Identification of a chemoattractant for fibroblasts produced by human breast carcinoma cell lines

Serum-free, conditioned media from the human breast tumor cell line ZR-75-1 and three other breast tumor cell lines were each found to contain a potent chemoattractant for fibroblasts. The chemoattractant activity was characterized and found to reside in a high-molecular-weight (Mr greater than 100,000) protein. This activity was stable to heating to 56 degrees and from pH 3 to 11, but it was sensitive to trypsin and pepsin treatment and to reduction. When crude attractant was placed in vivo in a slowly releasing pump, a fibrous tissue mass that formed at the releasing site within 11 days was 3- to 5-fold larger than was that observed with pumps containing control medium. It is likely that the production of a chemoattractant for fibroblasts by breast tumor cells might contribute to the fibrotic involvement that is common in breast carcinomas.