Cancer Biology Commons^™

Novel Mechanisms Of Protein Kinase C Α Regulation And Function, Xinyue Li

Theses & Dissertations

Protein kinase Cα (PKCα) is a member of the PKC family of serine/threonine kinases, which have been implicated in regulation of many cellular processes, including cell proliferation, differentiation, survival, and transformation. A large body of evidence from the Black laboratory and others support an anti-proliferative function of PKCα in normal epithelial tissues, including the intestinal mucosa and endometrial epithelium. PKCα is also tumor suppressive in epithelial cancers, such as colorectal cancer (CRC) and endometrial cancer (EC). However, a major obstacle to harnessing the tumor suppressive functions of PKCα to benefit patients is the widespread loss of PKCα expression in tumors. …

Post-Transcriptional Control Of The Epithelial-To-Mesenchymal Transition (Emt) In Ras-Driven Colorectal Cancers, Chaitra Rao

Theses & Dissertations

Colorectal cancer (CRC) originates from epithelial cells lining the colon or rectum of the gastrointestinal tract. Most cancer deaths result from a tumor spreading to distant organs; however epithelial cells do not normally migrate from their tissue of origin. To do so, epithelial cells undergo biochemical changes allowing them to acquire behavior similar to motile mesenchymal cells termed the epithelial-to-mesenchymal transition (EMT), which contributes to tumor invasion and metastasis. Our study demonstrated that CRC cells require a molecular scaffold, Kinase Suppressor of Ras 1 (KSR1), and ERK to promote the EMT-like phenotype through the preferential translation of Epithelial Stromal Interaction …

Sox2 Dosage Governs Tumor Cell Identity And Proliferation, Ethan P. Metz

Theses & Dissertations

The stem cell transcription factor SOX2 has been widely recognized for its critical roles during mammalian development. SOX2 expression has also been implicated in more than 20 types of human cancers. Importantly, the expression of SOX2 is regulated at multiple levels, which enables the tight regulation of SOX2 levels. Previous work from our laboratory has shown that elevating SOX2 from an inducible promoter inhibits the proliferation of several human tumor cell types. Other studies have reported that high levels of SOX2 are necessary to maintain lineage plasticity in advanced tumors. Thus, the dosage of SOX2 plays a critical role in …

Characterization Of 1,1-Diarylethylene Foxm1 Inhibitors Against High-Grade Serous Ovarian Carcinoma Cells, Cassie Liu

Theses & Dissertations

Forkhead box M1 (FOXM1) is a member of the conserved forkhead box (FOX) transcription factor family. Over the last two decades, FOXM1 has emerged as a multifunctional oncoprotein and a robust biomarker of poor prognosis in many human malignancies. FOXM1 and its associated oncogenic transcriptional signature are enriched in >85% of ovarian cancer cases, and FOXM1 expression and activity can be enhanced by a plethora of genomic, transcriptional, post-transcriptional, and post-translational mechanisms. As a master transcriptional regulator, FOXM1 promotes critical oncogenic phenotypes in ovarian cancer, including: (1) cell proliferation, (2) invasion and metastasis, (3) chemotherapy resistance, (4) cancer stem cell …

A Pkcα-Mediated Growth Suppressive Mek-Erk Signaling Axis In Intestinal Epithelial Cells, Navneet Kaur

Theses & Dissertations

Members of the protein kinase C (PKC) family of serine/threonine kinases are involved in regulation of fundamental cellular functions, including proliferation, differentiation, survival, migration, and transformation. Increasing evidence points to anti-proliferative and tumor suppressive role of PKCs. Our laboratory and others have reported that the classical PKC isozyme, PKCαnegatively regulates proliferation and tumorigenesis in the intestinal epithelium. Our laboratory has further determined that PKCα signaling induces a program of cell cycle withdrawal in intestinal epithelial cells that involves downregulation of the pro-proliferative proteins, cyclin D1 and Id1, and upregulation of the cyclin dependent kinase (CDK) inhibitor, p21^Cip1. Unexpectedly, …

Molecular Mechanisms Of Aberrant Protein Glycosylation In Pancreatic Cancer Stemness And Metastasis, Frank Leon

Theses & Dissertations

A myriad of genetic and other abnormal changes underlies the aggressiveness and dissemination properties observed in pancreatic cancer (PC). Aberrant protein glycosylation is a commonly observed feature in PC. The modification of protein O-glycosylation is mediated by glycosyltransferases, which attach and sequentially elongate monosaccharides on Serine/Threonine (Ser/Thr) motifs. Aberrant glycosylation is recognized as an emerging hallmark of cancer where a disruption in normal glycosylation results in irregular O-glycans.

