Telomeres are protective structures at the end of our chromosomes, composed of multiple repeats of the DNA sequence TTAGGG. They are essential for maintaining chromosomal stability by preventing damage and degradation of the chromosome ends. Telomeres are normally shortened with each cell division until a critical length is reached, at which stage cell cycle arrest is induced. Telomere shortening can be prevented in the presence of the telomere-­‐elongating enzyme telomerase. Telomerase is expressed during embryogenesis and in certain normal cell types, but most somatic cells exhibit undetectable levels of telomerase activity. In contrast, most cancer cells express telomerase enabling them to proliferate indefinitely. There is a search for reliable molecular markers that can be used to help predict cancer risk and outcome. The interest of investigating telomere length as a potential biomarker in malignancy has grown rapidly, and both tumors and normal tissues have been in focus for telomere length measurements. In this thesis, telomere length was investigated in breast cancer patients and in patients with renal cell carcinoma (RCC). The breast cancer patients were found to have significantly longer mean telomere length in peripheral blood cells (i.e. immune cells) compared to a tumor-­‐free control group. Moreover, patients with the longest blood telomere length had a significantly worse outcome compared to patients with shorter blood telomeres. In a patient group with clear cell RCC, telomere length was investigated in peripheral blood cells, in tumors and in corresponding kidney cortex. Again, patients with the longest blood telomere length had a significantly worse prognosis compared to those with shorter blood telomeres. In contrast, telomere length in tumor and kidney cortex tissues did not predict outcome per se. Immunological components may play a role in telomere length dynamics as well as in cancer development. We aimed to investigate a possible association between telomere length and certain immunological parameters, including various cytokines and peripheral levels of a blood cell type with suppressor function [regulatory T cells (Tregs)]. In our patients with clear cell RCC, three cytokines correlated significantly with tumor telomere length, but not with telomere length in peripheral blood cells. In a separate patient group with various RCC tumors, blood telomere length correlated positively with the amount of Tregs. It might be speculated that a subset of patients with long blood telomeres has a less efficient immune response due to high Treg levels, contributing to a worse prognosis. Another aim of this thesis was to explore telomere length changes over time. Evaluation of blood samples collected at a 6-­‐month interval from 50 individuals, showed that half of the participants experienced a decline in mean telomere length during the time period. This group had longer telomere length at baseline compared to those who demonstrated increased/stable telomere length. In a separate group of five blood donors, a remarkable drop in telomere length was detected in one donor over a 6-­‐month period, whereas the other donors exhibited only small fluctuations in telomere length. In conclusion, the results of this thesis indicate that blood telomere length has potential to act as an independent prognostic marker in malignancy. Adding to the complexity is the fact that changes in blood telomere length might occur within relatively short time spans, indicating that telomere length is a dynamic character.

Rapid Diagnostic Tests (RDTs) for malaria are restricted to a few biomarkers and antibody-mediated detection. However, the expression of commonly used biomarkers varies geographically and the sensibility of immunodetection can be affected by batch-to-batch differences or limited thermal stability. In this study we aimed to overcome these limitations by identifying a potential biomarker and by developing molecular sensors based on aptamer technology. Using gene expression databases, ribosome profiling analysis, and structural modeling, we find that the High Mobility Group Box 1 protein (HMGB1) of Plasmodium falciparum is highly expressed, structurally stable, and present along all blood-stages of P. falciparum infection. To develop biosensors, we used in vitro evolution techniques to produce DNA aptamers for the recombinantly expressed HMG-box, the conserved domain of HMGB1. An evolutionary approach for evaluating the dynamics of aptamer populations suggested three predominant aptamer motifs. Representatives of the aptamer families were tested for binding parameters to the HMG-box domain using microscale thermophoresis and rapid kinetics. Dissociation constants of the aptamers varied over two orders of magnitude between nano- and micromolar ranges while the aptamer-HMG-box interaction occurred in a few seconds. The specificity of aptamer binding to the HMG-box of P. falciparum compared to its human homolog depended on pH conditions. Altogether, our study proposes HMGB1 as a candidate biomarker and a set of sensing aptamers that can be further developed into rapid diagnostic tests for P. falciparum detection. / Grand Challenges Canada / Revisión por pares

