Circular RNA circ-FAM158A promotes retinoblastoma progression by regulating miR-138–5p/SLC7A5 axis

Abstract

BackgroundMounting evidence has shown that circular RNAs (circRNAs) have vital roles in human cancers, including retinoblastoma (RB). The purpose of this study was to investigate the exact roles and underlying mechanism of circRNA ER membrane protein complex subunit 9 (circ-FAM158A) in RB. MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) was carried out to determine the expression levels of circ-FAM158A, miR-138–5p and solute carrier family 7 member 5 (SLC7A5). Cell proliferation was evaluated by Cell counting Kit-8 (CCK-8) assay and colony formation assay. Flow cytometry analysis was applied to determine cell cycle distribution and apoptosis rate. Transwell assay was conducted to assess cell migration and invasion. The interaction between miR-138–5p and circ-FAM158A or SLC7A5 was predicted by starBase v2.0 and confirmed by dual-luciferase reporter assay. Western blot assay was performed to examine the protein expression of SLC7A5. The mice xenograft model was established, immunohistochemistry (IHC) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) assays were conducted to confirm the role of circ-FAM158A in vivo. ResultsCirc-FAM158A and SLC7A5 were overexpressed and miR-138–5p was downregulated in RB tissues and cells. Circ-FAM158A knockdown inhibited RB cell proliferation, metastasis, and promoted apoptosis in vitro and in vivo. MiR-138–5p was a direct target of circ-FAM158A, and miR-138–5p inhibition reversed the inhibitory effect of circ-FAM158A silence on the progression of RB cells. Additionally, SLC7A5 was identified as a target of miR-138–5p, and SLC7A5 overexpression abated the anti-tumor roles of miR-138–5p in RB cells. Besides, circ-FAM158A positively regulated SLC7A5 expression by sponging miR-138–5p. ConclusionCirc-FAM158A knockdown inhibited the progression of RB by regulating miR-138–5p/SLC7A5 axis, which provided new insights into the pathogenesis of RB.