VEGF-C and mutant VEGF-C promote leukemic cell proliferation.

(A) THP-1 leukemic cells were serum-starved for 48 hours and then left untreated or incubated in the presence of increasing concentrations of VEGF-C (20, 100, and 200 ng/mL), and total live cells were counted by trypan blue exclusion. (B) HEL leukemic cells were serum-starved for 48 hours, same as above, in the absence or presence of VEGF (20 ng/mL), VEGF-C (100 ng/mL), or mutVEGF-C (200 ng/mL), and total live cells were counted by trypan blue exclusion. (C) Primary leukemias (a total of 6, as described in “Materials and methods”) were cultured in serum-free conditions for 48 hours, in the presence or absence of VEGF-C (100 ng/mL) or mutVEGF-C (200 ng/mL). The total number of viable cells was determined by trypan blue exclusion. *VEGF-C and mutVEGF-C induced a significant increase in viable cells (P < .05 compared with untreated cells).