Regulation of matrix metalloproteinase-2 (gelatinase A, MMP-2), membrane-type matrix matelloproteinase-1 (MT1-MMP) and tissue inhibitor of metalloproteinases-2 (TIMP-2) expression by elastin-derived peptides in human HT-1080fibrosarcoma cell line

Soluble kappa-elastin peptides were shown to stimulate the expression of MM P-2 (but not MMP-9) by human fibrosarcoma MT-1080 cells, both at the protei n and mRNA levels; maximal effect being observed at a concentration of 25 m u g/ml of kappa-elastin. The stimulatory effect could be reproduced using V al-Gly-Val-Ala-Pro-Gly (VGVAPG) peptide, an elastin-derived hydrophobic hex apeptide which represented the elastin receptor binding sequence of tropoel astin, Furthermore, treatment of cells with lactose (30 mM), which dissocia ted 67-kDa elastin binding protein (EBP) from cell surfaces, completely abo lished this effect, suggesting that the elastin receptor could mediate such a response, Using a specific monoclonal antibody, 67-kDa EBP was detected in MT-1080 membrane preparations by Western immunoblotting, Following treat ment with 25 mu g/ml kappa-elastin or 200 mu g/ml VGVAPG, increased levels of the active 62-KDa form of MMP-2 were found in HT-1080 cell extracts, Sti mulation of MT1-MMP mRNA expression by treatment with elastin-derived pepti des (EDPs) was shown by competitive polymerase chain reaction (PCR), A reve rse zymography analysis revealed that EDPs also stimulated TIMP-2 (but not TIMP-1) production by MT-1080 cells, Competitive PCR confirmed increased TI MP-2 mRNA expression by such treatment, These results suggest that occupanc y of the 67-kDa elastin receptor by elastin-derived peptides enhanced both expression and activation of proMMP-2 and consequently, could promote the i nvasive/metastatic ability of tumor cells expressing this receptor.