Browsing by Subject "Cancer Biology"
Now showing 1 - 20 of 40
- Results Per Page
- Sort Options
Item A Clinical Research Study Involving the Use of Erythropoietin in Perioperative Patients Undergoing Surgery for Gynecologic Cancer(2002-07-01) Larson, Sharon Beth; Richardson, Barbara; Martin, MichaelThe purpose of this internship practicum report is to analyze the pathophysiology and impact of anemia in low-income gynecologic cancer patients. The report also assesses the impact of erythropoietin on hemoglobin levels prior to gynecologic cancer surgery. This report is based on a clinical research study to determine whether or not erythropoietin will mitigate the suppression of bone marrow inherent to the gynecologic cancer population and alleviate some of the symptoms and side effects of the anemia.Item A Review of Dendritic Cell Vaccines in Cancer Treatment and a Managerial Focus on Issues Related to Subject Recruitment(2006-12-01) McFarlin, Tory; Arredondo, LaChelle; Gwirtz, Patricia A.; Oglesby, MichaelMcFarlin, Tory. A Review of Dendritic Cell Vaccines in Cancer Treatment and a Managerial Focus on Issues Related to Subject Recruitment. Master of Science (Clinical Research Management), December 2006, 97 pp., 5 tables, bibliography, 24 titles. Melanoma is form of skin cancer that can become deadly if the cancer progresses to a stage of metastasis. Five year survival rates as low as 10% may be noted in such patients. Decarbazine and Proleukin have been approved by the FDA for the treatment of metastatic melanoma; however both have response rates of approximately 20% or less. New treatment modalities including dendritic cell (DC) vaccines are currently being tested for treating metastatic melanoma with greater safety and efficacy profiles. DC vaccines are made by obtaining a subject’s DCs, priming them with melanoma antigen ex vivo and then injecting them into the patient to initiate an immune response against melanoma tumor cells in vivo. Investigational new treatments such has the DC vaccine must first be tested in clinical trials on research subjects. Subject enrollment issues regarding such a trial can cause delays in advances of the treatment. As an intern with a DC vaccine clinical trial, the author assisted in screening 45 patients and observed many hindrances involving enrollment of subjects. Such hindrances include: low rates of study personnel retention, small patient pools, and competing trials. Recommendations to improve enrollment include: more effective advertisement strategies and increased patient education.Item Association of Leukemia and Other Selected Diseases with Occupational Exposure to Welding(2003-05-01) Mendoza, Hilda OraliaMENDOZA, HILDA ORALIA. ASSOCIATION OF LEUKEMIA AND OTHER SELECTED DISEASES WITH OCCUPATIONAL EXPOSURE TO WELDING. Master of Public Health (Epidemiology). May, 2003. Exposure to carcinogens is an established risk factor for cancer development. Welders are chronically exposed to cardinogens. In this study, the relationship between occupational exposure to welding and mortality from leukemia, lymphoma, Hodgkin’s disease, melanoma, lung cancer, or myocardial infarcation was examined. Files from ORISEWDS, Comprehensive Epidemiologic Data Resource, U.S. Department of Energy were utilized to develop a working file including 416,686 records from employees of one or more Oak Ridge, nuclear plant facilities. Neither welding exposure length, radiation exposure, nor smoking were included in this study. Results show higher adjusted ratios (OR) for leukemia, lymphoma, and Hodgkin’s disease for employees occupationally exposed to welding as compared to employees on-occupationally exposed to welding. OR’s for lung cancer and myocardial infarction were also higher for welders than non-welders.Item Astrocyte Elevated Gene-1, a Novel Modulator of Astrocyte Function: Implications for neuroAIDS, aging and glioblastoma(2013-12-01) Vartak, Neha; Ghorpade, AnujaVartak-Sharma, Neha N., Astrocyte elevated gene-1, a novel modulator of astrocyte function: Implications for NeuroAIDS, aging and glioblastoma. Doctor of Philosophy (Biomedical Sciences), Nov, 2013, 180 pp., 1 table, 40 illustrations, 336 bibliographies. Recent attempts to analyze human immunodeficiency virus (HIV)-1-induced gene expression changes in astrocyte identified a multifunctional oncogene, astrocyte elevated gene-1 (AEG-1), as an HIV-1 and tumor necrosis factor-inducible transcript. Subsequently, due to its homology to mouse