Medicine and Health Sciences Commons^™

The Role Of The Hypoxia-Inducible Factor 2 In Pancreatic Cancer: Mechanisms Of Tumor Immunosuppression And Intestinal Radioprotection, Carolina Garcia Garcia

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with dismal prognosis. The only curative option for patients is surgery, but over 80% of patients are not surgical candidates. Unfortunately, PDAC is resistant to the three remaining options. PDAC is characterized by a profoundly hypoxic and immunosuppressive stroma, which contributes to its therapeutic recalcitrance. Alpha-smooth muscle actin+ (αSMA+) cancer-associated fibroblasts (CAFs) are the most abundant stromal component, as well as mediators of stromal deposition. The hypoxia-inducible factors (HIF1 and HIF2) coordinate responses to hypoxia, yet, despite their known association to poor patient outcomes, their functions within the PDAC tumor microenvironment (TME) …

Mucin And Splice Variant Profiles Of Pancreatic Adenocarcinoma Predict Patient Survival And Subtyping, Christopher M. Thompson

Theses & Dissertations

PDAC is a pancreatic epithelial malignancy and demonstrates aggressive progression and bleak patient prognosis. Despite decades of research, the evolution of novel diagnostics and intervention modalities for PDAC is stagnant. This dissertation explores the characteristic aberrant and elevated expression of mucins in PDAC. Beginning with the hypothesis that mucins are associated with disease aggressiveness, analysis of PDAC patient survival in TCGA revealed no associations between single mucin expression and patient survival. This led to the underlying issue of PDAC tumor cellularity since this disease demonstrates variability in the proportion of cancer cells within the tumor. Tumor purity assessed with the …

Biomedical Porcine Models For The Study Of Surgical Hemostasis, Hindlimb Ischemia, And Pancreatic Cancer, Shruthishree Aravind

Theses & Dissertations

Murine models have dominated the world of biomedical research and comparative medicine since their development in the early 1900s. [1] While they may be suitable models to study proteomics and genomics, they may not serve as effective translational models. [2-4] Murine models do not accurately model the pathophysiology of human disease and are limited by their size, application of medical imaging and intervention, which reduces their overall preclinical predictive value. [2-4]

Porcine models on the other hand, are slowly and steadily bridging the gap between murine models and human patients. [5] Pigs …

Vestigial-Like 1 Is A Shared Targetable Cancer-Placenta Antigen Expressed By Pancreatic And Basal-Like Breast Cancers, Sherille Denae Bradley

Dissertations & Theses (Open Access)

Cytotoxic T lymphocyte (CTL)-based cancer immunotherapies have shown great promise for inducing clinical regression by targeting tumor-associated antigens (TAA). To expand the TAA landscape of pancreatic ductal adenocarcinoma (PDAC), we performed tandem mass spectrometry analysis of HLA class I-bound peptides from tumors of PDAC patients. This led to the identification of a shared HLA-A*0101 restricted peptide derived from co-transcriptional activator Vestigial-like 1 (VGLL1), a novel putative TAA demonstrating overexpression in multiple tumor types and low or absent transcript expression in normal tissues with the exception of placenta. VGLL1-specific CTL isolated and expanded from the blood of a male PDAC patient …

Muc4 Based Immunotherapy For Pancreatic Cancer, Kasturi Banerjee

Theses & Dissertations

Pancreatic Cancer (PC) is a lethal disease claiming approximately 45000 lives in the US in 2018, and it establishes an elaborate immunosuppressive tumor microenvironment that aids in disease pathogenesis. Immunotherapy has emerged as a strategy to target tumor cells by reprogramming patient’s immune system. Challenges present in PC immunotherapy are: i) identifying a tumor-associated antigen that could be targeted, ii) identifying adjuvants that could efficiently deliver antigens, iii) eliciting robust anti-tumor responses and iv) overcoming peripheral tolerance and immunosuppression elicited by the tumor.

Firstly, we detected circulating autoantibodies to MUC4 present in PC patients and observed that IgM autoantibodies to …

Defining The Ontogeny And Functions Of Macrophages In Pancreatic Ductal Adenocarcinoma, Yu Zhu

Arts & Sciences Electronic Theses and Dissertations

The immune system plays an essential role in protecting the host organisms against both foreign invaders and self-attacks arisen within the host, such as tumors. Instead of promoting the long-term fitness of the organism, the immune system is often suppressed or hijacked by tumor cells to accelerate the progression of malignancies. Among the key drivers of immune suppression, macrophages are one of the most abundant immune cells present in tumor tissues. High levels of macrophage infiltration in the malignant tissues correlate with negative patient outcome in many types of cancers, including pancreatic ductal adenocarcinoma (PDAC), one of the most lethal …

The Role Of The Diras Family Members In Regulating Ras Function, Cancer Growth And Autophagy, Margie Nicole Sutton

Dissertations & Theses (Open Access)

DIRAS3 is a maternally imprinted tumor suppressor gene that is downregulated by multiple mechanisms across several tumor types. When re-expressed, DIRAS3 decreases proliferation, inhibits motility, and induces autophagy and tumor dormancy. DIRAS3 encodes a 26 kDa small GTPase with 60% homology to Ras and Rap, differing from oncogenic Ras family members by a 34-amino acid N-terminal extension that is required for its tumor suppressive function in ovarian cancer. By assessing the structure-function relationship, I found that DIRAS3 inhibits Ras-induced transformation and is a natural antagonist of Ras/MAPK signaling. DIRAS3 binds directly to Ras and disrupts cluster formation inhibiting the activation …

Pancreatic Ribonuclease Functions As An Epidermal Growth Factor Receptor Ligand Independently Of Its Enzyme Activity And Contributes To Cetuximab Resistance, Heng-Huan Lee

Dissertations & Theses (Open Access)

Ribonuclease (RNase) with its catalytic enzyme activity to degrade RNAs has been shown as a diagnostic serum marker for pancreatic cancer and has also been suspected to have an unidentified cell surface receptor. Epidermal growth factor receptor (EGFR), a well-characterized receptor tyrosine kinase is an effective therapeutic target in multiple cancer types. However, clinical trials targeting EGFR have not demonstrated improved therapeutic efficacy in pancreatic cancer. Here, we show that both bovine pancreatic RNase A (bRNaseA) and human RNase 5 (hRNase5) act as EGFR ligands and directly activate EGFR to promote epithelial-mesenchymal transition. This ligand-like activity is independent of RNases’ …

Acceleration Of The Panin Development In Mice Expressing Oncogenic K-Ras Due To A High Fat Diet, Bincy Philip

Dissertations & Theses (Open Access)

Obesity is postulated to be one of the major risk factors for pancreatic cancer, and recently it was indicated that an elevated body mass index (BMI correlates strongly with a decrease in patient survival. Despite the evident relationship, the molecular mechanisms involved are unclear. Oncogenic mutation of K-Ras is found early and is universal in pancreatic cancer. Extensive evidence indicates oncogenic K-Ras is not entirely active and it requires a triggering event to surpass the activity of Ras beyond the threshold necessary for a Ras-inflammation feed-forward loop. We hypothesize that high fat intake induces a persistent low level inflammatory response …