Zheng X, et al. Eur Rev Med Pharmacol Sci 2020.
OBJECTIVE: Growing evidence has revealed that circular RNAs (circRNAs) play important roles in the development of cancers, including colorectal cancer (CRC). In this study, we mainly focused on the expression of circ_0056618 and potential functions of circ_0056618 in CRC patients.
PATIENTS AND METHODS: RT-PCR was performed to detect circ_0056618 and miR-206 expressions in CRC tissues and adjacent non-tumor tissues. Correlation analysis was used to analyze the correlation between circ_0056618 and miR-206. Kaplan-Meier method was conducted to analyze the overall survival (OS) for CRC patients. Moreover, CCK-8 assay was used to measure cell proliferation ability and transwell assay was performed to detect cell migration ability. Besides, tube formation assay was performed to measure cell angiogenesis capacity. Western blot (WB) was performed to measure protein levels of tissues samples and CRC cell lines. Notably, the Luciferase reporter assay was performed to prove the binding sites in circ_0056618 with miR-206, miR-206 with CXCR4 and VEGF-A.
RESULTS: We found that circ_0056618 was elevated in CRC tumor tissues and CRC cell lines, which was related to poor diagnosis for CRC patients. MiR-206 was reduced in CRC tissues, which was negatively related with circ_0056618. Protein levels of CXCR4 and VEGF-A were elevated in CRC tumor tissues, which were negatively related with miR-206. Circ_0056618 inhibition inhibited proliferation, angiogenesis and migration of HT29 cells, and repressed protein levels of Cyclin D1, VEGF-A and N-cadherin and increased E-cadherin. Notably, Luciferase reporter assay indicated that circ_0056618 could sponge with miR-206, which could directly target at CXCR4 and VEGF-A. Finally, we proved a pathway that circ_0056618 promoted cell proliferation, migration and angiogenesis through sponging with miR-206 and removing the repressing effects of miR-206, thereby upregulating CXCR4 and VEGF-A in CRC.
CONCLUSIONS: Above all, this study revealed that circ_0056618 was increased in CRC tissues, which was related with the poor OS of CRC patients. We found that circ_0056618 could promote cell proliferation, migration and angiogenesis through sponging with miR-206 and upregulating CXCR4 and VEGF-A in CRC, which might provide a novel potential therapeutic target for treating CRC.