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1رسالة جامعية
المؤلفون: Sánchez-Lorenzo, M. L. (María Luisa)
الملخص: Objective: Metastatic HER2-positive breast cancer remains a significant clinical challenge with a poor prognosis. The introduction of anti-HER2 therapies has significantly improved survival in early and advanced stages. However, patients with metastatic HER2-positive breast cancer eventually experience progression due to de novo or acquired resistance. This review article comprehensively analyzes the current management of metastatic HER2-positive breast cancer, addressing the complexities in determining the optimal HER2-targeted therapy sequence. Data Sources: Discussion of selected peer-reviewed articles and expert opinion. Conclusions: We explore the actual standard of care and the emerging therapeutic options that hold promise for further improving patient care and survival in this aggressive breast cancer subtype. This article highlights vital toxicities linked to anti-HER2 therapies, emphasizing their recognition across treatments as interstitial lung disease, diarrhea, or left ventricular dysfunction. Implications for Nursing Practices: Oncology nurses have a key role to play in detecting potential adverse effects of anti-HER2 therapies. The development of new drugs, as antibody drug conjugates, with a distinct toxicity profile makes it necessary for us to be updated on the management of these new toxicities.
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2رسالة جامعية
المؤلفون: Tallman, David
Advisors: Stover, Daniel
الملخص: The number of cancer diagnoses worldwide is on the rise as populations continues to grow older. In the US, the amount of money allocated to cancer research by the National Cancer Institute increases yearly. With increasing focus towards cancer research, it is important researchers maintain perspective and to ensure that these resources are utilized efficiently. The research mission of the Stover Lab is to improve the outcomes of patients with cancer. We keep the patients in mind during the entire research process, from project conception to publication. In this dissertation, three distinct research projects undertaken during my PhD are summarized. In Chapter 2, we investigated the survivorship needs of patients with gynecological cancers. By extracting posts made on the American Cancer Society’s Cancer Survivorship forums, we discovered some of the needs of cancer patients by looking at their posted conversations and concerns. We developed an analysis methodology to allow post extraction that pertain to custom themes. We showed its utility by extracting and qualitatively analyzing posts that pertain to the psychosocial aspects of survivorship. In Chapter 3, a novel image analysis-based algorithms were developed to investigate the patterns of expression of HER2 in breast cancer patients. Current treatment strategy for breast cancer is reliant on determining whether a patient is HER2 positive using a clinical immunohistochemistry stain for HER2. The criteria used by pathologists for this test is simplistic, in that it only looks at a proportion of intensely stained cells and uses a single cutoff to define a patient as HER2 positive or negative. We believe there is an opportunity to gather more information from these IHC stains and use this information to further delineate breast cancer patients based on their HER2 expression, better predicting patient outcomes. We showed a new method that quantifies the heterogeneity of HER2 expression and significantly predicted recurrence free survival in a cohort of HER2 positive breast cancer. We hope that this may be researched further and implemented into clinical practice, improving on a clinical test that is already being used worldwide. Lastly, in Chapter 4, we discussed the development of a bioinformatics tool that discovers and quantifies the existence of patterns in copy number profiles of cancer samples. Here, we highlight the importance of bioinformatic tool development to help facilitate a tools path to being used in the clinic. Copy number-based signatures have been shown to have potential in the discovery of new biomarkers, and here, we give an overview of our analysis package while comparing it to two other analysis pipelines recently published. We used this comparison to stress the importance of factors such as reliability, broad applicability, and ease-of-use when developing new bioinformatics tools. Overall, we focus on the importance of keeping cancer patients in mind during all stages of research, from molecular mechanisms to patient metal health.
