Physical and chemical composition of subcellular fractions from tumor cells treated with metabolic inhibitors or hormones.

Line 10 guinea pig hepatoma cells are resistant to killing by antibody plus guinea pig complement but not by antibody plus human complement. Agents that increase (metabolic inhibitors) or decrease (hormones) the sensitivity of the cells to killing by antibody plus complement were examined for their effects on the chemical, physical, and enzymic composition of the cells. The effects of these agents on the chemical and enzymic characteristics of isolated plasma membrane and intracellular fractions of these cells were also measured. Adriamycin treatment resulted in a decrease in the amount of ribonucleoprotein and smooth endoplasmic reticulum isolated from the cells as compared to untreated cells. Hormone (insulin or hydrocortisone)-treated cells were enhanced in their yield of this fraction but were decreased in their yield of mitochondria as compared to controls. Generally, the drug-treated cells were decreased, whereas hormone-treated cells were enhanced, in protein, lipid phosphate, and total phosphate content, as compared to untreated controls. This pattern was also noted in the plasma membrane fraction of the cells and, in several cases, in intracellular membrane fractions. These data suggest that the protein, lipid phosphate, and total phosphate content of the plasma membrane and intracellular membranes of these cells may correlate with their ability to resist humoral immune attack.