Fig. 1
From: Circular RNAs function as ceRNAs to regulate and control human cancer progression
circRNAs serve as endogenous RNA competitors. A linear RNA precursor can be cis-spliced into linear RNA, and special sequences in the RNA precursor can combine to form a cycle to produce circRNAs. circRNAs act as endogenous RNA competitors to absorb microRNA (miRNA); as a result, the activity of the corresponding miRNA is reduced. miRNAs mainly act on mRNAs, and circRNA competition process blocks miRNAs from regulating the expression of target genes. This interaction between circRNAs and miRNAs has been shown to also occur in exosomes