Relation Between Laminin-5 γ2 Chain and Cell Surface Metalloproteinase MT1-MMP in Clear Cell Carcinoma of the Ovary

Ovarian clear cell carcinoma (CCC) characteristically shows stromal accumulation of the basement membrane material laminin-5 (LN-5). LN-5 works not only as a substrate for cell anchorage but also its a stimulator for cell migration. Our previous Study showed that CCC cell increased migration over excessive LN-5 in vitro. However, it remains unclear wily LN-5 rather promotes cell migration than cell anchorage. A recent Study has shown that the processing of the LN-5 gamma 2 chain by membrane type matrix metalloproteinase (MT1-MMP) was responsible for increasing cell migration activity but reducing cell anchoring activity of LN-5. In the present study, 3 CCC cell lilies were examined for LN-5 gamma 2 chain levels by Western blotting. Processed gamma 2 chain (105 kDa) Was detected in the extracellular matrix of all 3 CCC cell lines in vitro. Immunocytochemically they expressed MT1-MMP oil the cell Surface. In Surgical specimens, 22 of 30 (73%) CCCs showed membranous expression of MT1-MMP, and stromal accumulation of the LN-5 gamma 2 chain, especially in the area of papillary architecture. These results indicate that proteolytic processing of the LN-5 gamma 2 chain by MTI-MMP is involved in cell migration and subsequent architectural organization in ovarian CCC.