Inverse Virtual Screening in Drug Repositioning: Detailed Investigation and Case Studies

Inverse virtual screening is a useful tool for drug repositioning or repurposing. The utility of this tool lies in the identification of potential targets for small-molecule ligands. With reference to drug repositioning , approved/existing small-molecule drugs can be processed by inverse virtual screening for the discovery of potential new molecular targets for such drugs. Both the ligand- and structure-based approaches can be used for the in silico screening. PharmMapper is a web-based tool for ligand-based inverse screening that employs pharmacophore mapping approach and identifies potential target candidates for small molecules. The present study demonstrates the usefulness of this approach for computational repositioning of approved/existing drugs. Here, query molecules belonging to protein kinase inhibitors, monoamine transporter inhibitors and G protein-coupled receptor antagonists were used. The results revealed potential novel molecular targets for the query molecules. Detailed literature search involving the query molecule-novel target pair led to interesting findings. The book chapter summarizes the interesting outcomes of the ligand-based inverse virtual screening.