Abstract 5758: Identification of MUC13 mediated molecular interactions in pancreatic cancer cells using immunoprecipitation combined with liquid chromatography mass spectrometry analysis

Abstract Background: MUC13, a recently identified oncoprotein, exhibits aberrant overexpression in pancreatic ductal adenocarcinoma (PDAC) and plays a crucial role in cancer progression. However, the precise molecular interactions mediated by MUC13 that contribute to PDAC progression and metastasis remain incompletely understood. To address this gap, we employed a comprehensive molecular interaction study using an integrated approach combining immunoprecipitation and Liquid Chromatography-Mass Spectrometry (IP-LCMS). This unique study revealed a novel cohort of MUC13-interacting proteins, potentially driving its oncogenic functions in PDAC. Methodology & Results: Five PDAC cell lines (CaPan2, HPAF-II, HPNE, Panc1, and MiaPaCa) were used for this analysis. Initial LCMS profiling showed high MUC13 expression in HPAFII, moderate levels in CaPan2, and minimal to undetectable expression in Panc1, MiaPaca, and HPNE (normal pancreatic cells). To validate these findings, ELISA, confocal microscopy, and immunoblotting complementary analyses were performed. immunoprecipitation (IP) was performed with MUC13-positive (MUC13+, HPAF-II) and MUC13-negative (MUC13̶, Panc1) cells with our in-house generated unique MUC13 monoclonal antibodies and appropriate IgG control antibodies. The immunoprecipitated proteins were processed for LCMS analysis. This IP-LCMS analysis demonstrated a robust channel signal for MUC13 in positive controls, whereas negative controls yielded minimal or non-significant signals. After normalization across experimental conditions, a total of 54 unique MUC13-interacting proteins were identified. Functional enrichment analysis highlighted the involvement of MUC13 associated interactome with various oncogenesis mechanisms, including central carbon metabolism, PD1/PD-L1 expression and immune checkpoint pathways, adherent junctions, senescence, cell cycle, apoptosis, viral carcinogenesis, diabetic cardiomyopathy etc. Conclusion: This study established a robust methodology (IP-LCMS) to identify MUC13 interactome, unveiling a cohort of molecular partners potentially mediating MUC13’s oncogenic functions in PDAC cells. These findings provide critical insights into MUC13-mediate oncogenic pathways, underscoring its role in cancer progression and therapeutic resistance. This work paves the new way for novel therapeutic strategies targeting precise MUC13-mediated molecular interactions. Key Word: MUC13, Pancreatic Cancer, IP-LCMS, Interactome, Functional Enrichment Citation Format: Anupam Dhasmana, Swati Dhasmana, Rajasekhar Baru, Abigail Gomez, Sheema Khan, Murali M. Yallapu, Subhash Chauhan. Identification of MUC13 mediated molecular interactions in pancreatic cancer cells using immunoprecipitation combined with liquid chromatography mass spectrometry analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5758.