Effect of lovastatin on proliferation and apoptosis of glioma stem cells

doi:10.3969/j.issn.2095-4344.2016.32.010

Abstract

Abstract:

BACKGROUND: Increasing evidence has shown that lovastatin with less toxicity to normal cells has crucial effects on proliferation, apoptosis and differentiation of various cancer cells. However, its roles in glioma stem cells remain unclear.
OBJECTIVE: To explore the effect of lovastatin on proliferation and apoptosis of glioma stem cells.
METHODS: Flow cytometric sorting was used to separate glioma stem cells from human glioblastoma cell line U87. Effects of lovastatin on the proliferation and apoptosis of glioma stem cells were determined by MTT and flow cytometry, respectively. Furthermore, expression levels of Ki67, Bax and Bcl-2 in glioma stem cells treated with lovastatin were detected using western blot analysis.
RESULTS AND CONCLUSION: The CD133-positive glioma stem cells were sorted from human glioblastoma cell line U87 with a positive percentage of 85%. MTT assay showed that lovastatin inhibited the proliferation of glioma stem cells in dose (5, 10, 20 μmol/L)- and time (24, 48, 72, 96 hours)-dependent manners. Flow cytometry analysis showed that 10 μmol/L lovastatin (48 hours) induced apoptosis in glioma stem cells. In addition, the expression level of Ki67 was decreased by lovastatin treatment in a dose-dependent manner, and the Bcl-2 and Bax expression levels were reduced and increased by 10 μmol/L lovastatin treatment, respectively. In conclusion, lovastatin can inhibit cell proliferation and induce apoptosis of glioma stem cells, and lovastatin may be a potential drug for treatment of brain tumors.

中国组织工程研究杂志出版内容重点：干细胞；骨髓干细胞；造血干细胞；脂肪干细胞；肿瘤干细胞；胚胎干细胞；脐带脐血干细胞；干细胞诱导；干细胞分化；组织工程

Key words: Lovastatin, Glioma, Neoplastic Stem Cells, Cell Proliferation, Apoptosis, Tissue Engineering

CLC Number:

R394.2

Wen Gong-ling, Wen Chang-ming, Wang Yan-ping, Kang Mei-juan, Zhou Jing, Zhang Bao-chao. Effect of lovastatin on proliferation and apoptosis of glioma stem cells[J]. Chinese Journal of Tissue Engineering Research, 2016, 20(32): 4778-4784.

Figures/Tables 1

2.1 U87胶质瘤干细胞分选结果流式细胞仪分选之前，人类恶性胶质母细胞瘤细胞系U87中CD133阳性细胞比率为0.5%，分选后CD133阳性细胞比率为85%，分选前后差异有非常显著性意义，胶质瘤干细胞纯度较高，可以进行后续实验。 2.2 洛伐他汀对胶质瘤干细胞增殖的影响图1结果显示，不同浓度洛伐他汀(5，10，20 μmol/L)处理胶质瘤干细胞48 h后，各组细胞的增殖率分别为对照组的85%(P < 0.05)、76%(P < 0.05)及56%(P < 0.05)，说明5-20 μmol/L洛伐他汀均能显著抑制胶质瘤干细胞的增殖，且药物浓度越高，细胞的增殖率越低。图2结果显示，10 μmol/L洛伐他汀处理胶质瘤干细胞24，48，72，96 h后细胞的增殖率分别为86%(P < 0.05)、78%(P < 0.05)、65%(P < 0.05)及45%(P < 0.05)，说明随着时间的延长洛伐他汀对胶质瘤干细胞的抑制性越强，细胞的增殖率越低。实验又进一步使用Western blot检测不同浓度洛伐他汀(5，10，20 μmol/L)处理胶质瘤干细胞48 h后Ki67的表达情况，由图3结果可知，随着药物浓度的升高，Ki67的表达量逐渐降低，处理组的蛋白相对表达量分别为对照组的76%(P < 0.05)、53%(P < 0.05)及31%(P < 0.05)，说明5-10 μmol/L洛伐他汀能够剂量依赖性抑制胶质瘤细胞中Ki67的表达。Ki67是细胞增殖的标记性蛋白，Ki67蛋白表达水平的降低，意味着细胞增殖速度的降低，洛伐他汀能够抑制Ki67的表达，进一步验证了其能够抑制胶质瘤干细胞的增殖[20-21]。 2.3 洛伐他汀对胶质瘤干细胞凋亡的影响图4结果显示，对照组即未使用洛伐他汀处理的细胞凋亡率为3.36%，10 μmol/L洛伐他汀处理48 h后，细胞凋亡率为31.62%，与对照组相比差异有非常显著性意义(P < 0.01)。实验进一步检测10 μmol/L洛伐他汀处理胶质瘤干细胞48 h后细胞中凋亡相关蛋白Bax及Bcl-2的表达情况，图5结果显示，10 μmol/L洛伐他汀能够提高Bax的表达(P < 0.05)，同时降低Bcl-2的表达(P < 0.05)。在细胞凋亡过程中，Bax属于促凋亡蛋白，Bcl-2属于抗凋亡蛋白，Bax的增加及Bcl-2的减少说明洛伐他汀促进了胶质瘤干细胞的凋亡，进一步验证了流式细胞仪的检测结果，即洛伐他汀能够诱导胶质瘤干细胞的凋亡[22-25]。"

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