Fig. 1

Chemo-resistant colon cancer cells exhibited increased cancer stem cell phenotypes. a Establishment of 5-FU resistant (designated as R) colon cancer cell lines. Both HCT116R and DLD-1R cells exhibited a significantly increased resistance against 5-FU as compared to their non-acclimatized counterparts. b Flow cytometric analysis of respectively. The CD44+ cell population cells were increased by approximately 12.4 and 21.8% in HCT-116 and DLD-1 cells respectively. c The percentage of SP cells in both cell lines were also increased, approximately 2.64% in HCT-116 and 4.31% in DLD-1, respectively. d Comparative tumor sphere formation essay. There was an average of 2.3-fold and 3.2-fold increase in the number of spheres (diameter ≥ 200 μm is considered as a sphere) formed in the HCT-116R and DLD-1R cells as compared to their naïve counterparts. e Comparative western blot analysis between the parental (P) and 5-FU acclimatized CRC cells. A significant increased expression in NF-kB, Notch1, WNT1 in the 5-FU acclimatized HCT-116 (R) and DLD-1 (R) cells. f Comparative real-time PCR analysis between parental colon cancer cells and their spheroid counterparts. Oncogenic markers, cMyc, cyclin D1 and stem cell associated markers, CD44, β-catenin and Axin-2 were all significantly up-regulated in the spheroids as compared to their parental counterparts. * p < 0.05. **p < 0.01