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3رسالة جامعية
المؤلفون: Sotropa, Sarah
Committee Members: Guan, Jun-Lin
الملخص: p47 is a cofactor protein of p97/valosin-containing protein (VCP), an Adenosine Triphosphatase (ATPase) that plays a role in regulating various cellular processes, such as autophagy, Golgi assembly, and protein degradation. It is one of forty cofactors associated with p97/VCP, and its interaction with p97/VCP is particularly important for Golgi assembly during mitosis. Previous research has suggested that p47 interacts with p97/VCPthrough its SHP domain, leading to increased SNAP REceptor (SNARE)-SNARE interactions between Golgi membranes. In a recent Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) knock-out (KO) screen conducted by Dr. Hao to identify metastatic tumor suppressor genes in human epidermal growth factor receptor 2 (HER2)+ breast cancer cells, p47 emerged as a top candidate. To delve deeper into the role of p47 in HER2+ breast cancer metastasis, this thesis aimed to explore its background and its impact on Golgi morphology (therefore potentially its functions) in HER2+ breast cancer cells.This research used two HER2+ cell lines, murine N418 and human HCC-1954 cells, and discovered that the presence or absence of p47 resulted in significant alterations in Golgi morphology in these cells. In the presence of p47, both cell lines exhibited a compact Golgi trans-face, specifically in non-dividing cells. Conversely, in the absence of p47, both cell lines displayed more puncta structures and increased spreading of the Golgi. Thesefindings were consistent with previous studies conducted on tumor protein p53 gene (p53) mutant MDA-MB-231 non-dividing cells. Mutations in p53, a tumor suppressor protein like p47, have been shown to cause greater Golgi fragmentation compared to cells with normal p53 levels. Overall, this thesis provides strong evidence for the critical role of p47 in maintaining Golgi morphology in HER2+ breast cancer cells. These findings have potential implications for understanding the mechanisms involved in breast cancer metastasis and identifying targets for therapeutic intervention. Additionally, the findings highlights the importance of Golgi morphology as a potential biomarker for cancer diagnosis and prognosis in the future.
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4رسالة جامعية
المؤلفون: Kalogeros, James
Committee Members: Angela Alexander-Bryant, Ph.D; Brian Booth, Ph.D; Dan Simionescu, Ph.D
الملخص: More than 300,000 women will be diagnosed with breast cancer, and approximately 48,000 women will die this year due to the disease in the United States. HER2+ breast cancer accounts for 20-25% of invasive breast cancer, and it has a worse prognosis and higher early-stage mortality rate than other breast cancer subtypes. Common treatments for HER2+ breast cancer involve surgical removal of the breast or systemic therapy with chemotherapeutic drugs, both of which cause damage to healthy tissue. Due to the lack of a natural ligand for the HER2 receptor, there is a need for improved targeting strategies for the treatment of HER2+ breast cancer. Short interfering RNA, a type of RNA interference, is a promising tool for cancer treatment that works by silencing oncogenes on the mRNA level to reduce the expression of proteins contributing to cancer progression. siRNA requires a carrier to protect it from degradation and to mediate its delivery into a target cell. There are multiple types of carriers for siRNA delivery, including viral vectors and non-viral vectors such as polymeric nanoparticles, liposomes, and peptide-based nanoparticles. Peptides have advantages over other delivery mechanisms, such as control over functionalization, easier synthesis, and better biocompatibility. CD44, an oncogene correlated with HER2+ breast cancer, is directly involved in tumor growth and metastasis. CD44 is expressed in most healthy cells; therefore, silencing must be selective for HER2+ breast cancer. In this study, we investigated a novel strategy for treating HER2+ breast cancer utilizing peptide-mediated delivery of CD44-specific siRNA. We characterized two tandem peptides consisting of HER2 targeting peptides, P25 or P51, and the fusogenic peptide, DIV3W. By linking these two functional peptides, we aim to show that our tandem peptides can target the HER2 receptor and successfully deliver siCD44 to initiate the silencing of CD44 on the gene and protein level in HER2+ breast cancer cells. Characterization assays were performed to determine which tandem peptide possessed more optimal qualities as a carrier for siRNA. We observed that the tandem peptide, P25-DIV3W, protects siRNA from degradation, is cytocompatible, and promotes efficient internalization into HER2+ cell lines. P51-DIV3W showed poor siRNA protection and cytotoxic traits when delivered to HER2+ and HER2-normal cell lines. We then showed that P25-DIV3W loaded with siCD44 initiates the knockdown of CD44 and promotes cell death in HER2+ cell lines while not affecting the viability of normal breast epithelial cells in low concentrations.
