Cervical cancer has been shown to be one of the leading cancer-related death causes all over the world. Several studies demonstrates that hsa_circ_0023404 plays a crucial role in progression of cervical cancer; however, the detailed mechanism of hsa_circ_0023404 regulating cervical cancer metastasis and chemoresistance remains unclear.

We used RT-qPCR and westernblot approach to detect expression levels of various genes in cervical tumors and cancer cells. To examine invasion and lymphatic vessel formation of Human Dermal Lymphatic Endothelial Cells (HDLEC), transwell invasion assay and lymphatic vessel assay were utilized in the presence of conditioned medium of HeLa and SiHa cells. To examine direct interaction between hsa_circ_0023404 and miR-5047, bioinformatic analysis and luciferase reporter assay were used. Besides, MTT and flow cytometry analysis were conducted to assess cell viability and apoptosis rate of HeLa cell.

hsa_circ_0023404 knockdown attenuates invasion of cervical cancer cells and lymphatic vessel formation of HDLEC cells. hsa_circ_0023404 directly interacted with miR-5047. Moreover, miR-5047 inhibitor-transfected HeLa and SiHa cells enhanced invasion and lymphatic vessel formation of HDLEC cells. More interestingly, we confirmed that hsa_circ_0023404 knockdown and miR-5047 mimic downregulated the expression levels of VEGFA. The functional rescue experiments indicated VEGFA acted as key factor for hsa_circ_0023404- and miR-5047-regulated invasion and lymphatic vessel formaion. Ultimately, hsa_circ_0023404 and VEGFA were upregulated and showed positive correlation in cervical tumors, while miR-5047 was downregulated and showed negative correlation with hsa_circ_0023404 and VEGFA. On the other hand, autophagy-associated genes (Beclin1 and p62) were dysregulated in hsa_circ_0023404 depleted and overexpressed HeLa cells. hsa_circ_0023404 knockdown inhibited cell viability of cells, which was obviously abolished by autophagy inhibitor 3-MA in the presence of various concentrations of Cisplatin. Consistently, apoptosis rate was remarkably elevated in hsa_circ_0023404 depleted cells and diminished in hsa_circ_0023404 overexpressed cells under treatment of 2 μg/ml Cisplatin.

Here, we reveal a novel role of hsa_circ_0023404 for cervical cancer metastasis and chemoresistance by regulating miR-5047. Our findings help understand mechanism underlying cervical cancer and development of therapeutical approaches for treating cervical cancer.