Organ-specific chemotactic factors present in lung extracellular matrix

The preferential colonization of a distant organ by a circulating tumor cell (organ specific metastasis) may be regulated by chemotactic factors present within the extracellular matrix of the host organ. Organ-specific extracellular matrix was prepared from murine kidney and lung by high salt extraction and DNAase/RNAase digestion. A soluble protein fraction (S2) from each of the matricies was obtained by 4 M guanidine extraction and was tested for organ-specific chemotactic activity in a modified Boyden chamber. The lung colonizing B16-F10 and B16-BL6 tumor cell lines demonstrated organ-specific motility only toward the lung extract. The low metastasizing B16 parental line and liver colonizing B16-L4b line showed no preference for either lung or kidney. The lung activity resolves into five fractions by gel filtration chromatography, with the highest activity eluting at Mr approximately 71,000. Chemotactic factors present in lung extracellular matrix may regulate the preferential colonization of an organ by stimulating the migration of tumor cells in a specific manner. These factors may be released during the degradation of the extracellular matrix.