Role And Mechanism Of TRIP6in Pancreatic Cancer Progression

Pancreatic cancer is a disease lack of early clinical symptoms and usually diagnosedat late stages with high mortality.An estimated227000deaths result from pancreaticcancer worldwide each year. Pancreatic cancer morbidity has been gradually increasingduring the last decade. The1-and5-year survival rates for pancreatic cancer are about25%and5%, respectively, which are the lowest survival rates of all major cancers. Lack ofappropriate markers for early diagnosis, dissemination to distant sites in early stages, andineffective treatments for late stages of disease lead to poor prognosis for patients withpancreatic cancer. So seeking warning factor for early diagnosis and exploring effectivetreatments are the focus on the research of the pathogenesis of pancreatic cancer.Perineural invasion (PNI) is a process whereby cancer cells invade the surroundingnerves, PNI thus providing an alternative route for metastatic spread to the adjacent tissueor organsand pain generation.PNI has been shown to be an important prognostic factor inmany types of human malignancies. PNI is one of the established prognostic factors inpancreatic carcinoma.Perineural tumor invasion of intrapancreatic nerves, and tumormetastases along extrapancreatic nerves are key features of pancreatic malignancies. Thepreasent of PNI means that the tumor was progressed and the patients had poorprognosis. In order to improve the early diagnosis of pancreatic cancer and the prognosis,the exact mechanism of pancreatic cancer with PNI needs further investigation.Thyroid hormone receptor interactor6(TRIP6) is an adaptor protein and focaladhesion molecule that belongs to the zyxin family. TRIP6serves as a platform for therecruitment of a wide variety of signaling molecules involved in cell migration andinvasion, anti-apoptosis and transcription regulation. TRIP6can be detected in differentcarcinomas including glioblastoma, nasopharyngeal carcinoma and Ewing sarcoma.Although TRIP6has been implicated in tumorigenesis, the underlying mechanism remainslargely unknown.So the aims of the present study are to investigate:1) whether TRIP6is associatedwith the progression of pancreatic cancer and PNI;2) whether TRIP6might be a warningfactor for early diagnosis of pancreatic cancer;3) whether TRIP6may be a useful target ofhuman gene therapy for pancreatic cancer. 1.The expression of TRIP6in different cell lines of humanpancreatic cancerObjective:The expression of TRIP6was detected in various human pancreatic cancercell lines,which wasThe different expression among the three human pancreatic cancer celllines were observed. Preliminary explore the relationship between the expression of TRIP6with the ability of perineural invasion in different human pancreatic cancercell lines.Methods:TRIP6mRNA and protein expression were detected in three differentpancreatic cancer cell lines including CaPan-2(high perineural invasion group), Panc-1(low perineural invasion group) and SW1990human pancreatic cancer cell line(controlgroup) by using RT-PCR and western-blot. The relationship between the differentexpression level of TRIP6and various characteristics of the cell lines was analyzed.Results: The expression of TRIP6mRNA in Capan-2was significantly higher thanthat in Panc-1and SW1990cell lines. The expression of TRIP6protein in Capan-2wasremarkable, while that of in another cell lines was not be detected.Conclusion: TRIP6mRNA and protein expression were markedly higher in CaPan-2(high perineural invasion group) cell line, which suggests that TRIP6might be associatedwith the progress of pancreatic cancer and PNI.2.Establishment of an animal model of pancreaticcarcinoma with perineural invasionObjective: Toestablish an animal model which is easily operated, highly replicatedand relatively stable by injecting pancreatic cancer cell lines to the peripheral region ofsciatic nerve of nudes.Methods: Three different pancreatic cancer cell lines including CaPan-2, Panc-1andSW1990and three different injection methods including percutaneous injection aroundsciatic nerve, positioning injection around sciatic nerve by surgical incision, wrapping thesciatic nerve by Matrigel and human cell suspension were used to compare thedifference of tumorigenesis and incidence of PNI.Results:(1).The weight of nude mice implanted tumor decreased compared withcontrol group.(2). Among the three different injection methods, percutaneous injectionaround sciatic nerve achieved the lowest incidence of PNI while wrapping the sciatic nerve by Matrigel and human cell suspension is better than others.(3)the animal injected withthe SW1990cell line had the shortest tumorigenic time while those injected with thePanc-1cell line has the longest tumorigenic time among different animal models. Theincidence of PNI was the highest by using Capan-2cell line and the lowest by usingPanc-1cell line among different animal models.Conclusion: All these three cell lines can be used to establish a relative stable PNIanimal model but different cell line should be choosed according to different objectives ofexperiment.3.The expression of TRIP6in PNI animal modelObjective:To further investigate the role of TRIP6in the progression of pancreaticcancer and arise of PNI.Methods:Through wrapping the sciatic nerve by Matrigel and human cellsuspensionmodeling and Capan-2cell line were used to establish PNI anmialmodel.Non-PNI animal model was established by subcutaneously injecting Capan-2cellline into nude mice.The expression of TRIP6was examined by molecular biologytechniques and immunohistochemistry in different issues and groups.Results:(1). TRIP6were not detected in nomal pancreatic and nerve.The expressionof TRIP6in sciatic nerve injection group was higher than that in subcutaneousgroup.(2).The result of immunohistochemistry showed that TRIP6was mainly expressed inthe cytoplasmand peripheral nerve envisioned by cancer cell was highly expressed byTRIP6.Conclusion:TRIP6was not detected in nomal pancreatic and nerve but onlyexpressed in tumor. The expression level of TRIP6was higher in PNI group than that innon-PNI group, which further suggested that TRIP6can regulate the metastasis ofpancreatic cancer.4.Effects on human pancreatic cancer cell lines throughinhibited the expression of TRIP6Objective:Observed the change of migration,invasion and apoptosis of humanpancreatic cancer cell line after inhibited the expression of TRIP6,further explore the roleof TRIP6in the progression of pancreatic cancer.Methods: Capan-2and Panc-1cell lines were treated with TRIP6siRNA. Cell migration assays were performed by using Costar Transwell migration chambers.Matrigel invasion chamber were used to detect cell invasiveness. Apoptosis wasmeasured by flow cytometry.Results:(1). TRIP6mRNA and protein expression level were declined after siRNAtransient transfection.(2). Inhibition the expression of TRIP6in human pancreatic cancercell line increased cell migration, cell invasion and cell apoptosis, especially in the earlystages of apoptosis.Conclusion: These data suggest that TRIP6contributes to pancreatic carcinogenesisand perineural infiltration by increasing cellular motility and invasiveness and inhibitingcell apoptosis.