Abstract
BackgroundDetection of cholangiocarcinoma (CCA) remains a diagnostic challenge. We established diagnostic peptide biomarkers in bile and urine based on capillary electrophoresis coupled to mass spectrometry (CE-MS) to detect both local and systemic changes during CCA progression. In a prospective cohort study we recently demonstrated that combined bile and urine proteome analysis could further improve diagnostic accuracy of CCA diagnosis in patients with unknown biliary strictures. As a continuation of these investigations, the aim of the present study was to investigate the pathophysiological mechanisms behind the molecular determinants reflected by bile and urine peptide biomarkers.MethodsProtease mapping and gene ontology cluster analysis were performed for the previously defined CE-MS based biomarkers in bile and urine. For that purpose, bile and urine peptide profiles (from samples both collected at the date of endoscopy) were investigated from a representative cohort of patients with benign (n = 76) or CCA-associated (n = 52) biliary strictures (verified during clinical follow-up). This was supplemented with a literature search for the association of the individual biomarkers included in the proteomic patterns with CCA or cancer progression.ResultsFor most of the peptide markers, association to CCA has been described in literature. Protease mapping revealed ADAMTS4 activity in cleavage of both bile and urine CCA peptide biomarkers. Furthermore, increased chymase activity in bile points to mast cell activation at the tumor site. Gene ontology cluster analysis indicates cellular response to chemical stimuli and stress response as local and extracellular matrix reorganization by tissue destruction and repair as systemic events. The analysis further supports that the mapped proteases are drivers of local and systemic events.ConclusionsThe study supports connection of the CCA-associated peptide biomarkers to the molecular pathophysiology and indicates an involvement in epithelial-to-mesenchymal transition, generation of cancer-associated fibroblasts and activation of residual immune cells. Proteases, extracellular matrix components, inflammatory cytokines, proangiogenic, growth and vasoactive factors released from the tumor microenvironment are drivers of systemic early events during CCA progression.
Highlights
Detection of cholangiocarcinoma (CCA) remains a diagnostic challenge
CCA diagnosis based on bile and urine proteome analysis Based on the proteome analysis, a patient sample is assigned to the case or control group according to the degree of similarity in its individual marker profile to the prototypical CCA peptide marker signature with the later defined during the establishment of the peptide marker model
By comparing peptide levels with publicly available tissue transcriptomics data sets, we identified increased expression of 14–3-3 ζ/δ protein (YWHAZ), Cytoplasmic actin 1 (ACTB), F-actin-capping protein subunit β (CAPZB), SPP1 and the collagen chains Collagen chain α-2(I) (COL1A2), Collagen chain α-1(XVII) (COL17A1), Collagen chain α1(III) (COL3A1) and Collagen chain α-2(V) (COL5A2) in the CCA tumor both in the NCBI GEO and in the Whole Cancer Genome data sets and in agreement with our peptide profiles
Summary
Detection of cholangiocarcinoma (CCA) remains a diagnostic challenge. We established diagnostic peptide biomarkers in bile and urine based on capillary electrophoresis coupled to mass spectrometry (CE-MS) to detect both local and systemic changes during CCA progression. Due to poor response to chemotherapy, early surgery is currently the only curative treatment option available. It is associated with 5–10% mortality rates and even with margin-free resection, 5-year survival rates only reach 20–40%. In 50–95% of cases, CCA is detected at a stage when it is too late for resection. In this case, prognosis is poor with median survival being 5 months. In 2018, CCA accounted for 165,087 of deaths worldwide according to the GLOBOCAN database (released in September 2018)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call