ABSTRACT
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.
ABSTRACT
BACKGROUND: Long noncoding RNA small nucleolar RNA host gene 1 (SNHG1) is dysregulated in a variety of tumors. However, little is known of its role in pancreatic cancer (PC). METHODS: The role of SNHG1 on PC cell proliferation, migration, invasion, apoptosis, and the epithelial-mesenchymal transition (EMT) were assessed in vitro using MTT, EDU, wound healing, and Transwell assays, as well as flow cytometry and western blotting. Luciferase reporter assay, western blotting, and qRT-PCR were used to examine SNHG1 regulation. Tumor growth in mice was also investigated. RESULTS: Downregulation of SNHG1 blocked cell proliferation, migration and invasion, and induced apoptosis in vitro, while also inhibiting the EMT, shown by changes in the biomarkers E-cadherin, N-cadherin, and Vimentin. The opposite results were observed on upregulation of SNHG1. In vivo experiments showed that downregulation of SNHG1 inhibited tumor development in nude mice. Furthermore, experiments investigating the regulatory mechanism of SNHG1 indicated that SNHG1 acted as a competitive endogenous RNA, positively regulating the expression of fibroblast growth factor receptor 1 (FGFR1) through sponging miR-497. Rescue experiments demonstrated that the effects of SNHG1 downregulation on PC cells were attenuated when simultaneously inhibiting the levels of miR-497. CONCLUSIONS: SNHG1 upregulates FGFR1 expression by sponging miR-497, which promotes the progression of PC. SNHG1 may thus be a novel target for treating PC.
