TABLE 1.
Source, localization, mechanism, and biological function of circRNAs
| CircRNAs | Location | Mechanisms of action | Molecule/axe/signaling pathway | Biological function | Reference |
|---|---|---|---|---|---|
| Hsa‐circ‐0001492(circ‐ERBIN) | Cytoplasm | HIF‐1α was upregulated by targeting miR‐125a‐5p and miR‐138‐5p sponging | miR‐125a‐5p/miR‐138‐5p/4EBP‐1 | Carcinogenic function, promote tumor angiogenesis, and increase the level of HIF‐1α protein | [56] |
| Hsa‐circ‐0069313(circ‐PACRGL) | Cytoplasm | As the sponges of miR‐142‐3p and miR‐506‐3p | miR‐142‐3p/miR‐506‐3p/TGF‐β1 | Carcinogenic function, promote the expression of TGF‐β1, participate in tumor immune response, and promote the differentiation of N1–N2 neutrophils | [53] |
| Circ‐CDR1as | Cytoplasm | The stability of target gene miR‐7 was regulated through the sponging effect of miRNAs | miR‐7/HOXB13 | Carcinogenic function, regulate insulin secretion, promote CRC cell proliferation, and differentiation and tumor metastasis | [55] |
| Hsa‐circ‐0008558(circ‐LONP2) | Nucleus | Under FUS regulation, pre‐mLONP2 can be transformed into circLONP2, which recruits DGCR8 in a DDX1‐dependent manner and promotes the maturation of miR‐17‐5p | Not applicable | Carcinogenic function, driving mature miR‐17‐5p to bind to exosomes has high metastasis potential, and promoting the proliferation and metastasis of CRC | [7] |
| Hsa‐circ‐0003315(circ‐GLG1) | Cytoplasm | As a sponge of miR‐622, the length is about 477 nucleotides | miR‐622/KRAS | Carcinogenic function, promote the proliferation and metastasis of CRC, which can be used as biomarkers for clinical diagnosis of CRC | [119] |
| Hsa‐circ‐0000384(circMRPS35) | Nucleus | Recruit KAT7 to attach to the promoters of FOXO1 and FOXO3a to increase the level of H4K5 acetylation | KAT7/H4K5/FOXO1/3a | Antitumor effect, negatively related to tumor lymph node metastasis, TNM staging, and tumor size | [23] |
| Circ‐NSD2 | Cytoplasm (main), nucleus | As a sponge of miR‐199b‐5p, activated DDR1 and JAG1 genes are involved in histone modification | miR‐199b‐5p/DDR1/JAG1 | Oncogenic function, as a histone methyltransferase coordinator, helps CRC cell matrix interaction, migration, and metastasis, providing a diagnostic target for the treatment of CRC liver metastasis | [18] |
| Hsa‐circ‐002144 | Cytoplasm | As a sponge for miR‐615‐5p | miR‐615‐5p/LARP1 | Carcinogenic function, regulate LARP1 to promote the progression of colorectal cancer, and provide a therapeutic target for tumor intervention | [25] |
| Hsa‐circ‐0000677 (circABCB10) | Cytoplasm | CircABCB10 targets sponge miR‐326 and interacts with CCL5 | miR‐326/CCL5 | Knockdown of cirABCB10 can promote iron death and apoptosis of CRC cells and inhibit the proliferation and metastasis of CRC | [93] |
| Hsa‐circ‐0008367(circ‐IARS) | Cytoplasm | The interaction of circ‐IARS with RBP (ALKBH5) inhibited the autophagy and ferritin phagocytosis of ALKBH5 | circ‐IARS/ALKBH5 | Carcinogenic function, induces iron death to participate in tumor proliferation and metastasis | [27] |
| Hsa‐circ‐0005963(ciRS‐122) | Nucleus | Sponge action targeting miR‐122 via PKM2 | miR‐122 /PKM2 | It promotes the aerobic oxidation of the glycolysis of CRC and produces a large amount of ATP, which in turn promotes the growth of CRC and the resistance to chemotherapy | [97] |
