Gene expression analysis in colorectal cancer using practical DNA array filter

PURPOSE: We examined the usability of a newly developed, compact-sized DNA array filter fur studying the gene expression pattern of individual colorec tal cancer. METHODS: Complementary DNA probes were prepared from mRNA extra cted from colonic cancer specimens and adjacent normal mucosa and then were labeled with chemiluminescence. These: Labeled probes were allowed to bind to the gene fragments on the filter. A specialized scanning charge-coupled device camera measured the intensity of each chemiluminescent spot, which is an indicator of the degree to which a specific gene is expressed. Gene e xpression image was quantified into intensity of signals by using computer software. RESULTS: Characteristic gene expression patterns were obtained fr om the colonic cancer cell line, RPMI4788, and the leukemia cell line, HL60 , by using this compact-sized DNA array filter in the preliminary experimen t. Up-regulation of nm23, TIMP1, VEGF, and cyclin E and down-regulation of some tumor suppressor genes (p53, TOSO, and SIVA), beta -catenin, and metal lothionein were observed in colonic cancer specimen when compared with thos e of normal mucosa. CONCLUSIONS: We have obtained unique gene expression pa tterns from colorectal cancer and normal tissue by using a newly developed compact-sized DNA array filter system. Collecting, storing, and analyzing o f gene expression data from many samples of colorectal cancer will enable u s to identify distinct subsets of patients based on molecular characteristi cs in the near future.