The Role And Mechanism Of Th22 Cells And Their Secreting Cytokine IL-22 In Triple Negative Breast Cancer

Objective:Triple negative breast cancer(TNBC)refers to breast cancer with negative ER,PR and Her2,accounting for 15-20%of all types of breast cancer.In recent years,with the development of targeted drugs,the prognosis of breast cancer patients has been greatly improved.However,owing to the absence of any targeted therapy,TNBC which often occurs at an early age,typically have a worse outcome,lower overall survival and shorter relapse free survival.Searching for biological markers for prognosis and new therapeutic targets of TNBC is a hot and difficult topic.In recent years,more and more studies have found that TILs in tumor microenvironment play an important role in the occurrence and development of TNBC.Different TILs subgroups play distinct roles.Searching for specific subgroups and its secreted cytokines may find new biological markers related to the prognosis and therapeutic targets of TNBC.Th22 cell is a newly discovered CD4+ T lymphocyte subset,which secretes IL-22 at a high level,but does not secrete IFN-y,IL-4 and IL-17.The main effector cytokine of Th22 cells is IL-22 and its biological function is realized by IL-22.IL-22 plays an important role in many tumors.The key difference between IL-22 and other cytokines is that IL-22 originates from immune cells but acts on non-hematopoietic epithelial cells,which suggesting that IL-22 may be a key factor in the interaction between epithelial cells and immune cells.This study was designed to investigate the role and mechanism of Th22 cells and their secretory cytokine IL-22 in TNBC.Methods:The expression of Th22 cells and its secreting cytokine IL-22 in the tumor microenvironment of TNBC patients was detected by flow cytometry and ELISA.The relationship between the expression of IL-22 and clinicopathological characteristics and prognosis of TNBC patients was analyzed to determine whether IL-22 could be used as a biological marker for prognosis.MTT assay was used to detect the effect of IL-22 on TNBC cell proliferation.Wound healing assay and Transwell migration assay were used to clarify the effect of IL-22 on TNBC migration.Flow cytometry was used to detect the role of IL-22 in paclitaxel-induced apoptosis of TNBC cells and to study the relationship between IL-22 and paclitaxel resistance.Western Blot assay was used to detect the phosphorylation levels of JAK-STAT3,ERK,p38 and AKT,and to elucidate the mechanism of IL-22 in TNBC.Result:(1)Th22 cells in TNBC tissues were significantly higher than those in normal breast tissues(p<0.001).Serum IL-22 levels in TNBC patients were also significantly higher than those in patients with benign breast diseases.The level of IL-22 was correlated with TNM stage.The level of IL-22 in stage ? patients was significantly higher than that in stage ? and ? patients(p<0.001).According to the level of IL-22 in triple negative breast cancer patients,we divided them into two groups:high expression group(IL-22 level>320pg/ml)and low expression group(IL-22 level?320pg/ml).According to the analysis of clinicopathological characteristics,patients with high expression of IL-22 were more prone to lymph node metastasis and had higher histological grade.Long-term follow-up showed that the disease-free survival time of patients with high expression of IL-22 was significantly shorter than patients with low expression of IL-22(p<0.05).(2)MTT assay showed IL-22 promoted the proliferation of TNBC cells.With the increase of IL-22 concentration,the promotion effect was significantly enhanced(p<0.001).(3)Wound healing assay and Transwell migration assay showed that IL-22 promoted the migration of TNBC cells.With the increase of IL-22 concentration,the promotion effect was significantly enhanced(p<0.001).(4)Flow cytometry showed that IL-22 could inhibit the apoptosis of paclitaxel-induced TNBC cells.With the increase of IL-22 concentration,the inhibition of apoptosis was significantly enhanced(p<0.05).(5)Western Blot analysis showed that IL-22 could activate JAK-STAT3,ERK,p38 and AKT,and phosphorylation was more significant with the increase of IL-22 concentration.Conclusion:In conclusion,Th22 cells and their secreted cytokine IL-22 are associated with the occurrence and development of TNBC.IL-22 may promote the growth of TNBC cells by activating JAK-STAT3/MAPKs/AKT signaling pathway,and may be a predictor of therapeutic efficacy and prognosis in TNBC patients.