Effect of MiR-21 on Proliferation, Apoptosis and Invasion of Gastric Cancer Cells by Targeting PTEN / 胃肠病学

ABSTRACT

Background: Gastric cancer is a common gastrointestinal malignant tumor. MiR-21 can regulate the expression of phosphatase and tensin homologue (PTEN) protein and induce apoptosis of various tumor cells. Aims: To explore effect of miR-21 on proliferation, apoptosis and invasion of gastric cancer cells by targeting PTEN. Methods: SGC-7901 cells in logarithmic growth phase were divided into miR-21 mimic group, miR-21 inhibitor group, negative control group and blank control group. RT-PCR and Western blotting were used to detect mRNA and protein expressions of miR-21 and PTEN, respectively. The luciferase reporter gene assay was used to validate the targeted regulatory relationship between miR-21 and PTEN. Gastric cancer SGC-7901 cells were divided into blank control group, NC group, miR-21 group, PTEN group and miR-21+PTEN group. The proliferation activity was determined by CCK-8 assay, apoptosis was detected by TUNEL assay, and invasion and migration ability of cells was detected by Transwell and scratch test, respectively. The expressions of Ki-67, PCNA, ratio of cleaved caspase-3, Bcl-2, Bax, PTEN, p-PI3K/PI3K and p-Akt/Akt proteins were detected by Western blotting. A tumorigenesis model of nude mice was established to detect the effect of overexpression of miR-21 on the volume and mass of transplanted tumor. Results: MiR-21 could negatively regulate expression of PTEN. Compared with NC group, cell proliferation, invasion and migration rates were significantly increased in miR-21 group (P<0.05), apoptosis rate was significantly decreased (P<0.05), expressions of Ki-67, PCNA, ratio of Bcl-2/Bax, p-PI3K/PI3K and p-Akt/Akt proteins were significantly increased (P<0.05), expressions of PTEN and cleaved caspase-3 was significantly decreased (P<0.05). Cell proliferation, invasion and migration rates were significantly decreased in PTEN group (P<0.05), apoptosis rate was significantly increased (P<0.05), expressions of Ki-67, PCNA, ratio of Bcl-2/Bax, p-PI3K/PI3K and p-Akt/Akt proteins were significantly decreased (P<0.05), expressions of PTEN and cleaved caspase-3 were significantly increased (P<0.05). Compared with PTEN group, cell proliferation, invasion and migration rates were significantly increased in miR-21+PTEN group (P<0.05), apoptosis rate was significantly decreased (P<0.05), expressions of Ki-67, PCNA, ratio of Bcl-2/Bax, p-PI3K/PI3K and p-Akt/Akt proteins were significantly increased (P<0.05), and expressions of PTEN and cleaved caspase-3 were significantly decreased (P<0.05). Compared with the control group, overexpression of miR-21 significantly increased the volume and mass of transplanted tumor in nude mice (P<0.05). Conclusions: MiR-21 can negatively regulate PTEN expression, activate PI3K/Akt signaling pathway, promote proliferation, invasion and migration of gastric cancer cells, and inhibit cell apoptosis.