Digital Commons Network^™

Investigating Cellular Imaging Techniques For Cancer Cell Tracking, Natasha Knier

Electronic Thesis and Dissertation Repository

Introduction: Breast cancer remains a leading cause of mortality among women due to the propensity of breast tumours to spread and metastasize to distant sites, including the brain. Early detection of metastatic disease has been challenging, and typical methods of treatment often fail. A significant roadblock in advancing the detection and treatment of breast cancer brain metastases is the lack of representative experimental preclinical models and methods of studying its progression in vivo. Methods: First, we use iron-based cellular MRI to noninvasively track the progression of a brain metastatic breast cancer cell line in murine models with varying immune …

Quantitative Assessment Of Cardiac Functional Response After External Beam Radiotherapy Using Non-Invasive Multi-Modality Imaging, Oi Wai Chau

Electronic Thesis and Dissertation Repository

External beam radiation treatment is often included in standard breast cancer and non-small cell lung cancer patients’ curative management. With the advances in radiation treatment (RT) techniques, such as the development of intensity-modulated radiation therapy and volumetric modulated arc therapy, local and regional control benefits are established. However, both cancer type survivors are prone to develop radiation-induced cardiac disease in their cured life. Furthermore, our laboratory previously demonstrated an inflammatory response in canine models using ¹⁸FDG/PET imaging during the initial year following RT.

Hence, the overall goal of this thesis is to assess early functional changes and inflammation response …

Endothelial Cell-Specific Loss Of Breast Cancer Susceptibility Gene 2 Exacerbates Atherosclerosis, David C.R. Michels

Electronic Thesis and Dissertation Repository

Despite mounting concern over the increased risk of cardiovascular disease in breast cancer patients, studies evaluating the common genetic/molecular link between these diseases are limited. Mutations in the breast cancer susceptibility genes (BRCA1&2) predispose carriers to breast and ovarian cancers due to compromised DNA damage repair capacity leading to DNA damage accumulation; in cancer cells, and in other cell-types including endothelial cells, causing atherosclerotic hallmarks of endothelial dysfunction/apoptosis. We present a new understanding of BRCA2’s protective functionality in the setting of atherosclerosis. Studies have thus far demonstrated that while loss of endothelial BRCA2 in mice does not affect a molecular …

Investigating The Mechanisms Of Breast Cancer Metastasis Using Multimodality Molecular Imaging, Katie Parkins

Electronic Thesis and Dissertation Repository

Introduction: Breast cancer recurrence continues to be a significant challenge in the clinic. Despite successful removal and/or treatment of the original tumour, many patients experience relapse in the breast or at distant sites. Furthermore, the diagnosis of metastatic disease often occurs too late for effective treatment. Methods: In this thesis, we combine iron-based cellular MRI and longitudinal BLI to noninvasively track the fate of cancer cells into overt tumours in the mouse brain. We then apply this imaging model to study the effect of a primary breast tumour on the growth of secondary metastases in an immune competent …

In Vivo Tracking Of Tumour Associated Macrophages In Breast Cancer With Magnetic Resonance Imaging, Ashley V. Makela

Electronic Thesis and Dissertation Repository

Introduction: The environment in which a tumour exists and functions is called the tumour microenvironment (TME). In breast cancer, the presence of tumour associated macrophages (TAMs) in the TME is associated with tumour aggressiveness and poor outcomes. Despite evidence for a link between TAM content and outcome, there are few strategies to measure TAMs and no in vivo approach. Iron or fluorine-19 (¹⁹F)-based MRI can be used to detect macrophages post intravenous injection of either an iron or perfluorocarbon (PFC) agent. Iron-based MRI is sensitive but difficult to quantify. ¹⁹F MRI is specific and signal is proportional …

Lung-Derived Selectins Interact With Cd44 And Enhance The Migration Of Breast Cancer Cells, Sami U. Khan

