USP1 and pachyonychia congenita: Moreover, our EdU staining analysis showed that overexpression of HA-SIX1 or FLAG-USP1 by transfecting plasmids partially reversed the SNS-032-induced proliferation blockade in PC cells (Fig. 3J), indicating that the USP1-SIX1 axis is an important target of SNS-032 for inhibiting PC.