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Reconstructing Mutational Lineages In Breast Cancer By Multi-Patient-Targeted Single Cell Dna Sequencing, Jake Leighton

Dissertations & Theses (Open Access)

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with high rates of metastasis and recurrence, where TNBC patients have a poor 5-year survival and ~50% are non-responsive to chemotherapy. Aneuploidy is a cancer hallmark that is pervasive in over 90% of breast cancer patients and is indicative of complex genomic rearrangements that are acquired during tumor initiation. Although copy number aberrations have been extensively studied in relation to aneuploidy and TNBC initiation, little is currently known regarding the timing and impact of single nucleotide variants (SNVs) contributing to these early transformative genomic events. Paramount to novel …

Low Molecular Weight Cyclin E Deregulates Dna Replication And Damage Repair To Promote Genomic Instability In Breast Cancer, Mi Li

Dissertations & Theses (Open Access)

Low molecular weight cyclin E (LMW-E) are oncogenic forms of cyclin E that are post translationally generated by neutrophil elastase (NE) mediated cleavage of the 50 KDa full-length cyclin E1 (FL-cycE, encoded by CCNE1gene). The resultant N-terminus deleted (40 amino acids) form of LMW-E is detected in breast cancer cells and tumor tissues, but not in normal mammary epithelial cells or adjacent normal tissues. Unlike FL-cycE, LMW-E drives mammary epithelial cell transformation in human cells and spontaneous mammary tumor formation in transgenic mouse models, but the oncogenic mechanisms of LMW-E and its unique function(s) independent of FL-cycE are not …

Decoding The Tumor And Immune Microenvironment In Pdac And Breast Cancer By Single Cell Sequencing., Aislyn Schalck

Dissertations & Theses (Open Access)

This work utilizes single cell RNA sequencing to identify transcriptional populations and gene changes for the purpose of immune-related cancer therapies. First we have characterized the T cell populations of the normal and malignant human pancreas. Furthermore, we utilized single cell TCR sequencing to track transcriptional states of T cell clones from human PDACs into a T cell culture product for adoptive cell therapy. Second, we examined the potential role of radiotherapy in inducing an immune response in hormone receptor positive breast tumors.

Integrin-Mediated Mechanotransduction Controls Activation Of Yap And Invasive Growth Of Breast Cancer, Xiaobo Wang

Dissertations & Theses (Open Access)

Tumor extracellular matrix (ECM) stiffness is correlated with the aggressiveness of breast cancer. Integrin-mediated adhesion and signaling are crucial for mammary tumorigenesis and tumor progression, in which focal adhesion kinase (FAK) - Src family kinases (SFKs) serves as a hub to relay the mechanical cues from the ECM. We have investigated the mechanisms through which integrin signaling controls mammary tumorigenesis and found that integrin-mediated mechanotransduction controls invasive growth of breast cancer cells in stiff matrices through activation of FAK and YAP. Mechanistic studies revealed that integrin signaling induces - via activation SFKs - tyrosine phosphorylation and inactivation of LATS1 and …

Understanding The Role Of Arglu1 In Interferon Signaling Activation In Breast Cancer, Phuoc Nguyen

Dissertations & Theses (Open Access)

In the U.S., the highest number of new cancer cases belongs to breast cancer in women, and this cancer also bears the second-highest death rate in women. Despite significant progress in breast cancer treatment that has been made in the past several decades, innovative and efficient therapies are still needed to eradicate this deadly disease. Novel cancer immunotherapy with immune checkpoint blockade (ICB) could induce long-lasting responses and improve survival in hard-to-treat malignancies. Regrettably, only a fraction of breast cancer patients respond to this highly promising strategy. To improving ICB therapy in breast cancer treatment, IFN signaling induction is a …

Assessing The Outcomes Of Blocking Ccl2-Ccr2 Signaling Axis On Breast Cancer Brain Metastasis, Yutao Qi

Dissertations & Theses (Open Access)

