Cancer Biology Commons^™

Kshv Infection Of Endothelial Cells Manipulates Cxcr7-Mediated Signaling: Implications For Kaposi’S Sarcoma Progression And Intervention, Jennifer Totonchy, Lisa Clepper, Janet Douglas, Liron Pantanowitz, Klaus Fruh, Ashlee V. Moses

Pharmacy Faculty Articles and Research

"CXCR7 was recently characterized as an alternative receptor for the chemokine CXCL12/SDF-1, previously thought to bind and signal exclusively through CXCR4.We recently identified CXCR7 as a key cellular factor in the endothelial cell (EC) dysfunction associated with KSHV infection. CXCL12 signaling is critically associated with tumor growth, angiogenesis and metastasis in several diverse tumors and is one of the most studied chemokine/chemokine receptor interactions in cancer systems. The tumorigenic activity of the CXCL12 signaling axis offers an attractive target for therapeutic intervention in multiple cancers including Kaposi’s Sarcoma (KS). However, most of the research to date was based on the …

Effective Non-Viral Delivery Of Sirna To Acute Myeloid Leukemia Cells With Lipid-Substituted Polyethylenimines, Breanne Landry

Pharmacy Faculty Articles and Research

Use of small interfering RNA (siRNA) is a promising approach for AML treatment as the siRNA molecule can be designed to specifically target proteins that contribute to aberrant cell proliferation in this disease. However, a clinical-relevant means of delivering siRNA molecules must be developed, as the cellular delivery of siRNA is problematic. Here, we report amphiphilic carriers combining a cationic polymer (2 kDa polyethyleneimine, PEI2) with lipophilic moieties to facilitate intracellular delivery of siRNA to AML cell lines. Complete binding of siRNA by the designed carriers was achieved at a polymer:siRNA ratio of ~0.5 and led to siRNA/polymer complexes of …

Probing Molecular Mechanisms Of The Hsp90 Chaperone: Biophysical Modeling Identifies Key Regulators Of Functional Dynamics, Anshuman Dixit, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

Deciphering functional mechanisms of the Hsp90 chaperone machinery is an important objective in cancer biology aiming to facilitate discovery of targeted anti-cancer therapies. Despite significant advances in understanding structure and function of molecular chaperones, organizing molecular principles that control the relationship between conformational diversity and functional mechanisms of the Hsp90 activity lack a sufficient quantitative characterization. We combined molecular dynamics simulations, principal component analysis, the energy landscape model and structure-functional analysis of Hsp90 regulatory interactions to systematically investigate functional dynamics of the molecular chaperone. This approach has identified a network of conserved regions common to the Hsp90 chaperones that could …

The Sumo-Targeted Ubiquitin Ligase Rnf4 Regulates The Localization And Function Of The Htlv-1 Oncoprotein Tax, Kimberly A. Fryrear, Xin Guo, Oliver Kerscher, O John Semmes

Arts & Sciences Articles

The Really Interesting New Gene (RING) Finger Protein 4 (RNF4) represents a class of ubiquitin ligases that target Small Ubiquitin-like Modifier (SUMO)–modified proteins for ubiquitin modification. To date, the regulatory function of RNF4 appears to be ubiquitin-mediated degradation of sumoylated cellular proteins. In the present study, we show that the Human T-cell Leukemia Virus Type 1 (HTLV-1) oncoprotein Tax is a substrate for RNF4 both in vivo and in vitro. We mapped the RNF4-binding site to a region adjacent to the Tax ubiquitin/SUMO modification sites K280/K284. Interestingly, RNF4 modification of Tax protein results in relocalization of the oncoprotein from the …

Simulating Molecular Mechanisms Of The Mdm2-Mediated Regulatory Interactions: A Conformational Selection Model Of The Mdm2 Lid Dynamics, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

