Knockdown of miR-21 restores the expression of SMAD7 and MSH2 in MCF-7 and Hs578T breast cancer cell lines.

<p>MCF-7 and Hs578T cells were transfected with miR-21 inhibitor and a negative mock control using the Lipofectamine 2000 kit (Invitrogen). After 48 hrs, miR-21 expression level was knocked down by ∼10 fold as compared to the mock controls in both MCF-7 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054213#pone-0054213-g006" target="_blank">Fig. 6A</a>) and Hs578T (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054213#pone-0054213-g006" target="_blank">Fig. 6B</a>) cell lines using the Invitrogen SYBR green qRT-PCR kit. Untransfected cells were also included in the analysis (WT). With down-regulated miR-21 in both MCF-7 and Hs578T cells, MSH2 and SMAD7 mRNA expression was up-regulated by ∼1.67 and ∼3.6 fold, respectively (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054213#pone-0054213-g006" target="_blank">Fig. 6A and 6B</a>), while the protein level was increased by ∼35–43% for MSH2 and ∼80–133% for SMAD7 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054213#pone-0054213-g006" target="_blank">Fig. 6C</a>).