Electronic Thesis and Dissertation Repository

The lung is among the deadliest sites of breast cancer metastasis. Previous work from our laboratory demonstrated that aggressive CD44-expressing breast cancer cells preferentially metastasize to the lung in vivo, and observed the presence of multiple CD44-interacting proteins in the lung including E-, L- and P-selectin. We hypothesized that lung-derived selectins promote breast cancer migration and/or growth via interactions with CD44. Using an ex vivo model of the soluble lung-microenvironment, we demonstrate that lung-derived selectins enhance in vitro migration but not proliferation of breast cancer cells. Co-immunoprecipitation experiments reveal that CD44 expressed by breast cancer cells in vitro interacts …

Space-Time Analysis Of Breast Cancer In Middlesex County Between 2003 And 2013, Jenny T. Tjhin

Electronic Thesis and Dissertation Repository

Breast cancer is the leading cancer among women in Canada and the incidence rate continues to increase despite improved screening programs and advanced cancer treatments. Some studies have linked breast cancer with risk factors such as genetics, the age of first menstruation, parity, and environmental exposures. This study investigated the spatial distribution of breast cancer cases between 2003 and 2013 in Middlesex County using geospatial techniques. Point data were analyzed with SaTScan and aggregated data were observed at two geographical units, census sub-divisions and dissemination areas using Moran’s Index to detect clusters. Both analyses showed consistency in the cluster locations …

Clinical And Genetic Predictors Of Aromatase Inhibitor-Induced Arthralgia, Adrienne Elizabeth Borrie

Electronic Thesis and Dissertation Repository

Aromatase inhibitors (AIs) are the most commonly used first-line endocrine treatment for postmenopausal women with estrogen receptor-positive breast cancer. Significant adverse drug reactions are associated with AIs, the most common being arthralgia. We hypothesized that a comprehensive assessment of pharmacogenetic and clinical variables that affect AI tolerability could improve AI selection and treatment for breast cancer patients. We recruited 196 patients diagnosed with breast cancer initiating AI therapy at the London Regional Cancer Program. Patients completed questionnaires regarding arthralgia symptoms and provided blood samples at baseline, 2 months and 6 months after AI initiation. Plasma letrozole drug concentration was measured …

Proteomic Characterization Of Ovarian And Breast Cancer Microenvironments For Improved Diagnostics And Therapeutic Targeting, Dylan Z. Dieters-Castator

Electronic Thesis and Dissertation Repository

Cancers exist within complex microenvironments formed by heterogeneous cell types. This diversity creates significant challenges for detection, diagnosis and treatment. Mass spectrometry-based proteomics is a powerful approach capable of characterizing complex biological systems which are characteristic of cancer biology. In this thesis, proteomics was utilized to answer several questions related to ovarian cancer diagnosis and detection, and the effects of NODAL, an embryonic morphogen, on the breast cancer secretome and stromal cell recruitment. First, I compared multiple sample preparation techniques and found high-pH/low-pH fractionation to yield the greatest proteome coverage over commonly used approaches. Second, I compared the proteomes from …

Oncoplastic Surgery: Is It Time To Change? From Innovation To Adoption Using Mentorship Program, Eman Khayat

Electronic Thesis and Dissertation Repository

Oncoplastic surgery is considered the standard of care for breast cancer therapy in numerous Western World countries, particularly in Europe. Despite the advancement of knowledge, Canada still lags in adoption of oncoplasty into the standard surgical practice. In our study, a mentorship program was used to introduce oncoplastic surgery to practicing breast surgeons at LHSC. The change in perception and adoption of oncoplastic surgery were evaluated using semi-structured interviews, before and after the intervention, by qualitative thematic analysis method. Mentorship program was validated as a superior method of learning new surgical techniques by practicing surgeons, demonstrating acceptance of different levels …

Influence Of The Metastatic Microenvironment On Stem-Like Human Breast Cancer Cells, Ashkan Sadri

