Nitroreductase-Mediated Release of Inhibitors of Lysine-Specific Demethylase 1 (LSD1) from Prodrugs in Transfected Acute Myeloid Leukaemia Cells

Lysine-specific demethylase 1 (LSD1) has evolved as a promising therapeutic target for cancer treatment, especially in acute myeloid leukaemia (AML). To approach the challenge of site-specific LSD1 inhibition, we developed an enzyme-prodrug system with the bacterial nitroreductase NfsB (NTR) that was expressed in the virally transfected AML cell line THP1-NTR+. The cellular activity of the NTR was proven with a new luminescent NTR probe. We synthesised a diverse set of nitroaromatic prodrugs that by design do not affect LSD1 and are reduced by the NTR to release an active LSD1 inhibitor. The 2-nitroimidazolyl prodrug (1f) of a potent LSD1 inhibitor emerged as one of the best prodrug candidates with a pronounced selectivity window between wild-type and transfected NTR+ cells. Our prodrugs are selectively activated and release the LSD1 inhibitor locally in turn blocking colony formation. This system may be applied in future targeting approaches to reach tissue- or organ-type-specific inhibition of LSD1.