Mechanisms of survival signaling in biliary epithelia

DESCRIPTION (provided by applicant): Our overall objectives are to define and understand the cellular mechanisms responsible for tumor development and progression in biliary epithelia. Chronic biliary tract inflammation predisposes to cholangiocarcinoma formation. Our long term objectives are to understand the mechanisms by which inflammatory mediators contribute to the development and progression of cholangiocarcinoma. We have focused on understanding the mechanisms by which aberrant cellular responses to Interleukin-6 contribute to cholangiocarcinoma growth and response to therapy. We have shown that: (i) IL-6 modulates expression of non-coding RNA (ncRNA) genes such as microRNAs (miRNA) and transcribed ultraconserved regions (UCR); (ii) selected ncRNA genes are aberrantly expressed in human cholangiocarcinoma and can modulate the response to therapeutic interventions; (iii) IL-6 modulates DNMT-1 and cancer-associated gene expression in a miRNA dependent manner; (iv) cholangiocytes release nanoparticles that contain ncRNA; and (v) computational bioinformatics analysis of genomic profiles associated with IL-6 expression can identify novel therapeutics. Based on these striking and extensive preliminary data, we propose the CENTRAL HYPOTHESIS that de-regulated expression of IL-6 during biliary tract inflammation leads to altered intracellular signaling and modified expression of ncRNA resulting in aberrant gene expression which enhances tumorigenesis and growth in biliary epithelia. We will now use current and complementary molecular, biochemical and cell biological approaches to ascertain how IL-6 regulates these unexplored pathways of regulation of gene expression. Our proposal has four SPECIFIC AIMS. FIRST, we will directly test the hypothesis that IL-6 modulates methylation dependent expression of genes involved in cholangiocarcinogenesis by altered expression of miRNA. SECOND, we will test the hypothesis that expression of miRNA can be modulated by UCR. NEXT, we will evaluate ncRNA as intercellular signaling intermediates capable of effecting cellular changes. FINALLY, we will test the hypothesis that IL-6 dependent ncRNA expression can be targeted for treatment of cholangiocarcinoma. The innovative aspects of this proposal include: new concepts regarding the inflammation-cancer axis, regulation and function of ncRNA genes, and mechanisms of intercellular communication; new in vitro approaches to elucidating RNA gene function and biological roles and test of new hypotheses regarding regulation of gene expression and their functional impact. Our results will yield new mechanistic insights into cholangiocyte responses to environmental changes, identify the role and functions of novel RNA genes in the molecular pathogenesis of cholangiocarcinoma and identify novel therapeutic strategies for these cancers.