Discovery of a novel PLK1 inhibitor with high inhibitory potency using a combined virtual screening strategy.

PLK1 is essential for cell cycle regulation and proliferation, and its elevated expression in prostate cancer is associated with high tumour grade. Therefore, PLK1 inhibition is considered a promising strategy for the treatment of prostate cancer. Here, we identified five compounds (Hits 1-5) targeting the kinase domain (KD) of PLK1 using a combined virtual screening approach. Hits 1-5 all had picomolar (pM) inhibitory potency against PLK1. Notably, Hit-4 showed the strongest inhibitory activity against PLK1 (IC₅₀ = 22.61 ± 1.12 pM) and displayed high selectivity for PLK1. Meanwhile, molecular dynamics (MD) simulations revealed that the complex formed by Hit-4 and PLK1 remained stable. Importantly, Hit-4 exhibited potent inhibitory effects on the proliferation of DU-145 prostate cancer cells (IC₅₀ = 0.09 ± 0.01 nM). In conclusion, Hit-4 is a potent and highly selective antitumor candidate with therapeutic potential for prostate cancer.