Breast cancer brain metastases have remained one of the most intense challenges for precision cancer therapeutics, but current treatment options are limited and not curative. Recently, our lab reported that adoptive PTEN downregulation in metastatic breast tumor cells activates PI3K/NF-ƙB signaling and increases the secretion of the chemokine CCL2, which enhances the chemotaxis of CCR2⁺ myeloid cells, a major subpopulation of bone marrow-derived myeloid cells (BMDMs), from peripheral blood into the brain tumor microenvironment (TME), eventually promoting brain metastasis outgrowth by driving immune suppression. Here, in this project we have been aiming to develop effective therapies by immune-modulating the …

Deubiquitinating Enzymes Promote Cancer Progression And Metastasis Via Regulating Protein Stability, Zhenna Xiao

Dissertations & Theses (Open Access)

Deubiquitinating enzymes (DUBs, also called deubiquitinases) are enzymes that remove monoubiquitin or polyubiquitin chains from target proteins. DUBs have critical roles in cell homeostasis and signal transduction, as they regulate protein degradation, subcellular localization, and protein-protein interaction. Deregulation of DUBs contributes substantially to tumor formation and progression, and therefore targeting DUBs may be a promising cancer therapy strategy. My dissertation focuses on identifying the DUBs of EZH2 and SNAI1, two proteins critical for cancer progression and metastasis, and establishing these DUBs as promising anti-cancer targets.

EZH2, the catalytic component of the PRC2 complex, silences gene transcription by histone methylation. High …

Gcn5 Loss Impacts Myc-Driven Cancer In Mice And Human Cells, Aimee Farria

Dissertations & Theses (Open Access)

GCN5 is the catalytic subunit in the acetyltransferase module of SAGA and ATAC, multiprotein complexes involved in the modification of histone and nonhistone proteins. GCN5 is most recognized as a co-activator of gene transcription. The SAGA complex is recruited to chromatin by transcription factors such as MYC and E2F1 where GCN5 acetylates H3K9 leading to a more open and accessible chromatin structure. Previous research has demonstrated that GCN5 also acetylates MYC, a protein that amplifies the expression of cancer-promoting genes and is frequently dysregulated in cancer, increasing its stability. Our lab has found there is a significant overlap in the …

The Role Of Tumor Suppressor Dear1 In The Acquisition Of Mammary Stem/Progenitor Cell Properties, Uyen Le

Dissertations & Theses (Open Access)

Breast cancer is the most commonly diagnosed cancer in women in America. Ductal carcinoma in situ (DCIS), one of the earliest pre-invasive forms of invasive ductal carcinoma (IDC), has a 30-50% risk of progressing to IDC. Understanding the mechanisms regulating progression from DCIS to IDC would help identify biomarkers to stratify patients at higher risk of progression or metastasis. Cumulative literature suggests the earliest phase of dissemination from the primary tumor is driven by the epithelial-mesenchymal transition (EMT) program. DEAR1 is a tumor suppressor gene which is mutated, undergoes loss of heterozygosity in breast cancer, and is downregulated in DCIS …

Investigating Invasion In Ductal Carcinoma In Situ With Topographical Single Cell Genome Sequencing, Anna Casasent, Anna Casasent

Dissertations & Theses (Open Access)

Synchronous Ductal Carcinoma in situ (DCIS-IDC) is an early stage breast cancer invasion in which it is possible to delineate genomic evolution during invasion because of the presence of both in situ and invasive regions within the same sample. While laser capture microdissection studies of DCIS-IDC examined the relationship between the paired in situ (DCIS) and invasive (IDC) regions, these studies were either confounded by bulk tissue or limited to a small set of genes or markers. To overcome these challenges, we developed Topographic Single Cell Sequencing (TSCS), which combines laser-catapulting with single cell DNA sequencing to measure genomic copy …

Deciphering The Roles Of Δnp63 In Regulating Epithelial To Mesenchymal Transition, Cancer Progression And Metastasis, Ngoc Bui