breast cancer metastasis protein, metadherin, AEG-1 was largely implicated in carcinogenesis of diverse cancer types. However, the role of AEG-1 in astrocytes, the original cell type in which AEG-1 was first identified, still remains to be investigated. In the present study, we identified AEG-1 as a novel modulator of astrocyte function during reactive astrogliosis, neuroinflammation and neurodegeneration, and elucidated its implications in NeuroAIDS, aging and cancer. Our in vitro and in vivo studies recognized AEG-1 modulation of astrocyte migration and proliferation towards the wound site, thereby regulating astrocyte wound healing, a fundamental homeostatic function of astrocytes. Further, AEG-1 expression analyses in HIV-1+ and HIV-1 encephalitic human brain tissues provided the necessary physiological evidence for AEG-1 induction upon HIV-1 neuroinvasion. Herein, we identified AEG-1 as an inflammatory response gene and as an important upstream regulator of NF-κB signaling in astrocytes. Our results demonstrated AEG-1 cytoplasmic and nuclear interaction with NF-κB p65 subunit, which was crucial for NF-κB nuclear translocation, thereby regulating astrocyte neuroinflammation. In the same study, we also identified AEG-1 as a novel regulator of astrocyte glutamate clearance, an important determinant of neurocognitive CNS function, by modulating the expression of the key glutamate transporter, excitatory amino acid transporter 2. Analyses of AEG-1 expression in the cognitive centers of the brain of aging individuals demonstrated AEG-1 age-dependent expression in the human brain, which further proposed a role for AEG-1 in cellular oxidative stress responses. Herein, we identified a novel antioxidant cytoprotective role of AEG-1 in astrocytes and astrocytoma cells. Cellular localization studies by confocal microscopy revealed AEG-1 localization to the dense fibrillar components of the nucleolus in response to injury or oxidative stress, suggesting AEG-1 implication in ribosomal RNA processing. Our results demonstrated AEG-1 regulation of catalase activation and Nrf2 stabilization in response to oxidative stress and further elucidated AEG-1 modulation of Nrf2 nuclear translocation, the first step in antioxidant cellular defense mechanisms. The results presented in this thesis provide insight into the role of oncogene AEG-1 in human astrocytes and ameliorates our understanding of astrocyte-mediated processes in normal and disease-relevant pathologies, ranging from HIV-1-associated neurocognitive disorders and traumatic CNS injuries to primary neoplasms of the brain.Item Characterization of Protein Kinase C in Cisplatin Sensitive and Resistant Human Cervical Cancer HeLa Cells(2000-12-01) Mohanty, Sanghamitra; Basu, Alakananda; Simecka, Jerry; Dimitrijevich, DanMohanty, S., Characterization of protein kinase C in cisplatin sensitive and resistant human cervical cancer HeLa cells. Master of Science (Microbiology and Immunology), December, 2000. 37 pp., 11 illustrations, bibliography, 27 titles. Signal transduction plays a crucial role in carcinogenesis. A defect in signaling, by evading cell death or promoting cell proliferation, may result in neoplastic transformation or protection of cells from the cytotoxicity of anticancer drugs. Therefore, in order to understand the complex mechanism of drug resistance, it is relevant to probe into the important signal transduction pathways. Protein kinase C, a key signal transducer, influences cisplatin sensitivity in many cell lines. We examined whether or not the PKC signal transduction pathway is affected during development of resistance to cisplatin by tumor cells. PKC activators increased cisplatin sensitivity in both parental and cisplatin-resistant cells. Western blot analysis showed a slight decrease in cPKCα and nPKCε, an evaluation in nPKCδ and no change in the abundance of PKCϚ in HeLa/CP cells compared to HeLa cells. Though TPA-induced translocation of PKC isoforms was identical in both cell lines, down regulation of PKCδ was defective in resistant cells. Therefore, a deregulation in PKCδ was associated with cisplatin resistance.Item Clinical Internship with the Division of Gynecologic Oncology at UT Southwestern Medical Center: Carboplatin and Doxil for Gynecologic Cancers(2003-12-01) Epps, Camitria N.; Victoria Rudick; David S. Miller; Barbara RichardsonEpps, Camitria N., Master of Science, Clinical Research Management, December 2003, Carboplatin and Doxil for Gynecologic