Data from A Novel Variant of Ileal Bile Acid Binding Protein Is Up-regulated through Nuclear Factor-κB Activation in Colorectal Adenocarcinoma

Abstract

<div>Abstract<p>Ileal bile acid binding protein (IBABP) is the only cytosolic protein known to bind and transport bile acids. Because IBABP is reportedly up-regulated in colorectal cancer, it has been suggested as a link between bile acids and the risk of colorectal cancer. However, in this study, we show that IBABP is not up-regulated. Rather, a novel transcript of the <i>IBABP</i> gene, which encodes an additional 49 NH<sub>2</sub>-terminal amino acid residues, is up-regulated in colorectal cancer (<i>P</i> < 0.001). The novel transcript, called IBABP-L, is also distinct from IBABP because its transcription is controlled by nuclear factor-κB (NF-κB) rather than by the farnesoid X receptor. Most significantly, IBABP-L is necessary for the survival of HCT116 colon cancer cells in the presence of physiologic levels of the secondary bile acid deoxycholate. Collectively, the studies point toward a unique bile acid response pathway involving NF-κB and IBABP-L that could be useful for diagnosis and could potentially be targeted for therapeutic benefit. [Cancer Res 2007;67(19):9039–46]</p></div>