HUMAN BREAST-CANCER CELL METASTASIS TO LONG-BONE AND SOFT ORGANS OF NUDE-MICE - A QUANTITATIVE ASSAY

Bone is a common metastatic site in human breast cancer (HBC). Since b one metastasis occurs very rarely from current spontaneous or experime ntal metastasis models of HBC cells in nude mice, an arterial seeding model involving the direct injection of the cells into the left ventri cle has been developed to better understand the mechanisms involved in this process, We present here a sensitive polymerase chain reaction ( PCR) method to detect and quantitate bone and soft organ metastasis in nude mice which have been intracardially inoculated,vith Lac Z transd uced HBC cells. Amplification of genomically incorporated Lac Z sequen ces in MDA-MB-231-BAG HBC cells enables us to specifically detect thes e cells in mouse organs and bones, We have also created a competitive template to use as an internal standard in the PCR reactions, allowing us to better quantitate levels of HBC metastasis, The results of this PCR detection method correlate well,vith cell culture detection from alternate long bones from the same mice, and are more sensitive than g ross Lac Z staining with X-gal or routine histology. Comparable qualit ative results were obtained ,vith PCR and culture in a titration exper iment in which mice were inoculated with increasing numbers of cells, but PCR is more quantifiable, less time consuming, and less expensive. This assay can be employed to study the molecular and cellular aspect s of bone metastasis, and could easily be used in conjunction with RT- PCR-based analyses of gene products which may be involved with HBC met astasis.