Expression and function of chemokine CXCR 4 in esophageal squamous cell carcinoma

LI Shaojun; GUO Nannan; FENG Lei; ZHANG Cheng; QU Li; TANG Jian

doi:10.3969/j.issn.2097-1753.2025.01.009

Abstract：Objective To investigate the expression and clinical significance of chemokine CXC subfamily receptor 4(CXCR4)in esophageal squamous cell carcinoma(ESCC)and its impact on biological characteristics of ESCC cell lines.Methods Bioinformatics methods were used to analyze the expression of CXCR4 in ESCC(82 cases)and normal tissues(1 456 cases)from the TCGA+GTEx dataset.Nine fresh ESCC tissues and their paired paracancerous tissues,110 paraffin-embedded ESCC specimens,and 35 paired paracancerous tissues were collected.The mRNA levels of CXCR4 in 9 ESCC tissues and their paired paracancerous tissues were analyzed by qRT-PCR.The expression of CXCR4 in 110 ESCC and 35 paired paracancerous tissues was detected by immunohistochemistry.These tissues were divided into the CXCR4 low-expression group(46 cases)and the CXCR4 high-expression group(64 cases).The differences in age,gender,TNM stage and lymph node metastasis between the two groups were studied.The proliferation,migration,and invasion abilities of cells with knocked down expressions of CXCR4 were detected using the cell counting kit-8(CCK-8 reagent),scratch assay,and Transwell assay.The effect of knocking down CXCR4 expression on epithelial-mesenchymal transition(EMT)was examined by Western blot(WB),immunofluorescence,and Transwell assay.Results The results of bioinformatics analysis showed that the expression of CXCR4 mRNA in ESCC tissues was higher than in normal esophageal tissues in the TCGA+GTEx dataset(t=9.524,P＜0.001).qRT-PCR analysis suggested that the mRNA level of CXCR4 in ESCC tissues was higher than in paracancerous tissues(t=9.967,P＜0.001).The CXCR4 protein expression level in ESCC tissues was higher than in paracancerous tissues(t=5.742,P=0.007).There were statistically significant differences in TNM stage,N stage,and survival time between the CXCR4 low-expression group(46 cases)and the CXCR4 high-expression group(χ2=15.325,13.628,both P＜0.001;χ2=5.673,P=0.021).The results of the CCK-8 assay indicated that the OD values of cells in the si-CXCR4 transfection group were lower than in the si-NC transfection group at 48 h and 72 h(P=0.019,0.013).Transwell assay showed that the numbers of migrating and invading cells in the si-CXCR4 transfection group were smaller than in the si-NC transfection group(t=5.790,4.075,P=0.005,0.008).After knocking down CXCR4,the fluorescence intensity of E-cadherin expression increased,the fluorescence intensity of Vimentin decreased,and the EMT process induced by stromal cell-derived factor-1(SDF-1)was blocked.The numbers of migrating and invading cells in the si-CXCR4 transfection combined with SDF-1 treatment group were smaller than in the si-NC transfection combined with SDF-1 treatment group(F=14.290,6.944,P=0.008,0.044).Conclusion Knocking down CXCR4 can inhibit the migration,invasion,and EMT process of ESCC cells.CXCR4 is highly expressed in ESCC tissues and is associated with poor prognosis,which can be used as a prognostic factor and a potential therapeutic target for ESCC.