Le cancer de la prostate est un enjeu de santé publique majeur au Canada où il constitue la troisième cause de décès liée au cancer. Bien que les premiers stades de la maladie puissent être traités efficacement, les stades plus avancés restent difficiles à soigner. Face à ce problème majeur, le présent projet de recherche s'est intéressé au potentiel thérapeutique des activateurs de FXR (CDCA et GW4064). Dans les cellules cancéreuses LAPC-4, nous avons mis en évidence leur capacité à 1) bloquer le cycle cellulaire en phase Gl grâce à la répression de gènes du cycle cellulaire; 2) provoquer l'apoptose caspase-dépendante et 3) réprimer la transcription du récepteur aux androgènes. Bien qu'ils augmentaient la prolifération dans une autre lignée cancéreuse (LNCaP), ils diminuaient l'effet pro-prolifératif des androgènes. Ces résultats méritent donc d'être approfondis afin de mieux cerner l'utilité des activateurs de FXR dans le traitement du cancer de la prostate.

Le facteur de transcription Androgen Induced-bZIP (AlbZIP) est un membre de la famille ATF/CREB, plus précisément de la sous-famille CREB3. Sa découverte remonte au début des années 2000 où sa régulation par les androgènes fut démontrée, de même que son expression abondante dans le tissu prostatique. À l'image des facteurs ATF/CREB, AlbZIP possède un domaine d'activation de la transcription en N-terminal, un domaine bZIP et un domaine transmembranaire lui permettant de s'ancrer dans la membrane du reticulum endoplasmique. La structure et la localisation d'AIbZIP suggèrent qu'il puisse être clivé par le mécanisme Regulated Intramembrane Proteolysis (RIP) un mécanisme de clivage auquel sont soumis des facteurs ATF/CREB tels qu'ATF6. Ce clivage survient suite à un stress du reticulum endoplasmique (RE) qui peut être causé par différents stimuli qui perturbent l'homéostasie du RE. Les travaux présentés dans cette thèse visent l'identification de la fonction d'AIbZIP dans le stress du reticulum endoplasmique des cellules prostatiques cancéreuses. Mes objectifs étaient de découvrir des stimuli capables d'induire son clivage et d'identifier et de caractériser ses cibles transcriptionnelles suite à sa translocation au noyau. J'ai d'abord modifié le système d'expression inductible RheoSwitch et j'ai caractérisé son effet sur les cellules prostatiques cancéreuses LNCaP. Ce système s'est avéré être un outil efficace puisqu'il n'affecte pas le phénotype des LNCaP et il a été essentiel à la réalisation des travaux sur AlbZIP. J'ai ensuite mis en évidence le clivage d'AIbZIP par des agents qui causent une diminution de la concentration calcique au RE. Le système RheoSwitch modifié a permis de produire des cellules exprimant une forme active recombinante d'AIbZIP qui ont servi à la réalisation de micropuces Affymetrix. Ces puces ont permis l'identification des gènes cibles d'AIbZIP tel que le facteur de transcription CREB3. AlbZIP active l'expression de CREB3 par le biais d'éléments de réponse similiares à ERSE et CRE situés dans le promoteur du gène. Lors du traitement des cellules LNCaP avec l'ionophore de calcium A23187, on observe successivement le clivage d'AIbZIP, l'induction de l'expression de CREB3 et son clivage, ce qui suggère une chronologie dans l'activation des deux facteurs. La réponse au stress débute donc avec la forme active d'AIbZIP, suivie d'une co-existence des formes nucléaires d'AIbZIP et CREB3 pour se terminer par la présence de CREB3. CREB3 est en mesure d'activer sa propre transcription. Le stress causé par A23187 est en mesure d'activer AlbZIP et CREB3 qui se trouvent alors seuls ou simultanément au noyau. Il est donc possible qu'ils partagent des cibles communes, tout en ayant leurs cibles uniques, ce qui devra être élucidé pour clarifier leurs rôles respectifs dans la réponse au stress des LNCaP.

