Circular RNA circ0000601 suppresses colorectal cancer cell proliferation through miR-31-5p and its target NUMB

Objective To investigate the effect of circ0000601 on the proliferation of colorectal cancer cell and its possible mechanism. Methods High-throughput circRNA chip was used to screen circRNA gene between colorectal cancer tissues and paired normal tissues. PCR was used to detect the relative expression of circ0000601 in colorectal cancer tissues, paired normal tissues and colorectal cancer cell lines. circ0000601 expression was upregulated through transfecting with circ0000601 mimic and cell proliferation was analyzed by CCK-8 assay. Bioinformatics prediction software was used to analyze circ0000601 target miRNA and luciferasw reporter system was used to verificate circ0000601 target miRNA. The expression of miR-31-5p was down-regulated through transfection of miR-31-5p inhibitor and cell proliferation was analyzed by CCK-8 assay. miRBase was used to predict the target gene of miR-31-5p and Luciferase reporter assay was used to confirm that NUMB was a direct target of miR-31-5p. The expression of miR-31-5p and NUMB protein expression in colorectal cancer cells was detected by Western blotting. circ0000601 expression was upregulated in colorectal cancer cells and NUMB mRNA expression in colorectal cancer cells were detected. Results T-test and Kruskal-Wallis test were used in data analysis. The expression of circ0000601 was lower in colorectal cancer tissues than paired normal tissues and overexpression of circ0000601 reduced colorectal cancer cell proliferation. miR-31-5p was identified and validated to be a target miRNA of circ0000601. The knockdown of miR-31-5p suppressed the proliferation of colorectal cancer cells. Luciferase reporter assay confirmed that NUMB was a direct target of miR-31-5p. The protein level of NUMB was decreased by miR-31-5p Mimic. Also up-regulation of circ0000601 could increase the expression of NUMB mRNA. Conclusion circ0000601 can inhibit colorectal cancer cell proliferation by circ0000601/miR-31-5p/NUMB pathway, therefore, circ0000601 acts as a promising therapeutic target for colorectal cancer patients. Key words: Circular RNA; Colorectal cancer