Abstract 3827: Chronic alcohol consumption promotes pancreatic cancer liver metastasis in mice through PAD4-mediated pre-metastatic niche formation
Authors: Jieun Kim, So Yeon Kim, Justyna Fert-Bober, Syed Kazmi, Stephen J. Pandol, Ekihiro Seki
Journal: Cancer Research (2025)

Liver metastasis is a critical determinant of prognosis for patients with pancreatic ductal adenocarcinoma (PDAC). The liver microenvironment, shaped by underlying liver diseases such as alcohol-associated liver disease (ALD), significantly influences the progression of liver metastasis. However, the molecular mechanisms underlying liver metastasis in the context of ALD remain poorly understood. Steatosis and neutrophil infiltration, common features of ALD, are known to alter the hepatic microenvironment. Peptidylarginine deiminase 4 (PAD4), an enzyme primarily expressed in neutrophils, catalyzes citrullination, a post-translational modification that impacts protein structure and function. Here, we investigated the impact of chronic alcohol consumption on liver metastasis progression using animal models and explored the role of PAD4 in this process. Female C57BL/6 wild-type and neutrophil-specific PAD4-deleted mice were fed either an isocaloric diet or 5% ethanol Lieber-DeCarli diet for 6 weeks. Liver metastases were induced via intrasplenic injection of Pan02 mouse PDAC cells, followed by two additional weeks of diet. Neutrophil-specific PAD4-deleted mice were generated by crossing PAD4-floxed mice with MRP8-Cre mice. JBI-1044, a novel PAD4 inhibitor developed by Jubilant Therapeutics Inc., was administered via orally twice daily. Chronic alcohol consumption exacerbated metastatic tumor growth, correlating with increased PAD4 expression, neutrophil infiltration, and collagen deposition. Our single-cell RNA sequencing confirmed that tumor-associated neutrophils are the primary source of PAD4. Immunohistochemical staining for peptidyl-citrulline revealed its accumulation within metastatic tumors and enhanced citrullination in the livers of alcohol-fed mice compared to controls. Our proteomics analysis identified a significant increase in PAD4-mediated citrullination in the metastatic tumors of alcohol-fed mice, targeting vimentin and extracellular matrix proteins. Chronic alcohol-fed mice showed reduced survival. In contrast, PAD4 deletion in neutrophils suppressed metastatic tumor growth in the livers of alcohol-fed mice, accompanied by reduced neutrophil infiltration, collagen deposition, and citrullination. Treatment with JBI-1044 significantly improved survival and decreased the tumor growth in alcohol-fed mice by reducing neutrophil infiltration and collagen deposition. In conclusion, PAD4 plays a pivotal role in pre-metastatic niche formation and remodeling of the liver tumor microenvironment in PDAC liver metastasis associated with ALD. By regulating neutrophil activity and collagen deposition, PAD4 contributes to the progression of liver metastases. Selective inhibition of PAD4 with JBI-1044 represents a promising therapeutic strategy for managing PDAC liver metastasis in the context of ALD. Citation Format: Jieun Kim, So Yeon Kim, Justyna Fert-Bober, Syed Kazmi, Stephen J. Pandol, Ekihiro Seki. Chronic alcohol consumption promotes pancreatic cancer liver metastasis in mice through PAD4-mediated pre-metastatic niche formation [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 3827.