Les propriétés de la matrice extracellulaire (MEC) incluant la rigidité et la composition sont modifiées avec la progression tumorale dans le cancer de la prostate (PCa). De plus, ces propriétés affectent le risque de métastase des tumeurs. Toutefois, l'évolution de la composition dans la MEC tumorale n'est toujours pas caractérisée. Ce manquement dans la théorie impacte l'efficacité des thérapies actuelles. Ainsi, ce projet a pour but de caractériser l'évolution de la composition de la matrice extracellulaire (MEC) tumorale et d'évaluer l'impact conjoint de la rigidité et la composition sur la réponse des cellules en fonction de leur potentiel invasif. La composition en collagène (COL) et en fibronectine (FN) de tissus prostatiques murins cancéreux a été analysée. De plus, la réponse cellulaire à des matrices de différentes rigidités et compositions en COL et FN a été quantifiée en utilisant des lignées cellulaires à potentiel invasif variable. L'expression protéique des intégrines de surface de ces lignées a aussi été étudiée. Nos résultats démontrent une augmentation de l'expression de COL dans les tissus possédant des microinvasions et un maintien du ratio COL/FN tissulaire à bas potentiel invasif. De plus, les cellules invasives et non-invasives ont des réponses cellulaires plus importantes en présence d'une matrice de COL ou de FN respectivement. Les cellules localement invasives ont un phénotype intermédiaire répondant aux deux types de matrice. Les cellules ont une amplification de leur réponse à la rigidité lorsqu'en présence de leur matrice de prédilection. De ce fait, ces résultats démontrent un impact conjoint des propriétés de la MEC sur la réponse cellulaire selon leur potentiel invasif. Toutefois, l'expression des intégrines de surface ne semble pas être la cause de cette réponse différentielle. Ainsi, il serait possible d'utiliser l'évolution des propriétés de la MEC caractérisées pour développer de nouvelles techniques de pronostic.

La curiethérapie, une forme spécialisée de traitement du cancer, consiste à placer des sources radioactives près ou directement dans la lésion cancéreuse. Un aspect crucial de cette thérapie est le calcul de la dose de radiation. Traditionnellement, ce calcul s'appuie sur un formalisme qui considère l'eau comme milieu de transport, ce qui ne tient pas suffisamment compte des variations dans la composition des tissus du patient et des effets d'atténuation entre sources pour la curiethérapie permanente à faible débit de dose (LDR pour low-dose rate). La méthode Monte Carlo (MC) est la référence pour les calculs de dose avancés en curiethérapie, offrant une solution à ces limites. Cependant, l'application pratique de la méthode MC dans la planification du traitement est limitée par son temps d'exécution relativement lent. Cette thèse explore le potentiel des méthodes d'apprentissage profond (DL pour deep learning) pour surmonter ce défi. Plus précisément, la faisabilité d'utiliser des algorithmes DL pour prédire rapidement et avec précision la distribution de dose volumétrique pour patients de cancer de la prostate traités par la curiethérapie LDR est étudiée. Premièrement, le logiciel TOPAS a été systématiquement validée pour les simulations MC en curiethérapie en comparant les résultats simulés avec les données de référence TG-186 publiées. Le spectre d'énergie d'émission de photons, l'air-kerma strength et la constante de débit de dose de la source générique $^{192}$Ir MBDCA-WG ont été extraits. Pour les calculs de dose, un estimateur de longueur de trajectoire a été validé. Les quatre cas de test du groupe de travail MBDCA-WG AAPM/ESTRO/ABG ont été évalués. Un cas de prostate, un cas palliatif de poumon et un cas de sein ont été simulés. L'air-kerma strength et la constante de débit de dose étaient respectivement à 0,3% et 0,01% des valeurs de référence. Pour tous les cas de test, 96,9% des voxels avaient des différences de dose locales dans une plage de ±1%, tandis que les différences de dose globales concernaient 99,9% des voxels dans une plage de ±0,1%. Les histogrammes dose-volume des cas cliniques étaient cohérents avec les données de référence. TOPAS offre un accès étendu à un code MC de pointe pour les simulations en curiethérapie. Deuxièmement, un modèle DL à source unique entraîné avec des simulations MC comme référence a été proposé pour prédire avec précision les distributions de dose dans le milieu (D$_\textup{M,M}$ pour dose to medium in medium) en curiethérapie prostatique LDR. Des connaissances antérieures ont été incluses dans le réseau sous forme de noyau r$^2$ lié à l'inverse de la dépendance de dose de premier ordre en curiethérapie. Les caractéristiques du modèle montraient une représentation anisotrope tenant compte des organes du patient et de leurs interfaces, de la position de la source et des régions de faible et haute dose. La métrique CTV D$_{90}$ prédite présentait une différence moyenne de -0,1% par rapport au calcul basé sur MC. La prédiction d'un volume D$_\textup{M,M}$ complet de 1,18 M de voxels se réalise en 1,8 ms. Le modèle DL proposé représente donc un algorithme de calcul extrêmement rapide et simplifié, intégrant des connaissances physiques préexistantes pertinentes à la curiethérapie. Ce modèle est conçu pour tenir compte des caractéristiques anisotropes d'une source de curiethérapie et de la composition spécifique des tissus du patient, garantissant une approche précise et adaptée des calculs de dose. Enfin, deux algorithmes DL prédictifs de dose à plusieurs sources ont été validés pour la curiethérapie prostatique LDR. Les données de référence prenaient en compte les effets d'atténuation entre les sources et une définition des matériaux basée sur les organes du patient. De plus, les incertitudes aléatoires (associées aux données d'entrée) et épistémiques (associées au modèle) des modèles DL ont été évaluées. Les résultats ont montré que la métrique D$_{90}$ de la prostate prédite présentait une différence de -0,64% et de 0,08% pour les modèles UNet et ResUNet TSE, respectivement. Les deux modèles DL prédisaient un volume de dose de 2,56 M de voxels (128×160×128) en 4 ms. L'incertitude dérivée est quantifiable et interprétable, mettant en évidence les régions où les modèles DL pourraient rencontrer des difficultés pour fournir des estimations précises de dose. L'analyse de l'incertitude est un outil précieux pour une évaluation approfondie, améliorant le processus d'évaluation des modèles de prédiction de dose. De plus, cette analyse fournit des informations critiques sur la performance du modèle, identifiant les domaines d'amélioration potentielle et garantissant une application plus fiable dans un contexte clinique. / Brachytherapy, a specialized form of cancer treatment, involves the placement of radioactive sources near or directly within the cancerous lesion. A critical aspect of this therapy is the calculation of radiation dose. Traditionally, this calculation relies on a water-based formalism, which does not adequately account for variations in patient tissue compositions and interseed effects in low-dose rate (LDR) brachytherapy. The Monte Carlo (MC) method is the gold standard for advanced dose calculations in brachytherapy, offering a solution to these limitations. However, the practical application of the MC method in treatment planning is hindered by its relatively slow execution time. This thesis explores the potential of deep learning (DL) methods to overcome this challenge. Specifically, it investigates the feasibility of using DL algorithms to accurately predict the volumetric dose distribution in LDR prostate brachytherapy patients, aiming to streamline the treatment planning process while maintaining the precision of dose calculations. Firstly, the TOPAS MC toolkit was systematically validated for brachytherapy simulations by comparing simulated results with published TG-186 reference data. The photon emission energy spectrum, the air-kerma strength, and the dose-rate constant of the MBDCA-WG generic $^{192}$Ir source were extracted. For dose calculations, a track-length estimator was implemented. The four Joint AAPM/ESTRO/ABG MBDCA-WG test cases were evaluated. A prostate, a palliative lung, and a breast case were simulated. The air-kerma strength and dose-rate constant were within 0.3% and 0.01% of the reference values, respectively. For all test cases, 96.9% of voxels had local dose differences within ±1%. On the other hand, the global dose difference histograms had 99.9% of voxels within ±0.1%. Dose-volume histograms of clinical cases were consistent with the reference data. Overall, TOPAS provides access to a state-of-the-art MC code for brachytherapy simulations. Secondly, a single-seed DL model trained with MC simulations as the gold standard was built to predict accurate single-seed dose to medium in medium (D$_\textup{M,M}$) distributions in LDR prostate brachytherapy. Existing knowledge was included in the network as an r$^2$ kernel related to the inverse of the first-order dose dependency in brachytherapy. DL model features showed an anisotropic representation that considered the patient organs and their interfaces, the source position, and the low- and high-dose regions. The predicted CTV D$_{90}$ metric had an average difference of -0.1% with respect to the MC-based calculation. The single-seed DL model takes 1.8 ms to predict a complete 3D D$_\textup{M,M}$ volume of 1.18 M voxels. The proposed DL model represents a streamlined and rapid computational engine, incorporating pre-existing physics knowledge pertinent to brachytherapy. This engine is designed to consider the anisotropic characteristics of a brachytherapy source and the specific composition of patient tissues, ensuring an accurate, fast, and tailored approach to dose calculations. Lastly, two multi-seed DL-based predictive dose algorithms were trained for LDR prostate brachytherapy. Ground truth data considered interseed effects and an organ-based material assignment. Additionally, the aleatoric (associated