Electronic Thesis and Dissertation Repository

Ninety percent of breast cancer-related mortalities result from metastasis. We have previously demonstrated that stem-like ALDHhiCD44+ breast cancer cells are critical for metastasis, and preferentially target the lung and bone marrow (BM). We hypothesize organ tropism occurs through promotion of the ALDHhiCD44+ phenotype. Using a 2D ex vivo model, lung and BM conditioned media (CM) were utilized to assess their influence on stem-like phenotype and behavior. Exposure of human breast cancer cells to lung-CM significantly decreased the proportion of cells with a stem-like ALDHhiCD44+ phenotype, decreased expression of cancer stem cell (CSC)-related genes, and increased gene expression related to migration …

Intraoperative Photoacoustic Imaging Of Breast Cancer, Ivan Kosik

Electronic Thesis and Dissertation Repository

Breast cancer is one of the most common cancers to affect women, presenting a lifetime risk of 1 in 8. Treatment of stage 1 and 2 cancers usually involves breast conserving surgery (BCS). The goal of BCS is to remove the entire tumour with a surrounding envelope of healthy tissue, referred to as a negative margin. Unfortunately, up to 50% of surgeries fail to remove the whole tumour. To minimize the risk of cancer recurrence, a second surgery, must therefore be performed. Currently, there is no widely accepted intraoperative tool to significantly mitigate this problem. Employed systems are usually based …

First-Order Statistical Speckle Models Improve Robustness And Reproducibility Of Contrast-Enhanced Ultrasound Perfusion Estimates, Matthew R. Lowerison

Electronic Thesis and Dissertation Repository

Contrast-enhanced ultrasound (CEUS) permits the quantification and monitoring of adaptive tumor responses in the face of anti-angiogenic treatment, with the goal of informing targeted therapy. However, conventional CEUS image analysis relies on mean signal intensity as an estimate of tracer concentration in indicator-dilution modeling. This discounts additional information that may be available from the first-order speckle statistics in a CEUS image. Heterogeneous vascular networks, typical of tumor-induced angiogenesis, lead to heterogeneous contrast enhancement of the imaged tumor cross-section.

To address this, a linear (B-mode) processing approach was developed to quantify the change in the first-order speckle statistics of B-mode cine …

Mt1-Mmp Mediates The Migratory And Tumourigenic Potential Of Breast Cancer Cells Via Non-Proteolytic Mechanisms, Mario Cepeda

Electronic Thesis and Dissertation Repository

Membrane Type-1 Matrix Metalloproteinase (MT1-MMP) is a multifunctional protease that affects cell function via proteolytic and non-proteolytic mechanisms such as promoting degradation of the extracellular matrix (ECM) or augmentation of cell migration and viability, respectively. MT1-MMP has been implicated in metastatic progression ostensibly due to its ability to degrade ECM components and to allow migration of cells through the basement membrane. Despite in vitro studies demonstrating this principle, this knowledge has not translated into the use of MMP inhibitors (MMPi) that inhibit substrate catalysis as effective cancer therapeutics, or been corroborated by evidence of in vivo ECM degradation mediated by …

Characterizing The Role Of The Neuropeptide Y-Y5r System In Breast Cancer, Jenna Kara

Electronic Thesis and Dissertation Repository

Studies have demonstrated a correlation between stress and an increased risk of breast cancer. Neuropeptide Y (NPY) is up- regulated in chronic stress and induces proliferation and chemotaxis of 4T1 breast cancer cells via Y5 receptor (Y5R) activation. In the studies performed in this thesis, we characterize NPY-Y5R as a regulatory system that promotes breast cancer metastasis. We compared three cancer cell sublines derived from the same murine mammary fat pad tumour, that greatly differ in metastatic potential (67NR, 168FARN, and 4T1) in addition to a 4T1-Y5R knockdown established in our labs. In this thesis we demonstrate significance of up-regulation …

Magnetic Resonance Imaging Of Breast Cancer Brain Metastasis Progression And Responses To Radiotherapy, Donna H. Murrell

