The Expression And Biological Function Of PADI4 In Esophageal Squamous Cell Carcinoma

Objective This study intends to validate the expression of PADI4 in esophageal cancer tissues and matched adjacent normal tissues and esophageal squamous cell carcinoma cell lines.The relationship between the expression level of PADI4 and the clinicopathological features of patients with esophageal squamous cell carcinoma was analyzed.The current study aims at revealing the functional mechanism of PADI4 in the development and progression of esophageal squamous cell carcinoma and its potential as a biomarker and therapeutic target for diagnosis and treatment of esophageal squamous cell carcinoma.Methods 1.Total RNA was extracted from pathological specimens of patients underwent esophageal cancer radical resection(including esophageal squamous cell carcinoma and its matched adjacent normal tissues)for high-throughput transcriptome sequencing;2.Differentially expressed coding genes were screening out using bioinformatic methods;3.Real-time quantitative polymerase chain reaction(RT-q PCR)was conducted to detect the expression of PADI4 in 73 cases of esophageal squamous cell carcinoma tissues and matched adjacent normal tissues.Combined with clinical pathological data,the correlation between the expression level of PADI4 and clinical pathological characteristics was analyzed;4.Real-time quantitative polymerase chain reaction(RT-q PCR)was used to detect the expression of PADI4 in esophageal squamous carcinoma cell lines;5.PADI4 was knocked-down by specific small interfering RNA in esophageal squamous carcinoma cell lines,and the effects of PADI4 on proliferation,colony formation,migration and invasion of esophageal squamous carcinoma cells were detected by MTS,colony formation and Transwell chamber experiments.Results 1.High-throughput sequencing results show that there are many differentially expressed genes in esophageal squamous cell carcinoma.Compared with adjacent normal tissues,PADI4 was significantly up-regulated in esophageal squamous cell carcinoma,and the fold change was greater than 5.5;2.Real-time quantitative PCR showed that the expression level of PADI4 in 56 cases(56/73,76.7%)of esophageal squamous cell carcinoma was significantly higher than that of the corresponding adjacent normal tissues(P<0.05);3.The expression level of PADI4 was closely related to tumor location(P=0.011),regardless of gender,lymph node metastasis,depth of invasion,and degree of tumor differentiation(P>0.05);4.Compared with adjacent normal tissues,PADI4 was upregulated in esophageal squamous carcinoma cell lines;5.The level of PADI4 in the esophageal squamous cell carcinoma cell lines was significantly lower than that of the negative control group(P<0.001)after using small interfering RNA in esophageal squamous cell carcinoma cell lines;6.MTS and plate colony formation experiments showed that,compared with negative control group,the proliferation and colony ability of cells was significantly inhibited(P<0.001)after knocking-down the expression level of PADI4 in esophageal squamous carcinoma cell lines;7.Transwell chamber experiments showed that,compared with negative control group,the migration and invasion ability of the cells were significantly inhibited(P < 0.001)after knocking-down the expression level of PADI4 in esophageal squamous carcinoma cell lines.Conclusion 1.There are a large number of differentially expressed coding genes in esophageal squamous cell carcinoma tissues;2.The expression level of PADI4 is significantly up-regulated in esophageal squamous cell carcinoma and esophageal squamous carcinoma cell lines,make it possible to be a biomarker for the diagnosis of esophageal squamous cell carcinoma;3.The expression level of PADI4 was closely related to the tumor location of patients with esophageal squamous cell carcinoma(P<0.05),and was not related to gender,lymph node metastasis,depth of invasion and tumor differentiation(P>0.05);4.The cell proliferation,cell colony,migration and invasion ability of esophageal squamous carcinoma cells were significantly inhibited after knocking-down the expression level of PADI4 in esophageal squamous cell carcinoma cell lines by specific small interfering RNA,which indicate that PADI4 may be playing an oncogene in the development of esophageal squamous cell carcinoma and a potential target for the treatment of esophageal squamous cell carcinoma.