Department of Chemistry and Biological Science, School of Science and Engineering, Aoyama Gakuin University, Kanagawa 229-8558, Japan.
Cancer Cell Int. 2010 Jan 21;10:2. doi: 10.1186/1475-2867-10-2.
Lung cancers are the most common type of human malignancy and are intractable. Lung cancers are generally classified into four histopathological subtypes: adenocarcinoma (AD), squamous cell carcinoma (SQ), large cell carcinoma (LC), and small cell carcinoma (SC). Molecular biological characterization of these subtypes has been performed mainly using DNA microarrays. In this study, we compared the gene expression profiles of these four subtypes using twelve human lung cancer cell lines and the more reliable quantitative real-time PCR (qPCR).
We selected 100 genes from public DNA microarray data and examined them by DNA microarray analysis in eight test cell lines (A549, ABC-1, EBC-1, LK-2, LU65, LU99, STC 1, RERF-LC-MA) and a normal control lung cell line (MRC-9). From this, we extracted 19 candidate genes. We quantified the expression of the 19 genes and a housekeeping gene, GAPDH, with qPCR, using the same eight cell lines plus four additional validation lung cancer cell lines (RERF-LC-MS, LC-1/sq, 86-2, and MS-1-L). Finally, we characterized the four subtypes of lung cancer cell lines using principal component analysis (PCA) of gene expression profiling for 12 of the 19 genes (AMY2A, CDH1, FOXG1, IGSF3, ISL1, MALL, PLAU, RAB25, S100P, SLCO4A1, STMN1, and TGM2). The combined PCA and gene pathway analyses suggested that these genes were related to cell adhesion, growth, and invasion. S100P in AD cells and CDH1 in AD and SQ cells were identified as candidate markers of these lung cancer subtypes based on their upregulation and the results of PCA analysis. Immunohistochemistry for S100P and RAB25 was closely correlated to gene expression.
These results show that the four subtypes, represented by 12 lung cancer cell lines, were well characterized using qPCR and PCA for the 12 genes examined. Certain genes, in particular S100P and CDH1, may be especially important for distinguishing the different subtypes. Our results confirm that qPCR and PCA analysis provide a useful tool for characterizing cancer cell subtypes, and we discuss the possible clinical applications of this approach.
肺癌是最常见的人类恶性肿瘤之一，且难以治疗。肺癌通常分为四种组织病理学亚型：腺癌（AD）、鳞状细胞癌（SQ）、大细胞癌（LC）和小细胞癌（SC）。这些亚型的分子生物学特征主要使用 DNA 微阵列进行研究。在这项研究中，我们使用十二种人类肺癌细胞系和更可靠的定量实时 PCR（qPCR）比较了这四种亚型的基因表达谱。
我们从公共 DNA 微阵列数据中选择了 100 个基因，并在八个测试细胞系（A549、ABC-1、EBC-1、LK-2、LU65、LU99、STC1 和 RERF-LC-MA）和一个正常对照肺细胞系（MRC-9）中通过 DNA 微阵列分析进行了检查。在此基础上，我们提取了 19 个候选基因。我们使用 qPCR 对这 19 个基因和管家基因 GAPDH 的表达进行了定量分析，使用了相同的八个细胞系和另外四个验证肺癌细胞系（RERF-LC-MS、LC-1/sq、86-2 和 MS-1-L）。最后，我们使用 12 个基因的基因表达谱进行主成分分析（PCA）对 12 种肺癌细胞系的四种亚型进行了特征描述（AMY2A、CDH1、FOXG1、IGSF3、ISL1、MALL、PLAU、RAB25、S100P、SLCO4A1、STMN1 和 TGM2）。PCA 和基因通路分析的结合表明，这些基因与细胞粘附、生长和侵袭有关。AD 细胞中的 S100P 和 AD 和 SQ 细胞中的 CDH1 被确定为这些肺癌亚型的候选标志物，基于它们的上调和 PCA 分析的结果。S100P 和 RAB25 的免疫组织化学与基因表达密切相关。
这些结果表明，使用 qPCR 和 PCA 对 12 个检测基因进行分析，可以很好地描述由 12 种肺癌细胞系代表的四种亚型。某些基因，特别是 S100P 和 CDH1，可能对区分不同亚型尤为重要。我们的结果证实，qPCR 和 PCA 分析为鉴定癌症细胞亚型提供了有用的工具，我们讨论了这种方法的可能临床应用。
