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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.
31

Μορφολογική εκτίμηση της έκφρασης του μεταγραφικού παράγοντα PPARγ και της συνομιλίας του (cross-talk) με το μεταγραφικό παράγοντα AP-1 κατά τη διαδικασία της καρκινογένεσης στα νεοπλάσματα εκ μεταβατικού επιθηλίου της ουροδόχου κύστης / Μorphological assessment of the expression of the transcriptional factor PPARγ and its cross-talk with the transcriptional factor AP-1 during the process of carcinogenesis in urothelial carcinomas

Πέττα, Ευρυδίκη 04 May 2011 (has links)
Ο καρκίνος της ουροδόχου κύστης είναι η τέταρτη συχνότερη κακοήθεια στους άνδρες και η δέκατη στις γυναίκες και η ετήσια επίπτωσή του αυξάνει συνεχώς στις ανεπτυγμένες χώρες. Oι προγνωστικοί παράγοντες που χρησιμοποιούνται σήμερα δεν μπορούν να προβλέψουν με βεβαιότητα την μακροπρόθεσμη έκβαση του ουροθηλιακού καρκίνου και έτσι προκύπτει η ανάγκη αναγνώρισης δεικτών με δυνατότητα πρόγνωσης της συμπεριφοράς των καρκινωμάτων. Επιπλέον, δεδομένων των περιορισμένων δυνατοτήτων των σημερινών θεραπευτικών επιλογών (χειρουργική αντιμετώπιση, χημειοθεραπεία ή ανοσοθεραπεία και ακτινοθεραπεία), απαιτούνται νέες θεραπευτικές στρατηγικές. Μία τέτοια στρατηγική είναι η στόχευση σε μεταγραφικούς παράγοντες όπως οι πυρηνικοί υποδοχείς και οι upstream ενεργοποιητές τους. Η διαταραχή αυτών των μεταγραφικών παραγόντων είναι κομβικό σημείο της έναρξης και διατήρησης του κακοήθους φαινοτύπου. O πυρηνικός υποδοχέας PPARγ εμπλέκεται στον έλεγχο του μεταβολισμού, την κυτταρική ανάπτυξη, την αγγειογένεση και την ανοσολογική και φλεγμονώδη απάντηση. Επιπρόσθετα, υπάρχουν ενδείξεις ότι ρυθμίζει τους μηχανισμούς καταστολής αλλά και προαγωγής της καρκινογένεσης. Ο RXRα είναι επίσης μέλος της υπεροικογένειας των πυρηνικών υποδοχέων και ετεροδιμερίζεται με τον PPARγ προς σχηματισμό του συμπλόκου που αλληλεπιδρά με το DNA. Οι προσδέτες των RXR υποδοχέων έχουν ήδη χρησιμοποιηθεί στη χημειοπρόληψη διαφόρων μορφών καρκίνου. Ο μεταγραφικός παράγoντας AP-1, απαρτίζεται από διμερή των Fos και Jun πρωτεϊνών και η δράση του σχετίζεται με την πρόοδο της καρκινογένεσης. Υπάρχουν πάντως και ενδείξεις για προ-αποπτωτική δράση του. Η CBP είναι ένας απ’ τους σημαντικότερους ολοκληρωτές σημάτων της μεταγραφής. Ο ανταγωνισμός μεταξύ των PPARγ και AP-1 για τη CBP είναι ένας απ’ τους μηχανισμούς που εξηγούν την αρνητική «συνομιλία» (cross-talk) μεταξύ των PPARγ και AP-1. Στην παρούσα μελέτη εξετάσαμε τόσο ξεχωριστά όσο και σε συνδυασμό μεταξύ τους, την έκφραση των πέντε μοριακών παραγόντων (PPARγ, RXRα, p-c-Jun, c-Fos, CBP) στο φυσιολογικό ουροθήλιο, τις προκαρκινικές αλλοιώσεις και τα ουροθηλιακά καρκινώματα (ΟΚ). Τα ιστικά δείγματα προήλθαν από 88 ασθενείς οι οποίοι υπέστησαν διαγνωστική βιοψία ή θεραπευτική κυστεκτομή, νεφρεκτομή ή ουρητηρεκτομή. Εφαρμόστηκε η ανοσοϊστοχημική μέθοδος σε τομές παραφίνης και εκτιμήθηκε η σχετική έκφραση των μελετώμενων παραγόντων στα ενδοκυττάρια διαμερίσματα, τις