Role of circular RNAs in gastrointestinal tumors and drug resistance

Table 1 circRNAs involved in gastric cancer gene transcription regulation and drug resistance

Cancer species	circRNA	Gene expression		Mechanism	Drug	Ref.
		Up	Down
Gastric cancer	circRNA100876	↑		Via miR-665/YAP1 signaling pathway	NR	[66]
Gastric cancer	circCUL3	↑		Acts as a sponge for miR-515-5p	NR	[67]
Gastric cancer	circTMEM87A	↑		Acts as a sponge for miR-142-5p	NR	[68]
Gastric cancer	circRNA0044516	↑		Acts as a sponge for miR-149	NR	[69]
Gastric cancer	circ0000039	↑		Acts as a sponge for miR-1292-5p	NR	[70]
Gastric cancer	has-circ-0004872		↓	Acts as a sponge for miR-224	NR	[71]
Gastric cancer	circ-ITCH		↓	Negative regulation of Wnt/β-catenin signaling pathway	NR	[72]
Gastric cancer	circPDZD8	↑		Acts as a sponge for miR-197-5p	NR	[73]
Gastric cancer	circMTHFD2	↑		Combined with miR-124 to exert sponge effect and induce MDR-1 protein	Pemetrexed	[74]
Gastric cancer	circ-PVT1	↑		By negatively regulating miR-124-3p	Paclitaxel	[75]
Gastric cancer	circAKT3	↑		Promote PIK3R1 expression through miR-198	Cisplatin	[76]
Gastric cancer	circFhashsa-circ-0058147	↑		Regulation of cisplatin activity via miR-182-5p	Cisplatin	[77]

NR: Not reported; circRNA: Circular RNA.

Table 2 circRNAs involved in liver cancer gene transcription regulation and drug resistance

Cancer type	circRNA	Gene expression		Mechanism	Drug	Ref.
		Up	Down
Liver cancer	circ100084	↑		Promotes IGF2 expression by acting as a sponge for HSA-MIR-23A-5P	NR	[81]
Liver cancer	circABCB10	↑		Upregulates HMG20A expression by acting as a miR-670-3p sponge	NR	[83]
Liver cancer	circRNA-101237	↑		Increased levels in serum and Huh7 cells of cisplatin-resistant HCC patients	Cisplatin	[84]
Liver cancer	Hsa-circ-u0006294, hsa-circ-u0035944, hsa-circ-u0084663		↓	Plays a role by activating the Wnt/β-catenin pathway	Sorafenib	[85]
Liver cancer	circ-0003418		↓	Inhibits Wnt/β-catenin pathway	Cisplatin	[86]
Liver cancer	circFBXO11	↑		Uses miR-605 /FOXO3/ABCB1 axis adjustment	Oxaliplatin	[87]

NR: Not reported; circRNA: Circular RNA.

Table 3 circRNAs involved in colon cancer gene transcription regulation and drug resistance

Cancer type	circRNA	Gene expression		Mechanism	Drug	Ref.
		Up	Down
Colon cancer	circNSUN2	↑		Interact with YTHDC1, SRSF3 and NXF1	NR	[91]
Colon cancer	hsa-circ-101555	↑		Acts as miR-597-5p sponge	NR	[92]
Colon cancer	circHIPK3	↑		Acts as miR-7 sponge	NR	[93]
Colon cancer	circCCDC66	↑		DHX9 phosphorylation	Oxaliplatin	[94,95]
Colon cancer	circ-001680	↑		Adjust BMI1 via miR-340	Irinotecan	[98]
Colon cancer	hsa-circ-0005963	↑		Acts as miR-122 sponge	Oxaliplatin	[99]
Colon cancer	circ-0000338	↑ or ↓		Knock out circ-0000338 improves drug resistance	5-FU	[100]
Colon cancer	hsa-circ-32883	↑		uncertain	5-FU, oxaliplatin	[101]
Colon cancer	circ0007031, circ0000504, circ0007006	↑		Use hsa-miR485-5p pathway	5-FU	[102]
Colon cancer	hsa-circ-0079662	↑		Using the TNF-α pathway	oxaliplatin	[103]
Colon cancer	circDDX17	↑		Adjustable via miR-31-5p/KANK1 axis	5-FU	[104]

NR: Not reported; circRNA: Circular RNA.

Table 4 circRNAs involved in esophageal cancer gene transcription regulation and drug resistance

Cancer type	circRNA	Gene expression		Mechanism	Drug	Ref.
		Up	Down
Esophageal cancer	circUBAP2	↑		Acts as miR-422a sponge	NR	[108]
Esophageal cancer	hsa-circ-0006948	↑		miR-490-3p to enhance HMGA2-induced EMT	NR	[109]
Esophageal cancer	circ-0000654	↑		miR-149-5p/IL-6/STAT3 pathway	NR	[110]
Esophageal cancer	circGSK3	↑		β-catenin signal passing	NR	[111]
Esophageal cancer	circ-Foxo3		↓	miR-23a/PTEN pathway	NR	[112]
Esophageal cancer	circPVT1	↑		Acts as miR-4663 sponge	NR	[113]
Esophageal cancer	ciRS-7	↑		Acts as a miR-876-5p sponge	Rapamycin	[114,115]
Esophageal cancer	circRNA-001275	↑		Acts as a miR-370-3p sponge	Cisplatin	[117]

NR: Not reported; circRNA: Circular RNA.

Table 5 circRNAs involved in pancreatic cancer gene transcription regulation and drug resistance

Cancer type	circRNA	Gene expression		Mechanism	Drug	Ref.
		Up	Down
Pancreatic cancer	circBFAR	↑		Acts as a miR-34b-5p sponge	NR	[119]
Pancreatic cancer	circFOXK2	↑		Acts as miR-942 sponge	NR	[120]
Pancreatic cancer	circ-ADAM9	↑		Activate ERK/VEGF signaling pathway through miR-217	NR	[121]
Pancreatic cancer	circ-ASH2L	↑		Acts as a sponge for miR-34a	NR	[122]
Pancreatic cancer	circ-LDLRAD3	↑		Adjustable via miR-137-3p/PTN axis	NR	[123]
Pancreatic cancer	circ-0000977	↑		Acts as a sponge for miR-153	NR	[124]
Pancreatic cancer	hsa-circRNA-0007334	↑		Competitive binding through hsa-miR-144-3p	NR	[125]
pancreatic cancer	ciRS-7	↑		Acts as miR-7 sponge	NR	[126]
Pancreatic cancer	circ-0030235	↑		Acts as miR-1253 and miR-1294 sponge	NR	[127]
Pancreatic cancer	circZMYM2	↑		Acts as a miR-335-5p sponge	NR	[128]
Pancreatic cancer	circ-0007534	↑		Acts as miR-625, miR-892b sponge	NR	[129]
Pancreatic cancer	circ-IARS	↑		Acts as miR-122 sponge	NR	[130]
Pancreatic cancer	circ-PDE8A	↑		As a sponge of miR-338 to regulate MACC1	NR	[131]
Pancreatic cancer	circHIPK3	↑		Acts as a miR-330-5p sponge	Gemcitabine	[133]

NR: Not reported; circRNA: Circular RNA.