Graduation Date

Spring 5-5-2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Programs

Cancer Research

First Advisor

Michael A Hollingsworth

Abstract

Pancreatic cancer is an aggressive form of cancer that is very difficult to detect, treat resulting in a high rate of mortality. Understanding the molecular basis of pancreatic cancer and identifying new molecular targets for designing therapeutic interventions is paramount for improving outcomes in this disease. Notch signaling is a vital developmental signaling pathway that has been implicated to play both oncogenic and tumor suppressive roles in pancreatic cancer. Previous studies from other groups have shown that O-linked glycosylation of Notch signaling plays a key role in the regulation of Notch signaling. Lunatic fringe (Lfng) is one of the glycosyltransferases that modifies the O-fucosylated Notch receptors. Dysregulation of glycosylation mediated by Lfng has been previously shown to result in several Notch-related developmental disorders. While targeting Notch signaling pathway in cancers has been explored as a potential therapeutic intervention for several cancers, the status of Notch-related glycosylation has not been explored.

In the first set of studies, we have characterized the expression pattern of Notch receptors, ligands and Notch-related glycosyltransferases in human pancreatic cancer cell lines and human pancreatic cancer specimens from our Rapid Autopsy Program. These studies identified potential molecular targets in the Notch signaling pathway. Findings of these studies helped identify Lunatic fringe, a Notch-related glycosyltransferase, to have increased expression in human pancreatic cancer. To elucidate the role of Lfng in human pancreatic cancer, we utilized multiple genome editing approaches to engineer three human pancreatic cancer cell lines with a complete lunatic fringe knockout. These cell lines served as model systems to identify the phenotypic changes in pancreatic cancer cells upon loss of functional Lfng gene. Furthermore, we performed next-generation sequencing and polar metabolite analysis to

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help elucidate the impact of Lfng on the transcriptional and metabolic profile of human pancreatic cancer cell lines.

The findings of our study reveal that Lfng impacts the tumorigenicity of pancreatic cancer possibly through global changes in transcription and metabolic reprogramming of cancer cells. These findings of this study provide the basis for further detailed exploration into the role of Notch-related glycosylation in human pancreatic cancer.

Available for download on Wednesday, April 29, 2020

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