uPA and PAI-1 levels. (A) Average uPA levels (ng/mL) in the supernatant of each of the 3 categories of AML cell lines as determined by ELISA are shown. Nonsensitive cell lines (black) had the highest concentrations of total uPA in their supernatants, which indicates that DTU2GMCSF efficacy is determined by uPAR expression levels rather than uPA concentration. Cell lines that were sensitive to DTU2GMCSF only when exogenous pro-uPA was added (gray) had significantly lower total uPA levels in their supernatants as compared to cells that did not require the addition of exogenous pro-uPA (white; P = .04). (B) Total PAI-1 concentrations in the supernatants of the AML cell lines as determined by ELISA are shown. PAI-1 levels did not correlate with DTU2GMCSF efficacy.