Cancers, 107 Pages, 9 Tables, 42 titles in Bibliography. Objective: To examine the safety and efficacy of administering the drugs carboplatin and doxil in combination chemotherapy for the treatment of gynecologic cancers, mainly endometrial and ovarian cancer. Materials and Methods: Carboplatin and doxil were previously administered intravenously to 6 patients. Each patient received 3 to 8 cycles of chemotherapy. Doses of carboplatin ranged from 310 mg to 665 mg. The doses of doxil ranged from 54 mg to 80 mg. This is a retrospective study. The 6 patient’s medical charts were reviewed. Data was extracted and a spreadsheet formatted database was created. Results: Data were extracted and a spreadsheet formatted database was created. Results: Due to the small number of patients the results are not statistically significant. 2 patients showed tumor progression while receiving treatment. All patients tolerated doses very well and experienced minimal toxicities. Conclusion: Carboplatin plus doxil combination chemotherapy given intravenously has a potent effect on endometrial and ovarian cancers. Studies using this chemotherapy for the treatment of gynecologic cancers should be conducted on a wider scale to access the statistical significance of the treatment.Item Combined Chemo/Anti-Angiogenic Cancer Therapy in Lewis Lung Metastases(2002-05-01) Sinha-Datta, Anjuli; Goldfarb, Ronald H.; Agarwal, Neeraj; Mathew, Porunelloor A.Datta, Anjuli. Combined Chemo/Anti-Angiogenic Cancer Therapy in Lewis Lung Metastases. Master of Science (Microbiology and Immunology), May 2002. 41 pp., 17 illustrations, bibliography. The focus of my dissertation studies is an eight amino acid peptide (Å6) derived from the non-receptor binding region of urokinase plasminogen activator (uPA), which partially inhibits the binding of uPA to its receptor (uPAR). Å6 has been synthesized as a potential novel anti-cancer agent and kindly provided by Ångstrom Pharmaceuticals, Inc. (San Diego, CA). We further examined potential therapeutic properties of Å6 in vivo and in vitro. Å6 appeared to directly inhibit the invasion of Lewis lung carcinoma cells through Matrigel by approximately 40-45% compared to control. In addition, Å6 had a morphological effect resulting in thicker tubes on small vessel endothelial tube formation compared to no treatment. Interestingly, doxorubicin had similar effects when added to growing endothelial cells. Moreover, Å6 was administered alone and in combination with a standard clinically used chemotherapeutic agent, doxorubicin, in a Lewis lung carcinoma mouse model to test possible synergy between an anti-angiogenic compound (Å6) and a chemotherapeutic agent. This is the first observation that Å6 has the potential to display a direct anti-metastatic therapeutic effect for established pulmonary metastases in this model. Therefore, we believe that Å6 in combination with doxorubicin has the potential to provide better therapy to cancer patients with tumor metastases than potent chemotherapeutics agents alone, by increasing the dose of non-toxic Å6 and reducing the recommended dose of doxorubicin.Item Defining the Prostate Cancer Population in Texas Using Hospital Discharge Data(2004-05-01) Manuel, Christopher J.; Karan Singh; Antonio A. ReneManuel, Christopher J., Defining the prostate cancer population in Texas using hospital discharge data. Masters of Public Health (Biostatistics), May 2004, 25 pp., 6 tables, bibliography, 35 titles. The Texas Health Care Information Council (THCIC) was created by the 74th Texas Legislature in 1995. THCIC’s primary purpose is to provide data that will enable Texas consumers and health plan purchasers to make informed health care decisions. This data also serves the purpose of providing information about disease trends and hospital discharges. The purpose of this study was to describe the disease status of prostate cancer in the state of Texas. Prostate cancer is the most common non-cutaneous male malignancy and ranks as the second cause of cancer-related mortality among men in the United States. Epidemiologic data was extracted from the data set for analysis looking at disease trends based on a variety of factors such as age, race, and insurance.Item Detection of Androgen Receptors by Flow Cytometry(2008-05-01) Dutta, Mayurika; McClain, Robert; Singh, Meharvan; Hall, StanDutta, Mayurika, ‘Detection of androgen receptors by Flow Cytometry’. Internship Practicum report, Biotechnology, May 2008, 80 