Protein kinases are enzymes that transfer a phosphate group to the threonine, serine, or tyrosine residues of the target protein, regulating its activity. The activity of these enzymes are very important and strictly regulated in the cell as they promote cell proliferation, survival, and migration. In the case of any dysregulation of these enzymes, they can be associated with cancer initiation and progression. Small-molecule kinase inhibitors approved by the FDA for their improved clinical benefits are currently used in targeted therapy for the treatment of various cancers. So far, there are 62 FDA-approved therapeutic agents targeting different protein kinases, eight of which were approved in 2020. Today, kinase inhibitors are used as FDA approved cancer agents and newly developed ones are evaluated in clinical trials. Those protein kinase inhibitors can be grouped as growth factor receptor inhibitors, Ras/Raf/Mek inhibitors, phosphoinositide 3-kinase (PI3K) and cyclin dependent kinase inhibitors, other targets, and agents such as protein kinase c and 3 phosphoinositide-dependent kinase 1. In this chapter, these kinases, their pathways, and their inhibitors will be discussed in detail.
Part of the book: Protein Kinases