As a master regulator of the epithelial state, p63 is a family member of the well-known tumor suppressor p53. It has previously been connected to a cancer-associated process, epithelial-to-mesenchymal transition (EMT), and here we find that it can be regulated by oncogenes involved in breast tumorigenesis. Specifically, activated forms of PIK3CA and H-RAS are able to strongly repress expression of ∆Np63α, which is the major p63 isoform in epithelial cells. In mammary epithelial lines, this oncogene downregulation occurs at the transcriptional level, and complete repression occurs over the course of several days. As p63 is repressed, the cells undergo EMT and acquire the ability to invade individually through a 3D collagen matrix. Strikingly, even when p63 is suppressed but no oncogene action is present, these cells undergo a mesenchymal shift, suggesting the importance of this gene in maintaining the epithelial state. Furthermore, it is particularly interesting that p63 protein and RNA levels are often low in breast tumors. By connecting H-RAS and PIK3CA signaling to p63, it is hypothesized that such oncogene suppression could account for tumor progression in cases where p63 levels are low. Here, it is proposed that p63 acts in a tumor-suppressive manner, although it can be overcome by oncogenes leading to changes in differentiation state and migratory capability, therefore drastically affecting breast carcinogenesis.

Background: Estrogen receptor (ER)- and progesterone receptor (PR)-negative (ER-PR-) breast cancer is associated with higher grade and poorer prognosis compared with other breast cancer subtypes. High parity, coupled with lack of breastfeeding, has been associated with an increased risk of ER-PR- cancer. The mechanism of this etiology is unclear, and may be obfuscated by ER and PR correlation with each other as well as other prognostic tumor characteristics. Methods: Using population-based and clinic-based ascertained cases and controls from the Breast Cancer Family Registry, I examined reproductive risk factors, including parity, breastfeeding, and oral contraceptive (OC) use, in relation to ER and PR status, using polytomous logistic regression (for the population-based data) and the method of generalized estimating equations (GEE) (for the clinic-based data) as well as the pseudo-conditional likelihood approach, which accounts for correlated outcome variables. Results: High parity (≥ 3 live births) combined with lack of breastfeeding, was positively associated with ER-PR- tumors (odds ratio [OR]=1.57, 95% confidence interval [CI] 1.10-2.24, population-based cases vs. controls) relative to nulliparity. There was no association with ER-PR- tumors and parity in women who breastfed (OR=0.93, 95%CI 0.71-1.22) relative to nulliparous women. Associations with ER-PR- cancer were higher across all races/ethnicities among women who did not breastfeed compared with women who did. Population-based and clinic-based data were generally in agreement (OR=2.07, 95% CI 1.09-3.91, clinic-based cases vs. controls, relative to nulliparity). When adjusted for the correlation of PR-status and grade, to ER-status, the association between high parity +lack of breastfeeding and ER- status, was maintained. OC use before year 1975 was associated with an increased risk of ER-PR- tumors (OR=1.32, 95% CI 1.04-1.67, population-based data, cases vs. controls) relative to never use of OCs. For women who began OC use in 1975 or later there was no increased risk. Analysis of OC use in clinic-based data agreed with the findings of the population-based data. Conclusions: My findings support that there are modifiable factors for ER-PR- breast cancer, and that breastfeeding in particular may mitigate the increased risk of ER-PR-cancers seen from multiparity. The mechanism of both risk and risk mitigation may operate primarily through the estrogen, rather than progesterone, pathway.

