Medicine and Health Sciences Commons^™

Exploiting Vulnerabilities In The Ras-Rac Signaling Pathway For The Selective Targeting Of Pancreatic Cancer Cells, Neha Chaudhary

Theses & Dissertations

Deregulation of the KRas (Kirsten rat sarcoma virus) GTPase is one of the early hallmarks of Pancreatic Cancer (PC). The most common genetic alteration found in PC are mutations in the KRas protein that block its ability to hydrolyze GTP to GDP and resulting in higher levels of GTP-bound KRas, its active form. Pancreatic tumors driven by oncogenic mutants of KRas tend to be addicted to the oncogene, to the extent that its repression leads to the induction of cell death. This addiction to the KRAS oncogene makes the KRas protein an ideal target for cancer therapy. However, the globular …

Mechanisms By Which Mnte-2-Pyp Suppresses Prostate Cancer Cell Growth, Yuxiang Zhu

Theses & Dissertations

Prostate cancer patients are often treated with radiotherapy. MnTE-2-PyP, is a superoxide dismutase (SOD) mimic and a known radioprotector of normal tissues. Our recent work demonstrates that MnTE-2-PyP also inhibits prostate cancer progression with radiotherapy; however, the mechanisms remain unclear. In this thesis, we identified that MnTE-2-PyP-induced intracellular H2O2 levels are critical in inhibiting growth of prostate cancer cells. We found that MnTE-2-PyP induced protein oxidations in PC3 cells and one major group of oxidized protein targets were involved in energy metabolism. The oxidative phosphorylation rates were significantly enhanced in both PC3 and LNCaP cells with MnTE-2-PyP treatment, but mitochondrial …

The Impact Of Temporal Resolution On Clinical Decision-Making For Individuals With Dysphagia, Shauna Corinne Murray

Speech and Hearing Sciences ETDs

INTRODUCTION: Dysphagia, or a disordered swallow, affects up to 1 in 25 individuals in the United States. The gold standard for assessing dysphagia is the videofluoroscopic evaluation of swallowing (VFES). This allows the clinician to observe the swallow anatomy in motion via an X-ray movie, which historically was recorded at 30 frames per second. In recent years VFES have been performed at less frames per second due to radiation concern. This project investigates the effect of using lower temporal resolutions on assessment of video-fluoroscopic swallow studies.

METHODS: In this investigation, 30 swallow studies, all acquired at 30 frames per second, …

Loss Of Caspase-8 Function In Combination With Smac Mimetic Treatment Sensitizes Head And Neck Squamous Carcinoma To Radiation Through Induction Of Necroptosis., Burak Uzunparmak

Dissertations & Theses (Open Access)

Caspase-8 (CASP8) is one of the most frequently mutated genes in Head and Neck Squamous Carcinomas (HNSCC), and mutations of CASP8 are associated with poor overall survival. The distribution of these mutations in HNSCC suggests that they are likely to be inactivating. Inhibition of CASP8 has been reported to sensitize cancer cells to necroptosis, a unique cell death mechanism. Here, we evaluated how CASP8 regulates necroptosis in HSNCC using cell line models and syngeneic mouse xenografts. In vitro, knockdown of CASP8 rendered HNSCCs susceptible to necroptosis induced by a second mitochondria-derived activator of caspase (SMAC) mimetic, Birinapant, when combined …

Evidence Of Y Chromosome Long Non-Coding Rnas Involved In The Radiation Response Of Male Non-Small Cell Lung Cancer Cells, Tayvia Brownmiller

Graduate Theses, Dissertations, and Problem Reports

Non-small cell lung cancer (NSCLC) is the number one cause of cancer related mortality in the United States and worldwide. Advanced and therapeutically resistant lung tumors contribute to the high rate of mortality from NSCLC, therefore there is a need for new methods of diagnosing and treating this disease. Long non-coding RNAs (lncRNAs) have been shown to be a crucial component of human molecular biology, regulating nearly every cellular pathway from chromatin condensation to transcription and translation. Furthermore, many lncRNAs have been classified as oncogenes or tumor suppressors, highlighting the various molecular mechanisms they are involved in regarding the formation …

Fasting Reduces Intestinal Radiotoxicity Enabling Dose-Escalated Radiotherapy For Pancreatic Cancer, Marimar De La Cruz Bonilla

Dissertations & Theses (Open Access)

Surgical resection is the only potentially curative treatment for pancreatic cancer, but only 15-20% of patients have resectable tumors. In unresectable cases, stereotactic body radiotherapy (SBRT) may be used to give tumor-directed radiotherapy (RT). Unfortunately, this can cause severe gastrointestinal (GI) toxicity due to proximity of the pancreatic head to the duodenum. Protecting the intestine from the toxic side-effects of radiation may enable dose-escalation that could achieve more effective local control of disease. We and others have previously shown that a fast of 24 hours protects mice from lethal doses of the DNA-damaging agent etoposide. In this study, we demonstrate …

Defining The Radioresponse Of Mossy Cells, Devon Ivy

Electronic Theses, Projects, and Dissertations

Clinical radiotherapy is used to treat a variety of brain tumors within the central nervous system. While effective, it can result in progressive and debilitating cognitive impairment that can diminish quality of life. These impairments have been linked to hippocampal dysfunction and corresponding deficits in spatial learning and memory. Mossy cells are a major population of excitatory neurons located within the dentate hilus and highly involved in hippocampal circuitry. They play critical roles in spatial navigation, neurogenesis, memory, and are particularly vulnerable to a variety of neurotoxic insults. However, their sensitivity to ionizing radiation has yet to be investigated in …

Interaction Between Atm Kinase And P53 In Determining Glioma Radiosensitivity, Syed F. Ahmad

Theses and Dissertations

Glioblastoma multiforme (GBM) is the most common primary brain tumor. Studies have shown that targeting the DNA damage response can sensitize cancer cells to DNA damaging agents. Ataxia telangiectasia mutated (ATM) is involved in signaling DNA double strand breaks. Our group has previously shown that ATM inhibitors (ATMi) sensitize GBM cells and tumors to ionizing radiation. This effect is greater when the tumor suppressor p53 is mutated.

The goals of this work include validation of a new ATM inhibitor, AZ32, and elucidation of how ATMi and p53 status interact to promote cell death after radiation. We propose that ATMi and …

Detection And Modeling Of Radiation Induced Effects In Tissues By Dielectric Spectroscopy, Dorin A. Todor

Physics Theses & Dissertations

The work presented here is applied physics research in the field of radiation treatment. We address the development of a new and innovative method, in vivo and possibly non-invasive, for tumor and healthy tissues control during and after the radiation treatment. The radiation treatment is delivered in an almost standardized manner for particular classes of tumors. The large variance in the individual radio sensitivity of healthy tissues and tumors often leads to local recurrence of neoplastic growth and/or distant metastatic disease which often remains untreated. The method is based on the measurement and analysis of electrical impedance data in …