Fibroblast migratory factor derived from mouse colon carcinoma cells: Potential roles of fibronectin in tumor stroma formation

Mouse colon carcinoma cell line colon 38 was used to investigate migratory factor for fibroblasts because marked fibrotic tissue was associated with t hese cells growing at transplanted sires and liver metastases in vivo. Migr ation-inducing activity was detected in the serum-free culture supernatants of colon 38 cells, as shown by the Boyden chamber assays using NIH3T3 cell s as target cells. The active substance was partially purified by a combina tion of anion-exchange, hydrophobic, and gel-permeation chromatography. An approximate relative molecular mass of the active substance was estimated t o be between 100,000 and 400,000, judging from the eluting position in the gel-permeation chromatography. The migratory activity in the partially puri fied preparation was removed by incubation with beads coated with an anti-m ouse fibronectin antibody. NIH3T3 cells incubated in the presence of cultur e supernatants of colon 38 cells exhibited higher growth rate, organized ac tin filaments, and increased chondroitin sulfate and hyaluronan. Fibronecti n did not elicit such effects and partially purified migratory factor showe d relatively low activity in these regards. Thus, colon 38 cells seem to se crete fibronectin and other soluble substances, which induce tumor stroma f ormation through migration and activation of host fibroblasts. J. Cell. Bio chem. 80:635-646, 2001. (C) 2001 Wiley-Liss, Inc.