JNK結合分子による細胞接着斑と運動極性形成制御機構の解析

HT1080細胞のI型コラーゲンおよびファイブロネクチン(FN)上での細胞運動はMMP阻害剤BB94により抑制され、ECM分解の減少、細胞接着斑の過形成と運動極性の喪失が認められた。一方、MT1-MMPの過剰発現はECM分解、細胞運動と細胞接着斑の代謝回転を誘導し、阻害変異体の発現でその抑制が認められた。HT1080細胞のBB94処理は細胞接着により誘導されるERK活性化を抑制した。以上の結果からMT1-MMPは細胞接着により誘導されるERK活性化を調節することにより細胞接着斑の代謝回転と細胞運動を制御していることが示唆された(T. Takino et al., Experimental Cell Research,2006)。 細胞運動時、MT1-MMPは細胞接着斑の集積と代謝回転が頻繁に起こる運動先端部の内側でECMを分解していた。細胞接着斑におけるMT1-MMPの機能に着目し、FAKの細胞接着斑標的ドメインをMT1-MMPとMT1-MMPの阻害変異体に付与し、細胞接着斑におけるMT1-MMPの役割を解析した。細胞接着斑に標的したMT1-MMPはFNへの接着後、迅速に細胞接着斑でFNを分解した。 細胞接着斑に標的したMT1-MMPの阻害変異体はMT1-MMP発現細胞におけるFN分解と細胞運動、3次元ECMへの細胞浸潤を顕著に抑制した。以上の結果から、細胞接着斑におけるMT1-MMP機能の重要性と、その活性阻害ががん浸潤・転移抑制に効果的であることが示された(T. Takino et al., Cancer Research, 2007)。Membrane-type 1 matrix metalloproteinase (MT1-MMP) has been implicated in tumor invasion and metastasis. We previously reported that extracellular matrix degradation by MT1-MMP regulates cell migration via modulating sustained integrin-mediated signals. In this study, MT1-MMP-expressing cells were plated onto fibronectin-coated plates and monitored for cell-matrix adhesion formation and fibronectin degradation. The fibronectin was degraded and removed in line with the cell migration track. The migrating cells showed a polarized morphology and were in contact with the edge of fibronectin through the leading edge in which cell-matrix adhesions are concentrated. Expression of MT1-MMP targeted to cell-matrix adhesions by fusing with the focal adhesion targeting (FAT) domain of focal adhesion kinase (FAK) promoted the initial fibronectin lysis at the cell periphery immediately after adhesion. These results suggest that fibronectin is degraded by MT1-MMP located at cell-matrix adhesions which are concentrated at the leading edge of the migrating cells. lb inhibit MT1-MMP at cell-matrix adhesion, the dominant negative form of MT1-MMP (MT1-Pex) was targeted to the cell-matrix adhesion by fusing with the FAT domain (MT1-Pex-FAT). MT1-Pex-FAT accumulated at cell-matrix adhesions and inhibited fibronectin degradation as well as FAK phosphorylation more effectively than parental MT1-Pex. MT1-Pex-FAT was also shown to suppress the invasion of tumor cells into 3-dimensional collagen gel more strongly than MT1-Pex. These results suggest that MT1-MMP-mediated extracellular matrix lysis at cell-matrix adhesions induces the establishment of cell polarity, which facilitates cell-matrix adhesion turnover and subsequent cell migration. This model highlights the role of MT1-MMP at the leading edge of migrating cells.研究課題/領域番号:18590287, 研究期間(年度):2006–2007出典：「JNK結合分子による細胞接着斑と運動極性形成制御機構の解析」研究成果報告書 課題番号18590287 (KAKEN：科学研究費助成事業データベース（国立情報学研究所）) 本文データは著者版報告書より作