Figure 1. Specific siRNA mediated knockdown of CD133 within non-differentiated Caco-2 cells led to an increase in Tf intracellular accumulation but had no impact on Dx and CTB uptake.

A) Immunofluorescence associated flow cytometric analysis of CD133 expression on non-differentiated Caco-2 cells treated with 30 nM of control or CD133-specific siRNA. Results are expressed as a percentage of the control treatment, representing the geomean fluorescence intensity levels obtained after AC133 immunostaining of cells treated with irrelevant siRNA (CD133^high Caco-2 cells); note the effective down regulation of CD133 when CD133-specific siRNA (CD133^low Caco-2 cells) was used. B–D) Flow cytometric analysis of intracellular uptake of Dx-FITC (B), CTB-FITC (C) and Tf-Alexa 488 (D) within CD133^high and CD133^low Caco-2 cells after 1 h of incubation at 37°C/5%CO₂. Results are expressed as percentage of control, thus representing the geomean fluorescence intensity levels obtained for cells treated with vehicle alone. Data represented mean ± s.e.m. obtained from three independent experiments. Dunnett's test: **p<0.01, ***p<0.001