The long, noncoding RNA (lncRNA) is an important epigenetic regulator with a critical role in human tumors. Here, we aimed to investigate the clinical application and the potential molecular mechanisms of in gastric cancer tumorigenesis and progression. The expression level of was determined by RT-qPCR analysis in 190 pairs of gastric cancer tissues and adjacent normal gastric mucosa tissues (ANT). The biologic functions of were assessed by and functional experiments. RNA protein pull-down assays and LS/MS mass spectrometry analysis were performed to detect and identify the interacting protein FOXM1. Protein-RNA immunoprecipitation assays were conducted to examine the interaction of FOXM1 and Chromatin immunoprecipitation (ChIP) and luciferase analyses were utilized to identify the binding site of FOXM1 on the promoter. The lncRNA was significantly upregulated in gastric cancer tissues compared with ANTs. High expression of predicted poor prognosis in patients with gastric cancer. enhanced gastric cancer cell proliferation and invasion and directly bound FOXM1 protein and increased FOXM1 posttranslationally. Moreover, is also a FOXM1-responsive lncRNA, and FOXM1 directly binds to the promoter to activate its transcription. Finally, fulfilled its oncogenic functions in a FOXM1-mediated manner. Our study suggests that promotes tumor progression by interacting with FOXM1. may be a valuable prognostic predictor for gastric cancer, and the positive feedback loop of -FOXM1 could be a therapeutic target in pharmacologic strategies..

BackgroundThe long noncoding RNA nuclear-enriched abundant transcript 1 (NEAT1) has been reported to be overexpressed in colorectal cancer (CRC). However, its underlying mechanisms in the progression of CRC have not been well studied.MethodsTo investigate the clinical significance of NEAT1, we analyzed its expression levels in a publicly available dataset and in 71 CRC samples from Fudan University Shanghai Cancer Center. Functional assays, including the CCK8, EdU, colony formation, wound healing, and Transwell assays, were used to determine the oncogenic role of NEAT1 in human CRC progression. Furthermore, RNA pull-down, mass spectrometry, RNA immunoprecipitation, and Dual-Luciferase Reporter Assays were used to determine the mechanism of NEAT1 in CRC progression. Animal experiments were used to determine the role of NEAT1 in CRC tumorigenicity and metastasis in vivo.ResultsNEAT1 expression was significantly upregulated in CRC tissues compared with its expression in normal tissues. Altered NEAT1 expression led to marked changes in proliferation, migration, and invasion of CRC cells both in vitro and in vivo. Mechanistically, we found that NEAT1 directly bound to the DDX5 protein, regulated its stability, and sequentially activated Wnt signaling. Our study showed that NEAT1 indirectly activated the Wnt/β-catenin signaling pathway via DDX5 and fulfilled its oncogenic functions in a DDX5-mediated manner. Clinically, concomitant NEAT1 and DDX5 protein levels negatively correlated with the overall survival and disease-free survival of CRC patients.ConclusionsOur findings indicated that NEAT1 activated Wnt signaling to promote colorectal cancer progression and metastasis. The NEAT1/DDX5/Wnt/β-catenin axis could be a potential therapeutic target of pharmacological strategies.Electronic supplementary materialThe online version of this article (10.1186/s13045-018-0656-7) contains supplementary material, which is available to authorized users.

Ubiquitination is essential for regulation of cell physiology, protein stability, and signal transduction [1]. Its dysregulation is an important factor in many diseases, including cancer. We explored the potential OTUB1-catalyzed deubiquitination of FOXM1, a transcription factor linked to carcinogenesis, and the biological consequence of that interaction in ovarian cancer. We found that FOXM1 is ubiquitinated by multiple polyUb chains and targeted for proteosomal degradation in a reaction dependent on its ubiquitination-required KEN box. Additionally, the OTUB1 N-terminus and catalytic triad bind to FOXM1, specifically catalyzing cleavage of the K48-specific ubiquitin linkage from FOXM1. Moreover, OTUB1-FOXM1 interaction drives tumor progression and OTUB1 expression predicts a poor prognosis in ovarian cancer. Our study suggests that inhibiting OTUB1-FOXM1 interaction is a potential new avenue for ovarian cancer therapy.