Figure 4.

KLF8 upregulated expression of miR-146a is responsible for the induction of stem cell traits in MCF-10A cells. A and B: Inhibition of miR-146a suppresses the KLF8-dependent expression of ALDH and mammosphere formation. The 10A-iK8 cells were transfected with a Cy3 dye-labeled miR-146a inhibitor or an inhibitor control. After 3 days, the expression of KLF8 was induced in the cells and the cells were cultured for 7-10 days either in regular culture plates for analysis of ALDH⁺ population (% shown in red) by FACS in the absence or presence of the ALDH inhibitor DEAB (A) or in mammosphere culture dishes for mammosphere formation (B). Representative FACS results and mammosphere images were shown in the left panels. C and D: Overexpression of miR-146a is sufficient to induce stem cell traits in MCF-10A cells. MCF-10A cells were infected with retroviral viruses expressing pre-miR-146a or pre-miR control and selected with G418. The cells were then used for analysis of ALDH⁺ population (% shown in red) by FACS (C) and mammosphere formation (D) similarly as described in A and B. The data represent the mean ± S.E. of at least three independent experiments in triplicate. *P < 0.05.