DDX31: A Novel Functional Oncogene Promotes Migration and Proliferation of Pancreatic Cancer

Abstract Purpose: Pancreatic cancer is one of the most malignant cancers with rapid disease progression. Pancreatic ductal adenocarcinoma (PDAC) accounts for more than 90% in exocrine pancreatic cancer. DDX31 is one of the Asp-Glu-Ala-Asp (DEAD)-box RNA helicases (DDX) family member, which has never been reported in pancreatic ductal adenocarcinoma. Through comprehensive analysis of bioinformatics screening, clinical pathological data and experiment results verification, we found DDX31 may be a promising oncogene.Patients and methods: The potential correlation between DDX3 expression and clinical feature of PDAC was analyzed, which revealed that patients with high DDX31 expression may have a poor prognosis. Elevated expression levels of DDX31 in PDAC compared with adjacent normal tissues were determined by immunohistochemical and Western blot analyses. Western blot analysis of N-cadherin, Snail, transwell, and wound healing assays was carried out to evaluate the pro-metastasis effects of DDX31 in PDAC. In vitro experiments included colony formation assay. Edu labeling assay, CCK-8, western blot analysis of Ki67, PCNA, and an in vivo subcutaneous mouse model were used to analyze the role of DDX31 in PDAC proliferation.Results: In our research, integrated bioinformatics analysis of the TCGA and GEO databases was performed to identify the metastasis and proliferation-related differentially expressed genes (DEG). DDX31 predicts strong metastasis and proliferation capacity of PDAC, was finally screened. Then, the clinical data identified that highexpression-DDX31 was correlated with pancreatic tumor size, pathological grade, and lymph node metastasis. The in vitro and vivo experiments revealed that overexpression-DDX31 promoted the migration, proliferation and cell viability of pancreatic cancer cells, these functions of DDX31 had also been proved in the knockdown results. Moreover, the EMT related markers and proliferation markers were identified to be positively regulated by DDX31 in pancreatic cancer cells.Conclusion: Thus, our work uncovered that DDX31 promotes migration and proliferation in PDAC and might be a promising therapeutic target in pancreatic cancer.