Dataset Information

Histone demethylase KDM4D promotes gastrointestinal stromal tumor progression through HIF1?/VEGFA signalling.

ABSTRACT:

Background

Gastrointestinal stromal tumour (GIST) is the most common soft tissue sarcoma. The identification of the molecular mechanisms regulating GIST progression is vital for its treatment and prevention. Increasing reports have demonstrated that epigenetic alterations play critical roles in GIST development. However, the role of the histone demethylase KDM4D in GIST progression is poorly understood.

Methods

In clinically matched GIST tissues, KDM4D protein levels were measured by Western blot and immunohistochemical (IHC) staining. KDM4D mRNA levels were examined by quantitative real-time PCR (qRT-PCR). Bioinformatics analysis was used to examine KDM4D expression. The biological effects of KDM4D were investigated in vitro using CCK-8, BrdU/PI, wound healing, colony formation, tube formation and Transwell assays and in vivo using a xenograft mice model. Luciferase assays were used to assess regulation of HIF1? gene promoter activity by KDM4D. ChIP assays were performed to assess KDM4D, H3K36me3 and H3K9me3 occupancy on the HIF1? gene promoter.

Results

We observed a significant upregulation of KDM4D in GIST tissue compared with matched normal tissue and further explored the oncogenic function of KDM4D both in vitro and in vivo. Furthermore, we demonstrated that KDM4D directly interacted with the HIF1? gene promoter and regulated its activity, promoting tumour angiogenesis and GIST progression both in vitro and in vivo. Finally, we demonstrated that KDM4D transcriptionally activates HIF1? expression via H3K9me3 and H3K36me3 demethylation at the promoter region.

Conclusions

Our findings reveal the important roles of the KDM4D/HIF1?/VEGFA signalling pathway in GIST progression, and this pathway may act as a potential therapeutic target for GIST patients.

SUBMITTER: Hu F

PROVIDER: S-EPMC6065154 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature

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Project description:BackgroundAccumulating evidence has revealed the pivotal role of epigenetic regulation in the pathogenesis of liver disease. However, the epigenetic mechanism that accounts for hepatic stellate cells (HSCs) activation in liver fibrosis remains largely unknown.MethodsPrimary HSCs were used to screen the differentially expressed histone H3 lysine methyltransferases and demethylases during HSC activation. Loss-of-function experiments were applied to determine the cellular functions of KDM4D in HSCs. Transcriptome analysis was applied to explore the downstream targets of KDM4D. Real-time qPCR, western blotting, immunohistochemical staining, and chromatin immunoprecipitation were performed to uncover the underlying mechanism concerning KDM4D during liver fibrogenesis.FindingsKDM4D was identified as a remarkable up-regulated histone H3 demethylase during HSC activation. The overexpression profile of KDM4D was confirmed in three fibrosis animal models and human fibrotic liver tissues. In vitro Kdm4d knockdown impaired the collagen gel contraction and migration capacity of primary HSCs. In established CCl4-induced mice model, Kdm4d knockdown inhibited fibrosis progression, and promoted fibrosis reversal, with enhanced thinning and splitting of fibrotic septa, as well as a dramatic decrease in collagen area. Whole gene transcriptome analysis showed the regulatory role of KDM4D in Toll-Like Receptor (TLR) signaling pathway. Mechanistically, KDM4D catalyzed histone 3 on lysine 9 (H3K9) di-, and tri-demethylation, which promoted TLR4 expression, and subsequently prompted liver fibrogenesis by activating NF-κB signaling pathways.InterpretationKDM4D facilitates TLR4 transcription through demethylation of H3K9, thus activating TLR4/NF-κB signaling pathways in HSCs, contributing to HSC activation and collagen crosslinking, further, hepatic fibrosis progression. FUND: Shanghai New Hundred Talents Program, Shanghai Municipal Commission of Health and Family Planning, Key Developing Disciplines Program, Shanghai Key disciplines program of Health and Family Planning and Shanghai Sailing Program.