Proteomic Analysis of Post-Translational Modifications and Signaling Pathways in Pancreatic Cancer

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dc.contributor.advisorGao, Xiaolian
dc.contributor.committeeMemberBawa-Khalfe, Tasneem
dc.contributor.committeeMemberFrigo, Daniel E.
dc.contributor.committeeMemberGunaratne, Preethi H.
dc.creatorVo, Hiep T. 1990-
dc.date.accessioned2019-12-17T04:08:23Z
dc.date.createdDecember 2019
dc.date.issued2019-12
dc.date.submittedDecember 2019
dc.date.updated2019-12-17T04:08:24Z
dc.description.abstractSignaling pathways mediated by receptor tyrosine kinases (RTKs) and protein kinases play essential roles in cellular physiology. Src Homology 2 (SH2) domains bind to specific phosphotyrosine motifs and link activated RTKs to several downstream pathways. Studying SH2 domain-containing proteins implicated in cancer signaling networks under given therapies can yield significant insight into the molecular basis of drug responses, thus having valuable clinical applications. Here, we demonstrate a microfluidic, peptide-microarray biochip technology (μPepArray™) for the label-free and multiplex detection of the endogenous SH2 domain proteins and signaling pathways from total protein lysate. The biochip contains 3968 reaction chambers, where the immobilized phosphopeptides serve as the molecular probes to capture present SH2 domain proteins. Using pancreatic cancer cells treated with epidermal growth factor receptor inhibitors (EGFRis), we identified the differentially expressed SH2 domain proteins such as SHP2, PLCG1, PI3K, and therefore the downstream phosphotyrosine-mediated signaling events occurred in response to treatments. Our findings revealed a signaling compensation between the EGFR/PI3K/Akt and mTORC2/PKCα/ERK pathways as a mechanism of EGFRi responses and potential resistance in BxPC-3 cells. We propose that the proteomic information provided by μPepArray™ technology could hold clinical significance by assisting in the cancer biomarker identification and guiding future treatment decisions. In the second approach of this dissertation, we utilize μPepArray™ technology for the high-throughput identification of histone SUMOylation. SUMOylation is a dynamic post-translational modification (PTM) process which covalently attaches a small ubiquitin-like modifier (SUMO) to a protein substrate. This modification alters protein functions and activities, ultimately affecting cellular responses and homeostasis. Histones play essential roles in epigenetic regulations. Different histone PTMs directly dictate chromatin structure and transcriptional activities. Identifying histone SUMOylation and specific lysine residues that are SUMOylated has been challenging due to limitations in technology. Using a customized library of lysine peptides derived from histone sequences, we have identified multiple histone SUMO modification sites as well as peptides that bind non-covalently to SUMO on the microarray chip. We propose that μPepArray™ technology offer a rapid screening assay to determine protein post-translational modifications, which will provide significant insights into PTM substrate specificity and their functions.
dc.description.departmentBiology and Biochemistry, Department of
dc.format.digitalOriginborn digital
dc.format.mimetypeapplication/pdf
dc.identifier.urihttps://hdl.handle.net/10657/5572
dc.language.isoeng
dc.rightsThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).
dc.subjectCell-signaling pathways
dc.subjectKinase activity
dc.subjectMicrofluidic peptide mircoarray
dc.subjectProteomics
dc.subjectSH2 domain
dc.titleProteomic Analysis of Post-Translational Modifications and Signaling Pathways in Pancreatic Cancer
dc.type.dcmiText
dc.type.genreThesis
local.embargo.lift2021-12-01
local.embargo.terms2021-12-01
thesis.degree.collegeCollege of Natural Sciences and Mathematics
thesis.degree.departmentBiology and Biochemistry, Department of
thesis.degree.disciplineBiochemistry
thesis.degree.grantorUniversity of Houston
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy

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