title: 3-methoxyapigenin modulates β-catenin stability and inhibits Wnt/β-catenin signaling in Jurkat leukemic cells.
abstract: OBJECTIVE
  Aberrant activation of Wnt/β-catenin signaling has been implicated in carcinogenesis. Identification of inhibitors of this pathway may help in cancer therapy. The purpose of this study is to investigate the inhibitory effect of 3-methoxyapigenin (3-MA) with β-catenin/LEF reporter system. The anti-cancer mechanisms in Jurkat leukemic cells were also examined.
  
  
  METHODS
  HEK 293-TOP/FOP reporter cells were used to determine the inhibitory effect of 3-MA on Wnt/β-catenin pathway. We also used Jurkat-TOP reporter cells to confirm the inhibitory effect and the action mechanisms of 3-MA. Target genes and cell proliferation were analyzed by RT-PCR and (3)H-thymidine uptake assay. The effects of 3-MA on β-catenin phosphorylation was determined by Western blotting and by in vitro kinase assays. β-catenin translocation and its transactivation were verified by cellular fractionation and EMSA.
  
  
  RESULTS
  3-MA inhibited Wnt-3A-induced luciferase activity in the HEK 293-TOP/FOP reporter system. Western blotting analysis showed that phosphorylation sites in β-catenin by glycogen synthase kinase-3β (GSK-3β) and casein kinase 2 (CK2) were inhibited by 3-MA in Jurkat. In parallel, in vitro kinase assays verified this effect. As a result, total β-catenin turnover remained balanced by this dual inhibitory effect of 3-MA. Although the β-catenin protein level remained unchanged, 3-MA did inhibit β-catenin translocation. Finally, we found that the β-catenin/LEF transcriptional activity, expression of c-myc and cyclin-D3, and cell proliferation were inhibited by 3-MA.
  
  
  CONCLUSIONS
  3-MA modulates the turnover of β-catenin and suppresses the Wnt/β-catenin signaling pathway through inhibition of β-catenin translocation. We suggested that 3-MA has potential as an anti-cancer drug.
authors: Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan, ROC.
authors: Kai-An
authors: KA
authors: Chuang
authors: Chien-Hui
authors: CH
authors: Lieu
authors: Wei-Jern
authors: WJ
authors: Tsai
authors: Wen-Hsin
authors: WH
authors: Huang
authors: An-Rong
authors: AR
authors: Lee
authors: Yuh-Chi
authors: YC
authors: Kuo
mesh_terms: D000872:Anthocyanins / Q000302:isolation & purification / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification / Q000494:pharmacology*; D047310:Apigenin / Q000302:isolation & purification / Q000494:pharmacology*; D047390:Casein Kinase II / Q000037:antagonists & inhibitors / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D056743:Cyclin D3 / Q000235:genetics; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D016259:Genes, myc / Q000187:drug effects; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D057809:HEK293 Cells; D006801:Humans; D019169:Jurkat Cells; D015458:Leukemia, T-Cell / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D055550:Protein Stability / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D051153:Wnt Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D060449:Wnt Signaling Pathway / Q000187:drug effects*; D030521:Zingiberaceae / Q000737:chemistry*; D051176:beta Catenin / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: C580887:3-methoxyapigeninidin; D000872:Anthocyanins; D000972:Antineoplastic Agents, Phytogenic; D056743:Cyclin D3; D051153:Wnt Proteins; D051176:beta Catenin; D047310:Apigenin; D047390:Casein Kinase II; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3