Long non-coding RNA NCK1-AS1 functions as a ceRNA to regulate cell viability and invasion in esophageal squamous cell carcinoma via microRNA-133b/ENPEP axis

This study is designed to explore the role of long non-coding RNAs (lncRNAs) NCK1-AS1 in proliferative and invasive activities of esophageal squamous cell carcinoma (ESCC) cells by binding to microRNA-133b (miR-133b) to regulate ENPEP. Differentially expressed lncRNAs, miRs, genes and their targeting relationships were screened on ESCC-related gene expression datasets GSE17351 and GSE6188. The targeting relationships among NCK1-AS1, miR-133b, and ENPEP were verified using functional assays. Loss- and gain- of function assays were carried out to examine the roles of NCK1-AS1, miR-133b, and ENPEP in ESCC cell proliferative, invasive, migrative and apoptotic abilities as well as tumorigenesis <i>in vivo</i>. Elevated NCK1-AS1 and ENPEP but reduced miR-133b expression were found in ESCC. NCK1-AS1 knockdown or miR-133b overexpression inhibited the malignant properties of ESCC cells as well as tumorigenesis <i>in vivo</i>. NCK1-AS1 regulated the ENPEP expression by competitively binding to miR-133b. ENPEP overexpression reversed inhibition of NCK1-AS1 knockdown on the function of ESCC cells. This study provides evidence that silencing NCK1-AS1 inhibits expression of ENPEP by sponging miR-133b, thereby suppressing ESCC.

本研究旨在探究长链非编码RNA（long non-coding RNAs，lncRNAs）NCK1-AS1通过结合微RNA-133b（microRNA-133b，miR-133b）调控ENPEP，进而影响食管鳞状细胞癌（esophageal squamous cell carcinoma，ESCC）细胞增殖与侵袭活性的作用机制。研究基于食管鳞状细胞癌相关基因表达数据集GSE17351与GSE6188，筛选得到差异表达的lncRNAs、微小RNA及基因，并明确其靶向调控关系。通过功能实验验证了NCK1-AS1、miR-133b与ENPEP之间的靶向关联。本研究开展功能缺失与功能获得性实验，以检测NCK1-AS1、miR-133b及ENPEP对食管鳞状细胞癌细胞增殖、侵袭、迁移、凋亡能力以及体内（in vivo）肿瘤发生的影响。实验结果显示，食管鳞状细胞癌组织中NCK1-AS1与ENPEP表达升高，而miR-133b表达降低。敲低NCK1-AS1或过表达miR-133b，可抑制食管鳞状细胞癌细胞的恶性特性及体内肿瘤发生能力。NCK1-AS1通过竞争性结合miR-133b调控ENPEP的表达。过表达ENPEP可逆转敲低NCK1-AS1对食管鳞状细胞癌细胞功能的抑制作用。本研究证实，沉默NCK1-AS1可通过海绵吸附miR-133b抑制ENPEP的表达，从而抑制食管鳞状细胞癌的进展。