Figure 5. MESCs acquire the senescent phenotype in response to recombinant IGFBP3. (A) Quantitative assay of SA-β-Gal positive cells after treatment with 0.5 μg rIGFBP3 or CM old for 9 days, or 200 μM H2O2 for 1 h. Senescent cells were detected with SA-β-Gal staining kit. The results are presented as mean ± SD of three independent experiments, *p<0.01. (B) Analysis of the MCAM/CD146 expression levels. Quantitative assay of CD146 positive cells after treatment with 0.5 μg rIGFBP3 for 9 days or 200 μM H2O2 for 1 h. Mean values ± SD of three independent experiments are shown, *p<0.05. (C) rIGFBP3 internalization dynamics. Cells were stimulated with 0.5 μg rIGFBP3 for the indicated time, and then IGFBP3 expression levels were analyzed by immunoblotting in each time point. GAPDH was used as a loading control. Representative results of three independent experiments are shown. Ctr – untreated cells. Abbreviation: MCAM/CD146, the melanoma cell adhesion molecule.