Certain of the acridine dyes were found by Lewis et el (1) to inhibit tunaor growth in mice when incorporated in the diet. Tumor growth, however, may be influenced not only directly by selective action on the tumor but indirectly by its influence on the host animal. Since these dyes are toxic it was considered of interest to compare the effect of one of the dyes, acriflavine, not only on the tumor but also on the host.
In order for a chemical compound to cause the death of tumor cells it is necessary that a certain minimal concentration of the chemical be maintained in the cells for a sufficient time. A high concentration for a short period of time or a lower concentration for a longer period of time may be equally effective.
Acriflavine, when injected into the peritoneal cavity of Krebs 2 ascites tumor-bearing mice promptly entered all tumor cells and could be detected by its fluorescence, ttematoporphyrin, on the contrary, did not enter the living cells, but was promptly absorbed by dead ones. These cells fluoresced brilliantly red.
Thus with Krebs ascites tumor-bearing animals treated with acriflavine it was possible to determine if the dye had entered the ascites cells and whether or not any of the cells present at the time of observation were dead cells.
The effect of acriflavine on the survival and growth of immature non-tumor-bearing mice was determined as a measure of toxicity. All mice were fed a diet composed of 7 parts casein, 4 parts salt mixture, 68 parts sucrose, 2 parts Vitab, 10 parts nmzola, and 9 parts of inert filler. Eight groups of 15 mice were treated as follows: