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Baicalein Triggers Autophagy and Inhibits the Protein Kinase B/Mammalian Target of Rapamycin Pathway in Hepatocellular Carcinoma HepG2 Cells
Author(s) -
Wang YaFang,
Li Ting,
Tang ZhengHai,
Chang LinLin,
Zhu Hong,
Chen XiuPing,
Wang YiTao,
Lu JinJian
Publication year - 2015
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.5298
Subject(s) - autophagy , baicalein , viability assay , pi3k/akt/mtor pathway , protein kinase b , microbiology and biotechnology , protein kinase a , chemistry , cell growth , kinase , apoptosis , biology , signal transduction , biochemistry , pharmacology
Baicalein (BA), isolated from the Chinese medicinal herb Scutellariae radix (Huangqin in Chinese), is a flavonoid with various pharmacological effects. Herein, we found that BA only slightly reduced the cell viability on HepG2 cells after 24‐h treatment as determined by 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyl tetrazolium bromide (MTT) assay. However, BA (50 μM) effectively blocked the colony formation. Meanwhile, BA remarkably induced the formation of autophagosomes after 24‐h treatment as determined by immunofluorescence with monodansylcadaverine staining as well as transmission electron microscopy, respectively. Moreover, BA obviously up‐regulated the expression of microtubule‐associated protein 1A/1B‐light chain 3‐II in concentration‐dependent and time‐dependent manners in HepG2 cells. When combined with the autophagy inhibitor chloroquine and BA, the cell viability and colony formation were significantly decreased, indicating that BA triggered protective autophagy, which prevented cell death. Further study showed that BA concentration‐dependently and time‐dependently decreased the expression of p‐AKT (S473), p‐ULK1 (S757) and p‐4EBP1 (T37 and S65), suggesting the involvement of protein kinase B (AKT)/mammalian target of rapamycin (mTOR) in BA‐triggered autophagy. Copyright © 2015 John Wiley & Sons, Ltd.