Medicine and Health Sciences Commons^™

Rna-Seq Reveals Transcriptomic Program Associated With Stemness In Taxane Resistant Prostate Cancer, Christina K. Cajigas-Du Ross

Loma Linda University Electronic Theses, Dissertations & Projects

There is no cure for advanced prostate cancer (PCa), and taxane chemotherapy is the only treatment option once other therapies have failed. However, this is problematic since all patients eventually develop chemoresistance. Emerging treatments for advanced PCa have shown promise at the benchside, but clinical trials have not resulted in newly approved drugs due in part to redundant survival pathways utilized by prostate tumor cells to maintain therapy-resistance. Using RNAsequencing—an innovative approach for quantifying gene expression changes—this dissertation sought to elucidate chemoresistance-associated molecular pathways as a catalyst to develop new therapeutic targets. Results revealed a differential upregulation of stemness-associated genes …

Comparative Studies Of Tslp And Il-7 In Normal Early Human Neonatal And Adult B Cell Development, Terry-Ann Milford

Loma Linda University Electronic Theses, Dissertations & Projects

Defining the role of cytokines in promoting human B cell development is important for understanding B cell leukemia and for developing strategies to restore B cell production that is lost during some therapies. The purpose of this study was to investigate the roles of the IL-7R ligands, thymic stromal lymphopoietin (TSLP) and IL- 7, in the early stages of normal postnatal and adult human B cell development. Using novel in vitro and in vivo model systems, we show that TSLP and IL-7 are able to expand B cell precursors individually and in combination from CB hematopoietic stem cells. In this …

Cd21 And Cd24 Co-Expression: A Translational Model Between Mouse And Human, Abigail Benitez

Loma Linda University Electronic Theses, Dissertations & Projects

Systemic Lupus Erythematosus and Rheumatoid Arthritis are B cell-mediated autoimmune diseases that afflict millions of people worldwide. B cell-targeted therapies for these diseases result in variable clinical outcomes. Thus, a need exists to better understand the dynamics of human B cell production and function. The mouse model has provided a foundation for understanding the mechanisms involved in human B cell development and autoimmune disease. However, differences in mouse and human B cells are not fully understood. Our work shows that the co-expression of CD21 and CD24, determined by 7-color flow cytometry, can be used to demarcate developmental subsets of B …

Small Molecule Inhibitors Of Hpv16 E6, Chung-Hsiang Yuan

Loma Linda University Electronic Theses, Dissertations & Projects

High-risk human papillomaviruses (HR-HPVs) cause nearly all cases of cervical cancer. HPV 16 E6, one of two viral oncogenes, protects cells from apoptosis by binding to and accelerating the degradation of several apoptotic proteins, including caspase 8 and p53. We proposed that blocking the interactions between HPV E6 and its partners using small molecules had the potential to re-sensitize HPV+ cells to apoptosis. To test this prediction, we screened libraries of small molecules for candidates that could block E6/caspase 8 binding, and identified several candidates from different chemical classes. Testing hits for dose-dependency and specificity in vitro and for toxicity …

Regulation Of Pim1 Under Hypoxia In Prostate Cancer, Eva Sahakian

Loma Linda University Electronic Theses, Dissertations & Projects

A defining characteristic of solid tumors is the capacity to divide and spread under conditions of nutrient deprivation and limited oxygen availability. These microenvironmental stresses arise from structural abnormalities in tumor vessels that lead to aberrant microcirculation. Hypoxia acts as a physiological “selection pressure” in the progression of cancer by activating pathways and enhancing the expression of specific genes in tumor cells which eventually diminish their apoptotic potential. Ultimately, hypoxic microenvironment functions as a “stress factor”, selecting cells with the ability to survive and divide under anoxic conditions. The members of the PIM family of cytoplasmic serine threonine kinases are …

Fetal Programming By Nicotine Increases Cardiac Susceptibility To Ischemic Injury, Jennifer Charlotte Alexie Lawrence

Loma Linda University Electronic Theses, Dissertations & Projects

Fetal programming is the area of study that focuses on the prenatal origins of adult onset disorders. Previous studies have associated an adverse prenatal environment with the onset of physiologic and metabolic diseases during adulthood. Fetal malnutrition, hypoxia, and exposure to drugs - such as cocaine and nicotine - have been associated with adult disease states. Cigarette smoking is the number one cause of preventable death in the developed world. Among the many dangerous chemicals found in tobacco products is nicotine, the compound responsible for the addictive nature of tobacco use. Nicotine use during pregnancy is a known cause of …

