Cancer Biology Commons^™

Functional Regulation Of Yap By Aurora A Kinase In Triple-Negative Breast Cancer, Shih-Shin Chang

Dissertations and Theses (Open Access)

The Yes-associated protein (YAP) is an effector that transduces the output of the Hippo pathway to transcriptional modulation. Considering the role of YAP in cancers, this protein has emerged as a key node in malignancy development. In this study, we determined that Aurora A kinase acts as a positive regulator for YAP-mediated transcriptional machinery. Specifically, YAP associates with Aurora A predominantly in the nucleus. Activation of Aurora A can impinge on YAP activity through direct phosphorylation. Moreover, aberrant expression of YAP and Aurora A signaling is highly correlated with triple-negative breast cancer (TNBC). We herein provide evidence to establish the …

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

Dissertations and 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 …

The Role Of Gdf15 In Ovarian Cancer, Daisy I. Izaguirre

Dissertations and Theses (Open Access)

Growth Differentiation Factor 15 (GDF15) is induced in situations such as stress, inflammation, treatment with non-steroidal anti-inflammatory drugs, as well as other therapeutic agents. As a secreted protein, GDF15 is seen as a potential biomarker in several types of cancer as well as in other diseases such as cardiovascular diseases, diabetes, and rheumatoid arthritis. In ovarian cancer, high GDF15 serum levels correspond to poor survival. It has further been shown to be expressed at higher levels in serum in ovarian cancer patients post-chemotherapy than pre-chemotherapy.

The overall 5-year survival for ovarian cancer is 46%, as a result of late diagnosis …

Gsk3Beta-Mediated Ezh2 Phosphorylation Suppresses Methylation Of H3k27 And Ezh2’S Oncogenic Functions, How-Wen Ko

Dissertations and Theses (Open Access)

During the process of tumorigenesis, inactivation of tumor suppressors is a critical step. Enhancer of zeste homolog 2 (EZH2), a histone methyltransferase and the enzymatic core subunit of polycomb repressive complex 2 (PRC2), promotes cell growth and migration through catalyzing trimethylation of histone H3 at Lys 27 (H3K27me3) and plays an important role in tumorigenesis. Its expression can be controlled by phosphorylation. However, the regulation of EZH2 activity by tumor suppressor kinase is not well understood. Glycogen synthase kinase 3 beta (GSK3b), a multifunctional serine/threonine kinase, is involved in many cellular processes. GSK3b also participates in neoplastic transformation, tumor development …

In Vivo Kinome Screen Reveals Non-Canonical Cdk-Driven Metabolic Adaptation In Brain Metastasis, Frank J. Lowery Iii

Dissertations and Theses (Open Access)

Brain metastasis, which frequently arises from breast cancer, lung cancer, melanoma, and colorectal cancer, remains a severely unmet medical need and its incidence continues to rise while treatment options remain palliative. To better understand the biology underlying its aggressive, incurable nature, I performed an unbiased in vivo kinome screen to identify potential driver kinases of experimental brain metastasis in a nude xenograft model using the human breast cancer cell line MDA-MB-231. Several of the kinase pools led to decreased brain metastasis-specific survival in nude mice, shortening survival time by up to 50% relative to controls. Targeted next-generation sequencing (NGS) was …

Identifying Protein Kinase Tbk1 As A Novel Inhibitor Of Intestinal Tumorigenesis, Amber L. Mathews

Dissertations and Theses (Open Access)

Colorectal cancer (CRC) is the third most common cancer diagnosed in women and men， causing almost 600,000 annual deaths worldwide. There is a clear need to understand how CRC forms and progresses in order to improve the strategies of CRC prevention and therapy. A major factor that drives the development of CRC is genetic mutations that lead to activation of oncogenes and inactivation of tumor suppressor genes in intestinal epithelial cells (IECs). In addition, the initiation and progression of CRC involve environmental and immunological factors. In particular, chronic inflammatory conditions are known as an important risk factor for CRC. Intestinal …

The Tumor Suppressor Notch Inhibits Head And Neck Squamous Cell Carcinoma (Hnscc) Tumor Growth And Progression By Modulating Proto-Oncogenes Axl And Ctnnal1 (Α-Catulin), Shhyam Moorthy, Shhyam Moorthy

