ABSTRACT: Metastasis suppressor genes (MSGs) have contributed to an understanding of regulatory pathways unique to the lethal metastatic process. When re-expressed in experimental models, MSGs block cancer spread to, and colonization of distant sites without affecting primary tumor formation. On a single MSG basis, genes have been identified with expression patterns inverse to a MSG, and found to encode functional, druggable signaling pathways. We now hypothesize that common signaling pathways mediate the effects of many MSGs. By gene expression profiling of human MCF7 breast carcinoma cells expressing a scrambled siRNA or siRNAs to each of 19 validated MSGs (NME1, BRMS1, CD82, CDH1, CDH2, CDH11, CASP8, MAP2K4, MAP2K6, MAP2K7, MAPK14, GSN, ARHGDIB, AKAP12, DRG1, CD44, PEBP1, RRM1, KISS1), we identified genes whose expression was significantly opposite to at least five MSGs. We used microarrays to evaluate the modification in gene expression profile after donregulation of multiple metastasis suppressors (NME1, BRMS1, CD82, CDH1, CDH2, CDH11, CASP8, MAP2K4, MAP2K6, MAP2K7, MAPK14, GSN, ARHGDIB, AKAP12, DRG1, CD44, PEBP1, RRM1, KISS1) in the breast cancer cell line, MCF7. MCF7 cell line was transfected with siRNA targeting each of 19 metastasis suppressors (NME1, BRMS1, CD82, CDH1, CDH2, CDH11, CASP8, MAP2K4, MAP2K6, MAP2K7, MAPK14, GSN, ARHGDIB, AKAP12, DRG1, CD44, PEBP1, RRM1, KISS1). Two siRNA sequences (siRNA1 and siRNA2) were used for each metastasis suppressor. Two time points (48hr and 96hr) were considered as end of transfection in order to measure early and late effects of the metastasis suppressors downregulation.
