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The goal of this research is to improve the breast cancer screening process based on magnetic resonance imaging (MRI). In a typical MRI breast examination, a radiologist is responsible for visually examining the MR images acquired during the examination and identifying suspect tissues for biopsy. It is known that if multiple radiologists independently analyze the same examinations and we biopsy any lesion that any of our radiologists flagged as suspicious then the overall screening process becomes more sensitive but less specific. Unfortunately cost factors prohibit the use of multiple radiologists for the screening of every breast MR examination. It is thought that instead of having a second expert human radiologist to examine each set of images, that the act of second reading of the examination can be performed by a computer-aided detection and diagnosis system. The research presented in this thesis is focused on the development of a computer-aided detection and diagnosis system for breast cancer screening from dynamic contrast-enhanced magnetic resonance imaging examinations. This thesis presents new computational techniques in supervised learning, unsupervised learning and classifier visualization. The techniques have been applied to breast MR lesion data and have been shown to outperform existing methods yielding a computer aided detection and diagnosis system with a sensitivity of 89% and a specificity of 70%.

This work presents the first evidence of a ligand-independent role for the glucocorticoid receptor (GR) as a positive regulator of gene expression in mammary cells. We have demonstrated that unliganded GR interacts directly with the promoter of the tumour suppressor gene BRCA1, and upregulates its expression. The presence of the stress hormone hydrocortisone (HC) abolished this interaction and resulted in repression of BRCA1. Since low levels of BRCA1 have been implicated in the development of sporadic breast cancer, this may represent a novel mechanism through which prolonged stress signaling increases breast cancer risk. We determined that the interaction between unliganded GR and BRCA1 is mediated through the beta subunit of the Ets transcription factor GABP at the RIBS promoter element. GR and GABPβ were shown to interact in both co-immunoprecipitation and mammalian two-hybrid assays, and this interaction involved the N-terminal to central regions of both proteins. To further characterize the role of unliganded GR in breast cells, we used shRNA to generate mouse mammary cell lines with depleted endogenous GR expression. Loss of GR resulted in an impaired capacity of cells to differentiate into acini, but this effect was rescued by the addition of glucocorticoids, implicating both the liganded and unliganded forms of GR as key regulators of differentiation. We performed expression microarray to identify targets of unliganded GR using the GR-depleted cell lines. This analysis revealed 260 genes negatively regulated and 343 genes positively regulated by unliganded GR. Many of the positively regulated genes were involved in pro-apoptotic networks, and appeared to oppose the activity of liganded GR targets. Validation and further analysis of five candidates of positive regulation by unliganded GR indicated that two of these, Hsd11b1 and Ch25h, were regulated by unliganded GR in a manner similar to Brca1. The Hsd11b1 enzyme regulates intracellular glucocorticoid levels by interconverting cortisol and its inactive metabolite, cortisone. Further investigation of Hsd11b1 expression and regulation indicated that Hsd11b1 activity appears to be unidirectional in breast cells, specifically inactivating cortisol. Overall, this work suggests that gene regulation by unliganded GR represents a mechanism for protecting the breast from tumourigenesis during stress. / Thesis (Ph.D, Biochemistry) -- Queen's University, 2012-11-29 11:18:14.596

No description available.

