3-Methoxyapigenin modulates β-catenin stability and inhibits Wnt/β-catenin signaling in Jurkat leukemic cells

• Published in: Life sciences (1973) 2013-04, Vol.92 (12), p.677-686
• Main Authors: Chuang, Kai-An, Lieu, Chien-Hui, Tsai, Wei-Jern, Huang, Wen-Hsin, Lee, An-Rong, Kuo, Yuh-Chi
• Format: Article
• Language: English
• Subjects: Anthocyanins - isolation & purification; Anthocyanins - pharmacology; Anti-cancer; antineoplastic agents; Antineoplastic Agents, Phytogenic - isolation & purification; Antineoplastic Agents, Phytogenic - pharmacology; Apigenin - isolation & purification; Apigenin - pharmacology; beta Catenin - analysis; beta Catenin - antagonists & inhibitors; beta Catenin - metabolism; carcinogenesis; casein; Casein Kinase II - antagonists & inhibitors; Casein Kinase II - metabolism; cell proliferation; Cell Proliferation - drug effects; Cyclin D3 - genetics; fractionation; Gene Expression Regulation, Leukemic - drug effects; genes; Genes, myc - drug effects; glycogen (starch) synthase; Glycogen Synthase Kinase 3 - antagonists & inhibitors; Glycogen Synthase Kinase 3 - metabolism; Glycogen Synthase Kinase 3 beta; Glycogen synthase kinase-3β (GSK-3β); glycogen synthase kinases; HEK293 Cells; Humans; Jurkat Cells; Leukemia; Leukemia, T-Cell - drug therapy; Leukemia, T-Cell - genetics; Leukemia, T-Cell - metabolism; luciferase; mechanism of action; phosphorylation; Protein Stability - drug effects; Protein Transport - drug effects; reverse transcriptase polymerase chain reaction; signal transduction; therapeutics; transcription (genetics); transcriptional activation; Western blotting; Wnt; Wnt Proteins - antagonists & inhibitors; Wnt Proteins - metabolism; Wnt Signaling Pathway - drug effects; Zingiberaceae - chemistry; β-catenin
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/j.lfs.2012.12.007

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. 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 3H-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. 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. 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.