Sato T, Iwai M, Sakai T, Sato H, Seiki M, Mori Y, Ito A
Department of Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Japan.
Br J Cancer. 1999 Jun;80(8):1137-43. doi: 10.1038/sj.bjc.6690477.
Matrix metalloproteinase 2 (MMP-2)/gelatinase A plays an important role in tumour invasion and metastasis. Since MMP-2 is secreted as an inactive form (proMMP-2) from tumour and neighbouring stroma cells, the activation process is necessary to express the enzymic activity for degradation of extracellular matrix components. We herein reported that the activation of proMMP-2 was induced in human squamous carcinoma cells co-cultured with normal human dermal fibroblasts. When A431 cells were co-cultured with human fibroblasts at various cell ratios, 72-kDa proMMP-2 was converted to a 62-kDa active form through the appearance of a 64-kDa intermediate. The activation of proMMP-2 by co-culture was also observed in other carcinoma cell lines, HSC-4 and SAS, but not in normal human keratinocytes. We characterized by in vitro invasion assay that A431 cells in co-culture preferentially invaded through Matrigel and the increased invasive activity was inhibited by exogenously adding tissue inhibitor of metalloproteinases 2. The augmented proMMP-2 activation by co-culture was achieved by the increase in membrane type 1-MMP (MT1-MMP) production along with that of its mRNA level. The predominant appearance of MT1-MMP was immunologically observed in A431 cells, but not human fibroblasts of the co-culture. Furthermore, epidermal growth factor (EGF) enhanced the co-culture-mediated proMMP-2 activation by increasing the production and gene expression of MT1-MMP, and thereby tumour invasive activity was further augmented. These results suggest that the cell-cell contact between carcinoma cells and normal fibroblasts enhances the production of MT1-MMP followed by sequential activation of proMMP-2 on the tumour cell surface, which may be closely implicated in tumour invasion in vivo.
基质金属蛋白酶2（MMP-2）/明胶酶A在肿瘤侵袭和转移中起重要作用。由于MMP-2以无活性形式（前MMP-2）从肿瘤细胞和邻近的基质细胞中分泌，因此激活过程对于表达降解细胞外基质成分的酶活性是必需的。我们在此报告，在与人正常皮肤成纤维细胞共培养的人鳞状癌细胞中诱导了前MMP-2的激活。当A431细胞与人类成纤维细胞以不同细胞比例共培养时，72 kDa的前MMP-2通过64 kDa中间体的出现转化为62 kDa的活性形式。在其他癌细胞系HSC-4和SAS中也观察到共培养对前MMP-2的激活，但在正常人角质形成细胞中未观察到。我们通过体外侵袭试验表征，共培养中的A431细胞优先通过基质胶侵袭，并且外源性添加金属蛋白酶组织抑制剂2可抑制增加的侵袭活性。共培养增强的前MMP-2激活是通过膜型1-MMP（MT1-MMP）产量及其mRNA水平的增加实现的。MT1-MMP主要出现在A431细胞中，而不是共培养的人类成纤维细胞中。此外，表皮生长因子（EGF）通过增加MT1-MMP的产量和基因表达来增强共培养介导的前MMP-2激活，从而进一步增强肿瘤侵袭活性。这些结果表明，癌细胞与正常成纤维细胞之间的细胞间接触增强了MT1-MMP的产生，随后在肿瘤细胞表面依次激活前MMP-2，这可能与体内肿瘤侵袭密切相关。
