Exploiting network-based drug repositioning to target metastasis in colorectal cancer: In-Silico prediction and in-vitro evidence

Abstract

Metastasis is a major challenge in colorectal cancer (CRC) treatment. The incidence of regional and distant stages has increased during the past decade and the 5-year survival of metastatic CRC patients is 20 %. Although there is a necessity to develop systematic treatment, the cost and time of novel drug discovery hinder this progress. Drug repositioning simplifies this process by accelerating regulatory processes in drug discovery. Here we used a systems biology approach to find key player genes in the metastasis. First, we found differentially expressed genes in metastatic tissue compared to primary tumors. Then, we constructed and analyzed the protein-protein interaction (PPI) network to find hub genes and subjected them to query in the DrugBank database. We found plasminogen (PLG) is the hub gene in the constructed PPI network and tranexamic acid (TXA) is its known inhibitor with clinically approved antifibrinolytic activity. Pathway enrichment analysis showed that PLG is involved in matrix remodeling, Platelet activation, and cell energy production through insulin-growth factor uptake in colorectal cancer cells which are important processes during metastasis. We further explored the CPTAC-COAD proteomics data and found that the PLG level is significantly higher in stage IV compared to stage I. Interestingly, we found that PLG is correlated with mutation rate. We then investigated the effect of TXA on SW480 cells' mobility and migration by scratch assay and transwell migration assay. Both assays indicated that TXA can significantly inhibit the cells’ migratory potential.