pp., 1 table, 18 figures. The use of androgen therapy is expanding given the documented potential benefits like increasing bone mineral density, muscle mass and strength. Androgen therapy also has potential risks including increasing the likelihood of prostate cancer and cardiovascular disease. So, we need a way to differentiate those who are likely to be benefitted by the therapy and those that are not. Data from Dr. Meharvan Singh’s lab has shown that activation of intracellular androgen receptors triggers cell survival pathways, while activation of the membrane androgen receptor suppresses cytoprotective pathways, and thus promotes cell death. We propose to develop a diagnostic kit that measures the relative ratio of intracellular androgen receptors and membrane androgen receptors, which is predicted to gauge relative risks or benefits associated with androgen therapy.Item Dissecting the Role of Protein Kinase C-Epsilon in Breast Cancer(2013-12-01) Jain, Kirti; Basu, AlakanandaProtein kinase C-epsilon (PKCε) has pro-tumor functions in many cancers including breast cancer. The purpose of this dissertation is to understand the role of PKCε in fundamental processes that are associated with breast cancer development and progression. PKCε is known to promote the survival of breast cancer cells. Autophagy is a process of cellular self-digestion that can mediate cell survival during stress. We have found that PKCε overexpression increases the basal autophagy in breast cancer cells while its depletion reduces it. Moreover, the effect of PKCε on autophagy is isozyme specific. Regulation by PKCε is not limited to basal autophagy as it also mediated starvation-induced autophagy. Looking for the possible mechanisms, we found that PKCε negatively regulates mammalian target of rapamycin (mTOR), which is the master regulator of autophagy. These results show that PKCε positively regulates autophagy, likely, via inhibition of mTOR. PKCε overexpression in mammary epithelial cells led to morphological changes indicating its role in regulation of cell plasticity. Further analysis revealed that PKCε promotes epithelial to mesenchymal transition (EMT), which is an early step in cancer metastasis. In addition, PKCε mediated transforming growth factor-beta (TGFβ)-induced EMT partially via Snail, which is a crucial EMT effector. Moreover, PKCε promoted cell migration and anoikis Ii resistance which are hallmarks of EMT. To examine the phenotypic effect of PKCε manipulation in a physiologically relevant context, we employed three dimensional (3D) cell culture model. We found that PKCε overexpression led to disruption of acinar morphogenesis in 3D culture. These results indicate a causal role for PKCε in breast tumor development and progressionItem EGCG and Its Role in Prostate Cancer Angiogenesis(2005-05-01) Thomas, Rusha; Porunelloor Mathew; Ming-Chi Wu; Dan DimitrijevichThomas, Rusha, EGCG and its role in prostate cancer angiogenesis. Master of Science (Biochemistry and Molecular Biology), May 2005, 47 pages, 14 illustrations, reference list, 44 titles. Hypoxia inducible factor-1 (HIF-1)-mediated upregulation of vascular endothelial growth factor (VEGF) has been implicated in angiogenesis associated with malignancies. HIF-1 consists of a constitutively expressed HIF-1β subunit, and a hypoxia-inducible HIF-1α subunit. Hypoxic induction of HIF-1α correlates with increased transcriptional activation of its downstream target genes, including VEGF. Epidemiologic and laboratory studies indicate that green tea has cancer preventive activity which has been attributed to its polyphenol components, the major one being epigallocatechin gallate (EGCG). This study investigated the effect of EGCG on normoxic VEGF expression in PC-3ML human prostate cancer cells. In contrast to previous studies where EGCG inhibited VEGF expression in breast and colon cancer cell lines, our results demonstrated that EGCG has the ability to upregulate HIF-1α transcription factor via inhibition of prolyl hydroxylation and subsequent von Hippel-Lindau protein interaction. HIF-1α upregulation by EGCG led to increased VEGF promoter activity and protein expression.Item Extracellular Proliferating Cell Nuclear Antigen as a Marker and Therapeutic Target for Cancer Stem Cells.