*2.5. Cells Proliferation Assay*

The MTS cell proliferation assay (CellTiter 96® AQueous One Solution Cell Proliferation Assay, Promega) was used to determine metabolic activity in CaCo-2, CoLo-205 cell lines. Briefly, cells were seeded into 96-well plates at a density of 2 <sup>×</sup> <sup>10</sup><sup>3</sup> cells/well. After 24 h, the cells were treated with free drug (5-FU), empty LPs, 5-FU/LPs and anti-FZD10/5-FU/LPs, at 5-FU concentrations ranging from 1 µmol to 10 µmol (5-50 µM, in terms of total lipid concentration for the liposomal formulations), for 24, 48 or 72 h. After cell incubation with the different samples, cells were treated with the MTS tetrazolium compound for three additional hours and the absorbance was measured at a wavelength of 490 nm using a Perkin Elmer Victor Plate Reader (Mechelen, Belgium).
