miR-21 Inhibitors Modulate Biological Functions of Gastric Cancer Cells via PTEN/PI3K/mTOR Pathway.

Gastric cancer is one of the most common malignancy in the world. microRNAs (miRNAs) are naturally occurring noncoding RNA that control gene expression by targeting messenger RNA (mRNA) for post-transcriptional repression or cleavage. This study focused on a specific miRNA, miR-21, which was overexpressed in gastric cancer and examined the effects of miR-21 inhibitor on biological functions of gastric cancer cells and its possible mechanism. Gastric cancer cells MKN74 were treated with miR-21 inhibitor, negative control, and blank control. Cell proliferation, colony formation, migration, and invasion were assessed. Real-time PCR and western blot were applied to examine the expression of phosphatase and tens in homolog deleted on chromosome ten (PTEN)/PI3K/mTOR pathway molecules. miR-21 inhibitor markedly suppressed proliferation, migration, invasion, and colony formation of gastric cancer cells. Anti-miR-21 treatment also reduced the expression ratio of B cell lymphoma 2 (Bcl-2)/Bax. Furthermore, miR-21 inhibition was associated with increased expression of PTEN, which in turn decreased the ratios of S235/236, S240/244, and p-AK/AKT in gastric cancer cells. Inhibiting miR-21 modulates biological functions of gastric cancer cells via PTEN/PI3K/mTOR pathway and miR-21 inhibitor may provide a novel therapeutic strategy for gastric cancer.