(2014-05-01) Horton, Nathan C.; Porunelloor MathewCancer is the second leading cause of death in the United States, making it a major public health issue. Due to increased efficiency in detecting and treating cancer, primary tumors account for only 10% of cancer mortalities. Today, the majority of cancer related deaths are due to metastasis and relapse after therapy, which current cancer treatments fail to prevent. Recently, cancer stem cells (CSCs) have emerged as being responsible for metastasis and relapse. CSCs are cancerous cells with stem cell characteristics including self renewal and the ability to evade chemotherapy and elimination by the immune system. A part of the innate immune system, Natural Killer (NK) cells provide the first line of defense against cancerous cells. NK cells kill cancerous cells through release of cytotoxic granules, a process regulated by activating and inhibitory receptors at the NK cell surface recognizing specific surface molecules on a tumor. Of the NK cell receptors, signaling via NKp44 is pivotal in determining the fate of tumor cells because it possesses both activating and inhibitory functions and is only expressed on activated NK cells. In this study, expression of Proliferating Cell Nuclear Antigen (PCNA), an inhibitory ligand of NKp44, is identified on the surface of a Diffuse B Cell Lymphoma, Prostate, and Breast cancer cell lines in novel association with Human Leukocyte Antigen Class I molecules. By blocking interactions between NKp44 and the PCNA/HLA I complex, NK cell mediated cytotoxicity and IFN-γ secretion is enhanced. Finally, prostate and breast cancer cells expressing PCNA at the cell surface express several molecular signatures of cancer stem cells which increase the ability of these cells to survive the metastatic process.Item Function and Regulation of the Natural Killer Cell Receptor 2B4 (CD244)(2005-05-01) Vaidya, Swapnil V.; Porunelloor A. Mathew; Richard Easom; Hriday DasThe purpose of these studies was to investigate two issues related to the natural killer (NK) cell receptor, 2B4 (CD244) – its in vivo function and transcriptional regulation. In previous in vitro studies, ligation of 2B4 with a monoclonal antibody enhanced the cytotoxicity of NK and CD8 T cells against various tumor cell lines, indicating that 2B4 is an activating receptor. To study the role of 2B4 in vivo, 2B4 deficient (2B4-/-) mice were used. The initial characterization of the 2B4-/- mice indicate a thymic developmental defect with an increase in the immature CD4-/CD8- population in the thyme of female but not male mice. NK cells from the 2B4-/- mice were impaired in activation by IL-2 as compared to wild type NK cells. These results suggest a role of 2B4 in lymphoid development. The in vivo role of 2B4 in tumor rejection was studied in a mouse tumor model in which melanoma cells were injected intravenously and pulmonary metastases enumerated 14 days later. The murine melanoma cell line, B16, was stably transfected with CD48, the counter-receptor for 2B4. Using CD48+ and CD48- B16 cells in tumor experiments indicated that 2B4 functioned as an inhibitory receptor. In addition, a gender-specific role of 2B4 in the rejection of B16 melanoma cells was discovered. 2B4-/- male mice cleared B16 cells more efficiently than wild type male mice, while female 2B4-/- mice were impaired in controlling tumor growth as compared to wild type female mice. In vitro and in vivo studies indicate a complex role for NK cells in the mechanism of this gender effect. Several studies have shown that the expression of 2B4 is upregulated during viral infections and under certain cytokine stimulation. Previously, it has been shown activator protein-1 (AP-1) plays an important role in the transcription of the 2B4 gene. In this study an Ets transcription factor was shown to upregulate the transcription of the gene. This element functions in an AP-1 dependent manner. Stimulation of surface 2B4 down-regulates its own expression by decreasing the activity of the Ets element in the 2B4 promoter. These studies identify a role of 2B4 in lymphoid development and tumor rejection in vivo. The gender-specific defect in 2B4 knock-out mice implicates its role in lupus. The transcriptional studies provide insights into the regulation of 2B4 gene.Item Gender Differences in Hemoglobin Level at the Onset of Symptoms of Cancer-Related Anemia(2003-12-01) Levar, Joshua M.; Victoria RudickLevar, Joshua M., Gender Differences in Hemoglobin Level at the Onset of Symptoms of Cancer-Related Anemia. Masters (Clinical Research Management), December, 2004, 39 pp., 2 tables, 5 illustrations, bibliography, 47 titles. The purpose of this