miR-7160 inhibits gastric cancer cell proliferation and metastasis by silencing SIX1.

Upregulation of homeoprotein SIX1 in gastric cancer (GC) is related to tumour proliferation and invasion. MicroRNA-7160 (miR-7160) is a homeoprotein SIX1-targeting miRNA that downregulates miR-7160, leading to cancer development. Total gastric cancer samples were collected from six patients, and relative expression levels of SIX1 mRNA and miRNAs were analysed by qRT-PCR. To evaluate the regulation of SIX1 by miR-7160, pGL3-SIX1-mut, pGL3-SIX1, and miR-7160 mimics transfected into cells using lipofectamine 2000. After transfection, proliferation and apoptosis in cultured cells were assessed using the nuclear TUNEL staining and CCK8 reagent, respectively. We demonstrated that the downregulation of miR-7160 in human gastric cancer cells is related to the upregulation of SIX1 mRNA. In gastric cancer cell lines, miR-7160 overexpression could downregulate the expression and inhibit cancer cell proliferation and growth in vitro. However, overexpression of miR-7160 did not increase gastric cancer cell apoptosis. In vitro downregulation of SIX1 decreased vimentin, N-cadherin, and other EMT-related gene expression and increased E-cadherin expression. In brief, miR-7160, by targeting SIX1, inhibits gastric cancer proliferation and cell growth in vitro, which provides an idea for introducing a new treatment option for gastric cancer.