Figure 5. VentX promotes proinflammatory response and inhibits proliferation in U937 cells.

U937 cell lines were treated as described in Figure 4. (A) Phagocytosis of DOX-treated U937 cells at 37°C. Red histogram represent GFP-expressing cells; green histogram represent GFP.VentX-expressing cells. Filled blue histogram represents background staining of cells not undergoing phagocytosis. (B) Effects of VentX expression on the mRNA level of proinflammatory cytokines. U937 cells were treated with 1 μg/ml LPS for 6 hours after 72 hours exposure to DOX. Real-time PCR was performed to determine mRNA levels of the indicated cytokines. Data are presented as the fold of elevation and are mean + SD of triplicates from 1 representative experiment. (C) Secreted IL-1β and TNF-α from U937 cell culture supernatants were determined with ELISA kits. U.D., undetectable. Data represent mean + SD of triplicates from 1 representative experiment. (D) Effects of VentX on growth of U937 cells. Cells (2 × 10⁴) were seeded in 6-well plates and cultured for 5 days in the presence of 1.0 μg/ml DOX. Cell numbers at the indicated days were determined and plotted. (E) Cell cycle profiles of U937 cells expressing GFP or GFP.VentX after 3 days exposure to DOX. Cells were stained with PI and analyzed by FACS. (F) Effects of VentX on mRNA levels of c-Myc and p21 as determined by real-time PCR. Data represent mean + SD of triplicates from 1 representative experiment. *P < 0.05, **P < 0.01.