Dissertations and Theses (Open Access)

Background: Head and Neck Squamous Cell Carcinoma (HNSCC) is the sixth most common malignancy worldwide, with roughly 300,000 cancer related deaths occurring globally each year. The survival of patients with HNSCC has not changed significantly over the past decade, leading investigators to search for promising molecular targets. To identify new treatment targets and biomarkers that could better guide therapy, we previously characterized the genomic alterations from primary HNSCC patient samples. We were among the first to discover that NOTCH1 is one of the most frequently mutated genes in this cancer type. The spectrum of inactivating NOTCH1 mutations in HNSCC suggested …

Normal Glycolytic Enzyme Activity Is Critical For Hypoxia Inducible Factor-1a Activity And Provides Novel Targets For Inhibiting Tumor Growth, Geoffrey Grandjean Phd

Dissertations and Theses (Open Access)

Normal Glycolytic Enzyme Activity is Critical for Hypoxia Inducible Factor-1α Activity and Provides Novel Targets for Inhibiting Tumor Growth

By Geoffrey Grandjean

Advisory Professor: Garth Powis, D. Phil

Unique to proliferating cancer cells is the observation that their increased need for energy is provided by a high rate of glycolysis followed by lactic acid fermentation in a process known as the Warburg Effect, a process many times less efficient than oxidative phosphorylation employed by normal cells to satisfy a similar energy demand ^[1]. This high rate of glycolysis occurs regardless of the concentration of oxygen in the cell and …

Investigating The Role Of Cholesterol Metabolism And Synthesis In Metastasis And Radiation Response In Aggressive Subtypes Of Breast Cancer, Adam Wolfe

Dissertations and Theses (Open Access)

Aggressive breast cancers, triple-negative breast cancer (TNBC) and inflammatory breast cancer (IBC), metastasize at a high rate and are notoriously resistant to standard treatments. Research has shown diets high in cholesterol increase the incidence of aggressive breast cancers and pre-clinical research has shown cholesterol can fuel the growth of breast cancer in vivo. Studies at MD Anderson have shown that IBC patients taking cholesterol lowering drugs, statins, have improved survival outcomes, and also statins can improve the response to radiation in vitro. Furthermore, statins have been shown to target the cells with stem like-properties called cancer stem cells (CSCs) which …

Direct Regulation Of Apoptosis By Linear Ubiqutin Chain Assembly Complex (Lubac) And Feedback Regulation Of Lubac Function By Caspases, Donghyun Joo

Dissertations and Theses (Open Access)

Tumor Necrosis Factor-alpha (TNF-α) is a cytokine that plays a role in various cellular processes such as proliferation, differentiation (mainly through NF-κB signaling) and death (via apoptosis signaling). Recently, linear ubiquitination by LUBAC (linear ubiquitin chain assembly complex) was reported to have a regulatory function in TNF-α mediated NF-κB activation. Although LUBAC is suggested to control not only NF-kB signaling but also the apoptosis pathway, the precise mechanism of apoptosis regulation remains unknown. Moreover, NF-κB and apoptosis pathways have opposed but fundamental functions for various cellular processes. Although these two pathways actively interplay to balance the death and survival, the …

Induction Of Caspase-Dependent Death By Proteasome Targeted Therapy In Glioblastoma, Christa A. Manton

Dissertations and Theses (Open Access)

New therapeutic options are needed for glioblastoma, a deadly disease with a median survival of only 14 months with current treatment. The proteasome inhibitor bortezomib (BTZ) shows efficacy in cancers like myeloma, but its clinical utility in other cancer types has been more limited. Newer proteasome inhibitors such as marizomib (MRZ) have unique inhibitory and death inducing properties that have not been well examined in GBM. Additionally, targeting other components of the ubiquitin-proteasome system is possible, but has not been explored in GBM. Questions also still remain about the ability of BTZ and MRZ to be delivered to brain tumors …

Igfbp2 Potentiates Egfr-Stat3 Signaling In Glioma, Yingxuan Chua

Dissertations and Theses (Open Access)