Some people are genetically more vulnerable to stress than others, leading them towards poorer outcomes following stressful events. Mothers' vulnerability to stress may, in turn, influence their children, leading their children towards poor outcomes as well. A biological marker of vulnerability to stress may indicate mothers who are at greater risk for experiencing parenting stress, depression, and less support of the infant's emotional development, and infants who are at greater risk for development of poor emotion regulation and behavior problems. Taste sensitivity to propylthiouracil (PROP) is proposed as a biological marker of stress vulnerability in mothers and children. This research used a bioecological approach to examine extant data from two previous longitudinal studies, both with child and mother data from maternal interviews and video-recorded observations of mother-child interaction. Participants included 121 low-income and 102 middle-income mother-child pairs who were studied for presence of the biological marker in relation to stressful life events, parenting stress, depression, and lower support of infants' emotions. Children were studied for presence of the biological marker in relation to their development of emotion regulation and their later behavior problems. Results revealed that PROP taste sensitivity, as tested in this study, is not likely to be a useful biological marker of higher vulnerability to stress. Although results flowed in the hypothesized direction, few reached statistical significance and most were of small effect size. For depression, results supported previous research, although with smaller effect sizes. In addition, results depended on the sample and source of stress. For low-income mothers the source of stress was stressful life events. For the middle-income sample the source of stress was parenting stress, specifically mother-child dysfunctional interaction. Among mothers with higher PROP taste sensitivity, those from the low-income sample reported more depression whether stressful events were higher or lower, whereas those from the middle-income sample reported more depression when parenting stress, particularly poor mother-child dyadic interaction, was higher. From both samples, mothers' parenting stress or depression at 14 months predicted children's later behavior problems when they were school-age. Children with lower PROP taste sensitivity were more emotionally regulated with their mothers. Because the results were consistent and suggestive, although not conclusive enough to warrant the use of PROP as a biological marker, future research should examine individual situational factors under which PROP taste sensitivity is related to stress vulnerability.

Nanostructured silicon carbide (SiC) is considered today as a good alternative to the conventional materials for various multidisciplinary applications. In this thesis, SiC nanostructures were elaborated by means of electrochemical etching and laser ablation techniques. The first part of the thesis clarifies size-dependence of optical properties as well as importance of local-field effects onto the photoinduced electronic transitions of SiC nanostructures. In the second part of the thesis strong 15-fold photoluminescence enhancement of SiC nanoparticles is ensured by their near-field interactions with multipolar localized plasmons. Further, 287-fold and 72-fold plasmon-induced enhancement factors of two-photon excited luminescence and second harmonic generation is achieved, respectively. The main physical mechanisms responsible for the observed effects were described by three-dimensional finite-difference time domain simulations. Finally, the coupling effect of luminescent SiC nanoparticles to plasmonic nanostructures is used in the enhanced labelling of biological cells on the planar structures. As a perspective, colloidal plasmonic (Au@SiO2)SiC nanohybrids were elaborated and characterized.

