Colorectal cancer (CRC) is a malignant cancer with an increasing incidence. Circular RNA (circRNA) is recently found to participate in the regulation of CRC progression. However, the role of circ_0007031 in CRC malignant progression remains elusive. 50 CRC patients were implicated in this study. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the RNA expression of circ_0007031, microRNA-485-3p (miR-485-3p) and maternal embryonic leucine zipper kinase (MELK). Western blot analysis was conducted to determine protein expression. Cell viability and proliferation were demonstrated by cell counting kit-8 and 5-Ethynyl-29-deoxyuridine (EdU) assays, respectively. Cell cycle and apoptosis were investigated by flow cytometry analysis. The interaction among circ_0007031, miR-485-3p and MELK was predicted by online databases, and identified by dual-luciferase reporter assay. Mouse model assay was conducted to reveal the effect of circ_0007031 on tumor formation in vivo. Circ_0007031 and MELK expression were obviously increased, while miR-485-3p expression was decreased in CRC tissues and cells compared with normal colorectal tissues or cells. Circ_0007031 knockdown repressed proliferation, whereas induced cell arrest at G0/G1 phase and apoptosis. On the opposite, circ_0007031 overexpression promoted cell proliferation and induced cell arrest at S phase. Additionally, miR-485-3p inhibitors attenuated circ_0007031 silencing-mediated CRC cell malignancy. MiR-485-3p was unveiled to regulate CRC cell processes via targeting MELK. Circ_0007031 controlled MELK expression via interacting with miR-485-3p. Furthermore, circ_0007031 contributed to tumor formation in vivo. Circ_0007031 knockdown repressed CRC malignant progression by reducing MELK expression through associating with miR-485-3p, suggesting that circ_0007031 was a potential target for the therapy of CRC.

结直肠癌（CRC）是一种发病率不断增加的恶性肿瘤。最近发现环状 RNA (circRNA) 参与调节 CRC 进展。然而，circ_0007031 在 CRC 恶性进展中的作用仍然难以捉摸。本研究涉及 50 名 CRC 患者。进行定量实时聚合酶链反应 (qRT-PCR) 以检测 circ_0007031、microRNA-485-3p (miR-485-3p) 和母体胚胎亮氨酸拉链激酶 (MELK) 的 RNA 表达。进行蛋白质印迹分析以确定蛋白质表达。细胞活力和增殖分别通过细胞计数 kit-8 和 5-Ethynyl-29-deoxyuridine (EdU) 测定来证明。通过流式细胞术分析研究细胞周期和细胞凋亡。circ_0007031、miR-485-3p和MELK之间的相互作用是通过在线数据库预测的，并通过双荧光素酶报告基因测定法鉴定。进行小鼠模型试验以揭示 circ_0007031 对体内肿瘤形成的影响。与正常结直肠组织或细胞相比，CRC组织和细胞中Circ_0007031和MELK表达明显升高，而miR-485-3p表达降低。Circ_0007031 敲低抑制增殖，而诱导细胞停滞在 G0/G1 期和细胞凋亡。相反，circ_0007031 过表达促进细胞增殖并诱导细胞停滞在 S 期。此外，miR-485-3p 抑制剂减弱了 circ_0007031 沉默介导的 CRC 细胞恶性肿瘤。MiR-485-3p 被发现可通过靶向 melk 来调节 CRC 细胞过程。Circ_0007031 通过与 miR-485-3p 相互作用来控制 MELK 的表达。此外，circ_0007031 有助于体内肿瘤的形成。