Abstract 5358: IL-4/IL-13 induce Duox2/DuoxA2 expression and reactive oxygen production in human pancreatic and colon cancer cells

Abstract

Abstract NADPH oxidase (NOX)-derived reactive oxygen species (ROS) contribute significantly to inflammation-associated carcinogenesis. Expression of dual oxidase 2 (Duox2), one of seven members of the NOX gene family, is up-regulated in inflammatory bowel disease, chronic pancreatitis, and in many human malignancies including carcinomas of the prostate, lung, and breast. Previously, we demonstrated that Stat1 and/or NF-κB play a critical role in modulating the enhanced expression of Duox2, and its cognate maturation factor DuoxA2, by IFN-γ and lipopolysaccharide in human pancreatic cancer cells. This cytokine-mediated increase in Duox2 expression is responsible for a consequent significant increase in tumor cell H2O2 production and DNA damage. Using Caco2 and T84 human colon cancer lines, and BxPC-3 pancreatic cancer cells, we now report that two other pro-inflammatory cytokines, IL-4 and IL-13, also strongly induce Duox2/DuoxA2 RNA and protein expression (>5-10-fold after 24h treatment with 50 ng/ml cytokine). In the BxPC-3 line, IL-4 exposure activates the Stat6 signaling pathway, enhances expression of Duox2/DuoxA2 in a time- and concentration-dependent manner, and leads to a significant increase in the generation of extracellular H2O2. The transcription and translation inhibitors actinomycin D and cyclohexamide both individually suppress IL-4-induced Duox2 expression, suggesting that IL-4-mediated Duox2 up-regulation is transcriptionally regulated, but that new protein synthesis is also necessary. We found that Stat6 is essential for IL-4-induced Duox2 expression because silencing Stat6 with Stat6-specific siRNA significantly attenuates IL-4-induced Duox2 RNA and protein levels in BxPC-3 cells. To evaluate the potential role of Duox2 in inflammation-associated human cancers further, immunohistochemical studies were performed to semi-quantitatively examine Duox expression using human pancreatic and colon cancer tissue arrays. We found that a majority of samples of pancreatic intra-epithelial neoplasia and frank pancreatic cancer demonstrated high-level expression of Duox , often in association with inflammatory cell infiltrates; high-level Duox expression was also found in most colorectal cancer samples. These studies, in concert with our previous experiments, strongly suggest that ROS, produced as a consequence of cytokine-induced Duox up-regulation, may be associated with the development of inflammation-related gastrointestinal malignancies. Note: This abstract was not presented at the meeting. Citation Format: Yongzhong Wu, James H. Doroshow. IL-4/IL-13 induce Duox2/DuoxA2 expression and reactive oxygen production in human pancreatic and colon cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5358. doi:10.1158/1538-7445.AM2014-5358