No description available.

No description available.

No description available.

Cancer cell attachment to and invasion of an extracellular matrix has been associated with metastatic potential. Recently it has become apparent that the extracellular matrix may influence several phenotype properties of metastatic cancer cells. The mechanisms which regulate prostate cancer growth and metastasis may be particularly relevant to the development of clinical strategies for better understanding and ultimate treatment and control of the disease. Cell-matrix interactions of prostate tumor cells were investigated by comparing the invasive ability through and attachment to reconstructed extracellular matrix components. A correlation was found between metastatic potential and adhesive ability. Non-metastatic AT-1 cells possessed a higher adhesive potential to extracellular matrix components than the highly metastatic cells (Mat-Lu, Mat-LyLu and AT-3) which had higher invasive potentials.

Ngcezu, Sonwarile Arthur. Student no 0200932R. MSc Thesis. Physics. Faculty of Science. 2006. Supervisor: Prof D van der Merwe. / Purpose: A retrospective study was conducted to calculate biological objective functions [Tumor control probability (TCP) for the prostate and normal tissue complication probability (NTCP), in particular for the rectum] for patients treated at Johannesburg hospital during the years 2002 – 2003 for prostate cancer and to correlate these values with observed clinical outcome. Ultimately these results were used to evaluate the effects of dose escalation on tumor control and rectal complications following radiotherapy using conformal external beam radiotherapy. Methods and materials: To calculate the TCP and the NTCP use was made of BIOPLAN, a PC-based software. This software allows the user to evaluate a treatment plan from the point of view of the biological response of the irradiated tissue, providing at the same time flexibility in the use of models (Poisson Statistics for TCP and Lyman-Kutcher-Burman for NTCP) and parameters. The clinical analysis was based on reports from on treatment review and follow-up visits made by the patients periodically after the treatment. PSA was used as a measure of biochemical failure and correlated with calculated TCP. Also, reported complications were compared to NTCP values calculated by BIOPLAN. The follow-up data were about 2 months to 2.5 years old. Results: Complications reported after therapy were all less than grade 3 (RTOG) for the patients, which means only mild complications were reported. No patient reported having necrosis, perforation or a fistula for all the prognostic groups. The calculated average NTCP (mild complications) was 36.3 ± 33.3 % and it was 3.9 ± 3.6 % for severe complications. The calculated TCP had an average of 84.3 ± 7.4 % and no biochemical failure was detected on the follow-ups. As the total dose was elevated through 70-Gy, 72-Gy, 76-Gy, and 86-Gy (2 Gy equivalent), the average TCP increased through 76.2 ± 3.8 %, 77.7 ± 2.6 %, 81.5 ± 4 % and 92.5 ± 2.5 %, respectively. The TCP therefore increased about 22 % by increasing prescribed doses from 70 Gy to 86 Gy. The relation between rectal overlap volume and the NTCP was not obvious (scattered). Conclusions The model predictions gave a reasonable reflection of the reported clinical outcome. A more comprehensive study requires derivation and use of accurate model parameters, and more mature follow-up data.

ABSTRACT Objective The use of conformal radiation therapy in the treatment of carcinoma of the prostate has allowed for dose escalation and improved local control. The dose to the rectum is an important consideration in determining complication rates. This study aims to evaluate the effect of a Foleys rectal catheter balloon on the dose volume histograms to the rectum and to assess the effect of the balloon catheter on prostate gland immobilization during treatment of intermediate risk cancer of the prostate. Design and methods Ten patients with intermediate risk prostate cancer, each acting as his own control, were recruited in the study; eight patients had complete data for analysis. CT scans were done at intervals during treatment, with and without a rectal balloon filled with 30 ml of contrast. 3 pairs of CT scans for each patient were performed and were available for analysis. All patients were treated with 6-field conformal radiotherapy up to 66 Gy followed by a boost of 12 Gy in 3 fractions to the prostate using a rectal balloon and a 3- field plan. Dose volume histograms were calculated for the boost plan with and without the rectal balloon. Movements of the prostate in the superior-inferior and the anteriorposterior directions were measured with and without the balloon for each treatment. There was a slight reduction in the dose received by 1% and 2 % of the rectal volume with the balloon (55% and 52% respectively), compared to without a balloon (57% and 54.3% respectively) (p> 0.05). Results There was a non significant increase in the dose received by 50% of the rectum (p>0.05) with the use of the rectal balloon due to the rectum being pushed towards the symphysis pubis by the balloon. With the use of rectal balloon, the superior / inferior displacement of the prostate was reduced (p=0.04) and a displacement of more than 5 mm was observed in one out of eight patients. The anterior / posterior displacement of the prostate was decreased with the rectal balloon with a mean of 4 mm compared to 5 mm with no rectal balloon. This was not statistically significantly (p>0.05). However, displacement of more than 5 mm was observed in 2 patients with the rectal balloon. No grade 3 acute rectal toxicity was recorded in the 8 patients. Conclusion There was no significant change in the percentage dose received by the rectum with the use of the rectal balloon in this study. The study showed however that the rectal balloon significantly reduced prostate movement during treatment.