ενδοεπιθηλιακές στιβάδες και τις φυσιολογικές ή παθολογικές ιστολογικές βαθμίδες. Όλοι οι παράγοντες παρουσίασαν κυρίως πυρηνική εντόπιση. Η έκφραση του p-c-Jun ελαττώνεται στους ασθενείς άνω των 70 ετών σε σχέση με τους νεώτερους, ενώ κανένα άλλο απ’ τα μελετώμενα μόρια δε φαίνεται να επηρεάζεται από την ηλικία. Η έκφραση των PPARγ, CBP, p-c-Jun και c-Fos σημειώνει αύξηση κατά την πορεία προς τον καρκίνο. Όσο αφορά στα ΟΚ, οι PPARγ και CBP παρουσιάζουν αρνητική συσχέτιση με την αποδιαφοροποίηση. Επιπλέον ο PPARγ συσχετίζεται αρνητικά με την απόκτηση χαρακτήρων διήθησης στα ΟΚ. Αντιθέτως, η έκφραση του RXRα δεν διακυμαίνεται στατιστικώς σημαντικά σε όλη την πορεία της καρκινογένεσης. Η ανάλυση της συνδυασμένης έκφρασης των πέντε παραγόντων έγινε με σκοπό την αποκάλυψη ενδεχόμενων αλληλεπιδράσεων μεταξύ τους. Η προστατευτική δράση του PPARγ στο ουροθήλιο συνοδεύεται από ταυτόχρονη μέτρια ή ισχυρή έκφραση των RXRα, p-c-Jun και c-Fos. Αναλυτικά, η αυξανόμενη έκφραση του p-c-Jun συμπίπτει με ενίσχυση της θετικής συσχέτισης του PPARγ με καλύτερα διαφοροποιημένους, λιγότερο διηθητικούς όγκους, ενώ ο c-Fos φαίνεται να εξασθενίζει ήπια την ευνοϊκή δράση του PPARγ στη διαφοροποίηση του ουροθηλίου. Η αυξανόμενη έκφραση της CBP έδειξε να εξασθενίζει και τελικά να εκμηδενίζει τη στατιστικά σημαντική αύξηση του PPARγ στην πορεία προς τον καρκίνο και την επαγωγή του στους μη διηθητικούς όγκους σε σύγκριση με τους διηθητικούς. Ταυτόχρονα, η αρνητική σχέση της CBP με την αποδιαφοροποίηση και την αύξηση της κακοήθειας των ΟΚ επηρεάζεται από την παρουσία των PPARγ και AP-1, επιβεβαιώνοντας την υπόθεση της συνομιλίας αυτών των μοριακών παραγόντων. Ενδιαφέρουσα είναι η παρατήρηση ότι οι περισσότερες από τις αναφερθείσες πιο πάνω συσχτίσεις μεταξύ των μοριακών παραγόντων ίσχυαν για μεγαλύτερους των 70 ετών αλλά όχι πάντα για τους νεώτερους ασθενείς. Τα αποτελέσματα της παρούσας μελέτης μπορούν πιθανόν να οδηγήσουν σε συμπεράσματα με εφαρμογή σε χημειοπροληπτικές και θεραπευτικές στρατηγικές για τον ουροθηλιακό καρκίνο. / Bladder cancer is the fourth and tenth most common malignancy in men and women, respectively, and its incidence is increasing annually in the developed countries. Current prognostic parameters cannot predict with certainty the long-term outcome of bladder cancer and as a result there is a need to identify markers that may predict tumor behavior. Furthermore, given the limitations of current therapeutic options (surgery, chemotherapy or immunotherapy and radiotherapy), novel treatment strategies are very much needed. One such strategy targets transcription factors such as nuclear receptors and their upstream activators. Disruption of these transcription factors is a key element in the initiation and maintenance of a malignant phenotype. The nuclear receptor PPARγ is involved in controlling metabolism, cell growth, angiogenesis, and immune and inflammatory responses. In addition, it has also been suggested that it regulates tumor