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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Quality of Life and Functional Outcomes in Men with Localized Prostate Cancer

Johansson, Eva January 2011 (has links)
Quality-of-life and functional outcomes are important in the choice of treatment for men with localized prostate cancer. These issues were investigated in the present thesis. All living 400 men randomized to radical prostatectomy or watchful waiting from 1989 to 1999 in the Scandinavian Prostate Cancer Group Number 4 (SPCG-4) were included. An additional 281 men compromised an age-matched control group. Physical symptoms, symptom-induced stress, sense of well-being and self-assessed quality of life were evaluated by a study-specific questionnaire. Results showed that prostate cancer men, regardless if they were allocated to radical prostatectomy or watchful waiting were suffering of long term adverse effects, mainly erectile dysfunction, urinary leakage and voiding symptoms. In the prostatectomy group, erectile dysfunction and urinary leakage were often consequences of surgery; in the watchful waiting group the side-effects could be caused by tumor progression. The quality of life deteriorated over time. High self-assessed quality of life was reported by 35 % in the radical, 34 % in watchful-waiting, and 43 % in the control groups after a median follow-up time of 12.2 years. The SPCG-4 men significantly more often reported anxiety than did controls. Erectile dysfunction was associated with the most negative influence on quality of life in both SPCG-4 groups. Men in the prostatectomy group were more distressed by erectile dysfunction than watchful waiting. Androgen deprivation therapy had negative effects on all psychological parameters, including quality of life, for the watchful waiting but not for the prostatectomy group. Information about the prostate-cancer disease was significantly higher in the radical-prostatectomy group than in watchful waiting. Check-ups were associated with worry, especially for those on androgen deprivation therapy. Open radical prostatectomy led to an increased rate of inguinal hernia compared with robot-assisted technique. In conclusion, the data of this thesis emphasize that it takes more than a decade to understand the patterns of adverse effects and time dimension of their occurrence for each treatment. Consideration of quality of life has a high priority to aid the ageing man through the shifting scenarios of localized prostate cancer.
242

The expression and regulation of membranetype matrix metalloproteinases (MT-MMPS) in prostate cancer

