Abstract C070: Keratin 17 and GATA6 correlate with diffusely infiltrative versus gland-forming components of PDAC: Uncovering the transitional state in pancreatic ductal adenocarcinoma

Abstract Purpose: Optimization of pancreatic ductal adenocarcinoma (PDAC) patient survival will depend on advancing our understanding of the mechanisms governing tumor cell plasticity and effectively mitigating their invasive and metastatic capabilities. This study aims to investigate the correlation of cancer biomarkers crucial to these processes by integrating molecular signatures with histopathological characteristics using single-cell RNA sequencing (scRNA-seq) and multiplexed IHC/IF. Methods: Single-cell RNA sequencing (scRNA-seq) data from a comprehensive dataset of over 53,000 PDAC cells and validation of lead targets through 14-plex immunofluorescence, using a customized MICS platform (Miltenyi Biotec) and dual color IHC were employed to assess protein expression of defining biomarkers of basal and classical subtypes of PDAC including Keratin 17 (K17) and GATA6. Results: scRNAseq analysis revealed distinct patterns of K17 and GATA6 expression, highlighting intratumoral heterogeneity among PDAC tumors. Specifically, populations of cells expressing K17+/GATA6+ and K17+/GATA6- exhibited significant enrichment in pathways associated with invasion and cell migration, including PI3K/Akt/mTOR, TGF-β, and epithelial-mesenchymal transition (EMT) signaling. Conversely, GATA6-/K17- cells demonstrated enrichment in biosynthetic and metabolic pathways that govern cell cycle regulation. Additionally, mIF data assessment revealed correlations between histomorphological patterns and dynamic shifts in K17 and GATA6 expression within PDAC tumors. Diffusely infiltrative tumor cells (DITCs) uniformly expressed K17, contrasting with the gland-forming components (GFCs) of PDAC, which showed enrichment in GATA6 and sporadic expression of K17. E-cadherin, a key adhesion marker, exhibited the highest expression levels in the glandular and solid components of PDAC, underscoring their epithelial characteristics. Conversely, vimentin, a marker typically associated with epithelial-to-mesenchymal transition (EMT), was significantly expressed in DITCs, suggesting a mesenchymal-like phenotype in these infiltrative cells. Dual color IHC further validated these findings, reinforcing the correlation between morphologic plasticity and the expression patterns of K17 and GATA6, emphasizing their potential to distinguish distinct tumor cell populations within PDAC. Conclusions: These insights suggest that the interaction between these markers may indicate a distinct biological state characterized by altered cellular metabolism and potentially different therapeutic vulnerabilities. The robust association between K17 expression and diffusely infiltrative tumor cells underscores its potential as a marker for the most aggressive forms of this disease. Our results highlight the heterogeneous nature of PDAC and emphasize the critical importance of understanding these molecular distinctions in histopathological contexts to develop targeted therapies aimed at improving patient survival. Citation Format: Lyanne A Delgado- Coka, Brian Nelson, Michael Horowitz, Shayan Sarkar, Natalia Marchenko, Scott Powers, Luisa F Escobar-Hoyos, Kenneth Shroyer. Keratin 17 and GATA6 correlate with diffusely infiltrative versus gland-forming components of PDAC: Uncovering the transitional state in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C070.