Distinct gene expression signatures during development of distant metastasis

摘要

Using cDNA microarrays, we have conducted a systematic characterization of global gene expression in v-raf or v-raf/v-myc transformed rat liver epithelial (RLE) cell lines exhibiting both non-metastatic and metastatic phenotypes. Seven transformed cell lines were compared with the non-transformed parental RLE cell. The hierarchical clustering analysis of gene expression profiles revealed two groups reflecting the in vivo metastatic potential of the cells. Surprisingly, one non-metastatic cell line Tlwas co-clustered with metastatic cell lines, suggesting that Tl underwent significant genetic changes. The Tl cell line was further compared against all the metastatic cell lines in order to reveal the critical genes required for metastatic conversion but not expressed in the Tl. These data demonstrated that expression of genes involved in apoptosis and immune cell homing were altered in all metastatic cell lines. Survival of both intravasated cells in circulation systems and extravasated cells in a new tissueenvironment might be critical for the final step in the metastatic process. Our study provides gene expression signatures consistent with two critical events in the metastatic process, namely, the acquisition of early homing capacity and increased survival potential of the tumor cells.