Les cancers gastro-intestinaux, en particulier les cancers colorectaux (CCR) et les cancers gastriques (CG), sont des pathologies agressives avec des taux de mortalité élevés dans le monde. Ces cancers sont caractérisés par la dérégulation de voies de signalisation cellulaire telles que les voies Wnt, Notch et Hippo qui jouent un rôle très important dans la tumorigenèse gastro-intestinale. L’activité des différents facteurs de transcription impliqués dans ces voies de signalisation nucléaire est contrôlée par de nombreux corégulateurs transcriptionnels. Ces travaux de thèse ont porté sur deux corégulateurs transcriptionnels initialement identifiés comme des partenaires des récepteurs nucléaires, à savoir RIP140 et LCoR. L’objectif a été d’explorer l’expression de ces deux facteurs de transcription dans les cancers gastro-intestinaux ainsi que leur rôle dans les cancers gastriques principalement au travers du dialogue avec la voie de signalisation Hippo. L’analyse par immunohistochimie de l'expression de RIP140 et LCoR dans les cancers colorectaux et gastriques a montré que les niveaux d’expression de ces deux corégulateurs transcriptionnels sont fortement corrélés. Dans les CCRs, leur expression tend à diminuer dans le tissu tumoral par rapport au tissu normal adjacent, alors que dans les CGs, les niveaux d’expression de RIP140 et LCoR sont significativement plus élevés dans la tumeur que dans l’épithélium sain. Des corrélations significatives ont été observées avec les paramètres clinicopathologiques des patients (stade TNM et différenciation tumorale) ainsi qu’avec d’autres protéines clés impliquées dans la progression et l'invasion tumorale (incluant E-cadhérine et Cox-2). L'analyse de la survie a montré que les patients atteints de CCR avec des tumeurs LCoRlow/RIP140high ont une durée de survie plus longue. Dans le CG, l'expression élevée de RIP140 ou de LCoR a été identifiée comme un marqueur de mauvais pronostic suggérant un rôle clé de ces deux gènes dans cette malignité.Pour mieux cerner le rôle de RIP140 dans le CG, nous avons utilisé les lignées cellulaires MKN45 et MKN74 de cancer de l’estomac humain avec une surexpression ectopique du gène RIP140 ou au contraire avec une diminution de son expression. Nos résultats ont montré que l'expression de RIP140 est associée à un effet anti-prolifératif à travers une régulation positive de l'expression du gène p21WAF1/CIP1. Nous avons également démontré que RIP140 réduit la migration des cellules MKN45 et MKN74 et augmente l'expression du gène E-cadhérine au niveau transcriptionnel. D’une manière intéressante, nos résultats suggèrent aussi que RIP140 régule la voie de signalisation Hippo à travers l’activation de TEAD.Dans l'ensemble, ces résultats suggèrent que les gènes RIP140 et LCoR participent à la régulation de la tumorigenèse gastro-intestinale et que leurs niveaux d'expression ont une valeur pronostique dans ces cancers et pourraient servir de nouveaux biomarqueurs dans la caractérisation moléculaire de ces tumeurs. / Gastrointestinal cancers, particularly colorectal cancer (CRC) and gastric cancer (GC), are aggressive pathologies with a high mortality rate worldwide. These cancers are characterized by the deregulation of cellular signaling pathways such as the Wnt, Notch and Hippo pathways which play a very important role in gastrointestinal tumorigenesis. Moreover, it’s well established that the activity of the transcriptionnel factors involved in these nuclear signaling pathways is controlled by many transcriptionnel coregulators. This work focused on two transcriptional coregulators initially identified as partners of nuclear receptors, namely RIP140 and LCoR. The objective was to explore the expression of these two transcription factors in gastrointestinal cancers and their role in gastric cancers mainly through the dialogue with the Hippo signaling pathway.Immunohistochemical analysis of RIP140 and LCoR expression in colorectal and gastric cancers showed that the expression levels of these two transcriptional regulators are strongly correlated. In CRCs, their expression tends to decrease in tumor tissue compared to adjacent normal tissue, whereas in GCs, RIP140 and LCoR expression levels are significantly higher in the tumor as compared to normal stomach. Significant correlations were observed with clinicopathological parameters (TNM stage and tumor differentiation) as well as the expression levels of key proteins involved in tumor progression and invasion (E-cadherin and Cox-2). Survival analysis showed that CRC patients with LCoRlow/RIP140high tumors have a significant prolonged OS and DFS. In GC, high RIP140 or LCoR expression was identified as an independent marker of poor prognosis suggesting a key role in this malignancy.Further, we investigated the role of RIP140 in gastric cancer cell lines using human epithelial GC cell lines overexpressing or not RIP140. In both MKN45 and MKN74 cells we showed that RIP140 exerted an anti-proliferative effect through the induction of p21WAF1/CIP1 gene expression. We also demonstrated that RIP140 reduced GC cell migration and increased E-cadherin expression at the transcriptional level. Interestingly, our results also suggest that RIP140 regulates the Hippo signaling pathway through TEAD activation.In conclusion, our findings suggest that RIP140 and LCoR genes contribute to the regulation of gastrointestinal cancers and that their expression levels have a prognostic value in these pathologies. Moreover, both RIP140 and LCoR transcriptional coregulaters could serve as novel biomarkers in the molecular characterization of colorectal and gastric cancers.

