Biological and Pharmaceutical Bulletin
Online ISSN : 1347-5215
Print ISSN : 0918-6158
ISSN-L : 0918-6158
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Adhesive Defect in Extracellular Matrix Tenascin-X-Null Fibroblasts: A Possible Mechanism of Tumor Invasion
Takeharu MinamitaniHiroyoshi ArigaKen-ichi Matsumoto
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2002 Volume 25 Issue 11 Pages 1472-1475

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Abstract

Extracellular matrix tenascin-X (TNX)-null mice, generated by disruption of the Tnx gene, display augmented invasion and metastasis of B16-BL6 melanoma tumor cells due to increased activities of matrix metalloproteinase (MMP)-2 and MMP-9. In this study, we investigated cell–matrix and cell–cell adhesions using TNX-null fibroblasts and wild-type fibroblasts. TNX-null fibroblasts exhibited a decreased attachment to fibronectin compared with that of wild-type fibroblasts. B16 melanoma cells were cocultured with wild-type or TNX-null fibroblasts, and the adhesion of B16 melanoma to the fibroblasts was assessed. B16 melanoma cells on wild-type fibroblasts proliferated and spread out in a horizontal direction, whereas those on TNX-null fibroblasts overlapped each other rather than migrating horizontally. These overlapping B16 melanoma cells on TNX-null fibroblasts peeled off faster than those on wild-type fibroblasts. To determine whether the decreased cell–matrix and cell–cell adhesions on TNX-null fibroblasts were due to increased MMP activity, the activities of MMPs in wild-type and TNX-null fibroblasts were compared by gelatinolytic assays. The analysis of MMPs from conditioned media demonstrated that almost the same levels of MMP activities were detected between wild-type and TNX-null fibroblasts. However, contrary to our expectations the activities of MMPs from conditioned media of B16 melanoma cells cocultured on TNX-null fibroblasts were rather reduced than those of B16 melanoma cells cocultured on wild-type. We concluded that the absence of TNX in the extracellular environment might play an important role in enhancement of the detachment of B16 melanoma cells.

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© 2002 The Pharmaceutical Society of Japan
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