, Volume 19, Issue 4, pp 682–697 | Cite as

Licochalcone A induces apoptosis through endoplasmic reticulum stress via a phospholipase Cγ1-, Ca2+-, and reactive oxygen species-dependent pathway in HepG2 human hepatocellular carcinoma cells

  • A-Young Choi
  • Ji Hyun Choi
  • Keun-Young Hwang
  • Yeon Ju Jeong
  • Wonchae Choe
  • Kyung-Sik Yoon
  • Joohun Ha
  • Sung Soo Kim
  • Jang Hyun Youn
  • Eui-Ju YeoEmail author
  • Insug KangEmail author
Original Paper


Licochalcone A (LicA), an estrogenic flavonoid, induces apoptosis in multiple types of cancer cells. In this study, the molecular mechanisms underlying the anti-cancer effects of LicA were investigated in HepG2 human hepatocellular carcinoma cells. LicA induced apoptotic cell death, activation of caspase-4, -9, and -3, and expression of endoplasmic reticulum (ER) stress-associated proteins, including C/EBP homologous protein (CHOP). Inhibition of ER stress by CHOP knockdown or treatment with the ER stress inhibitors, salubrinal and 4-phenylbutyric acid, reduced LicA-induced cell death. LicA also induced reactive oxygen species (ROS) accumulation and the anti-oxidant N-acetylcysteine reduced LicA-induced cell death and CHOP expression. In addition, LicA increased the levels of cytosolic Ca2+, which was blocked by 2-aminoethoxydiphenyl borate (an antagonist of inositol 1,4,5-trisphosphate receptor) and BAPTA-AM (an intracellular Ca2+ chelator). 2-Aminoethoxydiphenyl borate and BAPTA-AM inhibited LicA-induced cell death. Interestingly, LicA induced phosphorylation of phospholipase Cγ1 (PLCγ1) and inhibition of PLCγ1 reduced cell death and ER stress. Moreover, the multi-targeted receptor tyrosine kinase inhibitors, sorafenib and sunitinib, reduced LicA-induced cell death, ER stress, and cytosolic Ca2+ and ROS accumulation. Finally, LicA induced phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2) and c-Met receptor and inhibition of both receptors by co-transfection with VEGFR2 and c-Met siRNAs reversed LicA-induced cell death, Ca2+ increase, and CHOP expression. Taken together, these findings suggest that induction of ER stress via a PLCγ1-, Ca2+-, and ROS-dependent pathway may be an important mechanism by which LicA induces apoptosis in HepG2 hepatocellular carcinoma cells.


Apoptosis Calcium ER stress HepG2 cells Licochalcone A PLCγ1 



This work was supported by the National Research Foundation of Korea (NRF) Grants funded by the Korea government (MSIP, No. 2012-0009380).

Conflict of interest

No conflict of interest is declared.


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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • A-Young Choi
    • 1
  • Ji Hyun Choi
    • 1
  • Keun-Young Hwang
    • 1
  • Yeon Ju Jeong
    • 1
  • Wonchae Choe
    • 1
  • Kyung-Sik Yoon
    • 1
  • Joohun Ha
    • 1
  • Sung Soo Kim
    • 1
  • Jang Hyun Youn
    • 1
    • 2
  • Eui-Ju Yeo
    • 3
    Email author
  • Insug Kang
    • 1
    Email author
  1. 1.Department of Biochemistry and Molecular Biology, School of Medicine, Medical Research Center for Bioreaction to Reactive Oxygen Species, Biomedical Science InstituteKyung Hee UniversitySeoulRepublic of Korea
  2. 2.Department of Physiology and Biophysics, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUSA
  3. 3.Department of Biochemistry, School of MedicineGachon UniversityInchonRepublic of Korea

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