Breast cancer is the most prevalent form of cancer in women and accounts for 519,000 annual deaths (WHO Statistics). It has long been established that oestrogen (E2) stimulates tumour growth of oestrogen receptor (ER) positive breast cancer and is involved in the pathogenesis of the disease. Consequently, therapeutic approaches targeting the ER were developed. The use of endocrine therapy is an integral component in treating breast cancer however resistance to such drugs is a major limitation. Unfortunately, even initially responding tumours eventually develop resistance - acquired resistance. The aim of this study was to determine which intracellular pathways may be important in conferring acquired endocrine resistance. In order to do so, a three-stage MCF-7 cell model emulating the clinical development of acquired endocrine was used. MCF-7/LCC1 (LCC1) and MCF-7/LCC9 (LCC9) cells lines were derived from the oestrogen dependent and antioestrogen sensitive MCF-7 cell line. LCC1 cells remain responsive to endocrine therapies but their growth is not dependent on oestrogenic stimulus. LCC9 cells, on the other hand are fully resistant to endocrine therapies and completely oestrogen independent. A number of different cell membrane receptors and intracellular pathways have been implicated in endocrine resistance including HER receptor family, PI3K/Akt & MEK/ERK pathways. These pathways are of particular interest since they are able to activate ER in the absence of oestrogenic stimulus. It is likely that several pathways may be important in conferring resistance to endocrine therapies therefore the experiments in this study focussed on the transcriptional regulation of HER receptors, the activation of the Akt pathway and its implication to basic cellular processes. Following E2 treatment (48h), HER2/3/4 mRNA and protein levels were reduced in MCF- 7 and LCC1 but not in the endocrine-resistant LCC9 cell line as measured by QRT-PCR and Western blotting. The anti-estrogen fulvestrant (ICI 182,780) reversed the E2 modulation. A previous study has shown that ER and the HER2 promoter compete for limiting amounts of SRC-1 in oestrogen-responsive ZR-75-1 cells, causing HER2 repression after E2 stimulation (Newman et al.,Oncogene, 19, 490-7, 2000). ER RNAi abolished E2 repression of HER2 in MCF-7 and LCC1 cells. Furthermore, LCC9 cells have reduced SRC-1 recruitment to ER (assessed by ChIP) allowing SRC-1 to bind to the HER2 promoter. SRC-1 RNAi reduced HER2 transcription in MCF7 cells in a manner similar to E2 whilst it did not restore E2 repression in LCC9 suggesting that the latter cells have alternative mechanisms regulating HER2 transcription. RNAis against the other two p160 co-activators TIF2 and AIB1 did not restore E2 mediated HER2 repression in LCC9 cells. The importance of redundancy between p160 co-activators was also determined by performing double knockouts. SRC-1/TIF2 and TIF2/AIB1 double siRNAs had little effect on HER2 mRNA levels however SRC-1/AIB1 siRNA restored oestrogen mediated downregulation of HER2 transcription in LCC9 cells. This data indicates that SRC-1 and AIB1 co-activators play a role in the transcriptional regulation of HER receptor particularly in MCF-7 and LCC1 cells. The regulation of this transcriptional mechanism is altered in resistant LCC9 cells but, as evidenced by the double knockouts, p160 coactivators are still able to affect HER expression in these cells. This mechanism was further studied in primary breast cancer tumour material. The importance of the Akt pathway in this cell line model was also investigated as phospho-Akt levels are elevated in LCC1 and LCC9 cells. This in turn was shown to activate mTOR and ER (Ser167 residue phosphorylation) thereby contributing to increased growth and ligand independent activation of the oestrogen receptor respectively. Activation of PI3K and PTEN is unchanged in LCC1 and LCC9 cells suggesting that these proteins are not responsible for elevated Akt phosphorylation. In contrast, these cells do express higher levels of phospho-IGFR due to the high availability of receptor ligands (IGFI & IGFII). This is likely to be, at least partially, responsible for the elevated Akt activation. Moreover, the role of Akt isoforms was also determined as they are known to have different functions. The levels of Akt 2 phosphorylation are higher in endocrine resistant cell lines in comparison to parental MCF-7 cells. Interestingly, the Akt 3 phosphorylation is present in all cell lines whilst Akt 1 phosphorylation is minimal. Nevertheless, Akt RNAi studies reveal that Akt 1 and 2 siRNA dramatically reduce growth in MCF-7, LCC1 and LCC9 cells. These results suggest that Akt 2 phosphorylation may play a part in conferring endocrine resistance but the other isoforms are also important for normal cellular growth. The cell cycle profiles of LCC1 and LCC9 are very similar to MCF-7. Similarly, migration levels are unchanged in endocrine resistant cell lines. However, in the presence of antioestrogenic drugs, apoptosis in LCC1 and LCC9 cells in reduced in comparison to the parental MCF-7 cell line. Furthermore, LCC1 and LCC9 cells have higher invasion rates. The deregulation of HER receptor expression and elevated Akt activation may together confer survival advantage in LCC1 and LCC9 cells whilst also increasing their invading potential.

