Differential display analysis of breast carcinoma cells enriched by immunomagnetic target cell selection: Gene expression profiles in bone marrow target cells

The red bone marrow (BM) is an important indicator organ of hematogenous mi crometastatic spread of carcinomas. Characterization of biological properti es specific for BM micrometastatic cells, however, is technically challengi ng due to the limited number of target cells usually available for the purp ose. This report provides referrals to qualitative gene expression profilin g of BM micrometastatic cells enriched by immunomagnetic selection. First, an experimental strategy was used to study regulatory mechanisms involved w hen BM micrometastatic cells colonize distant organs. The MA-II cells, orig inating from BM micrometastases in a breast cancer patient clinically devoi d of overt metastatic disease, were injected into immunodeficient rats. Met astatic MA-II cells were subsequently immunoselected from the resulting in vivo lesions. The selected cell populations were compared to the injected c ells by differential display analysis, and several genes possibly involved in tumor cell invasion and proliferation were confirmed as differentially e xpressed among the various MA-II cell populations, A direct approach to qua litative gene expression profiling of BM micrometastatic cells was also exp lored. Carcinoma cells were immunoselected from BM and axillary lymph nodes obtained from breast cancer patients, and the isolated cell populations we re compared by differential display analysis. Two candidate genes, identifi ed as factors involved in cellular growth control, appeared as differential ly expressed by the target cells from BM. Our study provides detailed infor mation on how to combine an immunomagnetic selection procedure and differen tial display analysis to reveal gene expression profiles that may character ize BM micrometastatic cells. (C) 2002 Wiley-Liss, Inc.