Wang Guangyao, Yang Haojun
Department of Gastrointestinal Surgery, The Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University, Changzhou, 213000, People's Republic of China.
Cancer Manag Res. 2021 Aug 21;13:6599-6609. doi: 10.2147/CMAR.S323437. eCollection 2021.
Circular RNAs (circRNAs) play critical roles in various types of cancer. The aim of the present study was to investigate the function and underlying mechanism of CircRNA DUSP16 (circDUSP16) in colorectal cancer (CRC) development.
The expression levels of circDUSP16, microRNA-432-5p (miR-432-5p), and E2F transcription factor 6 (E2F6) were measured by RT-qPCR. Cell proliferation, migration, invasion, and apoptosis were investigated by CCK-8, Transwell, and flow cytometry assays. Western blot analysis was used to evaluate the levels of the pro-apoptotic protein (Bax and cleaved-caspase 3) and the anti-apoptotic protein (Bcl-2). Luciferase reporter assay and RIP assay were used to analyze the association between miR-432-5p and circDUSP16 or E2F6. A xenograft tumor model was employed to explore the effect of circDUSP16 on CRC tumor growth in vivo.
CircDUSP16 expression was upregulated in CRC tissues and cell lines. High circDUSP16 expression was correlated with low survival rate. Furthermore, circDUSP16 knockdown repressed cell proliferation, migration, and invasion and induced apoptosis in CRC. CircDUSP16 caused a negative regulation in miR-432-5p expression. In addition, E2F6 expression was elevated in CRC tissues. Inhibition of miR-432-5p promoted the proliferative and metastatic activity of CRC cells and inhibited the induction of apoptosis. Inhibition of E2F6 expression partially abolished the effects caused by miR-432-5p depletion. Moreover, circDUSP16 upregulated E2F6 expression by reducing miR-432-5p expression. Furthermore, circDUSP16 silencing repressed CRC tumor growth in vivo.
The results supported the hypothesis that circDUSP16 knockdown suppressed CRC progression by regulating the miR-432-5p/E2F6 axis, suggesting that the circDUSP16/miR-432-5p/E2F6 network may be a potential therapeutic target for CRC.
环状RNA（circRNAs）在各类癌症中发挥着关键作用。本研究旨在探究环状RNA DUSP16（circDUSP16）在结直肠癌（CRC）发生发展中的功能及潜在机制。
采用RT-qPCR检测circDUSP16、微小RNA-432-5p（miR-432-5p）和E2F转录因子6（E2F6）的表达水平。通过CCK-8、Transwell和流式细胞术检测细胞增殖、迁移、侵袭及凋亡情况。利用蛋白质免疫印迹分析评估促凋亡蛋白（Bax和裂解的半胱天冬酶-3）和抗凋亡蛋白（Bcl-2）的水平。采用荧光素酶报告基因检测和RNA免疫沉淀检测分析miR-432-5p与circDUSP16或E2F6之间的关联。运用异种移植肿瘤模型在体内探究circDUSP16对CRC肿瘤生长的影响。
circDUSP16在CRC组织和细胞系中表达上调。circDUSP16高表达与低生存率相关。此外，circDUSP16敲低可抑制CRC细胞增殖、迁移和侵袭并诱导其凋亡。circDUSP16对miR-432-5p表达起负向调控作用。另外，E2F6在CRC组织中表达升高。抑制miR-432-5p可促进CRC细胞的增殖和转移活性并抑制凋亡诱导。抑制E2F6表达可部分消除miR-432-5p缺失所导致的效应。此外，circDUSP16通过降低miR-432-5p表达上调E2F6表达。而且，circDUSP16沉默在体内可抑制CRC肿瘤生长。
结果支持以下假说，即circDUSP16敲低通过调控miR-432-5p/E2F6轴抑制CRC进展，提示circDUSP16/miR-432-5p/E2F6网络可能是CRC的一个潜在治疗靶点。
