T. Horiuchi1,2, H. Shiba1, N. Saito1,2, H. Sugano1,2, Y. Shirai1, R. Iwase1, K. Haruki1, Y. Fujiwara1, R. Mimoto1,3, K. Furukawa1, T. Uwagawa1,4, K. Yoshida3, T. Ohashi2, K. Yanaga1 1The Jikei University School Of Medicine,Department Of Surgery,Tokyo, , Japan 2The Jikei University School Of Medicine,Department Of Gene Therapy, Research Center For Medical Science,Tokyo, , Japan 3The Jikei University School Of Medicine,Department Of Biochemistry,Tokyo, , Japan 4The Jikei University School Of Medicine,Department Of Medical Oncology And Hematology,Tokyo, , Japan
Introduction: Pancreatic cancer is one of the most aggressive cancer and the fourth leading cause of cancer-related death in the United States and fifth in Japan. The standard first-line treatment for the patients with unresectable locally advanced or metastatic pancreatic ductal adenocarcinoma has been gemcitabine therapy. However, the median survival time did not exceed 6.5 months. Thus, it is imperative to identify the molecular mechanism of pancreatic cancer progression in order to develop novel-targeted therapies to improve the overall survival of the patients. DYRK2 is a member of dual-specificity tyrosine phosphorylation-regulated kinases (DYRKs) family that autophosphorylate tyrosine residues in their activation-loop and function as serine/threonine kinases on their substrates. It is reported that DYRK2 directly phosphorylates p53 at Ser46 and induces apoptosis in response to DNA damage. Moreover, the down-regulation of DYRK2 contributes to accelerated proliferation by stabilizing c-Jun and c-Myc. In this study, we assessed the effects of DYRK2 overexpression on the regulation of pancreatic cancer cell viability.
Methods: Flag-tagged DYRK2 was cloned into the pEB multi vector and transfected into human pancreatic cancer cell line, PANC-1. We compared DYRK2 overexpression group with empty vector-transfected group or non-treat group as control. To assess cell viability and examine the underlying molecular events, we performed cell viability MTT assay and Western blot analysis.
Results: DYRK2 expression was markedly decreased in PANC-1 cells. Cell viability in DYRK2 overexpression group was significantly lower than that in empty vector-transfected group (p=0.023). DYRK2 overexpression upregulated the phosphorylation of glycogen synthase kinase (GSK)-3β protein and reduced cyclin D1 expression in PANC-1 cells.
Conclusion: DYRK2 overexpression activated GSK-3β signaling and significantly reduced cell viability of human pancreatic cancer cells.