Knockdown of lncRNA NEAT1 inhibits Th17/CD4 + T cell differentiation through reducing the STAT3 protein level

Interleukin-17 (IL-17)-producing helper T (TH) cells, named as TH(IL-17), TH17, or inflammatory TH (THi), have been recently identified as a novel effector lineage. However, how cytokine signals mediate THi differentiation is unclear. We found that IL-6 functioned to up-regulate IL-23R and that IL-23 synergized with IL-6 in promoting THi generation. STAT3, activated by both IL-6 and IL-23, plays a critical role in THi development. A hyperactive form of STAT3 promoted THi development, whereas this differentiation process was greatly impaired in STAT3-deficient T cells. Moreover, STAT3 regulated the expression of retinoic acid receptor-related orphan receptor gamma-T (RORgamma t), a THi-specific transcriptional regulator; STAT3 deficiency impaired RORgamma t expression and led to elevated expression of T-box expressed in T cells (T-bet) and Forkhead box P3 (Foxp3). Our data thus demonstrate a pathway whereby cytokines regulate THi differentiation through a selective STAT transcription factor that functions to regulate lineage-specific gene expression.

Purpose: Long noncoding RNAs have been implicated in gliomagenesis, but their mechanisms of action are mainly undocumented. Through public glioma mRNA expression data sets, we found thatNEAT1was a potential oncogene. We systematically analyzed the clinical significance and mechanism ofNEAT1in glioblastoma.Experimental Design:Initially, we evaluated whetherNEAT1expression levels could be regulated by EGFR pathway activity. We subsequently evaluated the effect ofNEAT1on the WNT/β-catenin pathway and its target binding gene. The animal model supported the experimental findings.Results:We found thatNEAT1levels were regulated by EGFR pathway activity, which was mediated by STAT3 and NFκB (p65) downstream of the EGFR pathway. Moreover, we found thatNEAT1was critical for glioma cell growth and invasion by increasing β-catenin nuclear transport and downregulating ICAT, GSK3B, and Axin2. Taken together, we found thatNEAT1could bind to EZH2 and mediate the trimethylation of H3K27 in their promoters.NEAT1depletion also inhibited GBM cell growth and invasion in the intracranial animal model.Conclusions:The EGFR/NEAT1/EZH2/β-catenin axis serves as a critical effector of tumorigenesis and progression, suggesting new therapeutic directions in glioblastoma.Clin Cancer Res; 24(3); 684-95. ©2017 AACR.

Background The 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. Methods To 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. Results NEAT1 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. Conclusions Our 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 material The online version of this article (10.1186/s13045-018-0656-7) contains supplementary material, which is available to authorized users.