Palliyaguru, Tishila Sepali January 2005 (has links)
Prostate cancer (PCa) represents the most frequently diagnosed cancer and the second leading cause of cancer death in males. Initial development and progression of the disease is mainly regulated by androgens. However, the pathology of the disease may progress to a loss of hormone dependence, resulting in rapid growth and a metastatic phenotype. Invasion and metastasis of tumour cells results from the degradation of the basement membrane (BM) and extracellular matrix (ECM). The degradation of the BM and ECM is in part mediated by a family of proteinases called the matrix metalloproteinases (MMPs). Currently more than 20 members of the MMP family have been identified and they are further divided in to sub-classes according to their protein structure. Collectively, MMPs are capable of degrading essentially all ECM components. High expression of some MMPs correlates with a malignant phenotype of various tumours. This study focused on the expression and regulation of a sub-class of MMPs called the membrane-type MMPs (MT-MMPs) in PCa. To date 6 MT-MMPs have been identified and they are characterized by a transmembrane domain, followed by a short cytoplasmic tail (MT1-, MT2-, MT3- and MT5-MMPs) or a glycosylphosphatidylinositol (GPI) moiety (MT4- and MT6-MMPs). MT-MMPs are thought to play a key role in tumour cell invasion by virtue of their ability to activate MMP-2 (a secreted MMP, which is implicated in many metastatic tumours) and their direct degradation activity on ECM components. Elevated MT-MMP expression has been shown in breast, colon, skin, stomach, lung, pancreas and brain cancers. Until very recently there had been no studies conducted on MT-MMPs in PCa. The few studies preceding or occurring in parallel with this one, have mainly reported the mRNA expression of these enzymes in PCa. Most studies have focused on MT1-MMP. Thus, at the commencement of this project there were many unexplored aspects of the expression and regulation of the broader MT-MMP family in PCa. The aims of this study were to examine: 1 a) The expression of MT-MMPs in prostate cancer cell lines using RT-PCR and western blot analysis and b) expression of MT1-MMP and MT5-MMP in BPH (benign prostatic hyperplasia) and PCa clinical tissue sections by immunohistochemistry. 2) The regulation of MT1-MMP, MT3-MMP and MT5-MMP in PCa cell lines by Concanavalin A (Con A), phorbol-12-myristate 13-acetate (PMA), dihydrotestosterone (DHT) and insulin-like growth factors I and II (IGF I and IGF II) using western blot analysis. In this study RWPE1, a transformed but non-tumorigenic prostate cell line was used as a "normal" prostate cell model, ALVA-41 and LNCaP as androgen-dependent PCa cell models and DU-145 and PC-3 as androgen-independent PCa cell models. The mRNA expression for the 6 MT-MMPs was determined by RT-PCR. The results indicate that MT1- and MT3-MMP were detected in all cell lines. This is the first study to report MT1-MMP mRNA expression in LNCaP cells and MT3-MMP mRNA in DU-145 cells. MT2-MMP mRNA was detected in only LNCaP and DU-145 cells, whilst MT5-MMP was detected in PC-3, DU-145 and LNCaP cells. nterestingly, MT2-, MT4-, MT5- or MT6-MMP mRNA expression was not detected in the "normal" cell line RWPE1, perhaps indicating an induction in gene transcription in tumour cells. MT4-MMP mRNA was only detected in the androgen-independent cell lines, indicating a potential role in the invasion and metastasis processes of the aggressive androgen-independent PCa. In this study, very low expression of MT6-MMP was detected only in LNCaP and DU-145 cells. Previously there had been no reports on the expression of MT6-MMP in the normal or cancerous prostate. Due to the mRNA of MT1-, MT3- and MT5-MMPs being the predominant MT-MMPs expressed in the current study, and the availability of suitable antibodies against them, the protein expression of these three MT-MMPs was studied by western blot analysis. MT1-, MT3- and MT5-MMP protein expression was detected in the cell lysates and conditioned medium (CM) of RWPE1, LNCaP and PC-3 cells. For each MT-MMP, various protein species were detected including putative proforms, mature (active) forms, processed or fragmented forms as well as soluble or shed forms. The presence of soluble or shed forms of MT-MMPs in the CM of cultures of "normal" and PCa cells could imply one of the following mechanisms: ectodomain shedding by either extracellular sheddases, the secretion of intracellular processed proteins without the transmembrane domain, the release of membrane vesicles containing membrane-bound enzymes, or the presence of alternatively spliced mRNA, which gives rise to MT-MMPs without a transmembrane domain. Further characterization of these various forms, including their amino acid sequence, is required to fully elucidate their structural composition. Despite the detection of the mRNA, we did not detect the cell-associated proteins of MT1-MMP and MT5-MMP and only very low expression of MT3-MMP in DU-145 cells (CM of DU-145 cells were not screened for soluble forms of the enzymes). This is the first study to report MT5-MMP expression at the protein level in prostate derived cell lines. Immunohistochemistry was carried out on benign prostatic hyperplasia (BPH) and PCa clinical tissues using MT1- and MT5-MMP antibodies to determine their cellular localisation in benign and cancer glands. MT1- and MT5-MMPs were expressed in BPH and moderate and high grade PCa. MT1-MMP expression was highest in moderate grade cancer compared to BPH and high grade cancer. MT1-MMP expression was predominantly observed in the cytoplasm of secretory epithelial cells of both benign and cancer glands, although in cancer glands, some nuclear staining was also observed. Stromal expression of MT1-MMP was only observed in high grade cancer. This study is the first to report the immunolocalization of MT5-MMP outside the brain and in kidneys of diabetic patients. MT5-MMP was predominantly expressed in the cytoplasm of the secretory cells in benign glands. In the cancer glands, staining was heterogeneous with low to intense staining, mainly in the nuclei, plasma membrane and cytoplasm of secretory epithelial cells. Stromal expression of MT5-MMP was only observed in cancer tissues, particularly in high grade cancer. To study the regulation of MT-MMPs in PCa, we treated LNCaP and PC-3 cells, with either Con A, PMA, DHT or IGF-I and -II and studied the protein expression of MT1-, MT3- and MT5-MMPs by western blot analysis. Con A and PMA have been shown to stimulate MMP expression in other cell systems. Con A treatment showed a general increase in the protein expression of MT1-, MT3- and MT5-MMPs. By far the greatest induction by Con A observed was the nearly 4 fold increase in MT5-MMP expression caused by 40μg/mL Con A treatment of PC-3 cells. PMA treatment of LNCaP and PC-3 cells appeared to increase shedding or secretion of all three MT-MMPs in to the CM. This increase in the soluble forms corresponded to a decrease in cell-associated forms in LNCaP cells. Treatment of LNCaP with DHT alone and treatment of LNCaP and PC-3 cells with IGF-I and -II alone failed to detect any change in expression of MT1-MMP. The information gathered in this study on MT-MMPs with respect to cellular localization, expression levels and regulation by growth factors or chemicals that mimic their actions, will aid in our understanding of the role of MT-MMPs in PCa. This study provides strong preliminary data for further research, particularly with respect to functional studies of MT-MMPs in PCa. Understanding the processes which govern the actions of such proteins as these will provide potential insights into development of new management and therapeutic regimens to prevent cancer progression.
243

