Oligoadenylate synthetases-like is a prognostic biomarker and therapeutic target in pancreatic ductal adenocarcinoma

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is fatal cancer that causes death. Early metastasis, resistance to chemotherapy, and lack of treatment contribute to a poor prognosis. Therefore, finding new therapeutic targets and biomarkers is a particularly urgent need to improve the survival of PDAC patients. Oligoadenylate synthetases-like (OASL), an antiviral enzyme produced by interferon (IFN), has been found to be associated with the occurrence and development of multiple cancers. However, its role in PDAC has been less well-studied. The value of OASL in PDAC was evaluated by bioinformatics and in vitro experiments. METHODS: The expression of OASL was evaluated using the Oncomine and Gene Expression Profiling Interactive Analysis (GEPIA) online websites. The survival time was also calculated by GEPIA. The correlation between OASL messenger RNA (mRNA) expression and immune infiltration was analyzed by the Tumor Immune Estimation Resource (TIMER) database. Clinical characteristics were revealed by The Cancer Genome Atlas (TCGA) data. A nomogram and forest plot were constructed based on univariate and multivariate Cox regression. Cell experiments [western blot assays, 3-(4,5-dimethylathiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, transwell assays, flow cytometry assays] were used to verify the value of OASL in PDAC cells (Panc-1, Mia paca-2, and Aspc-1). RESULTS: A higher expression of OASL was observed in PDAC (P<0.05). Patients with increased expression of OASL had worse overall survival (OS; P<0.05) and disease-specific survival (DSS; P<0.05). The expression of OASL was correlated with T stage (P=0.030) and N stage (P=0.004), radiation therapy (P=0.013), primary therapy outcome (P<0.001), residual tumor (P=0.028), and tumor location (P=0.004) by univariate analysis, which also confirmed that OASL was an independent prognostic factor. Moreover, OASL expression was positively associated with neutrophils. In vitro experiments indicated that knockdown of OASL inhibited cell viability and invasion while increasing apoptosis rate. CONCLUSIONS: High expression of OASL is associated with poor prognosis. Targeting OASL delays PDAC tumor progression in vitro. We highlight that OASL is a novel prognostic biomarker and therapeutic target of PDAC.