MRTF-a Is Involved In Regulating Glioma Cell Differentiation

Glioblastoma is the most common type brain cancer in the nervous system. Statistical data in China reveal that, in brain tumors, the incidence of glioblastoma is the highest, about40.49%. MRTF-A is a cofactor of serum response factor (SRF), interacts with SRF binding to CarG box, and activates target genes. The researches on molecular mechanism of gliomas differentiation controlled by MRTF-A provide basic for new drug development. Cellular and molecular biology techniques were used to clear the molecular mechanism by which MRTF-A regulated glioma differentiation. The main concept and results are as follow.First, the primary gliacells of neonatal Sprague Dawley (SD) rats were isolated and cultured. Primary gliacells were identified by immunofluorescence and RT-PCR. The results showed that the cells isolated exhibited the positive GFAP expression, and are rat gliacells. To research the levels of MRTF-A and Egr-1in normal glia cells and gliblastoma, mRNA and protein of them were isolated, then RT-PCR and Western blotting were performed to test the mRNA and protein levels of MRTF-A, Egr-1, GFAP and Ki67. The data indicated that compared with normal glia cells, gliblastoma exhibited high expression of Ki67, and low expression of MRTF-A, Egr-1and GFAP.We constructed the luciferase reporter plasmid containing Egr-1promoter, which have live CArG box sites. The luciferase activity analysis in COS-7and C6cells indicated that MRTF-A could significantly activite Egr-1promoter transcription. We overexpressed MRTF-A in gliblastoma, and study effect of MRTF-A on gliblastoma differentiation by immunocytochemistry, RT-PCR and Western blotting. The results demonstrated that MRTF-A could greatly increase the expression of GFAP, and suppress Ki67. The data indicated that MRTF-A could induce gliblastoma differentiation. The expression of Egr-1was upregultated during gliblastoma differentiation induced by MRTF-A. which showed the participation of Egr-1in this process.We study the role of MRTF-A in protecting glia cells from death by the research model. MTT results showed that MRTF-A could enhance glia cell viablity. and this indicated that MRTF-A might protect differentiating glioma cells from death.