suppression as well as tumor promotion. RXRα is another member of the nuclear receptor superfamily, that partners PPARγ to form the DNA-binding complex. RXR ligands are already being used as chemopreventive agents in various types of cancer. The transcription factor AP-1 is formed by dimerization of Jun and Fos proteins and its activity is often associated with tumor progression. On the other hand, there is also evidence that AP-1 may enhance apoptosis. CBP is one of the most important transcriptional integrators. The competition of PPARγ and AP-1 for CBP is one of the multiple mechanisms that explain the negative PPARγ/AP-1 cross-talk. In the present study, we assessed separate and concurrent expression of the five factors (PPARγ, RXRα, p-c-Jun, c-Fos, CBP) in normal urothelium, precancerous lesions and urothelial carcinomas (UC). Clinical samples were derived from 88 patients who had undergone diagnostic biopsy or therapeutic excision of the bladder, the kidney or the ureter. Parafin section immunohistochemistry was utilized and relative expression was estimated in intracellular compartments, intraepithelial layers and histologic categories of urothelium. All five factors had mainly nuclear pattern of expression. P-c-jun was downregulated in patients older than 70 years old compared to younger ones, whereas age did not affect the expression of the rest four factors. PPARγ, CBP, p-c-Jun and c-Fos were upregulated towards tumorigenesis. PPARγ and CBP showed an inverse relationship with carcinoma level of differentiation. Moreover, PPARγ expression downregulated significantly in invasive tumors compared to non-invasive ones. On the contrary, RXRα expression did not vary significantly along the carcinogenesis course. The following correlations were based on coexpression analysis to reveal molecular interactions between the five factors. The established protective effect of PPARγ on urothelium was accompanied by concomitant RXRα, p-c-Jun and c-Fos moderate or strong expression. In detail, p-c-Jun’s increasing expression strengthened the positive relation of PPARγ with better differentiated, less invasive tumors, whereas c-Fos seemed to mildly lessen PPARγ’s favourable effect in urothelium differentiation. Statistically significant PPARγ upregulation in malignant tissues compared to normal urothelium and in non-invasive tumors compared to invasive ones is suppressed and finally cancelled by CBP’s increasing expression. PPARγ and AP-1 seemed to influence the negative relation of CBP with loss of differentiation and increase of malignant potential in UC, an observation that denotes a cross-talk between these molecular factors. Interestingly, most of the aforementioned correlations were noticed in patients older than 70 years old, but not all of them were plausible in younger patients. The results from the present study could lead to conclusions possibly applicable in chemoprevention and therapy strategies for urothelial carcinomas.
32

