CircFAT1 Sponges MiR-375 To Promote The Expression Of Yes-Association Protein 1 In Osteosarcoma Cells

ObjectivesThere is an urgent need to identify new molecular targets for the treatment of osteosarcoma.Circular RNA is a class of endogenous RNA that is widely present in mammalian cells and plays a key role in regulating gene expression.However,in osteosarcoma,the underlying molecular mechanism of circular RNA is still poorly understood.Here,we evaluated the function and characteristics of circular RNA circFAT1 in osteosarcoma in the development of osteosarcoma.MethodsFirst,in vitro experiments were performed to determine the characteristics of circular RNA of circFAT1 in osteosarcoma,and to evaluate the effects of circFAT1 / miR-375 / YAP1 on human osteosarcoma cell growth,apoptosis,migration,invasion and tumorigenesis.Through Western blot,fluorescent quantitative chain amplification reaction,fluorescence in situ hybridization,chromogenic in situ hybridization,RNA-binding protein immunoprecipitation and immunofluorescence analysis related signal pathways,and the binding mode,function and specific binding site of circFAT1 and miR-375.The function and role of circFAT1 and miR-375 in the development of osteosarcoma and the specific binding mode between them were evaluated in tumor-grown mice bearing 143 B osteosarcoma cell xenografts.ResultIn this study,we observed that circFAT1 produced by exon 2 of the FAT1 gene in human osteosarcoma tissues and cell lines was significantly up-regulated.Reducing circFAT1 in osteosarcoma cells effectively prevents osteosarcoma cell migration,invasion and tumorigenesis,and inhibits osteosarcoma growth in vivo.We observed that human osteosarcoma tissue and cell line miR-375 were significantly down-regulated.Increasing miR-375 in osteosarcoma cells can effectively prevent osteosarcoma cell migration,invasion and tumorigenesis,and inhibit the growth of osteosarcoma in vivo.Mechanistic studies have shown that circFAT1 contains a site that binds to micro RNA-375(miR-375)and can absorb miR-375 in large quantities to up-regulate the expression of Yes-related protein 1.In addition,inhibition of miR-375 reversed the weakened cell proliferation,and circFAT1 knockdown induced cell migration and invasion,thereby promoting tumorigenesis.ConclusionThis study found that circFAT1 was able to specifically adsorb miR-375 and prevent miR-375 from binding to YAP m RNA.It proved the new functions of circFAT1 and miR-375 in the occurrence and development of osteosarcoma,and revealed and proposed a new treatment target for osteosarcoma.