Migration of tumor cells to organ-derived chemoattractants.

Certain tissues contain unique factors which are chemotactic for metastatic tumor cell lines. Extracts of bone, brain, liver, and lung were tested for their ability to promote either the migration or the chemoinvasion, i.e., their penetration through a reconstituted basement membrane barrier, of various metastatic tumor cells. Using a modified Boyden chamber assay for chemotaxis, B16-Br2 melanoma cells, which metastasize to brain, migrated most actively to brain extract. Lung-directed T241-PM2 fibrosarcoma cells migrated selectively to lung extract. Further, murine M50-76 reticulum cell sarcoma cells, which metastasize to liver and ovaries, were preferentially attracted to liver extract, and MCF-7 breast adenocarcinoma cells with high bone and brain colonization potential were found to migrate most actively to bone and brain extracts. Partial purification of tissue extracts showed that the factors in brain and liver are of different molecular weights. These data suggest that tissue-specific factors in different target tissues attract tumor cells which home to those sites.