Despite recent advances in bioinformatics, systems biology, and machine learning, the accurate prediction of drug properties remains an open problem. Indeed, because the biological environment is a complex system, the traditional approach -based on knowledge about the chemical structures -cannot fully explain the nature of interactions between drugs and biological targets. Consequently, in this paper, we propose an unsupervised machine learning approach that uses the information we know about drug-target interactions to infer drug properties. To this end, we define drug similarity based on drug-target interactions and build a weighted Drug-Drug Similarity Network according to the drug-drug similarity relationships. Using an energy-model network layout, we generate drug communities that are associated with specific, dominant drug properties. However, 13.59% of the drugs in these communities seem not to match the dominant pharmacologic property. Thus, we consider them as drug repurposing hints. The resources required to test all these repurposing hints are considerable. Therefore we introduce a mechanism of prioritization based on the betweenness/degree node centrality. By using betweenness/degree as an indicator of drug repurposing potential, we identify the drug Meprobamate as a possible antifungal. Finally, we use a robust test procedure, based on molecular docking, to further confirm the repurposing of Meprobamate.
Author summaryWe address the salient problem of drug repurposing by using an unsupervised machine learning technique (i.e., clustering) on a drug network (i.e., nodes represent drugs and links represent relationships between two drugs). To this end, we build a drug-drug similarity network (DDSN) using information about drug-target interactions, then March 7, 2020 1/22 perform network clustering and associate the clusters with drug properties. To validate our DDSN clustering approach, we use an old drug database to render the cluster-property pairs and then verify them with the information from the latest database. Indeed, the properties uncovered with our DDSN clustering are confirmed for 86.41% of the drugs; for the remaining 13.59%, we assume that the associated property is not fortuitous, thus representing repositioning hints. As the number of repositioning hints is considerable, we prioritize them with a new approach, based on the node betweenness/degree ratio. The prioritization of repositioning hints renders the repurposing of Meprobamate (known as a hypnotic and sedative drug) as an antifungal drug. We also test and confirm the robustness of our hypothesis using an original, formal procedure based on computer-simulated molecular docking. 14 development (R&D) time and costs, as well as medication risks, which makes it 15particularly efficient for developing orphan/rare disease therapies [8,9].
16The recent developments confirm computational methods as powerful tools for drug 17 repositioning:
18• The trivialization/spread of omics analytical approaches have generated significant 19March 7, 2020...