Dissertations & Theses (Open Access)

p63 is a member of the p53 family, a well-known tumor suppressor which is considered the guardian of the genome. The TP63 gene encodes multiple isoforms that can be categorized into two main isoforms, TAp63 and ΔNp63, which are expressed in different cellular compartments and have distinct functions in many biological processes. While the Flores laboratory identified TAp63 as a tumor and metastasis suppressor, the precise roles of ΔNp63 isoforms in tumorigenesis and metastasis remain elusive. ΔNp63 is the predominant p63 isoform expressed in the epidermis and plays essential roles in regulating epidermal development and homeostasis. Utilizing a ΔNp63-conditional …

Cytoplasmic Cyclin E Mediates Resistance To Aromatase Inhibitors In Breast Cancer, Iman Doostan

Dissertations & Theses (Open Access)

Almost seventy percent of patients with breast cancer have tumors that express hormone receptors and need hormonal therapy. Aromatase inhibitors (AIs) block estrogen biosynthesis and are considered as the first line hormonal therapy for ER⁺ post-menopausal patients. However, resistance to these drugs remains a major challenge in clinic and the biology of such resistance is not completely understood. Cyclin E is deregulated in breast cancer through generation of low molecular weight isoforms that renders patients to a poor survival. Herein, we show that HR+ patients with LMW-E expressing tumors show diminished early response to neo-adjuvant AIs as well as …

Targeting Autophagy To Improve Efficacy Of Cdk4/6 Inhibition In Breast Cancer, Smruthi Vijayaraghavan

Dissertations & Theses (Open Access)

Deregulation of the cell cycle machinery is a hallmark of cancer, leading to aberrant proliferation and tumorigenesis. The crucial role of the CDK4/6-Cyclin D pathway has led to the development and FDA approval (palbociclib, ribociclib) of CDK4/6 inhibitors for the treatment of advanced estrogen receptor positive breast cancer. However, three major clinical challenges remain: i) adverse events leading to discontinuation of therapy and ii) lack of reliable biomarkers to identify responsive patients and iii) acquired resistance to CDK4/6 inhibitors. Previous in vitro studies have shown that palbociclib mediated CDK4/6 inhibition induces G1 arrest and senescence in ER+ breast cancer cells, …

Investigating The Roles Of Δnp63 As A Suppressor Of Migration, Invasion, And Metastasis, Ramon E. Flores Gonzalez

Dissertations & Theses (Open Access)

Cancer is one of the leading causes of death and disease in the world. Considerable resources are spent to study and understand cancer, with the hope of developing new treatments and eventually cures that will help millions of people. Efforts to understand cancer are hindered by its inherent complexity and instability. Nonetheless, understanding the basics of tumor development and progression are the key to focused on studying the role of ΔNp63 in cancer, a p53 family member known to be involved in epithelial development, microRNA biogenesis, and stem cell maintenance. Using the strength of in vivo mouse models, we found …

Trim24 Orchestrates Metabolic Reprogramming And Emt In Breast Cancer, Kaushik Thakkar

Dissertations & Theses (Open Access)

In this dissertation, I report the oncogenic functions of an epigenetic regulator Tripartite Motif Protein 24 (TRIM24) coupled with metabolic reprogramming and epithelial mesenchymal transition (EMT) in breast cancer. TRIM24 was first established by our laboratory as a previously unknown negative regulator of p53 via its RING domain, as a co-regulator of nuclear receptors and a PHD/Bromodomain reader of specific histone modifications. TRIM24 expression correlates with poor prognosis of breast cancer, but the mechanisms of TRIM24-mediated oncogenesis are unknown. In the first part of my thesis, I found that TRIM24 is aberrantly expressed in early stages of breast cancer progression. …

The Role Of Amp-Activated Protein Kinase (Ampk) In Tumorigenesis, Fei Han

Dissertations & Theses (Open Access)

