Wang W, Marsh S, Cassidy J, McLeod H L
Department of Medicine and Therapeutics, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom.
Cancer Res. 2001 Jul 15;61(14):5505-10.
Chemoresistance is a major obstacle for successful cancer treatment. Gene amplification and altered expression are the main genetic mechanisms of tumor chemoresistance. Previously, only a limited number of genes were analyzed in each individual study using traditional molecular methods such as Northern and Southern blotting. In this study, the global gene expression patterns of 1176 genes in a panel of five thymidylate synthase (TS) inhibitor [raltitrexed (TDX) and 5-fluorouracil (5-FU)] resistant and sensitive parent cell lines were investigated using cDNA array technology. Only 28 of 1176 genes were altered >1.5-fold among resistant cells, with 2 genes (TS and YES1) consistently higher in the panel. TS mRNA and protein were consistently overexpressed in all drug-resistant tumor cell lines compared with the sensitive parent cell lines. Southern blot and FISH analysis demonstrated that the TS gene was amplified in 5-FU- and TDX-resistant cell lines. YES1 mRNA and protein were overexpressed in four drug-resistant tumor cell lines but were not overexpressed in the lymphoblast cell line W1L2(TDX), although the YES1 gene was highly amplified in these cells. The fact that W1L2 has high level (>10-fold) resistance to TS inhibitor in the absence of high YES1 expression leads to a conclusion that YES1 has no direct role in this drug resistance process. By narrowing the search from 1176 to 2 genes, the analysis of in vitro TDX and 5-FU resistance becomes more straightforward for confirmatory studies. These data provide encouragement that comprehensive transcript analysis will aid the quest for more enlightened therapeutics.
化疗耐药是癌症成功治疗的主要障碍。基因扩增和表达改变是肿瘤化疗耐药的主要遗传机制。以前，在每项单独研究中，使用诸如Northern和Southern印迹等传统分子方法仅分析了有限数量的基因。在本研究中，使用cDNA阵列技术研究了一组五个胸苷酸合成酶（TS）抑制剂[雷替曲塞（TDX）和5-氟尿嘧啶（5-FU）]耐药和敏感亲本细胞系中1176个基因的全局基因表达模式。在耐药细胞中，1176个基因中只有28个基因的变化>1.5倍，其中2个基因（TS和YES1）在该组中始终较高。与敏感亲本细胞系相比，TS mRNA和蛋白在所有耐药肿瘤细胞系中均持续过表达。Southern印迹和FISH分析表明，TS基因在5-FU和TDX耐药细胞系中扩增。YES1 mRNA和蛋白在四个耐药肿瘤细胞系中过表达，但在淋巴母细胞系W1L2(TDX)中未过表达，尽管YES1基因在这些细胞中高度扩增。W1L2在没有高YES1表达的情况下对TS抑制剂具有高水平（>10倍）耐药性这一事实得出结论，YES1在该耐药过程中没有直接作用。通过将搜索范围从1176个基因缩小到2个基因，体外TDX和5-FU耐药性分析对于验证性研究变得更加直接。这些数据为全面转录分析将有助于寻求更明智的治疗方法提供了鼓励。