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5رسالة جامعية
المؤلفون: Kyoreva, Mariela
Committee Members: Kennedy, Richard; Savage, Kienan
الملخص: HER2-amplified tumours are associated with poor prognosis, higher metastatic rate and shortened overall survival. Despite improvement in clinical activity, many patients still develop resistance to anti-HER2 targeting agents. This highlights the need for better understanding of HER2-driven biology to aid patient stratification and new therapeutic strategies. This study identifies HER2-binding partners in an ER-positive background, as well as their role in mediating pathway activation and response to therapy. HER2 phosphorylation status was also assessed regarding activation of downstream signalling cascades and receptor interactions. To investigate the role of HER2 phosphorylation sites (Y1248 and Y1221/22) in ER-positive HER2-positive background, two HER2-overexpressing model systems were generated: doxycycline inducible expression and stable expression systems. The HER2-negative MCF7 cell line was transduced with lentiviral vectors containing HER2-wild type (HER2-WT), HER2 single phospho-site mutants (HER2-Y1248F or HER2-Y1221/22F) or a HER2-double mutant (HER2-DM). The HER2 phospho-site mutants did not have an effect on proliferation, suggesting a potential redundancy in this pathway. HER2-Y1221/22F overexpressing MCF7 cells displayed reduced migratory ability compared to HER2-WT cells, which was coupled with reduced signalling through the ERK/MAPK pathway. In addition, the three phospho-site mutant HER2-overexpressing MCF7 cells demonstrated reduced anchorage-independent colony formation ability. RET was identified as a binding partner for HER2 through mass spectrometry analysis. Inhibition of HER2 tyrosine kinase activity using lapatinib resulted in decreased levels of both phospho-HER2 and phospho-RET, indicating that HER2 is required for RET activation. To elucidate the role of RET in downstream pathway activation, RET knockdown showed reduced phospho-ERK levels in HER2-positive cells. Phospho-RET expression levels were decreased in HER2-Y1248F mutant cells, suggesting that HER2 auto-phosphorylation is required for efficient RET activation. This implicates RET as an important mediator of MAPK activation in ER+HER2+ setting and highlights its importance as a drug target. To investigate the role of HER2 phosphorylation sites (Y1248 and Y1221/22) in ER-positive HER2-positive background, two HER2-overexpressing model systems were generated: doxycycline inducible expression and stable expression systems. The HER2-negative MCF7 cell line was transduced with lentiviral vectors containing HER2-wild type (HER2-WT), HER2 single phospho-site mutants (HER2-Y1248F or HER2-Y1221/22F) or a HER2-double mutant (HER2-DM). The HER2 phospho-site mutants did not have an effect on proliferation, suggesting a potential redundancy in this pathway. HER2-Y1221/22F overexpressing MCF7 cells displayed reduced migratory ability compared to HER2-WT cells, which was coupled with reduced signalling through the ERK/MAPK pathway. In addition, the three phospho-site mutant HER2-overexpressing MCF7 cells demonstrated reduced anchorage-independent colony formation ability. RET was identified as a binding partner for HER2 through mass spectrometry analysis. Inhibition of HER2 tyrosine kinase activity using lapatinib resulted in decreased levels of both phospho-HER2 and phospho-RET, indicating that HER2 is required for RET activation. To elucidate the role of RET in downstream pathway activation, RET knockdown showed reduced phospho-ERK levels in HER2-positive cells. Phospho-RET expression levels were decreased in HER2-Y1248F mutant cells, suggesting that HER2 auto-phosphorylation is required for efficient RET activation. This implicates RET as an important mediator of MAPK activation in ER+HER2+ setting and highlights its importance as a drug target. Finally, a 63-gene expression signature which detects HER2 phosphorylation at Y1248 was assessed in two breast cancer clinical cohorts. The phospho-HER2 signature had better prognostic value for predicting recurrence-free and overall survival than standard clinical HER2 testing. Moreover, the phospho-HER2 signature identified a poor prognosis subgroup within HER2-positive breast cancer patients, treated with either trastuzumab or endocrine therapy. The signature was applied across a panel of breast cancer cell lines and demonstrated a correlation with phospho-HER2 expression levels determined by western blot. Moreover, the phospho-HER2 signature showed an inverse correlation with response to lapatinib.
