Tyrosine kinase inhibitor

Crystal structure of the second generation Bcr-Abl tyrosine-kinase inhibitor nilotinib (red) in complex with an Abl kinase domain (blue). Nilotinib is used to treat chronic myelogenous leukemia (CML), a hematological malignancy.

A tyrosine kinase inhibitor (TKI) is a pharmaceutical drug that inhibits tyrosine kinases. Tyrosine kinases are enzymes responsible for the activation of many proteins by signal transduction cascades. The proteins are activated by adding a phosphate group to the protein (phosphorylation), a step that TKIs inhibit. TKIs are typically used as anticancer drugs. For example, they have substantially improved outcomes in chronic myelogenous leukemia. They have also been used to treat other diseases, such as idiopathic pulmonary fibrosis.

They are also called tyrphostins, the short name for "tyrosine phosphorylation inhibitor", originally coined in a 1988 publication,[1] which was the first description of compounds inhibiting the catalytic activity of the epidermal growth factor receptor (EGFR).

The 1988 study was the first demonstration of a systematic search and discovery of small-molecular-weight inhibitors of tyrosine phosphorylation, which do not inhibit protein kinases that phosphorylate serine or threonine residues and can discriminate between the kinase domains of the EGFR and that of the insulin receptor. It was further shown that in spite of the conservation of the tyrosine-kinase domains one can design and synthesize tyrphostins that discriminate between even closely related protein tyrosine kinases such as EGFR and its close relative HER2.[2][3]

  1. ^ Yaish P, Gazit A, Gilon C, Levitzki A (1988). "Blocking of EGF-dependent cell proliferation by EGF receptor kinase inhibitors". Science. 242 (4880): 933–935. Bibcode:1988Sci...242..933Y. doi:10.1126/science.3263702. PMID 3263702. S2CID 9593087.
  2. ^ Gazit A, Osherov N, Posner I, Yaish P, Poradosu E, Gilon C, Levitzki A (1991). "Tyrphostins. 2. Heterocyclic and alpha-substituted benzylidenemalononitrile tyrphostins as potent inhibitors of EGF receptor and ErbB2/neu tyrosine kinases". J Med Chem. 34 (6): 1896–907. doi:10.1021/jm00110a022. PMID 1676428.
  3. ^ Osherov N, Gazit A, Gilon C, Levitzki A (1993). "Selective inhibition of the epidermal growth factor and HER2/neu receptors by tyrphostins". J Biol Chem. 268 (15): 11134–42. doi:10.1016/S0021-9258(18)82102-0. PMID 8098709.