Hegde Priti S, Rusnak David, Bertiaux Melissa, Alligood Krystal, Strum Jay, Gagnon Robert, Gilmer Tona M
Department of Genomic and Proteomic Sciences, GlaxoSmithKline, Inc., Research Triangle Park, North Carolina 27709, USA.
Mol Cancer Ther. 2007 May;6(5):1629-40. doi: 10.1158/1535-7163.MCT-05-0399.
Lapatinib (GW572016) is a small-molecule dual inhibitor of epidermal growth factor receptor (ErbB1) and ErbB2 receptor kinase activities currently in phase III clinical trials. We used phosphoprotein and microarray analyses to carry out targeted pathway studies of phosphorylation and gene expression changes in human breast cancer cell lines in the presence or absence of lapatinib. Studies were done in four breast cancer cell lines, two of which were responsive and two of which were nonresponsive to lapatinib. Responsive cell lines, BT474 and SKBr3, constitutively overexpress ErbB2 and show an IC(50) of 25 or 32 nmol/L for lapatinib, respectively. In contrast, nonresponsive MDA-MB-468 and T47D cells expressed a low basal level of ErbB2 and showed IC(50) values in the micromolar range. Cells responsive to lapatinib exhibited strong differential effects on multiple genes in the AKT pathway. After 12 h of exposure to 1.0 micromol/L of lapatinib, AKT1, MAPK9, HSPCA, IRAK1, and CCND1 transcripts were down-regulated 7- to 25-fold in responsive BT474 and SKBr3 cells. In contrast, lapatinib weakly down-regulated the AKT pathway in nonresponsive breast cancer cell lines (<5-fold down-regulation of most genes in the pathway). Furthermore, the proapoptotic gene FOXO3A, which is negatively regulated by AKT, was up-regulated 7- and 25-fold in lapatinib-responsive SKBr3 and BT474 cells, respectively. Phosphorylated Akt and Akt-mediated phosphorylation of FOXO3A also decreased in responsive breast cancer cell lines exposed to lapatinib. Gene expression profiling also revealed that lapatinib stimulated the expression of estrogen and progesterone receptors and modulated the expression of genes involved in cell cycle control, glycolysis, and fatty acid metabolism. In BT474 and T47D cells, which expressed moderate basal levels of the estrogen and progesterone receptors, 1.0 micromol/L of lapatinib induced expression by 7- to 11-fold. These data provide insight into the mechanism of action of lapatinib in breast cancer cells.
拉帕替尼（GW572016）是一种小分子双抑制剂，可抑制表皮生长因子受体（ErbB1）和ErbB2受体激酶活性，目前正处于III期临床试验阶段。我们使用磷酸化蛋白和微阵列分析，对存在或不存在拉帕替尼的情况下人乳腺癌细胞系中磷酸化和基因表达变化进行靶向通路研究。研究在四种乳腺癌细胞系中进行，其中两种对拉帕替尼有反应，两种对拉帕替尼无反应。有反应的细胞系BT474和SKBr3组成性过表达ErbB2，对拉帕替尼的IC（50）分别为25或32 nmol/L。相比之下，无反应的MDA-MB-468和T47D细胞表达的ErbB2基础水平较低，IC（50）值在微摩尔范围内。对拉帕替尼有反应的细胞对AKT通路中的多个基因表现出强烈的差异效应。在暴露于1.0 μmol/L拉帕替尼12小时后，有反应的BT474和SKBr3细胞中AKT1、MAPK9、HSPCA、IRAK1和CCND1转录本下调7至25倍。相比之下，拉帕替尼在无反应的乳腺癌细胞系中对AKT通路的下调作用较弱（该通路中大多数基因下调<5倍）。此外，受AKT负调控的促凋亡基因FOXO3A在对拉帕替尼有反应的SKBr3和BT474细胞中分别上调7倍和25倍。在暴露于拉帕替尼的有反应的乳腺癌细胞系中，磷酸化的Akt和Akt介导的FOXO3A磷酸化也降低。基因表达谱分析还显示，拉帕替尼刺激雌激素和孕激素受体的表达，并调节参与细胞周期控制、糖酵解和脂肪酸代谢的基因表达。在表达中等基础水平雌激素和孕激素受体的BT474和T47D细胞中，1.0 μmol/L的拉帕替尼诱导表达增加7至11倍。这些数据为拉帕替尼在乳腺癌细胞中的作用机制提供了见解。
