(-)-Epigallocatechin gallate regulates CD3-mediated T cell receptor signaling in leukemia through the inhibition of ZAP-70 kinase

J Biol Chem. 2008 Oct 17;283(42):28370-9. doi: 10.1074/jbc.M802200200. Epub 2008 Aug 7.

Abstract

The zeta chain-associated 70-kDa protein (ZAP-70) of tyrosine kinase plays a critical role in T cell receptor-mediated signal transduction and the immune response. A high level of ZAP-70 expression is observed in leukemia, which suggests ZAP-70 as a logical target for immunomodulatory therapies. (-)-Epigallocatechin gallate (EGCG) is one of the major green tea catechins that is suggested to have a role as a preventive agent in cancer, obesity, diabetes, and cardiovascular disease. Here we identified ZAP-70 as an important and novel molecular target of EGCG in leukemia cells. ZAP-70 and EGCG displayed high binding affinity (Kd = 0.6207 micromol/liter), and additional results revealed that EGCG effectively suppressed ZAP-70, linker for the activation of T cells, phospholipase Cgamma1, extracellular signaling-regulated kinase, and MAPK kinase activities in CD3-activated T cell leukemia. Furthermore, the activation of activator protein-1 and interleukin-2 induced by CD3 was dose-dependently inhibited by EGCG treatment. Notably, EGCG dose-dependently induced caspase-mediated apoptosis in P116.cl39 ZAP-70-expressing leukemia cells, whereas P116 ZAP-70-deficient cells were resistant to EGCG treatment. Molecular docking studies, supported by site-directed mutagenesis experiments, showed that EGCG could form a series of intermolecular hydrogen bonds and hydrophobic interactions within the ATP binding domain, which may contribute to the stability of the ZAP-70-EGCG complex. Overall, these results strongly indicated that ZAP-70 activity was inhibited specifically by EGCG, which contributed to suppressing the CD3-mediated T cell-induced pathways in leukemia cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • CD3 Complex / biosynthesis*
  • Catechin / analogs & derivatives*
  • Catechin / pharmacology
  • Cell Line, Tumor
  • Gene Expression Regulation, Leukemic*
  • Humans
  • Interleukin-2 / metabolism
  • Jurkat Cells
  • Leukemia / metabolism*
  • Models, Biological
  • Molecular Conformation
  • Receptors, Antigen, T-Cell / metabolism*
  • Signal Transduction*
  • T-Lymphocytes / metabolism
  • ZAP-70 Protein-Tyrosine Kinase / metabolism*

Substances

  • CD3 Complex
  • Interleukin-2
  • Receptors, Antigen, T-Cell
  • Catechin
  • epigallocatechin gallate
  • ZAP-70 Protein-Tyrosine Kinase