The Expression And Biological Significance Of TNIK In Pancreatic Cancer

Background:Pancreatic cancer belongs to digestive maligncacies threatening peoples" health and life. It is more malignant with worse prognosis and shorter survival time in despite of its lower incidence compared with other digestive cancers. Most patients with pancreatic cancer were diagnosed at the advanced stage due to its special anatomical position and lack of typical clinical manifestations, and lost the opportunity for operating on. Only10-20%patients could receive operations. Even so, the5-year survival time after sugery is merely up to15-25%. Therefore, something must be done to find novel target in genetic molecular level which plays an important role in prevention, diagnosis, treatment and prognostic evaluation of pancreatic cancer. TNIK, a member of MAP4K family, activates its downstream substrates by phosphorylation and plays an important role in promoting proliferation, invasion and inhibiting apoptosis. Therefore, TNIK closely correlated with the carcinogenesis of colorectal, gastric and breast cancer. However, Little information is available on the association of TNIK and pancreatic carcinogenesis.Objective:1. To investigate the differential expression of TNIK among pancreatic cancer tissue and paired adjacent tissue by qPCR and Western blot methods; To investigate the relationship between TNIK expression and clinicopathologic characteristics, prognosis in pancreatic cancer.2. To screen the highest cell lines in TNIK expression among AsPC-1、BxPC-3、MiaPaca-2and Panc-1and the most effective SiRNA.3. To investigate the role of TNIK in the carcinogenesis and progression of pancreatic cancerMethod:1. The expression of TNIK between10pair of cancerous and paratumoral tissues was detected by qPCR and Western blot at mRNA and protein level, respectively; the expression of TNIK in91paraffin-embedded pancreatic tissues was detected by immunohistochemistry (IHC). The related data were analyzed by statistics in order to make sure the relationship of TNIK expression and clinicopathologic features, prognosis in pancreatic cncer.2. We used qPCR and Western blot methods to test the difference in TNIK expression among AsPC-1、 BxPC-3、MiaPaca-2and Panc-1pancreatic cell lines. Subsequently, TNIK targeted SiRNAs (SiRNA-1, SiRNA-2SiRNA-3), NC, PC and Vector groups were transfected into the previously tested pancreatic cell lines, respectively.3. The previously tested SiRNA, NC and Vector groups were respectively transfected into the pancreatic cell lines, and then we applied MTT、Transwell、Cell Scratch Wound and V-FITC+PI double labeling methods to detect the changes in proliferation, invasion, migration and apoptosis to make sure the exact role of TNIK in pancreatic carcinogenesis.Results:1. Compared with paired paratumoral tissues, the aberrant expression of TNIK at mRNA and protein level was observed in cancerous tissues (P=0.028, P<0.0l, respectively); In addition, the TNIK expression was associated with UICC pathologic stage (P=0.040) and T status (.P=0.045). Cox Univariate model analysis revealed that patients with high TNIK showed a shorter OS (Overall survival) and DFS (Disease free survival) compared with those with low TNIK (P=0.021, P=0.031, respectively). By contrast, Cox multivariate model analysis demonstrated that no significant difference was found between patients with high and low TNIK neither in OS or DFS (P>0.05).2. The Panc-1had the highest expression of TNIK among the4pancreatic cell lines. Meanwhile, SiRNA-3was observed to possess the most effective silencing effect, and its silencing effect is up to78.7±4.5%.3. After Panc-1cell line was treated by the SiRNA-3targeted TNIK, its proliferative, invasive and migrating biological properties greatly diminished, while the cell apoptosis remarkably increased.Conelusion:1. TNIK was aberrantly expressed in pancreatic cancer tissues, and its expression was associated with UICC pathologic stage and T status. Additionally, aberrant expression of TNIK is a poor prognostic factor, but not an independent poor prognostic factor in pancreatic cancer after surgery. Pathologic stage is an independent prognostic factor affecting OS, and the status of distant metastasis is an independent prognostic factor affecting DFS in pancreatic cancer after surgery.2. TNIK promotes proliferation, invasion and migration, and inhibits cell apoptosis simultaneously in the carcinogenesis and progression of pancreatic cancer.