Autocrine motility factor enhances hepatoma cell invasion across the basement membrane through activation of β1 integrins

Authors

  • Takuji Torimura,

    Corresponding author
    1. The Second Department of Medicine and Research Center for Innovative Cancer Therapy, Kurume University School of Medicine, Kurume City
    • The Second Department of Medicine, Kurume University School of Medicine, 67 Asahi-machi, 830-0011 Kurume City, Japan. fax: (81) 942-34-2623
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  • Takato Ueno,

    1. The Second Department of Medicine and Research Center for Innovative Cancer Therapy, Kurume University School of Medicine, Kurume City
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  • Motoaki Kin,

    1. The Second Department of Medicine and Research Center for Innovative Cancer Therapy, Kurume University School of Medicine, Kurume City
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  • Riko Harada,

    1. The Second Department of Medicine and Research Center for Innovative Cancer Therapy, Kurume University School of Medicine, Kurume City
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  • Toru Nakamura,

    1. The Second Department of Medicine and Research Center for Innovative Cancer Therapy, Kurume University School of Medicine, Kurume City
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  • Takumi Kawaguchi,

    1. The Second Department of Medicine and Research Center for Innovative Cancer Therapy, Kurume University School of Medicine, Kurume City
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  • Masaru Harada,

    1. The Second Department of Medicine and Research Center for Innovative Cancer Therapy, Kurume University School of Medicine, Kurume City
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  • Ryukichi Kumashiro,

    1. The Second Department of Medicine and Research Center for Innovative Cancer Therapy, Kurume University School of Medicine, Kurume City
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  • Hideomi Watanabe,

    1. Department of Orthopedic Surgery, Gunma University School of Medicine, Maebashi City
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  • Raz Avraham,

    1. Division of Basic Research, KARMANOS Cancer Institute, Wane State University School of Medicine, Detroit, MI.
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  • Michio Sata

    1. The Second Department of Medicine and Research Center for Innovative Cancer Therapy, Kurume University School of Medicine, Kurume City
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Abstract

Autocrine motility factor/phosphohexose isomerase (AMF/PHI) is a cytokine that is linked to tumor invasion and metastasis. In hepatocellular carcinoma (HCC) tissues, hepatoma cells produce AMF/PHI and its receptor, Mr 78,000 glycoprotein (gp78), is strongly detected in hepatoma cells invading into the stroma and tumor thrombi in the portal vein. Here, we investigated the mechanism of hepatoma cell invasion through Matrigel induced by AMF/PHI using 3 hepatoma cell lines. Production of AMF/PHI, phosphorylation of MEK1/2, and Rho activity were investigated by immunoblotting. Expression of AMF/PHI and gp78 was observed by confocal fluorescence microscopy. The influence of AMF/PHI on activated integrin β1 subunit expression was evaluated by flow cytometry. Changes in invasion, adhesion, and motility induced by AMF/PHI were evaluated using chemoinvasion, adhesion, and phagokinetic track motility assays. The effect of AMF/PHI on matrix metalloproteinase (MMP) secretion was evaluated by gelatin zymography. Hepatoma cells produced AMF/PHI and expressed gp78. Although AMF/PHI was ubiquitously detected, gp78 was strongly expressed in migrating cells. AMF/PHI induced up-regulation of activated integrin β1 subunit expression. AMF/PHI stimulated hepatoma cell invasion through Matrigel, and stimulated the adhesion, motility, and MMP-2 secretion of hepatoma cells. The latter effects were suppressed by the function-blocking antibody for integrin β1 subunit. AMF/PHI also enhanced Rho activity and the phosphorylation of MEK1 and MEK 2. Our results indicate that AMF/PHI enhances hepatoma cell invasion through Matrigel in an autocrine manner by stimulating the adhesion, motility, and MMP-2 secretion of these cells through activation of β1 integrins.

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