Influence of p53-upregulated modulator of apoptosis on the growth of glioma cells with different p53 phenotypes / 肿瘤研究与临床

ABSTRACT

Objective To observe the influence of p53-upregulated modulator of apoptosis (PUMA) on the growth of human brain glioma cell lines U251 (p53 mutant) and SHG-44 (p53 wild type),and to explore its possible mechanism.Methods Construct the adenovirus PUMA (Ad-PUMA) and vector of adenovirus (AdDsRed) which were respectively transfected into glioma cell lines U251 and SHG-44.Cells proliferation rates were measured with cell counting kit-8 (CCK-8).The apoptotic ratios were detected by flow cytometry.The expression of PUMA and apoptosis associated proteins (bcl-2,Bax) were determined with Western blot analysis.Caspase-3,Caspase-8,Caspase-9 activity were measured by Caspase activity assay kit.Results Compared with vector group and blank control group,Ad-PUMA transfected group showed strong cell proliferating inhibition effects [the inhibition rates were (50.89±4.73) ％ and (44.45±5.33) ％ respectively,P ＜0.05] and pro-apoptotic effects [apoptotic rates were (44.89±5.08) ％ and (31.67±7.32) ％,P ＜ 0.05] in different p53 glioma cell lines U251 and SHG-44.Western blot analysis showed that PUMA protein expression increased after Ad-PUMA transfection,accompanied by the reduced expression of the anti-apoptotic protein bcl-2 and the increased expression of pro-apoptotic protein Bax.The activity of Caspase testing results showed that the Caspase-3,Caspase-9 activity increased significantly,while the Caspase-8 activity changed little.Conclusion No matter how p53 phenotype,PUMA can inhibit glioma proliferation,promote apoptosis,and its mechanism may be through the mitochondrial apoptotic pathways,upregulation of Bax and inhibition of bcl-2 expression,which activated Caspase-9.Ad-PUMA is expected to become a new target for gene therapy of gliomas.