| Hepatoblastoma(HB)is an embryonic tumor derived from hepatocytes and is one of the most common malignant tumors in children.There are two main pathological types about HB:epithelial(about 80%)and mixed(epithelial-mesenchymal).resection is the primary means of curative treatment in children with HB,but only about one-third of the patients with initial diagnosis can achieve radical resection.The factors affecting the prognosis of patients with HB include:the expression level of alpha fetoprotin(AFP),radical surgical resection,tumor stage,tumor metastasis and histology.In addition,some researches have found mutations in sub-types of HB,but these mutations are rarely used in clinical treatment.Therefore,it is necessary to find new molecular mutations in HB and to achieve homologous treatment for HB patients.Periostin(POSTN)is prominently expressed in most fetal tissues and plays an important role in embryonic development.In recent years,POSTN has been found to be abnormally expressed in many malignant tumors,such as lung cancer,breast cancer,colorectal cancer prostate cancer and so on.It is reported to be associated with the malignancy and invasiveness of tumors.Besides,it is also evidenced that POSTN expressed in adenovirus-infected human renal epithelial cells(293T)can induce mesenchymal transition(EMT)in certain epithelial cells.EMT usually related to the invasive characteristics,metastatic potential and drug resistance of cancer cells.Therefore,the relationship between POSTN and tumorigenesis and development is one of great significance for the diagnosis and treatment of tumors.However,the impact of POSTN expression on the progression and prognosis of HB is unclear.Therefore,the purpose of this study was to demonstrate whether POSTN can induce HB cells to develop EMT and further explore the transformation mechanism.Methods:1.Detection of POSTN expression in HB tissuesThe expression levels of POSTN in 47 cases of HB patients were confirmed by Western blot,immunochenical methods.2.To verify the relationship between POSTN and pathological characteristics and survival prognosis of HB patientsSPSS22.0 statistical software was used to analyze the correlation between the expression level of POSTN and its clinicopathological features and survival prognosis in 47 cases of patients with HB.3.Vitro experiments:the effect of POSTN on the biological behavior of HB cells(1)Construct HB cell lines with stable downexpression or overexprission POSTN by lentiviral infection.(2)The effects of POSTN on the adhesion,migration and proliferation of HB cell lines were verified by cell-matrix adhesion assay,cell migration assay,cell cycle assay and apoptosis assay.(3)The effect of POSTN downexpression and overexpression on factors related to epithelial-mesenchymal transition in HB cell lines were detected by Western blot.The molecular mechanism of POSTN promoting HB cell migration and invasion was further explored.4.Vivo experiments HB cell lines were injected subcutaneously into mice to detect the effect of POSTN on tumor proliferation.5.Clinical samples testThe results of the mechanism study of POSTN promoting HB progression wereexamined in clinical samples by immunohistochemistry,immunofluorescence,and Western blotting.Results:1.POSTN was highly expressed in HB tissues,including 20 cases of patients(42.6%)with strong positive expression,and its expression level was positively correlated with tumor stage.2.Statistical analysis showed that lymph node metastasis(X~2=47.245,P<0.001),vascular invasion(X~2=12.899,P<0.001)and POSTN expression level(X~2=6.715,P=0.01)were the significant risk factors of the prognosis of HB patients.The expression of POSTN was significantly correlated with the expression of Vimentin(X~2=5.232,P=0.045)in HB tissues.There was no significant correlation between the expression of POSTN and the expression of E-cadherin(P>0.05).3.After the stable overexpression of POSTN in HB cells,the cell adhesion and migration ability increased;while the expression levels of Vimentin,Snail and P-Erk were up-regulated,and the expression levels of E-cadherin and OVOL2 were down-regulated.When the Erk1/2 specific inhibitor PD98059 interfered with the POSTN overexpression cells,the expression level of E-cadherin was up-regulated,and the Vimentin expression level was down-regulated.4.Compared with the control cell line,the tumorigenic ability was significantly increased after injection of the POSTN overexpression cell line.5.Vimentin and p-Erk were highly expressed in clinical samples of HB patients,and were associated with poor prognosis.E-cadherin was low expression and was not associated with prognosis.Conclusion:1.POSTN was highly expression in HB patients and is positively correlated with tumor stage and negatively correlated patients`prognosis,suggesting that POSTN was a cancer-promoting factor of HB.2.Cell biology experiments confirmed that POSTN promoted migration and invasion of HB cells,and in vivo experiments demonstrated that promoted HB proliferation.3.POSTN regulated epithelial-mesenchymal transition through the Erk signaling pathway,thereby promoting cell migration and invasion. |
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