To investigate the effects of long non-coding RNA (lncRNA) MAGI1-IT1 on the proliferation, invasion, migration and epithelial mesenchymal transformation (EMT) of breast cancer cells by regulating the miR-485-5p/actin gamma 1 (ACTG1) axis.

HCC1937 cells were cultured in vitro and randomly divided into control, si-MAGI1-IT1, miR-485-5p mimics, negative cotransfection and positive cotransfection groups. Control group was cultured normally without transfection; si-MAGI1-IT1 group was transfected with si-MAGI1-IT1; miR-485-5p mimics group was transfected with miR-485-5p mimics; negative cotransfection group was transfected with si-NC and NC-miR-485-5p; positive cotransfection group was given si-MAGI1-IT1 and miR-485-5p inhibitor combined transfection. Cell proliferation was detected by cell counting kit-8 method, cell migration was detected by cell scratch assay, cell invasion was detected by Transwell assay, and expression levels of lncRNA MAGI1-IT1, miR-485-5p and ACTG1 were detected by real-time fluorescence quantitative polymerase chain reaction method. The expression of proliferation and EMT-related proteins were detected by immunohistochemical staining.

The cell activities (optical density) of the control, si-MAGI1-IT1, miR-485-5p mimics, negative cotransfection and positive cotransfection groups were 0.89±0.12, 0.36±0.05, 0.32±0.03, 0.89±0.10 and 0.85±0.11; the migration rates were (91.82±11.13)%, (38.40±7.64)%, (33.17±6.03)%, (92.43±10.87)% and (86.10±10.76)%; the number of invasions was 296.50±23.48, 93.00±17.36, 76.50±15.01, 302.50±25.32 and 269.00±24.92; the relative expression levels of lncRNA MAGI1-IT1 were 0.98±0.11, 0.29±0.06, 0.96±0.10, 1.00±0.12 and 0.30±0.07; the relative expression levels of miR-485-5p were 0.99±0.13, 2.12±0.16, 2.20±0.18, 0.98±0.15 and 1.04±0.16; the relative expression levels of ACTG1 were 1.01±0.12, 0.34±0.05, 0.31±0.07, 1.02±0.14 and 0.97±0.11; the positive expression levels of proliferating cell nuclear antigen (optical density) were 1.65±0.16, 0.53±0.12, 0.45±0.08, 1.64±0.14 and 1.60±0.17; the positive expression levels of Cyclin D1 (optical density) were 1.53±0.15, 0.46±0.11, 0.40±0.06, 1.52±0.14 and 1.48±0.13; the positive expression levels of Vimentin (optical density) were 1.49±0.14, 0.45±0.07, 0.39±0.06, 1.50±0.12 and 1.45±0.13, respectively. The above indexes in the si-MAGI1-IT1 group were compared with the control group, the above indexes in the miR-485-5p mimics group (except lncRNA MAGI1-IT1) were compared with the control group, the above indexes in the positive cotransfection group (except lncRNA MAGI1-IT1) were compared with the si-MAGI1-IT1 group, the differences were statistically significant (all P<0.05).

Knockdown of lncRNA MAGI1-IT1 can reduce the expression of ACTG1 by up-regulating miR-485-5p, thereby inhibiting the proliferation, migration, invasion and EMT of breast cancer cells.