Reactive metabolite of gefitinib activates inflammasomes: Implications for gefitinib-induced idiosyncratic reaction

Abstract

The epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) have been approved for non-small cell lung cancer. Although EGFR TKIs are less toxic than traditional cytotox-ic therapies, they cause many severe idiosyncratic drug reactions. Reactive metabolites can cause cellular damage with the release of danger-associated molecular patterns (DAMPs), which is thought to be involved in immune activation. Inflammasomes can be activated by DAMPs, and this may be a common mechanism by which DAMPs initiate an immune response. We tested the ability of afatinib, dacomitinib, erlotinib, gefitinib, and osimertinib to induce the release of DAMPs that activate inflammasomes. Human hepatocarcinoma functional liver cell-4 (FLC-4) cells were used for bioactivation of drugs, and the detec-tion of inflammasome activation was performed with the human macrophage cell line, THP-1 cells. Gefit-inib is known to be oxidized to a reactive iminoquinone metabolite. We found that the supernatant from the incubation of gefitinib with FLC-4 cells for 7 days led to increased caspase-1 activity and production of IL-1ß by THP-1 cells. In the supernatant of FLC-4 cells with gefitinib, the heat shock protein (HSP) 40, 70 and 90 were significantly increased. In addition, activated THP-1 cells secreted high mobil-ity group box 1 (HMGB1) protein. These results support the hypothesis that the reactive iminoquinone metabolite can cause the release of DAMPs from hepatocytes, which in turn, can activate inflammasomes. Inflammasome activation may be an important step in the activation of the immune system by gefitinib, which in some patients, can cause immune-related adverse events.