Targeting STAT3 Impairs Tumor Invasion And Metastasis Through Modulating EZH2/miR-200b/a/429Axis In Human HNSCC

Head and neck squamous cell carcinoma in a highy prevalence rate around the world.Due to the tumor often occurred local invasion and metastasis,patients prognosis is poor.If we have a better understand of the biology of head and neck squamous carcinoma invasion and metastasis mechanisms,we can find head and neck squamous cell carcinomas biological biological marker.Studies shown that STAT3 and EZH2 have the effect that cause tumor progression in head and neck squamous cell carcinoma.They all can promote the proliferation of HNSCC,and affect the progression of the tumor.STAT3 and EZH2 and negatively correlated with the prognosis of patients with HNSCC.We’d like to know whether STAT3,EZH2 promote invasion and metastasis in HNSCC.So we can find potential therapeutic targets.methodsChapter1: Western blot analysis was employed to assess protein expression.Real-time PCR analysis contrasts the relative expression levels of mi R-200b/a/429 genes.U6 was used as a loading control,and the 2-ΔΔCt method was used to evaluate the relative abundance of genes.Transwell assay and wound-healing assay were used to detect ability of tumor invasion and metastasis.Immunofluorescence staining verify changemengt of HNSCC in phenotype.We performed immunohistochemical stainings to confirm that rusults in vitro assay.Chapter2: To verify tumor establishment,fluorescence images were captured after the injection with an IVIS Lumina Imaging System.Mice were randomly assigned to five groups.DMSO,WP1066,DZNep,NC mimics or mi R-429 mimics was administered by intraperitoneal injection every 3 days for 21 days.Bioluminescence imaging for tumor volume were measured each week,and body weight was measured daily.Finally,the animals were sacrificed by cervical dislocation and the orthotopic tumors were collected for further examination.Tumor specimens were used for IHC and real-time PCR.ResultsWestern blot analysis showed that Treatment with WP1066 potently repressed EZH2,and inhibited EZH2-induced H3K27me3 in HNSCC cell lines.Of interest,IL-6 significantly induced the expression of EZH2,via activating STAT3 phosphorylation.STAT3 depletion significantly impared the invasion and migration capacity of HNSCCs.Abundance of mi R-200b/a/429 before and after treatment with WP1066 was compared using real-time PCR.After WP1066 treatment,both HNSCC cell lines underwent a morphologic change to an epithelial phenotype characterized by cortical F-actin staining together with E-cadherin localization at cell-cell junctions and N-cadherin absence.In contrast,stimuli of IL-6 significantly induced the mesenchymal phenotype.In order to measure such regulation role in HNSCC,we employed EZH2 si RNA which can suppress expression of EZH2.p-STAT3 was also suppressed by silenced EZH2.Moreover,si-EZH2 dramatically elevated expression level of mi R200-b/a/429 genes.Based on transwell and wound healing assays,EZH2 silencing markably inhibited the invasion and migration capacity of HNSCC cell lines Furthermore,our analysis also showed that mesenchymal markers N-cadherin,Twist and Vimentin were downregulated by EZH2 suppression,accompanied with raised E-cadherin.We further employed immunofluorescence staining to directly visualize the effect of EZH2 abrogation on E-cadherin expression,localization,and cell morphology.When we treated SCC25 and CAL27 cells with IL-6 and transfected them with si-EZH2,we found that EZH2 abrogation significantly attenuated the effects of IL-6 on mi R-200b/a/429 in vitro.For each HNSCC cell line,EZH2 depletion significantly compensated STAT3’s oncogenic effect,leading to raised E-cadherin and suppressed N-cadherin.We performed immunofluorescence staining to directly visualize the effect on these EMT markers and cell morphology.After IL-6 activation,si-EZH2-transfected HNSCCs showed epithelial cell features,characterized by a typical cobblestone structure and membrane-localized E-cadherin.Luciferase slow virus infection department of head and neck squamous cancer cells SCC25,intensity of fluorescence to determine success or not,mouth De Jian Li in-situ model in mice.Were given local injection of drugs: DMSO,DZNep,WP1066,mimic NC,mi R-429.And regularly measuring body weight in mice.Through the small animal in vivo imaging system as detecting tumor growth.HE staining to observe tumor cells and form;Immunohistochemical detection of protein expression levels,q-PCR to detect the expression of mi R-200 / a / 429 b level.Understanding of STAT3 in body environment regulation EZH2 / mi R200b/a / 429 shaft impact HNSCC invasion and metastasis.Conclusion1.Inhibition of STAT3 suppresses HNSCC tumor invasion and migration in vitro2.Regulatory role of EZH2/mi R-200/b/a/429 axis in the EMT process of HNSCC3.STAT3 expression was associated with increased EZH2,decreased mi R-200b/a/429 and enhanced tumor motility in HNSCC4.EZH2 silencing counteracts STAT3 overexpression in HNSCC cells in vitro5.STAT3 inhibitors can effectively inhibit EZH2 / mi R200b/a / 429 axis in vivo.6.DZNep environment inhibit mi R200b/a / 429 in vivo.7.UP-regultaion of mi R-b/a/429 markably suppressed tumor rogression in vivo.