Clinical Laboratory, The Second Affiliated Hospital of Xi'an Medical University, Xi'an, Shaanxi, China (mainland).
Imaging Department, The Second Affiliated Hospital of Xi'an Medical University, Xi'an, Shaanxi, China (mainland).
Med Sci Monit. 2020 Jul 30;26:e921163. doi: 10.12659/MSM.921163.
BACKGROUND Gastric cancer (GC) remains one of the most fatal digestive cancers in the world; nevertheless, its etiology remains vague. With the development of bioinformatics analysis, numerous circular RNAs (circRNAs) have been found to be dysregulated in GC. However, the functions of a large portion of dysregulated circRNAs in GC need further validation. In this study, we aimed to validate the biological functions of circ_0005556, which was previously identified to be dysregulated in GC. MATERIAL AND METHODS Levels of circRNAs and miRNAs in GC tissues and cells were estimated by qRT-PCR. The target miRNAs of circ_0005556 were predicted by bioinformatics methods. The interplay between circ_0005556 and miR-767-5p was validated by dual-luciferase reporter and circRNA immunoprecipitation assays. The effects of circ_0005556 and miR-767-5p on GC cell viability, apoptosis, migration, and invasion were assessed by MTT, flow cytometry, wound-healing and in vitro transwell experiments, respectively. RESULTS The upregulation of circ_0005556 was validated by qRT-PCR in GC tissues and cells, and a higher circ_0005556 level indicated a poorer prognosis. miR-767-5p was demonstrated to target circ_0005556 in GC cells, and a negative correlation was found between their expression levels in GC tissues. Knockdown of circ_0005556 promoted miR-767-5p expression in GC cells. Knockdown of circ_0005556 was revealed to repress GC cell viability, invasion, and migration and to promote GC cell apoptosis. Moreover, overexpression of miR-767-5p could significantly augment the repressive impacts of circ_0005556 knockdown on GC cell progression in vitro. CONCLUSIONS The in vitro knockdown of circ_0005556 remarkably repressed GC cell progression by increasing the expression of miR-767-5p.
胃癌（GC）仍然是世界上最致命的消化系统癌症之一；然而，其病因仍然不清楚。随着生物信息学分析的发展，已经发现许多环状 RNA（circRNA）在 GC 中失调。然而，GC 中大部分失调 circRNA 的功能仍需要进一步验证。在本研究中，我们旨在验证先前在 GC 中发现失调的 circ_0005556 的生物学功能。
通过 qRT-PCR 评估 GC 组织和细胞中 circRNA 和 miRNA 的水平。通过生物信息学方法预测 circ_0005556 的靶 miRNA。通过双荧光素酶报告和 circRNA 免疫沉淀实验验证 circ_0005556 和 miR-767-5p 之间的相互作用。通过 MTT、流式细胞术、划痕愈合和体外 Transwell 实验分别评估 circ_0005556 和 miR-767-5p 对 GC 细胞活力、凋亡、迁移和侵袭的影响。
通过 qRT-PCR 验证了 circ_0005556 在 GC 组织和细胞中的上调，并且更高的 circ_0005556 水平表明预后较差。miR-767-5p 被证明是 GC 细胞中 circ_0005556 的靶标，并且在 GC 组织中它们的表达水平呈负相关。circ_0005556 的敲低促进了 GC 细胞中 miR-767-5p 的表达。circ_0005556 的敲低被揭示抑制 GC 细胞活力、侵袭和迁移，并促进 GC 细胞凋亡。此外，miR-767-5p 的过表达可以显著增强 circ_0005556 敲低对 GC 细胞体外进展的抑制作用。
体外敲低 circ_0005556 通过增加 miR-767-5p 的表达显著抑制 GC 细胞的进展。