Orientadores: Sophie Françoise Mauricette Derchain, Luis Otavio Zanatta Sarian / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-08T23:10:57Z (GMT). No. of bitstreams: 1 Bastos_JoanaFroesBraganca_D.pdf: 1852084 bytes, checksum: 0197c5b05094e118039dc4b6c6ffbf73 (MD5) Previous issue date: 2007 / Resumo: Objetivo: Avaliar a relação da expressão do p53 e do p16INK4a em diferentes graus de neoplasia intra-epitelial cervical (NIC) e suas possíveis relações com a recidiva/persistência da NIC após conização diatérmica e a infecção persistente de papilomavírus humano (HPV) de alto risco oncogênico. Sujeitos e métodos: Este foi um estudo de corte, com análise intermediária em corte transversal, para o qual foram selecionadas mulheres submetidas à conização diatérmica no período de fevereiro de 2001 a abril de 2004. Os resultados deste estudo são apresentados em dois artigos: o primeiro consiste em corte transversal incluindo 125 espécimes cirúrgicos de mulheres submetidas a conização diatérmica. Foram avaliadas a expressão do p53 e do p16INK4a em diferentes graus de NIC e sua relação com a infecção pelo HPV de alto risco oncogênico realizado através da Captura de Híbridos 2 (CH2). No segundo artigo, com análise longitudinal foram incluídas 104 mulheres com NIC 2 ou 3, seguidas por até 24 meses após conização diatérmica. Foram avaliadas a expressão de p16INK4a e p53 como fatores préditivos de persistência/recidiva de NIC e a sua relação com a infecção persistente por HPV de alto risco oncogênico após o conização cervical diatérmica. Resultados: No primeiro artigo foram incluídos 21 casos cervicites/NIC1, 17 NIC2 e 87 NIC3. Noventa e nove (79,2%) casos foram positivos para p16INK4a (> 5% do epitélio corado), significativamente maior em lesões de alto grau (p< 0.001). A expressão do p53 não variou de acordo com o grau histológico. Não houve correlação entre a expressão da p16INK4a e a detecção do HPV de alto risco oncogênico. A expressão do p16INK4a não teve relação com a do p53. No segundo artigo, 104 mulheres com NIC 2 ou 3 foram acompanhadas por 24 meses, e detectou-se 12 casos de recidiva/persistência de NIC, sendo 8 nos primeiros 6 meses. Entre as mulheres com recidiva/persistência de NIC, 9 (75%) apresentaram presistência do HPV de alto risco oncogênico. A expressão da p16INK4a foi moderada/forte em 96 casos (92%) e mais de 50% dos núcleos estavam corados para p53 em 80 (78%). A análise prospectiva não detectou diferença significativa na recidiva/persistência da NIC durante o follow up com segundo a expressão do p16INK4a ou do p53. Nenhum dos parametros estudados teve relação com a infecção persistente pelo HPV. Conclusões: este estudo está em concordância com o conhecimento atual e mostra uma associação da positividade para p16INK4a com a severidade da lesão cervical, embora esta proteína não esteja associada com a detecção de HPV de alto risco oncogênico pela CH2. Não houve correlação entre a expressão de p53 e a positividade para HPV nem houve associação da expressão do p53 com a do p16INK4a. A análise prospectiva não mostrou correlação entre a expressão do p 16 INK4a e do p53 e a recorrência/persistência da NIC ou persistência do HPV de alto risco oncogênico no seguimento de mulheres com NIC 2 ou 3 tratadas com conização diatérmica / Abstract: Objective: to concurrently investigate the immunoexpression of p53 and p16INK4a4 in different grades of cervical intra-epithelial neoplasia (CIN) and their relation with the persistence/ recurrence of CIN and persistent infection by high-risk Human Papillomavirus (hr-HPV) after electrosurgical cervical conization. Subject and methods: a series of 125 women subjected to electrosurgical conization was selected for this cross-sectional and cohort study. Enrollment was carried out between February 2001 and April 2004. The results of this study are presented in two articles: the first one consists of a cross-sectional analisys, including 125 surgical specimens of women who underwent diathermic conization. Expression of p53 and p16INK4a were evaluated in different grades of CIN and their relation with hr-HPV infection was evaluated with HC2. The second article is a longitudinal analysis on 104 women with CIN 2 and 3, followed up for 24 months after electrosurgical cervical conization. Expression of p16INK4a and p53 were tested as predictive markers of persistent/recurrent CIN and persistent infection by hr-HPV during follow up after electrosurgical cervical conization. Results: in the first series, 21 cases of CIN1, 17 CIN2 and 87 CIN3 were included. Ninety-nine (79.2%) cases stained moderate/strongly to p16INK4a, significantly higher in high-grade CIN (p< 0.001). p53 expression did not relate with the grade of CIN and there was no relation between p16INK4a expression and hr-HPV detection. Expression p16INK4a and p53 were not correlated. In the second article, 104 women with CIN 2 or 3 were followed up for 24 months, and 12 (11%) persistent/recurrent CIN were observed, eight of them during the first 6 months follow-up. Among women with persistent/recurrent CIN, 9 (75%) presented persistent hr-HPV detection. p16INK4a expression was moderate/strong in 96 cases (92%) and p53 stained in more than 50% of the nuclei in 80 (77%). The expression of p16INK4a or p53 was not associated with persistent/recurrent CIN during follow-up. None of the studied parameters correlated with persistent hr-HPV detection. Conclusion: these results showed a strong association between p16INK4a expression and grade of CIN, although this protein was not associated with hr-HPV detection by HC2. There was no relation between p53 and hr-HPV detection or p16INK4a expression. Prospective analysis showed that p16INK4a and p53 expression was not related with persistent/recurrent CIN or persistent hr- HPV detection during follow-up of women conservatively treated for CIN 2 or 3 / Doutorado / Tocoginecologia / Doutor em Tocoginecologia

