Study On The Mechanism Of G9a Inhibitor BIX-01294on Glioma U251Cell Lines

[Objective]: To study the expressions of histone methyltransferase G9a, histone H3K9me2and H3K9me in human glioma tissues and research its clinical significances. We also studied the effect of histone methylase G9a inhibitor BIX-01294on cell biology, histone methylation and acetylation in human glioma U251cells in vitro.[Method]:1. The expressions of histone methyltransferase G9a, histone H3K9me2and H3K9me1in human glioma tissues and para-carcinoma tissue were detected by immunohistochemical method. Its clinical significance was explored by statistical analysis.2. The cell growth inhibition of human glioma U251cells after BIX-01294treatment was measured by MTS method. TUNEL was used for analysis of the cell apoptosis.3. Apoptosis-related proteins BCL-2, Bax, Caspase-9and Caspase-3, and histone H3K9me1, H3K9me2, H3K9me3, H3K27me1, H3K27me2and histone H3were detected by western blot.[Results]:1. The positive rate of histone methyltransferase G9a in the glioma cancer tissue was86%(43/50) and42%(21/50) in the para-carcinoma tissue, p<0.01. The positive rate of histone H3K9me2was82%(41/50) in cancer tissue and38%(19/50) in the para-carcinoma tissue, χ2=18.38, p<0.01; The expressions of histone methyltransferase G9a and histone H3K9me2was associated with the WHO classification of glioma; The positive rate of histone H3K9me1was54%(27/50) in the glioma cancer tissue, and44%(22/50) in the para-carcinoma tissue, χ2=1.21, P>0.05.2. BIX-01294inhibited the proliferation of human glioma U251cells, down-regulated the expression of anti-apoptosis protein BCL-2, up-regulated the expression of pro-apoptotic protein Bax, activated the apoptosis promoter protein caspase-9and effective protein caspase-3, and induced cell apoptosis.3. BIX-01294down-regulated the expression levels of histone H3K9me, H3K9me2, H3K27me and H3K27me2, but there was no effect on the acetylation of histone H3K9me3and histone H3.[Conclusion]:1. The expressions of histone methyltransferase G9a and H3K9me2in the cancer tissue of glioma are higher than that in para-carcinoma tissue, and they correlate to the WHO classification of gliomas, indicating that G9a and H3K9me2might play a role in pathogenesis in glioma.2. BIX-01294could inhibit the proliferation of glioma cells. It triggers the apoptotic process, and induces the tumor cell apoptosis. Further study show that BIX-01294downregulate histones H3K9and H3K27. BIX-01294might be a potential new drug for treatment of glioma.