Figure 2. Neuropilin-2 promotes cell proliferation in colon carcinoma cell lines.

Transfected cells were analyzed for NRP1 and NRP2 expression by flow cytometry analysis (A) or by western blotting (B). For flow cytometry analysis, Relative Fluorescence Intensity (RFI) was calculated. Caki1 and HUVEC cells were used as positive control for NRP1 and NRP2 staining respectively. C, Proliferation of HT29 and Colo320 cells, according to NRP2 expression was assessed using MTT assays. 4000 cells were let in culture during 24, 48 or 72h before analysis. NRP2 expression is associated with an enhanced proliferation in colon cancer cells. Data represent means of triplicates plus or minus the standard error (SE) of a representative experiment out of three performed. (**, P<0.01). D, Similar MTT experiments were reproduced in the presence of bevacizumab (0.25 and 1 mg/mL, 72 h). HMEC-1 microvascular endothelial cells were used as a positive control for the bioactivity of bevacizumab. Indeed, bevacizumab significantly decreases HMEC-1 proliferation whereas no decrease of cell proliferation is observed with HT29^NRP2 and Colo320 cancer cells. Experience was made 3 times, and for each time in triplicates. E, Flow cytometric analysis of DNA content of transfected colon cancer cells. NRP2 expression is associated with an enhanced number of cells in phase S. Data represent results of a representative experiment out of 3 expressed as the mean of duplicate assays (*, P<0.05; **, P<0.01, ***P<0.001).