Chen Xi, Wang Han, Ou-Yang Xue-Nong, Xie Fang-Wei, Wu Jing-Jing
Department of Medical Oncology, Fuzhou General Hospital of Nanjing Military Command, Fuzhou, China.
Contemp Oncol (Pozn). 2013;17(4):363-9. doi: 10.5114/wo.2013.35292. Epub 2013 Oct 7.
To discuss the activation of the signal transduction pathway of phosphatidylinositol 3'-kinase/serine-threonine kinase (PI3K/Akt), one of the important targets of drug resistance of trastuzumab, which provides a theoretical basis for the targeted therapy of drug resistance of trastuzumab in breast cancer.
Establish the drug-resistance sub-strain BT-HerR of trastuzumab for the continuous treatment of human breast cancer cell strain BT474, conduct Her-2 phenotype analysis on the drug-resistance cell strain BT-HerR with the FISH method, detect the proliferation inhibition in vitro of trastuzumab to BT474 and BT-HerR cells with the MTT method, detect the apoptosis variation after interference of trastuzumab with a flow cytometer and detect p-Akt and apoptosis-related protein expression with Western blot after PI3K/Akt inhibitor LY294002 interferes with the cells.
The gene expression of drug-resistance cell strain BT-HerR Her-2 is strongly positive; 72 hours after interference of trastuzumab, the proliferation in vitro of the BT474 and BT-HerR cells is inhibited, which is strengthened with the increase of concentration, showing a significant difference (p < 0.01); after treatment of trastuzumab, comparison of the cell apoptosis rate of BT474 and BT-HerR shows a significant difference (p < 0.01); trastuzumab can only inhibit the Akt protein phosphorylation of BT474, while LY294002 can inhibit the BT-HerR and BT474 Akt protein phosphorylation simultaneously.
Akt protein phosphorylation of trastuzumab drug-resistance cells is activated; LY294002, a PI3K/Akt inhibitor, can obviously inhibit Akt protein phosphorylation of trastuzumab drug-resistance cells and there is a clear association between the PI3K/Akt signal transduction pathway and trastuzumab resistance.
探讨磷脂酰肌醇3'-激酶/丝氨酸-苏氨酸激酶（PI3K/Akt）信号转导通路的激活情况，该通路是曲妥珠单抗耐药的重要靶点之一，为乳腺癌中曲妥珠单抗耐药的靶向治疗提供理论依据。
通过连续传代培养人乳腺癌细胞系BT474建立曲妥珠单抗耐药亚株BT-HerR，采用荧光原位杂交（FISH）法对耐药细胞株BT-HerR进行Her-2表型分析，采用MTT法检测曲妥珠单抗对BT474和BT-HerR细胞的体外增殖抑制作用，用流式细胞仪检测曲妥珠单抗干预后细胞凋亡变化，用蛋白质免疫印迹法检测PI3K/Akt抑制剂LY294002干预细胞后p-Akt及凋亡相关蛋白表达。
耐药细胞株BT-HerR的Her-2基因表达呈强阳性；曲妥珠单抗干预72小时后，BT474和BT-HerR细胞的体外增殖受到抑制，且随浓度增加抑制作用增强，差异有统计学意义（p<0.01）；曲妥珠单抗处理后，BT474和BT-HerR细胞凋亡率比较差异有统计学意义（p<0.01）；曲妥珠单抗仅能抑制BT474的Akt蛋白磷酸化，而LY294002能同时抑制BT-HerR和BT474的Akt蛋白磷酸化。
曲妥珠单抗耐药细胞的Akt蛋白磷酸化被激活；PI3K/Akt抑制剂LY294002能明显抑制曲妥珠单抗耐药细胞的Akt蛋白磷酸化，PI3K/Akt信号转导通路与曲妥珠单抗耐药存在明确关联。
