Cytotoxic Drugs Screening in 3D Spheroids

After 48 h of spheroid formation, chemotherapeutic agents, namely fluorouracil combined with epirubicin and cyclophosphamide (FEC) and docetaxel combined with doxorubicin and cyclophosphamide (TAC) were administered to the spheroids in clinically relevant combinations at the peak plasma concentrations as described previously [26 (link)]. Galectin-1 was applied in a concentration of 30 μg/ml. Medium (untreated) and solvent controls were included in each experiment. Solvents used to control the effect of the drugs were 0.2%H2O plus 0.26 % NaCl for FEC therapy, 0.01 % H2O plus 0.21 % NaCl for TAC treatment and 0.15 % phosphate buffered saline (PBS) for galectin-1. Each treatment and control was performed in six replicates. The drugs were allowed to take effect for a total of 48 h. Chemotherapeutics were obtained from the pharmacy of the University Hospital LMU (Munich, Germany). Treatment efficacy was assessed using an ATP assay (CellTiter-Glo® Luminescence Cell Viability Assay, G8461, Promega, Germany) to quantify cell survival in vitro. Mean cell survival was expressed as percent of residual metabolic activity relative to the solvent controls.