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背景和目的:研究提示组蛋白乙酰化酶抑制剂曲古抑菌素A能诱导细胞凋亡。本研究拟探讨曲古抑菌素A对人脑肿瘤细胞的杀伤作用和机制。材料和方法:选用两种人脑肿瘤细胞株,一株为p53突变型的人胶质瘤细胞株T98G,另一株为p53野生型的人神经母细胞瘤细胞株SKNSH;采用SRB细胞毒测定方法检测TSA作用后肿瘤细胞的增殖状态,用琼脂糖凝胶DNA电泳和流式细胞仪定性和定量分析肿瘤细胞凋亡情况,应用Western印迹分析TSA作用前后,肿瘤细胞中高度乙酰化的组蛋白H3、H4,内源性p53蛋白、乙酰化p53蛋白、以及细胞周期相关蛋白p21、p27的变化。结果:TSA在纳摩尔级浓度即能有效抑制肿瘤细胞增殖,并引起高度乙酰化的组蛋白分子H3和H4集聚;用320nM的TSA作用肿瘤细胞24小时,即发生显著的肿瘤细胞凋亡;TSA刺激肿瘤细胞48小时内,p21和p27蛋白表达显著增强,其中p21蛋白水平在4小时后时即明显升高,8小时达高峰;p27蛋白水平升高发生在8小时后,而内源性p53蛋白水平和乙酰化的p53蛋白水平未发生变化。结论:TSA在体外能有效抑制对传统化疗耐药的人脑肿瘤细胞生长,其抗肿瘤生长机理可能是通过上调p21和p27蛋白水平实现的,而不受内源性p53基因状态和蛋白改变的影响。
BACKGROUND AND PURPOSE: Studies suggest that histone acetylase inhibitor trichostatin A induces apoptosis. This study was to explore Trichostatin A killing effect on human brain tumor cells and mechanism. MATERIALS AND METHODS: Two human brain tumor cell lines were selected. One was a mutant p53 human glioma cell line T98G and the other was a wild-type p53 human SKH cell line SKNSH. SRB cytotoxicity assay Methods The proliferation of tumor cells was detected by TSA. The apoptosis of tumor cells was analyzed qualitatively and quantitatively by agarose gel electrophoresis and flow cytometry. Western blotting was used to analyze the effect of TSA on the expression of highly acetylated histone H3, H4, endogenous p53 protein, acetylated p53 protein, and cell cycle related protein p21, p27 changes. Results: At nanomolar concentrations, TSA effectively inhibited the proliferation of tumor cells and caused the accumulation of highly acetylated histone H3 and H4. Tumor cells apoptosis was significantly induced by TSA treatment with 320 nM for 24 hours. TSA Within 48 hours, the expression of p21 and p27 protein were significantly increased. The level of p21 protein increased significantly after 4 hours and peaked at 8 hours. The level of p27 protein increased after 8 hours, while the expression of endogenous p53 Protein levels and acetylated p53 protein levels did not change. CONCLUSION: TSA can effectively inhibit the growth of human brain tumor cells resistant to traditional chemotherapy in vitro. The anti-tumor growth mechanism of TSA may be achieved by up-regulating the protein levels of p21 and p27, but not by the changes of endogenous p53 status and protein influences.