Metabolic and proteomic profiling in cholangiocarcinoma

Background: Cholangiocarcinoma (CCA) has a very poor prognosis and the aetiology is not clearly understood. Analytical biochemical techniques may provide insights into pathogenesis and cellular signalling pathways as well as identifying novel diagnostic and prognostic biomarkers of disease. Particularly relevant are mass spectrometry (MS)-based quantitative proteomics of tissue and magnetic resonance spectroscopy (MRS) of bile. Methods: MS: 28-80 /-lg of microsomal protein from paired CCA and normal adjacent tissue from two patients were reduced, alkylated, trypsin digested and subsequently labelled with isobaric tag reagents, combined and separated by two-dimensional high-performance liquid chromatography and analysed by tandem mass spectrometry. MRS: In vitro proton MR data were acquired from bile from five CCA cases and compared to disease control bile from benign biliary disease (seven gallstones, eight sphincter of Oddi dysfunction, and five primary sclerosing cholangitis [PSC]). Results: MS: Proteins over-expressed in both CCA tissues included galectin-3-binding protein precursor, proteasome subunit beta type 1 precursor and type 6 precursor. Proteins involved in bile acid synthesis (sterol 12-hydroxylase, CYP8B1) conjugation (bile acyl CoA synthetase, BACS) and glucuronidation (UDP-glucuronsyltransferases precursor proteins, UGT2B4, UGT2827) were downregulated in CCA tissue, while the bile acid transporter, bile salt export pump (BSEP), was over-expressed. MRS: Taurine-and glycine-conjugated bile acids were elevated in bile in patients with CCA when compared to bile from patients with PSG (p=O.016, p=0.008). Biliary phosphatidylcholine levels were reduced in patients with CGA when compared to those with gallstones (p=0.030). Conclusions: The proteomic and MRS data suggest altered bile acid metabolism plays an important role in CGA aetiopathogenesis.EThOS - Electronic Theses Online ServiceGBUnited Kingdo