title: (-)-Epigallocatechin gallate regulates CD3-mediated T cell receptor signaling in leukemia through the inhibition of ZAP-70 kinase.
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.
authors.affiliation: Hormel Institute, University of Minnesota, Austin, Minnesota 55912, USA.
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Shim
authors.forename: Hong Seok
authors.initials: HS
authors.lastname: Choi
authors.forename: Angelo
authors.initials: A
authors.lastname: Pugliese
authors.forename: Sung-Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Chae
authors.forename: Bu Young
authors.initials: BY
authors.lastname: Choi
authors.forename: Ann M
authors.initials: AM
authors.lastname: Bode
authors.forename: Zigang
authors.initials: Z
authors.lastname: Dong
mesh_terms: D017209:Apoptosis; D017252:CD3 Complex / Q000096:biosynthesis*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D045744:Cell Line, Tumor; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D019169:Jurkat Cells; D007938:Leukemia / Q000378:metabolism*; D008954:Models, Biological; D008968:Molecular Conformation; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000378:metabolism*
chemical_list: D017252:CD3 Complex; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D002392:Catechin; C045651:epigallocatechin gallate; D051746:ZAP-70 Protein-Tyrosine Kinase