Diversity and complexity of MDM2 mechanisms govern its principal function as the cellular antagonist of the p53 tumor suppressor. Structural and biophysical studies have demonstrated that MDM2 binding could be regulated by the dynamics of a pseudo-substrate lid motif. However, these experiments and subsequent computational studies have produced conflicting mechanistic models of MDM2 function and dynamics. We propose a unifying conformational selection model that can reconcile experimental findings and reveal a fundamental role of the lid as a dynamic regulator of MDM2-mediated binding. In this work, structure, dynamics and energetics of apo-MDM2 are studied as a function of posttranslational modifications …

Glioblastoma Derived Exosomes Induce Apoptosis In Cytotoxic T Cells Through A Fas Ligand Mediated Mechanism, Keith Sabin, Richard Rovin, Johnathan Lawrence, Robert Belton, Robert Winn

Johnathan Lawrence

INTRODUCTION: Glioblastoma multiforme deploy s a number of weapons to thwart the immune system. Within the tumor microenvironment, cytotoxic T cells fall victim to Fas ligand (FasL) induced apoptosis. In prostate and colorectal cancer, exosomes can mediate this FasL induced T cell apoptosis. Exosomes are tiny, membrane bound vesicles that are released from a cell. They contain functional mRNA and protein and have cell surface molecules representative of their parent cell. It is not known if GBM derived exosomes can also mediate FasL triggered apoptosis. In this study, the role of tumor derived exosomes as the delivery vehicle for FasL …

Leptin Promotes Glioblastoma, Johnathan Lawrence, Nicholas Cook, Richard Rovin, Robert Winn

Johnathan Lawrence

The hormone leptin has a variety of functions. Originally known for its role in satiety and weight loss, leptin more recently has been shown to augment tumor growth in a variety of cancers. Within gliomas, there is a correlation between tumor grade and tumor expression of leptin and its receptor. This suggests that autocrine signaling within the tumor microenvironment may promote the growth of high-grade gliomas. Leptin does this through stimulation of cellular pathways that are also advantageous for tumor growth and recurrence: antiapoptosis, proliferation, angiogenesis, and migration. Conversely, a loss of leptin expression attenuates tumor growth. In animal models …

Effects Of Ss3-Adrenergic Receptor Agonist On Gene Expression Of Leptin In Glioblastoma, Johnathan E. Lawrence, Nicholas J. Cook, Richard A. Rovin, Robert J. Belton, Robert J. Winn

Johnathan Lawrence

In the 25 years since temozolomide entered phase I clinical trials, few new primary or adjuvant therapies have been developed for the treatment of glioblastoma multiforme (GBM) tumors. Our laboratory has been exploring novel methods for the treatment of GBMs. Recent studies indicate that the expression of the hormone leptin and its receptor (OBR) increases in gliomas and positively correlates with the malignancy of the tumor. Interestingly, ß3-adrenergic receptor agonists are known to decrease leptin expression in adipocytes but have not been examined in GBM cells. We hypothesized that b3-adrenergic agonists downregulate the expression of leptin and its receptor. In …

7 Alpha-Hydroxy-Beta-Sitosterol From Chisocheton Tomentosus Induces Apoptosis Via Dysregulation Of Cellular Bax/Bcl-2 Ratio And Cell Cycle Arrest By Downregulating Erk1/2 Activation, Noor Hasima Nagoor

Noor Hasima Nagoor

In continuation of our interest towards the elucidation of apoptotic pathways of cytotoxic phytocompounds, we have embarked upon a study on the anticancer effects of 7 alpha-hydroxy-beta-sitosterol (CT1), a rare natural phytosterol oxide isolated from Chisocheton tomentosus. CT1 was found to be cytotoxic on three different human tumor cell lines with minimal effects on normal cell controls, where cell viability levels were maintained >= 80% upon treatment. Our results showed that cell death in MCF-7 breast tumor cells was achieved through the induction of apoptosis via downregulation of the ERK1/2 signaling pathway. CT1 was also found to increase proapoptotic Bax …