Gliomas are clinically challenging brain tumors with dismal survival rates due to its infiltrative nature and ineffective standard therapy. Insulin-like growth factor binding protein 2 (IGFBP2) is a pleiotropic oncogenic protein that has both extracellular and intracellular functions. Despite a clear causal role in cancer development, the contributions of intracellular IGFBP2 to tumor development and progression are poorly understood. Here we present evidence that both exogenous IGFBP2 treatment and cellular IGFBP2 overexpression lead to aberrant activation of EGFR, which subsequently activates STAT3 signaling. Furthermore, we demonstrate that IGFBP2 augments the nuclear accumulation of EGFR to potentiate STAT3 transactivation activities, via …

Dna Polymerase Θ (Polq) And The Cellular Defense Against Dna Damage, Matthew J. Yousefzadeh

Dissertations and Theses (Open Access)

In mammalian cells, DNA polymerase θ (POLQ) is an unusual specialized DNA polymerase whose in vivo function is under active investigation. The protein is comprised of an N-terminal helicase-like domain, a C-terminal DNA polymerase domain, and a large central domain that spans between the two. This arrangement is also found in the Drosophila Mus308 protein, which helps confer resistance to DNA interstrand crosslinking agents. Homologs of POLQ and Mus308 are found in eukaryotes, including plants, but a comparison of phenotypes suggests that not all of these genes are functional orthologs. Flies with defective Mus308 are sensitive to DNA interstrand crosslinking …

Cancer Associated Fibroblast Derived Angiogenic Factor Mfap5 In Ovarian Cancer Progression, Sze Lee Cecilia Leung

Dissertations and Theses (Open Access)

Advanced stage ovarian cancer is the most lethal gynecologic malignancy. No major improvement on patient survival has been achieved in the past decade. Therefore, identification of predictive or prognostic markers and further understanding of the molecular mechanisms in ovarian cancer progression are of paramount importance.

While cancer cells have always been the targets for the identification of prognostic and predictive markers, the potential for developing new diagnosis and treatments based on the tumor supporting stromal microenvironment is relatively unexplored. Using transcriptome profiling analysis on microdissected stromal and epithelial components of normal and malignant ovarian tissues, we identified a gene signature …

Microrna-200 Regulates Ecm-Dependent Β1-Integrin/Fak Signaling And Cancer Cell Invasion, Christin Ungewiss

Dissertations and Theses (Open Access)

The microRNA-200 family is known to be a master regulator of the epithelial-to-mesenchymal transition, partially through its double-negative feedback loop with the transcriptional repressor Zeb1, yet the mechanisms on how miR-200 controls the invasive phenotype are not fully understood. Recent studies have shown that the miR-200/Zeb1 axis regulates cell-cell and cell-matrix interactions, but it has also been demonstrated that cell-intrinsic changes are insufficient to drive cancer cell invasion, leading us to focus on specific cell-matrix interactions required to activate tumor cell invasion and metastases. We have shown through 3D studies that the Integrin β1-collagen I contact is critical in mediating …

Atp-Citrate Lyase Links Cyclin E To Cellular Metabolism In Breast Cancer, Kim Lucenay

Dissertations and Theses (Open Access)

Cyclin E is altered or overexpressed in approximately one-third of tumors from patients with invasive breast cancer and is a powerful independent predictor for survival in women with stage I-III breast cancer. Full-length cyclin E (EL) is post-translationally cleaved into two low-molecular-weight isoforms, LMW-E (T1) and LMW-E (T2). LMW-E have been shown to exhibit greater binding affinity for cyclin-dependent kinase 2 (CDK2) , cyclin dependent kinase inhibitors (CKIs), p21 and p27, but are resistant to p21 and p27 inhibition. In addition, transgenic mice expressing LMW-E have increased mammary tumor development and metastasis compared to EL transgenic mice. Therefore, LMW-E are …

Understanding The Role Of Sumoylation In Regulating Lkb1 Function, Joan W. Ritho

Dissertations and Theses (Open Access)

Energy homeostasis in a cell is critical for its survival during metabolic stress. Liver kinase B1 (LKB1), one of the key regulators of cellular energy balance, was initially discovered as a tumor suppressor mutated in patients with Peutz-Jeghers syndrome. Germline mutations in LKB1 predispose patients to develop several benign and malignant tumors including gastrointestinal and lung cancers. In 2003, several groups demonstrated that LKB1is a major upstream kinase of the energy sensor AMP-activated protein kinase (AMPK), directly associating it with the regulation of energy balance in cells. During energy stress, LKB1 phosphorylates AMPK at threonine 172 (T172) resulting in AMPK …

