Cancer-testis non-coding RNA LEF1-AS1 regulates the nuclear translocation of PDCD5 and suppresses its interaction with p53 signaling: a novel target for immunotherapy in esophageal squamous cell carcinoma.

Despite the improvement of current classical treatment, the prognosis of esophageal squamous cell carcinoma (ESCC) remains poor. Immunotherapy, as a new treatment method, has revolutionized the therapy of various cancer types and created more attractive for ESCC. Cancer-testis genes (CTGs), because of its characteristic expression and immunomodulation property, are considered as the ideal targets for tumor immunotherapy. However, the ESCC-specific CTGs, especially long non-coding RNA (lncRNA), has not been elucidated. In the present study, a systematic strategy was adopted to screen ESCC-specific cancer-testis lncRNA (CT-lncRNA). Collectively, 447 genes were recognized as ESCC-specific CT-lncRNAs, in particularly LEF1-AS1 showed the most aberrantly expression and clinically associated with poor outcome. Functional assays revealed that H3K27 acetylation in LEF1-AS1 promoter might give rise to the activation of LEF1-AS1 during ESCC tumorigenesis. The activated LEF1-AS1 was predominantly localized in the cytoplasm implicated in regulation of apoptosis and proliferation capacities of ESCC cells in vitro and in vivo. Further mechanistic studies unveiled that LEF1-AS1 participated in ESCC by interacting with RNA binding protein PDCD5 through weakened its nuclear translocation binding to TP53, leading to p53 degradation and disruption the transcription of downstream genes. Taken together, our findings suggest that LEF1-AS1 acts as a CT-lncRNA and might be an ideal immunotherapeutic target for clinical intervention for ESCC.