Impact of spheroid culture on molecular and functional characteristics of bladder cancer cell lines.

The three-dimensional cell culture system is an increasingly important technique for discovering new biological aspects of cancer cells. In the present study it was demonstrated that bladder cancer cell lines, RT4 and 5637, spontaneously formed round multicellular spheroids (MCSs) in suspension by the aggregation method. MCSs consisted of cells differentially expressing luminal/basal markers. Western blotting showed that PPARγ and forkhead box A1 (FOXA1)of luminal markers were expressed to a lesser extent in MCSs than in parental cells grown in two-dimensional (2D) adherent culture. Cells in MCSs in suspension proliferated less efficiently, and were more resistant to cisplatin (CDDP) and gemcitabine than parental cells grown in 2D culture. Culturing cell lines as MCSs in suspension is a notable platform to decipher alternative biological aspects of bladder cancer cells, which could not be unraveled by the conventional 2D adherent culture.