The Role Of Autophagy In The Sensitivity Of Osteosarcoma Cells To Gemcitabine Treatment, Janice M. Santiago-O'Farrill

Dissertations and Theses (Open Access)

Despite treatment improvement for osteosarcoma (OS), overall survival has remained unchanged in the last 20 years. Pulmonary metastasis continues to be the main cause of death; novel therapeutic strategies are urgently needed to improve the survival rate of these patients. Previous data in our laboratory has demonstrated that aerosol gemcitabine (GCB) treatment has a significant therapeutic effect on metastatic OS. However, treatment efficacy is decreased due to acquired resistance by a population of tumor cells that fails to respond to treatment. Recent studies have implicated autophagy as a resistance mechanism in various types of cancer. The purpose of this study …

Actions Of Pi3k-Delta Inhibitor, Idelalisib, And Its Combination With Bendamustine In Chronic Lymphocytic Leukemia, Prexy Modi

Dissertations and Theses (Open Access)

Class I phosphatidylinositol 3-kinase isoforms (α, β, δ, and γ) play a major role in cancer cell growth and survival. PI3K α and β are most studied. PI3K pathway is highly dysregulated in many cancers and aberrant PI3K signaling is associated with oncogene mutations and disease progression in solid tumors and in hematologic malignancies.

Chronic lymphocytic leukemia (CLL) is driven by B-cell receptor (BCR) signaling that promotes B-cell proliferation and survival. PI3K is a critical node in BCR pathway and PI3Kδ has a pivotal role in B-cell development and maintenance and this isoform is over-expressed in many B-cell malignancies, including …

Investigating The Roles Of P63 And P73 Isoforms To Therapeutically Treat P53-Altered Cancers, Avinashnarayan Venkatanarayan

Dissertations and Theses (Open Access)

Investigating the roles of p63 & p73 isoforms to therapeutically treat

p53-altered cancers

Avinashnarayan Venkatanarayan, M.S.

Supervisory Professor: Elsa R. Flores, Ph.D.

The TP53 tumor suppressor is mutated in approximately 50% of human cancers rendering cancer therapies ineffective. p53 reactivation suppresses tumor formation in mice. However, this strategy has proven difficult to implement therapeutically. An alternate approach to overcome p53 loss is to manipulate the p53-family members, p63 and p73, which interact and share structural similarities to p53. p63 and p73, unlike p53 are less frequently mutated and have two major isoforms with distinct functions …

Impact Of Differentiation Status Of Kidney Progenitors In Wilms Tumor Development, Le Huang

Dissertations and Theses (Open Access)

Wilms tumor is one of the most common solid tumors in children. It is an embryonic cancer of the kidney and is thought to arise from undifferentiated renal mesenchyme. However, the differentiation status of cells in the mesenchyme that can give rise to Wilms tumors is unknown. Gene expression analysis of a large panel of Wilms tumor patients has identified different subsets of Wilms tumors that are distinct in their clinical outcomes and gene expression signatures. These subsets express specific genes that correspond to different stages of differentiation during renal development, suggesting that Wilms tumors may arise from transformed cells …

Measuring Single Cell Responses To Lapatinib In A Heterogeneous Population, Preety Priya

Dissertations and Theses (Open Access)

Cancer is notonedisease butasaga of diseases and is the outcome of disturbed homeostasis in the normal cells due to the deregulation of its genetic makeup. With advent of technologies thatallowdetailed molecular characterizationoftumors, targeted therapies have emerged as a more promising and specific mode of treatment. However, a major challenge with targeted therapy is the acquired resistance in the cancer cells to these therapies, quite often very rapidly in the course of a few months. One of the major targets in cancer has been the EGFR/ErbB2 network in breast and other cancer types. Prior work from our lab and others have …

Regulation Of Cell Adhesion By The Ferm Proteins, Ptpn14 And Merlin, Patty Dimarco Hewitt

Dissertations and Theses (Open Access)

