Identification of Keratinocyte Cytoprotectants against Toxicity by the Multikinase Inhibitor Sorafenib Using Drug Repositioning

Abstract

Hand-foot skin reaction (HFSR) is the most common adverse event of multikinase inhibitors (MKI), such as sorafenib. Although HFSR is not life-threatening, severe cases impair quality of life because of pain and reduced activities of daily living. However, the pathological mechanisms of HFSR have not yet been elucidated in detail, and there is currently no effective treatment. We aimed to identify keratinocyte cytoprotectants against sorafenib toxicity.The screening of cytoprotectants against sorafenib toxicity was performed using cultured normal human epidermal keratinocytes (NHEKs) or a reconstructed human epidermis (RHE) model and off-patent approved drugs in the Prestwick Chemical library. Among 1273 drugs in the chemical library, 8 dose-dependently increased cell viability by more than 200% in the presence of sorafenib. In the presence of sorafenib, the number of proliferating cell nuclear antigen- positive cell was significantly higher in clofazimine-, cyclosporin A-, and itraconazole-treated RHE models than in sorafenib-treated models. And, candidate drugs suppressed sorafenib-induced apoptosis in NHEKs. In addition, clofazimine, itraconazole and pyrvinium pamoate significantly recovered the phosphorylation of ERK1/2 in the presence of sorafenib. Collectively, hit drugs promoted cell viability and normalized keratinocyte proliferation in the presence of sorafenib. These candidate drugs have potential as treatments for MKI-induced HFSR.