Spheroids/colonospheres-derived cells show increased dye-efflux. A. Photomicrographs showing exclusion of Hoechst-33342 (H342) by HCT-116 colonospheres-derived cells in the absence or presence of verapamil, an inhibitor of membrane ABCG2 transporter protein (positive control). Propidium Iodide was used to detect dead cells. B. The quantitaion of flow cytometry analysis of H342 dye exclusion by HCT-116 parental and colonospheres-derived cells. C. Western blot showing changes in the levels of ABCG-2 in HT-29 and HCT-116 wt parental (P) and colonospheres-derived cells (S). The numbers represent percent of corresponding control normalized to β-actin. *p < 0.01 compared to the corresponding parental cells.