TY - JOUR
T1 - Andrographolide induces cell cycle arrest at G2/M phase and cell death in HepG2 cells via alteration of reactive oxygen species
AU - Li, Jieliang
AU - Cheung, Hon Yeung
AU - Zhang, Zhiqiang
AU - Chan, Gallant K.L.
AU - FONG, David W F
N1 - Funding Information:
The work described in this paper was supported in part by research studentships from City University of Hong Kong to Jieliang Li and Zhiqiang Zhang and fully supported by a grant from CityU (Project No. 7002109). Financial support from Pharmaceutical & Chemical Technology Center Ltd. is also gratefully acknowledged. We thank Dr Desmond K. O'Toole of the City University of Hong Kong for his critical reading of the manuscript, and to all laboratory staffs for their technical helps.
PY - 2007/7/30
Y1 - 2007/7/30
N2 - The cytotoxicity of andrographolide to HepG2 human hepatoma cells was investigated in the present study. Growth of HepG2 cells was affected in the presence of andrographolide with an IC50 of 40.2 μM after 48 h treatment. Flow cytometric analysis and DNA fragmentation assay revealed that andrographolide induced cell cycle arrest at G2/M phase and a late apoptosis of the cells. The occurrence of cell cycle arrest was accompanied by the collapse of mitochondrial membrane potential (MMP) and an intracellular increase of hydrogen peroxide (H2O2) but a decrease of superoxide radicals (O2{radical dot}-) and reduced glutathione. In the treated cells, expression of Bax as well as the transcriptional controller of this pro-apoptotic gene, p53, was upregulated but not other apoptotic proteins such as Bad, Bcl-2 and Bcl-XL. Although the activity of caspase-3, which has direct effect on apoptosis, was also enhanced by the presence of andrographolide, cell death of HepG2 could neither be prevented by a specific inhibitor of capsase-3 nor the pan-caspase inhibitor-zVAD (Val-Ala-Asp), indicating that it was a caspase-independent cell death. Since the overall percentage of apoptotic cells was relatively small throughout the experimental studies, we conclude that the cytotoxic effect of andrographolide on HepG2 cells is primary attributed to the induction of cell cycle arrest via the alteration of cellular redox status.
AB - The cytotoxicity of andrographolide to HepG2 human hepatoma cells was investigated in the present study. Growth of HepG2 cells was affected in the presence of andrographolide with an IC50 of 40.2 μM after 48 h treatment. Flow cytometric analysis and DNA fragmentation assay revealed that andrographolide induced cell cycle arrest at G2/M phase and a late apoptosis of the cells. The occurrence of cell cycle arrest was accompanied by the collapse of mitochondrial membrane potential (MMP) and an intracellular increase of hydrogen peroxide (H2O2) but a decrease of superoxide radicals (O2{radical dot}-) and reduced glutathione. In the treated cells, expression of Bax as well as the transcriptional controller of this pro-apoptotic gene, p53, was upregulated but not other apoptotic proteins such as Bad, Bcl-2 and Bcl-XL. Although the activity of caspase-3, which has direct effect on apoptosis, was also enhanced by the presence of andrographolide, cell death of HepG2 could neither be prevented by a specific inhibitor of capsase-3 nor the pan-caspase inhibitor-zVAD (Val-Ala-Asp), indicating that it was a caspase-independent cell death. Since the overall percentage of apoptotic cells was relatively small throughout the experimental studies, we conclude that the cytotoxic effect of andrographolide on HepG2 cells is primary attributed to the induction of cell cycle arrest via the alteration of cellular redox status.
KW - Andrographolide
KW - Cell cycle arrest
KW - Cell death
KW - HepG2 cell
KW - Mitochondrial membrane potential
KW - Reactive oxygen species
UR - http://www.scopus.com/inward/record.url?scp=34250825923&partnerID=8YFLogxK
U2 - 10.1016/j.ejphar.2007.04.027
DO - 10.1016/j.ejphar.2007.04.027
M3 - Journal article
C2 - 17512926
AN - SCOPUS:34250825923
SN - 0014-2999
VL - 568
SP - 31
EP - 44
JO - European Journal of Pharmacology
JF - European Journal of Pharmacology
IS - 1-3
ER -