The skeleton is the most common site of prostate cancer bone metastasis, and at present, there are no curable treatments for these patients. To further understand what stimulates tumor cell growth in the bone microenvironment and to find suitable therapies, reliable model systems are needed. For this purpose, we have developed an in vitro co-culture system that can be used to study interactions between tumor cells and murine calvarial bones. To validate the model, we measured the release of collagen fragments and monitored changes in expression levels of genes normally expressed during active bone remodeling. One of the major reasons why prostate cancer cells colonize bone is the abundance of tumor-stimulating factors, such as insulin-like growth factors (IGFs), present in this milieu. We found that the IGF-1 receptor (IGF-1R) was one of the most highly activated receptor tyrosine kinases in tumor cell lines stimulated with bone conditioned media. Since IGF-1 is known to be a strong survival factor for tumor cells, we hypothesized, that concurrent inhibition of IGF-1R signaling can enhance the effects of apoptosis-inducing therapies, such as castration. We used our co-culture model to target human prostate cancer cell lines, PC-3 and 22Rv1, with simvastatin (an inhibitor of the mevalonate pathway and an inducer of apoptosis), in combination with anti-IGF-1R therapy. Tumor cell viability declined with either one of the therapies used alone, and the effect was even more pronounced with the combined treatment. The hypothesis was also tested in rats that had been inoculated with rat prostate cancer cells, Dunning R3327-G, into the tibial bone, and treated with either anti-IGF-1R therapy, castration, or a combination of both therapies. Immunohistochemistry was used to evaluate therapeutic effects on tumor cell proliferation and apoptosis, as well as tumor cell effects on bone remodeling. The tumor cells were found to induce an osteoblastic response, both in vivo in rats, and in vitro using the co-culture model. Interestingly, the therapeutic response differed depending on whether tumor cells were located within the bone marrow cavity or if they had leaked out into the knee joint cavity, highlighting the role of the microenvironment on metastatic growth and therapeutic response. Therapies targeting the IGF-1R have been tested in clinical trials, unfortunately with disappointing results. By immunohistochemical evaluation of bone metastases from patients with castration-resistant prostate cancer, we found a large variance in IGF-1R staining within this group of patients. Hence, we postulate that the effects of anti-IGF-1R therapies could be more beneficial in patients with high tumoral IGF-1R-activity than in IGF-1R negative cases. We also believe that side effects, such as hyperglycemia, associated with anti-IGF-1R therapy, could be reduced if this treatment is administered only to selected patients and for shorter time periods. In a separate study, using whole-genome expression data from bone metastases obtained from prostate cancer patients, we present evidence that a high activity of osteoblasts is coupled to a high activity of osteoclast. Moreover, we found that high bone remodeling activity is inversely related to tumor cell androgen receptor (AR) activity. The results from this study may be of importance when selecting therapy for patients with bone metastatic cancer, especially when bone-targeting therapies are considered, and could aid in the search for novel therapeutic targets. In summary, we present an in vitro model for studies of the bidirectional interplay between prostate cancer cells and the bone microenvironment. We also demonstrate the importance of IGF-1 in prostate cancer bone metastases and suggest that inhibition of IGF-1R signaling can be used to treat prostate cancer as well as to enhance effects of other treatments such as androgen deprivation therapy. Furthermore, we emphasize the possibility of molecular tumor characterization when designing treatment plans for individual patients, thereby maximizing the therapeutic effects.

