Figure 2.

ATRA induces MMP-2 secretion in time- and dose-dependent manners. THP-1 cells were treated with different concentrations of ATRA indicated above (a, d, and f) or with 1 μM ATRA for different time periods indicated above (b, e, and g). The culture supernatants were collected, concentrated by filtration, and subjected to western blot analysis (a and b). The culture supernatants were subjected to ELISA (f and g). Densitometry analysis of MMP-2 bands shown in (a and b) was performed by ChemiDoc MP System (d and e). A representative gel zymogram shows enhanced MMP-2 activity in ATRA-treated cells (c). ∗P < 0.01 versus DMSO-treated control.