SBEM Protein In Breast Cancer Cells With Different Expression Of Antigen Epitope Screening And Identification

Objective: Distant metastasis is the main cause of death in breast cancer patients.It is a necessary step for the proliferation of tumor cells to be mechanically captured andadhered with endothelial cells. These tumor cells are defined as micrometastasis that arehard to be detected by conventional examination methods. Earlier detection andintervention of micrometastasis are very important to improve patients’ outcomes. Smallbreast epithelial mucin (SBEM) specifically expresses in the breast tissues and is likelyto become a molecular biomarker for micrometastasis detection. Researching on thefunction and mechanism of SBEM protein may be helpful to detect and inhibit themicrometastasis of breast cancer cells. Screening out protective antigen epitope ofSBEM may provide ideal intervention targets for breast cancer immunotherapy.Methods:1, Using the immunocytochemical method to check the expression ofSBEM protein in three group cells of MCF-7, MDA-MB-231and SK-BR-3.2, Usingthe flow cytometry to detect the expression level of SBEM protein in MCF-7,MDA-MB-231and SK-BR-3group cells.3, Using semi quantitative PCR to analysisthe expression level of SBEM mRNA in MCF-7, MDA-MB-231and SK-BR-3groupcells.4, Using multiple parameters and the method with2kinds of epitope predictiondatabase (SYFPEITHI and ProPred-I) and tools to comprehensive analysis, and predictSBEM epitope of corresponding antigen peptide synthesis.Results:1, The immunocytochemical results show that SBEM protein was highexpression in MDA-MB-231cell membranes, and the expression level was higher thanthat of MCF-7cells and SKBR-3cells.2, The flow cytometry results show that theSBEM protein was in MDA-MB-231cells with high expression, and the expressionlevel is higher than that of MCF-7and SK-BR-3cells.3, The semi quantitative PCR detection results show that SBEM gene was high expression in MDA-MB-231cells andthe expression level is higher than that of MCF-7and SK-BR-3cells.4, Usingbioinformatics methods to design a new candidate antigen peptide of SBEM antigen, wegot only one nine peptide as tumor associated antigen SBEM by SYFPEITHI andProPred-I preliminary forecast and combination the analysis of MHCPRED2.0andNETCHOP3.0tools.Conclusion:1, SBEM protein and gene showed high expression in MDA-MB-231cells, and thus were significantly higher than the other two breast cancer cell lines. Itshowed that SBEM protein and mRNA had a different expression level in differentpathological types of breast cancer cells. Pathological type was worse; its expressionlevel was higher. Further applying the immunocytochemical staining method to checkits expression site on the breast cancer cell lines, the results show that SBEM proteinsare mainly expressed in the cell membrane. Tumor associated antigen SBEM as amembrane protein had a high expression in higher malignant degree of breast cancer,thus provides an important theoretical and experimental foundation for the candidateHLA-A*0201restrictive epitope.2, We screened a protective HLA-A*0201restrictedCTL candidate epitopes, LLGVSIFLV（9-17）and VLLGVSIFL（8-16）are the most affinitynine peptide, thus provide the ideal intervention target for the individual treatment ofbreast cancer metastasis. Using bioinformatics methods to predict epitopes, not onlycontributes to immunological technology development, but also contribute to the genevaccine and antibody drug research and development, thus provide new targets and newideas for biological immune therapeutic for the disease.