Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China.
Int J Oncol. 2021 Nov;59(5). doi: 10.3892/ijo.2021.5274. Epub 2021 Oct 26.
Diffuse large B‑cell lymphoma (DLBCL) is a common and fatal malignant tumor caused by B‑lymphocytes. Long non‑coding RNA (lncRNA) GAS5 (growth arrest specific 5) has been reported to function as a tumor suppressor gene, and is differentially expressed in DLBCL. The present study aimed to explore the potential mechanisms of action of lncRNA GAS5 in the proliferation of DLBCL cells. The expression levels of GAS5, miR‑18a‑5p and Runt‑related transcription factor 1 (RUNX1) in DLBCL cell lines were detected using reverse transcription‑quantitative polymerase chain reaction, and their effects on cell proliferation, the cell cycle and apoptosis were determined using 5‑ethynyl‑2'‑deoxyuridine assay and flow cytometry. Dual‑luciferase reporter and RNA pull-down assays were used to evaluate the interaction between GAS5 and miR‑18a‑5p, or between miR‑18a‑5p and RUNX1. Chromatin immunoprecipitation assay was used to identify the interaction between RUNX1 and BAX. The expression levels of GAS5 and RUNX1 were downregulated; however, miR‑18a‑5p expression was upregulated in the DLBCL cell lines compared with the normal controls. GAS5 directly interacted with miR‑18a‑5p by acting as a competing endogenous RNA (ceRNA) and reversed the low expression of RUNX1 induced by miR‑18a‑5p. Additionally, the knockdown of RUNX1 reversed the inhibitory effects of GAS5 on the proliferation and cell cycle G1 arrest, and its promoting effects on the apoptosis of OCI‑Ly3 and TMD8 cells. Moreover, RUNX1 enhanced BAX expression by directly binding to the BAX promoter. On the whole, the present study demonstrates that GAS5 functions as a ceRNA, inhibiting DLBCL cell proliferation by sponging miR‑18a‑5p to upregulate RUNX1 expression. These findings may provide a potential therapeutic strategy for DLBCL.
弥漫性大 B 细胞淋巴瘤（DLBCL）是一种由 B 淋巴细胞引起的常见且致命的恶性肿瘤。长链非编码 RNA（lncRNA）GAS5（生长停滞特异性 5）已被报道作为一种肿瘤抑制基因发挥作用，并且在 DLBCL 中存在差异表达。本研究旨在探索 lncRNA GAS5 在 DLBCL 细胞增殖中的潜在作用机制。采用逆转录 - 定量聚合酶链反应检测 DLBCL 细胞系中 GAS5、miR-18a-5p 和 runt 相关转录因子 1（RUNX1）的表达水平，通过 5-乙炔基-2'-脱氧尿苷检测和流式细胞术测定细胞增殖、细胞周期和细胞凋亡的影响。双荧光素酶报告基因和 RNA 下拉实验用于评估 GAS5 与 miR-18a-5p 之间，或 miR-18a-5p 与 RUNX1 之间的相互作用。染色质免疫沉淀实验用于鉴定 RUNX1 与 BAX 之间的相互作用。与正常对照相比，DLBCL 细胞系中 GAS5 的表达下调，而 RUNX1 的表达上调，miR-18a-5p 的表达上调。GAS5 通过作为竞争性内源性 RNA（ceRNA）直接与 miR-18a-5p 相互作用，逆转 miR-18a-5p 诱导的 RUNX1 低表达。此外，RUNX1 的敲低逆转了 GAS5 对 OCI-Ly3 和 TMD8 细胞增殖和细胞周期 G1 期阻滞的抑制作用及其对细胞凋亡的促进作用。此外，RUNX1 通过直接结合 BAX 启动子增强 BAX 表达。总的来说，本研究表明，GAS5 作为 ceRNA 通过海绵吸附 miR-18a-5p 抑制 DLBCL 细胞增殖，从而上调 RUNX1 表达。这些发现可能为 DLBCL 提供一种潜在的治疗策略。