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6رسالة جامعية
المؤلفون: Alanazi, Samar
Committee Members: Garrett, Joan
الملخص: HER2 is over-expressed in around 15% to 20% of breast cancers. HER3 plays a critical role in HER2 mediated tumorigenesis. Increased HER3 transcription and protein levels occur upon inhibition of HER2. We aimed to identify proteins that bound to HER3 upon inhibition of the HER family with the pan-HER inhibitor neratinib in HER2+ breast cancer cells. Immunoprecipitation of HER3 followed by mass spectrometry experiments found non-muscle myosin IIA (NMIIA) increased upon neratinib treatment relative to vehicle DMSO treatment. MYH9 is the gene that encodes for the heavy chain of NMIIA. Breast cancer patients with high MYH9 were significantly associated with a shorter disease specific survival compared to patients with low MYH9 expression from the METABRIC cohort of patients. In addition, high MYH9 expression was associated with HER2+ tumors from this cohort. RT-qPCR and immunoblots of whole cell lysates of BT474 and MDA-MB-453 HER2+ breast cancer cells demonstrated elevated HER3 and NMIIA mRNA and protein levels upon neratinib treatment for 24 hours. To examine the role of NMIIA in HER2+ breast cancer, we modulated NMIIA levels in BT474 and MDA-MB-453 cells using doxycycline inducible shRNA targeting MYH9. MYH9 knockdown reduces HER3 protein levels and concomitant reduction in downstream P-Akt. In addition, loss of MYH9 suppresses cell growth, proliferation, migration, and invasion. Our data reveals that NMIIA regulates HER3 and loss of NMIIA reduces HER2+ breast cancer growth.
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7رسالة جامعية
المؤلفون: Purazo, Marc Louis
Committee Members: Emidio Pistilli; Paul Lockman
الملخص: Tumor initiation is often driven by unrestricted proliferation. One such driver of proliferation is Human epidermal growth factor receptor 2 (HER2). HER2 is a receptor tyrosine kinase that is part of the epidermal growth factor receptor family (EFGR) that is commonly overexpressed in breast cancer. HER2 positive (+) breast cancers often respond to anti- HER2 therapy, yet many patients eventually develop resistance. Multiple mechanisms contribute to resistance, including activation of HSP90, PI3K/Akt or Src that rely on adaptor molecules (GRB2, p130cas, NEDD9). Neural precursor cell expressed, developmentally downregulated protein 9 (NEDD9) is an adaptor protein that promotes integrin signaling. We found that higher expression of NEDD9 in HER2+ human breast cancer correlates with disease progression, reduced relapse free survival and resistance to anti-HER2 therapy. The central hypothesis is NEDD9 can play a role in mammary gland development, differentiation and proliferation of cells, and response to targeted therapy in HER2 driven breast cancer. To evaluate role of NEDD9 protein in physiologically relevant settings we generated a conditional transgenic mouse model, placing extra copy of human NEDD9 cDNA under the control of cre recombinase. When crossed with mice expressing mammary gland-specific cre recombinase, NEDD9 overexpression promoted early occurrence of benign lesions such as mammary intraepithelial neoplasia (MIN) and ductal carcinoma in situ (DCIS). This phenotype was accelerated by co-expression of HER2 oncogene. The NEDD9 overexpressing mice showed altered development of the mammary gland, with more tertiary and terminal end buds (TEBs), that is indicative of NEDD9’s role in controlling proliferation. The increase in cell proliferation, was further supported by Ki67 staining. The lineage tracing analysis shows that NEDD9 specifically increased the number of luminal progenitor cells, as shown by dual Keratin 5/8 staining. Consistent with these studies, NEDD9 promoted the 2D and 3D cell proliferation of human MCF10A cells. Mechanistically, NEDD9 upregulation resulted in MAPK and AURKA activation inducing cell proliferation. The depletion of NEDD9 in HER2+ cancer cell lines increased their sensitivity to anti-HER2 therapy. These findings support the role of NEDD9 in early stages of HER2-driven tumorigenesis, selectively impacting proliferation of luminal progenitor cells and lay foundation for potential use of NEDD9 expression in early diagnostics of HER2+ BCs and treatment.
