EZH2 suppression in glioblastoma shifts microglia toward M1 phenotype in tumor microenvironment

Abstract

BackgroundGlioblastoma multiforme (GBM) induces tumor immunosuppression through interacting with tumor-infiltrating microglia or macrophages (TAMs) with an unclear pathogenesis. Enhancer of zeste homolog 2 (EZH2) is abundant in GBM samples and cell lines and is involved in GBM proliferation, cell cycle, and invasion, whereas its association with innate immune response is not yet reported. Herein, the aim of this study was to investigate the role of EZH2 in GBM immune.MethodsCo-culturing models of human/murine GBM cells with PBMC-derived macrophages/primary microglia were employed. EZH2 mRNAs and function were suppressed by siEZH2 and DZNep. Real-time PCR and flow cytometry were used to determine levels of microglia/macrophages markers. The fluorescence-labeled latex beads and flow cytometry were utilized to evaluate phagocytic abilities of microglia. CCK8 assay was performed to assess microglia proliferation.ResultsEZH2 inhibition led to significant reduction of TGFβ1-3 and IL10 and elevation of IL1β and IL6 in human and murine GBM cells. More importantly, EZH2 suppression in GBM cells resulted in significant increase of M1 markers (TNFα and iNOS) and decrease of a pool of M2 markers in murine microglia. The proportion of CD206+ cells was decreased in PBMC-derived macrophages as co-incubated with EZH2-inhibited GBM cells. Functional researches showed that phagocytic capacities of microglia were significantly ameliorated after EZH2 inhibition in co-culturing GBM cells and microglia proliferation was declined after addition of TGFβ2 antibodies to co-incubated GBM cells with EZH2 inhibition. Besides, we found that EZH2 suppression in GBM cells enhanced co-culturing microglia engulfment through activation of iNOS.ConclusionsOur data demonstrates that EZH2 participates in GBM-induced immune deficient and EZH2 suppression in GBM can remodel microglia immune functions, which is beneficial for understanding GBM pathogenesis and suggests potential targets for therapeutic approaches.Electronic supplementary materialThe online version of this article (10.1186/s12974-017-0993-4) contains supplementary material, which is available to authorized users.

Construction of a circRNA-miRNA-mRNA Network Related to Macrophage Infiltration in Hepatocellular Carcinoma

“…Among the six hub DEmRNAs, EZH2 has been demonstrated to be highly expressed in HCC, and injection of EZH2 inhibitor GSK126 induces CXCL10 production from macrophages and causes plasma cell polarization, inhibition of the antitumor T cell response, and hepatoma growth (Wei et al, 2019). Additionally, inhibition of EZH2 is also able to affect the macrophage activity in some other cancer types, such as suppressing macrophage infiltration in lung cancer and shifting microglia toward the M1 phenotype in glioblastoma (Yin et al, 2017;Xia et al, 2019). Although the role of DTL, PRC1, KIF4A, ITGA6, and LAMC1 in the regulation of HCC-related macrophages remains unknown, the findings of the mentioned hub DEmRNAs in the regulation of macrophage activity in other diseases may provide the clues for HCC.…”

Targeting Tumor Associated Macrophages to Overcome Conventional Treatment Resistance in Glioblastoma

“…Resident microglia are also involved in antitumor immunity processes through the expression of toll-like receptor 2 (TLR2) that down regulates their major histocompatibility complex class II (MHCII) expression . In a murine model, enhancer of zeste homolog 2 (EZH2) expression in GB was shown to be involved in the polarization of TAMs toward the M2 phenotype, creating an immune deficient environment (Yin et al, 2017). A 6 cytokine-related gene signature in resident microglia was shown to be sufficient to predict survival and identify M2 cells in GB (Cai et al, 2015).…”

Immune changes in peripheral blood and hematoma of patients with intracerebral hemorrhage

“…26,27 In addition, in humans, CD86 and CD206 are markers of pro-inflammatory M1-like and anti-inflammatory M2-like M/MΦ, respectively. [28][29][30] Therefore, we used CD45 low CD11b + CD86 + as a marker of M1 microglia and CD45 low CD11b + CD206 + as a marker of M2 microglia. CD11b + and CD45 high are general markers of macrophages, and CD86 and CD206 are markers of M1and M2-like macrophages, respectively.…”