Screening of the Metastasis-Associated Genes by Gene Chip in High Metastatic Human Ovarian Cancer Cell Lines

Affymetrix U133A oligonucleotide microarrays were used to study the differences of gene expressions between high (H) metastatic ovarian cancer cell line, HO-8910PM, and normal ovarian tissues (C), bioinformatics was used to identify their chromosomal localizations. A total of 1,237 genes were found to have a difference in expression levels more than eight times. Among them 597 were upregulated (Signal Log Ratio[SLR] ≥ 3), and 640 genes were downregulated (SLR≤3). Except one gene, whose location was unknown, all these genes were randomly distributed on all the chromosomes. However, chromosome 1 contained the most differentially expressed genes (115 genes, 9.3%), followed by chromosome 2 (94 genes, 7.6%), chromosome 12 (88 genes, 7.1%), chromosome 11 (76 genes, 6.1%), chromosomes X (71 genes, 5.7%), and chromosomes17 (69 genes, 5.6%). These genes were localized on short-arm of chromosome (q), which had 805 (65.1%) genes, and the short arms of No.13, 14, 15, 21, and 22 chromosomes were the only parts of the chromosomes where the differentially expressed genes were localized. Functional classification showed that most of the genes (306 genes, 24.7%) belonged to the enzymes and their regulator groups. The subsequent group was the nucleic acid binding genes (144 genes, 11.6%). The rest of the top two groups were signal transduction genes (137 genes, 11.1%) and proteins binding genes (116 genes, 9.4%). These comprised 56.8% of all the differentially expressed genes. There were also 207 genes whose functions were unknown (16.7 %). Therefore it was concluded that differentially expressed genes in high metastatic ovarian cancer cell were supposed to be randomly distributed across the genome, but the majority were found on chromosomes 1, 2, 12, 11, 17, and X. Abnormality in four groups of genes, including in enzyme and its regulator, nucleic acid binding, signal transduction and protein binding associated genes, might play important roles in ovarian cancer metastasis. Those genes need to be further studied.