| Objective: Epithelial ovarian cancer（EOC）has the highest mortality rate among gynecological malignancies.The major treatment plan for patients is the surgery combined with cisplatin-based chemotherapy,which accompanied by treatment failure.Clinical trials for the treatment of ovarian cancer have focused on immunotherapy approaches,most importantly immune checkpoint inhibitors such as programmed cell death 1（PD-1）inhibitors and IDO inhibitors.However,the response rate of IDO inhibitor combined with PD-1 inhibitor immunotherapy in EOC patients remains low.Other literatures have confirmed that the high expression of IL4I1 in melanoma can decompose tryptophan and activate AHR to produce immunosuppressive effect,which is similar to the decomposition of tryptophan by IDO.It is speculated that the poor effect of immune combination and chemotherapy in ovarian cancer may be due to the presence of IL4I1.Our previous study found that there was differential expression of My D88 in ovarian cancer cell lines.Paclitaxel and LPS could induce the formation of TLR4-MD2 dimer,which activated the downstream TLR4/My D88 signaling pathway and up-regulated the expressions of IL-6,PD-L1,IDO1 and AHR,resulting in immunosuppression and paclitaxel resistance of ovarian cancer cells.The purpose of this study was to determine whether activation of the TLR4-MD2/My D88/PI3K/Akt/NF-κB signaling pathway can affect the expression of IL4I1 and lead to immunosuppression of ovarian cancer.we hope IL4I1 therapy will become a promising treatment for ovarian cancer.In addition,a gene co-expression network was constructed based on bioinformatics to identify the pivotal genes involved in ovarian cancer and establish a prognostic prediction model.Methods:（1）The mRNA expressions of IL4I1,Ah R and My D88 in OVCAR 3 and A2780 cells were detected by RT-qPCR at 2 hours /6 hours after LPS treatment.Western blot was used to detect the protein expressions of IL4I1,Ah R and My D88 in OVCAR-3and A2780 cells treated with LPS at appropriate concentration for 6h/12h/24 h.（2）The dataset GSE26712 was downloaded from GEO,and the co-expression network was constructed by weighted gene co-expression network analysis（WGCNA）.The co-expression network was intersected with the differential gene results,and visualized with gene ontology（GO）and Kyoto Encyclopedia of Genes and Genomes（KEGG）enrichment analysis.The prognostic related genes of overlapping genes in GSE26712 data（Train group）were obtained,and the model was constructed and tested in TCGA sample data（Test group）.The differences of immune cells and immune-related functions in high and low risk groups in TCGA data were analyzed.Results:（1）mRNA levels: The mRNA expression of IL4I1,AHR and My D88 were low in human ovarian cancer A2780 cells,and the mRNA expressions of IL4I1,AHR and My D88 in human ovarian cancer OVCAR-3 cells were significantly higher than those in human ovarian cancer A2780 cells after 2h and 6h in LPS medium（P<0.05）.The mRNA expression levels of IL4I1,AHR and My D88 were the highest after 2h treatment（P<0.05）.Protein levels: The protein expression levels of AHR and My D88 in OVCAR-3 cells were higher than those in A2780 cells（P<0.05）.When cells were cultured in LPScontaining medium,the protein expression of AHR and My D88 genes in OVCAR-3 cells was higher than that in A2780,with statistical difference（P<0.05）.（2）Prognosis model =BNC1 expression ×0.06+CERK expression ×0.24+FOXO1expression ×0.14+GALNT6 expression ×（-0.22）+MRPL2 expression ×（-0.2）+PRSS2expression ×（-0.07）.Patients with low prognostic index had better overall survival than those with high prognostic index（OS）,which was consistent with the TCGA dataset.Conclusions: The mRNA expressions of IL4I1,AHR and My D88 in OVCAR 3 cells were significantly higher than those in A2780 cells,and LPS could significantly increase the expression of IL4I1,AHR and My D88 in OVCAR 3 cells.The protein expression of AHR and My D88 in OVCAR 3 cells was significantly higher than that in A2780 cells,and LPS significantly increased the expression of AHR and My D88 in OVCAR 3 cells.These results indicate that activation of TLR4/My D88 signaling pathway can affect IL4I1 and improve immunosuppressive status and paclitaxel resistance of ovarian cancer.The gene prognostic model of ovarian cancer is a promising biomarker that can be used to distinguish the prognostic,molecular and immune characteristics of ovarian cancer. |
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