Prostate cancer is the most common male-specific form of cancer in the U.K. Current treatments for the aggressive disease by androgen-deprivation therapy gives a rapid initial response, but the disease ultimately progresses into an androgen-independent state for which there are no effective treatments. α-Methylacyl-CoA racemase (AMACR, P504S) is an enzyme which is involved in metabolism of branched-chain fatty acids and the pharmacological activation of some NSAID drugs, such as Ibuprofen and most other ‘profens’. AMACR is over-expressed in prostate cancer and some other cancers, including colon and breast cancers. Reduction of AMACR protein levels inhibits proliferation of prostate cancer cells and restores the requirement for androgens for growth. Although the exact role of AMACR in prostate cancer progression is currently unknown, several other experiments show that AMACR is functionally important for prostate cancer proliferation, validating it as a drug target. There is no convenient high-throughput assay for AMACR and as a result only a few inhibitors have been reported to date. This thesis reports a study on whether other reactions can be catalysed by AMACR. 2-Methyl-3-enoyl-CoA esters are good substrates of AMACR but do not undergo double bond migration, while 2-methyl-2-enoyl-CoA esters are not converted to products. Acyl-CoA esters that contain a fluorine atom at carbon-3 undergo a fluoride elimination reaction to give 2-methyl-2-enoyl-CoA esters. This elimination reaction was investigated for use in the development of a high-throughput assay. A fluorescent binding assay, which can be adapted for the screening of large libraries of compounds, was developed and several known and novel inhibitors were tested. Finally, metabolism of mandelic acid was investigated. It was shown that chiral inversion of mandelic acid in humans proceeds via a different pathway to Ibuprofen and related drugs, in contrast with previous reports.

Prostate cancer (PCa) is a unique and controversial disease. This is at least due to the high prevalence of latent disease, increasing amounts of which is being diagnosed, most of which is indolent and not lead to death, and for which treatment carries significant risks. An increasing concern in medical sociology is how various social structures and actors contribute to the diagnosis and experience of conditions. For PCa, these include print media as an information source for men with prostate cancer (MWPCa), and PCa organisations (PCaOrgs) which have recently emerged in the UK. Yet, there is a distinct lack of UK studies of print media representation of PCa, of PCaOrgs, interaction between the two, and how any of this may impact on the experience of MWPCa. This thesis aims to address this deficit by drawing on narrative and framing theory to study 201 illness narratives of PCa across time: 140 illness narratives of MWPCa in UK newspapers 1990-2010; 20 with MWPCa interviewed in each of 2000 and 2010; and 21 with advocates around PCaOrgs in 2010. I ask: how have PCaOrgs and the UK print media been a force for change in the UK regarding how PCa is addressed and experienced by MWPCa? And more broadly what does this say about narrative structure and form. My findings indicate that though PCaOrgs and print media told stories of injustice around PCa, the substantive focus of this injustice changed over time—from PCa as “neglected” and “taboo” in the 1990s to other “pockets of injustice” since 2000. While one might expect that this to lessen any interactional difficulty that MWPCa experience in disclosing their illness, my study suggests this may not be so. My findings show how ideas of resonance and dissonance contribute to understanding the recursive and repetitive language around PCa.