Introdução: O câncer de mama é a neoplasia maligna mais prevalente em mulheres. Em decorrência do diagnóstico tardio, a mastectomia radical modificada (MRM) permanece como tratamento cirúrgico de escolha para a maioria das pacientes portadoras da doença. Em pacientes mastectomizadas, a reconstrução mamária com retalhos miocutâneos é a técnica que apresenta melhor resultado a longo prazo. Material e métodos: O estudo compara as taxas de recorrência local e sistêmica e a sobrevida livre de doença em pacientes submetidas à MRM, associada ou não à reconstrução mamária imediata com retalho miocutâneo transverso do reto abdominal (TRAM). Resultados: O grupo submetido à TRAM apresentou recorrência local de 11,8% e sistêmica de 35,7%, e o grupo da MRM, 4,4 e 26,1%, respectivamente. A sobrevida livre de doença (tempo decorrido entre a cirurgia e a primeira recorrência) foi, em média, de 105,4 meses (IC95% 97,0-113,72) no grupo MRM e de 95,4 meses (IC95% 80,7-110,0) no grupo TRAM, não havendo diferença estatisticamente significativa entre os grupos (P = 0,147). Conclusões: Em pacientes portadoras de câncer de mama, a reconstrução mamária imediata com retalho miocutâneo transverso do reto abdominal não influencia o prognóstico da doença, devendo ser oferecida às pacientes que não apresentam contraindicação clínica ao procedimento. / Introduction: Breast cancer is the most prevalent malignant neoplasia among women. In cases of late diagnoses, modified radical mastectomy (MRM) remains the surgical treatment of choice for most women with this disease, and breast reconstruction with myocutaneous flaps is the technique with the best long-term results. Material and methods: Local and systemic recurrence rates were compared, as well as diseasefree survival of patients who underwent MRM with or without immediate breast reconstruction using transverse rectus abdominis myocutaneous flap (TRAM). Results: The TRAM group had a local recurrence rate of 11.8% and a systemic recurrence rate of 35.7%; for the MRM group, these rates were 4.4 and 26.1%, respectively. Disease-free survival time (from surgery to first recurrence) was 95.4 months (95%CI 80.7-110.0) in the TRAM group and 105.4 (95%CI 97.0-113.72) in the MRM group, but the difference was not statistically significant (P = 0.147). In patients with breast cancer, immediate breast reconstruction with TRAM did not affect disease prognosis, and may be indicated to all patients who undergo MRM, except those with any clinical contraindications to the procedure.

