Lysine-specific demethylase inhibitor (1C) (LSD inhibitor (1C)) is an inhibitor of LSD1, a repressive demethylase selective for histone H3 lysine 4 (H3K4).1,2LSD inhibitor (1C) inhibits LSD1 activity by 85.9% when used at a concentration of 10 μM.1It increases the level of H3K4 methylation, including H3K4me1 and H3K4me2 but not H3K9me2 levels, in HCT116 human colon carcinoma cells.2LSD inhibitor (1C) also induces re-expression of the Wnt signaling pathway proteins secreted frizzle-related protein 1 (SFRP1), SFRP4, and SFRP5, as well as the transcription factor GATA5, which are aberrantly silenced in HCT116 cells.