Cell Biology Commons^™

Characterization Of Stem Cell Turnover In A Living Epithelial Bilayer, Elizabeth Sumner

Dissertations and Theses (Open Access)

Homeostatic maintenance of epithelia requires the renewal and replacement of old or dying cells while sustaining a functional barrier. Imbalance between cell production and elimination are hypothesized to underlie many pathological conditions. However, our knowledge of cell turnover within living tissues remains largely restricted to static images due to the limited ability to study epithelia in their native context. Here we report that clearance of damaged basal stem cells promotes compensatory proliferation of neighboring stem cells to maintain overall population numbers in a bilayered epithelium. Time-lapse imaging and electron microscopy experiments reveal that dying cells are rapidly cleared as nearby …

The Roles Of Malt1 In Nf-Κb Activation And Solid Tumor Progression, Deng Pan

Dissertations and Theses (Open Access)

The transcription factor NF-κB plays a central role in many aspects of biological processes and diseases, such as inflammation and cancer. Although it has been suggested thatNF-κB is critical in tumorigenesis and tumor progression, the molecular mechanism by which NF-κB is activated in solid tumor remains largely unknown. In the current work, we focus on growth factor receptor-induced NF-κB activation and tumor progression, including epidermal growth factor receptor (EGFR)-induced NF-κB in lung cancer and heregulin receptor (HER2)-induced NF-κB in breast cancer. We found that Mucosa-associated lymphoma translocation protein 1 (MALT1), also known as paracaspase, is required for EGFR-induced NF-κB activation …

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

Dissertations and 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. …

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 …

The Apoptotic And Inhibitory Effects Of Phylloquinone In The U937 Cell Line, Tesha E. Blair

Electronic Theses and Dissertations

Phylloquinone is a natural analog of vitamin K that has been shown to both inhibit cancer cell growth and induce apoptosis in several cancer cell lines. This study examined these effects in a non-Hodgkin lymphoma cell line, known as U937. Cell growth inhibition and apoptosis were assessed through the quantification of cell density and area, following treatment with several concentrations of phylloquinone. In addition, apoptosis was detected and quantified using immunofluorescent markers of apoptosis (i.e. annexin V, APO-BrdU). Treatment with phylloquinone resulted in reduced overall cell density, increased overall cell area, and an increased frequency of apoptosis in U937 cells. …

Drosophila Models To Investigate The Role Of Regulation Of Cell Death In Development And Cancer, Anam Hussain

Honors Theses

Cell death is of key importance in maintaining health and normal development. In cancer, cell death is improperly controlled provoking uncontrolled proliferation of cells, which results in severe harm to the body. The Hippo pathway is an identified pathway in Drosophila melanogaster that is involved with regulating the different mechanisms of survival and proliferation within the cells. It is known to interact with a gene known as Dronc that is a key participant in the cell death pathway of apoptosis. Previous work has shown how the loss of certain caspases, which are cysteine proteases, is linked with cell survival. My …

Identification Of Potential Drug Targets In Cancer Signaling Pathways Using Stochastic Logical Models, Peican Zhu, Hamidreza Montazeri Aliabadi, Hasan Uludag, Jie Han

Pharmacy Faculty Articles and Research

The investigation of vulnerable components in a signaling pathway can contribute to development of drug therapy addressing aberrations in that pathway. Here, an original signaling pathway is derived from the published literature on breast cancer models. New stochastic logical models are then developed to analyze the vulnerability of the components in multiple signalling sub-pathways involved in this signaling cascade. The computational results are consistent with the experimental results, where the selected proteins were silenced using specific siRNAs and the viability of the cells were analyzed 72 hours after silencing. The genes elF4E and NFkB are found to have nearly no …

P-Rex1 Promotes Resistance To Vegf/Vegfr-Targeted Therapy In Prostate Cancer, Hira Lal Goel, Bryan Pursell, Leonard D. Shultz, Dale L. Greiner, Rolf A Brekken, Craig W. Vander Kooi, Arthur M. Mercurio

Molecular and Cellular Biochemistry Faculty Publications

Autocrine VEGF signaling is critical for sustaining prostate and other cancer stem cells (CSCs), and it is a potential therapeutic target, but we observed that CSCs isolated from prostate tumors are resistant to anti-VEGF (bevacizumab) and anti-VEGFR (sunitinib) therapy. Intriguingly, resistance is mediated by VEGF/neuropilin signaling, which is not inhibited by bevacizumab and sunitinib, and it involves the induction of P-Rex1, a Rac GEF, and consequent Rac1-mediated ERK activation. This induction of P-Rex1 is dependent on Myc. CSCs isolated from the PTEN^pc−/− transgenic model of prostate cancer exhibit Rac1-dependent resistance to bevacizumab. Rac1 inhibition or P-Rex1 downregulation increases the …

