Frequent downregulation of the runt domain transcription factors RUNX1, RUNX3 and their cofactor CBFB in gastric cancer

Authors

  • Chouhei Sakakura,

    Corresponding author
    1. Graduate School of Medical Science, Surgery and Regenerative Medicine, Surgery and Physiology of Digestive System, Kyoto Prefectural University of Medicine, Kyoto, Japan
    • Department of Digestive Surgery, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kawaramachi-dori, Kyoto 602, Japan
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    • Fax: +81-75-251-5522

  • Akeo Hagiwara,

    1. Graduate School of Medical Science, Surgery and Regenerative Medicine, Surgery and Physiology of Digestive System, Kyoto Prefectural University of Medicine, Kyoto, Japan
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  • Koji Miyagawa,

    1. Graduate School of Medical Science, Surgery and Regenerative Medicine, Surgery and Physiology of Digestive System, Kyoto Prefectural University of Medicine, Kyoto, Japan
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  • Susumu Nakashima,

    1. Graduate School of Medical Science, Surgery and Regenerative Medicine, Surgery and Physiology of Digestive System, Kyoto Prefectural University of Medicine, Kyoto, Japan
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  • Tetsuji Yoshikawa,

    1. Graduate School of Medical Science, Surgery and Regenerative Medicine, Surgery and Physiology of Digestive System, Kyoto Prefectural University of Medicine, Kyoto, Japan
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  • Shuichi Kin,

    1. Graduate School of Medical Science, Surgery and Regenerative Medicine, Surgery and Physiology of Digestive System, Kyoto Prefectural University of Medicine, Kyoto, Japan
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  • Yuenn Nakase,

    1. Graduate School of Medical Science, Surgery and Regenerative Medicine, Surgery and Physiology of Digestive System, Kyoto Prefectural University of Medicine, Kyoto, Japan
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  • Kosei Ito,

    1. Institute of Molecular and Cell Biology and Oncology Research Institute, National University of Singapore, Singapore, Singapore
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  • Hisakazu Yamagishi,

    1. Graduate School of Medical Science, Surgery and Regenerative Medicine, Surgery and Physiology of Digestive System, Kyoto Prefectural University of Medicine, Kyoto, Japan
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  • Shujiro Yazumi,

    1. Division of Gastroenterology and Hepatology, Graduate School of Internal Medicine, Kyoto University, Kyoto, Japan
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  • Tsutomu Chiba,

    1. Division of Gastroenterology and Hepatology, Graduate School of Internal Medicine, Kyoto University, Kyoto, Japan
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  • Yoshiaki Ito

    1. Institute of Molecular and Cell Biology and Oncology Research Institute, National University of Singapore, Singapore, Singapore
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Abstract

Our previous studies suggest that lack of RUNX3 function is causally related to the genesis and progression of human gastric cancer, but potential roles of other members of the RUNX family genes have not yet been reported. We examined the expression of 3 Runt-related (RUNX) genes, RUNX1, RUNX2 and CBFB, in gastric cancer cell lines and primary gastric cancer specimens and compared them to those of RUNX3 reported earlier in conjunction with clinicopathologic factors. Expression of RUNX family genes in 9 gastric cancer cell lines, 56 primary gastric cancer specimens and surrounding normal gastric mucosa were estimated by Northern blot analysis, quantitative RT-PCR and in situ hybridization. Northern blot analysis in gastric cancer cell lines showed downregulation of RUNX1 and RUNX3 in 67% and 78% of the cell lines tested, respectively. The ratio of the average RUNX mRNA/β-actin mRNA ratio (×103) for RUNX1 was 48.0 ± 21.1 vs. 21.4 ± 8.1; RUNX2, 1.1 ± 0.3 vs. 1.0 ± 0.2; RUNX3, 9.2 ± 6.3 vs. 3.1 ± 1.3 and CBFB, 42.0 ± 19.4 vs. 21.0 ± 8.4 (normal vs. tumor, respectively, average ±SD). The basal RUNX2 expression was very weak, and there was no significant change in gastric cancers. Both RUNX1 and RUNX3 showed remarkable downregulation in 62% and 69%, respectively, of surgically resected specimens compared to surrounding mucosa analyzed by quantitative RT-PCR (p < 0.01). Furthermore, CBFB, the gene encoding the cofactor of RUNX1, -2, -3, was also downregulated in significant fraction (32%, p < 0.05). The percentage of downregulation of RUNX1, RUNX3 and CBFB increased as the cancer stage progressed. Tricostatin A and 5′-azacitidin reactivate RUNX3 expression, but they could not reactivate expression of RUNX1 and CBFB in gastric cancer cells, suggesting that the downregulation was due to mechanisms other than methylation of the promoter region. These findings suggest that RUNX1 and CBFB in addition to RUNX3 play some roles in gastric cancers and that roles of RUNX gene family in gastric cancer are more widespread and complex than previously realized.

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