Pentachlorophenol Decreases Tumor-Cell-Binding Capacity And Cell-Surface Protein Expression Of Human Natural Killer Cells, Tasia Hurd, Jasmine Walker, Margaret M. Whalen

Chemistry Faculty Research

Pentachlorophenol (PCP) is an organochlorine pesticide that decreases the tumor-cell killing (lytic) function of human natural killer (NK) cells. NK cells defend against tumor cells and virally infected cells. They bind to these targets, utilizing a variety of cell-surface proteins. This study examined concentrations of PCP that decrease lytic function for alteration of NK binding to tumor targets. Levels of PCP that caused loss of binding function were then examined for effects on expression of cell-surface proteins needed for binding. Exposure to 10 µm PCP for 24 h (which caused a greater than 70% loss of lytic function) decreased NK …

A Shared Gene Expression Signature In Mouse Models Of Ebv-Associated And Non-Ebv-Associated Burkitt Lymphoma, Kathryn T. Bieging, Kamonwan Fish, Subbarao Bondada, Richard Longnecker

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The link between EBV infection and Burkitt lymphoma (BL) is strong, but the mechanism underlying that link has been elusive. We have developed a mouse model for EBV-associated BL in which LMP2A, an EBV latency protein, and MYC are expressed in B cells. Our model has demonstrated the ability of LMP2A to accelerate tumor onset, increase spleen size, and bypass p53 inactivation. Here we describe the results of total gene expression analysis of tumor and pretumor B cells from our transgenic mouse model. Although we see many phenotypic differences and changes in gene expression in pretumor B cells, the transcriptional …

Suppression Of Chronically Induced Breast Carcinogenesis And Role Of Mesenchymal Stem-Like Cells, Kusum Rathore

Doctoral Dissertations

Sporadic breast cancers are mainly attributable to long-term exposure to environmental factors, via a multi-year, multi-step, and multi-path process of tumorigenesis involving cumulative genetic and epigenetic alterations in the chronic carcinogenesis of breast cells from a non-cancerous stage to precancerous and cancerous stages. Epidemiologic and experimental studies have suggested that various dietary compounds like green tea and grape seed may be used as preventive agents for breast cancer control. In this research, I have developed a cellular model that mimics breast cell carcinogenesis chronically induced by cumulative exposures to low doses of environmental carcinogens. I used the chronic carcinogenesis model …

The Utilization Of Mouse Models To Study Gene Functions: The Role Of Foxn3 And Chd2 In Murine Development And Cancer, George Azaz Samaan

Doctoral Dissertations

Murine model organisms are an essential tool in the scientific community quest to decipher the molecular etiology of human diseases. Currently, several methods are used to induce or reproduce human diseases in mouse models using advanced genetic engineering techniques to mutate the wild-type genes. We utilized the Baygenomics gene-trap method to study the effects of two mammalian genes: FOXN3 and CHD2. The Forkhead Box (FOX) family of transcription factors shares a common DNA-binding domain and has been associated with organ development, differentiation, cell growth and proliferation, and cancer. Meanwhile, the CHD (Chromodomain helicase DNA binding protein) family of proteins is …

Regulation Of Hgf Expression By Δegfr-Mediated C-Met Activation In Glioblastoma Cells, Jeannine Garnett

Dissertations & Theses (Open Access)

Overexpression of the hepatocyte growth factor receptor (c-Met) and its ligand, the hepatocyte growth factor (HGF), and a constitutively active mutant of the epidermal growth factor receptor (∆EGFR/EGFRvIII), occur frequently in glioblastoma. c-Met is activated in a ligand-dependent manner by HGF or in a ligand-independent manner by ∆EGFR. Dysregulated c-Met signaling contributes to the aggressive phenotype of glioblastoma, yet the mechanisms underlying the production of HGF in glioblastoma are poorly understood. We found a positive correlation between HGF and c-Met expression in glioblastoma, suggesting that they are coregulated. This is supported by the finding that in a c-Met/HGF axis-dependent glioblastoma …

