Identification of novel metastases-suppressor genes involved in breast cancer brain metastases (BCBM) formation

Initial screening for potential metastases suppressors down regulated by methylation was performed using breast cancer cell line models specific for site-specific metastasation. Gene expression profiling and qRT-PCR validations were conducted on tumor tissues from primary breast cancer (BC) and BCBM. CADM1 and RECK were further characterized for their methylation patterns and finally the protein expression of CADM1 was validated in a large number of BC and BCBM samples and correlated with clinico-pathologic parameters. A subclone of MDA-MB-231, which has a high metastatic potential for the brain (MDA-MB-231 BR), was compared to the parental MDA-MB-231 WT and to a bone-seeking subclone (MDA-MB-231 SA) in order to find genes, which might be specifically involved in brain metastasis formation. The cell lines were treated with 5-Aza-2'-deoxycytidine in order to find genes potentially down regulated by methylation. The non-tumorigenic epithelial cell line MCF 10A was used to control for stress response after the treatment with 5-Aza-2'-deoxycytidine.