A Preliminary Study On The Relationship Between FKBP51 Expression And Macrophage Polarization In Gastric Cancer

Background and Objective:FKBP51?FK506 binding protein 51?is a member of the immunophilin family and is a receptor for intracellular immunosuppressant FK506 and rapamycin.When combined with them,it could exert immunosuppressive effects.Several studies have found that FKBP51 abnormally expressed in various tumor tissues such as colon cancer,pancreatic cancer,breast cancer,and melanoma,and it could affect the growth of tumor cells and their sensitivity to chemotherapy drugs.However,there are no reports about the expression of FKBP51 in gastric cancer.Studies have been reported that glucocorticoid?GC?binds to glucocorticoid receptor?GR?and induces the expression of FKBP51,while high expression of FKBP51 decreases the sensitivity of GR to glucocorticoid and reduces the efficiency of GR into the nucleus,so FKBP51 is the key molecule of giucocorticoid signal path.The glucocorticoid could induce macrophage phenotype from M1 to M2,inhibite the function of lymphocytes,thereby promoting tumor immune escape.We speculate that GR-FKBP51 may be the key path of the glucocorticoids to promote the macromolecular M2 polarization of gastric cancer.So we designed the experiment to observe the relationship between FKBP51 and macrophage polarization in gastric tumor tissues,and to initially investigate whether GR-FKBP51 is involved in the process of macrophage polarization promoted by glucocorticoids.Methods:1.We select 50 cases of patients received gastric cancer surgery in the first affiliated hospital of NanChang university from August 2014 to October 2014,then collected gastric cancer tissue,normal tissue and clinical data.The level of FKBP51,GR,CD68,CD163 and CD80 protein expression and differences of gastric cancer tissues and adjacent normal tissue were detected by the immunohistochemical analysis.FKBP51 protein expression intensity correlations with GR,CD68,CD163and CD80 protein level were further analyzed,respectively.Objective to analyze the relationship between FKBP51 expression and the clinical characteristics.2.The human THP-1 mononuclear cells were inoculated in 6-well plates at1×10⁶/ml density during logarithmic growth phase.Then PMA induced it to differentiate into macrophages.Real-time fluorescence quantitative polymerase chanin reaction?PCR?was respectively employed to detecte the expression of CD68in order to determine the optimal concentration and time of PMA.3.The macrophages derived from THP-1 monocytes were divided into four groups:control group,GC group,R group and GC+R group,randomly.In these groups,the macrophages were stimulated by dexamethasone(10^-6mol/L)and Ru486(10^-5mol/L)for 24h.Western blotting was respectively employed to examine the protein of FKBP51,GR and hsp90.The mRNA levels of FKBP51,GR,hsp90,IL-10,IL-12p35,TNF-?,TGF-?,CD163 and CCR7 were detected by real-time fluorescence quantitative polymerase chanin reaction?PCR?.Results:1.The positive expression intensity of FKBP51 in tumor tissue was significantly higher than tissue adjacent to carcinoma?P<0.05?,and there was no signficiant differences in the positive expression rate?P>0.05?.Of the patients with lymph node metastasis and in TNM staging III-IV,FKBP51 expression intensity in gastric cancer tissues were significantly stronger than of patients without lymph node metastasis and in TNM staging I-II?P<0.05?.2.The positive expression intensity of GR in tumors tissue was significantly lower than tissue adjacent to carcinoma?P<0.05?,and there was no signficiant differences in the positive expression rate?P>0.05?.Meanwhile there was no significant difference in the expression intensity of GR in lymphocyte in gastric cancer tissues between each group of different clinical and pathological features?P>0.05?.3.The positive expression rate and expression intensity of CD68 in tumor tissue were significantly higher than tissue adjacent to carcinoma?P<0.01?.4.The positive expression rate and expression intensity of CD163 in tumor tissue were significantly higher than tissue adjacent to carcinoma?P<0.05?.5.The positive expression rate and expression intensity of CD80 in tumor tissue were significantly lower than tissue adjacent to carcinoma?P<0.01?.6.The positive expression rate and intensity of FKBP51 protein in tumor have positive correlation with CD68 and CD163 protein,and the expression of GR showed a negative correlation with FKBP51 expression intensity.7.Compared with the control group,the FKBP51 protein expression and IL-10,TGF-?,CD163 mRNA expression levels in GC group were significantly increased,and glucocorticoid receptor antagonists could inhibit the indicators from the mRNA and protein levels?P<0.05?.Besides,the GR protein expression and IL-12p35,TNF-?,CCR7 mRNA expression levels in GC group were significanty decreased,and glucocorticoid receptor antagonists could promote the indicators?P<0.05?.However,there was no significant difference in hsp90 protein expression in GC group?P>0.05?,while hsp90 mRNA expression levels was down-regulated?P<0.05?.Conclusions:1.TAMs infiltrated in gastric cancer tissues are polarized into M2 phenotype,and it could be related to FKBP51.2.GC could induce macrophage phenotype from M1 to M2,promote the expression of FKBP51.GR antagonists could increase the expression of GR,decrease the expression of FKBP51,and swith the macrophages toward M1-like phenotype.3.Glucocorticoids may promote macrophage M2 polarization through the GR/Hsp90/FKBP51 complex and promote immune escape of tumor cells.