MicroRNA-34a inhibits tumor invasion and metastasis in gastric cancer by targeting Tgif2.

To study how miR-34a acts as a tumor suppressor in inhibiting the invasion and metastasis of the gastric cancer cells. First, real-time polymerase chain reaction (PCR) and western blot analysis were used to analyze the expression of miR-34a and Tgif2 in gastric cancer tissues and the adjacent normal tissues. Next, gastric cancer cells were transfected with miR-34a mimic and Tgif2 siRNA, respectively. After transfection, real-time PCR and western blot analysis were used to detect the relative Tgif2 expression level. Cell proliferation was monitored by the colorimetric water-soluble tetrazolium salt and apoptosis analysis was performed with Annexin-V-FITC Apoptosis Detection Kit I. The expression of miR-34a in the adjacent non-tumor tissues was higher than that in gastric cancer tissues, but Tgif2 was opposite. In gastric cancer cells transfected with miR-34a mimic/Tgif siRNA, Tgif2 expression was remarkably down-regulated. Cells transfected with miR-34a mimic/Tgif2 siRNA grew more slowly than the control groups. The percentage of apoptotic cells in gastric cancer cells transfected with miR-34a mimic/Tgif siRNA was much higher compared to the controls. Therefore, we concluded that miR-34a could inhibit tumor invasion and metastasis in gastric cancer by targeting Tgif2 and may be a novel therapeutic candidate for gastric cancer.