Role of Gastrokine 2 in pancreatic cancer development

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Abstract Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest adult cancers with a 5-year survival rate of only 11% and is one of the top five leading causes of cancer-related deaths for men and women in the United States. These dire statistics underscore the need for a better understanding of the mechanisms that promote pancreatic cancer initiation and progression. Recent studies have begun to show that metaplastic epithelial differentiation in pancreatic cancer can significantly impact disease progression. Our preliminary data from ongoing studies investigating the role of cytokines IL-12/IL-23 in pancreatic cancer cell differentiation showed that gain of aggressive epithelial to mesenchymal-like phenotype is associated with the concurrent loss of gastric lineage genes, including Gastrokine 2 (Gkn2). Gkn2 is abundantly expressed by normal stomach epithelial cells, plays an anti-inflammatory role in gastric epithelial homeostasis. Recently, Gkn2 and its family member Gkn1 have been shown to be de novo upregulated in metaplastic epithelial cells in pancreatic cancer. However, the functional roles of gastrokines in pancreatic tumorigenesis remain unclear. The goals of this proposal are to elucidate the kinetics, cellular source, and driver(s) of de novo Gkn2 expression in pancreatic neoplasia, as well as determine the functional role of Gkn2 in pancreatic cancer development. To achieve these goals, in Aim 1, we will determine the expression pattern and cellular identity of Gkn2-positive cells, as well as understand how oncogenic Kras and/or Src signaling may contribute to the expression of Gkn2 in pancreatic epithelial cells. In Aim 2, we will investigate the functional role of Gkn2 in pancreatic tumor growth, tumor cell differentiation, and invasion. Specifically, we will utilize reversible Gkn2 knockdown systems to determine its contribution to the growth and differentiation of Kras-transformed epithelial cells in pancreatic cancer. Our proposed research will utilize state-of-the art models to provide an understanding of how a gastric identity gene program emerges early in transformed pancreatic epithelium and acts as a potential impediment to the aggressive progression of cancer.