Cholangiocarcinoma (CCA) is a form of hepatobiliary cancer with an abysmal prognosis.Despite advances in our understanding of CCA pathophysiology and its genomic landscape, targeted therapies have not yet made a significant impact on its clinical management. The low response rates of targeted therapies in CCA suggests that patient heterogeneity contributes to poor clinical outcome. Here we used mass spectrometry-based phosphoproteomics and computational methods to identify patient-specific drug targets in patient tumors and CCA-derived cell lines. We analyzed 13 primary CCA patient tumors with matched non-malignant tissue and 7 different CCA cell lines, leading to the identification and quantification of >13,000 phosphorylation sites. The phosphoproteomes of CCA cell lines and patient tumors were significantly correlated. MEK1, KIT, ERK1/2, and several cyclindependent kinases were among the protein kinases most frequently showing increased activity in CCA relative to non-malignant tissue. Application of the Drug Ranking Using Machine Learning (DRUML) algorithm selected inhibitors of HDAC (belinostat and CAY10603) and PI3K pathway members as high-ranking therapies to use in primary CCA.The accuracy of the computational drug rankings based on predicted responses was confirmed in cell line models of CCA. Together, this study uncovers frequently activated biochemical pathways in CCA and provides a proof of concept for the application of computational methodology to rank drugs based on efficacy in individual patients.
STATEMENT OF SIGNIFICANCEPhosphoproteomic and computational analyses identify patient-specific drug targets in cholangiocarcinoma, supporting the potential of a machine learning method to predict personalized therapies.Research.