Prostate cancer (PCa) is the most commonly diagnosed cancer amongst Western males. PCa progression is strongly linked to steroid receptor signalling, however the modulation of steroid receptor expression in PCa is incompletely understood. Lipocalin 2 (LCN2) is a secreted protein which binds to Fe3+-containing siderophores and was originally identified as part of the innate immune response. LCN2 has been proposed as a potential biomarker for a range of cancers. However, LCN2 effects appear to be tissue specific. LCN2 expression is associated with poor prognosis in breast cancer, but with good prognosis in pancreatic cancer where it has been used therapeutically. The role of LCN2 in prostate cancer is poorly understood, in particular its effects on steroid receptor regulation. To elucidate the role of LCN2 in prostate cancer, the LCN2 gene was ectopically expressed in LNCaP cells to generate the LNCaP-LCN2 cell line. LNCaP-LCN2 cells had elevated androgen receptor expression which was linked to increased levels of KLK3 (PSA). LNCaP-LCN2 cells also had reduced levels of Estrogen receptor α (ERα), but increased expression of ERβ. This was combined with higher levels of E-cadherin, but not to changes in other EMT markers. Reciprocally, LCN2 was suppressed using RNAi in the PC3 cell line to generate PC3-shLCN2 cells. PC3-shLCN2 displayed a distinct change in morphology, with increased cell size and a sub-population of multi-nucleated and highly enlarged cells. PC3-shLCN2 cells had reduced proliferation, and lost the ability to form colonies in a 3D substrate. With regards to steroid receptors, PC3-shLCN2 cells had increased ERα expression, but reduced ERβ expression. This was also combined with a loss of E-cadherin and EGFR. Microarray analysis of PC3-shLCN2 cells identified changes to expression of a wide range of genes including VEGF-R, SPARC and KLK6. Functional grouping of differentially expressed genes suggests that LCN2 in involved in a range of cellular processes including hormone receptor response, Wnt signalling and cell cytoskeletal integrity. Many, but not all genes identified by microarray were responsive to recombinant LCN2 protein indicating a paracrine function for the protein. Treatment of PC3 cells with the iron chelator Deferoxamine resulted in phenotypic changes similar to those found in PC3-shLCN2 cells which suggest that LCN2 functions in part due to intracellular iron regulation. In summary, the data presented in this thesis suggests that LCN2 has both pro- and anti- tumourigenic properties in prostate cancer and that the protein is involved in a much wider range of functions than previously described.

Ubiquitination is an extremely important post-translational modification, regulating a wide variety of cellular processes including proteasomal degradation, subcellular targeting, endocytosis and DNA repair. The HECT class of E3 ligases catalyse the final step of ubiquitin conjugation to the substrate; the Nedd4 family make up 9 members of this class in humans, and are implicated in pathologies ranging from congenital ion channel misregulation to cancer, via the TGF-ß signalling pathway. The Nedd4-like proteins contain WW substrate recognition domains, which recognise and bind proline–rich PY motifs. This work focuses on the interaction between Nedd4 and PMEPA1, a membrane protein showing altered expression in prostate cancer and a known Nedd4 substrate. PMEPA1 is recognised as important in several cancers, although its detailed function is not yet known; it is upregulated in prostate cancer and has been postulated to decrease cellular androgen receptor (AR) via a negative feedback loop involving Nedd4 in a ubiquitin-proteasome dependent process. Misregulation of the AR response to testosterone is associated with a more advanced form of prostatic cancer and poor patient prognosis, for which there are currently few treatment options available. PMEPA1 contains two well-documented canonical (PPxY) PY motifs both required for interaction with Nedd4. This work details the identification and characterisation of a third motif with a variant PY (vPY) sequence, QPTY. Our findings indicate that the loss of this vPY motif leads to a significant reduction in Nedd4-dependent ubiquitination in vitro. In addition, the nature of the amino acid residues surrounding the vPY motif also appears to play a role in the functionality of the site. Alongside these experiments, immunodetection of protein levels in HeLa and LNCaP cell lysates was used in conjunction with confocal microscopy to shed light on the interactions between PMEPA1, Nedd4 and AR in vitro and in vivo. A possible non-proteasomal role for ubiquitination in the PMEPA1-AR interaction, as opposed to the simple ubiquitin-proteasome mediated degradation previously proposed, is discussed in the light of this new data. This work has expanded previous knowledge of the specificity of the PY-WW interaction, as well as providing a basis for further investigation, and possibly clinical targeting, of the role of PMEPA1 and AR in prostate cancer.