Ethonafide is an anthracene-containing derivative of amonafide that belongs to the azonafide series of anticancer agents. The lack of cross-resistance in MDR-expressing cancer cell lines and the absence of a quinone and hydroquinone moiety make ethonafide a possible less-cardiotoxic replacement for existing anthracene-containing anticancer agents, such as mitoxantrone and doxorubicin. For this study, we investigated the anticancer activity and mechanism of action of ethonafide in human prostate cancer cell lines. Ethonafide was cytotoxic against three human prostate cancer cell lines at nanomolar concentrations. Ethonafide was also found to be better tolerated and more effective at inhibiting tumor growth compared to mitoxantrone in DU 145 prostate cancer-bearing mice. Mechanistically, we found that ethonafide inhibits topoisomerase II activity in human prostate cancer cell lines and equally inhibits purified topoisomerase IIα and recombinant topoisomerase IIβ. The inhibition of topoisomerase II activity was due to stabilization of the cleavable complex, involving both topoisomerase IIα and β. By creating stable DU 145 cell lines with decreased expression of either topoisomerase IIα or β, we found that topoisomerase IIα is necessary for ethonafide-induced cytotoxicity. The decrease in sensitivity to ethonafide was due to a decrease in DNA damage and an increase in DNA repair as measured by the neutral comet assay. Additionally, ethonafide induces potent G₂ cell cycle arrest in the DU 145 human prostate cancer cell line. Ethonafide also induces apoptosis as measured by procaspase and PARP cleavage. In conclusion, we have identified ethonafide as a topoisomerase II poison and determined that it is topoisomerase IIα-specific in the DU 145 human prostate cancer cell line. Due to ethonafide’s activity in vitro and in vivo, decreased toxicity in mice compared to mitoxantrone, and its activity in multi-drug resistant cancer cell lines, ethonafide may be a suitable replacement to mitoxantrone for the treatment of hormone-refractory prostate cancer.

Prostate cancer is the most common malignancy among men. The gold standard clinical diagnosis method for prostate cancer is histopathologic analysis of biopsy samples acquired under ultrasound guidance. However, most prostate tumors lack visually distinct appearances on medical images. Therefore, pathologically significant cases of cancer can be missed during biopsy, resulting in false negative or repeated trials. The goal of our research is to augment ultrasound-guided prostate biopsy by adding tissue typing information that can be used for targeted biopsies. As a new paradigm in tissue typing, we hypothesize and demonstrate that if a specific location in tissue undergoes sequential interactions with ultrasound, the time series of echoes, which we call radiofrequency (RF) time series, would carry ``tissue typing'' information. We provide a potential physical explanation for this phenomenon and justify it based on computer simulations of the ultrasound probe and scattering media. We also report laboratory and animal studies that illustrate the utility of the method. We rely on a set of seven spectral and fractal features extracted from RF time series for tissue typing. To show the clinical value of the proposed approach, we report an ex-vivo study involving 35 patients in which the utility of RF time series features for detection of prostate tumors is confirmed. The outcomes are validated using histopathologic disease distribution maps provided for the studied specimen. We show that the RF time series features are powerful tissue typing parameters that result in an area under receiver operating characteristic (ROC) curve of 0.87 in 10-fold cross validation for diagnosis of prostate cancer. They are significantly more accurate and sensitive than spectral features extracted from single RF frames, and also B-scan texture features (area under ROC curve of 0.78 and 0.72, respectively). A combination of these three categories of features results in a feature vector that provides an area under ROC curve of 0.95 in 10-fold cross-validation and 0.82 in leave-one-patient-out cross validation for diagnosis of prostate cancer. Using this hybrid feature vector and support vector machines, we create cancer distribution probability maps that highlight areas of tissue with high risk of cancer. / Thesis (Ph.D, Computing) -- Queen's University, 2008-09-27 07:51:11.45

