Effect of miR-101 on proliferation and oxidative stress-induced apoptosis of breast cancer cells via Nrf2 signaling pathway.

OBJECTIVE: To explore the influence of micro ribonucleic acid (miR)-101 on breast cancer cell proliferation and apoptosis via nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling pathway. MATERIALS AND METHODS: All MCF-7 cells were divided into 3 groups, namely control group, miR-101 mimic group (the cells were treated with 50 nmol/L miR-101 mimic), and miR-101 inhibitor group (the cells were treated with 50 nmol/L miR-101 inhibitor). The impact of miR-101 expression level on MCF-7 cell proliferation was evaluated via cell counting kit-8 (CCK-8) and colony formation assays. After the MCF-7 cells in the three groups were treated with 100 nM H2O2 for 12 h, the change in the apoptosis rate was detected via flow cytometry. Moreover, the influence of miR-101 expression level on the Nrf2 signaling pathway was detected via reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. RESULTS: According to the CCK-8 assay results, compared with that in control group, the proliferation rate of cells notably declined at 48, 72, and 96 h in miR-101 mimic group, and the difference was statistically significant (p<0.01), while it was substantially raised in miR-101 inhibitor group, showing a statistically significant difference (p<0.01). Compared that in control group, the cell colony formation rate was remarkably lowered in miR-101 mimic group, and the difference was statistically significant (p<0.01), while it was substantially raised in miR-101 inhibitor group (p<0.01). According to the flow cytometry assay results, compared with that in control group, the apoptosis of MCF-7 cells was markedly enhanced in miR-101 mimic group, showing a statistically significant difference (p<0.01), while it was weakened in miR-101 inhibitor group, with a statistically significant difference (p<0.01). The influence of miR-101 on the expression level of Nrf2 was detected via RT-PCR, and it was found that the messenger RNA (mRNA) expression level of Nrf2 was notably lower in miR-101 mimic group than that in control group (p<0.01), while it was raised in miR-101 inhibitor group. Western blotting results showed that compared with control group, miR-101 mimic group had a substantially lowered protein expression level of Nrf2 in the cell nucleus, with a statistically significant difference (p<0.01), while it was notably raised in miR-101 inhibitor group and the difference was statistically significant (p<0.01), indicating that miR-101 can remarkably lower the nucleoprotein expression level of Nrf2. CONCLUSIONS: The results of this study imply that miR-101 can inhibit the expression of Nrf2 to suppress the proliferation of breast cancer cells and enhance their sensitivity to oxidative stress, which provides a theoretical basis for reversal of tumor resistance.