Abstract 6578: Heat shock protein inhibitors suppress cytokine-induced DUOX2 mRNA and protein expression in human pancreatic cancer cells in a JAK, STAT dependent manner

Abstract Dual oxidase 2 (DUOX2), one of the seven NADPH oxidases family members, plays a critical role in both host defense and chronic inflammation-associated cancer in the gastrointestinal system. In vitro, pro-inflammatory cytokines, such as IFN- y, IFNα/β, IL-4 and IL-17A, enhance DUOX2/DUOXA2 expression through activation of STATs and NF-kB signaling pathway proteins; in vivo, DUOX protein and mRNA levels are substantially upregulated in chronic pancreatitis, pre-malignant pancreatic intraepithelial neoplasms and the early stages of pancreatic cancer patients compared to histologically normal pancreatic tissues. In pancreatic adenocarcinoma, increased DUOX2 expression is adversely correlated with overall patient survival. Heat-Shock Protein 90 (Hsp90), an important molecular chaperone involved in tumorigenesis, invasion and metastasis of cancer cells, is critical in folding, maturation and stability of many oncogenic client proteins, including kinases such as AKT and JAK1/2, and transcription factors, such as STAT3 and HIF-1α. Several STAT family members, along with Hsp90, are overexpressed in human pancreatic carcinomas. Using a panel of human pancreatic cancer cell lines (BxPC-3, AsPC-1 and CFPAC-1), we found that two different Hsp90 inhibitors, Tanespimycin (17-AAG) and Ganetespib (STA-9090), inhibit JAK1 and JAK2 kinases, blocking cytokine-induced, JAK-regulated STAT phosphorylation. Additionally, these Hsp90 inhibitors suppress cytokine-induced DUOX2, VEGF-A, MMP-7 and PD-L1 expression in human pancreatic cancer cell lines with varying sensitivity. Furthermore, the JAK1/2 inhibitor Ruxolitinib inhibits IL-4 induced and JAK-mediated STAT6 phosphorylation, and DUOX2 mRNA and protein expression in BxPC-3 cells. Similar results were observed with JAK1, STAT1, 2 and STAT6 specific siRNA knockdown. However, simultaneous knockdown of both isoforms of Hsp90, Hsp90α and Hsp90β, with specific siRNA did not inhibit JAK1 activity, cytokine-induced DUOX2 mRNA or protein expression. Either remaining Hsp90 protein or other isoforms of Hsp90 in cells may compensate decreased Hsp90 function after siRNA knockdown. Our data suggests that Hsp90 inhibitors, through blocking the cytokine-activated JAK-STATs oncogenic signaling pathway and their downstream genes such as DUOX2, VEGF-A, MMP-7 and PD-L1expression, may be a valuable therapeutic approach for inflammation-associated pancreatic cancer. Citation Format: Yongzhong Wu, David J. Mallick, Allan Di, Smitha Antony, Jennifer Meitzler, Mariam M. Konaté, Becky Diebold, Krishnendu Roy, James H. Doroshow. Heat shock protein inhibitors suppress cytokine-induced DUOX2 mRNA and protein expression in human pancreatic cancer cells in a JAK, STAT dependent manner abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6578.