This dissertation research has investigated the consequences of aberrant protein glycosylation on stemness and enhancement of metastatic properties in pancreatic ductal adenocarcinoma (PDAC). Several publications have reported aberrant O-glycosylation increases in oncogenic …

Role Of Endocytic Machinery Regulators In Egfr Traffic And Viral Entry, Insha Mushtaq

Theses & Dissertations

STUDY 1: Role of endocytic regulator EHD1 and its binding partner RUSC2 in EGFR traffic

Abstract

Epidermal growth factor receptor (EGFR) is a prototype receptor tyrosine kinase and an oncoprotein in many solid tumors. Cell surface display of EGFR is essential for cellular responses to its ligands. While post activation endocytic trafficking of EGFR has been well elucidated, little is known about mechanisms of basal/pre-activation surface display of EGFR. Here, we identify a novel role of the endocytic regulator EHD1 and a potential EHD1 partner, RUSC2, in cell surface display of EGFR. EHD1 and RUSC2 colocalize with EGFR in vesicular/tubular …

Mechanisms By Which Mnte-2-Pyp Suppresses Prostate Cancer Cell Growth, Yuxiang Zhu

Theses & Dissertations

Prostate cancer patients are often treated with radiotherapy. MnTE-2-PyP, is a superoxide dismutase (SOD) mimic and a known radioprotector of normal tissues. Our recent work demonstrates that MnTE-2-PyP also inhibits prostate cancer progression with radiotherapy; however, the mechanisms remain unclear. In this thesis, we identified that MnTE-2-PyP-induced intracellular H2O2 levels are critical in inhibiting growth of prostate cancer cells. We found that MnTE-2-PyP induced protein oxidations in PC3 cells and one major group of oxidized protein targets were involved in energy metabolism. The oxidative phosphorylation rates were significantly enhanced in both PC3 and LNCaP cells with MnTE-2-PyP treatment, but mitochondrial …

The Cellular Origin And Molecular Drivers Of Claudin-Low Mammary Cancer, Patrick D. Raedler

Theses & Dissertations

Breast cancers of the claudin-low subtype make up a substantial portion of triple-negative breast cancers and have stem cell-like and mesenchymal features. Although it has been recognized for some time that this breast cancer subtype is highly aggressive and difficult to treat, the molecular drivers and cellular origin of claudin-low breast cancer have been poorly defined. The lack of suitable in vivo models has prohibited the study of tumor initiation and progression of this subtype. In this work, we report two novel mouse models that, upon expression of oncogenic RAS in the mammary epithelium, develop highly metastatic triple-negative mammary tumors …

Mechanism Of Bax/Bak Activation In Apoptotic Signaling, Kai Huang

Theses & Dissertations

The Bcl-2 family proteins, including the anti-apoptotic members, pro-apoptotic effectors Bax/Bak, and the BH3-only proteins, are key components of the mitochondrial apoptotic pathway. The BH3-only protein Bid is critical for the mitochondrial pathway of apoptosis after TRAIL-induced death receptor activation. However, the mechanism of Bid activation during TRAIL-induced apoptosis is unclear. By putting back wild-type and mutants of Bid in Bid deficient (Bid KO) and Bid/Bax/Bak TKO colon cancer cells, we demonstrated that cleavage by caspase 8 and mitochondrial targeting are critical events for Bid activation. One of the biggest mysteries in apoptosis is how Bax/Bak was activated by BH3-only …

Brca1 & Ctdp1 Brct Domainomics In The Dna Damage Response, Kimiko L. Krieger

Theses & Dissertations

Genomic instability is one of the enabling characteristics of cancer. DNA damage response pathways are important for genomic integrity and cell cycle progression. Defects in DNA damage repair can often lead to cell cycle arrest, cell death, or tumorigenesis. The activation of the DNA damage response includes tightly regulated signaling cascades that involve kinase phosphorylation and modular domains that scaffold phosphorylated motifs to coordinate recruitment of DNA repair proteins. Modular domains are conserved tertiary structures of a protein that can fold, function, and evolve independently from an intact protein. One of the most common modular domains involved in DNA damage …

Developing Targeted Therapy Against Pancreatic Cancer, Garima Kaushik

Theses & Dissertations

Not available.