Le carbure de silicium (SiC) nanostructuré est considéré aujourd'hui comme une bonne alternative aux matériaux traditionnels pour diverses applications multidisciplinaires. Dans cette thèse, des nanostructures de SiC ont été élaborées par gravure électrochimique et par ablation laser. La première partie de cette thèse décrit et explique la dépendance en taille des propriétés optiques ainsi que l'importance des effets de champ local sur les transitions électroniques photo-induites des nanostructures de SiC. Dans la seconde partie, il est démontré une amplification d’un facteur 15 de l’intensité de photoluminescence des nanoparticules de SiC par leurs interactions en champ proche avec les plasmons multipolaires localisées. En outre, un facteur 287 et un facteur 72, induits par le couplage plasmonique, sont obtenus respectivement pour les signaux de luminescence à deux photons et de génération de seconde harmonique. Les principaux mécanismes physiques responsables des effets observés ont été décrits par des simulations de type différences finies dans le domaine temporel en trois dimensions. Enfin, l'effet de couplage de nanoparticules de SiC luminescentes à des nanostructures plasmoniques en structures planes est utilisé pour améliorer le marquage de cellules biologiques. Une perspective est ouverte sur la réalisation et les premières caractérisations de suspension colloïdales de nanohybrides plasmonique (Au@SiO2)SiC. / Nanostructured silicon carbide (SiC) is considered today as a good alternative to the conventional materials for various multidisciplinary applications. In this thesis, SiC nanostructures were elaborated by means of electrochemical etching and laser ablation techniques. The first part of the thesis clarifies size-dependence of optical properties as well as importance of local-field effects onto the photoinduced electronic transitions of SiC nanostructures. In the second part of the thesis strong 15-fold photoluminescence enhancement of SiC nanoparticles is ensured by their near-field interactions with multipolar localized plasmons. Further, 287-fold and 72-fold plasmon-induced enhancement factors of two-photon excited luminescence and second harmonic generation is achieved, respectively. The main physical mechanisms responsible for the observed effects were described by three-dimensional finite-difference time domain simulations. Finally, the coupling effect of luminescent SiC nanoparticles to plasmonic nanostructures is used in the enhanced labelling of biological cells on the planar structures. As a perspective, colloidal plasmonic (Au@SiO2)SiC nanohybrids were elaborated and characterized.

Abstract Lymphomas are a heterogeneous group of malignancies, which usually have a good prognosis and high cure rates. Lymphomas are sensitive to chemotherapy and radiotherapy, and many patients can be cured even after a relapse, resulting in a need for effective follow-up. However, the cost-benefit ratio of radiological imaging in predicting the forthcoming relapses is poor. Consequently, there is a need for biological prognostic and predictive markers to distinguish patients at the highest risk of relapse at the time of diagnosis or during follow-up. Despite rapid progress in lymphoma treatments, some patients still die from lymphoma. Thus, more data on the basic biological features of lymphomas are also needed. Gelatinases (MMP-2 and MMP-9) and their tissue inhibitors (TIMP-1 and TIMP-2) have been found to play a role in the progression of solid tumours. TP53 is a tumour suppressor gene, the mutations and protein over-expression of which have been demonstrated to be associated with survival in most cancer types. There is also some evidence that these proteins could have prognostic significance in lymphomas as well. In the present study, the tissue expression, plasma concentrations and clinical value of gelatinases and their tissue inhibitors were evaluated in lymphomas. 249 primary tissue samples from patients with Hodgkin, follicular, or diffuse large B-cell lymphoma were analysed for expression of gelatinases and/or their inhibitors using immunohistochemistry. In follicular lymphoma, p53 protein expression was also investigated. The plasma samples of 126 lymphoma patients and a control group of 44 healthy volunteers were collected and studied by ELISA. TIMP-1 expression correlated with bulky tumour and nodular sclerosis subtype of Hodgkin lymphoma. In follicular lymphoma, p53 over-expression was an independent adverse prognostic factor for survival and a predictor of histological transformation. Plasma MMP-2-TIMP-2 complex appeared to be a potential follow-up marker predicting the risk of relapse in lymphoma patients. Plasma levels of the MMP-2-TIMP-2 complex, proMMP-2, TIMP-2 and proMMP-2/TIMP-2 ratio were at abnormal levels both in patients with newly diagnosed lymphoma and those in remission compared to healthy controls. The clinical significance of these markers needs further studies.