鞘氨醇激酶1参与依托泊苷抑制人乳腺癌MDA-MB-231细胞增殖、迁移的研究

目的利用抑制乳腺癌MDA-MB-231细胞中SK-1基因表达，结合依托泊苷对细胞增殖的影响，研究乳腺癌的治疗新方法。方法将依托泊苷分别处理野生型及SK-1敲除型MDA-MB-231细胞，^3H-TdR掺入法分析细胞增殖，Transwell法分析细胞迁移，Western印迹检测SK-1蛋白表达及细胞周期检验点相关信号因子的蛋白表达，RT-PCR检测细胞内SK-1的mRNA表达量。结果依托泊苷在较高剂量时，MDA-MB-231细胞存活率明显下降，但依托泊苷却呈浓度依赖性促进乳腺癌细胞SK-1 mRNA及蛋白水平表达，将SK-1敲除，细胞迁移率下降，而且可以增强G1期各抑癌基因的激活或高表达，使细胞周期阻滞。结论SK-1基因敲除有效增强肿瘤细胞对化疗药物的敏感性。

Regulative Effects of Sphingosine Kinase I and Etoposide on Proliferation and Migration of MDA-MB-231 Human Breast Cancer Cells

Objective This study was aimed to explore novel therapeutics for breast cancer, by combining knockout of sphingosine kinase 1（SK-1） with inhibitory effect of etoposide on cell prolif- eration of human breast cancer cell line MDA-MB-231. Methods Cell proliferation ability was measured by 3H-TdR and the cell migration was performed by Transwell. Western blot assay was used to detect expression of SK-1 and related signal factors at cell-cycle checkpoints, and RT-PCR was performed to observe the levels of SK-1 mRNA. Results Etoposide inhibited cell proliferation of human breast cancer cell MDA-MB-231 at a relatively high dose, but upregulated the expression and mRNA of SK-1 in a dose-dependent manner. SK-1 knockout, in combination with etopside, inhibited migration of MDA-MB-231 cells, and markedly increased expression of signal genes related to G1 arrest of cell-cycle checkpoint. Conclusion Knockout of SK-1 can enhance the sensitivity of human breast cancer cells to chemotherapeutics.