Decorin As A Multivalent Therapeutic Agent Against Cancer., Thomas Neill, Liliana Schaefer, Renato V. Iozzo

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Decorin is a prototypical small leucine-rich proteoglycan that epitomizes the multifunctional nature of this critical gene family. Soluble decorin engages multiple receptor tyrosine kinases within the target-rich environment of the tumor stroma and tumor parenchyma. Upon receptor binding, decorin initiates signaling pathways within endothelial cells downstream of VEGFR2 that ultimately culminate in a Peg3/Beclin 1/LC3-dependent autophagic program. Concomitant with autophagic induction, decorin blunts capillary morphogenesis and endothelial cell migration, thereby significantly compromising tumor angiogenesis. In parallel within the tumor proper, decorin binds multiple RTKs with high affinity, including Met, for a multitude of oncosuppressive functions including growth inhibition, tumor cell …

Lim Protein Ajuba Participates In The Repression Of Atr-Mediated Dna Damage Response In Human Cells, Sampada Kalan

Dissertations, Theses, and Capstone Projects

LIM proteins constitute a superfamily characterized by the presence of specialized domains called LIM. LIM domain is a unique double-zinc finger motif found in a variety of proteins and is mainly involved in protein-protein interactions. Previous work has implicated that members of the Zyxin subfamily of LIM proteins, namely TRIP6 and LPP are involved in the repression of the DNA damage response (DDR) at telomeres. We further explore if another member from this family has an influence on DDR prevention in the cells. Here, we describe a novel role for Ajuba, a Zyxin family LIM protein, in repressing inappropriate activation …

Uncovering New Roles For The Aryl Hydrocarbon Receptor (Ahr) In Breast Cancer, Justin Kirk Tomblin

Theses, Dissertations and Capstones

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that is responsive to many exogenous and endogenous ligands. AHR is of particular interest in cancer, and has been shown to play roles in tumor progression. As such, it has received growing attention as a possible chemotherapeutic target. Obesity increases the risk of breast cancer, complicates treatment of breast cancer, and stimulates the growth of larger, more aggressive mammary tumors. Many breast tumors in obese women are estrogen receptor (ER)-positive and, while targeting hormone receptors like ER is beneficial, many obese women see a recurrence of their cancer after standard …

Hexokinase Ii Localization Is Independent Of Ampk Activation In Hela Cells, Alyssa Brown

Graduate School of Biomedical Sciences Theses and Dissertations

In order for a cancer cell to thrive, it must alter its metabolism to produce the energy needed for rapid growth. Cells accomplish this by the Warburg Effect, or switching metabolism to aerobic glycolysis, where a cell can rapidly break down sugar into ATP, lactic acid and additional byproducts. Hexokinase 2, the enzyme that catalyzes the first committed step of glycolysis, may also be upregulated in cancer cells to increase glucose breakdown. Similar proteins for metabolism are found in both S. cerevisiae and mammalian cells. S. cerevisiae regulates metabolism through glucose repression, by Snf1 (mammalian homolog: AMPK) activation, which aids …

The Cytotoxic Synergy Of Nanosecond Electric Pulses And Low Temperature Leads To Apoptosis, Claudia Muratori, Andrei G. Pakhomov, Elena C. Gianulis, Sarah D. Jensen, Olga N. Pakhomova

Bioelectrics Publications

Electroporation by nanosecond electric pulses (nsEP) is an emerging modality for tumor ablation. Here we show the efficient induction of apoptosis even by a non-toxic nsEP exposure when it is followed by a 30-min chilling on ice. This chilling itself had no impact on the survival of U-937 or HPAF-II cells, but caused more than 75% lethality in nsEP-treated cells (300 ns, 1.8-7 kV/cm, 50-700 pulses). The cell death was largely delayed by 5-23 hr and was accompanied by a 5-fold activation of caspase 3/7 (compared to nsEP without chilling) and more than 60% cleavage of poly-ADP ribose polymerase (compared …

The Role Of E-Cadherin Force In The Maintenance Of Homeostasis In Epithelial Acini, Fnu Vani Narayanan

Theses and Dissertations

Numerous three-dimensional model systems have emerged for emulating the biochemical and physiological states of native tissue. Yet little is known about the effects of mechanical forces on cell behavior in the context of an organized tissue structure in three-dimensional cell-culture. Epithelial cells cultured in a three-dimensional environment comprised of extracellular matrix proteins form spheroids of polarized cells. Cellular responses to mechanical cues, generated from dynamic interactions with the extracellular matrix and neighboring cells, are known to influence cellular behavior to a great extent. Previous studies have shown that tumorigenic progression has been frequently linked to the down regulation of E-cadherin, …