Recombinant production and in silico analysis of the Androgen receptor ligand binding domain

Simila, Henry Allan January 2006 (has links)
The androgen receptor (AR) fulfils important roles for both sexes. By mediating the biological function of androgens, the AR has remained the target for endocrine therapies treating prostate cancer. The AR also determines the effectiveness of medroxyprogesterone acetate (MPA) in treating AR positive breast cancer. Every man will be affected by prostate cancer if he lives long enough. Prostate cancer continues to be a leading cause of death for males despite research into this cancer covering more than 60 years since Huggins' seminal 1941 study showing that androgens play a key role in this cancer. Unfortunately, significant advances have not been forthcoming and the effect of treatment has remained largely the same over past decades, whereby initial treatment provides temporary remission but eventually advanced cases become refractory to further intervention and the disease recurs in a more aggressive form. A plethora of factors are exquisitely sensitive to minute changes in the AR's structural profile, which can be altered by a single mutation, resulting in aberrant activity. A principal feature of these variant ARs associated with prostate cancer, is enhanced capacity to bind a number of molecules other than its cognate ligand, dihydrotestosterone (DHT). The promiscuous activity of this receptor leads to continued AR signalling and stimulus for the cancer despite low androgen levels induced by treatment regimes. A key question is whether mutations occurring within the AR occur as a result of cancer or contribute to the propagation of the cancer. Recent research has demonstrated that treatments incorporating anti-androgens such as flutamide, which are designed to impede prostate cancer progression by inhibiting AR activity, may actually provide selective pressure favouring somatic mutation of the receptor to take place. The specific changes to the AR which are responsible for gains of function have not been resolved as their crystal structures, which are used to provide conformational analysis of proteins, are tremendously problematic to produce with little success found in literature. Generating representative crystals of the AR protein involves producing soluble recombinant protein. Unfortunately the AR is prone to aggregation and is highly unstable, especially in the presence of antagonistic molecules or absence of a stabilising ligand, preventing the protein from being maintained in the soluble state required for crystallization. In order to produce sufficient quantities of soluble material for crystallization, the androgen receptor's ligand binding domain (LBD) was produced as a recombinant protein in Escherichia coli bacteria strain BL21 (DE3) in the presence of DHT, flutamide, as well as in the absence of ligand. Since soluble unbound AR-LBD has not been produced until now, the bacterial culture containing no ligand was further processed to the stage of cleaving the purification tag from the recombinant protein and represents considerable progress into producing soluble material for crystallizing the troublesome yet considerably important AR in the absence of ligand. Although distinct from prostate cancer in males, AR activity in breast tissue is also a factor determining the action of drugs, such as MPA, included in therapies aimed at breast cancer. The use of MPA has declined primarily due to its adverse effects including unsuccessful generation of a biological response, as well as the advent of other drugs administered for hormonal therapies treating breast cancer. Alternative drugs are needed when breast cancer therapies fail as tumours develop resistance to primary drugs. Although there are a number of drugs on the market, success would be maximised if the determined therapy is matched with the patient, based for example, on their genetic makeup. There is a conundrum whereby some patients with an AR do not respond to MPA, a drug normally recognised by the receptor. In clinical trials it was discovered that an AR with threonine instead of methionine at residue 780 (M780T) fails to activate in response to MPA, but the exact mechanism has remained elusive and needs to be answered at the molecular level. The X-ray crystallographic studies that generate 3D images of macromolecules and wet chemistry, which have traditionally been used to provide insight into science in these dimensions, are incorporated with computer based molecular simulation. This is both complementary and distinct to traditional scientific methodologies, enabling further elucidation of protein-protein interactions, and the influence applied to such inter-relations by natural and drug ligands. This approach has been used, and is continually developed, to understand the binding mechanisms of current drugs as well as designing new drugs. In order to produce a receptor representing the M780T variant, the crystal structure representing the AR-LBD was mutated in silico, into which MPA was then docked. It was found that MPA binds into the M780T AR-LBD with considerably more spatial displacement compared to the position of DHT in the crystal structure, and is predicted to be the primary reason for the inability of MPA to activate this variant AR. The clarification of MPA binding and failure to elicit a response from the variant AR is significant for a cohort of breast cancer patients, as not only does the presence of an AR in the tumour determine the effectiveness of MPA, but correct composition of the AR, specifically, the absence of a M780T mutation. In the absence of this AR mutation, MPA could effectively be used either as an alternative to primary drugs, or in secondary therapies when primary therapies fail. Aberrant activity of variant ARs in response to MPA should also be taken into consideration when analysing drug studies about the effectiveness of MPA. The findings on the loss of response to MPA by the M780T variant AR have been included in the journal article &quotDecreased Androgen Receptor Levels and Receptor Function in Breast Cancer Contribute to the Failure of Response to Medroxyprogesterone Acetate" appearing in the September 2005 issue of Cancer Research journal.
244

