A polysaccharide of the marine alga Capsosiphon fulvescens induces apoptosis in AGS gastric cancer cells via an IGF-IR-mediated PI3K/Akt pathway

Authors

  • Mi-Jin Kwon,

    1. Faculty of Food Science and Biotechnology, Pukyong National University, 599-1 Dae-yeon 3-dong, Nam-gu, Busan 608-737, South Korea
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  • Taek-Jeong Nam

    Corresponding author
    1. Faculty of Food Science and Biotechnology, Pukyong National University, 599-1 Dae-yeon 3-dong, Nam-gu, Busan 608-737, South Korea
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Corresponding author. Tel.: +82 51 620 6337; fax: +82 51 620 6330. namtj@pknu.ac.kr

Abstract

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.

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