Exosomal circKIAA1797 Regulates Cell Progression and Glycolysis by Targeting miR-4429/PBX3 Pathway in Gastric Cancer.

In recent years, circular RNAs (circRNAs) are extensively studied in the progression of various types of cancer, while the mechanism of circKIAA1797 is rarely studied in gastric cancer (GC). Hence, this research aimed to investigate the expression of exosomal circKIAA1797 and its biological function in GC cells. Exosomes were extracted from the serum of GC patients and identified by transmission electron microscopy (TEM) and nanoparticle tracking analyzer (NTA). CD81, CD63, Bcl-2, Bax, and pre-leukemia transcription factor 3 (PBX3) protein levels were detected using western blot assay. circKIAA1797, microRNA-4429 (miR-4429), and PBX3 mRNA were determined by quantitative real-time PCR (RT-qPCR). Cell proliferation, migration, invasion, and apoptosis were assessed using colony formation assay, 5-Ethynyl-2'-deoxyuridine (EdU) assay, transwell assay, and flow cytometry assay. Glucose consumption and lactate production levels were examined using glycolysis detection kits. The interaction between miR-4429 and circKIAA1797 or PBX3 was identified using dual-luciferase reporter assay, RNA pull-down assay, and RNA immunoprecipitation (RIP) assay. Xenograft mouse model assay was used to investigate the effect of exosomal circKIAA1797 in vivo. It was found that circKIAA1797 was up-regulated in GC tissues and cells, as well as in the exosomes derived from the serum of GC patients. Silencing of exosomal circKIAA1797 could hamper cell progression and glycolytic metabolism of GC. Mechanically, circKIAA1797 acted as a sponge of miR-4429 to regulate PBX3 expression. Moreover, the knockdown of exosomal circKIAA1797 repressed tumor growth in vivo. Our data demonstrated that knockdown of exosomal circKIAA1797 suppressed GC malignant phenotypes by regulating miR-4429/PBX3 axis, which might offer a promising therapeutic strategy for GC treatment.