Figure 3.

Stem‐like ECE1c^K6R cells display enhanced drug resistance. (A) DLD‐1 cells expressing either Flag‐tagged ECE1c^WT or ECE1c^K6R proteins (or Mock cells) were analyzed for cell viability using MTS assay following incubation with 25 μm 5‐FU for 48 h. (B) As in A, 10⁶ cells were grown under normal conditions for 48 h and further analyzed for mRNA levels of P‐Glycoprotein, ABCC1, and ABCG2 by RT‐qPCR. (C) As in A, 10⁶ cells were incubated in the presence or absence of 200 μm verapamil for 30 min and incubated with 5 μL DCV for another 30 min. Side population abundance was determined by flow cytometry. Data represent average ± SEM (n = 3). ANOVA and Tukey tests were used. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001.