevada periodicidade, cujos poros de fus��o, de maior di��metro, se mativeram abertos durante mais tempo. A express��o das quatro isoformas de HCN foi confirmada nos lactotrofos ao n��vel do mRNA e, tal como no cora����o, rim e hip��fise, o mais abundante codifica a isoforma HCN2. Nos lactotrofos com sobre-express��o desta isoforma, o dbcAMP n��o s�� aumentou a frequ��ncia dos eventos transientes e a condut��ncia dos poros, mas tamb��m a frequ��ncia dos eventos de fus��o completa. Enquanto o bloqueador dos canais HCN, ZD7288, reduziu a frequ��ncia dos eventos transientes e de fus��o completa desencadeados por dbcAMP e diminuiu o di��metro dos poros de fus��o. A simult��nea diminui����o da liberta����o de PRL, da frequ��ncia dos eventos transientes e do di��metro dos poros de fus��o representaram as principais altera����es observados ap��s pr��-tratamento dos lactotrofos com concentra����o micromolar de alum��nio. Em conclus��o, os resultados demonstram que elevados n��veis de cAMP reduzem a secre����o de PRL devido �� estabiliza����o dos poros de fus��o no estado de maior abertura. Al��m disso, a via de sinaliza����o cAMP-HCN afecta a actividade exocit��tica e modifica as propriedades dos poros de fus��o, que parecem ser igualmente importantes na citotoxicidade induzida por alum��nio.

The role of lymphotoxin-B receptor signaling in t-cell acute lymphoblastic leukemia development

Disserta����o de mest., Ci��ncias Biom��dicas, Faculdade de Ci��ncias e Tecnologia, Univ. do Algarve, 2010

Estudo da interac����o de complexos de van��dio com a ca2+-atpase de ret��culo sarcoplasm��tico: an��lise estrutural e funcional

A bomba de c��lcio de ret��culo sarcoplasm��tico �� uma das prote��nas mais extensivamente estudadas, capaz de interagir com v��rias esp��cies e compostos de van��dio. Combinando-se estudos de fluoresc��ncia com ensaios cin��ticos de transporte e liga����o de 45Ca �� ATPase, avaliou-se o efeito de tr��s complexos de van��dio na fun����o bioenerg��tica e estrutural de Ca2+-ATPase. Demonstrou-se que concentra����es pr��ximas dos valores de IC50 (para a hidr��lise de ATP) de BMOV-V(IV) e de PDC-V(V) n��o inibem significativamente a acumula����o de 45Ca por sarcoves��culas. Por outro lado, o complexo PDC-V(V) mostrou ser capaz de estimular a liga����o de 45Ca ao ret��culo sarcoplasm��tico, sugerindo que este complexos pode interagir com o dom��nio de liga����o de c��lcio �� bomba. V��rios estudos de fluoresc��ncia mostraram que BMOV-V(IV) e PDC-V(V) poder��o ser capazes de induzir a conforma����o E2 (tal como solu����es de ���decavanadato��� e de ���monovanadato���) e E1 de Ca2+-ATPase (tal como solu����es de ���metavanadato���), respectivamente. Apesar de o composto HAIDA-V(IV) previlegiar a conforma����o E1 (devido �� sua elevada afinidade para i��es Ca2+), inibiu significativamente o transporte e a liga����o de 45Ca, o que sugere que possa interagir com os locais de uni��o de c��lcio. Os resultados obtidos s��o consistentes com a forma����o de um aducto entre o composto de van��dio e a prote��na, o que sugere um efeito na homeostasia intracelular de c��lcio, nos sistemas de contrac����o muscular e, inclusive, nas vias de ac����o de insulina. Cada um dos tr��s complexos promoveu respostas distintas na Ca2+-ATPase, sugerindo uma evidencia de actividades biol��gicas diversas em fun����o da esp��cie qu��mica de V e do ambiente de coordena����o.

Role of ��-adrenergic signaling in ovarian cancer cells biology

Tese de mestrado. Biologia (Biologia Evolutiva e do Desenvolvimento). Universidade de Lisboa, Faculdade de Ci��ncias, 2014