Thesis (M.Sc. (Biochemistry)) -- University of Limpopo, 2019 / Survivin is the smallest and a well-studied member of the inhibitors of apoptosis proteins (IAPs) family, which is involved in the regulation of cell division, inhibition of both caspasedependent and -independent apoptosis in cancer cells and promotion of angiogenesis. Survivin is detectable during embryonic and foetal development but is undetectable in normal adult tissues. It is, however, expressed in transformed cell lines as well as in most common types of human cancers. Regulation of survivin remains poorly understood, and the discovery of the regulatory biomolecules, microRNAs (MiRs) present an interesting opportunity to investigate the regulation of this protein and its variants in cancers, especially breast cancer. Additionally, the expression of the survivin splice variants during cell cycle progression and apoptosis is not fully understood. The aims of this study were to investigate the role of arsenic trioxide on the expression of survivin splice variants and their specific microRNAs during cell cycle progression and apoptosis in human breast cancer MCF-7 cells. The study also aimed at ascertaining the toxicity and efficacy of using coal fly ash-derived β-cyclodextrin carbon nanospheres to deliver arsenic trioxide into the MCF-7 cells. Carbon nanospheres (CNSs) were synthesised using a chemical vapour deposition method while arsenic trioxide was deposited using wet impregnation method to form the arsenic trioxide-β-cyclodextrin carbon nanospheres (ATO-β-cyclodextrin-CNSs). The formation of the CNSs and the loading of arsenic trioxide to CNSs were confirmed using scanning electron microscopy/energy dispersive X-ray detection (SEM-EDX). The in vitro cytotoxicity effect of the β-cyclodextrin carbon nanospheres (CNSs), arsenic trioxide and arsenic trioxide-β-cyclodextrin CNSs against KMST-6 and MCF-7 cells was analysed using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide (MTT) Assay, Muse® Count and Viability Assay and light/fluorescence microscopy. Cellular apoptosis, cell cycle analysis, Multi-Caspase activation, mitochondrial membrane potential, MAPK activation and PI3K activation were analysed using the Muse® Cell Analyser. Polymerase Chain Reaction (PCR) and Immunohistochemistry were used to analyse survivin mRNA variants and protein expression, respectively. The survivin specific MiRs were predicted using both bioinformatics platforms and literature surveys. In order to understand the applicability of delivering arsenic trioxide for the treatment of breast cancer, skin fibroblast (KMST-6) and MCF-7 cells were exposed to β-cyclodextrin CNSs. The novel β-cyclodextrin CNSs did not show any cytotoxic effect on the KMST-6 cells but demonstrated such activity against the MCF-7 cells. More so, arsenic trioxide-βcyclodextrin CNSs were found to significantly reduce the viability of the MCF-7 cells and were shown to inhibit their cell growth through the induction of apoptosis. The MTT Assay results revealed arsenic trioxide inhibited the growth of the MCF-7 cells in a concentration-dependent manner. The Muse® Cell Analyser showed that arsenic trioxide induced G2/M cell cycle arrest and promoted cellular apoptosis without any damage to the mitochondrial membrane of MCF-7 cells. Furthermore, arsenic trioxide also deactivated two survival pathways, Mitogen-Activated Protein Kinase (MAPK) and Phosphoinositide 3-Kinase (PI3K) signalling pathways in MCF-7 cells. The deactivation of the two pathways was shown to be accompanied by the upregulation of survivin 3α during arsenic trioxide-induced G2/M cell cycle arrest and apoptosis. Survivin 2B was found to be upregulated only during arsenic trioxide-induced G2/M cell cycle arrest, but downregulated during arsenic trioxide-induced apoptosis. However, wild-type survivin was highly expressed in untreated MCF-7 cells, but the expression was upregulated during arsenic trioxide-induced G2/M cell cycle arrest and was downregulated during arsenic trioxide-induced apoptosis. Survivin variant ΔEx3 was undetected in both untreated and treated MCF-7 cells. Survivin 2α was upregulated during arsenic trioxideinduced apoptosis whereas, survivin 3B was only detected in the untreated MCF-7 cells. Additionally, survivin proteins were localised in both the nuclei and cytoplasm in MCF-7 cells and highly upregulated during arsenic trioxide-induced G2/M cell cycle arrest, which can be attributed to the upregulation of survivin-2B. Using TargetScan, MIRD and mirTarbase, a few MiRs were identified and confirmed to target wild-type survivin, survivin 2B and survivin ΔEx3. These include the MiR-542-3p and MiR-335-5p, which are both upregulated during apoptosis and MiR-218-5p, which is upregulated during cell arrest. MiR-218-5p targets survivin 2B, which was upregulated during G2M cell cycle arrest. The fly ash-derived CNSs can be used to deliver arsenic trioxide for therapeutic purposes, especially against breast cancer. Most importantly, these nanoparticles induced typical apoptotic characteristics in breast cancer MCF-7 cells. Arsenic trioxide can be used as therapeutic target for breast cancer treatment and nanotechnology can be used for its delivery. This study provided the first evidence that novel survivin 2B splice variant may be involved in the regulation of arsenic trioxide-induced G2/M cell cycle arrest only. This splice variant can therefore, be targeted for therapeutic purposes against Luminal A breast cancer cells

Breast cancer is the second leading cause of cancer death among women in the United States. Nonadherence to recommended screening guidelines and lack of screening contribute to late stage diagnosis and increased morbidity and mortality among racial and ethnic women in the United States. The purpose of this study was to assess breast cancer screening practices, knowledge, and beliefs among Cameroonian immigrant women who were 40 years and older living in the metropolitan Washington, D.C. region. This quantitative cross-sectional study was guided by the health belief model and used the revised version of Champion's health belief model scale. A convenience sample (N=267) responded to a 60-item self-administered online survey that assessed knowledge of breast cancer screening, demographic variables, constructs of the health belief model and adherence (defined as obtaining a mammogram within two years). Data analyses performed included descriptive analysis, correlational and multiple linear regression. Results of this study revealed that increased level of education and self-efficacy were associated with greater knowledge of the benefits of mammography. Additionally, women who had more self-efficacy in obtaining a mammogram, perceived less cultural barriers, lived longer in the United States, and who had a regular healthcare provider were more likely to be adherent. Study findings suggest that positive social change can be achieved by empowering women to take control of their health. Efforts promoting awareness of breast cancer screening guidelines and facilitating access to a regular healthcare provider could significantly increase uptake of screening services and lead to better health outcomes and reduced mortality.

