| ObjectiveEsophageal cancer is one of the leading causes of cancer-related deaths worldwide,there are approximately half of all cases of esophageal cancer occur in China.Although the diagnosis and treatment of esophageal cancer has made great progress in early detection,accurate diagnosis and combination therapy,the overall five-year survival rate of esophageal cancer is still very low.Tumor is a gradual chronic process in which the interaction of tumor cells with the surrounding environment forms a complex and variable tumor microenvironment,which determines the progression and outcome of the tumor.The functional status of immune effector cells in the tumor microenvironment is one of the key mechanisms affecting tumor outcome.Immune cells are important cells for the body to play an immune surveillance function.The functional defects of immune cells are one of the important mechanisms of tumor immune escape.T cell immunoglobulin mucin 3(Tim-3)is a new immune checkpoint,and the expression of immune cells on the surface induces the immune cells to decrease the abilities of recognize and kill tumor cells.However,the expression of Tim-3 on NK cells in the tumor microenvironment of esophageal cancer patients is not clear.Natural killer(NK)cells are important effector cells of the innate immune system and participate in the body's first line of defense against tumors.The main function of NK cells is to directly kill tumor cells and secrete cytokines such as IFN-?.Targeting NK cells may provide new therapeutic strategies for tumors.This subject mainly studies the characteristics and clinical significance of NK cell cell function defects in esophageal cancer tumor microenvironment.Furthermore,to improve the prognosis of patients,and find a potential therapeutic target for esophageal cancer immunotherapy.MethodsWe prospectively collected peripheral blood and tumor samples from 53 patients with esophageal cancer.Peripheral and tumor-infiltrating NK cells were analyzed for Tim-3,Annexin V,CD69,CD107a and IFN-?expression by flow cytometry.Immunofluorescence was used to detect the relationship between Tim-3 and NK expression in esophageal cancer tissues and adjacent tissues.The NK cells of Tim-3~+and Tim-3~-in the microenvironment of esophageal cancer tumors were sorted by flow cytometry.RNA was amplified by micro-amplification,and finally quantitative real-time PCR was used to test relative mRNA expression of IFN-?,granzyme B,perforin and NKG2D in sorted Tim-3~+NK cells and Tim-3~-NK cells,respectively.NK cells isolated from healthy donors were treated with recombinant TNF-?to induce Tim-3 expression.NK cells were induced by recombinant TNF-?to detect the expression of Tim-3 by immunofluorescence,quantitative real-time PCR and flow cytometry.Tim-3 and TNF-?Mrna levels in tumor tissues were measured in both humans and mice.Download of TCGA database,analysis of Tim-3 and TNF-?mRNA expression levels and their correlation;finally,associations between NK cell frequencies with pathological parameters were investigated.ResultsWe observed up-regulation of Tim-3 expression on NK cells from esophageal cancer patients,especially at the tumor site.Furthermore,tumor-infiltrating NK cells with high Tim-3 expression exhibited a phenotype with enhanced dysfunction.In vitro,Tim-3 expression on NK cells isolated from blood of healthy donors can be induced by recombinant TNF-?via NF-?b pathway.In both animal models and patients,the Tim-3 level was positively correlated with TNF-?expression in esophageal cancer tissues.Finally,higher Tim-3 level on tumor-infiltrating NK cells is correlated with big tumor size,nodal status and poor stage in patients with esophageal cancer.ConclusionTaken together,Tim-3 may play a crucial role to induce NK cell dysfunction in tumor microenvironment and could serve as a potential biomarker for prognosis of esophageal cancer. |
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