Fig. 2

Overexpressed OPNc in secreted forms significantly reduced the sensitivity to 5-FU in both HT115 and HCT-8 cells. Rate of apoptosis in HT115 (a) and HCT-8 (b) cells transfected with OPN-SIs following 5-FU (20 μg/ml) treatments for 24 h as determined by flow cytometry. c, d Survival of transfected cells following 5-FU treatments (0, 1, 5, 10, 20 and 40 μg/ml for 48 h) as determined by CCK8 assays. e, f Cells cultured in conditioned medium (CM) from of OPN-SIs overexpressed cells and treated with 20 μg/ml 5-FU for 24 h for apoptosis assays. Cell survival in HT115 (g) and HCT-8 (h) subjected to dose-dependent response of 5-FU in OPN-SIs CMs. i, j Apoptosis assays using CMs with addition of 20 μg/ml OPN-neutralizing antibody. Data were represented as the mean ± SD from 3 (apoptosis) or 6 (viability) independent experiments. *p < 0.05, **p < 0.01, ***p < 0.001