Molecular 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. …

Dysregulation Of Mir-10a Promotes Cancer Features In Cholangiocarcinoma, Matthieu Spriet

Theses & Dissertations

Cholangiocarcinoma is a primary liver cancer of the bile duct epithelium that exhibits microRNA-mediated control of tumor cell signaling. Strides toward new treatment rest on a better defining of cholangiocarcinoma tumor biology including the RNA-based layer of regulation. Additionally, there is a gap in knowledge on microRNA expression in human tissue. While there is RNA-seq data of microRNA expression in tissue, it does not differentiate between cell types, thus leaving unanswered questions about cell specific microRNA biology and expression.

Here, we identify miR-10a as an oncogenic microRNA acting through MAPK signaling. Using cholangiocarcinoma cell lines, we determined miR-10a is an …

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 …

Fgfr4 Glycosylation And Processing In Cholangiocarcinoma Promote Cancer Signaling, Andrew J. Phillips

Theses & Dissertations

Cholangiocarcinoma is a cancer of cholangiocytes, or epithelial cells lining the biliary tract. It is associated with a poor prognosis and additional therapeutic treatments are needed to help patients affected by this disease. Fibroblast growth factor receptor 4 (FGFR4) is receptor tyrosine kinase that is involved in various physiologic and pathologic processes. TCGA analysis of thirty different tumor types showed the highest FGFR4 mRNA levels in cholangiocarcinoma. At the protein level, FGFR4 was observed in the majority of cholangiocarcinomas screened and, higher levels were associated with a poorer prognosis. FGFR4 is an N-linked glycosylated receptor tyrosine kinase that we show …

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 …

Hdac1 Is A Required Cofactor Of Cbfβ-Smmhc And A Therapeutic Target In Inversion 16 Acute Myeloid Leukemia, Lisa E. Richter

Theses & Dissertations

Acute myeloid leukemia (AML) is a neoplastic disease characterized by the uncontrolled proliferation and accumulation of immature myeloid cells. A common mutation in AML is the inversion of chromosome 16 [inv(16)], which generates a fusion between the genes for core binding factor beta (CBFB) and smooth muscle myosin heavy chain (MYH11), forming the oncogene CBFB-MYH11. The expressed protein, CBFβ-SMMHC, forms a heterodimer with the key hematopoietic transcription factor RUNX1. Although CBFβ-SMMHC was previously thought to dominantly repress RUNX1, recent work suggests that CBFβ-SMMHC functions together with RUNX1 to activate transcription of specific target genes.

Targeting the …

The Role Of Reactive Oxygen Species In Regulating Macrophage And Fibroblast Activation Within The Breast Cancer Tumor Microenvironment, Brandon J. Griess

Theses & Dissertations

The tumor microenvironment (TME) is a key determining factor in breast cancer, especially the more aggressive subtype triple negative breast cancer (TNBC). The activated fibroblasts and macrophages within the TME have many tumor promoting functions. Therefore, targeting their activation presents a novel therapeutic approach in TNBC. My work studied the role of reactive oxygen species (ROS) during fibroblast and macrophage activation in breast cancer.

My studies showed that expression of the secreted antioxidant enzyme, EcSOD, is silenced in breast cancer samples, in part, via increased promoter methylation. The re-expression of EcSOD inhibited c-Met activation in the TNBC cell line, MDA-MB231. …

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 …

The Role Of Ros In The Progression And Treatment Of Castration-Resistant Prostate Cancer, Dannah R. Miller

Theses & Dissertations

Prostate cancer is the second leading cause of cancer-related deaths in U.S. men, primarily due to the development of castration-resistant (CR) prostate cancer (PCa), of which there are no effective treatment options. Reactive oxygen species (ROS) plays a critical role in prostate carcinogenesis, including the progression of the CR PCa phenotype. ROS regulates both cell proliferation and apoptosis; a moderate increase in ROS can promote proliferation; however, a substantial rise in ROS levels will result in apoptosis. Oxidase p66Shc is elevated in clinical PCa cells and has been associated with a metastatic phenotype of CR PCa cells, promoting PCa cell …

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 …

Developing Targeted Therapy Against Pancreatic Cancer, Garima Kaushik

Theses & Dissertations

Not available.

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 …

Metabolic Reprogramming Of Pancreatic Ductal Adenocarcinoma Cells In Response To Chronic Low Ph Stress, Jaime Abrego

Theses & Dissertations

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal of all cancers with a 5-year survival rate of only 8.2%. This is because PDAC is diagnosed in its advanced stages and is characterized by radio and chemotherapy resistance. Aggressiveness of PDAC tumors is attributed to its high metabolic phenotype, which is characterized by increased glycolysis rate and lactate secretion, while oxidative metabolism is reduced. These metabolic features are required to fulfill the biosynthetic demands of proliferating PDAC cells. However, this increase in metabolic activity results in acidification of the extracellular space because the dense fibrotic stroma of PDAC tumors limits …

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 …

Exploitation Of The Ligand-Binding Properties Of The Mannose 6-Phosphate/Insulin-Like Growth Factor Ii (Igf-Ii) Receptor To Inhibit Igf-Ii-Dependent Growth Of Cancer Cells, Megan Zavorka Thomas

Theses & Dissertations

The mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF2R) is a multifunctional, type I transmembrane receptor that is a member of the P-type lectin family. A large, extracytoplasmic (EC) region of the M6P/IGF2R binds various ligands, allowing the receptor to regulate multiple biological functions, including the role as a tumor suppressor. Two major classes of ligands, M6P-glycosylated (i.e. any proteins that bear M6P due to post-translational modification in the trans-Golgi network (TGN)) and non-glycosylated (i.e., the mitogen insulin-like growth factor II (IGF-II)), bind within distinct regions of the EC of the receptor and are trafficked to the lysosome. The M6P/IGF2R as …

Molecular Mechanisms Regulating Myc And Pgc1Β Expression In Colon Cancer, Jamie L. Mccall

Theses & Dissertations

Identification and characterization of pathways specific to tumor cell survival, but absent in normal tissues, provide opportunities to develop effective cancer therapies with reduced toxicity to the patient. Kinase suppressor of Ras 1 (KSR1) is required for the survival of colorectal cancer (CRC) cells, but dispensable in normal cells. Using KSR1 as a reference standard, we identified EPH (erythropoietin-producing hepatocellular carcinoma) receptor (EPHB4) as a KSR1 functional analog.

We show here that, like KSR1, EPHB4 is aberrantly overexpressed in human CRC cells and selectively required for their survival. Both KSR1 and EPHB4 support tumor cell survival by promoting the expression …