Electronic Thesis and Dissertation Repository

Introduction: The incidence of brain metastasis due to breast cancer is increasing and prognosis is poor. Treatment is challenging for this disease because systemic therapy has limited efficacy due to the presence of the blood-brain barrier. In addition, it is thought that disseminated dormant cancer cells persist in metastatic organs and may evade treatment, thereby facilitating a mechanism for later recurrence. Methods: In this thesis, we use contrast-enhanced MRI and high resolution anatomical MRI to characterize blood-brain barrier integrity associated with the development of brain metastases due to HER2+ breast cancer in the SUM-190-BR3, JIMT-1-BR3, and MDA-MB-231-BR-HER2 experimental models. We …

Non-Invasive Imaging For The Assessment Of Cardiac Dose And Function Following Focused External Beam Irradiation, Omar El-Sherif

Electronic Thesis and Dissertation Repository

Technological advances in imaging and radiotherapy have led to significant improvement in the survival rate of breast cancer patients. However, a larger proportion of patients are now exhibiting the less understood, latent effects of incidental cardiac irradiation that occurs during left-sided breast radiotherapy. Here, we examine the utility of four-dimensional computed tomography (4D-CT) for the accurate assessment of cardiac dose; and a hybrid positron emission tomography (PET) magnetic resonance imaging (MRI) system to longitudinally study radiation-induced cardiac effects in a canine model.

Using 4D-CT and deformable dose accumulation, we assessed the variation caused by breathing motion in the estimated dose …

Characterization Of Microbial Communities In The Mammary Glands And The Influence Of This Microbiota On Health And Disease, Camilla Urbaniak

Electronic Thesis and Dissertation Repository

The collective microbes and their genomic activity within us, referred to as the human microbiome, is crucial in maintaining health, and disruptions in composition and activity have been associated with various diseases. Considering the importance of breast milk in neonatal development and the high rate of breast cancer in women, the objective of my thesis was to obtain a comprehensive analysis of the microbiota of the mammary glands and to examine the influence of these organisms on health and disease.

Human milk is an important source of bacteria for the developing infant. While a variety of studies over the last …

Interpretation Of Mutations, Expression, Copy Number In Somatic Breast Cancer: Implications For Metastasis And Chemotherapy, Stephanie Dorman

Electronic Thesis and Dissertation Repository

Breast cancer (BC) patient management has been transformed over the last two decades due to the development and application of genome-wide technologies. The vast amounts of data generated by these assays, however, create new challenges for accurate and comprehensive analysis and interpretation. This thesis describes novel methods for fluorescence in-situ hybridization (FISH), array comparative genomic hybridization (aCGH), and next generation DNA- and RNA-sequencing, to improve upon current approaches used for these technologies. An ab initio algorithm was implemented to identify genomic intervals of single copy and highly divergent repetitive sequences that were applied to FISH and aCGH probe design. FISH …

The Role Of Cytoplasmic Polyadenylation Element Binding Protein-2 (Cpeb-2) In Breast Cancer, Asma Hasan

Electronic Thesis and Dissertation Repository

Over-expression of inflammation associated enzyme cyclo-oxygenase (COX)-2 promotes breast cancer progression, metastasis and sustains cancer stem-like cells (SLCs) by activating prostaglandin E₂ receptor EP4. Two COX-2 induced oncogenic miRNAs, miR-655 and miR-526b, target and down-regulate the cytoplasmic polyadenylation element binding protein (CPEB)-2. Hypothesis: Down-regulation of CPEB2 promotes an aggressive breast cancer phenotype through SLC induction and epithelial to mesenchymal transition (EMT). We found that high COX-2/miRNA expressing cell lines MDAMB231 and MCF7-COX-2 had significantly lower expression of CPEB2 than MCF7 cells (low COX-2/miRNA). CPEB2 knockdown in CPEB2-high MCF7 cell line resulted in increased migratory and invasive capacity in …

The Role Of Connexins And Pannexins In Mammary Gland Development And Tumorigenesis, Michael K. G. Stewart