University of Macau / Faculty of Health Sciences

Pancreatic cancer is an aggressive disease with poor prognosis and a high fatality rate. Gemcitabine, the standard first-line chemotherapy for advanced disease, has negligible effects, necessitating the development of new therapies. We previously demonstrated that deletion of the anti-apoptotic gene E1B19K (AdΔ19K) in a replication-selective adenoviral mutant, caused synergistically-enhanced cell-killing when combined with low-dose DNA-damaging drugs in pancreatic cancer xenograft models. To delineate the cellular pathways targeted by the combination treatment we employed AdΔ19K and gemcitabine or irinotecan, with the goal of identifying cellular factors that are essential for the synergistic cell-killing. We hypothesised that AdΔ19K and DNA-damaging drugs act synergistically to deregulate cell-cycle mechanisms. Pancreatic cancer cell death induced by AdΔ19K and DNA-damaging drugs is apoptotic and time-dependent. AdΔ19K could not block DNA-damage responses (DDR) elicited by the drugs, despite virus-mediated degradation of the DDR factor Mre11. Mre11 siRNA-mediated knockdown augmented the synergistic cell death. Mitotic-index analysis in synchronised cells and immunofluorescence microscopy suggested that AdΔ19K promotes mitotic entry of gemcitabine-treated DNA-damaged cells. Moreover, AdΔ19K inhibited drug-induced accumulation of Claspin, a DDR protein whose degradation is required for checkpoint recovery. Treatment with AdΔ19K and gemcitabine accelerated Claspin degradation, and siRNA-mediated Claspin knockdown enhanced the synergistic cell death. Time-lapse microscopy in histoneH2B mCherry-expressing cells showed that AdΔ19K enhanced gemcitabine-induced mitotic catastrophe, characterised by prolonged mitosis, chromosome missegregation errors, cytokinesis failure and formation of multinucleated cells. Moreover, live-cell imaging revealed that the majority of cells treated with AdΔ19K and gemcitabine die before mitotic entry. 5 These findings suggest that E1B19K-deleted adenoviruses cannot prevent cell-cycle checkpoint responses elicited by DNA-damaging drugs, but enhance drug-induced cell death by downregulating DDR factors, such as Mre11 and Claspin. Additionally, the virus enhances mitotic catastrophe of DNA-damaged cells escaping cell-cycle checkpoints, eventually leading to increased apoptosis. Through these studies cellular pathways and factors involved in the synergistic cell killing were identified, that could be explored in the future to develop improved targeted therapies for pancreatic cancer.

The diagnostic pathway for prostate cancer involves the blood test prostate specific antigen (PSA) which has high sensitivity but low specificity at age related reference ranges. The resultant clinical consequence is a large number of negative diagnostic studies (transrectal ultrasound guided biopsies - TRUS). There is a need for a secondary screening test to help improve on the current diagnostic pathway. Mechanical markers have been used previously to assess the prostate for disease with numerous ex-vivo reports of differences between benign and malignant prostates. There have been no in-vivo studies with direct elasticity assessment devices for prostate cancer detection. This thesis forms part of work in a collaborative study in conjunction with engineers who have created a microscale device, capable of dynamic elasticity assessment. The specific objectives of this thesis were to a) assess dynamic micromechanical markers for the detection and differentiation of clinically significant from insignificant prostate cancer b) to identify relationships between mechanical and histopathological variables in the ex-vivo and in-vivo environments and c) assess the potential for these markers to differentiate peri-prostatic tissues. A prospective study was set-up with full ethics and management approvals with patients undergoing a systematic mechanical assessment of their prostate using the E-finger device and after prostate excision a systematic ex-vivo mechanical assessment on a calibrated stage. The ex-vivo assessment allowed accurate histopathological and mechanical variable assessment in a controlled environment. 7-Tesla ex-vivo MRI scanning aided in assessing the limitations of mechanical assessment of the prostate. There were clear consistent differences between individual dynamic micromechanical markers for benign and tumour containing measurement areas in both environments. Modelling of these dynamic micromechanical markers yielded encouraging accuracy levels for the detection of prostate cancer and differentiation of significant from insignificant disease. There were associations between individual mechanical markers and important histopathological features associated with cancer (acinar size, tumour volume and reactive stroma). These markers showed promise and utility in the differentiation of prostate from bladder and rhabdosphincter. This work demonstrates the clear potential translational uses for dynamic micromechanical markers in the assessment of the prostate for cancer.

