Mechanisms Of PEG10 Promoted Pancreatic Cancer Progression And The Diagnostic Value Of PEG10

Background:Pancreatic cancer one of thehighly aggressive malignancies in digestive system.The data published in China and all over the world suggested that the morbidity and mortality of pancreatic cancer increased yearly.Due to the significant tolerance to traditional chemotherapy drugs and the lack of targeted drugs,the only effective treatment for this cancer is radical resection at present.However,most patients are diagnosed with terminal stage when they visit the doctor,only twenty percentage of cancer patients have opportunity to receive radical surgery.Therefore,the exploration of novel diagnostic methods and therapeutic strategies for pancreatic cancer are imminent.PEG10 is an important member of imprinted gene families which plays a key role in the regulation of several cellular functions,including cell proliferation,cell apoptosis,and cell cycle.Similar to other paternal expressed imprinted genes,the abnormal expression of PEG10 is involved in the malignant process of some tumors.And the mRNA sequencing data in large sample pancreatic cancer showed that PEG 10 is generally expressed in pancreatic cancer.This results suggested that PEG 10 may contribute to the progression of pancreatic cancer.The role of PEG 10 in such cancer is needed to be investigated.Objective:1?To investigate the expression of PEG 10 protein on pancreatic cancer samples,and further to analyze the association between PEG10 expression and chinicopathological factors of pancreatic cancer,as well as the prognosis.2?To study the expression of PEG10 in pancreatic cancer cell lines,and to investigate the effects of PEG10 on cancer cell proliferation,invasion,and migration,as well as the potential regulatory mechanisms.3?To investigate the upstream regulatory mechanisms of PEG 10,and further to analyze the correlation between PEG 10 expression and upstream regulatory factors expression in samples.4?To determine the concentration of PEG10 in the plasma from pancreatic cancer patients,and further to evaluate the diagnostic value of PEG 10.Methods:1?Immunohistochemistry staining was applied to investigate the expression of PEG10 in pancreatic cancer samples;chi-square analysis and correlation analysis were both used to analyze the association between PEG 10 expression and?chinicopathological factors;Kaplan-Meier model and COX logistic regression model were applied to assess the influence of PEG 10 on the poor prognosis of pancreatic cancer patients.2?Western Blot and real-time fluorescent quantitative PCR were applied to detect the expression of PEG 10 in pancreatic cancer cell lines;small interfering RNA and overexpression plasmid vector were respectively used to construct PEG 10-.interference and overexpression cancer cell lines;CCK-8 assay,clone formation assay,EDU assay,and subcutaneous xenotrans planted tumor model were allied to evaluate the role of PEG10 on cell proliferation;Transwell assay and in situ xenotrans planted tumor model were used to assess the function of PEG 10 on cell migration and invasion.3?The mechanisms of PEG10 promoted cell proliferation were investigated by the apoptosis detection and cell cycle detection in flow cytometry,and various Western Blot assays;The mechanisms of PEG 10 induced cell migration and invasion were studied by Western Blot and real-time fluorescent quantitative PCR assays.4?The upstream regulatory mechanisms of PEG 10 were explored and confirmed by ChIP,EMSA,and Double luciferase reporter gene assays,and the association between PEG10 expression and upstream regulatory factors expression was analyzed by immunohistochemistry staining and correlation analysis.5?Elisa assay was performed to detect the concentration of PEG 10 in plasma form pancreatic cancer patients and healthy controls;and the diagnostic role of PEG10 was evaluated by receiver operating characteristic(ROC)curve.Results:1?PEG10 was abnormally overexpressed in pancreatic cancer samples,and the overexpression of PEG 10 was positively associated with blood vessel invasion and Ki-67 expression;PEG10 overexpression was significantly associated with the poor prognosis of patients with pancreatic cancer,and PEG 10 was an independent prognostic factor for such cancer.2?The interference and over expression of PEG 10 in pancreatic cancer cells could respectively inhibit and promote the cancer cell proliferation,migration,and invasion.3?PEG 10 interference could suppress the proliferation of cancer cell by p21 and p27 overexpression induced G0/G1 cycle phase arrest;and PEG 10 knockdown could inhibit the migration and invasion of cancer cells by ERK1/2-MMP7 pathway downregulation.PEG 10 overexpression showed the opposite tendency.4?E2F-1 could directly increase the expression of PEG10 by binding to the promotor region of this molecule.And the expression of E2F-1 in pancreatic cancer tissues was positively associated with that of PEG10.5?The concentration of PEG 10 was significantly higher in plasma from pancreatic cancer patients than that from healthy controls,and the concentration was decreased in the seventlh day following surgery.Furthermore,the increased concentration of PEG 10 was observed in patients at each stage,and the concentration of PEG 10 was higher in metastatic cancer patients.Conclusion:1?PEG 10 was aberrantly overexpressed in pancreatic cancer tissues,and PEG 10 overexpression was markedly associated with the progression and prognosis of this cancer.2?The interference of PEG10 in cancer cells could induce G0/G1 arrest by upregulation of p21 and p27;and ERK/MMP7 pathway may mediate the PEG 10 induced migration and invasion of cancer cells.3?The regulation of PEG 10 was directly controlled by the transcription factor E2F-1.4?PEG10 in the plasma could be considered as a diagnostic biomarker for pancreatic cancer,including early stage cancer.