| Objective:Osteosarcoma is one of the most common types of primary bone tumors.Chotherapeutic resistance and lung metastasis are important factors that affect the prognosis of patients during the occurrence and development of the disease.It is now the second leading cause of cancer-related death worldwide.The clinical manifestations are mostly bone,joint pain and local foot mass.The most typical pathological feature is that tumor cells can directly produce bone-like tissue.In addition to the traditional surgical treatment: amputation,limb-salvage surgery,current targeted therapy for the treatment of osteosarcoma also provides more accurate treatment mode,such as the epidermal growth factor receptor EGFR blockers,certain cells markers of monoclonal antibodies and so on,but now can be used for clinical molecular targets for the treatment of osteosarcoma of the very few,the heterogeneity of osteosarcoma itself determines the difficulty of the treatment and research.Bioinformatics mining technology demonstration experiment in molecular mechanisms can be based on the data of osteosarcoma of the genes and proteins in multi-dimensional comprehensive analysis,so this topic such analysis and validation method for tumor exist complex relationships,particularly for the high heterogeneity of osteosarcoma is a relatively comprehensive analysis results are obtained.Aimed at:1.The differentially expressed genes between osteosarcoma and normal tissue were screened by bioinformatics analysis method,and then module analysis was conducted to construct a high-risk characteristic model of the genes in the key modules,and further screening out the gene STC2 related to the patient's prognosis.2.The physical and chemical properties,localization patterns,interacting proteins and co-expressed genes of STC2 were predicted and analyzed.3.To verify the relationship between STC2 gene expression and clinicopathological characteristics,and to explore the potential of STC2 as a prognostic marker for osteosarcoma.Methods:1.Data mining of prognostic genes related to osteosarcoma and construction of gene expression characteristic model(1)Two osteosarcoma datasets,GSE12865 and GSE42352,were selected from Gene Expression Omnibus(GEO)database.After downloading the original data,the differentially expressed genes(DEGs)between osteosarcoma and normal tissue were analyzed.The differentially expressed genes were divided into four groups according to different expression levels,and the enriched cell components of the four groups were analyzed.(2)Modular analysis of differentially expressed genes was performed using Cytoscape,and Surv Express was used to construct expression models for genes in key modules,and genes related to prognosis in high-risk groups were screened out.2.Bioinformatics analysis of the role of STC2 gene in osteosarcoma(1)Prot Param was used to predict the physicochemical properties of STC2 protein,and TMHMM was used to analyze the transmembrane region and subcellular localization of STC2 gene.(2)Oncomine,Cell and other databases were used to analyze the basic expression of STC2 in osteosarcoma tissue and CELL levels.The physical and chemical properties,localization patterns,interacting proteins and co-expressed genes of STC2 were predicted and analyzed.It should be noted that there are few records on osteosarcoma in major databases at present,and we used indirect comparison to prove the expression of STC2 gene in osteosarcoma tissues.3.To verify the expression and clinical significance of STC2 in osteosarcoma(1)Osteosarcoma samples and clinicopathological data(43 cases)were collected from the Department of Pathology,The Second Hospital of Shanxi Medical University.All sections were stained by STC2 immunohistochemistry,and then the positive location and positive rate of STC2 were evaluated and analyzed.(2)Statistical analysis of the relationship between STC2 and clinicopathological characteristics of patients with osteosarcoma in the Second Hospital of Shanxi Medical University,and verification of the results of big data analysis of 305 patients with osteosarcoma in TCGA.It should be noted that osteosarcoma,as a major type of sarcoma,is essentially a malignant tumor originating from mesenchymal tissue,so we consider S as a reference in this comparison.(3)The effect of STC2 on proliferation of osteosarcoma cells was verified by cytology using the Encyclopedia of Cancer Cell Lines database.Results:1.Data mining of prognostic genes related to osteosarcoma and construction of gene expression characteristic model(1)The three and four groups of genes with higher differential expression were mainly concentrated in the cell membrane and outside the cell(2)The module score of module 2 was higher and composed of 22 genes enriched in extracellular matrix framework.(3)The 22 genes in module 2 can be divided into two groups according to the high and low risk,and the high risk group is significantly associated with poor prognosis of patients.(4)The expression levels of MMP9,EVA1 A,SPP1,and STC2 were significantly correlated with poor prognosis in high-risk group(5)Univariate survival analysis showed that only SPP1 was significantly associated with poor prognosis.2.Expression and role of STC2 gene in osteosarcoma(1)STC2 has strong stability and regulates cellular calcium/phosphate homeostasis.Overexpression of STC2 will lead to decreased growth of bone and skeletal muscle.(2)There is no transmembrane region of STC2,and the human STC2 protein is mainly distributed in the endoplasmic reticulum and extracellular.(3)STC2 was overexpressed in both osteosarcoma tissues and osteosarcoma cell lines.Among the different subtypes of osteosarcoma,STC2 is highly expressed in osteoblast and chondroblast osteosarcoma.(4)Data analysis of both GEPIA and TCGA showed that STC2 was significantly associated with poor survival outcomes.(5)Among the top 10 proteins most closely related to STC2 protein,5 of them had biological functions related to osteogenesis.(1)Forty-three cases of osteosarcoma from the Second Affiliated Hospital of Shanxi Medical University were collected for STC2 immunohistochemistry.The results showed that STC2 protein was mainly localized in the nucleus.(2)Analysis of the relationship between STC2 and the clinicopathological characteristics of patients with osteosarcoma showed that the immunohistochemical staining intensity of STC2 was related to the site before and after chemotherapy,and the difference was statistically significant.(3)The effect of STC2 on the proliferation of osteosarcoma cells was verified by cytology.The results showed that the proliferation of osteosarcoma cell lines with overexpression of STC2 gene was significantly enhanced compared with that of osteosarcoma cell lines with knockout.Conclusion:1.Data mining of prognostic genes related to osteosarcoma and construction of gene expression characteristic model(1)In the osteosarcoma dataset GSE12865 and GSE42352,the three and four genes with higher differential expression were mostly enriched extracellular,and module 2 with higher module score was also enriched here,suggesting that the highly expressed genes that mainly regulate the occurrence and development of osteosarcoma may play their biological functions in the extracellular or cellular matrix framework.(2)Through the establishment of expression characteristic model and univariate multivariate survival analysis,SPP1 was significantly associated with poor prognosis in patients with osteosarcoma2.Expression and role of STC2 gene in osteosarcoma(1)STC2 gene can regulate calcium and phosphorus homeostasis,and STC2 protein is highly expressed in osteoblastic and chondroblastic osteosarcoma,suggesting that STC2 protein is closely related to the occurrence and development of osteosarcoma as a secretory protein.(2)STC2 is significantly associated with poor prognosis in patients with osteosarcoma.3.To verify the expression and clinical significance of STC2 in osteosarcoma(1)In the 43 cases of osteosarcoma tissue,STC2 protein was located in the nucleus in 41 cases,and the negative and positive STC2 staining was correlated with the location before and after chemotherapy,and the difference was statistically significant.(2)The overexpression of STC2 significantly enhanced the proliferation of osteosarcoma cell lines. |
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