Gene expression profiles of spontaneous metastasis in a K-ras/p53 mutant mouse model

The biologic basis for NSCLC metastasis is not well understood. Here we addressed this deficiency by transcriptionally profiling tumors from a genetic mouse model of human lung adenocarcinoma that develops metastatic disease owing to the expression of K-rasG12D and p53R172H. We identified 2,209 genes that were differentially expressed in distant metastases relative to matched lung tumors. Mining of publicly available data bases revealed this expression signature in a subset of NSCLC patients who had a poorer prognosis than those without the signature. Primary lung adenocarcinomas and metastases from p53R172H∆g/+ K-rasLA1/+ mice or syngeneic tumors were isolated, carefully dissected to remove the adjacent tissue, snap-frozen in liquid nitrogen and stored at -80° until use. Part of each dissected tumor was histologically evaluated by a board-certified pathologist. Synthesis of cRNA and hybridization to Mouse Expression Array 430A 2.0 chips were performed. Two-sided t-paired tests using log-transformed expression values determined significant differences between primary tumors and metastasis.

非小细胞肺癌（NSCLC）转移的生物学基础尚未完全阐明。为此，我们针对该研究空白，对一株因表达K-rasG12D与p53R172H突变而发生转移性病变的人肺腺癌遗传小鼠模型的肿瘤组织开展转录组表达谱分析。我们鉴定出2209个在远端转移灶中相较于配对原发肺肿瘤存在差异表达的基因。对公开数据库的挖掘显示，该表达特征可在一类非小细胞肺癌患者亚组中被检测到，此类患者的预后较未携带该特征的患者更差。我们从p53R172HΔg/+ K-rasLA1/+小鼠或同基因移植瘤中分离原发肺腺癌组织与转移灶，经精细解剖去除毗邻组织后，于液氮中快速冷冻，并保存于-80℃直至实验使用。每份解剖后的肿瘤组织均由获得委员会认证的病理学家进行组织学评估。本研究完成了互补RNA（cRNA）的合成，并将其与小鼠表达芯片430A 2.0（Mouse Expression Array 430A 2.0）进行杂交。采用对数转换后的表达值进行双侧配对t检验，确定了原发肿瘤与转移灶之间的显著表达差异。