The anti-proliferative effects of thiazolidinediones and non-steriodal anti-inflammatory drugs on androgen-independent prostate cancer

Chew, Angela Christine January 2009 (has links)
[Truncated abstract] In recent years a better understanding of the biology of PPAR , a nuclear transcription factor, has emerged, leading to a resurgence in targeting PPAR for chemotherapy. The family of synthetic PPAR agonists, the thiazolidinediones (TZDs), and non-steroidal anti-inflammatory drugs (NSAIDs) have been implicated in the inhibition of cell proliferation, apoptosis and cell cycle arrest of androgen-sensitive (LNCaP) and androgen-independent (PC-3 and DU145) prostate cancer cells generating much interest in their use for potential curative cancer therapies. In light of the potential use of TZDs and NSAIDs in prostate cancer prevention and their ability to induce inhibitory effects in vitro and in vivo, the first aim of this project was to undertake a comprehensive study of the effects of ciglitazone (TZD) and indomethacin (NSAID) on the androgen-independent prostate cancer cell line DU145, using standardised concentrations and time-points to compare the effects of TZDs and NSAIDs on cell proliferation, cell cycle and apoptosis. Treating the cells with either 10 µM ciglitazone or 10 µM indomethacin resulted in a time-dependent decrease in DU145 cell proliferation. The anti-proliferative effects were found to be in-part attributed to the slowing of cell progression through the G1/S-phase checkpoint of the cell cycle, and in the case of ciglitazone, apoptosis also played a role in its anti-proliferative effects in this cell line. Interestingly, although indomethacin failed to induce apoptosis, its antiproliferative effects were more potent than ciglitazone. The second aim of this project was to further investigate the underlying mechanisms responsible for the anti-proliferative effects of ciglitazone and indomethacin by evaluating their ability to modulate PPAR mRNA and protein expression, and to induce PPAR transcriptional activity. ... In addition, ligandinduced regulation of secreted frizzled related protein 4 (sFRP4) expression, a Wnt/ - catenin antagonists, was investigated. It was demonstrated that both ciglitazone and indomethacin attenuated Wnt/ -catenin signalling via the down-regulation of total - catenin levels within the cells, inhibition or slowing of the translocation of cytoplasmic -catenin into the nucleus and inhibition of cyclin–D1 expression An inverse relationship between PPAR and -catenin protein levels was also detected, suggesting that PPAR may directly bind to -catenin itself. sFRP4 expression was transiently upregulated by ciglitazone and indomethacin-treatment, suggesting that the antiproliferative effects of the ligands may be mediated in part through regulation of sFRP4 mRNA and protein levels. In summary, the anti-proliferative effects of ciglitazone and indomethacin on the androgen-independent prostate cancer cell line, DU145, described in this thesis are progressive steps in characterising the role of PPAR in prostate cancer cell proliferation. The identification of indomethacin as a more potent PPAR agonist than ciglitazone represents a novel target for the development of preventative strategies for advanced disease, and the relationship between PPAR and the Wnt/ -catenin signalling pathway provide an insight into the mechanisms involved in the anti-proliferative effects of ciglitazone and indomethacin. Further studies into this relationship would advance help identify novel preventative and curative therapeutic strategies for advanced prostate cancer.
245

Estrogenic and androgenic potential of municipal sewage in Australia and New Zealand

