Hsa_circ_0001806 Acts as a ceRNA to Facilitate the Stemness of Colorectal Cancer Cells by Increasing COL1A1

The aberrant expression of circular RNAs (circRNAs) has been identified as a novel trait of cancers. However, the role of circRNAs in colorectal cancer (CRC) remains to be elucidated. Informatic analysis was performed to identify circRNAs in CRC tissues and adjacent tissues. Gain- and loss-of-function experiments were constructed to analyze hsa_circ_001806 roles in CRC cell stemness by sphere-formation, ALDH activity, stemness marker expression and tumor-initiating ability assays. CCK8 cell viability was carried out to evaluate hsa_circ_0001806 roles in CRC cell viability. Luciferase reporter and pull-down assays were used to reveal the underlying mechanisms. Hsa_circ_0001806 was significantly upregulated in CRC tissues and correlated with TNM stage, depth of invasion, lymphatic metastasis and distant metastasis. Hsa_circ_0001806 promoted the stemness of CRC cells, as evident by increasing sphere-formation ability, ALDH1 activity and stemness marker expression while had no effect on cell viability. Mechanistically, the same miR-193-5p-binding sites are shared between hsa_circ_0001806 and COL1A1. Hsa_circ_0001806 upregulates COL1A1 expression in a miR-193-5p-dependent manner, which is essential for hsa_circ_0001806-mediated regulation on CRC cell stemness. CircRNA hsa_circ_0001806 may act as a promising therapeutic target by facilitating the stemness of CRC cells via activating the hsa_circ_0001806/miR-193a-5p/COL1A1 axis.