Identification Of Pathways Required For The Survival Of Inversion(16) Acute Myeloid Leukemia, Yiqian Wang

Theses & Dissertations

Inversion of chromosome 16 [inv(16)] acute myeloid leukemia (AML) generates a fusion gene CBFB-MYH11. Approximately half of inv(16) AML patients eventually relapse mainly due to the existence of leukemia stem cells (LSCs). Previous work using a Cbfb-MYH11 knockin mouse model showed that the LSCs are enriched within CSF2RB^- population. Another gene upregulated by Cbfb-MYH11 encodes the cytokine receptor IL1RL1. Using Cbfb-MYH11 knockin mice, we showed that LSCs exist in multiple sub-populations defined by their immunophenotype, and IL1RL1 is expressed by cell populations with high LSC activity. We also found that treatment of IL-33, the ligand for IL1RL1, promoted …

The Role Of Zyxin And Limd1 In Mitosis And Cancer, Jiuli Zhou

Theses & Dissertations

The Hippo signaling pathway, originally discovered in Drosophila, consists of a core kinase cascade and has been subsequently demonstrated to control tissue growth and tumorigenesis. The core of this pathway contains MST1/2 (Mammalian sterile 20-like kinase 1/2), LATS1/2 (large tumor suppressor 1/2) and downstream effector named Yes-associated protein (YAP) and PDZ-binding motif (TAZ). MST1/2 transduce their kinase activity mainly through directly phosphorylating LATS1/2. Once phosphorylated and activated, LATS1/2 subsequently phosphorylate and inhibit YAP/TAZ from translocating to nucleus, thereby suppressing the expression of downstream pro-growth and survival genes. While recent studies provide important insight into the tumor suppressor properties of …

Regulation Of Canonical And Non-Canonical Hippo Pathway Components In Mitosis And Cancer, Seth Stauffer

Theses & Dissertations

The Hippo pathway is conserved regulator of organ size through control of proliferation, apoptosis, and stem-cell self-renewal. In addition to this important function, many of the canonical signaling members have also been shown to be regulated during mitosis. Importantly, Hippo pathway components are frequently dysregulated in cancers and have attracted attention as possible targets for improved cancer therapeutics. Further exploration of Hippo-YAP (yes-associated protein) signaling has revealed new regulators and effectors outside the canonical signaling network and has revealed a larger non-canonical network of signaling proteins in which canonical Hippo pathway components crosstalk with important cellular homeostasis and apoptosis signaling …

Delineation Of New Mechanisms Of Dna Double Strand Break Repair, Songli Zhu

Theses & Dissertations

DNA damage is frequently induced in cells by both endogenous and exogenous agents. DNA damage, particular double strand breaks (DSBs) may lead to genomic instability, and the progression of cancer, aging, neurodegeneration, and other human diseases. The cell employs two major DSB repair pathways, including homologous recombination (HR) and Non-homologous end joining (NHEJ), but the detailed mechanisms of DSB repair remain to be further revealed.

In the first part of this study, we characterized a plasmid-based assay to investigate NHEJ repair in Xenopus egg extracts. Our data argued for a preference for the precise repair by the NHEJ machinery and …

The Role Of Hippo Pathway In Mitosis And Cancer, Xingcheng Chen

Theses & Dissertations

The Hippo signaling pathway has been recently elucidated as a tumor suppressor pathway controlling cell proliferation and apoptosis. The core of this pathway is a kinase cascade which contains MST1/2 (Mammalian sterile 20-like kinase 1/2), LATS1/2 (large tumor suppressor 1/2) and downstream effector named Yes-associated protein (YAP). MST1/2 transduce their kinase activity mainly through directly phosphorylating LATS1/2. Once phosphorylated and activated, LATS1/2 subsequently phosphorylate and inhibit YAP from translocating to nucleus. Current studies involving the Hippo pathway focus on determining its oncogenic role in various organs/tissues. While those studies provide important insight into the tumor suppressor properties of this pathway, …

