Clinical Significance And Biological Function Of BCLAF1 In Esophageal Squamous Cell Carcinoma

Background: In China,the incidence of esophageal cancer(ESCA)is very high,of which the number of new cases of ESCA each year accounts for more than half of the world.Esophageal squamous cell carcinoma(ESCC)is the main pathological type of ESCA patients in our country,accounting for more than 95%.Due to the lack of obvious symptoms,early ESCA is hidden and difficult to diagnose.At present,patients with advanced ESCA are mainly treated by surgery,supplemented by radiotherapy,chemotherapy,and immunotherapy,but the curative effect is limited and the prognosis is poor.Detailed research on the key molecules in the occurrence and progression of ESCC will help to improve the understanding of the pathogenesis of ESCC,which will provide theoretical and experimental basis for the development of precise diagnosis and treatment targets for ESCC.We have found a series of abnormally expressed proteins including BCLAF1 in the TMT-labeled quantitative proteomics detection of ESCC.Objectives: 1.Detect the expression of BCALF1 in ESCC,in addition,analyze the correlation between BCLAF1 and tumor staging,survival prognosis and other feature.2.Explore the effects of BCLAF1 on the proliferation,cell cycle,apoptosis,invasion and migration of ESCC cells via experiment in vitro and in vivo.Methods: 1.The expression of BCLAF1 in pan-cancer species was investigated via GEPIA database.2.ESCC and paired adjacent non-cancerous tissue section were analyzed by IHC staining,scored according to the expression intensity of BCLAF1 and the proportion of staining area.In addition,we conduct clinical correlation analysis combined with tumor staging,survival prognosis and other patient information.3.The CRISPR/CAS9 and SAM dual-vector lentiviral system were used to construct stable transfected ESCC cell lines,and the protein expression level was verified by Western Blot.4.CCK-8 assay and colony formation assay were used to detect the proliferation in vitro.Cell scratch test and Transwell chamber experiment were used to detect the migration and invasion of ESCC cells in vitro.PI staining and Annexin V/PI double staining combined with flow cytometry were used to analyze cell cycle and apoptosis.5.Nude mice subcutaneous xenograft tumor model and lung metastasis model were used to research the proliferation and metastatic of ESCC cell in vivo.Results: 1.GEPIA analysis suggests that BCLAF1 is up-regulated in a variety of malignent tumors including ESCA.2.IHC staining showed that the expression of BCLAF1 protein in ESCC was significantly higher than that in adjacent tissues.Moreover,the higher BCLAF1 expression level is correlated with the more advanced tumor staging.The survival time of the high expression group is shorter than that of the low expression group.3.CCK-8 assay,colony formation assay,cell scratch test and Transwell chamber experiment suggest that BCLAF1 can promote the proliferation,invasion and migration of ESCC cells in vitro.Flow cytometry assays showed that BCLAF1 can promote cell cycle progression,but the effect on early apoptosis did not show statistical difference.4.Experiments in nude mice confirm that BCLAF1 can promote the proliferation and lung metastasis of ESCC cells in vivo.Conclusions: 1.BCLAF1 is up-regulated in ESCC,whose expression is significantly correlated with advanced tumor staging and poor survival prognosis.2.In vitro and in vivo study,BCLAF1 facilitate the proliferation,invasion and migration of ESCC cells,promotes its malignant biological behavior,and can regulate the cell cycle.