Leusch, F. D. L. January 2004 (has links)
Studies in Europe, Japan, and North America have reported that wild fish exposed to treated sewage effluents can exhibit significant physiological and reproductive abnormalities consistent with exposure to hormonally active chemicals. The main objective of this research project was to examine the estrogenic and androgenic activity in treated sewage to determine the risk associated with treated sewage discharges in Australia and New Zealand. Several bioassays, including a sheep estrogen receptor and a rainbow trout androgen receptor binding assay, were set up and validated with model compounds. The assays were then used to measure the estrogenic and androgenic activity in sewage samples from 15 municipal sewage treatment plants (STP) utilizing a variety of treatment technologies. Raw sewage samples contained high levels of both estrogenic and androgenic activity, up to 185 ng/L estradiol equivalents (EEq) and up to 9330 ng/L testosterone equivalents (TEq), respectively. Secondary treatment processes such as activated sludge had the greatest impact on removal of biological activity from the wastewater. The estrogenic and androgenic activity in final treated effluents were <1 to 4.2 ng/L EEq and <6.5 to 736 ng/L TEq, respectively. Based on lowest observable effective concentrations reported in the literature, these levels are unlikely to induce biological effects in exposed fish in the short term. To examine potential long-term effects, resident mosquitofish chronically exposed to undiluted treated sewage were sampled. Several morphological biomarkers indicative of endocrine disruption were measured and compared with mosquitofish captured at a reference site. Mosquitofish captured in a constructed wetland for tertiary treatment of secondary treated sewage exhibited morphological differences such as elongated anal fins consistent with exposure to androgenic chemicals, although this effect was not measurable in fish collected at sites further downstream or at any of the other sites. Based on these results, it is unlikely that mosquitofish populations would be significantly affected by exposure to final treated sewage. A reverse transcription real-time polymerase chain reaction (RT-PCR) method to measure the production of a female-specific protein (vitellogenin) mRNA in adult male mosquitofish was developed, and this could be used as a rapid test to detect early changes in individuals exposed to estrogenic activity.
246

Vasomotor symptoms in men and the role of calcitonin gene-related peptide /

Spetz, Anna-Clara January 2002 (has links) (PDF)
Diss. (sammanfattning) Linköping : Univ., 2002. / Härtill 4 uppsatser.
247

Efeitos da castração e da reposição hormonal com undecanoato de testosterona na bexiga urinária de ratos: análise estrutural, ultra-estrutural e bioquímica / Effects castration and hormonal replacement in the rat urinary bladder, structural, ultrastructural and biochemical analysis

Carla Braga Mano Gallo 04 November 2009 (has links)
Evidências recentes em animais e humanos sugerem que níveis adequados de testosterona são necessários para as funções adequadas de diversos órgãos do sistema urogenital, incluindo a bexiga urinária. Estudos sobre os efeitos da testosterona na estrutura da parede da bexiga são raros. Portanto, o objetivo do presente trabalho é avaliar através de métodos qualitativos e quantitativos, as alterações estruturais da parede vesical de ratos submetidos à castração cirúrgica, bem como o papel da reposição hormonal na reversão das possíveis alterações estruturais. Foram usados 24 ratos machos Sprague-Dawley com aproximadamente 12 semanas de idade. Os animais foram divididos em 3 grupos compostos de 8 animais cada e tratados como a seguir. C = Grupo Castrado os animais foram submetidos a orquiectomia e sacrificados após 2 meses, S = Grupo Simulado os animais foram submetidos a operação simulada e sacrificados após 2 meses, T = Grupo Testosterona os animais foram submetidos a castração e após 1 mês foram submetidos a reposição hormonal com undecanoato de testosterona em dose única subcutânea de 100 mg/kg (T) e após 1 mês da reposição hormonal foram sacrificados. Foram realizadas análises quantitativa e qualitativa do colágeno (usando histoquímica, histomorfometria, bioquímica e microscopia eletrônica de varredura), e análise histomorfométrica do músculo liso e das fibras do sistema elástico na parede da bexiga em controles e em ratos submetidos apenas a castração, e em ratos submetidos a castração e reposição hormonal. A análise morfométrica da altura do urotélio não apresentou diferença entre os grupos. Não houve diferença significativa na análise quantitativa do colágeno, tanto por histomorfometria quanto por bioquímica. Entretanto, a análise qualitativa mostrou diferenças do colágeno no grupo castrado quando comparado aos controles e aos ratos com reposição hormonal. Existiu uma diminuição significativa nos valores absolutos das fibras do sistema elástico no grupo castrado. Por outro lado, o músculo liso apresentou um aumento significativo na massa muscular por densidade de área nos ratos castrados; entretanto, a contagem dos núcleos das células musculares não apresentou variação entre os grupos, demonstrando que o aumento foi devido a hipertrofia muscular e não por aumento do número de células. Interessantemente, a reposição hormonal com testosterona foi capaz de reverter todas as alterações observadas. Os resultados sugerem que a reposição hormonal, mesmo quando instituída em fase tardia, é efetiva na reversão das alterações da parede da bexiga produzidas por hipogonadismo secundário. / Recent evidences in animals and humans have suggested that adequate levels of testosterone are necessary to adequate functions of diverse organs of the urogenital system, including the urinary bladder. Studies on the effects of testosterone in the bladder wall structure are rare. Therefore, the objective of the present study is to evaluate, through qualitative and quantitative methods, the structural alterations in the bladder wall of rats submitted to surgical castration as well as the role of hormonal replacement in reversing the possible structural alterations. We used 24 male Sprague-Dawley rats that were approximately 12 weeks of age. The animals were divided into 3 groups composed of 8 animals each and treated as follows. Group C = group that underwent orchiectomy and were sacrificed after 2 months, Group S = sham group sacrificed after 2 months, and Group T = group that underwent orchiectomy, and after 1 month underwent testosterone replacement with a subcutaneous single dose of testosterone undecanoate at 100 mg/kg (T) and after 1 month of hormonal replacement, the animals were sacrificed. We performed a qualitative and quantitative analysis of collagen (by using histochemistry, histomorphometry, biochemistry, and scanning electron microscopy), and a histomorphometric analysis of smooth muscle and elastic system fibers in bladder wall of controls and rats submitted to orchiectomy alone and with hormonal replacement. The histomorphometric analysis on the epithelial height did not show differences among the groups. There was no statistically significant difference in the quantitative analysis for collagen, both by histomorphometry and biochemistry. Nevertheless, the qualitative analysis showed differences in collagen in the castrated group, when compared to controls and to rats with hormonal replacement. There was a significant decrease in the absolute values of elastic system fibers in the castrated group. On the other hand, the smooth muscle presented a significant increase in muscular mass by density of area in castrated rats; nevertheless, the counting of muscle cells nuclei did not present variation among the groups, demonstrating that this increase was due to cellular hypertrophy rather than by an increase in cells number. Interestingly, the hormonal replacement with testosterone was able to reverse all alterations observed. The results suggest that hormonal replacement, even when instituted at a late stage, is effective in reversing the bladder wall alterations produced by secondary hypogonadism.
248