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 …

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 …

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 …

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 …

Detection Of Ubiquitination On Syk And Documenting Syk Stability, Izabela Mazur, Wen Horng Wang, Robert J. Geahlen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Post-translational modifications regulate the activities of proteins important to numerous diseases. Spleen Tyrosine Kinase (Syk) is particularly interesting to researchers because it modifies many targets and plays multiple roles in regulating cells in our bodies and its abnormal modifications may contribute to cancer, Alzheimer’s disease and allergies. In an attempt to study these modifications of Syk, we first looked at detecting ubiquitination on Syk protein. Ubiquitin, a small 8 kDa molecule, attaches to lysine residues on protein. The attachment of ubiquitin to Syk may cause Syk to either propagate signals onwards to activate other proteins or signal it to undergo …

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 …

The Role Of The Pleckstrin Homology Domain-Containing Protein Ckip-1 In Activation Of P21-Activated Kinase 1 (Pak1), Yong-Bae Kim, Yong Jae Shin, Adhiraj Roy, Jeong-Ho Kim

Biochemistry and Molecular Medicine Faculty Publications

Upon growth factor stimulation, PAK1 is recruited to the plasma membrane and activated by a mechanism that requires its phosphorylation at S223 by the protein kinase CK2. However, the upstream signaling molecules that regulate this phosphorylation event are not clearly defined. Here, we demonstrate a major role of the CK2α-interacting protein CKIP-1 in activation of PAK1. CK2α, CKIP-1 and PAK1 are translocated to membrane ruffles in response to the epidermal growth factor (EGF), where CKIP-1 mediates the interaction between CK2α, and PAK1 in a PI3K-dependent manner. Consistently, we observe that PAK1 mediates phosphorylation and modulation of the activity of p41-Arc, …

Targeting Neddylation Induces Dna Damage And Checkpoint Activation And Sensitizes Chronic Lymphocytic Leukemia B Cells To Alkylating Agents, C Paiva, J C. Godbersen, A Berger, J R. Brown, A V. Danilov

Dartmouth Scholarship

Microenvironment-mediated upregulation of the B-cell receptor (BCR) and nuclear factor-κB (NF-κB) signaling in CLL cells resident in the lymph node and bone marrow promotes apoptosis evasion and clonal expansion. We recently reported that MLN4924 (pevonedistat), an investigational agent that inhibits the NEDD8-activating enzyme (NAE), abrogates stromal-mediated NF-κB pathway activity and CLL cell survival. However, the NAE pathway also assists degradation of multiple other substrates. MLN4924 has been shown to induce DNA damage and cell cycle arrest, but the importance of this mechanism in primary neoplastic B cells has not been studied. Here we mimicked the lymph node microenvironment using CD40 …

Analyzation Of Metabolic Reprogramming In Drug-Resistant Mcf-7 Cells, Derick Han, Ho Leung, Andrew Vo

Student Scholar Symposium Abstracts and Posters

The Warburg effect states that cancer cells mainly receive their energy from anaerobic glycolysis. Thus, mitochondria play a different role in the metabolism of cancer cells as opposed to normal, healthy cells. In chemotherapy, there is always a chance of the cancer regressing. Making drug-resistant cancer cells to analyze their metabolism may change how cancer is treated. This study aimed to create drug-resistant MCF-7 cell lines with doxorubicin in order to determine the metabolic changes that have occurred in the process of becoming resistant to drug treatments.

Deciphering The Functional Collaboration Of Mid And Bric-A-Brac 2 As Potential Regulators Of Cellular Proliferation Within Adult Drosophila Ovaries, Petra Visic

Master's Theses

Stem cell niches are highly organized and specialized microenvironments located within specific tissues of both vertebrate and invertebrate organisms [1]. In Drosophila melanogaster, three distinct stem cell niches have been identified within the ovary including the germline stem cell (GSC), follicle stem cell (FSC), and escort stem cell (ESC) niche. Recently, Fregoso-Lomas et al. [2] reported that Gurken/Epidermal Growth Factor Receptor (EGFR) signaling is modulated within posterior ovarian follicle cells by Midline (Mid). The mid gene encodes a T-box transcription factor protein that specifies cell fates in the developing heart [3][4], central nervous system [5][6], epidermis [7], and eye …

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 …

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 …

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 …

Activating The Msh2/Msh6 Apoptotic Pathway In Cancer Cells Using Non-Reserpine Compounds, Jacob M. Mauceri

Honors College Theses

DNA mismatch repair (MMR) is a system that is highly conserved in both prokaryotes and eukaryotes. The heterodimeric protein MutSα and a suite of associated proteins are essential in the recognition and repair of DNA afflicted with mispaired bases and short insertion/deletion loops, but are also implicated in funneling damaged cells towards apoptosis via a key conformational change in a subunit of the MutSα complex. This conformation can be bound specifically by the small molecule reserpine. Molecular dynamics modeling and virtual screening were used to identify additional small molecule novel ligands with the predicted ability to selectively bind this “death” …