THE EFFECT OF HEAT SHOCK ON THE AUTOCRINE FUNCTIONS IN TUMOR AND NORMAL-CELLS

The influence of heat shock (44 degrees C, 30 min) on the ability of tumor cells (A-549 line from human lung adenocarcinoma, PS-103 line (3 sb clone) from mouse sarcoma) and normal fibroblasts (NIH-3T3 line from mouse embryos) to secrete growth regulatory factors was studied. It was found that after the heat shock the substances which increased the intensity of [H-3]-thymidine incorporation into cellular DNA appeared in the serum-free culture medium conditioned by the tumor cells. The temporary acidification (pH 2.0, 1 hour) of those conditioned media caused a significant change in their properties. They gained the ability to inhibit DNA synthesis. The heat shocked normal fibroblasts were shown to secrete factors inhibiting DNA synthesis and their activity in most cases was not changed after the temporary acidification. Thus, we revealed that heat shock differentially influenced the autocrine functions in the tumor and normal cells.