HMGB1 induced MMP-9 but not MMP-2 activation in WI-38 cells.

<p>Cells were treated with 1, 10, 100 ng/mL of HMGB1 for 18 h. (A). Cell culture medium was isolated for zymography. MMP-9 or -MMP-2 indicated active form of MMP-9 or MMP-2. (B). MMP-9 and MMP-2 expression was quantified by Image J software. (C). Cells were isolated for detection of MMP-9 mRNA expression by real-time PCR. (D). Cells were isolated for detection of MMP-9 protein expression by western blotting. (E). Protein expression was quantified by Image J software. Data are expressed as mean ± S.E.M. (n ≥ 3) *<i>p</i><0.05, **<i>p</i><0.01, ***<i>p</i><0.001 as compared with negative control (NC) group, in which the cells were treated with PBS.