Pro-inflammatory Stimulus Facilitates GBM Growth Via The EZH2/SP1/MCM3 Axis

Objective: Glioblastoma multiforme(GBM)is the most common and aggressive type of brain tumor with poor survival due to the high heterogeneous and infiltrative nature.It is extremely urgent to find new and effective therapeutic targets.The inflammatory microenvironment and uncontrolled growth are considered to be two major features of GBM,and the inflammatory microenvironment has been shown to promote glioma growth,but the underlying mechanisms are currently unclear.This study aimed to investigate whether the oncogene EZH2 mediates the promotion of pro-inflammatory microenvironment on GBM and explore the underlying mechanisms.Methods: The pro-inflammatory microenvironment of late GBM was mimicked by stimulating GBM cells with LPS plus IFN-?.Cell viability,cell cycle and proliferation were determined by CCK-8,flow cytometry and colony formation assay.Expression of mRNAs and protein were evaluated by q-PCR,western blot and immunostaining.Protein-protein interaction and protein-DNA interaction were detected by Co-IP and Chip assay separately.Results: Pro-inflammatory stimulation promoted GBM cells proliferation and cell cycle progression,EZH2 suppression could block this promotion.Pro-inflammatory stimulation could induce up-regulation and nuclear translocation of EZH2 in GBM cells.Pro-inflammatory activation could strengthen the direct combination of EZH2 with SP1 in nucleus while SP1 could drive transcription of minichromosome maintenance 3(MCM3)by directly binding to its promoter region.In addition,it was demonstrated that EZH2 positively regulate the expression of SP1 and MCM3.In vitro and in vivo experiments also demonstrated that that inhibition of either EZH2 or SP1 could lead to GBM growth control.Conclusions: Our results demonstrate that the EZH2-SP1-MCM3 axis contributes to pro-inflammatory stimulation induced GBM growth while blocking of this signaling pathway is beneficial for control of GBM.