Objective  To explore the influence of pulsatilla saponin on proliferation, migration and invasion of gastric cancer HGC-27 cells and its possible mechanism.

Methods  Human gastric cancer HGC-27 cells were treated with different doses of pulsatilla saponin (12.5, 25.0, 50.0 μmol/L) and named as low-dose pulsatilla saponin group, medium-dose pulsatilla saponin group and high-dose pulsatilla saponin group, and the normal cultured HGC-27 cells were named as control group. The si-NC, si-circNRIP1, pcDNA and pcDNA-circNRIP1 were transfected into HGC-27 cells, and were named as si-NC group, si-circNRIP1 group, pcDNA group and pcDNA-circNRIP1 group respectively. HGC-27 cells were transfected with pcDNA and pcDNA-circNRIP1 and cultured with 50.0 μmol/L pulsatilla saponin, and were named as pulsatilla saponin plus pcDNA group and pulsatilla saponin plus pcDNA-circNRIP1 group respectively. CCK-8 assay, colony formation assay and Transwell assay were used to detect the proliferation, clone formation and migration, and invasion respectively; quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of circular RNA nuclear receptor interacting protein 1 (circNRIP1); Western blot was used to detect the expressions of E-cadherin and N-cadherin proteins.

Results  In the control group, low-dose pulsatilla saponin group, medium-dose pulsatilla saponin group and high-dose pulsatilla saponin group, the inhibition rates of cell proliferation and the levels of E-cadherin protein significantly increased gradually, the number of cell clone formation, migration and invasion significantly decreased gradually, and the expressions of N-cadherin protein and circNRIP1 significantly decreased gradually (P < 0.05); the expression level of circNRIP1 in the pcDNA-circNRIP1 group was significantly higher than that in the pcDNA group, while the expression level of circNRIP1 in the si-circNRIP1 group was significantly lower than thatin the si-NC group (P < 0.05); the inhibition rate of cell proliferation and level of E-cadherin protein in the si-circNRIP1 group were significantly higher than those in the si-NC group, while the level of N-cadherin protein and the number of cell clone formation, migration and invasion were significantly lower than those in the si-NC group (P < 0.05); the inhibition rate of cell proliferation and level of E-cadherin protein in the pulsatilla saponin plus pcDNA-circNRIP1 group were significantly lower than those in the pulsatilla saponin plus pcDNA group, while the level of N-cadherin protein and the number of cell clone formation, migration and invasion were significantly higher than those in the pulsatilla saponin plus pcDNA group (P < 0.05).

Conclusion  Pulsatilla saponin can inhibit the proliferation, migration and invasion of gastric cancer cells in a dose-dependent manner, and its mechanism may be associated with down-regulation of circNRIP1 expression.