Upregulated circRNA_100269 suppresses the growth and metastasis of gastric cancer by inactivating PI3K/Akt signaling pathway

Abstract

Background: The expression of circRNA_100269 in gastric cancer (GC) tissues and cells, together with its regulatory roles on GC cells were investigated. Methods: The levels of circRNA_100269 in GC and matched para-carcinoma tissues, as well as in human GC cell lines and normal gastric epithelial cells were evaluated using RT-qPCR. The models with overexpression or knockdown of circRNA_100269 were generated using lentiviral vectors. Cell viability was examined using MTT assay; cell migration and invasive activity were determined by wound healing and Transwell assay. Cell cycle arrest and apoptosis were assessed; molecules involved in PI3K/Akt signaling, apoptosis and EMT were evaluated using RT-qPCR and immunoblotting. Tumour growth and expression of relevant proteins were examined in circRNA_100269 knockout mice. Results: The results indicated the expression of circRNA_100269 was dramatically decreased in GC samples compared with para-carcinoma tissues (p<0.05), while the levels of PI3K were notably increased (p<0.05). Moreover, the level of circRNA_100269 was relevant to histology grade and occurrence of metastasis in GC patients (p<0.05), where circRNA_100269 and PI3K was inversely correlated (p<0.05). Additionally, circRNA_100269 was downregulated in GC cells compared with normal gastric epithelial cells. Overexpressed circRNA_100269 remarkably suppressed the proliferation, migration, invasion and EMT of GC cells (p<0.05), induced cell cycle arrest at G0/G1 phase and promoted cell apoptosis (p<0.05). In addition, PI3K/Akt signaling was involved in circRNA_100269-mediated proliferation, migration, invasion, EMT and apoptosis in GC cells (p<0.05). Knockdown of circRNA_100269 also significantly promoted tumor growth in vivo (p<0.05). Conclusions: the data of the present study suggested that the expression level of circRNA_100269 was decreased in GC tissues and cells. In addition, circRNA_100269 inhibited the progression of GC by suppressing PI3K/Akt signaling. Therefore, circRNA_100269/PI3K/Akt axis may be a potential therapeutic target for GC treatment.