Targeting GPR133 <i>via</i> miR-106a-5p inhibits the proliferation, invasion, migration and epithelial-mesenchymal transition (EMT) of glioma cells

<b>Background:</b> Glioma is the most common malignant brain tumor. GPR133 is a key factor in the progression of glioma. However, the role of GPR133 in glioma invasion and EMT and the microRNAs (miRNAs) associated with this pathway are still poorly understood.<b>Objective:</b> This study aims to elucidate the biological function of miR-106a-5p and GPR133 in glioma as well as the molecular mechanism of their interaction.<b>Methods:</b> The mRNA expression of miR-106a-5p and GPR133 in glioma specimens and cells was analyzed by quantitative real-time polymerase chain reaction (qRT–PCR). The protein level of GPR133 and the levels of invasion- and EMT-related proteins were measured by western blotting. miR-106a-5p and GPR133 function in glioma cells was determined through cell counting kit-8 (CCK-8), transwell, wound healing, colony formation assays <i>in vitro</i> and xenograft assays <i>in vivo</i>. To determine the targeting relationship between miR-106a-5p and GPR133, a dual-luciferase reporter assay was conducted.<b>Results:</b> A marked reduction in miR-106a-5p expression was observed in glioma cells and specimens. Patients with high expression of miR-106a-5p had a good prognosis, while patients with high expression of GPR133 had a shorter OS. Additionally, overexpression of miR-106a-5p or downregulation of GPR133 inhibited the progression of glioma cells. Furthermore, miR-106a-5p negatively regulated GPR133 expression by binding to its 3′-UTR, and restrained the invasion, migration, proliferation and EMT of glioma cells by targeting GPR133.<b>Conclusions:</b> miR-106a-5p is a tumor suppressor that negatively regulates GPR133. The miR-106a-5p/GPR133 axis could potentially serve as a therapeutic target for glioma.