Background: Quality of patient care includes both technical and non-technical elements of care, referred to as personal care. Previous work has focused on assessing the quality of technical care in prostate cancer radiotherapy, but little work has been done to assess the quality of personal care. Purpose: The purpose of this project was to create a self-administered questionnaire to measure the quality of personal care for patients undergoing radiotherapy for early-stage prostate cancer. Methods: Dimensions and candidate indicators of the quality of personal care were identified through a comprehensive literature search. The indicators were assigned to dimensions and then arranged into steps in the radiotherapy care continuum. A questionnaire was constructed using the indicators to assess patients’ views about the quality of their care as well as the importance of each indicator. Cognitive interviews were conducted with four health care professionals and eight patients to determine the clarity, comprehensiveness and appropriateness of the questionnaire. The questionnaire was then pilot tested on patients undergoing radiotherapy for early-stage prostate cancer. Results: A total of 176 indicators of the quality of personal care were initially identified representing 10 dimensions of care. Cognitive interviews identified problems with the questionnaire primarily related to the clarity and redundancy of the indicators and the appropriateness of the response categories. To reduce burden, the questionnaire was divided into three modules, corresponding to appropriate steps in the continuum of care. Each module was pilot tested on at least 10 patients with an overall response rate of 84%. Most patients responded to all indicators on the questionnaire without difficulty and without distress; however patterns of missing responses indicate a few particular indicators need revision. The results suggest that the design of the questionnaire is appropriate since patients seem to be using the range of response options that are offered. Conclusions: The results suggest that this questionnaire is feasible to administer in a clinic setting and that it does not place a large burden on patients. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2010-12-17 07:41:09.823

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / "The objectives of this thesis were to characterise the effects fo AR-targeting agents on the growth of prostate cancer cells and to determine whether combining these agents to target the AR (androgen receptor) at more than one level in the signalling pathway would provide a more complete block of androgen signalling and prostate cancer cell growth." --p. v. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1289482 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine,2006

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / "The objectives of this thesis were to characterise the effects fo AR-targeting agents on the growth of prostate cancer cells and to determine whether combining these agents to target the AR (androgen receptor) at more than one level in the signalling pathway would provide a more complete block of androgen signalling and prostate cancer cell growth." --p. v. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1289482 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine,2006

Thesis (Ph. D.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves vii, 276-309).

Thesis (Ph.D.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves vii, 276-309) Also available in print.

Prostate cancer is one of the most common cancers affecting one of every six men in United States. It is increasingly appreciated that tumor or cancer stem cells are the cells responsible for initiating tumor formation and therefore should be targeted for eradication in cancer treatment. But the mechanism involved in the acquisition of unlimited self-renewal and tumor initiation by cancer stem cells is unknown. Nanog, along with Oct3/4 and Sox-2, constitute the core transcriptional circuitry for the maintenance of stemness in embryonic stem cells. Herein we report that Nanog expression was detected at mRNA and protein levels in prostate cancer cells. The Nanog-expressing LNCaP-T and DU145 cells were enriched by infection with lentiviruses expressing GFP under the control of Nanog promoter. The Nanog-enriched prostate cancer cells had stronger expressions of stem and progenitor cell surface markers, including CD44 and CD133, when compared with those in the control group. Colony formation assay found that the Nanog-enriched LNCaP-T and DU145 cells formed more holoclones and prosta-spheres, which contained more self-renewing cells, than the control cells did. On the other hand, knockdown of Nanog in DU145 or LNCaP-T cells, via shRNAs, reduced their ability to form holoclones. Instead, most clones derived were meroclone and paraclones as result of increased differentiation and senescence due to knockdown of Nanog. When injected into mice, Nanog-enriched DU145 cells were found to possess increased tumorigenic potentials when compared to the vector controls. On the other hand, LNCaP-T cells with Nanog knocked down did not form tumors, while the vector controls readily formed tumors. Taken together, our data suggest an essential role for Nanog in the self-renewal and tumor initiation of prostate cancer cells. Chemotherapy is the major salvage therapeutic modality available for the patients with advanced cancers. However, drug resistance by some prostate cancer cells is a major barrier to efficacious chemotherapy. It has been increasingly appreciated that cancer stem cells are responsible for resistance to chemo- or radio-therapy, in addition to tumor initiation. However, the mechanisms involved remain unknown. In this study, we examined whether Nanog plays an essential role of Nanog in resistance to chemotherapy. In the surviving fractions of prostate cancer cells, we found increased levels of Nanog protein when compared to the cells treated with solvent control. To determine the role of Nanog in resistance of prostate cancer cells, we marked and enriched Nanog-expressing prostate cancer DU145 and LNCaP-T cells using a reporter gene under control of 2.5 kb hNanog1 promoter. When compared to the control, the prospectively enriched Nanog-expressing cells presented increased resistance to Taxol, vinblastine, and doxorubicin. Profiling of genes in drug resistance and metabolism revealed a marked increase in the mRNA level of ATP-binding cassette (ABC) efflux transporters B1 and G2 in tumor cells enriched with endogenous Nanog expression. The increased expression of ABCB1 and ABCG2 at protein levels in Nanog expressing cells was confirmed by Western blot and immunocytochemistry. Inhibition of ABCB1 activities sensitized Nanog expressing cells toward Taxol and vinblastine, and to less extent, doxorubicin. Blocking of ABCG2 activity sensitized Nanog expressing cells toward doxorubicin, but not Taxol and vinblastine. In addition, the tumor cells enriched with Nanog expression showed reduced apoptosis in response to Taxol treatment. Interestingly, Nanog-enriched prostate carcinoma cells displayed aberrantly activated â-catenin signaling, which is potentially associated with their increased chemo-resistant ability as well as the increased acquisition of epithelial to mesenchymal transition. In summary, Nanog is expressed in prostate cancer cells, especially in those positive for stem/progenitor markers. Enrichment of Nanog expressing cells led to enrichment of tumor cells with increased tumor initiating ability and increased resistance toward chemotherapy. Knockdown of Nanog reduces tumor initiating ability of prostate cancer cells and further sensitizes them toward chemotherapy. The gain-of-function and loss-of-function studies suggest an essential role of Nanog for prostate cancer cells to initiate tumor formation and resist chemotherapy.