This work is focussed on the analysis of breast tumour physiology by pharmacokinetic modelling of dynamic contrast enhanced MRI (DCE-MRI) data. DCEMRI consists of the intravenous bolus injection of a small molecular weight contrast agent into the patient followed by the rapid acquisition of MR images across both breasts. Due to the leaky nature of the lesion microvasculature there is a greater uptake of contrast agent within the tumour than in the surrounding tissues. The dynamic contrast enhanced MR signal curve can be fitted by compartmental analysis providing information linked to the tumour’s permeability and flow. The effect of the DCE-MRI acquisition parameters on the accuracy of the estimated pharmacokinetic quantities was investigated together with the assumptions lying behind the pharmacokinetic model used for the fitting. Contrast enhanced MRI data were also examined using a fractal measure of tumour heterogeneity with the aim of assessing whether this could be a potential predictor of the tumour response to chemotherapy. Among the factors believed to play an important role in terms of tumour treatment is an increased interstitial fluid pressure (IFP) in the central areas of some large tumours. Here DCE-MRI data were analyzed in a way to see whether it could provide any information related to IFP distribution across tumour volumes. Finally, when performing quantitative DCE-MRI, particular care needs to be taken in the choice of an arterial input function (AIF) which accurately describes the passage of the contrast agent bolus at the lesion location. Here a new approach was proposed and demonstrated for the estimation of a tumour capillary input function together with lesion pharmacokinetic parameters. This was achieved by optimizing the capillary input function with a measure of the patient’s cardiac output, a parameter which is expected to vary depending on the patient’s pathology/physiology.

Bakgrund: Bröstcancer är den vanligaste cancerformen hos kvinnor och antalet bröstcancerfall ökar. En cancerdiagnos leder till många emotionella förändringar. Som vårdpersonal är det viktigt att ha vetskap och förståelse om patientens subjektiva upplevelser kring sin sjukdom för att kunna ge en god vård. Syfte: Syftet med litteraturstudien är att beskriva kvinnors upplevelser av att leva med bröstcancer. Metod: Databaserna PubMed och Cinahl användes i sökningen av artiklar. Resultaten i artiklarna har analyserats genom en analysmetod för kvalitativa studier och resultatet i litteraturstudien baseras på 14 vetenskapliga artiklar av kvalitativ ansats. Resultat: Kvinnorna upplevde negativa förändringar i deras vardagliga liv relaterat till sjukdomen både fysiskt, psykiskt och socialt. De upplevde en förändrad roll i familjen och som kvinna. Vilken och hur mycket information kvinnorna önskade få om sitt tillstånd varierade. Kvinnorna fick en ny syn på livet och de uppskattade livet mer än de gjorde innan sjukdomen. Slutsats: Kvinnorna upplevde många svårigheter i och med bröstcancersjukdomen och dessa upplevelser är viktiga att ha i beaktande i vårdandet av patienter med bröstcancer. / Background: Breast cancer is the most common cancer amongst women and the amount is increasing. Diagnosed by cancer leads to many emotional changes. To be a nurse it’s very important to be knowledge about the disease and to understand the patient’s experience during the cancer period in order to give good treatment. Objective: The purpose of this literature study is to describe women’s experiences on how to live with breast cancer. Method: The databases PubMed and Cinahl are used in the search of articles. The results have been analyzed through an analyzed method for qualitative studies and the result of the literature is based on 14 science articles of qualitative approach. Results: The women experienced negative changes in their everyday life related to the disease when it comes to physical, mental and social experiences. They experienced a change in their role both as a mother and as a women. Which and how much information the women wished to retain regarding their status varied. The women got a new outlook on life and they appreciated life more than they did before the disease. Conclusion: The women experienced many difficulties because of the breast cancer and these experiences are important to keep in mind when treating breast cancer diagnosed patient.

In the only human study to date arginine supplementation stimulated tumour protein synthesis in patients with breast cancer. However, it is not known if these stimulatory effects of arginine are limited to breast cancer, and the mechanisms of its action are not well understood. Moreover it would be important to find out whether the action of arginine is selective for malignant tissues or if it can affect normal, healthy tissues. The first study investigated the effect of arginine supplements for 3 days on nitrogen balance and on the liver synthesis rate of albumin in healthy volunteers. The addition of arginine to the diet produced a remarkable nitrogen retention over the three days. No changes in the albumin synthesis rates were detected between the two dietary periods. No effects were observed on the protein synthesis, RNA content or transcriptional efficiency in a variety of the tissues when adult rats were supplemented with arginine for three days. In vitro studies using a human breast tumour cell line (MCF-7) showed that arginine is an essential nutrient for the proliferation of breast tumour cells. Neither the direct precursor for polyamine synthesis, ornithine, nor the polyamine putrescine could replace arginine for growth. Only citrulline could completely substitute arginine for protein synthesis and growth. The arginine:nitric oxide pathways did not seem involved in the stimulatory effects of arginine. The main reason for the high arginine requirement was found to be the production of the enzyme arginase. The final study investigated the in vivo effects of arginine supplements on human tumours. Arginine supplementation did not affect the tumour protein synthesis rates in patients with head and neck tumours, suggesting that not all human tumours are stimulated by arginine.