Voie de signalisation des androgènes, altérations génomiques et progression du cancer de la prostate / Androgen receptor signaling pathway, genomic alterations and prostate cancer progression

Barthélémy, Philippe 01 June 2016 (has links)
La voie de signalisation du récepteur des androgènes (RA) reste une cible thérapeutique privilégiée dans les cancers de la prostate (CaP). Ce travail de thèse a abordé trois thématiques : 1) l’identification et l’étude fonctionnelle des mutations du RA, 2) l’étude du lien existant entre les RA tronqués, résultant de mutations non-sens, et l’angiogenèse tumorale et 3) l’étude exploratoire de l’hétérogénéité tumorale dans les CaP. Au cours de la 1e partie, nous avons identifié 90 mutations du RA à l’aide d’un test fonctionnel chez la levure et émis des hypothèses concernant leur implication dans de potentiels mécanismes de résistance à l’hormonothérapie (HT). La 2e partie nous a permis de montrer un lien entre les variants tronqués et l’expression du VEGF-A, médiateur principal de l’angiogenèse. Enfin dans la dernière partie nous avons étudié, par approche de séquençage à haut-débit, l’hétérogénéité tumorale en fonction du temps et du stade de la maladie. L’ensemble du travail a permis une meilleure connaissance des altérations de la voie de signalisation du RA, leur rôle dans les étapes clés de la progression tumorale et l’évolution des anomalies génomiques. / The androgen receptor signaling pathway (AR) remains a prime therapeutic target in prostate cancer (PCa). This work focused on three topics: 1) the identification of AR mutations and their functional impact, 2) the assessment of a link between the truncated AR, resulting from nonsense mutations and tumor angiogenesis and 3) an exploratory study of tumor heterogeneity in PCa. In the first part, we identified 90 AR mutations using a yeast-based functional assay and speculated about their involvement in potential mechanisms to hormone therapy (HT) resistance. In the second part we assessed a link between the truncated AR and the overexpression of VEGF-A, the main proangiogenic factor. In the last part we investigated the tumor heterogeneity within the primary tumor and metastasis using a whole exome sequencing approach. This work leads to a better knowledge of the AR signaling pathway alterations, their role in the key steps of tumor progression and the evolution of genomic abnormalities.
249

Estudo da biossíntese e regulação de RNAs não-codificadores intrônicos em células humanas / Investigation of the biosynthesis and regulation of intronic noncoding RNAs in human cells

