Abstract 2174: Differential gene overexpression in highly malignant erbB2/neu transformed rat BDE1 cholangiocytes versus less aggressive spontaneously transformed BDE1 cholangiocytes

Abstract

Abstract Intrahepatic cholangiocarcinoma is a highly malignant primary hepatobiliary cancer often presenting as advanced disease with a dismal prognosis. Despite advances, the molecular pathogenesis of cholangiocarcinoma progression is still poorly understood. Previously, we described a unique “patient-like” animal model of intrahepatic cholangiocarcinoma based on bile duct inoculation of highly malignant erbB2/neu transformed rat BDE1 cholangiocytes (BDEneu cells) compared to less malignant spontaneously transformed BDE1 cholangiocytes (BDEsp cells) into the livers of syngeneic rats (Sirica, A.E., et al. 2008; 47:1178-1190). The aim of this study was to use gene expression microarray analysis, validated with quantitative real-time RT-PCR, to provide a profile of significantly overexpressed gene targets in highly tumorigenic BDEneu cells and resultant tumors compared to less malignant BDEsp cells and tumors. Our microarray analysis identified 4,711 probe sets that were significantly (q < 0.05) different between cultured ErbB2-overexpressing BDEneu cells compared to BDEsp cells and 3,090 probe sets that were significantly different between BDEneu tumors and BDEsp tumors. Among the genes identified as being most abundantly overexpressed in BDEneu cells compared to BDEsp cells included: radixin (57-fold), Sox17 (47-fold), metallothionein 2A (40-fold), insulin-like growth factor binding protein-7 (36-fold), keratin 20 (23-fold), fibronectin 1 (25-fold), transmembrane mucin1 (20-fold), cancer susceptibility candidate 4 (18-fold), tropomyosin 2 (17-fold), bone morphogenetic protein-7 (8-fold), ErbB2 (5-fold), and sphingosine kinase 1 (4-fold). Nine of these twelve abundantly overexpressed genes were also determined to be significantly overexpressed in orthotopic BDEneu liver tumors compared to BDEsp tumors, indicatative of being inherent indicators of transformed BDE cholangiocytes of increased malignant potential. In comparison, the extracellular matrix genes, periostin and tenascin, were found to be overexpressed by >600-fold and >100-fold, respectively, in the BDE liver tumors when compared to the cultured BDE cell lines, supporting their tumor stromal origin. Quantitative real-time RT-PCR analysis of BDEneu tumors further demonstrated a strong positive correlation between increased levels of mRNA transcripts for selected genes (i.e., Sox 17, keratin 20, sphingosine kinase 1, and amphiregulin) and progressively increased liver tumor size. Interestingly, amphiregulin mRNA, which was determined to be underexpressed in cultured BDEneu cells compared to BDEsp cells, was significantly increased in the BDEneu tumors over that expressed in the BDEsp tumors, and appeared to correlate with progression in BDEneu cholangiocarcinoma. (Supported by R01 CA 39225 and R01 CA 83650 to A.E.S). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2174.