Thesis (M Med. (Family Medicine))-- University of Limpopo, 2009. / Introduction Inspired by the late presentation for care and consequently the diagnosis of breast cancer done at an advanced stage of the disease in majority of cases, this study aimed to explore the knowledge and practices related to breast cancer from patients presenting at Princess Marina Hospital (PMH) for care. Methodology The descriptive qualitative method using interviews (free attitude) was chosen to understand the trend of late presentation among participants, with following opening questions: 1. Can you please tell me all you know about the cancer of the breast? 2. How have you been treating your breast condition (growth/wound/pain) before you decided to come to PMH? Sampling was purposeful with a sample of twelve. Out of eleven interviews done with breast cancer patients fulfilling the criteria of inclusion, ten were used in the final analysis. Interviews were recorded (audiotape), transcribed verbatim and translated. Emerging themes were identified and coded into different categories Results This study noted a poor knowledge and understanding of patients about cancer of the breast. The knowledge and practice of the common well established screening methods like self breast examination (SBE) was equally poor. In majority, participants delayed going to the hospital as a result of the preceding( poor knowledge and understanding about Ca breast ), as well as the influence of lays beliefs and advices received from the surrounding. In some cases however advices from the surrounding resulted in timely medical consultation. Unexpectedly, Poor clinical practice of health worker in some cases and decision maker‟s inadequate involvement on issue of cancer awareness were other important themes which emerged during analysis of the results. Conclusions Cancer awareness together with consistent use of early detection measures by adhering to screening methods should be taken seriously and done throughout the country for the benefit of all potential victims, to address the poor knowledge, misconceptions and inappropriate health seeking behavior encountered in case of breast cancer.

Thesis (MPH)--University of Limpopo, 2009. / Cervical cancer is the second highest form of cancer among women in Botswana, with breast cancer being the commonest (Ferlay et al, 2002), and is currently the highest cause of cancer deaths in Botswana (Ferlay et al, 2002). Cervical cancer screening using Pap smear provides an appropriate way for early detection and prevention of cervical cancer if appropriately implemented. Cervical cancer screening was introduced in Botswana in 2003 free of charge to all women of age greater than 18 years attending government hospitals. Despite this step by the government to decrease the mortality and morbidity rates resulting from cervical cancer, the uptake of cervical cancer has remained low among women in Botswana (Botswana central statistic report, 2009). Aim of the study; The study was aimed at identifying and describing factors influencing cervical cancer screening uptake among women greater than 18 years attending Mahalapye District Hospital in Botswana using the Health Belief Model. Methodology; This study was a cross sectional survey in which a questionnaire was used to interview 300 participants in order to assess their perceived susceptibility to cervical cancer, their perceived severity of cervical cancer, their perceived benefits of doing cervical cancer screening and their perceived barriers of seeking cervical cancer screening. Descriptive statistics was used to identify and describe factors influencing cervical cancer screening uptake among women attending Mahalapye District Hospital, Botswana using the Health Belief Model construct. Each question in the questionnaire was scored using a 5-point Likert scale ranged from strongly agree (5) to disagree (1). Negatively worded questions had their scales reversed and scores for each construct of the Health Belief Model was added to get an average. Analysis compared women who had ever had „cervical cancer screening‟ with women who had never had „cervical cancer screening‟. Chi-square statistic was used to test for association of selected variables and binary logistic regression was used to measure the associations for the aggregate score of health belief model constructs. Results; Cervical cancer screening rates was 39%. Participants were aware of the perceived severity of cervical cancer (average response 2.58-3.60), perceived benefits of cervical cancer 6 screening (average response 3.10-4.33) and perceived barriers to seeking cervical cancer screening (average response 2.0-3.44) but these were not significantly associated with screening. The highest predictor of cervical cancer screening was perceived susceptibility and those with high perceived susceptibility were 3.2 times more likely to do cervical cancer screening than those with low perceived susceptibility. Main socio-demographic characteristics significantly associated with perceived susceptibility were employment, monthly income and residential area while perceived severity was significantly associated with monthly income and residential area. Conclusions; Perceived susceptibility to cervical cancer was significantly associated with cervical cancer screening. Educational programs geared towards increasing perceived susceptibility to cervical cancer can significantly improve the uptake of cervical cancer screening in Botswana as well as address issues of barriers and misconceptions associated with low uptake of cervical cancer screening.

Thesis (Ph. D.)--University of Chicago, Committee on Immunology, August 1999. / Includes bibliographical references. Also available on the Internet.

