Expression data from E0771 mouse mammary tumor cell line and its derivative with high metastatic potential

A distinct type of macrophages helps breast cancer cells to overcome rate-limiting steps in the metastatic process and establish lethal metastatic tumors. Since only a minor population of cancer cells can establish macroscopic metastatic tumors, we hypothesized that this metastatic cancer cell population have higher expression of receptors for macrophage-derived ligands compared to their parental cells. We used microarrays to investigate this hypothesis, and identified that a selected population of mouse mammary tumor cells with high metastatic potential had higher expression of Met, a gene encoding hepatocyte growth factor receptor. To obtain cancer cell subpopulations with high metastatic potential, we injected E0771 mouse mammary tumor cells into the mammary fat pad of syngeneic C57BL/6 mice and retrieved the metastasized cells from the lung. We repeated this in vivo selection and established second-generation populations (named E0771-HML2). Total RNA was extracted from E0771-HML2 and their parental cells (E0771-parental) in culture, and hybridized on Affymetrix GeneChip Mouse Genome 430 2.0 Array.