AMPK plays a central role in controlling cellular and whole body energy level. Increasing studies have also discovered the diverse function of AMPK in cancer, such as autophagy and mitochondria biogenesis. However, how AMPK promotes cancer progression is still not clear. Here, we show that AMPK is essential for EGF-induced Akt activation, Glut1 expression, and glucose uptake. AMPK is also required for various stresses induced Akt activation and promote cell survival, including hypoxia and glucose deprivation. In addition, we found glucose deprivation-induced VEGF expression and secretion is also depend on AMPK, which may contribute to angiogenesis of surrounding endothelial cell …

Rerouting Pre-Existing Host Vaccine-Induced Immunity Towards Breast Cancer, Bharat Kumar Reddy Chaganty

Dissertations & Theses (Open Access)

For decades, investigators have attempted to activate the immune system to prevent cancer metastasis or recurrence; however, owing to host immune tolerance to cancer antigens and the immunosuppressive environment at tumor sites, many such attempts have failed. The recent success of anti-CTLA4, PD-L1 and PD-1 antibodies targeting immune checkpoint pathways and HPV vaccines has renewed hope that patient survival can be increased through enhancing T-cell responses. We propose to test a novel approach that may bypass host immune tolerance to cancer cells. We hypothesize that host T-cell immunity acquired through vaccination against or natural infection with infectious diseases—e.g., influenza—can be …

Prophylactic Cranial Irradiation Reduces The Incidence Of Brain Metastasis In A Mouse Model Of Metastatic Breast Cancer, Daniel L. Smith

Dissertations & Theses (Open Access)

Prophylactic cranial irradiation (PCI) is a preventative whole-brain irradiation technique used to reduce the incidence of brain metastasis and improve overall survival in select patients with small cell lung cancer and acute lymphoblastic leukemia. A population of breast cancer patients – stage IV, HER2+ or triple-negative – has emerged as having a high risk of developing brain metastases. Because only 10-20% of breast cancer patients diagnosed with brain metastases survive longer than one year, in this high-risk population the benefit of PCI – potential for reduced incidence of brain metastasis and improved overall survival – may outweigh the risks – …

Jab1 Negatively Regulates Pten And Promotes Resistance To Trastuzumab In Her2-Positive Breast Cancer, Thuy T. Vu

Dissertations & Theses (Open Access)

HER2-positive breast cancer, which is characterized by the over-expression of the HER2 onco-protein, accounts for approximately 20% of all breast cancer cases. Trastuzumab (Herceptin), the first targeted therapy approved for HER2-positive disease, potently prevents the activation of signaling pathways downstream of HER2 and significantly improves patients’ outcomes. However, resistance to trastuzumab is inevitable; such resistance can occur through reduced expression of PTEN protein.

Jab1 is over-expressed in 50% of primary cancers and 90% of metastatic tumors. Our lab previously showed that depletion of Jab1 in combination with trastuzumab treatment up-regulated PTEN in mouse xenografts refractory to trastuzumab. PTEN was not …

Mdm2-Mediated Degradation Of Sirt6 Phosphorylated By Akt1 Promotes Tumorigenesis And Trastuzumab Resistance In Breast Cancer, Umadevi Thirumurthi

Dissertations & Theses (Open Access)

Sirtuin6 (SIRT6) is one of the members of the Sirtuin family and functions as a longevity assurance gene by promoting genomic stability. It also regulates various cancer-associated pathways and was recently established as a bonafide tumor suppressor in colon cancer. This suggests that SIRT6 is an attractive target for pharmacological activation in cancer treatment, and hence, identification of potential regulators of SIRT6 would be an important and critical contribution towards cancer treatment. Here, we show that AKT1 phosphorylates SIRT6 at Ser³³⁸ and induces MDM2-SIRT6 interaction, priming SIRT6 for degradation via the MDM2-dependent ubiquitin-proteasome pathway. Blocking SIRT6 Ser³³⁸ phosphorylation …