Localization And Expression Of The Aer Receptor In Escherichia Coli, Daniel Salcedo

Loma Linda University Electronic Theses, Dissertations & Projects

In Escherichia coli, chemotactic movement towards an energetically-favorable environment is mediated by five transmembrane chemoreceptors. These sensory proteins respond to numerous environmental signals, including amino acids, sugars, and pH. The aerotaxis receptor, Aer, is an intracellular sensor that responds to oxygen concentration and other parameters affecting cellular energy levels. Bacterial chemotaxis receptors form dimeric signaling units that organize into tetramers and hexamers and form large clusters at the cell poles. A cluster arrangement could increase receptor sensitivity by lateral communication between dimers, thus amplifying the signal from one dimer. We have shown that Aer forms dimers, trimer of dimers, …

Oxidative Stress-Mediated Anticancer Activity Of Novel Ahr Modulators Af & 5f203, Lancelot S. Mclean

Loma Linda University Electronic Theses, Dissertations & Projects

Estrogen receptor positive (ER+) breast cancer tends to respond to anti-estrogen agents such as Tamoxifen. Approximately 40% of ER+ breast cancer is resistant to these agents and those that initially respond often acquire resistance. Estrogen receptor negative (ER-) breast cancer remains largely unresponsive to these agents. It is therefore vital to discover drugs that are potent in both forms of breast cancer. Aminoflavone, (5-amino-2, 3-fluorophenyl)-6,8-difluoro-7-methyl-4H-l-benzopyran-4-one; AF; NSC 686288) and 5F203, (2-[-Amino-3-methy phenyl]-5-flurobenzothiazole) are novel anticancer candidate agents that display potent in vitro and in vivo anti-proliferative activity against select human tumor cells with a unique anticancer activity profile in the …

Novel Binding Domains Mediate Binding Of Hpv 16 E6 To Fadd And Procaspase 8, Sandy S. Tungteakkhun

Loma Linda University Electronic Theses, Dissertations & Projects

To evade the host response to infection, viruses have developed means to survive and propagate. HPV 16, a causative agent of cervical cancer and of some cases of oropharyngeal cancers, is one example. We have reported that the early viral protein E6 binds to proteins necessary for propagation of the apoptotic signal following receptor/ligand interactions, such as those mediated by FADD DED and procaspase 8 DED. E6 expression leads to the dose-dependent accelerated degradation of FADD and the protection of E6-expressing cells from Fas-induced apoptosis. Surprisingly, the splice isoforms of E6, E6_large and E6*, affect the stability of procaspase …

Mechanisms Of T Helper Cell Modulation In A Simulated Space Radiation Environment, Asma Rizvi

Loma Linda University Electronic Theses, Dissertations & Projects

Exposure to solar particle events (SPEs) poses the most serious threat to astronaut health. Due to this radiation environment, exploration of the solar system beyond Earth’s orbit entails many risks for the crew on these deep space missions. Depression or dysfunction of the immune system is a major concern due to its high radio-sensitivity; potential consequences include overwhelming infection, development of cancer, fibrosis, and poor wound healing. Astronauts are also exposed to low dose/low dose rate (LDR) radiation. A three month stay at the international space station exposes them to ~ 0.05 Gy of radiation.

C57BL/6 mice received LDR gamma-radiation …

Radiation-Induced Increases In Pkc Modulate Integrin Expression And Contribute To Fibrotic Changes, Pinal Rushikesh Pandya

Loma Linda University Electronic Theses, Dissertations & Projects

The sequences of events in fibrosis are similar to those in wound healing; however, the normal termination and resolution stages do not take place. The initial cellular response following ionizing radiation involves accumulation of the ECM (extracellular matrix) including collagen, fibronectin and the interaction of many growth factors (cytokines) with their receptors. There are a number of unanswered questions regarding many aspects of radiation-induced fibrosis, including the initial triggers and physical changes that initiate the process. We have confirmed that elevated pKC and other cellular changes following radiation are similar to those found at sites of inflammation. This information leads …

The Effect Of Radiation And Repeated Sub-Culturing On Tgf-Β1 Signaling In Frtl-5 Cells, Cheryl G. Burrell

Loma Linda University Electronic Theses, Dissertations & Projects

From our ongoing in vitro studies using the Fisher Rat Thyroid cell line-5 (FRTL-5) we recorded accelerated growth, reduced follicularization and reduction in thyroxin release that occurred as the cells were repeatedly sub-cultured. We also recorded that these changes occurred earlier and more rapidly following radiation exposure. We determined that TGF-β1 production increased under both conditions. We hypothesized that alteration in the TGF-β1 signaling pathway contributed to the changes observed in the cellular properties of FRTL-5 cells. Our objective was to examine some of the players in the TGF-β1 signaling pathway to determine whether radiation and/or repeated subculturing promoted changes …