Comparação dos efeitos do diuron formulado e técnico no urotélio e nos parâmetros reprodutivos de ratos wistar machos / Comparison of formulated and technical diuron effects on the urothelium and reproductive parameters of male wistar rats

Sales, Bianca Camargo Penteado 22 February 2018 (has links)
Submitted by BIANCA CAMARGO PENTEADO SALES null (bianca.cp.sales@hotmail.com) on 2018-03-21T17:42:16Z No. of bitstreams: 1 Bianca C P Sales dissertação.pdf: 2161210 bytes, checksum: 81d8c087a65ae9b8745ff11c63af3b96 (MD5) / Approved for entry into archive by Luciana Pizzani null (luciana@btu.unesp.br) on 2018-03-22T14:23:56Z (GMT) No. of bitstreams: 1 sales_bcp_me_bot.pdf: 2161210 bytes, checksum: 81d8c087a65ae9b8745ff11c63af3b96 (MD5) / Made available in DSpace on 2018-03-22T14:23:56Z (GMT). No. of bitstreams: 1 sales_bcp_me_bot.pdf: 2161210 bytes, checksum: 81d8c087a65ae9b8745ff11c63af3b96 (MD5) Previous issue date: 2018-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Ratos Wistar expostos por dois anos ao diuron (3-(3,4-diclorofenil)-1,1-dimetilureia) produto técnico (PT) à 2500ppm pela ração desenvolveram alta incidência de tumores uroteliais, sendo esse herbicida classificado pela U.S. Environmental Protection Agency como "provável cancerígeno para o homem''. Durante a última década, nosso laboratório tem realizado estudos sobre a toxicidade urotelial do diuron PT fornecido pela ração a ratos Wistar machos. Porém, o diuron na forma de produto formulado (PF) ou comercial, composto por 50% de diuron PT e 50% de ingredientes inertes, não tem sido avaliado em ratos. Em lagartos P. sicula machos expostos ao diuron PF à 50% na concentração de 1100ppm na ração ou na água de beber, durante 3 semanas, houve toxicidade direta no sistema reprodutivo com alteração na espermatogênese, morfologia do epidídimo e diminuição dos níveis plasmáticos dos hormônios sexuais, sendo os efeitos mais severos nos grupos que receberam diuron na água de beber. O presente estudo objetivou comparar o potencial tóxico do diuron PF ou PT à 1250ppm oferecido pela ração ou água de beber no urotélio e nos parâmetros reprodutivos de ratos. Cinquenta ratos Wistar machos de seis semanas de idade foram distribuídos em cinco grupos (ração basal, ração com PF, água de beber com PF, ração com PT, água potável com PT) e expostos ao diuron à 1250ppm por 13 semanas. Na eutanásia foram avaliados a morfologia, concentração, motilidade e viabilidade dos espermatozoides. Os rins, fígado, baço, testículos e epidídimos foram retirados e pesados; os rins e testículos processados para histologia. A bexiga foi seccionada ao meio e processada para análise histológica e para microscopia eletrônica de varredura (MEV). Todos os grupos expostos ao diuron tiveram diminuição do peso corpóreo superior a 10%, comparados ao controle, indicando que a máxima dose tolerada (MDT) foi excedida. O consumo de ração e de água foi menor em todos os grupos expostos ao diuron. Não houve diferença nos pesos absolutos e relativos de órgãos entre os grupos. Em todos os grupos expostos ao diuron, os achados microscópicos incluíram hiperplasia urotelial simples (HS) na pelve renal e na bexiga à MEV. Diuron PF e PT induziram alterações na morfologia do esperma e diminuição da motilidade, concentração e viabilidade dos espermatozoides. Esse estudo mostrou que o diuron é nocivo ao urotélio e aos parâmetros reprodutivos de ratos Wistar machos, independentemente de estar na forma técnica (PT) ou formulada (PF) ou se administrado pela ração ou pela água de beber. / Wistar rats exposed during two years to 2500ppm dietary diuron technical product (TP) (3-(3,4- dichlorophenyl)-1,1-dimethylurea) developed high incidence of urothelial tumors, being classified by the U.S. Environmental Protection Agency as a ‘‘known/likely human carcinogen’’. During the last decades our laboratory conducted studies on the urothelial toxicity of the diuron (TP) provided through diet to male Wistar rats. The diuron formulated product (FP) composed by 50% diuron TP and 50% inert ingredients, has not been evaluated in rats. The diuron (FP) was harmful to reproductive system of male P. sicula lizards exposed to 1100ppm during 3 weeks; the toxic effects were more prominent in the groups receiving diuron FP in drinking water. This study aimed to compare the potential toxicity of diuron TP or FP 1250ppm offered through diet or drinking water on the urothelium and reproductive parameters of rats. Fifty six-week old Wistar male rats were allocated to five groups (basal diet, FP diet, FP drinking water, TP diet, TP drinking water) and exposed to 1250ppm diuron for 13 weeks. At the end, body weight and weight of kidneys, liver, spleen, testes and epididymis, histopathology of the kidneys and testes and sperm parameters were evaluated. Urinary bladders were bisected and processed for histologic and scanning electron microscopic (SEM) analyses. At the end of the study, all groups exposed to diuron had decreased body weight gain compared to control greater than 10%, indicating that for this experiment the dose exceeded the maximum tolerated dose (MTD). Food and drinking water consumption was lower in the groups exposed to diuron. There were no differences in the absolute and relative organ weights among the groups. In all groups exposed to diuron, microscopic findings included simple urothelial hyperplasia (SH) in the kidney pelvis and in the urinary bladder. By SEM, the urinary bladder had superficial cytotoxicity in all groups exposed to diuron. Diuron FP and TP induced changes in the sperm morphology and concentration, and decreased sperm motility and viability. This study showed that diuron FP as well as diuron TP is harmful to the urothelium and to the reproductive parameters of male Wistar rats, regardless of whether in a diet or drinking water.
33

