Zhang Zhen, Wu Honglei, Chen Zhaosheng, Li Guangchun, Liu Bin
Department of Gastroenterology, The Second Hospital of Shandong University, No. 247 Beiyuan Street, Jinan, 250033 Shandong China.
Cancer Cell Int. 2020 Jan 23;20:25. doi: 10.1186/s12935-020-1106-5. eCollection 2020.
Circular RNAs (circRNAs) which are shown as a class of RNAs exhibit the importance in the regulation of gene expression and the development of biological process. However, the expression profile and molecular mechanism of circRNA ATXN7 (circATXN7) is still mostly uncertain in gastric cancer (GC).
qRT-PCR analysis was performed to detect the expression of circATXN7, miR-4319 and ENTPD4 in GC tissues and cells. CCK-8, colony formation, EdU, flow cytometry, TUNEL and transwell assays were conducted to assess the effect of circATXN7 or miR-4319 on cell proliferation, apoptosis and invasion. In vivo assays were utilized to further analyze the function of circATXN7 on the tumorigenesis and progression of GC. The interaction between miR-4319 and circATXN7 (or ENTPD4) was verified using luciferase reporter and RNA pull-down assays.
The results showed an upregulated circATXN7 expression in GC tissues and cell lines. Besides, silenced circATXN7 hampered the proliferation and invasion as well as promoted the apoptosis in GC cells. Moreover, low expression of miR-4319 was found in GC. It was determined that circATXN7 acted as a sponge for miR-4319 and had a negative association with miR-4319. We also found that miR-4319 upregulation restrained GC cell proliferation and migration whereas enhanced apoptosis. Subsequently, ENTPD4, the target gene of miR-4319, was found overexpressed in GC. Additionally, it was negatively correlated with miR-4319 whereas positively associated with circATXN7. In vivo experiments, circATXN7 silence was confirmed to inhibit GC tumor growth.
CircATXN7 promoted GC development through sponging miR-4319 and regulating ENTPD4, which identified circATXN7 as a new biomarker in GC.
环状RNA（circRNAs）作为一类RNA，在基因表达调控和生物过程发育中具有重要作用。然而，circRNA ATXN7（circATXN7）在胃癌（GC）中的表达谱和分子机制仍大多未知。
采用qRT-PCR分析检测circATXN7、miR-4319和ENTPD4在GC组织和细胞中的表达。进行CCK-8、集落形成、EdU、流式细胞术、TUNEL和Transwell实验，以评估circATXN7或miR-4319对细胞增殖、凋亡和侵袭的影响。利用体内实验进一步分析circATXN7对GC肿瘤发生和进展的作用。通过荧光素酶报告基因和RNA下拉实验验证miR-4319与circATXN7（或ENTPD4）之间的相互作用。
结果显示circATXN7在GC组织和细胞系中表达上调。此外，沉默circATXN7可抑制GC细胞增殖和侵袭，并促进其凋亡。此外，在GC中发现miR-4319表达较低。确定circATXN7作为miR-4319的海绵，与miR-4319呈负相关。我们还发现，miR-4319上调可抑制GC细胞增殖和迁移，同时增强凋亡。随后，发现miR-4319的靶基因ENTPD4在GC中过表达。此外，它与miR-4319呈负相关，与circATXN7呈正相关。在体内实验中，证实circATXN7沉默可抑制GC肿瘤生长。
CircATXN7通过吸附miR-4319并调节ENTPD4促进GC发展，这表明circATXN7是GC中的一种新生物标志物。
