| Structural highlights
Disease
[ITK_HUMAN] Defects in ITK are the cause of lymphoproliferative syndrome EBV-associated autosomal type 1 (LPSA1) [MIM:613011]. LPSA1 is a rare immunodeficiency characterized by extreme susceptibility to infection with Epstein-Barr virus (EBV). Inadequate immune response to EBV can have a fatal outcome. Clinical features include splenomegaly, lymphadenopathy, anemia, thrombocytopenia, pancytopenia, recurrent infections. There is an increased risk for lymphoma.[1]
Function
[ITK_HUMAN] Tyrosine kinase that plays an essential role in regulation of the adaptive immune response. Regulates the development, function and differentiation of conventional T-cells and nonconventional NKT-cells. When antigen presenting cells (APC) activate T-cell receptor (TCR), a series of phosphorylation lead to the recruitment of ITK to the cell membrane, in the vicinity of the stimulated TCR receptor, where it is phosphorylated by LCK. Phosphorylation leads to ITK autophosphorylation and full activation. Once activated, phosphorylates PLCG1, leading to the activation of this lipase and subsequent cleavage of its substrates. In turn, the endoplasmic reticulum releases calcium in the cytoplasm and the nuclear activator of activated T-cells (NFAT) translocates into the nucleus to perform its transcriptional duty. Phosphorylates 2 essential adapter proteins: the linker for activation of T-cells/LAT protein and LCP2. Then, a large number of signaling molecules such as VAV1 are recruited and ultimately lead to lymphokine production, T-cell proliferation and differentiation.[2] [3] [4]
Publication Abstract from PubMed
The medicinal chemistry community has directed considerable efforts toward the discovery of selective inhibitors of interleukin-2 inducible T-cell kinase (ITK), given its role in T-cell signaling downstream of the T-cell receptor (TCR) and the implications of this target for inflammatory disorders such as asthma. We have previously disclosed a structure- and property-guided lead optimization effort which resulted in the discovery of a new series of tetrahydroindazole-containing selective ITK inhibitors. Herein we disclose further optimization of this series that resulted in further potency improvements, reduced off-target receptor binding liabilities, and reduced cytotoxicity. Specifically, we have identified a correlation between the basicity of solubilizing elements in the ITK inhibitors and off-target antiproliferative effects, which was exploited to reduce cytotoxicity while maintaining kinase selectivity. Optimized analogues were shown to reduce IL-2 and IL-13 production in vivo following oral or intraperitoneal dosing in mice.
Tetrahydroindazoles as Interleukin-2 Inducible T-Cell Kinase Inhibitors. Part II. Second-Generation Analogues with Enhanced Potency, Selectivity, and Pharmacodynamic Modulation in Vivo.,Burch JD, Barrett K, Chen Y, DeVoss J, Eigenbrot C, Goldsmith R, Ismaili MH, Lau K, Lin Z, Ortwine DF, Zarrin AA, McEwan PA, Barker JJ, Ellebrandt C, Kordt D, Stein DB, Wang X, Chen Y, Hu B, Xu X, Yuen PW, Zhang Y, Pei Z J Med Chem. 2015 Apr 16. PMID:25844760[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Huck K, Feyen O, Niehues T, Ruschendorf F, Hubner N, Laws HJ, Telieps T, Knapp S, Wacker HH, Meindl A, Jumaa H, Borkhardt A. Girls homozygous for an IL-2-inducible T cell kinase mutation that leads to protein deficiency develop fatal EBV-associated lymphoproliferation. J Clin Invest. 2009 May;119(5):1350-8. PMID:19425169
- ↑ Perez-Villar JJ, Whitney GS, Sitnick MT, Dunn RJ, Venkatesan S, O'Day K, Schieven GL, Lin TA, Kanner SB. Phosphorylation of the linker for activation of T-cells by Itk promotes recruitment of Vav. Biochemistry. 2002 Aug 27;41(34):10732-40. PMID:12186560
- ↑ Grasis JA, Browne CD, Tsoukas CD. Inducible T cell tyrosine kinase regulates actin-dependent cytoskeletal events induced by the T cell antigen receptor. J Immunol. 2003 Apr 15;170(8):3971-6. PMID:12682224
- ↑ Sela M, Bogin Y, Beach D, Oellerich T, Lehne J, Smith-Garvin JE, Okumura M, Starosvetsky E, Kosoff R, Libman E, Koretzky G, Kambayashi T, Urlaub H, Wienands J, Chernoff J, Yablonski D. Sequential phosphorylation of SLP-76 at tyrosine 173 is required for activation of T and mast cells. EMBO J. 2011 Jul 1;30(15):3160-72. doi: 10.1038/emboj.2011.213. PMID:21725281 doi:10.1038/emboj.2011.213
- ↑ Burch JD, Barrett K, Chen Y, DeVoss J, Eigenbrot C, Goldsmith R, Ismaili MH, Lau K, Lin Z, Ortwine DF, Zarrin AA, McEwan PA, Barker JJ, Ellebrandt C, Kordt D, Stein DB, Wang X, Chen Y, Hu B, Xu X, Yuen PW, Zhang Y, Pei Z. Tetrahydroindazoles as Interleukin-2 Inducible T-Cell Kinase Inhibitors. Part II. Second-Generation Analogues with Enhanced Potency, Selectivity, and Pharmacodynamic Modulation in Vivo. J Med Chem. 2015 Apr 16. PMID:25844760 doi:http://dx.doi.org/10.1021/jm501998m
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