The Role Of Yes-Associated Protein 1 In Ovarian Physiology And Pathology, Xiangmin Lv

Theses & Dissertations

Ovarian granulosa cells are the major somatic components of the ovarian follicle. Proper proliferation and differentiation of ovarian granulosa cells are essential for successful follicle development. Accumulating evidence indicates that the Hippo-YAP signaling pathway plays critical roles in both development and tumorigenesis of several organs. The present study aims to investigate the role of Yes-associated protein 1 (YAP) in ovarian granulosa cell proliferation, differentiation, and malignant transformation. At first, we found that nuclear YAP (active) was highly expressed in proliferative granulosa cells, whereas cytoplasmic YAP (inactive) was detected mainly in terminally-differentiated luteal cells. Further studies suggested that endogenous YAP activity …

Identifying The Role Of Janus Kinase 1 In Mammary Gland Development And Breast Cancer, Barbara Swenson

Theses & Dissertations

The development of the postnatal mammary gland is tightly controlled by peptide hormones and cytokines. The signaling of these extracellular ligands through their corresponding receptors rely on Janus Kinases (JAKs) that activate downstream Signal Transducers and Activators of Transcription (STATs). The JAK/STAT signaling pathway is crucial for processes such as growth, proliferation, and cell survival of the epithelial tissue, but also for the breakdown and remodeling of the mammary gland via IL-6 class inflammatory cytokines (e.g. LIF and OSM). JAK1 and JAK2, which are expressed in the mammary gland, are thought to have redundant functions. However, our previous studies demonstrated …

The Role Of Ehd2 In Triple-Negative Breast Cancer Tumorigenesis And Progression, Timothy A. Bielecki

Theses & Dissertations

Triple-negative breast cancer (TNBC) comprises 10%-15% of all breast cancer cases, yet is clinically challenging due to lack of targeted therapies which leads to higher mortality. Molecular subtyping has identified the most aggressive subclasses of breast cancer to be enriched in components of caveolae. While caveolae have been linked to many biological processes, their precise role in TNBC is still poorly understood. EHD2, a member of the C-terminal EPS15-Homology Domain-containing (EHD) protein family, has emerged as a new regulator of caveolae dynamics and is essential to maintain a stable membrane pool of caveolae. Studies in model cells demonstrate that caveolae …

Regulation Of Alteration/Deficiency In Activation 3 (Ada3) By Acetylation And Its Role In Cell Cycle Regulation And Oncogenesis, Shashank Srivastava

Theses & Dissertations

The ADA3 (Alteration/Deficiency in Activation 3) protein is a transcriptional adaptor protein that was initially discovered as a component of several HAT (Histone Acetyltransferase) complexes, the enzyme complex responsible for histone acetylation, which is a prerequisite for transcription. Earlier the studies from Dr. Band’s laboratory and that of others’ have deciphered a crucial role of ADA3 in cell cycle regulation (both through G₁/S and G₂/M phase transitions) and in maintaining the genomic stability.

While our laboratory investigated the mechanism behind the role of ADA3 in G₁/S transition, the same remained unknown for G_{2 …}

Role Of Ddr1 In Pancreatic Cancer, Huocong Huang

Theses & Dissertations

Pancreatic ductal adenocarcinomas are highly malignant cancers, characterized by extensive invasion into surrounding tissues, metastasis to distant organs at a very early stage, and a limited response to therapy. One of the main features of pancreatic ductal adenocarcinomas is desmoplasia, which leads to extensive deposition of collagen I. We have demonstrated that collagen I can induce epithelial-mesenchymal transition (EMT) in pancreatic cancer cells. A hallmark of EMT is an increase in the expression of a mesenchymal cadherin, N-cadherin. Our previous studies have shown that up-regulation of N-cadherin can promote tumor cell invasion and that collagen I-induced EMT is through two …

Defining The Role Of Interferon Regulatory Factor 4 In Chronic Lymphocytic Leukemia., Vipul Shukla

