Galangin induces apoptosis of hepatocellular carcinoma cells via the mitochondrial pathway.
OBJECTIVE
To investigate the mechanism by which galangin, a polyphenolic compound derived from medicinal herbs, induces apoptosis of hepatocellular carcinoma (HCC) cells.


METHODS
The 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay was used to measure cell viability. Apoptosis was evaluated by in situ uptake of propidium iodide and Hoechst 33258 and was then detected by fluorescence microscopy. Protein expressions were detected by Western blotting. To confirm the apoptotic pathway mediated by galangin, cells were transfected by bcl-2 gene to overexpress Bcl-2 or siRNA to down-regulate Bcl-2 expression.


RESULTS
Galangin (46.25-370.0 micromol/L) exerted an anti-proliferative effect, induced apoptosis, and decreased mitochondrial membrane potential in a dose and time-dependent manner. Treatment with galangin induced apoptosis by translocating the pro-apoptotic protein Bax to the mitochondria, which released apoptosis-inducing factor and cytochrome c into the cytosol. Overexpression of Bcl-2 attenuated galangin-induced HepG2 cell apoptosis, while decreasing Bcl-2 expression enhanced galangin-induced cell apoptosis.


CONCLUSIONS
Our data suggests that galangin mediates apoptosis through a mitochondrial pathway, and may be a potential chemotherapeutic drug for the treatment of HCC.
Zhang
Hai-Tao
HT
Institute of Biochemistry and Molecular Biology, Guangdong Medical College, Zhanjiang 524023, Guangdong Province, China. taohaizhang@tom.com
Luo
Hui
H
Wu
Jun
J
Lan
Liu-Bo
LB
Fan
Da-Hua
DH
Zhu
Kai-Dan
KD
Chen
Xiao-Yi
XY
Wen
Min
M
Liu
Hui-Ming
HM
D017209:Apoptosis / Q000187:drug effects*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D009153:Mutagens / Q000494:pharmacology* / Q000627:therapeutic use; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
D005419:Flavonoids; D009153:Mutagens; D019253:Proto-Oncogene Proteins c-bcl-2; C037032:galangin