Made available in DSpace on 2014-06-11T19:32:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-01Bitstream added on 2014-06-13T19:02:40Z : No. of bitstreams: 1 paiva_ghrg_dr_botib.pdf: 1701322 bytes, checksum: d1fa5b5c562a2a6ce8ad0d14ab948d4a (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O câncer de próstata (CaP) é a neoplasia mais comumente diagnosticada entre homens no ocidente. Embora tratamentos efetivos para a doença localizada estejam disponíveis atualmente, não há terapia curativa para tumores metastáticos. Além disso, os marcadores diagnósticos utilizados na clínica não conseguem discriminar totalmente a evolução diferencial da doença. Desta forma, o conhecimento das diferenças biológicas entre tumores primários confinados ao órgão e metástases é essencial para o desenvolvimento de novos marcadores e identificação de alvos terapêuticos. Neste estudo a análise baseada na metodologia de HR-CGH cromossômico foi realizada para identificar alterações de ganhos e perdas genômicas em três grupos de amostras: o grupo I, que compreende amostras pareadas de tumor primário e respectivas metástases (11 casos); o grupo II, constituído de pacientes que apresentaram seguimento clínico favorável por mais de 10 anos (5 casos); e o grupo III, constituído por diferentes biópsias do mesmo paciente (5 pacientes com 2 biópsias cada). As amostras foram microdissecadas (amostras a fresco: a partir de lâminas de referência; em blocos de parafina: a laser) e após a obtenção de DNA foram amplificadas (amostras de arquivo: PCR-SCOMP) ou marcadas por nick-translation para a realização de HR-CGH. Os resultados de HR-CGH foram comparados com os dados obtidos da análise de CGH-array num subgrupo de amostras e revelaram concordâncias significativas. Os resultados obtidos na presente investigação revelaram perdas dos cromossomos 1p, 2, 3q, 4p, 5q, 7, 8, 9q, 10q, 11q, 12q, 14q, 15q, 16q, 17q, 18q, 19, 20q e 22q em 80% dos casos avaliados. Além disso, perdas em 17q11.2-25, por exemplo, foram detectadas exclusivamente nos tumores do grupo I e nas suas metástases, e não nos tumores do grupo II, sugerindo que esta alteração deve ser importante... / Prostate cancer (PCa) is the most commonly diagnosed non-cutaneous malignancy and the second leading cause of cancer mortality in men from Occident. Although effective treatments for the localized disease are available, there is no efficient therapy for metastatic tumors. Additionally, clinical diagnostic markers are not able to completely discriminate the differential evolution of the disease. The knowledge of biological differences between localized primary tumors and metastasis can establish new molecular markers and therapeutic targets. In this study, an analysis based on HR-CGH methodology was performed to identify imbalances genomic in three groups of samples: group I, paired samples of primary tumors and its metastasis (11 cases); group II, patients that exhibited favorable follow-up over 10 years (5 cases); and group III, different biopsies from the same patient (5 patients with 2 biopsies each). The tumor samples were submitted to microdissection procedures (fresh samples: from reference slides; paraffin embedded samples: laser), DNA extracted and amplified (archive sample: PCR-SCOMP) or labeled by nick-translation to HR-CGH. The HRCGH results were compared with data obtained from CGH-array analysis of a subgroup of samples and revealed significant concordances. In the present investigation, there were observed losses on chromosomes 1p, 2, 3q, 4p, 5q, 7, 8, 9q, 10q, 11q, 12q, 14q, 15q, 16q, 17q, 18q, 19, 20q and 22q in 80% of the cases. Losses in 17q11.2-25, for instance, were detected exclusively in tumor from group I and its metastasis, but were not found in tumors from group II, suggesting that this alteration must be important in the progression of the disease. Five genes were selected after the comparison between the HR-CGH and CGH-array data. The tumor suppressor genes ARID1A, MTSS1, NME1 and S100A4 and TOP2A (oncogenes) were evaluated by quantitative real time... (Complete abstract click electronic access below)