The aim of the present study was to determine if a nutrition and yoga intervention will improve quality of life (QoL) in breast cancer survivors (BCS). Using the Transactional Model of Stress and Coping as a guide to lead the intervention, the intervention assessed potential barriers, self-efficacy, diet quality, and physical activity as it relates to quality of life. Twenty-seven women were enrolled in the study and randomly assigned to the control or intervention group. The intervention consisted of 6-weeks of yoga classes and 6-weeks of online nutrition education. The control group received a nutrition consultation and nutrition guidelines from the American Cancer Society. Measurement of variables was conducted at baseline, post-intervention (6 weeks), and follow-up (12 weeks). One-way repeated measures ANOVA, paired samples t-test, and post hoc analysis with Bonferroni adjustment was used to analyze the data. Mediation analysis with regression was performed to demonstrate the effect the intervention had on quality of life. The intervention elicited a statistically significant difference in the Total Outcome Index quality of life score from baseline to post-intervention (P < .005) and from baseline to follow-up (P < .005) in the intervention group. The frequency of how often fruits and vegetables were consumed was significant between time points, (P < .05), but not between the control and intervention group, P = .538. The amount of fruit and vegetables consumed each time was statistically significant for the intervention group from baseline to post-intervention (P < .05) however there was no significant difference from baseline to follow-up (P = .067). There was no difference between the control and intervention group, (P = .216). There was a statistically significant difference for physical activity for time (P P = .166) however the intervention group has a statistically significant difference between baseline and post-intervention (PP = .082). We cannot confidently predict that participant’s quality of life scores are determined by group with the help of mediators after conducting a mediation analysis with regression. A six-week nutrition and yoga intervention in BCS elicited significant changes in QoL in BCS. Even though the results did not show significant changes between the control and intervention group there were significant changes within the intervention group from baseline to post-intervention and baseline to follow-up which may indicate a 6-week online nutrition education program coupled with a 6-week yoga intervention an effective tool to improve QoL in BCS.

<i>Picassos Woman: A Breast Cancer Story</i> (1994) and <i>Ordinary Life: A Memoir of Illness</i> (1997) tell of the breast cancer experiences of Rosalind MacPhee and Kathlyn Conway, respectively. This thesis examines how three particular social movementsthe breast cancer, healthy-mindedness, and new momism movements, all described in Chapter Oneaffect how MacPhee and Conway experience breast cancer and then write about it in the 1990s. Chapter Two examines the language of war that MacPhee and Conway adopt to describe illness and how such language leads them to examine the possibility proposed by the healthy-mindedness movement: that they are personally responsible for bringing a determined killer (Conway 125) into their lives. Chapter Three studies their active patient behaviours, as advocated by the breast cancer movement, as well as their more passive ones. I consider the relation between these active and passive behaviours in light of the severe nature of mastectomies and the presentation of post-surgical options. Chapter Four investigates how MacPhee and Conway struggle to maintain their roles as supermoms, busily attending to responsibilities at home and work, while simultaneously managing their recoveries. In each Chapter, the influence of the social movements named above becomes apparent as MacPhee and Conway attempt to move themselves and others out of the breast cancer experience and back into a sense of normality (MacPhee 106).

