转染XRCC3基因的人脑胶质瘤细胞增加烷化剂类抗癌药耐药性

Xrcc-3 Mediates DNA Crosslinking Agent Drug Resistance in Human Glioma Cells

我们既往的研究表明,在人上皮肿瘤细胞中,XRCC3基因的表达水平同肿瘤细胞对美法仑和顺铂的耐药密切相关,提示XRCC3基因在其中起关键作用。为进一步研究XRCC3基因在脑胶质瘤细胞耐药中的作用,我们选用低水平表达XRCC3基因的人脑胶质瘤细胞SKI-1,将其过度表达XRCC3,研究其耐药性的变化。方法:采用脂质体方法将已插入XRCC3基因的pcDNA3.0表达载体转染人脑胶质瘤细胞SKI-1,G418筛选,得到稳定高表达XRCC3的细胞克隆,转染pcDNA3.1空载体作为对照,用Westem blot方法证实。采用改良的sulforhodamine B(SRB)Colorimetric抗癌药筛选法,对稳定表达XRCC3基因和空载体的SKI-1细胞进行细胞毒试验。结果:XRCC3细胞能稳定地高表达XRCC3蛋白,较MOCK细胞高4倍。XRCC3细胞对顺铂和美法仑的耐药性明显较MOCK细胞增强,分别增加了1.8和2.3倍;对BCNU的耐药性无明显增加。结论:XR-CC3基因在人脑胶质瘤细胞对DNA交链剂耐药中起重要作用。

BACKGROUND & OBJECTIVE: Recent studies have suggested that homologous recombina-tion repair (HRR) as represented by Rad5l foci density and Xrcc-3 levels correlates with DNA cross-linking agent drug resistance. METHODS: In order to confirm that Xrcc3 contributes to DNA cross-link agents resis-tance, in recent investigation, we constructed a pcDNA3.0-XRCC3 plasmid and stably transfected into the hu-man glioma cell line, SKI-1 which has lower XRCC3 expression using the lipsome mediated transfection tech-nique. After C418 selection, a stable transfected cell line was obtained, and was tested with several alkylating agents utilizing a modified sulforhodamine B(SRB) Colorimetric method. RESULTS: XRCC3 was over-ex-pressed in SKI-1 cells (XRCC-3 cells). Compare with MOCK cells, XRCC-3 cells were 2 to 3 fold resistant to DNA cross-linking agents. CONCLUSIONS: These results suggest that XRCC3 is an important factor in DNA cross-linking drug resistance in human gliom cells.