Addition of recombinant u-PA attenuates the antiproliferative effect of PAI-2–expressing THP-1 cells.

The proliferation rate of THP-1 cells expressing wild-type PAI-2 (THP-1/PAI-2) was determined in the absence and in the presence of recombinant u-PA (0.01 and 0.1 mU/mL) as indicated (“+”). Addition of u-PA increased the proliferation rate of the PAI-2–expressing THP-1 cells. Cell number was determined after 5 days. THP-1/neo represents THP-1 cells transfected with pCI-neo. This experiment was performed in triplicate on 3 separate occasions.