[Biologic effects of Tween 80 in combination with hyperthermia on human stomach cancer cell line BGC-823]

Cells of human stomach cancer cell line BGC-823 were treated with Tween 80 and hyperthermia 39 degrees C to 43 degrees C for 20 to 100 minutes. Normal human fibroblasts and mitomycin C were used as controls. The results showed Tween 80 greatly reduced the activation energy of BGC-823 cells. Synergistic effect was observed if applied with heat 39 degrees C. With the increase in temperature and time, the inhibitory effect on the cancer cells was gradually intensified. The lethal rate of heat 41 degrees C associated with Tween 80 was 5.2 times as that of heat alone. The inhibitory effect of heat 41 degrees C for 100 minutes combined with Tween 80 was equivalent to 43 degrees C for 100 minutes. In other words, the heat critical Temperature of BGC-823 cells was reduced about 2 degrees C. The measurement of membrane fluidity, SDH activity and the rest also showed heat 41 degrees C produced the highest synergy with Tween 80. The specific and sustained action exceeded that of mitomycin C. The response of the normal cells was mild and reversible. These studies suggest that the synergistic mechanism of Tween 80 and hyperthermia possibly lies on the cell plasma membrane system.