Effects Of Wnt5a Pathway On The Invasioii And Metastasis Of Pancreatic Cancer

Research Background: The pancreatic cancer (PC) is a malignant tumor of digestivesystem that occurs on exocrine gland of pancreas, accounting for1%-4%of systemicmlignant tumor. More than90%of PC is pancreatic ductal adenocarinoma. One yearsurvival rate of PC is8%,5year survival rate is less than5%, the median survival time isonly4-6months, and the mortality ranks the8th in malignant tumors. The aggressivenature of this neoplasia, the lack of methods for early detection, and the limited response toavailable treatments contribute to its high mortality rate. Therefore, early diagnosis andtreatment of pancreatic cancer is still facing a severe test.Wnt5a is1of19Wnt proteins that make up the family of secreted lipid-modifiedglycoproteins that show a highly regulated pattern of expression and has distinct rolesduring development and tissue homoeostasis. Wnt5a is one of the most highly investigatednon-canonical Wnts and has been implicated in almost all aspects of non-canonical Wntsignalling.Investigations to elucidate the role of Wnt-5a in cancer have shown paradoxicalresults. Studies indicate that it may have a tumour suppressing or an oncogenic effectdepending on the cancer type. A large number of studies have indicated that Wnt5acommands a tumour-suppressing effect, and it was shown to be downregulated in a numberof different cancers such as colorectal cancer, neuroblastoma, ductal breast cancer andleukaemias. Downregulation of Wnt5a has been associated with higher tumour grade andwas shown to be an independent factor in dicating poor prognosis in a number of differenttumour subtypes. Although there is firm evidence that Wnt5a has a tumour-suppressiverole, a few studies have pointed to Wnt5a having an oncogenic role in tumours arisingfrom a variety of different tissues. Increased expression of Wnt5a, a hallmark ofoncogenesis, was identified in melanoma skin cancer, breast cancer cells, gastric cancer,non-small-cell lung cancer and prostate cancer. Thus an account of the Wnt5a cellular andsignalling context should be taken before a functional classification can be made.Inpancreatic cancer there are different reports about Wnt5a expression. It's necessary tostudy the expression, function and mechanisms of Wnt5a in pancreatic cancer.Objective: To determine the expression and function of Wnt5a in pancreatic cancerand preliminary research the mechanism of Wnt5a signaling pathway. Methods:○1Immunohistochemistry of the tissue microarray was used to analyze theexpression of Wnt5a in pancreatic cancer;○2built Wnt5a overexpression and interferencevectors,stably transfected human pancreatic cancer cellline(PANC-1, BXPC-3);○3Cellgrowth curve,flow cytometry analysis, Acumen explore analysis, Wound Healing Assays,transwell test, colony formation and orthotopic implantation technique in nude micepancreas were used to analyze changes of biogical behavior of transfected cells.○4detected the expression of mRNA and protein of Wnt5a pathway using real timequantitative PCR and Western-Blot.Results:○1Immunohistochemistry of the tissue microarray showed a characteristicdifferential expression of Wnt5a in pancreatic cancer and normal tissues.22of134normalpancreas samples stained positive for Wnt5a, whereas109of134pancreatic cancersexhibit strong positive immunostaining for Wnt5a. In contrast, in poorly differentiatedpancreatic cancer Wnt5a immunostaining was partly lost. Clinicopathological parametersanalysis showed downregulation of Wnt5a has been associated with higher tumour grade.○2Comparion between cell line transfected with Wnt5a overexpression and interferencevectors and that of empty vector group has shown: overexpression of Wnt5a promoted cellproliferation, colonogenicity, migration, and invasion, while reducing Wnt5a expressiondecreased proliferation, colonogenicity, migration, and invasion;○3Orthotopicimplantation in nude mice pancreas has shown: PANC-1cell transfected with Wnt5aoverexpression vectors increasd in cell proliferation and invasion.○4EMT relationalProtein expression level was detected by Western-Blot.It showed Wnt5a stimulates anincrease in Vimentin and Snail protein expression and decrease E-cadherin expression inpancreatic cancer cell line; By Real time quantitative PCR, We found mRNA level ofVimentin and E-cadherin gene wre consistent with protein level in BXPC-3cellline, butnot Snail.Conclusion:○1The pancreatic cancer and nomal pancreatic tissue have differentWnt5a expression level；○2Overexpression of Wnt5a promoted cell proliferation,colonogenicity, migration and invasion while reducing Wnt5a expression decreasedproliferation, colonogenicity, migration,and invasion;○3Wnt5a promoted cell migrationand invasion through EMT.