Theses & Dissertations

Chronic Lymphocytic Leukemia (CLL) represents the most common adult leukemia in the Western hemisphere. Despite considerable progress in our current understanding of CLL, this disease remains incurable and the molecular events underlying the complex pathogenesis of CLL are not fully elucidated. Interferon Regulatory Factor 4 (IRF4) belongs to the IRF superfamily of transcription factors that has been shown to play critical roles at multiple stages of B cell development. Interestingly, a Genome Wide Association Study identified Single Nucleotide Polymorphism (SNP) mediated IRF4 down regulation, as a major predisposing genetic event during the development of CLL. However, whether low levels of …

Sprouty 2: A Novel Attenuator Of B Cell Receptor And Mapk Signaling In Chronic Lymphocytic Leukemia, Ashima Shukla

Theses & Dissertations

Clinical heterogeneity is a major barrier to effective treatment of Chronic Lymphocytic Leukemia (CLL). Emerging evidence suggests that constitutive activation of various signaling pathways plays a role in the heterogeneous clinical outcome of CLL patients. MAPK-Erk signaling represents one such pathway with a demonstrated role in CLL pathogenesis. In this study, we have investigated the role of Sprouty2 (SPRY2) as a negative regulator of receptor and non-receptor tyrosine kinase signaling in the pathogenesis of CLL. We show that SPRY2 expression is significantly decreased in CLL cells, particularly from poor prognosis patients compared to those from good prognosis patients. Over-expression of …

Role Of Cell Type And Genetic Alterations In Driving Breast Cancer Pathogenesis, Divya Bhagirath

Theses & Dissertations

Breast cancer is the second most leading cause of death among women in the United States. Several environmental and genetic factors contribute to the pathogenesis of the disease. It is classified into different subtypes based on expression of certain markers as well as that of set of genes that define the disease progression and associated mortality. Identification of various subtypes namely: Luminal-like (Luminal-A, Luminal-B), ErbB2 over-expressing, Basal-like and Claudin low types, showed an association of survival outcomes with that of the corresponding gene expression signatures, thus paving a way for therapeutic intervention. It further emphasizes the importance of nature of …

The Role Of Tumor Suppressor Co-Chaperone Chip/Stub1 In Erbb2-Mediated Oncogenesis, Haitao Luan

Theses & Dissertations

The epidermal growth factor receptor (EGFR) family member ErbB2 (Her2) is overexpressed in 20 -30% of invasive breast cancers and this overexpression correlates with poor prognosis and shorter overall as well as disease-free survival. Aberrant expression of ErbB2 through gene amplification, transcriptional deregulation and/or altered endocytic trafficking results in overexpression of ErbB2 at the plasma membrane and biases ErbB2 from primarily ligand-driven hetero-dimerization under normal expression conditions to increased ligand-independent homo-dimer and hetero-dimer formation and consequent activation. C-terminus of HSC70-Inteeracting protein (CHIP)/STIP1-homologous U-Box containing protein 1 (STUB1) is an HSP90/HSC70 interacting negative co-chaperone known to promote ubiquitination and degradation of …

Role Of Hippo-Yap Signaling In Mitosis And Prostate Cancer, Lin Zhang

Theses & Dissertations

The Hippo pathway controls organ size and tumorigenesis by inhibiting cell proliferation and promoting apoptosis. KIBRA [kidney and brain expressed protein] is an upstream regulator of the Hippo-YAP signaling. The role KIBRA plays in mitosis has not been established. We show that KIBRA activates the Aurora kinases during mitosis and KIBRA promotes the phosphorylation of large tumor suppressor 2 by activating Aurora-A. We further show that knockdown of KIBRA causes mitotic abnormalities, including defects of spindle and centrosome formation and chromosome misalignment. The transcriptional co-activator with PDZ-binding motif is a downstream effector of the Hippo tumor suppressor pathway. In the …

Lgr5 Activates Tgfβ Signaling And Suppresses Metastasis In Colon Cancer, Xiaolin Zhou

Theses & Dissertations

Metastasis is the major cause of death in colorectal cancer patients, mainly due to the ineffectiveness of current therapies once metastases begin to form. Further insight into the biology of colorectal cancer metastasis is, therefore, essential in order to gain a greater understanding of this process and ultimately to develop better cancer therapies to prevent or target metastasis. LGR5 is leucine-rich repeat containing G protein-coupled receptor (GPCR) and was discovered as a marker for proliferating adult stem cells in the small intestine. LGR5 and its homologs LGR4 and LGR6 are receptors of R-spondins (RSPOs), which are secreted agonists of canonical …