Les chimiokines, petites protéines sécrétées par de nombreux types cellulaires, régulent le trafic et la fonction des populations leucocytaires en interagissant avec leurs récepteurs spécifiques, qui appartiennent à la superfamille des récepteurs à 7 domaines transmembranaires couplés aux protéines G. Dans le contexte tumoral, les chimiokines jouent des rôles ambivalents, en régulant le recrutement des leucocytes, ainsi que la croissance et l’angiogenèse des tumeurs. Aussi, les chimiokines semblent également contribuer à déterminer les sites métastatiques des tumeurs malignes. Notre travail porte sur l’étude du rôle de chimiokines et récepteurs, fréquemment exprimés au sein de tumeurs, dans un modèle tumoral chez la souris, la lignée cellulaire LLC (Lewis Lung Carcinoma). Chaque gène d’intérêt (CCR3, CCR6, CCR7, CXCR4, CXCR5, CCL19, CCL20, CCL21, CXCL13) a été exprimé dans la lignée LLC, ces différentes lignées ont été greffées à des souris syngéniques, et les caractéristiques phénotypiques des tumeurs ont été analysées, notamment la croissance tumorale, la fréquence et la distribution des métastases, et l’importance des réactions immunitaires de l’hôte. Nous avons montré que la croissance tumorale n’est pas affectée par l’expression des différents récepteurs étudiés, ni par celle des chimiokines CCL19 et CCL21, alors que l’expression de CXCL13 et de CCL20 par les cellules LLC réduit leur croissance in vivo. La quantification des métastases pulmonaires a montré que l’expression de CCR3, CXCR5, CCR7, CCL19 ou CCL21 par les cellules tumorales n’affecte pas significativement le potentiel métastatique des cellules LLC. Par contre, l’expression de CXCR4 entraîne une augmentation, et CCR6 une diminution, du nombre de métastases pulmonaires. La diminution du potentiel métastatique des tumeurs LLC/CCR6 implique notamment l’augmentation des propriétés d’adhésion de ces cellules. Les cellules LLC produisent naturellement de petites quantités du ligand CCL20. Nous postulons que la stimulation autocrine de CCR6 par CCL20 dans ces cellules in vivo augmente leurs propriétés d’adhésion et diminue leur potentiel métastatique. Dans le contexte de l’implication des chimiokines et récepteurs dans la détermination des sites métastatiques, nous proposons dès lors un modèle plus général : les récepteurs aux chimiokines dirigent les cellules tumorales vers les sites métastatiques où est produit le ligand correspondant ; cependant, si le ligand est produit au niveau de la tumeur, il favorise le maintien des cellules tumorales au niveau du site primaire. L’effet anti-tumoral de CCL20 ne dépend apparemment pas d’un recrutement plus important de cellules dendritiques, de lymphocytes T et de cellules NK exprimant le récepteur CCR6. Nos observations suggèrent plutôt un effet de CCL20 sur l’angiogenèse tumorale.

Selective receptor modulators have been developed for steroid hormone receptors as a new class of mechanism-based drugs for treatment of hormone related diseases. We investigated an alternative mechanism-based strategy for treating various cancers with selective aryl hydrocarbon receptor modulators (SAhRMs), such as diindolylmetane/(DIM), 2,3,7,8-tetrachlorodibenzo-pdioxin/( TCDD), and 6-6-methyl-1,3,8-trichlorodibenzofuran/(MCDF) that exhibit antiproliferative activity in several cancer cell lines. MDA-MB-453 and BT-474 are estrogen receptor/(ER) negative breast cancer cell lines that express a functional aryl hydrocarbon receptor/(AhR) and treatment with SAhRMs significantly inhibited MDA-MB-453/BT-474 cell proliferation but did not significantly affect the percent distribution of cells in G0/G1/S/G2/M phases of cell cycle. TCDD and the SAhRMs had minimal effects on the expression of various cellular kinases. These data coupled with results obtained for other activated kinase pathways demonstrate that TCDD and SAhRMs uniquely inhibit growth of ER-negative MDA-MB 453/BT-474 breast cancer cells through kinase independent pathways. However, the SAhRMs induced HES-1, an antiproliferative transcription factor, in both cell lines and this might represent a possible mechanism for the growth inhibitory effects observed with these compounds. We proved that ring substituted DIMs exhibit androgenic/antiandrogenic activities in androgen receptor/(AR)-positive LNCaP/22RV1 prostate cancer cell lines resulting in antiproliferative activities. These antiproliferative activities were accompanied by antiandrogenic activity and structure-dependent down regulation of AR. The ring-substituted DIMs also induced both non-steroidal anti-inflamatory drug-induced gene-1/(NAG-1) and activating transcription factor 3/(ATF-3), two anti-proliferative/apoptotic genes which are responsible in part for the inhibitory effects of these compounds on the proliferation of prostate cancer cells.

Thesis (MNutr)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.