circRNA_0006470 promotes the proliferation and migration of gastric cancer cells by functioning as a sponge of miR-27b-3p.

Cancer pathogenesis is influenced by epigenetic alterations mediated by circular RNAs (circRNAs). In this study, we aimed to investigate the regulatory mechanisms and cytological function of hsa_circ_0006470/miR-27b-3p in gastric cancer (GC). circRNA and microRNA expressions in cancer cells were measured by the qRT-PCR method. A dual-luciferase reporter assay was performed to validate the binding of hsa_circ_0006470 with miR-27b-3p. hsa_circ_0006470 was silenced in AGS cells, and proliferation, migration, and invasion were tested via the CCK-8 assay and Transwell system, respectively. The autophagy in GC cells was assessed by marker protein detection and transmission electron microscope. The results showed that hsa_circ_0006470 expression was significantly elevated in GC cells, which was mainly distributed in cytoplasmic components and could directly bind with miR-27b-3p in GC cells. Silencing of hsa_circ_0006470 repressed cell proliferation, migration, and invasion, which may be through regulating miR-27b-3p/Receptor tyrosine kinase-like orphan receptor 1 (ROR1). Silencing of hsa_circ_0006470 also elevated LC3II and Beclin-1 and suppressed p62 protein abundances, which subsequently induced autophagy in AGS cells. Furthermore, we found that hsa_circ_0006470 promotes phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PI3KCA) expressing by sponging miR-27b-3p. In conclusion, hsa_circ_0006470 promoted GC cell proliferation and migration through targeting miR-27b-3p and suppressing autophagy machinery.

Combined targeting of vascular endothelial growth factor C (VEGFC) and P65 using miR-27b-3p agomir and lipoteichoic acid in the treatment of gastric cancer.

BACKGROUND: Gastric cancer is the second leading cancer-related mortality worldwide and more effective treatment strategies are urgently needed to combat the disease. Using lipoteichoic acid (LTA) and miR-27b-3p agomir, we aimed to assess the efficacy of this combination of therapies in treating gastric cancer. METHODS: The RNA levels of miR-27b-3p, FOXO3, MET, KRAS, vascular endothelial growth factor C (VEGFC), TSC1, and P65 were analyzed by quantified-PCR (Q-PCR) and the cell viability of AGS cells was analyzed by MTT. Confirm Luciferase reporter assays were used to explore the putative miR-27b-3p binding sites and Western blot analyzed the protein level of GAPDH, VEGFC, P65, AKT, and phosphorylated-AKT (p-AKT). The level of P65 in both the cytoplasm and nucleus of AGS cells was visualized by immunofluorescence assay. Subcutaneous xenograft models of gastric cancer were established, and mice were treated with miR-27b-3p agomir, LTA, or both. Hematoxylin-eosin staining and Ki-67 immunohistochemistry analysis of tumor tissues were then performed. RESULTS: The results showed that the decreased expression of miR-27b-3p in gastric cancer cell lines inhibited the viability of AGS cells, and VEGFC was confirmed as the target of miR-27b-3p. In addition, ectopic expression of miR-27b-3p significantly inhibited the AKT pathway in AGS and N87 cells, and LTA suppressed the proliferation of gastric cancer cells by inhibiting the NF-κB pathway. In an established xenograft model, both miR-27b-3p agomir alone and LTA treatment alone inhibited tumor growth and treatment which combined the two showed an even stronger inhibitory effect. CONCLUSIONS: Taken together, the combined use of LTA and miR-27b-3p agomir exhibited a synergistic effect in the treatment of gastric cancer.

LncRNA FAM230B Promotes Gastric Cancer Growth and Metastasis by Regulating the miR-27a-5p/TOP2A Axis.

AIM: Long non-coding RNAs serve as key components of competing endogenous RNA (ceRNA) networks that underlie tumorigenesis. We investigated the pathogenic roles of lncRNA FAM230B and its molecular mechanism in gastric cancer (GC). METHOD: The levels of FAM230B expression in five gastric cancer cell lines and in human gastric mucosal cells were compared by quantitative RT-PCR. To analyze the function of FAM230B in GC, we overexpressed FAM230B in AGS cells, silenced FAM230B in MGC-803 cells, and tested the effect of FAM230B on tumor growth in nude mice. The interaction between miR-27a-5p and FAM230B was predicted by a bioinformatics analysis and then verified with a dual-luciferase reporter assay. We also further investigated the role and mechanism of FAM230B by forcing overexpression of miR-27a-5p in MGC-803 gastric cancer cells. RESULTS: We found that FAM230B was highly expressed in gastric cancer cell lines and mainly located in the cytoplasm. FAM230B overexpression promoted the proliferation, migration, and invasion of AGS cells and repressed their apoptosis; it also facilitated tumor growth in vivo. In contrast, FAM230B knockdown suppressed the proliferation, migration, and invasion of MGC0803 cells, but enhanced their apoptosis and inhibited tumor growth in vivo. MiR-27a-5p expression was suppressed by FAM230B overexpression in AGS cells. MiR-27a-5p inhibited the proliferation, migration, and invasion of gastric cancer cells, and promoted the apoptosis of gastric cancer cells by reducing TOP2A (topoisomerase 2 alpha) expression. CONCLUSION: Our study showed that lncRNA FAM230B might function to promote GC. FAM230B functioned as a ceRNA by sponging miR-27a-5p and enhancing TOP2A expression.