Abstract
BACKGROUND: Lymph node metastasis is the main type of metastasis in esophageal squamous cell carcinoma (ESCC), especially when the primary tumor invasion depth reaches above the adventitia layer (T3 stage), the incidence of lymph node metastasis increases sharply. Abnormal expression of long non-coding RNAs (lncRNAs) has been confirmed in ESCC, but there are still many unknown connections between lncRNAs and lymph node metastasis. METHODS: We used transcriptome sequencing (RNA-seq) to analyze 10 pairs of ESCC tissues with primary tumor stage T3 and their paired normal epithelium. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to further verify the sequencing results, and survival curve analysis, logistic regression analysis, and receiver operating characteristic (ROC) curve analysis were used to investigate its clinical application value. We investigated the growth and metastasis effects of lncRNA GAS6-AS1 on ESCC cell lines TE-1 and KYSE410 in vitro and in vivo. Other functional experiments included cell apoptosis and cell cycle experiments. RESULTS: Based on our RNA-seq data, lncRNA GAS6-AS1 is highly expressed in ESCC tissues, especially in cancer tissues with lymph node metastasis. The qRT-PCR experiment analysis showed that high expression of GAS6-AS1 was related to poor tumor differentiation and tumor stage. Logistic regression analysis showed that it was an independent risk factor for lymph node metastasis, and ROC analysis validated that it could predict lymph node metastasis. Further survival analysis suggested that high expression of GAS6-AS1 was associated with patients' poor prognosis. In vitro experiments, knocking down GAS6-AS1 inhibited the growth and metastasis of ESCC cells and inhibited tumor growth in vivo. In addition, knocking down GAS6-AS1 can inhibit cell cycle and promote cell apoptosis. CONCLUSIONS: Our results revealed that lncRNA GAS6-AS1 obtained from RNA-seq can be used as an independent risk factor for ESCC lymph node metastasis and an effective biomarker to predict, and that it was related to the growth and metastasis of ESCC. It may represent a new biomarker to aid in the assessment of the lymph node metastasis of ESCC.