study was to assess whether the previously demonstrated relationship between quality of life and anemia in cancer patients was influenced by gender. Two hundred and fifty one patients of various diagnoses completed the Functional Assessment of Cancer Therapy – Anemia (FACT-An) subscale to measure quality of life. Regression analysis revealed a significant positive correlation between hemoglobin and FACT-An subscale score, as well as a negative correlation between Eastern Cooperative Oncology Group (ECOG) performance status and FACT-An subscale score. Mean comparison demonstrated a significant difference in FACT-An score between patients currently and not currently receiving chemotherapy. An analysis of covariance, controlling for current therapy and ECOG performance status as confounders, found that men score more poorly on the FACT-An within the hemoglobin range of 10.-13.0 g/dL. In conclusion, the normalization of hemoglobin levels improves quality of life; however, gender differences should be taken into account when determining optimal hemoglobin levels.Item Health Risk, Behavior and Attitudes of Urban African American Men Toward Prostate Cancer Screening(2006-05-01) Samuel, Prattus; Sue Lurie; Kristine Lykens; Sejong BaeSamuel, Prauttus K., Health Risk, Behavior and Attitudes of Urban African American Men Toward Prostate Screening. Master of Public Health (Community Health), May 20, 2006, 84 pp., 10 tables, 1 illustration, 72 references. In Texas, prostate cancer is the second leading cause of cancer death among non-Hispanic whites and African American (AA) males. This thesis addresses the research questions: what psycho-social characteristics associated with men who participate in prostate screening? What psycho-social and clinical characteristics are associated with reported risk factors? Focus groups were conducted to identify attitudes, perceptions and health beliefs of African American men’s early detection behavior. Existing data from a prostate screening program in Dallas County, Texas was analyzed to determine associations of demographic variables, risk factors variables and screening participation for each subgroup with AA as the group of interest. Comparison of responses and data analysis provided the framework for a conceptual model.Item HIF: A Key Survival Factor for Serum-Deprived Prostrate Cancer Cells(2008-05-01) Thomas, Rusha; Jamboor Vishwanatha; Harlan Jones; Raghu KrishnamoorthyThomas, Rusha, HIF: A key survival factor for serum-deprived prostate cancer cells. Doctor of Philosophy (Molecular Biology and Immunology), May 2008, 134 pages, 47 illustrations, reference list, 105 titles. The hypoxia-inducible factor (HIF) is central to hypoxic adaptation of tumors, and consists of an oxygen-labile HIF-1α and a constitutively expressed HIF-1β subunit. In specific aim 1, we report that prolonged serum deprivation is a potent inducer of HIF-1α in PC-3 and LNCaP prostate cancer (PCa) cells, despite normal oxygen conditions. In contrast, cells grown in the presence of serum did not upregulate HIF-1α protein levels. Moreover, HIF-1α protein increase during serum deprivation correlated with increased cell survival, while suppression of HIF-1α expression significantly decreased PCa cell viability. Our results further demonstrate that HIF-1α protein increase during serum deprivation is due to increased HIF-1α protein synthesis. First, there was no significant increase in HIF-1α mRNA. Secondly, cycloheximide, a protein synthesis inhibitor, prevented HIF-1α protein increase in serum-deprived PCa cells. Moreover, the expression of HIF-1α-target genes, VEGF and IGF-2, was concomitantly increased in serum-deprived PCa cells, while suppression of HIF-1α expression markedly inhibited their induction. Most interestingly, our study showed a significant decline in PCa cell survival following inhibitor of IGF-2 activity. Taken together, our study demonstrates for the first time that PCa cells counteract the stress of prolonged serum deprivation by upregulating HIF-1α protein which increases IGF-2 expression to promote cell survival. In specific aims 2 and 3, we investigated the molecular mechanism of autocrine regulation of HIF-1α, IGF-2 and cell survival in serum-deprived PC-3 and LNCaP PCa cells. We detected a time-dependent increase in Akt activation during serum deprivation, and inhibition of Akt activation attenuated the serum deprivation-mediated increase in HIF-1α and cell survival. Importantly, IGF-2 secretion