An interaction between human colon carcinoma cells and hepatocytes activates transforming growth factor-beta 1 in vitro

We established in vitro heterotypic co-cultures of a human colon carcinoma cell line, HT-29, and a human hepatocyte line, tPH5CH, using transwells to investigate possible interactions between colon carcinoma cells and hepatoc ytes during the metastatic process. Co-culture, but not HT-29 conditioned m edium, inhibited tPH5CH cell proliferation, and this inhibition was blocked by an anti-TGF-beta 1 antibody. Significantly more activated TGF-beta 1 wa s released by co-culture than by each cell line cultured alone, whereas the re were no significant differences between the total TGF-beta 1 released by the individual cultured cell Lines and that released by co-culture. These data indicate that an interaction between human colon carcinoma cells and h epatocytes activates TGF-beta 1 in vitro. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.