Department of Gastrointestinal Surgery, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital of Sun Yat-sen University, Supported by National Key Clinical Discipline, No.26 YuanCun 2nd Heng Road, Guangdong Province, 510655, Guangzhou City, China.
Department of General Surgery, Shenzhen Hospital of Southern Medical University, Shenzhen City, Guangdong Province, China.
J Exp Clin Cancer Res. 2021 Jul 12;40(1):227. doi: 10.1186/s13046-021-02029-y.
Colorectal cancer (CRC) is a common malignant tumor. Circular RNAs (circRNAs) have been reported to take part in the progression of CRC. However, the functions of circ_0084615 in CRC development are still undefined. In this study, we aimed to explore the functions and underlying mechanisms of circ_0084615 in CRC.
qRT-PCR, western blot assay and IHC assay were utilized for the levels of circ_0084615, miR-599, ONECUT2 or EIF4A3. 5-ethynyl-2'-deoxyuridine (EdU) assay and colony formation assay were conducted for cell proliferation ability. Wound-healing assay and transwell assay were applied to evaluate cell migration and invasion. Tube formation assay was used to analyze angiogenesis ability. RNA immunoprecipitation (RIP) assay, RNA pull down assay and dual-luciferase reporter assay were used to analyze the relationships of circ_0084615, miR-599, ONECUT2 and EIF4A3. Murine xenograft model assay was employed for the role of circ_0084615 in vivo.
Circ_0084615 was elevated in CRC tissues and was linked to TNM stages, lymph node metastasis, differentiation and overall survival rate. Circ_0084615 knockdown inhibited CRC cell proliferation, migration, invasion and angiogenesis in vitro and hampered tumorigenesis in vivo. Circ_0084615 sponged miR-599 and miR-599 inhibition reversed circ_0084615 knockdown-mediated effects on CRC cell growth, motility and angiogenesis. ONECUT2 was identified as the target gene of miR-599. ONECUT2 overexpression recovered the effects of miR-599 on CRC malignant behaviors. Additionally, EIF4A3 induced circ_0084615 expression.
EIF4A3-induced circ_0084615 played an oncogenic role in CRC development via miR-599/ONECUT2 axis.
结直肠癌（CRC）是一种常见的恶性肿瘤。环状 RNA（circRNA）已被报道参与 CRC 的进展。然而，circ_0084615 在 CRC 发展中的功能仍未确定。在本研究中，我们旨在探讨 circ_0084615 在 CRC 中的功能和潜在机制。
利用 qRT-PCR、western blot 检测和免疫组织化学检测 circ_0084615、miR-599、ONECUT2 或 EIF4A3 的水平。5-乙炔基-2'-脱氧尿苷（EdU）检测和集落形成检测用于评估细胞增殖能力。划痕愈合检测和 Transwell 检测用于评估细胞迁移和侵袭能力。管形成检测用于分析血管生成能力。RNA 免疫沉淀（RIP）检测、RNA 下拉检测和双荧光素酶报告基因检测用于分析 circ_0084615、miR-599、ONECUT2 和 EIF4A3 之间的关系。使用小鼠异种移植模型检测 circ_0084615 在体内的作用。
circ_0084615 在 CRC 组织中上调，并与 TNM 分期、淋巴结转移、分化和总生存率相关。circ_0084615 敲低抑制 CRC 细胞在体外的增殖、迁移、侵袭和血管生成，并阻碍体内肿瘤发生。circ_0084615 海绵吸附 miR-599，miR-599 抑制逆转了 circ_0084615 敲低对 CRC 细胞生长、迁移和血管生成的影响。ONECUT2 被鉴定为 miR-599 的靶基因。ONECUT2 的过表达恢复了 miR-599 对 CRC 恶性行为的影响。此外，EIF4A3 诱导 circ_0084615 的表达。
EIF4A3 诱导的 circ_0084615 通过 miR-599/ONECUT2 轴在 CRC 发展中发挥致癌作用。