<i>Picassos Woman: A Breast Cancer Story</i> (1994) and <i>Ordinary Life: A Memoir of Illness</i> (1997) tell of the breast cancer experiences of Rosalind MacPhee and Kathlyn Conway, respectively. This thesis examines how three particular social movementsthe breast cancer, healthy-mindedness, and new momism movements, all described in Chapter Oneaffect how MacPhee and Conway experience breast cancer and then write about it in the 1990s. Chapter Two examines the language of war that MacPhee and Conway adopt to describe illness and how such language leads them to examine the possibility proposed by the healthy-mindedness movement: that they are personally responsible for bringing a determined killer (Conway 125) into their lives. Chapter Three studies their active patient behaviours, as advocated by the breast cancer movement, as well as their more passive ones. I consider the relation between these active and passive behaviours in light of the severe nature of mastectomies and the presentation of post-surgical options. Chapter Four investigates how MacPhee and Conway struggle to maintain their roles as supermoms, busily attending to responsibilities at home and work, while simultaneously managing their recoveries. In each Chapter, the influence of the social movements named above becomes apparent as MacPhee and Conway attempt to move themselves and others out of the breast cancer experience and back into a sense of normality (MacPhee 106).

No description available.

Breast cancer is the most common malignancy in women and represents one of the major causes of death worldwide. The PI3K-Akt-FOXO3a signalling pathway has been shown to play a crucial role in tumorigenesis and the development of drug resistance in many cancer types. However, previous studies on FOXO3a using breast cancer tissues were controversial. So this study aims at better understanding of the role of FOXO3a in the development of drug resistance, especially endocrine resistance and anthracycline resistance in breast cancer. Examination of FOXO3a and phosphorylated-Akt (P-Akt) expressions in breast cancer tissue microarrays revealed nuclear FOXO3a was significantly associated with poor prognosis (p=0.014) and lymph node positivity (p=0.052) in invasive ductal carcinoma. Using the tamoxifen and anthracycline-sensitive and -resistant breast cancer cell lines as models, we found that the nuclear accumulation of FOXO3a was associated with enhanced anthracycline-resistance but not tamoxifen-resistance. This was consistent with the finding that sustained nuclear FOXO3a was associated with poor prognosis, as cytotoxic chemotherapy resistance is linked to limited therapeutic options and poor prognosis. We demonstrated a possible feedback mechanism in which induction of FOXO3a activity in the anthracycline-sensitive MCF-7 cells induced Akt phosphorylation and promoted cell proliferation arrest. Using MDA-MB-231-FOXO3a(A3):ER cells in which FOXO3a activity could be induced by 4-hydroxytamoxifen, we showed that FOXO3a induction could up-regulate PI3K-Akt activity but had little effect on cell proliferation, which indicates impaired Akt-FOXO3a axis in chemoresistant cell models. To further uncover the precise mechanism of Akt-FOXO3a deregulation in the development of chemoresistance, we have explored the post-translational regulation of FOXO3a by miRNAs. Through a series of Gain-and-Loss functional experiments and luciferase reporter assays in vitro, three miRNAs, including miR-222, miR-221 and miR-29a, were found to suppress FOXO3a protein expression through binding directly to FOXO3a 3’UTR. Moreover, the aberrant expressions of the miR-222/221 cluster and miR-29a in drug resistant cell lines could confer a proliferation advantage to cancer cells through suppressing FOXO3a expression. We further demonstrated that FOXO3a as a transcription factor could transactivate the oncogenic miR-222 and miR-221 expressions under certain chemotherapy stimulation. This suggests the existence of a feedback regulatory loop composed of the miR-222/221 cluster and FOXO3a which may not only play a self-protective role under drug treatment in chemosensitive cells, but also partially explain the tolerated nuclear FOXO3a in the breast cancer with poor prognosis. Taken together, our study suggested that lymph node metastasis and poor survival in invasive ductal breast carcinoma are linked to an uncoupling of the Akt-FOXO3a signalling axis, as in these breast cancers the nuclear-located FOXO3a was unable to induce cell death or cell cycle arrest. We also demonstrated post-translational regulation of FOXO3a by miR-222/221 and miR-29a, while aberrant expressions of miR-222/221 and miR-29a may promote cell resistance to therapy through directly suppressing FOXO3a. FOXO3a could further contribute to the deregulation of the miR-222/221 cluster as a transcription factor in breast cancer. Studying this Akt-FOXO3a-miRNAs signalling circuit will provide us better understanding in predicting and monitoring treatment response in breast cancer and other malignancies. / published_or_final_version / Pathology / Doctoral / Doctor of Philosophy