Utilization of microRNA signatures as a diagnostic tool for canine urothelial carcinoma

Mara Suzann Varvil (16624251) 20 July 2023 (has links)
<p><em>Background:</em> UC is the most common urogenital cancer, comprising up to 2% of all naturally occurring neoplasia in dogs and can be challenging to diagnose. With early diagnosis, the disease can be controlled in most dogs with a good quality of life. MiRNAs are small non-coding RNAs that function by post-transcriptional regulation of gene expression. Their abundant presence and stability in the body make them promising tools for disease diagnosis. </p> <p><em>Hypothesis:</em> A microRNA (miRNA) signature can be used to differentiate canine urothelial carcinoma (UC) from other lower urinary tract diseases.</p> <p><em>Literature review:</em> There is an overlap of miRNA expression changes between normal physiologic processes, non-infectious and non-inflammatory conditions, infectious and/or inflammatory conditions, and neoplasia. Additionally, the mechanism of action of these overlapping miRNAs varies depending on the disease process. There is a lack of standardization of miRNA evaluation and consistency within a single evaluation method. Herein we evaluate three papers on miRNA expression in canine UC and compared the reported expression profile to human UC literature and identified experimentally validated targets of the dysregulated miRNA. </p> <p><em>Methods and results:</em> <strong>(Aim 1)</strong> Using reverse transcriptase quantitative PCR (RT-qPCR), we assessed the effects of sample handling on miRNA expression in formalin-fixed Paraffin-embedded (FFPE) tissue and urine sediment. We showed that the time of tissue fixation in formalin does not alter the detection of miRNA expression, but the inclusion of the muscularis layer altered the miRNA expression profile in bladder tissue. Additionally, miRNAs in urine sediment were proven to be stable despite the storage temperature for up to two weeks. <strong>(Aim 2)</strong> Using Next Generation Sequencing (NGS) with validation of findings via RT-qPCR, we evaluated differential miRNA expression in bladder tissue collected from normal canine urothelium and the invasive type of UC (iUC) to elucidate the dysregulated pathways. We found that twenty-eight miRNAs were differentially expressed (DE). The DE miRNAs were most often associated with gene silencing by miRNA, miRNAs in cancer, and miRNAs involved in DNA damage responses. Proteins involved include HRAS, KRAS, ARAF, RAF1, MAPK1, MAP2K1, MAPK3, FGFR3, EGFR, HBEGF, RASSF1, E2F2, E2F3, ERBB2, SRC, MMP1, and UP3KA. <strong>(Aim 3)</strong> Using RT-qPCR, expression of miR-214, miR-181a, miR-361, and miR-145 were evaluated. We failed to reject the null hypothesis that the relative gene expression in all groups was the same for any miRNA, nor did we find any multivariate summary that could effectively differentiate UC from inflammatory and non-neoplastic transitional cells. </p> <p><em>Conclusions:</em>   The findings within this thesis highlight the need for standardized methods for miRNA evaluation, support the use of stored samples for miRNA expression analysis, and show the importance of isolating the tissue of interest in FFPE. We defined the miRNome of iUC and investigated numerous protein pathways affected by dysregulation of differentially expressed miRNA in urothelial carcinoma. While we failed to reject our null hypothesis that the miRNA signature we evaluated could be utilized as a diagnostic tool for canine urothelial carcinoma, we showed the promise of miRNA as diagnostic tools and highlight several novel pathways that miRNA regulation affects in this disease. </p>
34

An orthotopic xenograft model for high-risk non-muscle invasive bladder cancer in mice: influence of mouse strain, tumor cell count, dwell time and bladder pretreatment

