A polysaccharide of the marine alga Capsosiphon fulvescens induces apoptosis in AGS gastric cancer cells via an IGF-IR-mediated PI3K/Akt pathway.
Because seaweed extracts have recently been found to have antioxidant and anti-tumor activities, we analyzed a hot-water-soluble polysaccharide (PS) of the marine alga Capsosiphon fulvescens for its potential as a functional foodstuff by determining its effects on cell growth and DNA synthesis. MTS assays showed that the C. fulvescens PS (Cf-PS) significantly inhibited the proliferation of cultured human cancer cells in a dose-dependent manner. Cf-PS-treated AGS cells exhibited a marked increase in caspase-3 activation and a decrease in Bcl-2 expression. In addition, phosphorylation of insulin-like growth factor-I receptor (IGF-IR) was decreased in Cf-PS-treated AGS cells as compared to non-treated control cells, which is consistent with PI3-kinase (PI3K)/Akt activation. Cf-PS also decreased IGF-I-stimulated recruitment of p85 to IGF-IR and IRS-1. These results indicate that Cf-PS inhibits cell proliferation and induces apoptosis by inhibiting IGF-IR signaling and the PI3K/Akt pathway.
Kwon
Mi-Jin
MJ
Faculty of Food Science and Biotechnology, Pukyong National University, 599-1 Dae-yeon 3-dong, Nam-gu, Busan 608-737, South Korea.
Nam
Taek-Jeong
TJ
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D000460:Chlorophyta / Q000737:chemistry*; D015536:Down-Regulation; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000502:physiology; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D011134:Polysaccharides / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology*; D051381:Rats; D017526:Receptor, IGF Type 1 / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects; D013274:Stomach Neoplasms
D000970:Antineoplastic Agents; D011134:Polysaccharides; D007334:Insulin-Like Growth Factor I; D019869:Phosphatidylinositol 3-Kinases; D017526:Receptor, IGF Type 1; D051057:Proto-Oncogene Proteins c-akt