Evidence from international comparisons and migrant studies suggest that environmental factors, such as a Western diet, may be important in prostate cancer development, possibly through effects on hormone and growth factor secretion and metabolism. However, despite considerable research, convincing associations between diet and risk for prostate cancer have not been established. Random and systematic measurement error in dietary assessment using traditional survey methods may contribute to inconsistent findings, particularly as they may not capture adequately specific nutritional constituents of the diet that may be associated with risk, such as fatty acids or vitamins. Validated biomarkers of nutritional factors and hormonal activity, as used in this thesis, provide more precise, objective and integrated measures of exposure, with the capacity to clarify potential mechanisms in the causal pathway of prostate cancer development. Nutritional and hormonal biomarkers investigated for their potential role in the development of prostate cancer include: folate and vitamin B₁₂, which are essential for DNA methylation, repair and synthesis; phytanic acid, obtained predominantly from ruminant fat intake and associated with an enzyme (α-Methylacyl-Coenzyme A Racemase (AMACR)) that is consistently over-expressed in prostate cancer tissue; and insulin-like growth factor (IGF-I), a growth factor influenced by diet and involved in the regulation of cell proliferation, differentiation, and apoptosis. All work presented in this thesis is from the European Prospective Investigation into Cancer and Nutrition (EPIC) study of 500,000 European men and women, using prospectively collected diet and lifestyle data and biological samples. The large number of prostate cancer cases diagnosed during long-term follow-up of EPIC participants enabled investigation of heterogeneity in risk for prostate cancer by time from recruitment to diagnosis (of particular importance for a disease with a long pre-clinical phase) and cancer characteristics such as disease grade and stage. Plasma phytanic acid concentration was highly correlated with dietary intake of fat from dairy products (r = 0.46) and beef (r = 0.30); capturing differences between countries in consumption of fat from these foods. Although phytanic acid is a useful biomarker of ruminant fat consumption, there was little evidence to support the hypothesis that the association between dairy products and prostate cancer risk (as suggested by previous work in EPIC and other studies) is mediated by phytanic acid (OR for doubling in concentration 1.05; 95%CI 0.91 – 1.21; P _trend = 0.53). There was strong evidence for an association between higher circulating IGF-I concentration and risk for prostate cancer (OR for highest versus lowest fourth 1.69; 95% CI: 1.35, 2.13; P _trend = 0.0002). Furthermore, the positive association observed among men diagnosed with advanced stage disease and among men diagnosed more than seven years after blood collection, supports the hypothesis that high IGF-I concentration is associated with clinically significant prostate cancer many years before diagnosis. There was no evidence of an association between prostate cancer risk and dietary folate or vitamin B₁₂ intake, or between circulating levels of folate (OR for doubling in concentration 1.05; 95%CI 0.95 – 1.15; <en>P _trend = 0.33) or vitamin B₁₂ (1.05; 95%CI 0.92 – 1.21; P _trend = 0.47) and only limited evidence for an increased risk associated with elevated vitamin B₁₂ in a meta-analysis of six prospective studies, that included the present study. All of these analyses were based on a blood sample taken at one point in time, with the assumption that this reflects the ‘true’ underlying concentration over the long-term. The poor to modest reliability estimates (intra-class correlation coefficients ranging from 0.18 to 0.48) for circulating concentrations of folate, IGF-I, phytanic acid and vitamin B₁₂ taken in samples approximately six years apart in a sub-sample of participants from EPIC Oxford, show that estimates of usual concentrations based on a single blood measurement weaken the ability to detect associations with disease risk. Where small effect sizes are anticipated, this may bias associations toward the null. In conclusion, there is convincing evidence that IGF-I is an important and potentially modifiable risk factor for prostate cancer many years before diagnosis. However, there is little evidence for an association between biomarkers of folate, vitamin B₁₂ and phytanic acid concentrations and risk for prostate cancer. Future studies should, where possible, incorporate multiple blood samples taken several years apart to better characterise long term relationships between biomarkers of nutritional and hormonal exposure and disease risk and pool individual participant data from multiple prospective studies to strengthen the power to detect modest associations.