ErbB2受体抑制剂AG825对ErbB2非过表达乳腺癌细胞增殖的作用及意义

目的:探讨在ErbB2非过表达乳腺癌细胞中是否存在NRGs/ErbB2这种配体作用方式的信号通路活化,进而研究神经调节因子(Neuregulins'NRGs)对ErbB2受体信号转导活化和细胞增殖生长的作用.方法:以ErbB2非过表达乳腺癌细胞MDA-MB-231和MCF-7为研究对象,台盼蓝拒染法检测细胞生长曲线;免疫细胞化学法和Western blot法检测细胞中NRG的表达.应用ErbB2受体功能抑制剂AG825处理两株细胞,MTT法检测比较两株细胞的增殖抑制作用,求出AG825作用MDA-MB-231细胞48 h的IC_(50).40 μmol/L AG825处理MDA-MB-231细胞48 h,流式细胞术检测细胞周期和细胞凋亡.结果:与MCF-7细胞比较,MDA-MB-231细胞具有较强的增殖生长能力.NRG在MDA-MB-231细胞内呈显著表达,MCF-7细胞中无NRG的表达.Western blot实验检测MDA-MB-231细胞可见分子量44 kD的NRG抗体阳性反应条带.应用ErbB2受体功能抑制剂AG825后,MDA-MB-231细胞的增殖抑制作用明显,AG825作用MDA-MB-231细胞48 h的IC_(50)为56.59 μmol/L.40μmol/LAG825处理MDA-MB-231细胞48 h后,细胞周期阻滞在G_0G_1期(P<0.05);细胞凋亡增加(P<0.01).结论:ErbB2非过表达乳腺癌细胞MDA-MB-231可能通过NRGs自分泌或旁分泌作用方式使ErbB2受体信号转导处于激活状态,这与其高增殖、低凋亡恶性行为有关.

Effect and significance of ErbB2 kinase inhibitor AG825 on proliferation of non-overexpression ErbB2 breast cancer cell

Objective:To explore whether there was activation of NRGs/ErbB2 ligand signal transduction pathway on non-overexpression ErbB2 breast cancer cell in order to investigate the effect of activation and proliferation of NRGs on ErbB2 receptor signal transduction pathway.Methods:Non-overexpression ErbB2 breast cancer cell MDA-MB-231 and MCF-7 were studied in the study.Growth curves of the two cell lines were obtained by the trypan blue exclusion method.The expressions of neuregnlin were detected by immunocytochemistry and Western blot.MDA-MB-231 cells and MCF-7 cells were treated with ErbB2 kinase inhibitor AG825,The effect of AG825 on the proliferation was investigated by MTT assay to compare the different effects between the two kinds of cells.The intermediate concentration IC_(50) in 48 hours in MDA-MB-231 cells was determined.MDA-MB-231 cells were treated with 40μmol/L AG825 for 48 hours,and the cell cycle and apoptosis were detected by flow cytometry.Results:Compared with MCF-7 cells,MDA-MB-231 cells presented strong growth ability.MDA-MB-231 cells expressed a relatively higher level of neuregulin,and MCF-7 cells did not express neuregnlin.In the Western blot,the positive reaction band was found in 44 kD which coincided with the molecular weight of NRG in MDA-MB-231 cells.When MDA-MB-231 cells and MCF-7 cells were treated with AG825,MDA-MB-231 cells were inhibited more obviously.The intermediate concentration IC_(50) of AG825 in MDA-MB-231 cells was 56.59 μmol/L.After MDA-MB-231 cells were treated with 40μmol/L AG825 for 48 hours,the cell cycle was arrested in G_0/G_1 phase(P<0.05),and the apoptosis rate was increased (P<0.01).Conclusion :Our study indicated in MDA-MB-231 cells neuregulins could activate ErbB2 receptor signal transduetion pathway by autocrine or paracrine action,which has relation to malignancy behavior of the cells with higher proliferation and lower apoptosis.