An In Vitro Model Of Ovarian Cancer: Studying The Effects Of Talc And Pycnogenol®, Amber Renée Buz'zard

Loma Linda University Electronic Theses, Dissertations & Projects

Ovarian cancer is the sixth most common cancer and accounts for more deaths than any other cancer of the female reproductive system. The American Cancer Society has suggested that poor diet, talc and industrial pollutants may increase the risk of developing ovarian cancer. Talc is ubiquitous and concern is raised about its safety, role as a possible carcinogen and known ability to cause irritation and inflammation. Due to the silent nature of ovarian cancer, chemoprevention is a high priority. The most useful chemopreventive compounds will inhibit, delay or reverse carcinogenesis, and can be taken for long periods of time with …

Influence Of Human Papillomavirus 16 E6 On Trail-Mediated Apoptosis, Theodore O. Garnett

Loma Linda University Electronic Theses, Dissertations & Projects

Viruses have developed sophisticated strategies to evade host defenses and facilitate the production and spread of progeny. HPV 16, whose immune evasion activities can contribute to cervical cancer, is a prime example of such a virus. In this study, we examined the influence of HPV 16 E6 on TRAIL-induced FADD-dependent and -independent pathways in two cellular models: HCT116 colon carcinoma cells and U2OS osteosarcoma cells. We show that transfection of the HPV 16 E6 oncogene into HCT116 cells provides protection from TRAIL-mediated apoptosis. Additionally, we demonstrate that the protection provided by E6 is dose-dependent because higher levels of E6 provide …

The Potential Role Of Ledgf/P75 In Prostate Cancer, Tracy Ruth Daniels

Loma Linda University Electronic Theses, Dissertations & Projects

The serum autoantibody repertoire from cancer patients is currently being exploited for the identification of tumor associated antigens (TAA) and the design of TAA arrays. Such arrays would facilitate autoantibody profiling and potentially aid in the serological diagnosis and prognosis of tumors. The goal of this study was to identify and characterize prostate-specific TAA. We observed that while the general frequency and titers of autoantibodies in PCa patients were relatively similar to those in matched controls, significant differences could be detected between the two groups in the autoantibody response to the lens epithelial-derived growth factor p75 (LEDGF/p75). LEDGF/p75 is a …

Ionizing Radiation And Endostatin Gene Therapy Against Lung Tumor, Xian Luo

Loma Linda University Electronic Theses, Dissertations & Projects

Although many advances have been made in radiotherapy, tumor radioresistance and normal tissue damage continue to always be important issues for radiation oncologists. Numerous reports have also documented that radiation exposure increases the risk for malignancy and suppresses immune mechanisms. However, increasing evidence has suggested that anti-angiogenic therapy that targets tumor blood supply may alter abnormal tumor vasculature, thus synergizing radiotherapy. The governing hypothesis of the present study was that modification of tumor vasculature by antiangiogenic gene therapy can increase the efficacy of radiotherapy and that radiation can also improve DNA transfection efficiency by increasing expression of the administered gene. …

Potential Mechanisms Explaining The Antitumor Effect Of Total-Body Irradiation, Glen Michael Miller

Loma Linda University Electronic Theses, Dissertations & Projects

While numerous reports have documented that radiation exposure increases the risk for malignancy and suppresses immune mechanisms, increasing evidence has suggested that low-dose total-body irradiation (TBI) may alter leukocyte composition and function leading to heightened immune responsiveness and long-term remission of certain cancers. Having observed that moderate-dose TBI produces an antitumor effect in the Lewis lung carcinoma (EEC) model, the major goal of this study was to determine whether changes in tumor growth could be correlated with radiation-induced alterations of immune system parameters. The governing hypothesis was that selective immune augmentation, i.e. upregulation of specific leukocyte subsets, is primarily responsible …

Development Of A Model For Infective Endocarditis Via Intravenous Injection And Tooth Infection Of Rats Using Pathogenic Bacteria, Shahrokh Shabahang

Loma Linda University Electronic Theses, Dissertations & Projects

Historically, focal areas of infection have been linked to a number of systemic ailments. During the early part of the 20th century, patients who were suffering from inexplicable diseases and who were suspected of having infected teeth were referred to the dentist for multiple extraction of their dentition. The discovery of antibiotics provided a false sense of security that the war against microorganisms is no longer a concern for mankind. However, more recently, it has become common belief that increasing numbers of systemic diseases are linked to chronic infections. Recovery of bacteria from representative tissues has led investigators to believe …