significantly increased during serum deprivation, and was accompanied by increased activation of its receptor, insulin-like growth factor-I receptor (IGF-IR). Additionally, inhibition of IGF-2 activity markedly suppressed the serum deprivation-mediated increase in IGF-IR and Akt activation, HIF-1α expression, as well as its own transcription, suggesting autocrine regulation of HIF-1α expression via IGF-2. Reciprocal regulation of the IGF-2/IGF-IR system and P13K-Akt pathway was further demonstrated by findings wherein Akt activation was prevented following suppression of IGF-IR expression, and IGF-IR activation was inhibited following P13K inhibition. Lastly, HIF-1α suppression abolished the serum deprivation-mediated increase in Akt activation, and also resulted in higher IGF-IR protein levels indicating reduced IGF-IR activation. Collectively, our study demonstrates that a HIF-1α-dependent autocrine feedback loop upregulates HIF-1α, and thus promotes survival of normoxic, serum-deprived PCa cells.Item Investigation of Proteasome Chymotryptic Activities and Effects on their Inhibition in Rat and Human Natural Killer Cells(2003-04-01) Lu, Min; Goldfarb, Ronald H.; Borejdo, Julian; Easom, RichardLu, Min, Investigation of Proteasome Chymotryptic Activites and Effects of Their Inhibition in Rat and Human Natural Killer Cells. Doctor of Philosophy (Biochemistry and Molecular Biology), April, 2003, 185 pp., 3 tables, 32 illustrations, bibliography, 158 titles. The proteasome is a multicatalytic proteinase complex that is involved in the major extralysosomal pathway responsible for intracellular protein degradation in mammalian cells. This dissertation focuses on investigating proteasome chymotryptic activities and the effects of selective inhibitors of these activities on the function of natural killer (NK) cells. In this dissertation, 20S proteasomes derived from rat RNK16 cells were purified and some of their biochemical and biophysical properties were investigated extensively. The results indicated that RNK16 cell-derived proteasome differ from the proteasome of other origins in many aspects including substrate selectivity, inhibitor specificity, and kinetic regulation, although they may share some common biochemical properties with others. To investigate the effects of proteasomal inhibition on the function of NK cells, several proteasome inhibitors were used including MG115, MG132, clasto-lactacystin-β-lactone, EGCG and LLnL. MG115 and MG 132 were shown to induce apoptosis of RNK16 cells, as evidenced by DNA fragmentation, caspase-3 activation and the appearance of sub-G1 cell populations. Activation of multiple caspases and increased expression of cell surface Fas (CD95) protein were also observed following the treatment of RNK16 cells by these two inhibitors. This dissertation also tested the hypothesis that different cell types could respond differentially to proteasome inhibitors. The effects of several proteasome inhibitors were determined on the purified 20S proteasomal and 26S proteasomal chymotrypsin-like activity in whole cell extracts and intact YT and Jurkat cells, human NK and T cell lines respectively. Following such treatment, caspase-3 activation occurred much earlier in Jurkat cells than YT cells; cell cycle analysis indicated a sub-G1 apoptotic cell population in Jurkat cells and G2/M arrest in YT cells. In addition, accumulation of p27 and IκB-α was detected only in Jurkat cells, but not YT cells. Therefore, proteasome inhibitors appear to act differentially in cell cycle progression and apoptosis signaling pathways between human NK and T cells. These studies indicate that the generation of ideal proteasome inhibitors for the treatment of malignancies could be screened or designed to specifically induce cancer cells to undergo programmed cell death, while having little or no apoptosis-inducing abilities for natural killer cells and other cells of the immune response, thus enhancing the selectivity and specificity of the anti-cancer, apoptosis-inducing capabilities of proteasome inhibitors.Item Involvement of Caspase-2 in Cisplatin-Induced Cell Death in 2008 Ovarian Cancer Cells(2008-04-01) Adkins, Brett T.; Basu, Alakananda; Berg, Rance E.; Gryczynski, ZygmuntAdkins, B., Involvement of caspase-2 in cisplatin-induced cell death in 2008 ovarian cancer cells. Master of Science (Molecular Biology and Immunology) April, 2008, 59 pp., 12 illustrations, bibliography, 73 titles. Cisplatin, one of the