Studies on the 67Ga uptake mechanism by Ehrlich ascites tumor cells

In order to obtain more information concerning the mechanism of Gallium (67Ga) accumulation in malignant tissue, an investigation was carried out using Ehrlich ascites tumor cells. Chlorpromazine, a phospholipid stabilizer decreased the uptake of 67Ga and Calcium 45 (45Ca) by the cells at low dose, but increased them at high dose. On the other hand, the uptake of both radionuclides by the cells was inhibited by ruthenium red, a Ca ATPase inhibitor in a dose dependent manner. The time course of 67Ga and 45Ca uptake were quite different from each other. Moreover, the subcellular distribution patterns of 67Ga and 45Ca were also different from each other; 67Ga accumulated in the lysosomal fraction and 45Ca mainly in the mitochondrial fraction. These results suggest that there may be a commonality for 67Ga and 45Ca uptake by the tumor cells, whereas the behaviour of these two radionuclides in the cells is dissimilar.