Background LHRH agonists decrease tumour size/activity by suppressing testosterone in prostate cancer; however, initial injection causes testosterone surge that triggers flare symptoms. Anti-androgen given with agonist may reduce/avoid flare symptoms. When LHRH antagonist/blocker is introduced, testosterone suppression is immediate, but there is uncertainty about significance of flare symptoms without anti-androgen. Objective Systematic review compared significance of flare symptoms avoided and cost utility analysis using modelling comparing incremental value of blocker (degarelix) OR agonist (goserelin)+anti-androgen (bicalutamide) VERSUS agonist alone in prostate cancer patients. Outcome Incremental cost/QALY of bone pain as flare symptom between treatments Results Thirteen studies were reviewed. There was no standard definition for flare symptoms or data on LHRH antagonist versus other treatments on flare. From societal perspective, goserelin+bicalutamide was dominated over goserelin alone and similarly, from public perspective, goserelin+bicalutamide had favourable cost effectiveness profile against goserelin. Conclusion With bone pain as clinical endpoint, LHRH agonist+anti-androgen had favourable cost-effectiveness profile compared to goserelin.

Background: The prostate specific antigen (PSA) test has been available for physicians and free of charge to residents in Saskatchewan since 1990. The PSA test witnessed great growth in use indicative of screening but it was unknown who was being tested, how often, which physicians were ordering PSA tests, or what the variation in utilization was in the population. Whether widespread use of the PSA test resulted in a stage shift among newly diagnosed prostate cancers or changed the clinical management of the disease was also unknown. The purpose of this research was to describe in detail how the PSA test is being used in the Saskatchewan population and investigate the impact of testing on the diagnosis and clinical management of prostate cancer during the PSA era.<p> Methods: Individual records were retrieved from the two labs in Saskatchewan capable of analyzing PSA serum samples. The PSA data represented almost all PSA tests in the population for the five-year period 1997-2001. The PSA data included date of the PSA test, a unique identifier of the men tested, test results including total PSA and the free-PSA amount (for November 1999 to December 2001), and an ID of the physician who ordered the test. This data was linked to the population-based Saskatchewan Cancer Registry to determine who had a previous or subsequent prostate cancer diagnosis and to secure tumour characteristics and clinical management data. This combined data was then linked to Saskatchewan Health data files to obtain information about biopsy procedures and to determine the geographic residence of men at the time of their PSA tests. De-identified data was returned for descriptive analysis.<p> Results: Over 60% of men aged 50 and over had at least one PSA test during 1997 to 2001. Even among men 40-49, 27% had at least one PSA test and there were over 5,300 tests done in men under 40 years of age. Sixteen percent of men 40-49 who had PSA tests had more than one and this percentage increased with age to 59.4% for men in their 70s. Over 80% of all PSA tests were ordered by general practitioners and there were significant geographic variations in testing patterns. Knowledge of the free-PSA-ratio, which began in 1999, reduced biopsy rates 4.7% and increased cancer detection 8.7% for men with total PSA test results in the 4.0-10.0ng/ml range, however these rates were also very age specific. The age-adjusted incidence rate of organ confined disease increased from 38.5 per 100,000 to 108.8 per 100,000 from 1985 to 2001. Almost 80% of prostate cancers were detected by needle biopsy in 2001 compared to only 34% in 1985, while 20% of cases in 2001 were treated with radical surgery compared to only 2% for 1985. Mortality rates have remained stable up to 2001.<p> Conclusion: PSA testing is very common in Saskatchewan consistent with extensive screening activity. Conflicting guidelines and the universal availability of the test has resulted in significant inappropriate testing and considerable variation of use. Most prostate cancers are now found by needle biopsy and are organ confined at the time of diagnosis. No benefit in prostate cancer mortality has yet been realized in Saskatchewan from extensive PSA testing.

A beta-emitting glass seed was proposed for the brachytherapy treatment of prostate cancer. Criteria for seed design were derived and several beta-emitting nuclides were examined for suitability. 142Pr was selected as the isotope of choice. Seeds 0.08 cm in diameter and 0.9 cm long were manufactured for testing. The seeds were activated in the Texas A&M University research reactor. The activity produced was as expected when considering the meta-stable state and epi-thermal neutron flux. The MCNP5 Monte Carlo code was used to calculate the quantitative dosimetric parameters suggested in the American Association of Physicists in Medicine (AAPM) TG-43/60. The Monte Carlo calculation results were compared with those from a dose point kernel code. The dose profiles agree well with each other. The gamma dose of 142Pr was evaluated. The gamma dose is 0.3 Gy at 1.0 cm with initial activity of 5.95 mCi and is insignificant to other organs. Measurements were performed to assess the 2-dimensional axial dose distributions using Gafchromic radiochromic film. The radiochromic film was calibrated using an X-ray machine calibrated against a National Institute of Standards and Technology (NIST) traceable ion chamber. A calibration curve was derived using a least squares fit of a second order polynomial. The measured dose distribution agrees well with results from the Monte Carlo simulation. The dose was 130.8 Gy at 6 mm from the seed center with initial activity of 5.95 mCi. AAPM TG-43/60 parameters were determined. The reference dose rate for 2 mm and 6 mm were 0.67 and 0.02 cGy/s/mCi, respectively. The geometry function, radial dose function and anisotropy function were generated.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Pharmaceutical Science." Includes bibliographical references (p. 178-196).

