Identification and validation of natural product-based KRAS^G12D inhibitors through structure-based virtual screening,...

KRAS^G12D is a common cancer-driving mutation that fuels the progression of several aggressive cancers, particularly pancreatic, colorectal, and lung cancers. Despite its well-established role in tumor development, effective therapeutic options that directly target KRAS^G12D remain limited. In this study, a structure-based virtual screening strategy was employed to identify potential KRAS^G12D inhibitors. Molecular docking was used to screen a library of traditional Chinese medicine (TCM) compounds, followed by ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) profiling. The top five drug-like candidates were subjected to 200 ns molecular dynamics simulations and MM-GBSA binding free-energy calculations. Three selected compounds were further evaluated in vitro, among which Rubimaillin showed notable anticancer activity with IC₅₀ values of 1.10 ± 0.12 µM and 2.07 ± 0.02 µM against MIA PaCa-2 and PANC-1 cell lines, respectively, while displaying low toxicity toward non-tumorous HEK-293 cells (CC₅₀ = 38.92 ± 8.49 µM). Rubimaillin also significantly inhibited cell migration and modulated key oncogenic biomarkers, including reduced KRAS protein levels, downregulation of BCL2, SOX9, and LC3 gene expression, and upregulation of p53 expression. Overall, these findings suggest that Rubimaillin may represent a suitable candidate for further investigation as a KRAS^G12D-targeted anticancer agent and demonstrate the value of integrating computational screening with natural product-based drug discovery approaches.