PLK1-IN-10 (Compound 4Bb) is an orally active PLK1 PBD (polo-box domain) inhibitor. PLK1-IN-10 blocks the interaction of PLK1 with the cell division regulator protein 1 (PRC1) and decreases the protein expression of the CDK1-Cyclin B1 complex. PLK1-IN-10 reacts with glutathione (GSH) to increase cellular oxidative stress, ultimately leading to cell death.