with the input data) and epistemic (associated with the model) uncertainties of the DL models were assessed. Results showed that the predicted prostate D$_{90}$ metric had a difference of -0.64% and 0.08% for the UNet and ResUNet TSE models, respectively. Both DL models predicted a 3D dose volume of 2.56 M voxels (128×160×128) in 4 ms. The derived uncertainty is quantifiable and interpretable, highlighting regions where DL models might face challenges in delivering precise dose estimations. The uncertainty analysis is a valuable tool for a thorough evaluation, enhancing the assessment process of the dose prediction models. This analysis provides critical insights into the model's performance, pinpointing areas for potential improvement and ensuring a more reliable application in clinical settings.

Prostate cancer (PCa) is the second most common cancer in men with more than 1 million new cases worldwide each year. While some of the genomic, genetic and molecular events characterizing PCa have been functionally associated with tumor onset, development and resistance to therapy, the meaning of many other molecular alterations remains poorly understood. Recent development of organoids technology and prostate organoid cultures has established an innovative and valuable model for the study of adult tissue homeostasis, physiology and disease. In this project we combined prostate organoids technology with genetic engineering and CLICK-chemistry coupled Mass Spectrometry approaches in order to better characterize molecular features of wild type and genetically engineered mouse prostate organoids modeling early steps of human prostate tumorigenesis. In details, by manipulating mPrOs to proxy ETS-related gene (ERG) precursor PIN/HGPIN lesions of human prostate, we identified possible novel pro-tumorigenic roles of ERG which unleashes cells proliferation from the tight control of growth stimuli, and, even more interesting, corrupts immune system components to escape immune surveillance. In conclusion, this project shows that coupling innovative biological systems and technological approaches can lead to significant improvements in the analysis and understanding of disease mechanisms.

Abstract Title: The Relationship between Perceived Personal Risk of getting Prostate cancer and Prostate-Specific Antigen (PSA) Screening Yeatoe G. McIntosh, MPH Candidate Advisor: Emmanuel Anum, MBChB, MPH, PHD Preceptor: Emmanuel Anum, MBChB, MPH, PHD Background: Prostate cancer is one of the most common cancer diagnoses in the United States. The American Cancer Society estimates that in 2008 28,660 deaths would be attributed to prostate cancer, projecting it to be the leading cause of cancer deaths in U.S. men. Despite the potential threat this cancer presents to men and the potential for improved disease outcomes from early detection, guidelines for screening for prostate cancer are varied, and disparities in screening prevalence exist. In addition, disparities in knowledge about prostate cancer screening and misconceptions about the disease seem widespread. The main purpose of this study was to determine the relationship between perceived personal risk of getting prostate cancer and prostate cancer screening with the Prostate-specific antigen (PSA) test. Methods: Data were collected from the 2003 Health Information National Trends Survey (HINTS). Overall, 1,815 men ages 35 and above were included in the sample after exclusion of men ages 18-34. Logistic regression analyses were conducted to assess the association between perceived personal risk and prostate cancer screening with PSA test, while testing for interaction and further adjusting for possible confounders. A reduced model, in which variables with non-significant Wald chi-squared statistic had been excluded, was compared to the full model to access the change in parameter estimates. Using the model-based approach, we compared models with interaction terms to the one without interaction terms using the likelihood ratio test. Parameter estimates from the best fitting model were reported using the design-based method. SAS version 9.1 statistical software was used for analyses. Results: Among men ages 35-49, those who perceived their risk as high, were significantly less likely to screen than those who perceived their risk as low (OR: 0.20 95% CI: 0.05-0.78). Within ages 50-64 and 65 and above, there were no significant differences between perceived risk levels and PSA testing. Men, who did receive healthcare provider recommendation for screening, were more likely to obtain prostate cancer (PSA) screening than men who did not receive such recommendation (OR: 92.56 95% CI 36.56, 234.36). Conclusions: The relationship between perceived personal risk of getting prostate cancer and PSA screening is modified by age. As men aged, their odds of screening increased. The most significant predictor of PSA screening was health provider recommendation. PSA screening showed no association with either race or household income.

