| Glioblastoma(GBM)is one of the most common primary central nervous system tumors cancer cells can quickly switch their migration mode,so blocking glioma cell invasion has always been a challenge.Seeking drugs that can block multiple migration modes is an urgent problem to be solved.In the previous experiment,we found that the small molecule 2-(1H-indole-3-carbonyl)-thiazole-4-carboxylic acid methyl ester(ITE),an endogenous Aryl Hydrocarbon Receptor(AHR)agonist,can block more than one mode of glioma cell migration.In order to determine the genes that mediated the effects of ITE-AHR,we analyzed relationship found the common gene set among literature reported genes that are either migration-related,or regulated by AHR,and between the public data and migration-related genes that were potentially regulated by AHR;then compared them with the gene expression changes collected by RNA-seq after ITE treatment.Several genes were selected from the intersection of the two gene sets for further study.MYH9 is a component of non-muscle myosin IIA(NMIIA),which has been confirmed to be reduced by ITE treatment.When MYH9 was overexpressed in the glioma cells,a good correlation was observed between the expression level and the cell migration ability,which was determined by wound healing assay.Correspondingly,the overexpression of MYH9 eliminated the migration inhibitory effect of ITE,indicating that ITE-AHR inhibited cell migration via inhibiting expression of MYH9.MYH9 is essential for cell migration in 3D confined space,and not a discovered target of AHR,the fact that ITE affects MYH9 via AHR opens a new way of research and development.Glioblastoma is a “cold” tumor lacking T cell infiltration,in which kyurenine,generated by IDO/TDO,functions as an immune suppressor by binding to aryl hydrocarbon receptor(AHR).Hence AHR antagonists have been developed and some shown to activate immune response in IDO over-expressing cancer models.Paradoxically,AHR has been reported to block glioma cell invasion like a tumor suppressor,and how to target AHR in cancer remains an open question.Here we reported that ITE synergized with PD1 antibody to activate immunity by reducing myeloid derived suppressive cells(MDSC)infiltration.Moreover,ITE combined with PD1 antibody significantly increased percentage of CD3+CD8+ and CD3+CD4+ T cells in the glioma tissue.Gene expression profiles of immune regulated genes revealed that a known MDSC inducer,L11,was significantly down-regulated,which was confirmed at protein level in the ITE combined PD1 group.Furthermore,ITE alone suppressed IL11 expression in cultured GL261 cells,and inhibited IL11’s induction of MDSC from the mouse PBMC cells in vitro.Accordingly,stat3,the transcription factor activated by IL11,was inhibited in ITE group.The observed IL11-STAT3 inhibition shed light on ITE’s immune-activating mechanism in this orthotopic mouse glioma model. |
