The effects of Quercetin on miRNA-21 expression in MCF-7 cells

Cancer prevention, by the use of natural dietary or secondary metabolites in plants is one of the strategies has been attracting some of the scientific interests. One of these natural agents is Quercetin, which has anti-metastatic and anti-cancer effects. MiR-21 among different miRNAs is one of the most important frequently up-regulated miRs in numerous cancers including breast and increase cell proliferation and decrease apoptosis and therefore leads to increases in cancer incidence. We assessed the effects of Quercetin on cell viability, MiR-21, Maspin and PTEN gene expression in the MCF-7 cell line. The human MCF-7 breast cancer cell line was cultured in RPMI1640 and treated with different concentrations of Quercetin (0.01-100 μM) for 24 hours. The cytotoxic effect of Quercetin on MCF-7 viability was determined using Methyl-Thiazolyl-Tetrazolium (MTT) assay by IC50 determination. The relative expression of MiR-21, Maspin, and PTEN gene expression were determined by real-time Polymerase Chain Reaction (PCR). The maximum inhibitory effect of Quercetin on cell viability was observed at 100 μM after 24-hour incubation. The expression of MiR-21 in the treated cells compared to controls was significantly decreased after treatment with three different concentrations of Quercetin. In addition, expression of Maspin and PTEN in the treated cells compared to controls was significantly increased. Quercetin decreases cell viability and miR-21 gene expression in a dose-dependent manner. Also, Quercetin decreases mir-21 gene expression and increases Maspin and PTEN expression in MCF-7 breast cancer cell line. The growth inhibitory properties and therapeutic effect of Quercetin on the breast cancer may be mediated by reduction of miR-21 expression, and for verifying this hypothesis and the possible therapeutic implication of Quercetin in this direction further studies are necessary.