NDRG2 Inhibits Migration of Breast Cancer Cells Through Upregulating PTEN Expression

Objective To investigate the effects of N-Myc downstream regulated gene 2 (NDRG2) on the migration of human breast cancer cells by using two parallel cell lines MCF-7 and LM-MCF with different metastatic abilities.

Methods The expression level of NDRG2 and PTEN in breast cancer cells were detected by RT-PCR and Western blot. The effects of overexpressed or down-regulated NDRG2 on the migration of breast cancer cells were investigated by Transwell migration test. The regulation mechanism between NDRG2 and PTEN on cell migration was detected via co-transfecting breast cancer cells with pCMV-NDRG2 and PTEN siRNA (or NDRG2 siRNA and pCMV-PTEN).

Results The mRNA and protein expression levels of NDRG2 and PTEN in MCF-7 cells were higher than those in LM-MCF-7/MDA-MB-231 cells (P < 0.05). Overexpressed NDRG2 via transfecting LM-MCF-7 and MDA-MB-231 cells with pCMV-NDRG2 could inhibit cell migration ability to 13.02% and 26.33%(P < 0.01) respectively. Downregulated NDRG2 expression in MCF-7 cells could enhance cell migration ability to 354.62%(P < 0.01). Interestingly, the

Results of Western blot and Transwell assay revealed that the downregulation of NDRG2 expression resulted in the downregulation of PTEN expression. Co-transfecting LM-MCF-7/MDA-MB-231(or MCF-7) cells with pCMV-NDRG2/PETN siRNA (or pCMV-PTEN/NDRG2 siRNA), the migration ability of cells had no significant changes (P > 0.05).

Conclusion The downregulation of the expression of NDRG2 could inhibit the expression of PTEN, which lead to the losing control of the migration of breast cancer cells. Downregulating NDRG2/PTEN pathway is a significant mechanism for breast cancer cells acquiring high migration ability.