Mendes Kanchana Natarajan, Nicorici Daniel, Cogdell David, Tabus Ioan, Yli-Harja Olli, Guerra Rudy, Hamilton Stanley R, Zhang Wei
Department of Pathology, the University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
J Proteome Res. 2007 Jul;6(7):2753-67. doi: 10.1021/pr070184h. Epub 2007 Jun 12.
Multiple signal transduction pathways play a crucial role in cancer development, progression, and response to different therapies. An important issue is whether common signal transduction pathways are ubiquitously altered in all cancer types and some unique pathways are involved in different cancer types. Another important issue is whether and how transduction signaling molecules are heterogeneously expressed and activated in different cancer cells within and between cancer cell types.
To gain insight into these issues, we assembled a protein lysate array with 90 different cell lines of 12 different cell types. Each sample is diluted 2-fold six times, and samples from the dilution series were printed three times on the array. We then measured the expression levels and phosphorylation status of 52 different signaling proteins with specific antibodies and carried out statistical hierarchical clustering analysis.
The most significant finding based on the cluster analysis was that the cell lines did not group based on tumor types, suggesting that the signaling pathways studied were commonly activated in most of the tumor types cultured in vitro. As expected, related proteins associated with specific signaling pathways clustered together, and analysis of the 30 most differentially expressed proteins revealed the PI3-K signaling pathway was upregulated in several different tumor types and the VEGF-angiogenesis pathway was downregulated in hematopoetic cancers. Another important observation, with clinical implications was that EGFR was the most heterogeneous among all the cell lines. We also observed signaling pathways unique to specific types of cancers such as the inverse relationship between p16ink and Rb, and the EGFR mediated pathway activation characteristic of pancreatic cancers.
Using reverse phase lysate array analysis in this study, we were able to determine potential relationships and signaling pathways, both common and unique, to different types of cancer using cell lines in vitro. This data could be utilized for mining information related to an individual cancer of interest and combined with morphological and genomic profiles would help in creating a combination of expression markers and/or functional signaling maps for specific cancer diagnosis and therapy.
多种信号转导途径在癌症的发生、发展以及对不同治疗的反应中起着至关重要的作用。一个重要问题是，常见的信号转导途径是否在所有癌症类型中普遍改变，以及某些独特的途径是否参与不同的癌症类型。另一个重要问题是，转导信号分子在不同癌细胞类型内和之间是否以及如何异质性表达和激活。
为深入了解这些问题，我们用12种不同细胞类型的90种不同细胞系组装了一个蛋白质裂解物阵列。每个样品进行6次2倍稀释，稀释系列的样品在阵列上打印3次。然后我们用特异性抗体测量52种不同信号蛋白的表达水平和磷酸化状态，并进行统计层次聚类分析。
基于聚类分析的最显著发现是，细胞系并非根据肿瘤类型分组，这表明所研究的信号通路在体外培养的大多数肿瘤类型中普遍被激活。正如预期的那样，与特定信号通路相关的相关蛋白聚集在一起，对30种差异表达最显著的蛋白进行分析发现，PI3-K信号通路在几种不同肿瘤类型中上调，而VEGF-血管生成通路在造血系统癌症中下调。另一个具有临床意义的重要观察结果是，EGFR在所有细胞系中是最具异质性的。我们还观察到特定癌症类型特有的信号通路，如p16ink与Rb之间的反向关系，以及胰腺癌特有的EGFR介导的通路激活。
在本研究中使用反相裂解物阵列分析，我们能够利用体外细胞系确定不同类型癌症常见和独特的潜在关系及信号通路。这些数据可用于挖掘与感兴趣的个体癌症相关的信息，与形态学和基因组图谱相结合将有助于创建特定癌症诊断和治疗的表达标志物组合和/或功能信号图谱。