Targeting Cox-2 And Rank In Aggressive Breast Cancers: Inflammatory Breast Cancer And Triple-Negative Breast Cancer, Monica E. Reyes

Dissertations & Theses (Open Access)

Inflammatory breast cancer (IBC) and triple-negative breast cancer (TNBC) are two highly aggressive breast cancer subtypes associated with a poor outcome. Despite sensitivity to current treatment, these breast cancers subtypes have a high recurrence rate and proclivity to metastasize early. The aggressiveness of IBC and TNBC have been linked to CSCs and epithelial to mesenchymal transition (EMT), which are critical features of breast cancer progression and metastasis. The clinical challenge faced in the treatment of IBC and TNBC is finding a treatment strategy to target the cancer stem-like (CSC) population to block metastasis. Cyclooxygenase-2 (COX-2) and receptor activator of nuclear …

Nuclear Translocation Of Met Via Internet Mechanism, Mei-Kuang Chen

Dissertations & Theses (Open Access)

MET is one of the receptor tyrosine kinases (RTKs) that are overexpressed in malignant cancer types, including breast cancer. While RTKs are traditionally known for their roles in signaling transduction from the cell surface, recent studies have provided evidence demonstrating that most of RTKs can translocate into nucleus to regulate cellular processes in response to both ligand and stress stimulation. Oxidative stress is a common stress in cancer cells due to alteration of metabolism, and constitutive oxidative stress related to reactive oxygen species (ROS) has been observed in breast cancer cells. Here, we show that hepatocyte growth factor (HGF) as …

Brit1/Mcph1 Mediates The Dna Damage Response By Inducing P53 Stability And Promoting Atr Signaling, Edward Wang

Dissertations & Theses (Open Access)

The BRCT-repeat inhibitor of hTERT (BRIT1)/MCPH1 protein promotes the process of homologous recombination (HR) to repair DNA double strand breaks (DSBs). In response to DSBs, BRIT1 foci form at damaged sites, and recruits downstream repair proteins including 53BP1, MDC1, NBS1, and the SWI/SNF complex to the DSB region to promote DNA repair. BRIT1 copy number deficiency correlates with increased genomic instability in ovarian cancer specimens and breast cancer cell lines. Here, we propose that additional functions of BRIT1 include a direct interaction with the p53 tumor suppressor protein to promote p53 stability, and binding and recruitment of TopBP1 to sites …

Anti-Insulin Resistance Treatments Suppress Her2+ Breast Cancer Growth Via Altering Metabolism, Ping-Chieh Chou

Dissertations & Theses (Open Access)

Epidemiological studies have identified that type 2 diabetes mellitus (DM2) is a significant risk factor for carcinogenesis and cancer death, including breast cancer. Our previous finding in patients showed that anti-insulin resistance treatments are associated with improved HER2⁺ breast cancer survival of diabetic women. However, there were no transgenic mouse models to study the correlation and explain the detailed mechanism. We generated a mouse model of HER2⁺ breast cancer with DM2 by crossing leptin receptor point mutation (Lepr ^db/+) and MMTV-ErbB2 (neu) mice. The MMTV-ErbB2/Lepr ^db/db mice had a poor survival rate compared …

The Regulation Of Microrna Biogenesis By Ribosome-Interacting Proteins, Brian Pickering

Dissertations & Theses (Open Access)

MicroRNA (miRNA) are small, non-coding RNAs that affect gene expression through degradation of complementary mRNA targets or inhibition of translation. As they affect approximately 50% of all cellular processes, miRNA are tightly regulated by the cell through transcriptional and post-transcriptional mechanisms. Transcribed miRNA are capped and polyadenylated (referred to as pri-miRNA) which are cleaved by Drosha and DGCR8 to generate 60-90 nucleotide precursor miRNA. The precursors are cleaved again by Dicer and loaded into the RNA-induced silencing complex (RISC) of which Argonaute 2 is the functional component. Many of the proteins involved in miRNA biogenesis share a common role in …

