Circ_0006174 promotes colorectal cancer progression by sponging microRNA-142-3p and regulating X-linked inhibitor of apoptosis expression.

Background: Circular RNAs (circRNAs) are crucial in the regulation of gene expression and biological processes. However, in colorectal cancer, the expression characteristics and biological function of circRNA_0006174 (circ_0006174) is not fully understood. This work is aimed to investigate the biological function of circ_0006174 in colorectal cancer and its molecular mechanism.

Methods: Circ_0006174, microRNA-142-3p and X-linked inhibitor of apoptosis expression levels were detected in colorectal cancer tissues and cells using quantitative real-time polymerase chain reaction analysis or Western blot. The effects of circ_0006174 on colorectal cancer cell proliferation, apoptosis, migration and invasion were detected using the cell counting kit-8 method, bromodeoxyuridine experiments, flow cytometry analysis and Transwell experiments. The targeting relationship among circ_0006174, microRNA-142-3p and X-linked inhibitor of apoptosis was analysed by bioinformatics prediction, dual-luciferase reporter experiment and RNA immunoprecipitation experiment.

Results: Circ_0006174 was up-regulated in colorectal cancer tissues as well as in cell lines, and its high expression was remarkably associated with enlarged tumour volume and advanced tumour, node, metastasis stage of the patients. Circ_0006174 overexpression enhanced colorectal cancer cell proliferation, migration and invasion, and inhibited colorectal cancer cell apoptosis; while knocking down circ_0006174 caused the opposite effects. Circ_0006174 directly targeted and negatively regulated microRNA-142-3p expression, and X-linked inhibitor of apoptosis, a target gene of microRNA-142-3p, could be indirectly and positively modulated by circ_0006174.

Conclusion: Circ_0006174 facilitates colorectal cancer cell proliferation, migration and invasion, and represses colorectal cancer cell apoptosis by regulating microRNA-142-3p/X-linked inhibitor of apoptosis axis.