A Novel Strategy Utilizing Co-Expression Of Murine Il-12 And Antisense Tgf-Pl Against H238 Tumor Formation, Craig A. Seheult

Loma Linda University Electronic Theses, Dissertations & Projects

Cytokines have a profound effect on immune modulation, thus playing a significant role in cancer gene therapy. A variety of human carcinomas secrete transforming growth factor-beta (TGF-β), a cytokine with potent immunosuppressive properties. Suppressing TGF-β could be a key to successfully combating malignancies, such as gliomas, mammary, and colon cancers, that over-express TGF-β. Conversely, interleukin-12 (IL-12) is a potent immunostimulatory cytokine capable of regulating T and NK cell-mediated cytotoxic responses (Trinchieri, 1994) during an anti-tumor response. Activation of the immune system with such immunostimulatory cytokines renders it inert to the suppressive effects of TGF-β. To better understand these processes our …

Effects Of Liposome-Encapsulated Tnf-Alpha And Radiation Against Colon Cancer, Dong Won Kim

Loma Linda University Electronic Theses, Dissertations & Projects

Previous studies have shown that tumor necrosis factor-α (TNF-α) can augment the antitumor effects of radiation, inhibiting tumor progression to a greater extent than either modality alone. However, nonspecific toxicities associated with TNF-α have limited its use as an adjuvant. This limitation is potentially resolved with the encapsulation of TNF-α in sterically stabilized, PEGylated liposomes (STEALTH®). Thus, the overall hypothesis of the research was that the combination of radiation with STEALTH® liposome encapsulated TNF-α (SL-TNF-α) will have greater efficacy and fewer dose-limiting side effects in the LS174T human colorectal tumor xenograft model compared to the combination of free TNF-α and …

Vaccinia Virus-Mediated Glioma Gene Therapy Using P53, Il-2 And Il-12, Bing Chen

Loma Linda University Electronic Theses, Dissertations & Projects

Malignant brain tumors are generally lethal soon after their diagnosis, and the five-year survival rate for the patient is low in spite of neurosurgery, radiation therapy, and/or chemotherapy. Gene therapy has the potential to improve patient survival and quality of life by delivering specific combinations of therapeutic genes directly to the tumor for localized treatment.

We have based our cancer gene therapy for glioma on a highly attenuated variant of the Lister strain of vaccinia virus (VV) which has been proven to be a safe and effective vaccine vector. Other advantages include a wide host range, a strong promoter system, …

Connexin-32 Contributes To Radiation Resistance In Thyroid Follicles, Da-Thao Dinh Tran

Loma Linda University Electronic Theses, Dissertations & Projects

The objective of this study was to examine the role of gap junctions in the radiation resistance of thyroid follicles. The question of whether gap junctional intercellular communication plays an important role in the “contact effect”, wherein cells in direct apposition are more resistant to the damaging effects of radiation, has been debated for years. We used the Fischer rat thyroid cell line (FRTL-5) to carry out our experiments. This thesis is divided into two parts: 1) characterization of gap junctional properties in FRTL-5 cells and, 2) exposure of these cells to radiation.

We found that, unlike primary thyroid cells, …

Interactions Of Igf-Ii And Cathepsin D In Mcf-7 Breast Cancer Cells, Jesika S. Faridi

Loma Linda University Electronic Theses, Dissertations & Projects

A primary role of the IGF-II/M6P receptor is to target lysosomal enzymes from the golgi to the lysosomes. This receptor has distinct binding sites for IGF-II and M6P, however, reciprocal interactions between these ligands have been observed (Kiess et al. 1989, 1990). Since IGF-II modulates the routing of cathepsin D in MCF-7 cells by blocking the intracellular binding of cathepsin D to the IGF-II/M6P receptor (De León et al. 1996), we hypothesized that expressing a mutant form of IGF-II that does not bind the IGF-II/M6P receptor will not interfere with lysosomal enzyme trafficking.

