Discovery of 1-(Azetidin-3-ylmethyl)-1 <i>H</i> -benzo[ <i>d</i> ]imidazole Derivatives as Efficient GSTP1 Inhibitors for Gastric Cancer Treatment via Warhead Removal Strategy

Gastric cancer is commonly diagnosed at advanced stages and frequently develops multidrug resistance (MDR). Clinical evidence highlights the overexpression of glutathione S-transferase pi 1 (GSTP1) in gastric cancer, which is closely associated with tumor progression and the development of MDR. However, highly potent and selective GSTP1 inhibitors remain scarce. Guided by our previously reported covalent DNA-encoded library (DEL) hit, a series of warhead-removed 1-(azetidin-3-ylmethyl)-1<i>H</i>-benzo[<i>d</i>]imidazole derivatives were obtained as noncovalent GSTP1 inhibitors. The most potent compound, <b>16n</b>, inhibited GSTP1 enzymatic activity with an IC₅₀ value of 0.79 ± 0.05 μM and demonstrated improved isoform selectivity. In human gastric cancer cells (AGS, HGC27, and NUGC-3), <b>16n</b> dose-dependently suppressed proliferation and increased intracellular reactive oxygen species levels while decreasing glutathione levels. Importantly, <b>16n</b> exhibited favorable systemic exposure and achieved 58% tumor growth inhibition with good tolerability in HGC27 xenograft mouse models. Collectively, <b>16n</b> represents a promising noncovalent GSTP1 inhibitor for the treatment of gastric cancer.