The Role Of E2f1 In The Response To Dna Double Strand Breaks, Jie Chen

Dissertations & Theses (Open Access)

The importance of E2F transcription factors in the processes of proliferation and apoptosis are well established. E2F1, but not other E2F family members, is also phosphorylated and stabilized in response to various forms of DNA damage to regulate the expression of cell cycle and pro-apoptotic genes. E2F1 also relocalizes and forms foci at sites of DNA double-strand breaks but the function of E2F1 at sites of damage is still unknown. Here I reveal that E2F1 deficiency leads to increased spontaneous DNA break and impaired recovery following exposure to ionizing radiation. In response to DNA double-strand breaks, NBS1 phosphorylation and foci …

Function Of Znf668 In Cancer Development, Ruozhen Hu

Dissertations & Theses (Open Access)

Human cancer develops as a result of accumulation of mutations in oncogenes and tumor suppressor genes. Zinc finger protein 668 (ZNF668) has recently been identified and validated as one of the highly mutated genes in breast cancer, but its function is entirely unknown. Here, we report two major functions of ZNF668 in cancer development.

(1) ZNF668 functions as a tumor suppressor by regulating p53 protein stability and function. We demonstrate that ZNF668 is a nucleolar protein that physically interacts with both MDM2 and p53. By binding to MDM2, ZNF668 regulates MDM2 autoubiquitination and prevents MDM2-mediated p53 ubiquitination and degradation; ZNF668 …

The Role Of Tak1 In Pancreatic Cancer Development, Qianghua Xia

Dissertations & Theses (Open Access)

Pancreatic cancer is the fourth leading cause of cancer-related mortality in the United States and the fifth leading cause of cancer-related mortality worldwide. Pancreatic cancer is a big challenge in large due to the lack of early symptoms. In addition, drug resistance is a major obstacle to the success of chemotherapy in pancreatic cancer. The underlying mechanism of drug resistance in human pancreatic cancers is not well understood. Better understanding of the mechanism of molecular pathways in human pancreatic cancers can help to identify the novel therapeutic target candidates, and develop the new preventive and clinic strategies to improve patient …

The Role Of Receptor Tyrosine Kinase Axl In Pancreatic Ductal Adenocarcinoma And Its Regulation By Hematopoietic Progenitor Kinase 1, Xianzhou Song

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDA) is one of the most aggressive malignancies with less than 5% of five year survival rate. New molecular markers and new therapeutic targets are urgently needed for patients with PDA. Oncogenic receptor tyrosine kinase Axl has been reported to be overexpressed in many types of human malignancies, including diffuse glioma, melanoma, osteosarcoma, and carcinomas of lung, colon, prostate, breast, ovary, esophagus, stomach, and kidney. However, the expression and functions of Axl in PDA are unclear. We hypothesized that Axl contributes to the development and progression of PDA. We examined Axl expression in 54 human PDA samples …

Identification Of Factors Involved In Dna Methylation Of Cpg-Island-Promoters, Yan Zhang

Dissertations & Theses (Open Access)

Repression of many tumor suppressor genes (TSGs) in cancer is mediated by aberrantly increased DNA methylation levels at promoter CpG islands (CGI). About one-fourth of empirically defined human promoters are surrounded by or contain clustered repetitive elements. It was previously observed that a sharp transition of methylation occurs between highly methylated repetitive elements (SINE or LINE) and unmethylated CGI-promoters (e.g. P16, VHL, CDH and RIL) in normal tissues. The functions that lead to increased CGI methylation in cancer remain poorly understood. We propose that CGI-promoters contain cis-elements for triggering de novo DNA methylation. In the first part of our project, …

Mcnamara 2011 Mpmicro - Multi-Probe Microscopy (10/31/2011), George Mcnamara

George McNamara

Multi-Probe Microscopy is an ~1500 page Word document summarizing what I know and/or found interesting in light microscopy, fluorescence microscopy and digital image analysis, from 1995-2005. Very little has been updated since 2005.