Targeting the cell division cycle in cancer: CDK and cell cycle checkpoint kinase inhibitors

The cyclin-dependent kinase (CDK) family of serine/threonine kinases regulate progression through each stage of the cell division cycle and as such are major targets for deregulation in cancer. This has led to the development of several small-molecule inhibitors of CDKs as potential therapeutic agents for the treatment of this disease. Progression through the cell cycle is also monitored at several positions known as cell cycle checkpoints, two of which occur during G(1) and G(2) in response to DNA damage. These are often defective in cancer, leading to the suggestion that inhibition of one or both of the cell cycle checkpoint kinases CHK1 and CHK2 may drive a cancer cell that already has defects in its cell cycle checkpoints towards death.