Date of Award

3-26-2026

Embargo Period

6-22-2028

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Pharmacology

College

College of Medicine

First Advisor

Richard Drake

Second Advisor

Peggi Angel

Third Advisor

Anand Mehta

Fourth Advisor

David Lewin

Fifth Advisor

David DeNardo

Sixth Advisor

Michael Ostrowski

Abstract

Pancreatic Ductal Adenocarcinoma (PDAC), a leading cause of cancer related mortality globally, is characterized by an extensive desmoplastic stromal reaction and an altered N-glycome. Stromal collagens and dysregulated N-glycosylation modulate the immune microenvironment, limit nutrient and oxygen diffusion, influence chemotherapy resistance, and promote tumor progression and metastasis. Despite their important roles, little is known about the spatial localization and organization of various extracellular matrix proteins and N-glycans within the PDAC tumor microenvironment.

In this study, Matrix Assisted Laser Desorption Ionization-Mass Spectrometry Imaging (MALDI-MSI) with Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) was utilized to characterize the extracellular matrix proteome and N-glycome of 20 primary PDAC patient tumors, 28 unmatched lung and liver metastases, 21 IPMN, and a 954 patient pancreatic disease tissue microarray in collaboration with the Washington University SPORE in Pancreatic Cancer and Mayo Clinic. This tissue microarray cohort included samples from control, pancreatitis, various premalignancies, and PDAC. Following PNGaseF glycosidase digestion, 214 N-glycan compositions were detected by MALDI-MSI. These tissues were then digested with Collagenase III for detection and localization via peptide MALDI-MSI. Tissues were scraped from the slide and further digested with Collagenase III in solution for peptide ID analysis by LC-MS/MS, resulting in 4,187 putative identified ECM peptides.

Spatially, both ECM peptides and N-glycans uniquely colocalize with various histopathologic features according to multiplex immunohistochemistry. N-glycans with bisecting N-acetylglucosamine structures associated specifically with the invasive tumor front and clusters of immune cell infiltrate, while distinct collagen species from Collagen IV and Collagen II encased tumor cell regions and formed stromal nests surrounding immune cells. N-glycosylation patterns in metastatic PDAC liver and lung samples resembled those of primary tumors, while the ECM proteome of metastases was more similar to their in-situ tissue niches. From this analysis we can visualize the molecular progression of pancreatic disease and begin to link the N-glycome and ECM proteome of PDAC with, immune infiltration, patient survival, treatment response and other clinical variables.

Rights

Copyright is held by the author. All rights reserved.

Download

Available for download on Thursday, June 22, 2028

Share

COinS