The link between obesity and the risk of prostate cancer (PCa) is inconclusive. However, studies demonstrate a correlation between obesity, advanced PCa and mortality. Investigating the underlying biological mechanisms by which obesity promotes advanced PCa is necessary to develop potential therapeutic targets that may aid in the efficacy of treating obese men. Obesity-associated changes in tumor biology may modulate key aspects of the hallmarks of cancer; acquisition of characteristics essential for the development and progression of cancer. We hypothesized obesity-induced inflammation promotes PCa progression. Our studies incorporated cell culture and murine models to investigate the role of obesity-related systemic factors on AR signaling, inflammation-stimulated invasive PCa, and the paracrine interaction of the tumor-microenvironment (TME). We sought to recapitulate the systemic effects of obesity to investigate characteristics of the metastatic cascade. Briefly, sera from mice fed 60% or 10% kcal from fat diet for 12 weeks were used for in vitro studies. PCa cells exposed to sera from obese mice increased AR transcriptional activity, proliferation, invasion, migration, MMP-9 activity and EMT: e-cadherin, vimentin and β-catenin. PCa cells exposed to sera from 1 hour maintained the invasive phenotypes similar to PCa cells directly exposed to sera from obese mice. IL-6 is associated with advanced PCa cancer. Depleting sera of IL-6 or IL-6 shRNA suppressed obesity-induced proliferation, invasion, migration and MMP-9 activity in LNCaP cells. Furthermore, in a PTEN spontaneous model of PCa, IL-6 protein and mRNA levels corresponded with progression of PCa in mice fed a high-fat diet. These results suggest IL-6 mediates obesity-induced PCa progression. Stromal cells that comprise the TME vary in their contribution to the growth of tumors. Our studies show macrophage-like and myofibroblasts increased NF-kB activity in PCa cells exposed to sera from obese mice. An increase in NF-kB activity corresponded with proliferation, prostaglandin E2, and invasion and recruitment of stromal cells by PCa cells. In summary, obesity-related systemic factors promote an invasive PCa phenotype, which may be mediated by Akt, AR, IL-6 and the TME. Obesity-induced changes in tumor biology and the microenvironment provide a niche suitable for invasive prostate cancer. / text

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

Prostate cancer is the second leading cancer in men. A large amount of polyamines are synthesised in the human prostate and are involved in prostate cell growth and its physiological functions. The content of intracellular polyamines is closely related to cell growth. An increase in cell growth is accompanied by a rise of intracellular polyamine content, and a depletion of intracellular polyamine pools can cause growth arrest or cell death. Therefore, maintaining polyamine concentrations is critical to the cell. Spermidine/spermine N1-acetyltransferase (SSAT) is the first and rate-limiting enzyme in the polyamine catabolic pathway. SSAT gene is highly inducible, with many stimuli including polyamine analogues and some anticancer drugs producing dramatic increases in activity. Many studies have focussed on polyamine analogues as inducers of SSAT activity as increases in SSAT are associated with a growth inhibition in many tumour cells. However, the mechanisms of this inhibition are not fully understood with respect to polyamine content. Additionally, in vivo results in SSAT transgenic mice studies are contradictory. For example, prostate carcinogenesis is reduced in TRAMP mice but Apcmin/+ mice show a promoted intestinal tumorigenesis. It is thus necessary to characterise the regulation of polyamine content and metabolism by SSAT in prostate cancer cells. The aim of the present study was to characterise the role of SSAT in both the growth of LNCaP prostate carcinoma cells and the response of these cells to anticancer drugs. Our hypothesis is that increased SSAT activity will inhibit cell growth and that this is associated with a decrease of intracellular polyamine pools. Furthermore, if SSAT induction is an essential part of the response of cancer cells to anticancer drugs, then altered SSAT activity should affect sensitivity of the cells to the drugs. The present study used a cell culture model of human prostate cancer: LNCaP wild type (WT) and SSAT cDNA transfected prostate carcinoma cell lines. The expression of SSAT in the transfected cell line (SSAT- & SSAT+) was controlled through the “Tet-off” system. This model system provided a background for comparison of effects under basal (WT), low (SSAT-), and high (SSAT+) SSAT activity. Due to our interest in acetylpolyamine derivatives and their low concentrations in cells, a new method for quantifying polyamine concentrations was developed using liquid chromatography-mass spectrometry (LC-MS). This method was highly sensitive and can detect polyamines about 250 fold lower than HPLC, as well as N-acetylpolyamines and N1,N12-diacetylspermine. In addition, a variety of methods were utilised to measure cell growth, enzyme activity, protein expression, polyamine efflux and apoptosis, which includes enzyme assays, western blot, radiochemical labelled assays, flow cytometry, spectrophotometry and fluorescent microscopy. A stable increase in SSAT activity was inhibitory to the cell growth. This inhibition was associated with significant changes in the activity of the polyamine pathway. The alterations included an increase in ODC, APAO, and SMO activity; an accumulation of intracellular N1-acetylspermidine and putrescine; a decrease in intracellular spermidine and spermine; an increased polyamine flux and efflux; and an increase in apoptosis. Combination treatment to the cells with DFMO and MDL72527 partially restored the growth of SSAT+ cells. The original contribution of this study to the field is that the cells with a higher SSAT activity are less sensitive to aspirin and 5-FU, and the sensitivity increased while the overexpressed SSAT activity decreased. The growth inhibition was associated with a depletion of total intracellular polyamine pools by the drug treatments. Moreover, to our knowledge, it is first time that the extracellular polyamine concentrations were quantified by LC-MS in human tumour cells. Overall, an increase in SSAT activity led to an inhibition of prostate cancer cell growth, and vice versa. Thereby, this study suggests that SSAT is a potential target for novel drug discovery for cancer chemotherapy or chemoprevention. For example, a combination treatment could be designed that acts as an inducer of SSAT activity in tumour cells, leading to an inhibition of the cell growth in the first place and increased sensitivity to cytotoxic agents. This would then be followed by an agent to decrease SSAT activity when the sensitivity of cancer cells to the cytotoxic treatment was optimal.

