ABSTRACT
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.
Subject(s)
MicroRNAs , RNA, Circular , Stomach Neoplasms , Cell Movement/genetics , Cell Proliferation/genetics , Humans , MicroRNAs/genetics , RNA, Circular/genetics , Receptor Tyrosine Kinase-like Orphan Receptors , Stomach Neoplasms/genetics , Tumor Cells, CulturedABSTRACT
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.
