The Second Department of Orthopaedics, The First People's Hospital of Xianyang, Xianyang 712000, Shaanxi Province, China.
Department of Orthopedics, Shaanxi Provincial People's Hospital, The Third Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710068, Shaanxi Province, China.
Aging (Albany NY). 2021 Dec 14;13(23):25484-25495. doi: 10.18632/aging.203769.
Osteosarcoma (OS) is one of the most common primary bone tumors in children and adolescents. However, the molecular mechanism of OS tumorigenesis is still little known. Circular RNA (circRNA) is a key player in the progression of many cancers. This study is performed to decipher the role and mechanism of circ_0008259 in the progression of OS.
A differentially expressed circRNA, circ_0008259, was screened out by analyzing the expression profile of circRNA in OS tissue. Circ_0008259, miR-21-5p and programmable cell death 4 (PDCD4) mRNA expression levels in OS tissues and cells were detected by qRT-PCR. Cell viability, metastatic potential and apoptosis were evaluated by cell counting kit-8 assay, Transwell and flow cytometry. The targeting relationship between circ_0008259 and miR-21-5p, and miR-21-5p and PDCD4 mRNA was analyzed and probed by bioinformatics analysis and dual-luciferase reporter assay, RNA-binding protein immunoprecipitation assay and RNA-pull down assay. The regulatory effects of circ_0008259 and miR-21-5p on PDCD4 protein expression in OS cells were detected by Western blot assay.
Circ_0008259 expression and PDCD4 expression were down-regulated and miR-21-5p expression was elevated in the OS tissues and cells. Functional experiments showed that circ_0008259 overexpression significantly inhibited the proliferation and metastatic potential of OS cells and promoted the apoptosis. Besides, PDCD4 was validated as the target gene of miR-21-5p, and circ_0008259 could competitively bind to miR-21-5p, thus up-regulating PDCD4 expression in OS cells.
Circ_0008259 suppresses OS progression via regulating miR-21-5p/PDCD4 axis.
骨肉瘤（OS）是儿童和青少年中最常见的原发性骨肿瘤之一。然而，OS 肿瘤发生的分子机制仍知之甚少。环状 RNA（circRNA）是许多癌症进展的关键因素。本研究旨在破译 circ_0008259 在 OS 进展中的作用和机制。
通过分析 OS 组织中 circRNA 的表达谱，筛选出差异表达的 circRNA，circ_0008259。通过 qRT-PCR 检测 OS 组织和细胞中 circ_0008259、miR-21-5p 和程序性细胞死亡 4（PDCD4）mRNA 的表达水平。通过细胞计数试剂盒-8 测定、Transwell 和流式细胞术评估细胞活力、转移潜能和细胞凋亡。通过生物信息学分析和双荧光素酶报告基因测定、RNA 结合蛋白免疫沉淀测定和 RNA 下拉测定分析和验证 circ_0008259 与 miR-21-5p 以及 miR-21-5p 和 PDCD4 mRNA 的靶向关系。通过 Western blot 测定检测 circ_0008259 和 miR-21-5p 对 OS 细胞中 PDCD4 蛋白表达的调节作用。
circ_0008259 表达和 PDCD4 表达下调，miR-21-5p 表达上调，在 OS 组织和细胞中。功能实验表明，circ_0008259 过表达显著抑制 OS 细胞的增殖和转移潜能，促进细胞凋亡。此外，PDCD4 被验证为 miR-21-5p 的靶基因，circ_0008259 可以竞争性结合 miR-21-5p，从而上调 OS 细胞中 PDCD4 的表达。
circ_0008259 通过调节 miR-21-5p/PDCD4 轴抑制 OS 进展。