Hübner, Doreen, Rieger, Christiane, Bergmann, Ralf, Ullrich, Martin, Meister, Sebastian, Toma, Marieta, Wiedemuth, Ralf, Temme, Achim, Novotny, Vladimir, Wirth, Manfred, Bachmann, Michael, Pietzsch, Jens, Fuessel, Susanne 05 June 2018 (has links) (PDF)
Background Novel theranostic options for high-risk non-muscle invasive bladder cancer are urgently needed. This requires a thorough evaluation of experimental approaches in animal models best possibly reflecting human disease before entering clinical studies. Although several bladder cancer xenograft models were used in the literature, the establishment of an orthotopic bladder cancer model in mice remains challenging. Methods Luciferase-transduced UM-UC-3LUCK1 bladder cancer cells were instilled transurethrally via 24G permanent venous catheters into athymic NMRI and BALB/c nude mice as well as into SCID-beige mice. Besides the mouse strain, the pretreatment of the bladder wall (trypsin or poly-L-lysine), tumor cell count (0.5 × 106–5.0 × 106) and tumor cell dwell time in the murine bladder (30 min – 2 h) were varied. Tumors were morphologically and functionally visualized using bioluminescence imaging (BLI), magnetic resonance imaging (MRI), and positron emission tomography (PET). Results Immunodeficiency of the mouse strains was the most important factor influencing cancer cell engraftment, whereas modifying cell count and instillation time allowed fine-tuning of the BLI signal start and duration – both representing the possible treatment period for the evaluation of new therapeutics. Best orthotopic tumor growth was achieved by transurethral instillation of 1.0 × 106 UM-UC-3LUCK1 bladder cancer cells into SCID-beige mice for 2 h after bladder pretreatment with poly-L-lysine. A pilot PET experiment using 68Ga-cetuximab as transurethrally administered radiotracer revealed functional expression of epidermal growth factor receptor as representative molecular characteristic of engrafted cancer cells in the bladder. Conclusions With the optimized protocol in SCID-beige mice an applicable and reliable model of high-risk non-muscle invasive bladder cancer for the development of novel theranostic approaches was established.
35

An orthotopic xenograft model for high-risk non-muscle invasive bladder cancer in mice: influence of mouse strain, tumor cell count, dwell time and bladder pretreatment

Hübner, Doreen, Rieger, Christiane, Bergmann, Ralf, Ullrich, Martin, Meister, Sebastian, Toma, Marieta, Wiedemuth, Ralf, Temme, Achim, Novotny, Vladimir, Wirth, Manfred, Bachmann, Michael, Pietzsch, Jens, Fuessel, Susanne 05 June 2018 (has links)
Background Novel theranostic options for high-risk non-muscle invasive bladder cancer are urgently needed. This requires a thorough evaluation of experimental approaches in animal models best possibly reflecting human disease before entering clinical studies. Although several bladder cancer xenograft models were used in the literature, the establishment of an orthotopic bladder cancer model in mice remains challenging. Methods Luciferase-transduced UM-UC-3LUCK1 bladder cancer cells were instilled transurethrally via 24G permanent venous catheters into athymic NMRI and BALB/c nude mice as well as into SCID-beige mice. Besides the mouse strain, the pretreatment of the bladder wall (trypsin or poly-L-lysine), tumor cell count (0.5 × 106–5.0 × 106) and tumor cell dwell time in the murine bladder (30 min – 2 h) were varied. Tumors were morphologically and functionally visualized using bioluminescence imaging (BLI), magnetic resonance imaging (MRI), and positron emission tomography (PET). Results Immunodeficiency of the mouse strains was the most important factor influencing cancer cell engraftment, whereas modifying cell count and instillation time allowed fine-tuning of the BLI signal start and duration – both representing the possible treatment period for the evaluation of new therapeutics. Best orthotopic tumor growth was achieved by transurethral instillation of 1.0 × 106 UM-UC-3LUCK1 bladder cancer cells into SCID-beige mice for 2 h after bladder pretreatment with poly-L-lysine. A pilot PET experiment using 68Ga-cetuximab as transurethrally administered radiotracer revealed functional expression of epidermal growth factor receptor as representative molecular characteristic of engrafted cancer cells in the bladder. Conclusions With the optimized protocol in SCID-beige mice an applicable and reliable model of high-risk non-muscle invasive bladder cancer for the development of novel theranostic approaches was established.

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