Paulo de Paiva Rosa Amaral 16 October 2006 (has links)
Recentemente, tem sido demonstrado que a maioria dos RNAs transcritos em células humanas são RNAs não-codificadores de proteínas (ncRNAs) originados de íntrons ou regiões intergênicas. Em trabalhos anteriores realizados por nosso grupo, foram descritos longos ncRNAs transcritos de regiões intrônicas de genes codificadores e cuja expressão foi correlacionada ao grau de diferenciação de tumores de próstata, apontando para a relevância fisiológica desta classe de transcritos. Apesar de sua abundância, as propriedades, funções e regulação da grande maioria dos ncRNAs ainda não foram elucidadas. O objetivo do presente trabalho foi investigar a biossíntese de ncRNAs intrônicos em células humanas, primordialmente a contribuição da RNA Polimerase II (RNAP II), bem como aspectos de sua regulação. Primeiramente, o modelo de regulação da expressão gênica por hormônio andrógeno foi utilizado para avaliação da participação direta de um fator de transcrição de RNAP II, o Receptor de Andrógeno (AR), na modulação da transcrição de ncRNAs intrônicos. Utilizando-se a técnica de imunoprecipitação da cromatina, foi detectada a ligação do AR ao elemento de resposta a andrógeno (ARE) presente em um possível promotor de um transcrito intrônico antisenso (derivado do locus Myo5A), cuja expressão é aumentada em células da linhagem LNCaP tratadas com o hormônio. A ligação ao ARE foi induzida pelo tratamento, sugerindo que o efeito do andrógeno na expressão do ncRNA é mediado pelo AR. Em uma segunda abordagem, o efeito da inibição da transcrição por RNAP II com &#945;-amanitina por 24 h em células LNCaP foi avaliado com o uso de microarranjos de oligonucleotídeos representando transcritos total ou parcialmente intrônicos, além de éxons de genes codificadores. A expressão de menos de 20 % dos transcritos intrônicos foi afetada, fração significativamente menor que a observada para os transcritos exônicos (40 %). Ainda que a maioria dos ncRNAs intrônicos diferencialmente expressos tenha sua abundância diminuída, interessantemente, 13 a 16 % foram aumentados, contrastando com aproximadamente 2 a 3 % de exônicos que aumentaram. Os resultados obtidos neste trabalho indicam que a RNAP II atua na transcrição de ncRNAs intrônicos, mas que uma fração considerável pode ser transcrita por outra RNA Polimerase. / It has been recently shown that the bulk of the transcription in human cells is comprised of non-protein-coding RNAs (or noncoding RNAs - ncRNAs) transcribed from introns and intergenic regions of the genome. Previous work from our group has demonstrated that expression of long intronic ncRNAs can be correlated to the degree of prostate tumor differentiation, underscoring the physiological relevance of these transcripts. However, the properties, functions, and regulation of this huge population of ncRNAs remain largely unknown. The present work aimed to investigate the biosynthesis of intronic ncRNAs and aspects of its regulation in human cells, focusing on the contribution of RNA Polymerase II (RNAP II). Initially, the model of regulation of gene expression by androgen hormone was used in order to evaluate the participation of the RNAP II transcription factor Androgen Receptor (AR) in the transcriptional regulation of intronic ncRNAs. Chromatin immunoprecipitation experiments revealed the binding of the AR in an androgen response element (ARE) present in a putative promoter driving the expression of an antisense intronic transcript in Myo5A locus in LNCaP cells. The interaction occurred in an androgen-inducible fashion, along with the up-regulation of the transcript, suggesting that hormone activation occurred in a direct manner mediated by the AR. In a different approach, the effect of RNAP II inhibition with &#945;-amanitin for 24 h in LNCaP cells was analyzed using an oligoarray representing totally and partially intronic transcripts, as well as exons of proteincoding genes. The expression of less than 20 % of the intronic transcripts was affected by the treatment, contrasting to a significantly higher fraction observed for exonic messages (40 %). Moreover, most differentially expressed intronic transcripts were down-regulated, but strikingly 13 to 16 % were up-regulated in cells with blocked RNAP II, while this fraction for exonic transcripts was about 2 %. The results described here demonstrate that RNAP II in fact plays a role in intronic transcription in human cells, but also highlight that another transcriptional system may account for the biogenesis of a fraction of intronic ncRNAs.
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Efeitos da castração e da reposição hormonal com undecanoato de testosterona na bexiga urinária de ratos: análise estrutural, ultra-estrutural e bioquímica / Effects castration and hormonal replacement in the rat urinary bladder, structural, ultrastructural and biochemical analysis

