Hyperthermia and surface morphology of P388 ascites tumour cells: effects of membrane modifications.

The quantitative distribution of cell surface alterations of heated P388 ascites tumour cells was determined by scanning electron microscopy. Cells harvested from host animals maintained on a standard rodent chow diet or one high in saturated fatty acids responded differently, to identical hyperthermic treatment in vitro, to cells obtained from animals on a highly unsaturated diet. The morphological response of cells from chow fed animals was modified by addition to the incubation medium, of procaine, a membrane-active drug. The pattern of response observed after these cells were heated in the presence of procaine resembled that seen following heat treatment of ascites cells obtained from animals fed diet high in unsaturated fatty acids. These data are consistent with the hypothesis that a cell's response to hyperthermic insult is related to its membrane fluidity at the time of treatment.