Earlier studies have shown that circular RNA (circRNA) expression is closely related to the malignant progression of cancer, but the role of circ-DONSON in gastric cancer (GC) has not been fully elucidated. The expression of circ-DONSON, miR-149-5p and lactate dehydrogenase A (LDHA) was measured via qRT-PCR. CCK8 assay was used to assess cell viability, and colony formation assay was performed to detect the number of colonies and the radiosensitivity of cells. Besides, flow cytometry, transwell assay and tube formation assay were employed to determine cell apoptosis, migration, invasion and angiogenesis. Western blot analysis was used to assess the protein expression. The interaction between miR-149-5p and circ-DONSON or LDHA was confirmed by dual-luciferase reporter assay. The influence of circ-DONSON on GC tumor growth in vivo was explored through constructing mice xenograft models. Our results suggested that circ-DONSON was highly expressed in GC tissues and cells. Loss-functional assay results confirmed that silenced circ-DONSON could inhibit the proliferation, metastasis and angiogenesis, while enhance the apoptosis and radiosensitivity of GC cells. In terms of mechanism, circ-DONSON could sponge miR-149-5p, which could target LDHA in GC. MiR-149-5p inhibitor or LDHA overexpression could reverse the suppression effect of circ-DONSON knockdown on GC progression. Additionally, our results also suggested that circ-DONSON silencing could restrain the tumor growth of GC in vivo. These results demonstrated that circ-DONSON could facilitate GC progression by increasing LDHA expression via sponging miR-149-5p, indicating that circ-DONSON might be a novel biomarker for GC treatment.

早期研究表明环状RNA（circRNA）的表达与癌症的恶性进展密切相关，但circ-DONSON在胃癌（GC）中的作用尚未完全阐明。通过 qRT-PCR 测量 circ-DONSON、miR-149-5p 和乳酸脱氢酶 A (LDHA) 的表达。CCK8测定用于评估细胞活力，并进行集落形成测定以检测集落数量和细胞的放射敏感性。此外，还采用流式细胞仪、transwell 试验和管形成试验测定细胞凋亡、迁移、侵袭和血管生成。蛋白质印迹分析用于评估蛋白质表达。miR-149-5p 与 circ-DONSON 或 LDHA 之间的相互作用通过双荧光素酶报告基因测定得到证实。通过构建小鼠异种移植模型探讨了circ-DONSON对体内GC肿瘤生长的影响。我们的结果表明circ-DONSON在GC组织和细胞中高度表达。损失功能测定结果证实沉默的circ-DONSON可以抑制GC细胞的增殖、转移和血管生成，同时增强GC细胞的凋亡和放射敏感性。就机制而言，circ-DONSON 可以海绵化 miR-149-5p，从而靶向 GC 中的 LDHA。MiR-149-5p 抑制剂或 LDHA 过表达可以逆转 circ-DONSON 敲低对 GC 进展的抑制作用。此外，我们的结果还表明，circ-DONSON 沉默可以抑制体内 GC 的肿瘤生长。这些结果表明，circ-DONSON 可以通过海绵化 miR-149-5p 增加 LDHA 表达来促进 GC 进展，