most effective anticancer drugs in the treatment of ovarian cancer, causes DNA damage and leads to apoptosis. Caspases, a family of cysteine proteases, are essential for the induction of apoptosis. Initiator caspases activate effector caspases to trigger apoptosis. Caspase-2 can function as both an initiator and effector caspase although there are controversies regarding its role in DNA damage-induced apoptosis. Caspase-2 is the only caspase constitutively located in the nucleus, although its function there is unknown. In the present study we have investigated if caspase-2 is important during cisplatin-induced apoptosis and whether cisplatin treatment affects the localization of caspase-2. Caspase-2 depletion suggested that caspase-2 acts upstream of caspase-2 acts upstream of caspase-9 in cisplatin-induced apoptosis. We also made a novel observation that rottlerin, an inhibitor of DNA damage-induced apoptosis, specifically downregulates caspase-2 via the ubiquitin proteamose-mediated pathway. We further show that cisplatin induces caspase-2 translocation out of the nucleus. Moreover, translocation of caspase-2 is more important for cisplatin-induced cell death.Item Involvement of Estrogen Receptor Beta 5 in the Progression of Glioma(2013-05-01) Li, Wenjun; Shaohua YangEmerging evidence suggests a decline of ERβ expression in various peripheral cancers and ERβ has been proposed as a cancer brake that inhibits tumor cell growth and proliferation. In the current study, we have identified ERβ5 as the predominant isoform of ERβ in human glioma and its expression was significantly increased in human glioma as compared with non-neoplastic brain tissue. Hypoxia and activation of hypoxia inducible factor (HIF) increased ERβ transcription in U87 cells, suggesting elevated ERβ expression in glioma might be induced by the hypoxic stress in the tumor. Overexpression of either ERβ1 or ERβ5 increased PTEN expression and inhibited activation of the PI3K/AKT/mTOR pathway; ERβ5 also inhibited the MAPK/ERK pathway. In U87 cells, ERβ1 and ERβ5 decreased cell proliferation and decreased cells in the S+G2/M phase. Our findings suggest hypoxia induced ERβ5 expression in glioma as a self-protective mechanism against tumor proliferation and that ERβ5 might serve as a therapeutic target for the treatment of glioma. We also reported potential association between ERβ expression and outcomes of TMZ or tamoxifen treatment for GBM, which might be of practical clinical values.Item Involvement of S6 Kinase in Breast Cancer(2013-12-01) Sridharan, Savitha; Basu, AlakanandaSridharan, S., Involvement of S6 Kinase in Breast Cancer. Doctor of Philosophy (Cancer Biology), November 2013, 129pp, 19 illustrations, 215 references. The 40S ribosomal protein S6 Kinase (S6K) is activated downstream of the mammalian target of rapamycin (mTOR)and is believed to play and important role in protein translation. In mammalian cells S6K is represented by two highly homologous proteins, S6K1 and S6K2. Both homologs have been shown to be amplicfied and over expressed in breast cancer cells and tissues. While the regulation and functions of S6K1 have been addressed, little is known about those of S6K2 . Hence we sought to examine the causes and consequences of elevated S6K2 levels in breast cancer cells. While the depletion of S6K1 decreased breast cancer cell death, silencing of S6K2 substantially increased it in response to apoptotic and chemotherapeutic agents. We then explored the mechanism by which S6K2 mediates survival and observed that in contrast to S6K1, S6K2 depletion decreased the activation of the prosurvival protein Akt and increased the level of proapoptotic proteins p53 and bid. Following this observation, we sought to determine the pathways(s) contributing to the overexpression of S6K2 in breast cancer cells. Due to its role as a prognostic indicator in estrogen receptor (ER) – positive tumors, we studied the role of the estrogen signaling pathways in regulating S6K2 levels. Estradiol and estrogen receptor alpha (ERα) positively regulated S6K2 protein but did not affect its mRNA levels, suggesting post-transcriptional regulation. We further observed that S6K2 regulated cell survival downstream of estrogen in ER-positive breast cancer cells. These findings strongly suggest that S6K2 is critical for the survival of breast cancer cells and that targeting S6K2 in combination with chemotherapeutic agents is a novel strategy to promote breast cancer cell death.