Fig. 1: Reduction of OBI-3424 by AKR1C3 in the presence of NADPH to produce the cytotoxic agent OBI-2660.

In the presence of NADPH, reduction of OBI-3424 is mediated by AKR1C3 to release the cytotoxic moiety OBI-2660, which is an aziridine bis-alkylating agent, leading to crosslinking of DNA at the N7 (or O6) position of guanine and subsequent cell death. AKR1C3 aldo-keto reductase family 1 member C3.