3.5. Cell proliferation activity of cp-hFGF7115-114
The biological function of hFGF7 can also be proven by the controlling process for repairing epithelial cells in-vitro ; therefore, we further tested whether cp-hFGF7115-114 could induce the proliferation of NIH3T3 cells. A cell proliferation assay for time course analyses was conducted at 1, 10, and 50 ng/mL cp-hFGF7115-114 concentrations by using purified proteins. As shown in Figure 4C, cp-hFGF7115-114retained a cell proliferation activity similar to that of the wild type hFGF7 under the same concentrations and incubation times. We also measured the cellular toxicity of cp-hFGF7115-114 by using NIH3T3 cells. To do so, the cells were treated with cp-hFGF7115-114 for 24 and 72 h at concentrations of 0.5, 1, 10, 50, and 100 ng/mL. The commercially available hFGF7 was also used as the control. As a result, a survival rate of 98 to 100% was shown in the case of the purified cp-hFGF7115-114 when the cells were treated for 24 h at a concentration of 50 ng/mL. At the 72 h culture time point, the cell viability did not decrease to 95% or less even with the purified protein at a concentration of 100 ng/mL (Figure S4). These results confirmed that the purified cp-hFGF7115-114 did not cause more cytotoxicity than the wild type, and thus we were unable to observe a distinct difference between the two proteins.