Hypoxia enhances gene expression of inducible nitric oxide synthase and matrix metalloproteinase-9 in ras/myc-transformed serum-free mouse embryo cells under simulated inflammatory and infectious conditions

Authors

  • Hideaki Yamaguchi,

    Corresponding author
    1. Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Aomori University, 2-3-1 Kobata, Aomori 030-0943, Japan
    2. Graduate School of Environmental Sciences, Aomori University, 2-3-1 Kobata, Aomori 030-0943, Japan
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    • These authors contributed equally to this work.

  • Yumi Kidachi,

    1. Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Aomori University, 2-3-1 Kobata, Aomori 030-0943, Japan
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    • These authors contributed equally to this work.

  • Hironori Umetsu,

    1. Laboratory of Food Chemistry, Department of Life Sciences, Junior College, Gifu Shotoku Gakuen University, 1-38 Nakauzura, Gifu 500-8288, Japan
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  • Kazuo Ryoyama

    1. Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Aomori University, 2-3-1 Kobata, Aomori 030-0943, Japan
    2. Graduate School of Environmental Sciences, Aomori University, 2-3-1 Kobata, Aomori 030-0943, Japan
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Corresponding author. Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Aomori University, 2-3-1 Kobata, Aomori 030-0943, Japan. Tel.: +81 17 738 2001x5515; fax: +81 17 738 2030. yamaguch@aomori-u.ac.jp

Abstract

Ras/myc-transformed serum-free mouse embryo (ras/myc SFME) cells were treated with interferon-gamma (IFN-γ; 100 U/ml) and/or lipopolysaccharide (LPS; 0.5 μg/ml) for 24 h to simulate inflammatory and infectious conditions and investigate their effects on the expression of inducible nitric oxide synthase (iNOS) mRNA, nitric oxide (NO) and matrix metalloproteinase-9 (MMP-9). In addition, aminoguanidine (AG; 1 mM), a NOS inhibitor, S-nitroso-N-acetyl-dl-penicillamine (SNAP; 10–200 μM), an NO donor or (±)-N-[(E)-4-ethyl-2-[(Z)-hydroxyimino]-5-nitro-3-hexene-1-yl]-3-pyridine carboxamide (NOR4; 10–200 μM), an NO donor, were added to analyze possible associations of NO with MMP-9. Tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2 were also measured to analyze possible relationships of NO with the MMP-9/TIMP balance. Furthermore, the cells were treated with 1% O2 under the simulated inflammatory and infectious conditions and the mRNA expressions of iNOS and MMP-9 were analyzed to investigate the possible effects of hypoxia on the expression of genes involved in tumor malignant progression and distant metastasis. Co-treatment with IFN-γ and LPS increased the expression levels of iNOS mRNA, NO and MMP-9, but NO may not be directly associated with MMP-9 or the MMP-9/TIMP balance. Treatment with 1% O2 markedly increased the gene expression levels of iNOS and MMP-9, indicating that ras/myc SFME cells alter the expression levels of tumor-associated genes and possibly enhance their malignancy as cancer cells under inflammatory, infectious and hypoxic conditions.

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