Design, synthesis, and biological evaluation of indole-based inhibitors targeting KRASG12D-mutant cancers

KRAS, the most frequently mutated oncogene in human cancers, remains a challenging therapeutic target beyond the KRAS G12C mutant. Herein, two series of novel indole-based derivatives (19 compounds) were designed and synthesized as potential KRAS G12D inhibitors. Most compounds displayed potent antiproliferative effects against KRAS G12D mutant tumor cells (CT26 and A427), with IC 50 values in the low micromolar range. Notably, compound 10d demonstrated significant inhibition of KRAS G12D mutant CT26 cell proliferation (IC 50 = 2.04 μM), along with substantial suppression of tumor cell migration (23.8% reduction in wound healing at 2.5 μM) and colony formation (56.9% inhibition at 5 μM), and induction of apoptosis (53.7% elevation at 5 μM). Mechanistic studies revealed that compound 10d induced a 95.6% increase in intracellular ROS levels at 5 μM while concurrently suppressing the PI3K/AKT/MAPK signaling pathway (>60% reduction in pAKT/pERK phosphorylation). In a KRAS G12D -driven CT26 allograft model, intraperitoneal administration of 10d (50 mg/kg) achieved significant tumor growth inhibition (20.1%) without observable toxicity. These findings collectively indicate that 10d is a promising KRAS G12D inhibitor worthy of further study and development as a potential anticancer therapy. • A novel series of indole-based KRAS inhibitors targeting the KRAS G12D mutant was designed through rational structural optimization. • C ompound 10d exhibits significant inhibition of KRAS G12D -mutant CT26 cell proliferation (IC 50 = 2.04 μM), along with substantial suppression of tumor cell migration (23.8% reduction in wound healing) and colony formation (56.9% inhibition) . • Mechanistic studies revealed that inhibition of ERK and AKT phosphorylation significantly increased ROS levels, thereby suppressing tumor cell proliferation, migration, and clonogenicity. • I n vivo studies revealed compound 10d achieves 20.1% tumor growth suppression in KRAS G12D mutant CT26 allografts while maintaining an excellent safety profile.