The proliferation and differentiation of normal prostate epithelial cells depend upon the action of the androgens, testosterone and dihydrotestosterone. Prostate cancer cells retain the ability to respond to androgens in the initial stages of cancer development but progressively become independent of exogenous androgens in advanced stages of the disease while maintaining the expression of functional androgen receptor (AR). We hypothesized that prostate cancer cells in the advanced stages of the disease acquire capability to synthesize androgens which activate AR in an intracrine manner. To test this hypothesis, we determined the expression of proteins and enzymes involved in cholesterol uptake, transport and its conversion into testosterone in androgen-dependent and androgen-independent prostate cancer cell lines. Established androgen independent prostate cancer cell lines, PC3 and DU145 cells, expressed mRNA and proteins for scavenger receptor type B 1 (SRB 1), steroidogenic acute regulatory (StAR) protein, metastatic lymph node 64 (MLN64), cytochrome P450 cholesterol side chain cleavage (CYP11), and other enzymes involved in androgen biosynthesis. Expression of all these proteins and enzymes was significantly higher in the androgen-independent derivative of LNCaP prostate cancer cells (C81) than in the androgen-dependent cell line (C33). In serum free cultures, the androgen independent cell line C81 secreted ~5 fold higher testosterone than C33 as determined in the conditioned media by specific immunoassays. These cells also converted radioactive cholesterol into testosterone which was identified by thin layer chromatography. To evaluate the effects of endogenous production of testosterone on the survival and growth of prostate cancer cells, C81 cells were treated with either aminoglutethimide to prevent conversion of cholesterol to pregnenolone or the AR antagonist, bicalutamide. Our results demonstrated growth inhibition ofC8l cells and a reduction in expression of the AR regulated genes, PSA and TMPRSS2 in aminoglutethimide and bicalutaniide treated cells which were reversed by exogenous androgens. These results indicate that prostate cancer cells in advanced stages of the disease synthesize androgens from cholesterol. These androgens activate AR in an intracrine maimer to regulate cell survival and proliferation. The ability of the prostate to synthesize androgens may be associated with progression to castration resistant prostate cancer and possibly represents a therapeutic target for advanced disease.

Cancer metastasis is a multi–step process that initiates with a tumor cell obtaining the ability to migrate. A multitude of changes occur in such a cell including changes to cell adhesion molecules such as integrins. In cancer cells, integrins are known to be involved in migration, invasion and metastasis. Investigation by our group of the α6 integrin led to the discovery of a cleaved form of the integrin lacking the ligand binding domain, called α6p. While it is known that the integrin is cleaved by urokinase plasminogen activator (uPA) little is known about how this process is regulated. There is a need to better understand the players involved in regulation of α6 cleavage as inhibiting this event from occurring may contribute to prolonged or increased patient survival or ultimately a cure.The existence of the integrin–actin complex has been known for many years. In this study actin was identified as a potential regulator of α6 cleavage. Using a diverse set of tumor cell lines (DU145, PC3 and MDA–MB–231) and a number of actin modifing compounds (latrunculin A, jasplakinolide and siRNA) it is reported here that disassembling actin filaments leads to an increase in α6p production. Although the increase in cleavage product did not always correlate with an increase in uPA receptor, an increase in uPAR was observed when actin was complexed by small molecule inhibitors. Taken together the results demonstrate a potential role for actin filaments to protect α6 integrin from uPA–uPAR induced cleavage via a multi–protein complex.