| Claudin 1 siRNA largely suppressed the invasion of OSC 4 and decreased the activation of MMP 2 , the expression of membrane type MMP 1 ( MT 1 MMP ) , and the cleavage of laminin 5 gamma 2 . ^^^ These results suggest that claudin 1 up regulates cancer cell invasion activity through activation of MT 1 MMP and MMP 2 , which results in enhanced cleavage of laminin 5 gamma 2 chains . . ^^^ |