凋亡抵抗在人肺腺癌SPC-A1/多西紫杉醇细胞系耐药机制中的作用

Role of apoptosis inhibition in the multidrug resistance of the human lung adenocarcinoma cell line SPC-A1/Docetaxel

目的:比较人肺腺癌细胞SPC-A1与耐多西紫杉醇细胞系SPC-A1/多西紫杉醇(Docetaxel)经多西紫杉醇诱导后凋亡的差异,研究抗凋亡机制在肺腺癌多西紫杉醇耐药中的作用。方法:以AnnexinV/PI双染法检测SPC-A1/Docetaxel细胞与SPC-A1细胞经不同浓度多西紫杉醇诱导后的凋亡率,免疫组化法及RT-PCR法分别检测SPC-A1/Docetaxel细胞与SPC-A1细胞bcl-2、bax在蛋白和mRNA水平的表达。结果:SPC-A1/Docetaxel细胞与SPC-A1细胞的自然凋亡率分别为(7.5±1.1)%和(4.7±0.7)%;经5、10和20μg/L的多西紫杉醇作用48 h后,SPC-A1/Docetaxel细胞的凋亡率分别为(7.8±2.1)%、(11.3±3.1)%和(25.6±4.5)%,SPC-A1细胞的凋亡率分别为(23.7±4.5)%、(44.2±5.0)%和(40.9±2.8)%;各组SPC-A1/Docetaxel细胞的早期凋亡率均显著低于SPC-A1细胞(P<0.05)。免疫组化结果显示,SPC-A1/Docetaxel细胞中bcl-2蛋白表达较SPC-A1细胞明显升高(P<0.05),而bax蛋白表达明显降低(P<0.05)。RT-PCR结果显示,与SPC-A1细胞相比,SPC-A1/Docetaxel细胞的bcl-2 mRNA表达升高(P<0.05),而bax mRNA表达降低(P<0.05)。结论:抗凋亡是肺腺癌SPC-A1/Docetaxel细胞多药耐药的机制之一,且与抗凋亡因子bcl-2表达上调和促凋亡因子bax表达下调相关。

Objective： To investigate the role of apoptosis inhibition in the multidrug resistance of the human lung adenoeareinoma cell line SPC-A1/Doeetaxel by comparing the rates of doeetaxel-indueed apoptosis and different expressions of bcl-2 and bax in the docetaxel-resistant cell line SPC-A1/Docetaxel and its parent cell line SPC-A1. Methods ： The apoptosis rates of the two cell lines induced by different concentrations of docetaxel were analyzed by AnnexinV/PI double-labeled flow eytometry. The expression levels of bel-2 and bax protein were detected by immunohistoehemieal staining, and their mRNA expres- sions analyzed by reverse transcription polymerase chain reaction （RT-PCR）. Results： The spontaneous apoptosis rates of the SPC-A1/Doeetaxel cells and SPC-A1 cells were （7.5 ±1.1 ）% and （4. 7 ±0.7）% respectively. The early apoptosis rates induced by 5 pge/L, 10 μg/L and 20 μg/L doeetaxel were （7.8± 2.1 ） %,（ 11.3 ±3.1 ） % and （25.6 ±4.5） % in the SPC-A1/Docetaxel cells, significantly lower than in the SPC-A1 cells, which were （23.7±4.5 ） %, （44.2± 5.0） % and （40.9 ± 2. 8） % respectively （ P 〈 0.05 ）. A statistically higher expression of bcl-2 and lower expression of bax were observed in the SPC-A1/Docetaxel than in the SPC-A1 cells at both mRNA and protein levels （P 〈0.05）. Conclusion： Apoptosis inhibition is one of the mechanisms underlying the multidrug resistance of the human lung adenocarcinoma cell line SPC- A1/Docetaxel and is related with the up-regulation of bcl-2 and down-regulation of bax.