Logo image
Back
Discovery of non-canonical GNAS signaling in the growth of human pancreatic ductal organoids
Thesis

Discovery of non-canonical GNAS signaling in the growth of human pancreatic ductal organoids

Anagha Shringarpure
Master of Science (M.S.), Drexel University
Jun 2026
DOI:
https://doi.org/10.17918/00011479
pdf
Shringarpure_Anagha_20261.34 MB
PDF Embargoed Access, Embargo ends: 30 Jun 2028

Abstract

Biology Ductal organoids Intraductal papillary mucinous neoplasms Oncogenic GNAS PKA independent receptor tyrosine kinase Proteome array RNA-seq Pancreatic Cancer
Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease that can arise from macroscopic cystic precursor lesions such as intraductal papillary mucinous neoplasms (IPMNs). Although IPMNs are clinically detectable, factors determining their malignant potential remain unclear, leading to unnecessary surgeries and highlighting the need to understand mechanisms driving early IPMN progression. While KRAS mutations occur in IPMNs and other pancreatic precursor lesions, GNAS mutations are exclusive to IPMNs and arise early during lesion development. GNAS encodes the stimulatory G-protein alpha subunit (G[alpha]s), and activating R201C mutations constitutively activate G[alpha]s, increasing intracellular cAMP and canonical protein kinase A (PKA) signaling. Previous studies from our laboratory showed that oncogenic GNAS increases proliferation of human stem-cell-derived pancreatic ductal organoids through a PKA-independent mechanism. Therefore, we hypothesized that oncogenic GNAS promotes ductal cell proliferation through PKA-independent, kinase-associated signaling pathways. We used phospho-proteome array to profile 37 phospho-kinases in GNAS-expressing ductal organoids, with and without PKA inhibition. Oncogenic GNAS modulated phosphorylation of several kinases, including RSK1/2/3, GSK3[alpha]/[beta], HSP60, and WNK1, in the presence and absence of PKA signaling. Western blot validation showed that oncogenic GNAS reduced phosphorylation of RSK1 in the presence of PKA signaling, whereas RSK1 phosphorylation increased upon PKA inhibition, suggesting PKA-dependent modulation of RSK1 activity. We also observed PKA-independent increases in total GSK3[beta] and PLC-[gamma]1. Kinase enrichment analysis of bulk RNA-seq data showed upregulation of RSK1/2, GSK3[beta], and WNK1-associated signature genes. Together, these findings implicate RSK1/MAPK, GSK3[beta]/WNT, and WNK signaling in mutant GNAS-driven ductal growth and nominate PKA-independent targets for early IPMN interception.

Metrics

1 Record Views

Details

Logo image