Effect of gelatins on human cancer cells in vitro.

Three types of gelatins were tested for their antiproliferative activities in vitro against three human tumor cell lines (K-562; erythroleukemia, HCT-15; colon carcinoma, AGS; gastric carcinoma) with viable cell count and tritium-thymidine ((3)H-TdR) uptake by those cells. Porcine skin (PS) gelatin exerted the strongest antiproliferative activity of all three gelatins. Bovine bone (BB) gelatin did not exert such an activity. PS gelatin exerted antiproliferative activity against K-562 cells also in a serum-free medium. The serum-free medium contains two growth factors, insulin and transferrin, as well as nutrients. The activity of PS gelatin was not interfered by addition of insulin and transferrin to the medium. Effect of diluting a K-562 cell-concentration on the activity of PS gelatin was tested. Diluting the cell concentration did not affect the activity of PS gelatin. Moreover, the conditioned medium in which K-562 cells had been cultured did not stimulate the proliferation of K-562 cells. In conclusion, PS gelatin suppress the proliferation of human tumor cell lines in vitro. The antiproliferative activity of PS gelatin might not be attributed to trapping growth factors or autocrine mediators.