Exploration Of The Interaction Mechanism Of IL-17 And Notch Signaling Pathways In Pancreatic Cancer

IntroductionPancreatic cancer is highly malignant.Its early diagnosis is difficult and the treatments are not satisfactory.As a concequence,the mortality rate of pancreatic cancer remains high.In the progression of pancreatic cancer,a large number of signaling pathways are abnormaly activated or inactivated.This can be caused by the accumulation of somatic mutations,as well as regulated by other signaling pathways.At the same time,chronic pancreatitis is one of the risk factors of pancreatic cancer.The infiltrated immune cells and varies of cytokines during the inflammatory state may play an important role in regulating immune state of tumor microenvironment and the biological behavior.This study focused on the function and interaction of IL-17A and Notch signaling pathway during the occurrence and progression of pancreatic cancer.In order to enrich the "Inflammation-Cancer Transformation" theory,and to provide theoretical and experimental basis for combined utilization of these two pathways’ inhibitors to treat pancreatic cancer.MethodsThree pancreatic cancer cell lines,MiaPaCa-2,PANC-1 and BxPC-3,were used during the experiment.We incubated them with Notch pathway inhibitor DAPT or recombinant IL-17A factor to suppress or stimulate these two signaling pathways respectively.By proceeding CCK-8,AnnexinV-PI,transwell and tumorsphere experiment,we investigated the impact of Notch and IL-17A pathway on biological behavior of pancreatic cancer cell.And to verify the regulation of IL-17A on Notch signaling pathway via qPCR and Western Blot.ResultsDAPT can inhibit the expression and translation of HES1,HEY1 and HEY2,which are target factors of Notch signaling pathway.In other words,DAPT can down-regulate Notch pathway.As for biological behavior,Notch signaling pathway can promote the proliferation of pancreatic cell,inhibit its apoptosis,accelerate the migration and also play an important role in maintaining the stem-cell-related characteristics.IL-17A factor,on the other hand,can also promote the proliferation and inhibit the apoptosis of pancreatic cancer cells.It shares a dose-dependent role in"epidermal mesenchymal transition(EMT)" process,and may increase the ability of tumorsphere to a certain extent in vitro.IL-17A factor can also upregulate the expression of multiple receptors and ligands in Notch signaling pathway.And may increase the intensity of Notch signaling pathway via NICD-RBPJk-MAML dependent and/or independent pathway.ConclusionsNotch signaling pathway and IL-17A signaling pathway can increase the malignancy of pancreatic cancer cells separately.The continuous secretion of IL-17A factor by Th17 cells,in vivo,may upregulate Notch signaling pathway,as well as its ligands and receptors in pancreatic cancer cell.They may synergistically improve the malignancy of pancreatic cancer cells,and advance the development of pancreatic cancer.The result enriches the "Inflammation-Cancer Transformation"theory,and may provide us with potential treatment in treating pancreatic cancer.