Department of Radiotherapy, the Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China.
Eur Rev Med Pharmacol Sci. 2019 Feb;23(4):1502-1512. doi: 10.26355/eurrev_201902_17108.
MicroRNAs are endogenous, non-coding, small RNAs that can regulate biological processes. Previous studies have found that microRNA-487a serves as an oncogene. However, the role of microRNA-487a in esophageal cancer (EC) has not been reported. The aim of this investigation was to investigate the biological role of microRNA-487a in EC and its underlying mechanism.
The expression of microRNA-487a in 65 pairs of EC tissues and para-cancerous tissues was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Chi-square test was used to analyze the relationship between microRNA-487a expression with age, sex, clinical stage and distant metastasis of OS patients. Kaplan-Meier survival analysis was conducted to evaluate the correlation between microRNA-487a expression and prognosis of EC patients. Subsequently, microRNA-487a expression in EC cell lines was detected as well. After microRNA-487a knockdown, cell counting kit-8 (CCK-8), EdU and transwell assay were conducted to evaluate the role of microRNA-487a in the biological performances of EC cells, respectively. Meanwhile, the apoptosis of EC cells was determined using flow cytometry. Finally, the interaction between microRNA-487a and p62 was explored by Western blot. Transwell assay was carried out in EC cells co-transfected with p62 overexpression plasmid and si-microRNA-487a.
Compared with para-cancerous tissues, microRNA-487a expression was significantly higher in EC tissues, and the difference was statistically significant. MicroRNA-487a was highly expressed in EC cells as well. Low expression of microRNA-487a was positively correlated with clinical stage, whereas was not correlated with age, sex, lymph node metastasis and distant metastasis of EC patients. Kaplan-Meier survival curves showed that high expression of microRNA-487a was markedly associated with poor prognosis of EC. The knockdown of microRNA-487a significantly inhibited proliferative, migratory and invasive abilities of EC cells but induced cell apoptosis. Western blot results showed that the protein expression of p62 was remarkably upregulated after microRNA-478a knockdown in EC cells. Transwell assay demonstrated that co-transfection with overexpression plasmid of p62 and si-microRNA-487a in EC cells markedly decreased invasive and migratory abilities.
MicroRNA-487a is highly expressed in EC and is closely correlated with clinical stage and poor prognosis of EC. Our findings confirm that microRNA-487a promotes malignant progression of EC by regulating p62 expression.
MicroRNAs 是内源性的非编码小分子 RNA，可以调节生物过程。先前的研究发现 microRNA-487a 作为一种癌基因。然而，microRNA-487a 在食管癌（EC）中的作用尚未报道。本研究旨在探讨 microRNA-487a 在 EC 中的生物学作用及其潜在机制。
采用实时定量聚合酶链反应（qRT-PCR）检测 65 对 EC 组织和癌旁组织中 microRNA-487a 的表达。卡方检验分析 microRNA-487a 表达与 OS 患者年龄、性别、临床分期和远处转移的关系。Kaplan-Meier 生存分析评估 microRNA-487a 表达与 EC 患者预后的相关性。随后检测 EC 细胞系中 microRNA-487a 的表达。microRNA-487a 敲低后，通过细胞计数试剂盒-8（CCK-8）、EdU 和 Transwell 测定分别评估 microRNA-487a 在 EC 细胞生物学行为中的作用。同时，采用流式细胞术检测 EC 细胞的凋亡。最后，通过 Western blot 探讨 microRNA-487a 与 p62 之间的相互作用。在共转染 p62 过表达质粒和 si-microRNA-487a 的 EC 细胞中进行 Transwell 测定。
与癌旁组织相比，EC 组织中 microRNA-487a 的表达明显升高，差异具有统计学意义。EC 细胞中也高表达 microRNA-487a。microRNA-487a 的低表达与 EC 患者的临床分期呈正相关，而与年龄、性别、淋巴结转移和远处转移无关。Kaplan-Meier 生存曲线显示，microRNA-487a 的高表达与 EC 的不良预后显著相关。microRNA-487a 敲低后可显著抑制 EC 细胞的增殖、迁移和侵袭能力，但诱导细胞凋亡。Western blot 结果显示，EC 细胞中 microRNA-487a 敲低后 p62 蛋白表达明显上调。Transwell 实验表明，在 EC 细胞中共转染 p62 过表达质粒和 si-microRNA-487a 可显著降低细胞的侵袭和迁移能力。
microRNA-487a 在 EC 中高表达，与 EC 的临床分期和不良预后密切相关。本研究证实，microRNA-487a 通过调节 p62 的表达促进 EC 的恶性进展。
