Abstract 41: Identification of CXCL5/ENA-78 regulating the interaction of cholangiocarcinoma and cancer-associated fibroblasts

Abstract

Abstract Background and Aims: Tumor-stromal interaction has been recognized to be essential for understanding tumor development. Cholangiocarcinoma shows very poor prognosis and have fibrous tumor stroma. Hepatic stellate cells are well-known to have a major role in hepatic fibrogenesis. Therefore, we have focused on the interaction of cholangiocarcinoma and hepatic stellate cells and reported their positive interaction (Ann Surg Oncol 2009, 2011). The aim of this study is to identify the key protein which is important for the interaction of cholangiocarcinoma cells and hepatic stellate cells and examine its functional role in tumor progression. Methods: Using co-culture model and proteomic analysis, we analyzed the secreted factors which were considered to be important for their interaction. The functional role of CXCL5 was examined in vitro and clinical significance was validated using human intrahepatic carcinoma samples by immunohistochemistry. Results: Using SELDI-TOF-MS and qTOF-MS/MS analysis, we identified CXCL5 which was remarkably increased when they were co-cultured. CXCL5 which was mainly produced by cholangiocarcinoma cell lines (HuCCT1 and RBE) promoted the invasion, and migration of them in the autocrine fashion. These effects were significantly decreased by inhibition of CXCR2 which was a receptor of CXCL5. IL1β was found to up-regulate in hepatic stellate cells when they were co-cultured by cytokine array analysis, we also found that IL1β accelerated the production of CXCL5 in cholangiocarcinoma cells. In human intrahepatic cholangiocarcinoma, immunohistochemical study showed that there was a significant correlation between stromal myofibroblasts and CXCL5 produced by cholangiocarcinoma cells. Since CXCL5 is identified as epithelial neutrophil activating factor-78 (ENA-78), we researched the presence of CD66b positive immune cells which have been recently reported to be tumor-associated neutrophils. CD66b positive immune cells are more abundant in CXCL5 high expression group. In addition, high CXCL5 expression group showed worse survival than low expression group. Conclusion: We conclude that CXCL5 is important for the interaction of cholangiocarcinoma and stromal myofibroblasts and that the strategies to inhibit tumor-stromal cell interactions may be beneficial in cholangiocarcinoma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 41. doi:1538-7445.AM2012-41