Tumor Cell-Derived Exosomal hsa_circ_0017252 Suppresses the Tumorigenesis of Gastric Cancer Through Suppressing M2 Polarization of Macrophage

Abstract Background: Gastric cancer (GC) is a source of global cancer death. MiR-17-5p is reported to regulate the tumorigenesis of GC. Meanwhile, hsa_circ_0017252 is known to be upregulated in GC. However, the relation between hsa_circ_0017252 and miR-17-5p in GC remains unclear. Methods: Cell viability, migration and invasion were tested by CCK-8 and transwell assay, respectively. Gene expressions were detected by RT-qPCR, and the protein levels in cells or exosomes were tested by western blot. The efficiency of exosomes isolation was investigated by transmission electron microscope (TEM) and nanoparticle tracking analysis (NTA). Meanwhile, cell apoptosis was tested by flow cytometry. In vivo model was constructed to assess the function of MKN45 cells-derived exosomal hsa_circ_0017252 in GC. Results: Hsa_circ_0017252 was verified to be significantly downregulated in GC tissues. Hsa_circ_0017252 upregulation significantly decreased the viability and migration of GC cells, and hsa_circ_0017252 could bind with miR-17-5p. Additionally, exosomal hsa_circ_0017252 reversed the polarization of M2 macrophages, and the polarized macrophages decreased the GC cell invasion. Furthermore, exosomes with upregulated hsa_circ_0017252 suppressed the tumor growth of GC. Conclusion: Delivery of hsa_circ_0017252 by GC cells-derived exosomes inhibits the tumorigenesis of GC through reversing M2 polarization of macrophages. Thus, our finding might provide a new method for GC treatment.