Stimulation of TIMP-1 and metalloproteinase production in co-cultures of human tumor cells and human fibroblasts

The co-cultures of five different human tumor cell lines with human normal fibroblasts significantly stimulated the production of tissue inhibitors of metalloproteinases-1 (TIMP-1) when compared to cultures of individual cells. In the co-culture of T24 human urinary bladder carcinoma cells and CCD18 human fibroblasts, production of both TIMP-1 and metalloproteinases was stimulated, and the stimulatory effects were dependent on the cellular ratio between the fibroblasts and carcinoma cells. On day 6 of culture, collagenase and stromelysin were stimulated at a ratio of CCD18 fibroblasts to T24 cells of 1:0.1, while the maximum TIMP-1 production occurred at a ratio of 1:1. Thus, the cellular ratio in the interaction of carcinoma cells with host fibroblasts affects the production of TIMP-1 and metalloproteinases and hence modulates the balance between them.