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Vascular endothelial growth factor protects hepatoma cells against oxidative stress‐induced cell death
Author(s) -
Osada Shinji,
Imai Hisashi,
Tomita Hiroyuki,
Tokuyma Yasuharu,
Okumura Naoki,
Sakashita Fumio,
oka Kenichi,
Sugiyama Yasuyuki
Publication year - 2006
Publication title -
journal of gastroenterology and hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.214
H-Index - 130
eISSN - 1440-1746
pISSN - 0815-9319
DOI - 10.1111/j.1440-1746.2006.04223.x
Subject(s) - vascular endothelial growth factor , western blot , oxidative stress , mapk/erk pathway , microbiology and biotechnology , hepatocyte growth factor , angiogenesis , kinase , programmed cell death , viability assay , extracellular , medicine , biology , endocrinology , cell , apoptosis , biochemistry , receptor , vegf receptors , gene
Background: The aim of the present study was to examine coordination of the vascular endothelial growth factor (VEGF) and VEGF receptor (Flk‐1) system and to study control of VEGF expression by oxidative stress, which is considered a model for chronic liver disease. Methods: Cell viability was determined by test method with 3‐[4, 5‐dimethylthiazol‐2‐yl]‐2, 5‐dephenyl tetrazolium bromide (MTT). Expressions of cellular proteins were evaluated by western blot analysis. Results: The c‐Met tyrosine phosphorylation in PLC/PRF/5 hepatoma cells was increased by treatment with 20 ng/mL hepatocyte growth factor (HGF), and extracellular signal‐regulated kinase (ERK) was also activated. Although Flk‐1 was phosphorylated in response to VEGF (>50 ng/mL), phosphorylated ERK was not detected at these concentrations. A total of 5.0 and 10 µmol/L hydrogen peroxide (H 2 O 2 ) caused cell death in a dose‐dependent manner after 24 h. On western blot analysis at 1 h with H 2 O 2 , rapid phosphorylation of both ERK1/2 and c‐Jun NH 2 ‐terminal kinase (JNK) was observed. In the first 6 h, H 2 O 2 induced cell death for 58.4 ± 6.8%, whereas the presence of 100 ng/mL VEGF improved the survival rate to 77.2 ± 4.2%. The VEGF significantly decreased H 2 O 2 ‐induced cell death after 12 h, whereas HGF (20 ng/mL) did not have a similar effect. When cells were incubated with 5 µmol/L H 2 O 2 , expression of VEGF protein was detected. Furthermore, H 2 O 2 ‐induced phosphorylation of ERK and JNK was also reduced by VEGF (100 ng/mL). In contrast, HGF did not induce phosphorylation of ERK and JNK. Conclusion: Hepatoma cells might be able to survive under continuous oxidative stress through expression of VEGF.