Objective To investigate the effects and mechanism of microRNA-1291(miR-1291) on the cell proliferation, migration and invasion of gastric cancer cells.

Methods The public database was used to analyze the expression of miR-1291 in gastric cancer and normal gastric tissues. Human gastric cancer SGC-7901 cells and human gastric mucosal epithelial cells GES-1 cells were selected, and the levels of miR-1291 expression were compared. The miR-1291 mimic, miR-NC, miR-1291 inhibitor and miR inhibitor plasmids were transfected into SGC-7901 cells, and these cells were divided into miR-1291 group, miR-NC group, miR-1291inhibitor group, miR inhibitor group. BMP activator membrane-bound inhibitor (BAMBI) mimic plasmid, Vector plasmid, sh-BAMBI plasmid, and sh-NC plasmid were transfected into cells, and were set as BAMBI group, Vector group, sh-BAMBI group, and sh-NC group. CCK-8 assay was applied to detect cell proliferation ability; transwell assays were applied to detect cell invasion and migration ability; quantitative real-time fluorescence polymerase chain reaction (qRT-PCR) was applied to detect miR-1291 and BAMBI mRNA levels; Western blot was applied to detect BAMBI, transforming growth factor β (TGF-β) and SMAD homolog 4 (SMAD4) protein levels; dual luciferase reporter gene assay was applied to detect the targeting relationship between miR-1291 and BAMBI.

Results The expression level of miR-1291 in gastric cancer tissues was (0.85±0.11), which was lower than (2.02±0.23) in normal gastric tissues (t=18.33, P < 0.001). The expression level of miR-1291 in SGC-7901 cells was lower than that in GES-1 cells, and the levels of BAMBI protein and BAMBI mRNA were higher than that in GES-1 cells (P < 0.01). The optical density (OD) value, invasion and migration cell numbers in the miR-1291 group at 72 h were lower or less than those in the miR-NC group, and miR-1291 inhibitor group had higher or more OD value, and the number of invasion and migration cells at 72 h than miR inhibitor group (P < 0.01). The OD value and the number of invasion and migration cells at 72 h were higher or more in the BAMBI group than Vector group, and were lower or less in the sh-BAMBI group than those in the sh-NC group (P < 0.01). The expression levels of BAMBI protein and BAMBI mRNA in cells of miR-1291 group were lower than those of miR-NC group, while the expression levels of BAMBI protein and BAMBI mRNA in cells of miR-1291 inhibitor group were higher than those of miR inhibitor group (P < 0.01). The results of double luciferase reporter gene experiment showed that miR-1291 had a targeting relationship with BAMBI. The protein levels of TGF-β and SMAD4 in BAMBI group were lower than those in the Vector group, and the protein levels of TGF-β and SMAD4 in sh-BAMBI group were higher than those in the sh-NC group, the difference was statistically significant (P < 0.01).

Conclusion MiR-1291 can inhibit the proliferation, migration and invasion ability of gastric cancer cells, and the mechanism may be related to the upregulation of BAMBI expression, thereby inhibiting TGF-β pathway.