pEGFPN1-dnEGFR对胃癌细胞的化疗增敏作用

Effects of pEGFPN1-dnEGFR on Chemosensitivity to Oxaliplatin of Gastric Carcinoma Cells

目的研究人EGFR显性负性突变体真核表达载体(pEGFPN1-dnEGFR)对人胃癌细胞株SGC-7901和NCI-N87化疗敏感性的影响,并探讨其可能机制。方法 MTT法测定奥沙利铂对稳定转染pEGFPN1-dnEGFR和pEGFP-N1载体的两种胃癌细胞的量效反应。奥沙利铂作用各组细胞24 h后,RT-PCR检测各组细胞中Caspase-3和Cyclin D1的mRNA表达情况;Western blot检测各组细胞中Caspase-3和Cyclin D1蛋白表达情况。结果转染pEGFPN1-dnEGFR后,两种胃癌细胞对奥沙利铂的敏感性增加,奥沙利铂对pEGFPN1-dnEGFR转染组细胞的增殖抑制率(VI)与对照组相比有显著提高(P<0.05)。RT-PCR显示pEGFPN1-dnEGFR转染组细胞Cyclin D1 mRNA表达较对照组下降,而Caspase-3 mRNA表达较对照组升高(P<0.05);Western blot显示pEGFPN1-dnEGFR转染组细胞Cyclin D1蛋白表达较对照组下降,而Caspase-3蛋白表达较对照组升高(P<0.05)。结论 EGFR显性负性突变体能提高胃癌细胞对化疗药物奥沙利铂的敏感性,其机制可能与Caspase-3和Cyclin D1有关。

Objectives To investigate the effects of pEGFPNI-dnEGFR on Chemosensitivity of human gastric carcinoma cell lines SGC-7901 and NCI-N87 to oxaliplatin, and to elucidate the potential mechanism. Methods Oxaliplatin in different concentrations were added to each group, the dose-effect response was examined by MTT assay. The mRNA expression of Caspase-3 and Cyclin D1 were detected by reverse transcription PCR （RT-PCR） in each group at 24 h after incubated with oxaliplatin. Protein expression of Caspase-3 and Cyclin D1 were detected by Western blot. Results pEGFPNI-dnEGFR could increase the sensitivity to oxaliplatin in both two human gastric carcinoma cell lines. The value of inhibition （VI） of oxaliplatin in groups added with pEGFPNI-dnEGFR and oxaliplatin were significantly higher than those in other groups （P 〈0. 05 ）. RT-PCR results showed that mRNA expression of Cyclin D1 was decreased in cells tranfected with pEGFPN1- dnEGFR （P 〈 0.05 ）. In contrast, Caspase-3 mRNA was increased in ceils incubated with oxaliplatin for 24 h. Western blot results showed that tranfection with pEGFPN1-dnEGFR lead to a decrease of Cyclin D1 protein expression, and an increase of Caspase-3 protein expression after 48 h incubated with oxaliplatin （ P 〈0.05 ）. Conclusion pEGFPN1 -dnEGFR can enhance the chemosensitivity to oxaliplatin in human gastric carcinoma cells,which may be associated with Caspase-3 and Cyclin D1.