Systematic Cancer-Testis Long Non-Coding Rna Analysis Identifies LEF1-AS1, Promotes Esophageal Squamous Cell Carcinoma Progression Via Mediating PDCD5/P53 Axis

Background: Cancer-testis genes (CTGs) have been reported to regulate various cancer development. CTGs are considered as ideal targets for tumor immunotherapy. However, the relationship between CTGs and long non-coding RNA (lncRNA), especially the emerging functional role and clinical significance of which in esophageal squamous cell carcinoma (ESCC) remains to be further clarified. Methods: A systematic strategy was built for related cancer-testis long non-coding RNAs (CT-lncRNAs) screening. Several public-available databases were used to analyze lncRNA expression and prognosis. Small interfering RNAs (siRNAs) or overexpressed plasmids were transfected into ESCC cells to knockdown or overexpress LEF1-AS1 or PDCD5 levels. The nuclei and cytoplasm of ECA109 cells were analyzed by RISH assay. RNA sequencing was used to screen the significantly changed genes and pathways by LEF1-AS1 knockdown. RNA pulldown and mass spectrometry were designed to detect proteins bound to LEF1-AS1. CCK-8, colony formation, flow cytometry and transwell assays were performed to assess cell function. Furthermore, the tumor transplantation model in mice was used to investigate the role of LEF1-AS1 on ESCC progression. Findings: 447 genes were recognized as CT-lncRNAs, in particular, LEF1-AS1 was aberrantly upregulated in ESCC tissues and significantly associated with poor prognosis. LEF1-AS1 promoted the progression of ESCC through regulating cancer-related genes in vitro and in vivo. Mechanistically, PDCD5 was directly bound to LEF1-AS1, and modulated p53-mediated pro-apoptotic signaling in ESCC. Rescue assay confirmed that LEF1-AS1 regulated the expression of p53 through binding with PDCD5, thus promoting the progression of ESCC. Interpretation: LEF-AS1/PDCD5/p53 axis plays an important role in the ESCC tumorigenesis, which provides an ideal target for the diagnosis and therapy of ESCC. Funding: This work was supported by Jiangsu Top Expert Program in Six Professions (No. WSW-003) and Jiangsu Medical Young Talent Project (No. QNRC2016566). Declaration of Interest: None to declare. Ethical Approval: The study has been approved by the ethics committee of the First Affiliated Hospital of Nanjing Medical University.