Electronic Thesis and Dissertation Repository

The identification of key regulators of breast cancer onset and progression is critical for the development of targeted therapies. Connexins and pannexins are characterized by their ability to form large-pore channels and are frequently dysregulated in cancer. However, their role in breast cancer progression remains poorly understood due to a lack of in vivo models capable of assessing the proposed and opposing roles of connexins and pannexins as both tumor suppressors and/or facilitators in multiple stages of the disease. Using 2 previously uncharacterized genetically-modified mice, connexin43 (Cx43) and connexin26 (Cx26) were evaluated for their role in normal mammary gland development …

The Lung Microenvironment Influences The Metastatic Behaviour Of Breast Cancer Cells In An Innovative 3d Ex Vivo Pulmonary Metastasis Model, Matt M. Piaseczny

Electronic Thesis and Dissertation Repository

Lung metastasis remains a leading cause of death in breast cancer patients. This study established an innovative 3D ex vivo pulmonary metastasis assay (PuMA) to test the hypothesis that the lung microenvironment promotes metastatic behaviour of whole population and stem-like ALDH^hiCD44⁺ breast cancer cells. Following in vivo delivery of breast cancer cells to mice, lungs were excised, maintained in culture and imaged to observe breast cancer growth over time. We observed metastatic progression of breast cancer cells in the PuMA, most notably of ALDH^hiCD44⁺ cells which progressed rapidly from single cells to multicellular colonies …

The Role Of Bone-Derived Osteopontin In The Migration And Stem-Like Behavior Of Breast Cancer Cells, Graciella Pio

Electronic Thesis and Dissertation Repository

The majority of breast cancer deaths occur due to metastasis, with the most common site of breast cancer metastasis being bone. Previous work in our laboratory has established that stem-like breast cancer cells with high aldehyde dehydrogenase (ALDH) activity and expression of a CD44⁺CD24^- phenotype have enhanced metastatic capacity. This study tested the hypothesis that bone-derived osteopontin (OPN) promotes the migration and stem-like behavior of breast cancer cells. We demonstrate that bone- derived OPN promotes migration, tumorsphere-forming ability and colony-forming ability of whole population and ALDH^hiCD44⁺CD24^- breast cancer cells in bone marrow- …

The Role Of Mir-526b In Cox-2 Mediated Human Breast Cancer Progression And Induction Of Stem-Like Phenotype Via Ep4 Receptor Signaling, Erin O. Landman

Electronic Thesis and Dissertation Repository

Our laboratory previously established that aberrant expression of cyclo-oxygenase (COX)-2 promotes breast cancer progression and metastasis via multiple mechanisms, including stem-like cell (SLC) induction, owing to activation of the prostaglandin E2 receptor EP4. COX-2 expression was linked to up-regulation of miRNA-526b. We hypothesized that miR-526b is regulated by EP4 activity, and that miR-526b supports breast cancer progression and induction of SLCs. Using stably miR-526b transfected MCF-7 and SKBR-3 cells in functional assays, including tumorsphere formation in vitro and lung colony formation in vivo, we observed enhanced migration, invasion, proliferation, tumorsphere formation, and in vivo tumorigenecity compared to controls. EP4 …

The Synthesis And Evaluation Of Peptide-Based Probes For The Imaging Of Rhamm Expressing Carcinoma And Glp-1r On Pancreatic Beta Cells, Ashley Esarik

Electronic Thesis and Dissertation Repository

Peptide-based probes are developed into imaging agents to target two different receptors: receptor for HA mediated motility (RHAMM) and glucagon-like peptide 1 receptor (GLP-1R).

