Figure 6.

The molecular roles of circRNAs in the p53/Bcl-2 signaling pathway. p53 is a common tumor suppressor gene that regulates the cell cycle and apoptosis through various pathways. A direct interaction between p53 and circRNAs preserves p53 by preventing its ubiquitination by E3 ubiquitin ligases (such as MDM2). circRNAs also affect the downstream targets of p53, such as Bcl-2 or Bcl-2/caspase, which mediates apoptosis and is involved in tumor development. Nine upregulated and 5 downregulated circRNAs are indicated; 7 circRNAs regulate the p53/Bcl-2 signaling pathway through ceRNA effects. Red: upregulated circRNAs; blue: downregulated circRNAs.