Regulation Of Mammary Gland Development And Tumorigenesis By 14-3-3 Zeta, Sumaiyah Rehman

Dissertations & Theses (Open Access)

Signaling pathways that play critical roles in organ development are often aberrantly regulated during cancer initiation and progression. 14-3-3z is overexpressed in more than 40% of breast cancers and is associated with poor patient prognosis. Therefore, the function of 14-3-3z in cancer and normal mammary gland development was investigated utilizing multiple in vivo and in vitro approaches. 14-3-3z is a chaperone protein that interacts with a multitude of oncogenes and tumor suppressor genes, thereby functioning as a critical node in multiple oncogenic signaling networks. Mammary gland-specific 14-3-3z transgenic mouse models showed that 14-3-3z overexpression was sufficient to induce mammary tumorigenesis. …

Ezh2 T416 Phosphorylation Enhances Breast Cancer Tumorigenesis, Adam M. Labaff, Adam M. Labaff

Dissertations & Theses (Open Access)

Enhancer of zeste homologue 2 (EZH2) is the catalytic subunit of Polycomb repressive complex 2 (PRC2) and catalyzes the trimethylation of histone H3 on lysine 27 (H3K27Me3), to repress gene transcription. Many types of cancer stem and progenitor cells, including breast, have demonstrated EZH2 to be fundamental in the biology and promoting the expansion of their cellular populations. How EZH2 regulates each of these respective tumor initiating cells (TICs) populations has been studied, but the signaling transduction mechanisms that regulate EZH2 in these TIC populations is yet to be elucidated. Phosphorylation of EZH2 by cyclin dependent kinases (CDK) has been …

Interaction Between Brk And Her2 In Breast Cancer, Midan Ai

Dissertations & Theses (Open Access)

INTERACTION BETWEEN BRK AND HER2 IN BREAST CANCER

Midan Ai, Ph.D.

Supervisory Professor: Zhen Fan, M.D.

Breast tumor kinase (Brk) is a nonreceptor protein-tyrosine kinase that is highly expressed in approximately two thirds of breast cancers but is not detectable or is expressed at very low levels in normal mammary epithelium. Brk plays important roles in promoting proliferation, survival, invasion, and metastasis of breast cancer cells, but the mechanism(s) of which remain largely unknown. Recent studies showed that Brk is frequently co-overexpressed with human epidermal growth factor receptor-2 (HER2) and is physically associated with HER2 in breast cancer. The mechanism …

The Role Of Type I Insulin-Like Growth Factor Receptor Signaling In Breast Cancer Brain Metastasis, Sandra M. Saldana

Dissertations & Theses (Open Access)

Brain metastasis is a common cause of mortality in cancer patients. Approximately 20-30% of breast cancer patients acquire brain metastasis, yet potential therapeutic targets remain largely unknown. The type I insulin-like growth factor receptor (IGF- IR) is known to play a role in the progression of breast cancer and is currently being investigated in the clinical setting for various types of cancer. The present study demonstrates that the IGF-IR signaling axis is constitutively active in brain-seeking sublines of breast cancer cells, driving an increase in in vitro metastatic properties. We demonstrate that IGF-IR signaling is activated in an autocrine manner …

Cellular Uptake Of Neutrohpil Elastase Links Inflammation To Adaptive Immunity, Elizabeth A. Mittendorf

Dissertations & Theses (Open Access)

Many tumors arise from sites of inflammation providing evidence that innate immunity is a critical component in the development and progression of cancer. Neutrophils are primary mediators of the innate immune response. Upon activation, an important function of neutrophils is release of an assortment of proteins from their granules including the serine protease neutrophil elastase (NE). The effect of NE on cancer has been attributed primarily to its ability to degrade the extracellular matrix thereby promoting invasion and metastasis. Recently, it was shown that NE could be taken up by lung cancer cells leading to degradation of insulin receptor substrate-1 …