Differential gene expression in colon carcinoma cells and tissues detectedwith a cDNA array

Expression of selected genes coding for proteins with defined cellular func tions was analysed in human cell lines derived from normal colonic mucosa, non-mucinous colonic carcinomas and mucinous colonic carcinomas. Altered ex pression of 10 genes in colon carcinoma cells was found by using a cDNA arr ay; 6 of these alterations (60%) were confirmed by Northern blotting or sem i-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Am ong these 6 genes, 3 transcription factors as well as the topoisomerase II cw and the mitosis inhibitor WEEIHu gene were significantly suppressed in t he tumour cell lines. In addition, the gene coding for the cell cycle inhib itor p21 was overexpressed only in cell lines derived from mucinous carcino mas. The significant suppression of the kinase WEEIHu gene in carcinoma cel ls of both phenotypes and the tendency of the mucinous phenotype to overexp ress p21 protein were confirmed in human colon carcinoma tissues. Our data show that the cDNA array method permits a correct identification of changes in gene expression with a relatively high accuracy. The different expressi on of the p21 gene in the non-mucinous and mucinous carcinoma cells support s the hypothesis that these phenotypes may develop along different genetic pathways. The detection of WEEIHu gene suppression in colon carcinoma cells and tissues suggests its potential role in tumourigenesis. (C) 1999 Wiley- Liss, Inc.