Circ_0000069 contributes to the growth, metastasis and glutamine metabolism in renal cell carcinoma (RCC) via regulating miR-125a-5p-dependent SLC1A5 expression

Background: Circular RNAs (circRNAs) have emerged as critical mediators in various cancers, including renal cell carcinoma (RCC). In the present research, the functions of circ_0000069 in RCC were explored.Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) assay, western blot assay and immuno-histochemistry (IHC) assay were performed for the expression of circ_0000069, microRNA-125a-5p (miR-125a-5p) and solute carrier family 1 member 5 (SLC1A5). Cell Counting Kit-8 (CCK-8) assay and 5 '-ethynyl-2 '-deox-yuridine (EdU) assay were performed for cell proliferation. Flow cytometry assay was manipulated for cell apoptosis. Transwell assay and wound-healing assay were utilized for cell invasion and migration. Glutamine metabolism level was evaluated by examining glutamine consumption, alpha-ketoglutarate production and gluta-mate production. Dual-luciferase reporter assay was used to analyze the relationships of circ_0000069, miR-125a-5p and SLC1A5. Murine xenograft model assay was conducted to analyze the function of circ_0000069 in vivo.Results: Circ_0000069 level was abnormally upregulated in RCC tissues and cells. Knockdown of circ_0000069 inhibited the proliferation, invasion, migration and glutamine metabolism and promoted the apoptosis in RCC cells in vitro and restrained tumor growth in vivo. Circ_0000069 served as the sponge for miR-125a-5p. MiR-125a-5p inhibition ameliorated the effects of circ_0000069 knockdown on RCC cell malignant behaviors. SLC1A5 was identified as the target gene of miR-125a-5p. Moreover, miR-125a-5p overexpression repressed the pro-gression of RCC cells, while SLC1A5 elevation abrogated the effect.Conclusion: Circ_0000069 knockdown inhibited the carcinogenesis of RCC by regulating miR-125a-5p/SLC1A5 axis.