The Operating Room, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
Nutrition Department, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
J Cell Biochem. 2019 Apr;120(4):6145-6153. doi: 10.1002/jcb.27902. Epub 2018 Oct 25.
The long noncoding RNA MNX1-AS1 has been reported to facilitate the progression of glioblastoma and ovarian cancer. Nevertheless, the biological roles and underlying mechanisms of MNX1-AS1 in colon adenocarcinoma have not been studied until now. In the current study, MNX1-AS1 was upregulated in colon adenocarcinoma. JASPAR prediction tool showed that E2F1 could bind to the promoter region of MNX1-AS1. The chromatin immunoprecipitation assay and luciferase reporter assay were used to verify the interactions between MNX1-AS1 and E2F1. Then functional assays revealed that downregulation of MNX1-AS1 decreased cell proliferation, migration, and invasion in colon adenocarcinoma, but upregulation of E2F1 reversed the effects. Moreover, subcellular fractionation assay manifested that MNX1-AS1 was enriched in the cytoplasm of colon adenocarcinoma cells, thus we speculated whether MNX1-AS1 could function as a competing endogenous RNA (ceRNA) to play roles in colon adenocarcinoma. Bioinformatics analysis and luciferase reporter assay indicated that MNX1-AS1 could sponge microRNA-218-5p (miR-218-5p). Furthermore, we discovered that SEC61A1 was downstream target of miR-218-5p, and MNX1-AS1 acted as a ceRNA to upregulate the expression of SEC61A1 through sponging miR-218-5p. Finally, rescue assays confirmed that MNX1-AS1 facilitated the progression of colon adenocarcinoma through regulating miR-218-5p/SEC61A1 axis. Taken together, we concluded that E2F1-mediated MNX1-AS1-miR-218-5p-SEC61A1 feedback loop contributed to the progression of colon adenocarcinoma.
长链非编码 RNA MNX1-AS1 已被报道可促进胶质母细胞瘤和卵巢癌的进展。然而，MNX1-AS1 在结肠腺癌中的生物学作用和潜在机制至今尚未研究。在本研究中，MNX1-AS1 在结肠腺癌中上调。JASPAR 预测工具表明，E2F1 可以结合 MNX1-AS1 的启动子区域。染色质免疫沉淀测定和荧光素酶报告基因测定用于验证 MNX1-AS1 和 E2F1 之间的相互作用。然后，功能测定表明下调 MNX1-AS1 可降低结肠腺癌中的细胞增殖、迁移和侵袭，而上调 E2F1 可逆转这些作用。此外，亚细胞分馏测定表明 MNX1-AS1 富含在结肠腺癌细胞的细胞质中，因此我们推测 MNX1-AS1 是否可以作为竞争性内源 RNA (ceRNA) 在结肠腺癌中发挥作用。生物信息学分析和荧光素酶报告基因测定表明 MNX1-AS1 可以海绵 microRNA-218-5p (miR-218-5p)。此外，我们发现 SEC61A1 是 miR-218-5p 的下游靶标，MNX1-AS1 通过海绵 miR-218-5p 作为 ceRNA 上调 SEC61A1 的表达。最后，挽救测定证实，MNX1-AS1 通过调节 miR-218-5p/SEC61A1 轴促进结肠腺癌的进展。总之，我们得出结论，E2F1 介导的 MNX1-AS1-miR-218-5p-SEC61A1 反馈环促进了结肠腺癌的进展。