In our present study, we report the …

Expression And Requirement Of Epithelial Fatty Acid- Binding Protein In Neuronal Axon Growth, Gregory William Allen

Loma Linda University Electronic Theses, Dissertations & Projects

Epithelial fatty acid-binding protein (E-FABP) is expressed in the dorsal root ganglia following sciatic nerve injury and in migrating and differentiating neurons during neuronal development. It was hypothesized that E-FABP expression is required for the robust outgrowth of axons from developing and regenerating neurons. To test this hypothesis, E-FABP expression in both PC12 cells and primary retinal neurons was examined. In PC12 cells, NGF induces E-FABP mRNA and protein during the period of neurite outgrowth, and E-FABP localizes to the perinuclear cytoplasm, nucleus, and growth cone. Furthermore, E-FABP-deficient cell lines exposed to NGF were less differentiated and had shorter neurites …

The Role Of Brn-3.2 In Retinal Ganglion Cell Differentiation, Jerin Marie Wright

Loma Linda University Electronic Theses, Dissertations & Projects

Within the retina, the POU domain of transcription factors brn-3.0, brn-3.1, and brn-3.2 are present only in retinal ganglion cells. These genes are believed to be involved in establishing neural cell lineages in mammals. In this study brn-3.2 was examined by comparing the number of ganglion cells present during postnatal development in normal mice (+/+), in mice homozygous (-/-) for the brn-3.2 gene, and in adult mice with a heterozygous gene deletion (+/-) for brn-3.2. Optic nerve cross sections were imaged by electron microscopy, and axon profiles counted systematically by hand. These counts were then related to the nerve cross …

A Preclinical Model Of Ionizing Radiation And Tnf-Alpha Gene Therapy For Cancer, Jun Li

Loma Linda University Electronic Theses, Dissertations & Projects

Long term control of high-grade brain tumors is rarely achieved with current therapeutic regimens. This study sought to determine if pretreatment with plasmid DNA expressing Tumor Necrosis Factor-α (TNF-α) could enhance the effect of ionizing radiation in an aggressive, rapidly growing glioma tumor (C6) model. Plasmid DNA is an attractive vector system for delivery of foreign genes into eukaryotic cells due to its advantages including low immunogenicity in vivo, lesser toxicity and relatively low cost. We have constructed a plasmid-based mammalian expression vector (pGL1-TNF) to secrete human TNF-α from cancer cells. Plasmid DNA was successfully transfected into C6 cells …

Antitumor Effect Of Il-2, P53, And Bax Naked Gene Transfer In C6 Glioma Cells, Peyman Haghighat

Loma Linda University Electronic Theses, Dissertations & Projects

[Abstract not included]

Dna-Dna Checkerboard Hybridization To Identify Bacteria In Human Plaque Samples, Jasan Lee Zimmerman

Loma Linda University Electronic Theses, Dissertations & Projects

Previous research has shown that using DNA probes to identify the presence of specific bacteria in human plaque samples is superior to the commonly used anaerobic cultural procedures. Some periodontal pathogens are either uncultivable or very difficult to grow, such as Prevotella intermedia, P. nigrescens, and Eubacterium brachy. Digoxygenin probes were prepared for 15 oral bacteria. These probes were used with a checkerboard DNA-DNA hybridization scheme to analyze whether human plaque samples contained any of the 15 bacterial species. Our results have shown that this method is successful in identifying bacterial DNA present in the subgingival patient plaque …

A Model Using Radiation And Pws4-Htnf-Α Gene Therapy For Treatment Of Glioblastomas, Angelo G. Baher

Loma Linda University Electronic Theses, Dissertations & Projects

The efficacy of radiotherapy for cancer is limited by the dose that can be safely delivered to the tumor without causing debilitating side effects. In addition, successful treatment of highly malignant tumors such as glioblastomas is likely to require adjunctive therapies to enhance tumor response to radiation. Previous studies have shown immunomodulation and a synergestic reduction in tumor volume of malignant tumors when tumor necrosis factor-α (TNF-α) protein is administered prior to radiation. The major goal of the present investigation was to evaluate the efficacy of pWS4-human TNF-α (pWS4-hTNF-α), a new plasmid construct that expresses human TNF-α protein, together with …

Study Of The Hiv-1 Gene Regulatory Proteins Tat And Rev By The Two-Hybrid System In Yeast, David Allen Elkins

Loma Linda University Electronic Theses, Dissertations & Projects

Tat and Rev, small proteins encoded by the Human Immunodeficiency Virus type 1 (HIV-1), regulate its pattern of gene expression within infected cells. Tat increases transcription from the integrated pro virus by approximately a thousand-fold; Rev effects a shift in the pattern of splicing of the viral mRNA. Both are likely to interact with cellular proteins in executing their respective functions. Tat has additional activities (including neurotoxicity and inhibition of lymphocyte activation) which may be extraneous to its viral functions.

In order to identify cellular proteins interacting with Tat and Rev, the genes for both were cloned into plasmid vectors …