Figure 2. The TRAP-Fc inhibits proliferation of human tumor cells.

(A) BxPC3 pancreatic tumor cells (2×10⁴) were incubated with increasing concentrations of TRAP-Fc. Cell proliferation was determined in hexaplicates after 5 days, using the MTT assay. Averages ± S.D. (bars) are indicated. (B) The indicated cancer cells (2×10⁴) were incubated for 5 days with TRAP-Fc (20 μg/ml) and cell proliferation was determined as in A. (C) H1437 lung tumor cells, PC3 prostate tumor cells and BxPC3 pancreatic tumor cells (each at 2×10⁴ cells per well) were incubated with the indicated ligands (5 ng/ml), along with TRAP-Fc (20 μg/ml), and cell proliferation assayed as in A. (D and E) H1437 cells were seeded in agarose (top layer: 0.3% agar; bottom layer: 0.6% agar) in 6-well plates (1×10⁴ cells per well) and overlaid with medium. TRAP-Fc was added to both the soft agar and to the medium (at 100 μg/ml). Photographs were captured and colony numbers were determined in five randomly chosen high-powered fields. The data represent mean±S.D. The data sets were analyzed for statistically significant differences by using the two-tailed Student t test.