In the first project, peptides are derived from tubulin and mimic HA (hyaluronan), the natural ligand of RHAMM. In order to develop the lead candidate peptides into imaging agents, a DOTA chelator which can coordinate a radiometal was coupled onto the lead peptides. Gallium labelling studies were performed and the labelled probes were used in in vivo mouse studies. Various analogues of two of the candidate peptides were also synthesized using bioisosteric, unnatural as well as …

The Impact Of The Neuropeptide Y System On The Progression Of Breast Cancer, Philip J. Medeiros

Electronic Thesis and Dissertation Repository

Chronic stress is associated with elevated levels of sympathetic neurotransmitter release and immunosuppression. A growing body of evidence suggests that stress-related factors may contribute to the initiation, development and progression of breast cancer. Neuropeptide Y (NPY) has recently been determined as such a factor, however few investigations have addressed the functional effects of NPY on breast cells and tumors. Thus, the overall objective of this thesis was to elucidate the mechanisms by which NPY may contribute to the disease. Using the 4T1 murine breast cancer model, we began by first characterizing NPY receptor expression in cancer cells and tumors. Y1R, …

Kiss1r Induces Human Mammary Epithelial Cell Invasiveness And Promotes Breast Cancer Cell Migration And Invasion Via Iqgap1, Donna Cvetkovic

Electronic Thesis and Dissertation Repository

Kisspeptins (KP), peptide products of the kisspeptin-1 (KISS1) gene are the endogenous ligands for a G protein-coupled receptor (KISS1R). KISS1 acts as a metastasis suppressor in numerous human cancers. However, recent studies have demonstrated that an increase in KISS1 and KISS1R expression in human breast tumors correlates with higher tumor grade and metastatic potential. We have previously shown that KP-10, the most potent KP, stimulates invasion of estrogen receptor (ER)-negative breast cancer cells via transactivation of the epidermal growth factor receptor (EGFR). Here, I report that KP-10 treatment of the ER-negative non-malignant mammary epithelial MCF10A cells, or stable …

The Embryonic Protein Nodal Supports Metastatic Phenotypes In Breast Cancer, Daniela F. Quail

Electronic Thesis and Dissertation Repository

Metastasis is the process by which tumour cells disseminate to distant organ sites. Aberrant expression of stem cell-associated proteins within tumours is associated with metastasis and poor patient prognosis. One example of a stem cell factor that is associated with cancer progression is Nodal, a member of the TGF-β superfamily. Nodal is normally limited to pluripotent stem cells during embryonic development, and to specialized dynamic adult tissue (such as the cycling endometrium), but is aberrantly re-expressed in multiple cancer types, including melanoma, glioma, prostate cancer, and pancreatic cancer. The central objective of this thesis is to determine the role of …

Functional Role Of Aldehyde Dehydrogenase-1a1 (Aldh1a1) In Breast Cancer Metastatic Behaviour, Irene Ngai Ki Ma

Digitized Theses

Previous work in our lab indicates “stem-like” breast cancer cells can be identified by an ALDHhlCD44+phenotype and that these cells are significantly more metastatic than ALDHlowCD44‘cells. The purpose of this project was to investigate the functional role of overexpressed human ALDH1A1 in breast cancer behaviour. ALDH1A1 was stably overexpressed in MCF-7 human breast cancer cells and these cells were assessed using functional in vitro assays of metastasis (proliferation, adhesion, migration, colony formation). Despite overexpression of ALDH1A1, no significant differences were observed in malignant cell behaviour between empty vector control and MCF- 7/ALDH1A1 cells. However, it was observed that MCF-7/ALDH1A1 cells …

Quantitative Analysis Of Dynamic Contrast-Enhanced Magnetic Resonance Breast Images: Optimization Of The Time-To-Peak As A Diagnostic Indicator, Fang Liu

Digitized Theses

Dynamic contrast-enhanced MRI (DCE-MRI) has been widely used in the diagnosis of breast cancer and as an aid in the management of this disease. Although DCE-MRI has a high sensitivity for the detection of malignant breast lesions, distinguishing malignant from benign lesions is more challenging for this method and may depend to some extent on how the images are analysed. Although clinical assessment of these images typically involves qualitative assessment by an expert, there is growing interest in the development of quantitative and automated methods to assist the expert assessment. This thesis involves the quantitative analysis of a particular empirical …