Prostate cancer is the most common form of non-skin cancer and the second leading cause of cancer deaths within the United States. The five year survival rate has increased from 69% to 99% over the last 25 years for the local and regional disease, but has remained fairly low (approximately 34%) for the advanced disease. Therefore, current research is aimed at finding complementary or alternative treatments that will specifically target components of the signal transduction, cell-cycle and apoptosis pathways to induce cell death, with little or no toxic side effects to the patient. In this study we investigated the effect of genistein on expression levels of genes involved in these pathways. Genistein is a (4 , 5 , 7-trihydroxyisoflavone) is a major isoflavone constituent of soy that has been shown to inhibit growth proliferation and induce apoptosis in cancer cells. The mechanism of genistein-induced cell death and potential molecular targets for genistein in LNCaP prostate cancer c ells was investigated using several techniques. The chemosensitivity of genistein towards the prostate cancer cells was investigated using the ATP and MTS assays and apoptosis induction was determined using apoptosis and caspase assays. Several molecular targets were also identified using cDNA microarray and RT-PCR analysis. Our results revealed that genistein induces cell death in a time and dose-dependent manner and regulates expression levels of several genes involved in carcinogenesis and immunogenicity. Several cell cycle genes were down-regulated, including the mitotic kinesins, cyclins and cyclin dependent kinases, indicating that genistein is able to halt cell cycle progression through the regulation of genes involved in this process. / Several members of the Bcl-2 family which are involved in apoptosis were also affected and a number of genes involved in immunogenicity were up-regulated including the DefB1 and HLA membrane receptors. The results of this study provide evidence of genistein's ability to inhibit growth proliferation and induce apoptosis and indicates its potential as an adjuvant in chemotherapy and immunotherapy. / by Kendra Merchant. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Made available in DSpace on 2016-03-22T17:26:57Z (GMT). No. of bitstreams: 1 Neivo.pdf: 343535 bytes, checksum: e65c41380c8ceabe9bc780ffcc1c99f1 (MD5) Previous issue date: 2005-02-14 / Objective: The objective of this study is to describe the reproducibility of the sentinel lymph node technique in patients with prostate cancer and verify if there is improved accuracy over modified lymphadenectomy. Material and methods: Twenty-three patients with biopsy proven prostate cancer were enrolled in this study. Lymphoscintigraphy was performed after the transrectal administration of 99mTc-Sulphur Colloid guided by ultrasound, with one injection in each prostate lobe. Images were obtained 15 and 180 minutes after injection. Sentinel lymph node was harvested during surgery using a gamma probe, followed by extended lymphadenectomy. Results: The mean age of the patients in this study was 66 years old. An average of 3.36 sentinel lymph nodes was found for each patient. Radioactive lymph nodes were identified by the gamma probe in 21 out of 23 patients. In one of the patients there was no radiopharmaceutical migration from the injection site and in another the sentinel lymph node was visualized by lymphoscintigraphy but was not found during surgery. Three patients had lymph node metastasis; in one of these patients the sentinel lymph node was the only positive node and was found outside the modified lymphadenectomy region (dissection of the lymph nodes from the obturator fossa and the external iliac). Conclusion: Sentinel lymph node biopsy in prostate cancer adds important information to the staging of patients, not always attained through the lymphadenectomy restricted to the obturator fossa and external iliac. Such information is essencial for the choice of the best treatment to be applied. / n

Prostate cancer is the most commonly occurring cancer and the second leading cause of cancer death for men in the United States. Because early prostate cancer is frequently without symptoms and data on how to prevent prostate cancer is lacking, early detection has the greatest potential for decreasing mortality. Studies have shown Hispanics/Latinos to be less likely than whites or African-Americans to utilize prostate cancer screening exams. The purpose of this descriptive study was to design a social marketing plan which could be used as a model to promote Hispanic/Latino participation at prostate cancer screenings. Information obtained through medical and marketing literature review, the author's experiences serving on the promotion committee of a community-sponsored prostate cancer screening project, and interviews with 51 Hispanic/Latino prostate cancer screening participants is described and incorporated into a guide with recommendations for future program planners.

