A Metabolomics-based strategy to assess drug hepatotoxicity and uncover the mechanisms of hepatotoxicity involved

Toxicity studies, among them hepatotoxicity, are key throughout preclinical stages of drug development to minimize undesired toxic effects that might later appear during the clinical use of a new drug. Here, we envisage an innovative strategy to identify potential hepatotoxic drugs and uncover the mechanisms of toxicity. This strategy was based on the analysis of metabolome changes induced by hepatotoxic and non-hepatotoxic compounds in HepG2 cells, assessed by untargeted mass spectrometry. As a training set we used 25 hepatotoxic and 4 non-hepatotoxic compounds and incubated HepG2 cells for 24 h at a IC10 and IC50 concentration to identify metabolomic toxicity biomarkers and elaborate prediction models accounting for global hepatotoxicity and toxicity mechanisms. Thereafter, a second set of 69 chemicals with known predominant mechanisms of toxicity and 18 non-hepatotoxic compounds were analysed at 1, 10, 100 and 1000 µM concentrations from which, based on the magnitude of the alterations caused as compared with non-toxic compounds, we defined a “toxicity index” for each compound. In addition we extracted from the metabolome data the characteristic signatures for each mechanism of toxicity.