| Circ‐FBXW7 | Cytoplasm | Circ‐FBXW7 is a sponge for miR‐18b‐5p in CRC cells and is negatively correlated with miR‐18b‐5p | circ‐FBXW7/miR‐18b‐5p | Antitumor effect, increase the chemotherapy resistance of oxaliplatin in CRC cells | [98] |
| Hsa‐circ‐000984 | Cytoplasm | Competitive binding of miR‐106b exerts the role of ceRNA and upregulates the expression of CDK6 | miR‐106b/CDK6 | The carcinogenic effect was significantly correlated with advanced T`NM (stage 3 + stage 4) | [38] |
| Hsa‐circ‐0000284(circHIPK3) | Cytoplasm | CircHIPK3 regulates FMNL2 through the sponge action of miR‐1207‐5p | miR‐1207‐5p/FMNL2 | Carcinogenic effect, promote the proliferation, and invasion and metastasis of CRC | [87] |
| Hsa‐circ‐0066631, hsa‐circ‐0082096 | Nucleus | Sponge targeting of miRNAs, such as miR‐140‐3p, miR‐224, miR‐382, miR‐548c‐3p, and miR‐579 | ACVR1C/ALK7, FZD3, IL6ST/GP130, SKIL/SNON, SMAD2, WNT5; TGF‐β/SMAD, Wnt/β‐catenin | Rich in cancer stem cells, involved in the recurrence and metastasis of CRC | [100] |
| CircRNA‐0000392 | Cytoplasm | The expression of PIK3R3 was regulated by the sponges of miR‐193a‐5p | miR‐193a‐5p/PIK3R3/AKT | The carcinogenic effect promotes the proliferation and invasion of CRC, which can be used as therapeutic targets and biomarkers for colorectal cancer | [13] |
| CircRUNX1 | Cytoplasm | CircRUNX1 acts as a sponge of miR‐145‐5p to upregulate IGF1 | miR‐145‐5p/IGF1 | As a tumor promoter, it is involved in the proliferation, invasion, cell cycle progression, and apoptosis of CRC cells | [105] |
| Hsa‐circ‐0006990(circVAPA) | Cytoplasm | CircVAPA targeting sponge miR‐101‐3p | Not applicable | Significantly promote the proliferation, migration, and metastasis of CRC, and participate in the cell cycle process; Inhibit cell apoptosis, which is expected to become a potential therapeutic target for CRC | [14] |
| Hsa‐circ‐0136666(circ‐PRKDC) | Cytoplasm | Circ‐PRKDC promotes DDR1 mRNA and protein expression in CRC tissues by targeting miR‐198 through the sponging effect of miR‐198 | miR‐198 /DDR1 | Carcinogenic function, promote the proliferation, and invasion and metastasis of CRC | [89] |
| Hsa‐circ‐0000598(circ‐001680) | Cytoplasm | Circ‐001680 enhanced BMI1 expression by spongy inhibition of miR‐340. At the same time, BMI1 also regulates the stem cell‐like properties of cancer | miR‐340/BMI1 | Carcinogenesis, which is related to clinical T staging of CRC patients, induces resistance of CRC to irinotecan, reduces apoptosis of colorectal cancer cells, and participates in recurrence and metastasis of CRC | [101] |
| Has‐circ‐02276(circLgr4) | Nucleus | Peptide coding ability, involved in protein coding and regulation in a peptide‐dependent manner | Peptide/Lgr4 | Carcinogenesis, encoding proteins, and participating in CSC self‐renewal, tumor recurrence, and metastasis in colorectal cancer | [57] |
Abbreviations: 4EBP‐1, 4E binding protein 1; CCL5, C‐C motif chemokine ligand 5; CDK6, cyclin‐dependent kinase 6; CRC, colorectal cancer; HIF‐1α, Hypoxia‐inducible factor‐1α; IGF1, insulin‐like growth factor 1; PKM2, the M2 subtype of pyruvate kinase; TGF‐β1, transforming growth factor‐β1.