How Temsirolimus works

Temsirolimus (Temsirolimus) is an inhibitor of mTOR, the mammalian target of rapamycin. Temsirolimus binds to an intracellular protein (FKBP-12), and the protein-drug complex inhibits the activity of mTOR, which controls cell division. Inhibition of mTOR activity results in G1 growth arrest in treated tumor cells. When mTOR is inhibited, its ability to phosphorylate p70S6k and S6 ribosomal proteins, which are downstream of mTOR in the PI3 kinase/AKT pathway, is blocked. In in vitro studies using renal cell carcinoma cell lines, temsirolimus inhibited mTOR activity and resulted in reduced levels of the hypoxia-inducible factors HIF-1 and HIF-2α and vascular endothelial growth factor.