Treg Cells Promote Glioma Stem Cells Expansion Through TGF?-IL6-STAT3 Signaling

ObjectiveRegulatory T cells(Tregs)contribute to immune suppression in cancer,but little is known about the interaction between Treg and Glioma Stem cells(GSCs)during Glioma progression.Here,we show a molecular mechanism that how Tregs influence the GSCs qualities in vitro and in vivo.We found that Tregs promoted expansion of GSCs through the TGF-? secretion.Mechanistic investigations indicated that TGF-? acted on cancer cells to induced the core stem cell genes CD133?SOX2?NESTIN?MUSASHI1?ALDH1A expression and sphere formation via NF-?B-IL6-STAT3 signaling pathway,resulting in increased cancer stemness.Furthermore,high CD133 and IL6 expression respective was a prognosis marker of glioma patient.Collectively,our work revealed an immune-associated mechanism that Treg enhanced the GSCs characteristics through TGF-?-NF-?B-IL6-STAT3 signaling pathway and IL6 negatively affects patient outcome.Efforts to target this network might be a strategy in treating glioma patients.MethodsThe Glioma patients were hospitalized during the period January 2013 to 2016 in the First Affiliated Hospital of Zhengzhou University.Paired cancerous tissue and adjacent tissues from 86 cases of glioma patients were collected.Then we used the real time PCR to examine the mRNA expression level of CD133 /IL-6.The protein expression of CD133 in cancerous tissue and adjacent tissues were confirmed by IHC.We obtained the peripheral blood mononuclear cells using the Ficoll-Plaque,Tregs were sorted by magnetic beads.The sorted Tregs were coculture with U251/U87 cells in the Transwell plates.Flow cytometry/RT-PCR/sphere formation assay were used to examine the stemness.RT-PCR and Immunofluorescence were used to confirm that TGF was producted by Tregs.Then we used Western-Blot to examine the protein level of p-NF-?B?p-STAT3?CD133?SOX2?Musashi1?Nestin.Results1.The mRNA expression level of CD133 was higher in tumor tissues than adjacent samples of Glioma patients,In addition,Patients with high CD133 expression had worse survival than those with low CD133 expression.2.Tregs promoted the stem gene expression and sphere formation through producing TGF-?.3.TGF-? increased the IL-6 secretion in tumor cell through the ?F-?B signaling;While the IL-6 disruption significantly inhibited TGF-? mediated promotion of GSC expansion.In addition,patients with low IL-6 expression had greater survival than those with high IL6 expression.4.IL-6 autocrine in tumor cell could promote the Glioma cell stemness by activating STAT3 signaling.ConclusionIn Glioma tumor microenvironment,Tregs could secreted TGF-?,TGF-? increased the IL-6 secretion in tumor cell through the ?F-?B signaling,IL-6 autocrine in tumor cell could promote the glioma cell stemness by activating STAT3 signaling.TGF-? and IL-6 can be used as a potential target for the treatment of glioma,providing a solid theoretical basis for the clinical treatment of glioma.