Carla Braga Mano Gallo 04 November 2009 (has links)
Evidências recentes em animais e humanos sugerem que níveis adequados de testosterona são necessários para as funções adequadas de diversos órgãos do sistema urogenital, incluindo a bexiga urinária. Estudos sobre os efeitos da testosterona na estrutura da parede da bexiga são raros. Portanto, o objetivo do presente trabalho é avaliar através de métodos qualitativos e quantitativos, as alterações estruturais da parede vesical de ratos submetidos à castração cirúrgica, bem como o papel da reposição hormonal na reversão das possíveis alterações estruturais. Foram usados 24 ratos machos Sprague-Dawley com aproximadamente 12 semanas de idade. Os animais foram divididos em 3 grupos compostos de 8 animais cada e tratados como a seguir. C = Grupo Castrado os animais foram submetidos a orquiectomia e sacrificados após 2 meses, S = Grupo Simulado os animais foram submetidos a operação simulada e sacrificados após 2 meses, T = Grupo Testosterona os animais foram submetidos a castração e após 1 mês foram submetidos a reposição hormonal com undecanoato de testosterona em dose única subcutânea de 100 mg/kg (T) e após 1 mês da reposição hormonal foram sacrificados. Foram realizadas análises quantitativa e qualitativa do colágeno (usando histoquímica, histomorfometria, bioquímica e microscopia eletrônica de varredura), e análise histomorfométrica do músculo liso e das fibras do sistema elástico na parede da bexiga em controles e em ratos submetidos apenas a castração, e em ratos submetidos a castração e reposição hormonal. A análise morfométrica da altura do urotélio não apresentou diferença entre os grupos. Não houve diferença significativa na análise quantitativa do colágeno, tanto por histomorfometria quanto por bioquímica. Entretanto, a análise qualitativa mostrou diferenças do colágeno no grupo castrado quando comparado aos controles e aos ratos com reposição hormonal. Existiu uma diminuição significativa nos valores absolutos das fibras do sistema elástico no grupo castrado. Por outro lado, o músculo liso apresentou um aumento significativo na massa muscular por densidade de área nos ratos castrados; entretanto, a contagem dos núcleos das células musculares não apresentou variação entre os grupos, demonstrando que o aumento foi devido a hipertrofia muscular e não por aumento do número de células. Interessantemente, a reposição hormonal com testosterona foi capaz de reverter todas as alterações observadas. Os resultados sugerem que a reposição hormonal, mesmo quando instituída em fase tardia, é efetiva na reversão das alterações da parede da bexiga produzidas por hipogonadismo secundário. / Recent evidences in animals and humans have suggested that adequate levels of testosterone are necessary to adequate functions of diverse organs of the urogenital system, including the urinary bladder. Studies on the effects of testosterone in the bladder wall structure are rare. Therefore, the objective of the present study is to evaluate, through qualitative and quantitative methods, the structural alterations in the bladder wall of rats submitted to surgical castration as well as the role of hormonal replacement in reversing the possible structural alterations. We used 24 male Sprague-Dawley rats that were approximately 12 weeks of age. The animals were divided into 3 groups composed of 8 animals each and treated as follows. Group C = group that underwent orchiectomy and were sacrificed after 2 months, Group S = sham group sacrificed after 2 months, and Group T = group that underwent orchiectomy, and after 1 month underwent testosterone replacement with a subcutaneous single dose of testosterone undecanoate at 100 mg/kg (T) and after 1 month of hormonal replacement, the animals were sacrificed. We performed a qualitative and quantitative analysis of collagen (by using histochemistry, histomorphometry, biochemistry, and scanning electron microscopy), and a histomorphometric analysis of smooth muscle and elastic system fibers in bladder wall of controls and rats submitted to orchiectomy alone and with hormonal replacement. The histomorphometric analysis on the epithelial height did not show differences among the groups. There was no statistically significant difference in the quantitative analysis for collagen, both by histomorphometry and biochemistry. Nevertheless, the qualitative analysis showed differences in collagen in the castrated group, when compared to controls and to rats with hormonal replacement. There was a significant decrease in the absolute values of elastic system fibers in the castrated group. On the other hand, the smooth muscle presented a significant increase in muscular mass by density of area in castrated rats; nevertheless, the counting of muscle cells nuclei did not present variation among the groups, demonstrating that this increase was due to cellular hypertrophy rather than by an increase in cells number. Interestingly, the hormonal replacement with testosterone was able to reverse all alterations observed. The results suggest that hormonal replacement, even when instituted at a late stage, is effective in reversing the bladder wall alterations produced by secondary hypogonadism.

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