Cell-cell adhesion is critical for the control of tissue organization and homeostasis. A family of proteins that regulate cell-cell adhesions is the FERM (4.1 protein, Ezrin, Radixin, Moesin) domain-containing proteins.One FERM domain protein, the non-receptor tyrosine phosphatase PTPN14, is mutated or deleted in several human cancers suggesting that it may be involved in tumor development and/or progression. Additionally, the loss of the FERM domain protein Merlin is associated with tumor development and metastasis.Both PTPN14 and Merlin have been shown to localize and possibly regulate adherens junction (AJ) functions. This work sought to determine if …

Novel Posttranslational Modification In Lkb1 Activation And Function, Szu-Wei Lee

Dissertations and Theses (Open Access)

Cancer cells display dramatic alterations in cellular metabolism to meet their needs of increased growth and proliferation. In the last decade, cancer research has brought these pathways into focus, and one emerging issue that has come to attention is that many oncogenes and tumor-suppressors are intimately linked to metabolic regulation (Jones and Thompson, 2009). One of the key tumor-suppressors involved in metabolism is Liver Kinase B1 (LKB1). LKB1 is the major upstream kinase of the evolutionarily conserved metabolic sensor—AMP-activated protein kinase (AMPK). Activation of the LKB1/AMPK pathway provides a survival advantage for cells under energy stress. LKB1 forms a heterotrimeric …

Lkb1 Deficient Non-Small Cell Lung Cancer Cells Are Vulnerable To Energy Stress Induced By Atp Depletion, Chao Yang

Dissertations and Theses (Open Access)

Lung cancer is the second most frequent cancer in United States, which represents about 13.5% of new cancer cases every year. It accounts for about 27.2% of all cancer related deaths, which is more than the sum of deaths caused by prancretic, breast and colorectal. On average, only about 16% of lung cancer patients survive beyond 5 years. LKB1 is the third most mutated gene in lung cancer. It has been shown that LKB1 is mutated in at least 15% to 30% of NSCLC. Tumor with LKB1 mutation is associated with poor differentiation, high metastasis and worse response to chemotherapy. …

Role Of Phosphorylation Of Focal Adhesion Kinase At Tyrosine 861 In Prostate Cancer Metastasis, Tanushree Chatterji

Dissertations and Theses (Open Access)

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that mediates interactions between the extracellular matrix and intracellular signaling pathways critical in promoting numerous cellular functions including adhesion, proliferation, survival and migration. Most FAK functions result from phosphorylation by Src family kinases, which trigger numerous signaling cascades. Overexpression of FAK is associated with metastasis in many solid tumors, including prostate cancer. Hence, understanding the mechanisms by which FAK is regulated in prostate cancer will better elucidate its role in prostate cancer metastasis. Work in this dissertation tested the hypothesis that altered phosphorylation of FAK is critical for cell migration and …

Sustained Adrenergic Signaling Promotes Cervical Cancer Progression, Nouara C. Sadaoui

Dissertations and Theses (Open Access)

Background: Chronic stress and sustained adrenergic signaling are known to promote tumor progression. The underlying mechanisms behind this process are not well understood. We examined the effects of sustained adrenergic signaling on cervical cancer progression through increased expression of HPV oncogenes, E6 and E7.

Materials and Methods: ADRβ expression levels were examined in patient-derived cervical cancer samples. We used an orthotopic model of cervical cancer to investigate the effects of restraint stress on tumor growth and metastasis. We evaluated the in vivo effects of a β-blocker, propranolol, and HPV E6/E7 siRNA. In vitro, ADRβ positive cervical cancer cells were …

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

Dissertations and 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 …

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

Dissertations and 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 …

Epidermal Growth Factor Receptor Induces Fyn Expression Via Up-Regulation Of P47phox In Glioblastoma Multiforme, Blake P. Johnson

Dissertations and Theses (Open Access)

Src family kinases (SFKs) are commonly over-expressed and/or activated in glioblastoma multiforme (GBM), where they serve as key mediators of GBM cell proliferation, survival, invasion and angiogenesis. Mechanisms of allosteric SFK activation are well described; however, the SFK Fyn is commonly up-regulated at the mRNA level in multiple human cancers, including GBM, where the mode of increased expression is poorly understood. Since activating mutations in the epidermal growth factor receptor (EGFR) are commonly occurring in GBM, we examined whether EGFR could induce Fyn expression. Here, we found that wild-type EGFR, and to a greater extent hyper-activating EGFR mutants, EGFRΔIII and …