Objective To explore the influence of circular RNA_0005273 (circ_0005273) on biological behavior of esophageal cancer cells and its possible mechanism.
Methods The genetic expression levels of circ_0005273, microRNA-1200 (miR-1200) and protein expression level of signal transducer and activator of transcription 3 (STAT3) in esophageal cancer tissues, paracancerous tissues and human esophageal cancer cells EC109 were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot respectively. EC109 cells were normally cultured and named as control group, and the si-NC, si-circ_0005273, miR-NC, miR-1200 and si-circ_0005273+anti-miR-1200 were respectively transfected into EC109 cells and named as si-reference group, si-circ group, miR-reference group, miR-1200 group and si-circ+anti group. Methyl Thiazolyl Tetrazolium (MTT) assay, colony formation assay, flow cytometry and Transwell assay were used to detect inhibition rate of cell proliferation, the number of colony formation, cell apoptosis rate and the number of cell migration; the targeted regulatory relationships of miR-1200 with circ_0005273 and STAT3 were analyzed by dual-luciferase reporter assay.
Results The protein expression levels of circ_0005273 and STAT3 in the esophageal cancer tissues were significantly higher than those in the paracancerous tissues, while the expression level of miR-1200 was significantly lower than that in the paracancerous tissues (P < 0.05); the expression level of miR-1200, inhibition rate of cell proliferation and cell apoptosis rate in the si-circ group were significantly higher than those in the control group and si-reference group, while the expression level of circ_0005273, protein expression level of STAT3, the number of colony formation and the number of migrating cells were significantly lower than those in the control group and si-reference group (P < 0.05); the protein expression level of STAT3, the number of colony formation and the number of migrating cells in the miR-1200 group were significantly lower than those in the control group and miR-reference group, while the expression level of miR-1200, inhibition rate of cell proliferation and apoptosis rate were significantly higher than those in the control group and miR-reference group (P < 0.05). The circ_0005273 was able to regulate miR-1200 and miR-1200 was able to regulate STAT3 by targeted therapy. Protein expression level of STAT3, the number of colony formation and the number of migrating cells in the si-circ+anti group were significantly higher than those in the si-circ group, while inhibition rate of cell proliferation and apoptosis rate were significantly lower than those in the si-circ group (P < 0.05).
Conclusion The circ_0005273 is highly expressed in esophageal cancer tissues, and interference of circ_0005273 can inhibit the proliferation and migration of esophageal cancer cells as well as induce cell apoptosis by up-regulating expression of miR-1200 and down-regulating expression of STAT3.
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