Circular RNA circ-ABCB10 Promotes Proliferation and Inhibits Apoptosis of Laryngeal Carcinoma by Inhibiting KLF6

OBJECTIVE: To explore the effect of circular RNA circ-ABCB10 on the proliferation and apoptosis of laryngeal carcinoma via inhibiting KLF6. METHODS: RT-qPCR assay was adopted to detect the expression of circ-ABCB10 and KFL6 in laryngeal carcinoma tissues and cell lines. Cell counting kit-8 (CCK-8) and clone formation assay were employed to detect laryngeal cancer cell viability and proliferation when circ-ABCB10 was silenced or upregulated. In this study, the apoptosis rate was detected by flow cytometry and the protein expression was detected by Western blotting. Wound healing and cross-hole invasion were used to study the migration and invasion of laryngeal cancer cells when circ-ABCB10 was silenced or upregulated. RESULTS: The results of RT-qPCR detection indicated that the expression of circ-ABCB10 in all three laryngeal carcinoma cells was downregulated by 3.2 times compared with that of HaCat cells. There is low expression of circ-ABCB10 in most laryngeal carcinoma tissues, the diagnostic cutoff value of circ-ABCB10 is 0.0008, the area under the curve is 0.718, the sensitivity is 0.981, and the specificity is 0.556. The expression level of KLF6 in laryngeal carcinoma is on the rise, which is significantly higher compared to healthy tissues (P < 0.05); 48 hours after transfection, RT-qPCR analysis confirmed the transfection efficiency, and upregulation of circ-ABCB10 could significantly promote cell proliferation. Compared with the control group, silencing circ-MTCL1 could inhibit cell proliferation, overexpression of circ-ABCB10 promoted cell migration, and downregulation of circ-ABCB10 significantly inhibited cell movement (P < 0.001). Upregulation of circ-ABCB10 significantly enhanced the invasiveness and motility of laryngeal cancer cells, while downregulation of circ-ABCB10 was the opposite. Compared with the KLF6 NC group, KLF6 level increased significantly in the KLF6 group, while cell viability, colony formation, scratch healing rate, invasive cell number, and Bcl-2 expression level decreased significantly in the KLF6 group, while apoptosis rate and Bax expression level increased significantly (P < 0.05). KLF6 level in the si-circ-ABCB10+anti-KLF6 group was significantly lower than that in the si-circ-ABCB10+anti-KLF6-NC group (P < 0.05). Meanwhile, the cell activity, colony formation number, cell scratch healing rate, number of invaded cells, and Bcl-2 all indicated an upward trend, while the cell apoptosis rate and Bax expression indicated a downward trend (P < 0.05). CONCLUSION: The expression of circ-ABCB10 in laryngeal carcinoma was significantly higher compared to that in paracancerous tissues. Silencing circ-ABCB10 could significantly inhibit the growth and proliferation of laryngeal adenocarcinoma cells, while overexpression of circ-ABCB10 could significantly promote the growth of laryngeal adenocarcinoma cells, probably by inhibiting KLF6 to enhance the proliferation of laryngeal carcinoma and inhibit apoptosis.