Androgens are critical for the development and maintenance of adult male characteristics such as muscle mass and sexual function. Consequently, the established decline with age of serum testosterone (T) in males has major health implications. While the androgen receptor (AR) is the major mediator of genomic androgen action and is required for the development of the male phenotype, reproductive organs and the maintenance of male secondary sexual characteristics, it is the entrance of androgens into the cell that mediates the activation of the AR and the subsequent modulation of expression of androgen regulated genes. Testosterone, biologically the most important androgen in male serum, circulates either free, loosely bound to albumin or tightly bound to sex hormone binding globulin (SHBG). Each of these forms of serum T have different abilities to enter cells, and which proportion of serum T is capable of entering cells and initiating the androgen signalling cascade, thereby leading to the activation of the AR has not been precisely defined. The AR amino terminal domain (NTD) is responsible for the majority of the ability of the AR to activate genes but the relative roles of the two activation functions in the AR NTD (activation functions 1 and 5; AF1 and 5) have not been precisely defined while the role of the AF2 surface which forms in the ligand binding domain upon agonist binding is responsible for interactions with key coregulators and also with the NTD in the amino-carboxyl (N/C) interaction. Our laboratory has recently identified a region within AF5 between amino acids 500-535 to which somatic mutations in castrate resistant prostate tumour samples collocate. Due to the lack of functional information on the AF5 region and the NTD in general, the function of this region and the functional consequences of the mutations remain to be defined. The objectives of this thesis were to develop a specific mammalian cell based bioassay capable of reliable measuring T in serum and to determine the ability of this bioassay to measure a physiologically relevant fraction of T in serum. Additionally, this thesis aimed to determine the relative contributions and roles of the activation functions of the AR to overall AR transcriptional activity along with the functional consequences for AR signalling of prostate cancer mutations which have previously been identified in the AF5 region of the AR NTD. The mammalian-cell based bioassay developed in this thesis is capable of sensitively and reliably measuring serum T. However, evaluation of this bioassay utilising approximately 1000 serum samples from the Florey Adelaide Male Aging Study reveals that this bioassay measures a fraction of T in serum that most closely relates to serum T. Furthermore, this measure does not correlate more strongly with grip strength, sexual function or waist circumference than the existing immunoassay-based measures of serum T, highlighting the limitations of utilising a static mammalian cell-based androgen bioassay to measure physiological levels of serum T in males. The investigation of the roles of the activation functions in the AR in this thesis have revealed that while the AF1 domain is responsible for the majority of the transactivation activity of the AR, AF5 and AF2 govern the sensitivity and cellular response of the AR to androgens by providing protein and interdomain interaction interfaces. Furthermore, the evidence in this thesis demonstrates that the AR requires interdomain communication for sensitive AR signalling. Finally, the findings in this thesis demonstrate that the AF5 surface is required for the N/C interaction and coregulator interactions while advanced prostate cancer mutations identified within this region confer increased transactivation activity of the AR in the presence of high cellular levels of coregulators. Collectively, the findings in this thesis provide several novel insights into the mechanism of action of serum androgens and challenges several long held assumptions of androgenic action in males. These findings also delineate a mechanism of treatment failure in advanced prostate cancer, provide a novel model for the events leading to sensitive AR transactivation and contribute to the understanding of physiologically relevant levels of serum T. / Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2008