Background

Recent studies have pinpointed that circular RNA (circRNA) regulates diverse cellular processes in oesophageal squamous cell carcinoma (ESCC). However, the role of circ_0000277 in ESCC progression remains unclear.

Methods

RNA levels of circ_0000277, microRNA-1294 (miR-1294) and dishevelled segment polarity protein 3 (DVL3) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Protein expression was analyzed by Western blotting analysis or immunohistochemistry assay. Cell viability and cell proliferation were investigated by a cell counting kit-8 assay and 5-Ethynyl-2’-deoxyuridine (EdU) assay. Cell migration and invasion were assessed by wound-healing assay and transwell invasion assay. Dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assays were conducted to identify the associations among circ_0000277, miR-1294 and DVL3. The xenograft mouse model assay was used to evaluate the effect of circ_0000277 on tumour’s tumorigenesis.

Results

Circ_0000277 and DVL3 expressions were significantly upregulated, while miR-1294 was downregulated in ESCC tissues and cells compared with control groups. Additionally, high expression of circ_0000277 was associated with poor prognosis of ESCC patients. Circ_0000277 overexpression promoted ESCC cell proliferation, migration and invasion; however, depletion of circ_0000277 displayed the opposite effects. Noticeably, circ_0000277 acted as a miR-1294 sponge, and regulated ESCC cell malignancy through interaction with miR-1294. DVL3 was identified as a target of miR-1294, and its overexpression attenuated miR-1294-induced effects in ESCC cells. Besides, circ_0000277 induced DVL3 expression by sponging miR-1294. Circ_0000277 knockdown suppressed tumour formation in vivo.

Conclusion

Circ_0000277 promoted ESCC malignant progression through the miR-1294/DVL3 pathway.

Highlights

1. 1.

   Circ_0000277 expression was upregulated in ESCC tissues and cells.

2. 2.

   Circ_0000277 contributed to ESCC cell proliferation, migration and invasion.

3. 3.

   Circ_0000277 induced DVL3 expression through sponging miR-1294.

中文翻译：

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Circ_0000277通过miR-1294依赖的DVL3调节促进食管鳞状细胞癌的恶性进展

背景

最近的研究指出，环状 RNA (circRNA) 调节食管鳞状细胞癌 (ESCC) 中的多种细胞过程。然而，circ_0000277 在 ESCC 进展中的作用仍不清楚。

方法

通过定量实时聚合酶链式反应 (qRT-PCR) 检测 circ_0000277、microRNA-1294 (miR-1294) 和蓬乱片段极性蛋白 3 (DVL3) 的 RNA 水平。通过蛋白质印迹分析或免疫组织化学测定来分析蛋白质表达。通过细胞计数试剂盒 8 测定和 5-乙炔基-2'-脱氧尿苷 (EdU) 测定研究细胞活力和细胞增殖。通过伤口愈合测定和跨孔侵袭测定评估细胞迁移和侵袭。进行双荧光素酶报告基因、RNA 免疫沉淀和 RNA Pull-down 测定，以确定 circ_0000277、miR-1294 和 DVL3 之间的关联。使用异种移植小鼠模型测定来评估circ_0000277对肿瘤发生的影响。

结果

与对照组相比，ESCC组织和细胞中Circ_0000277和DVL3表达显着上调，而miR-1294表达下调。此外，circ_0000277的高表达与ESCC患者的不良预后相关。 Circ_0000277过表达促进ESCC细胞增殖、迁移和侵袭；然而，circ_0000277 的耗尽显示出相反的效果。值得注意的是，circ_0000277充当miR-1294海绵，并通过与miR-1294相互作用调节ESCC细胞恶性肿瘤。 DVL3 被确定为 miR-1294 的靶标，其过度表达减弱了 miR-1294 在 ESCC 细胞中诱导的作用。此外，circ_0000277通过海绵miR-1294诱导DVL3表达。 Circ_0000277 敲低抑制体内肿瘤形成。

结论

Circ_0000277通过miR-1294/DVL3途径促进ESCC恶性进展。

强调

1. 1.

   Circ_0000277 表达在 ESCC 组织和细胞中上调。

2. 2.

   Circ_0000277 有助于食管鳞癌细胞的增殖、迁移和侵袭。

3. 3.

   Circ_0000277 通过海绵 miR-1294 诱导 DVL3 表达。