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8رسالة جامعية
المؤلفون: Zhang, Jingwei
Committee Members: Tournier, Cathy; Finegan, Katherine
الملخص: In the first part of my phd work, I deciphered ERK5 as a new potential target to overcome resistance to anti-HER2 target therapy (small molecular kinase inhibitor and monoclonal antibody) in HER2+ breast cancer. More specifically, I found that ERK5 is constitutively activated in HER2+ breast cancer cells, and this constitutive activation can be inhibited by lapatinib in anti-Her2 sensitive cells but not in resistant cells. I also validated that ERK5 inhibitors (JWG-045 and AX15836) and MEK5 inhibitor (BIX02189) suppressed Rb phosphorylation in HER2+ breast cancer cells. As a result, inhibition of MEK5/ERK5 signalling enhanced anti-HER2 therapy in resistant breast cancer cell lines by causing G1 arrest. Additionally, I found that shERK5 enhanced the anti-lapatinib effect in Xenograft model. In the second part of my phd work, I found that ERK5 phosphorylation was transiently increased by irradiation in HER2+ breast cancer cells. Also, this transient activation of ERK5 was involved in IR-induced G2/M arrest in HER2+ breast cancer cells.
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9رسالة جامعية
المؤلفون: Walia, Yashna
Advisors: Furuta, Dr. Saori
Committee Members: Vestal, Dr. Deborah
الملخص: Among women in the US, breast cancer is the second leading cause of cancer related death, only preceded by lung cancer. This study primarily focuses on HER2, an oncogene involved in approximately 20% of all breast cancer cases. Our previous studies have found that there is a link between HER2 and nitric oxide (NO). This study aims to address the mechanistic bases of the link between HER2 and NO. Here, the primarily focus is on S nitrosylation, a post translational modification mediated by NO and its effect on the HER2 function. For this purpose, cysteine to alanine substitution were generated at predicted S nitrosylation sites of HER2 to determine their actual involvement in S nitrosylation. The results suggests that mutation at residues 7 and 600 impacts HER2 S nitrosylation, while also affecting HER2 expression (C7A) and activity (C7A and C600A). However, future experiments are essential to investigate whether S nitrosylation of HER2 is indeed involved in breast cancer initiation and progression. Such information could be utilized for the development of a therapeutic method that prevents S nitrosylation of HER2.
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10رسالة جامعية
المؤلفون: Diwanji, Devan
Committee Members: Weiss, William
الملخص: Cell communication is essential for cellular function and relies on the faithful transmission of signals across the plasma membrane through membrane receptors. Receptor kinases constitute an important class of molecular antennas in which the extracellular signal binding module is linked to an intracellular kinase along one polypeptide chain. Perturbations in this finely coordinated system causes aberrant signaling which lead to pathological states such as cancer or developmental disorders. Despite the disease relevance and extensive therapeutic focus, we fundamentally do not understand how receptor kinases transmit a signal across the plasma membrane in the absence of full-length structures. This is particularly true for the Human Epidermal Growth Factor Receptor 2 (HER2), an orphan receptor, and the Human Epidermal Growth Factor Receptor 3 (HER3), a pseudokinase receptor which form a potent pro-oncogenic heterocomplex upon binding to extracellular ligand. Here, we present three novel high-resolution cryo-electron microscopy (cryo-EM) structures of the extracellular domain of the breast cancer receptor, HER2, engaged with its liganded co-receptor, HER3, solved in the context of near full-length receptors. As the first singly-liganded human HER receptor structures, our findings provide a missing link in the HER receptor field, offer the dimerization arm as an allosteric sensor for ligand binding, visualize HER3 in an extended state for the first time, demonstrate how the most frequent oncogenic HER2 variant, HER2 S310F, exploits dimerization arm dynamics to enhance heterodimerization, and unveil previously unknown details on how commonly prescribed biologic agents bind the heterodimer. Our studies on near full-length HER2 and HER3, when isolated alone, surprisingly reveal that HER2 is a homodimer that may adopt an autoinhibited state and HER3, contrary to dogma, homodimerizes in the presence of NRG1b. Taken together, these findings made possible through the lens of full-length receptor biophysics, explain ligand allostery, inform rational drug design, and add nuance to a model of HER2/HER3/NRG1b heterocomplex assembly.
