Fig. 5

Effect of verapamil on paclitaxel (PTX) toxicity and PTX uptake/release by human amniotic mesenchymal stromal cells (hAMSCs). a P-glycoprotein (P-gp) expression is represented as the ratio of mean fluorescence intensity (MFI) for each donor: nd not determined. b Proliferation of hAMSCs in the presence of PTX and 20 μM verapamil (VP). Half maximal inhibitory concentration (IC₅₀) values (mean ± SD) were calculated by linear regression analysis. c Proliferation curves of CFPAC-1 in the presence of serial dilutions of PTX (white circles), conditioned media from PTX-primed hAMSCs (hAMSCsPTX-CM) (black circles) or hAMSCsPTX-CM collected from cells primed with PTX in the presence of 20 μM VP (black triangles). d Proliferation curves of CFPAC-1 in the presence of serial dilutions of hAMSCsPTX-CM (solid line) or hAMSCsPTX-LYS (dashed line) from PTX primed hAMSCs. Both CM and LYS were obtained from hAMSCs primed with PTX in the presence of 20 μM VP. e Amount of PTX incorporated and released by hAMSCs (CM) and the amount incorporated and retained inside the cells (LYS), expressed as percentages of the total incorporated PTX, considered 100 %. hAMSCs were primed in the presence of 20 μM VP. Bars represent the mean values ± SD. The difference between CM and LYS was not statistically significant (p >0.05). To evaluate the effect of VP, hAMSCs from two donors were used