CD40 stimulates uPA secretion, which is blocked by PI3K and NF-κB inhibitors.

(A) Media from untreated (−) and CD40-activated (+) MM.1S cells cultured in serum-free medium for 12 hours were collected and concentrated as described in “Materials and methods.” Secretion of uPA was detected by Western blot analysis with an anti-uPA mAb. (B) Media from untreated or CD40-activated MM.1S cells, in the presence or absence of PI3K inhibitors (0.2 μM Wortmannin, Wort; 30 μM LY294002, LY), NF-κB inhibitors (10 μM PS1145; 1 μM SN50), or 5 μg/mL chx for 48 hours, were concentrated for assay of uPA secretion as described in “Materials and methods.”