Effect of trypan blue on the activity of lysosomal enzymes, tumor growth and cell ultrastructure in B16 melanotic melanoma in mice.Neoplasma. 1995; 42(4):173-8.N
Trypan blue is known to act as a lysosome membrane destabilizer. We investigated the effect of this dye on the activity of cathepsin D, acid phosphatase and arylsulfatase in tissue homogenates of B16 melanotic melanoma, transplanted subcutaneously in C57BL/6J black male mice. We also examined the tumor growth and the ultrastructure of its cells. The mice were given subcutaneous injections of the suspension of B16 cells (10(6)), and then received the trypan blue solution intraperitoneally in four divided doses, reaching the total does of 0.1 mg/g b.w. (group I) or 0.4 mg/g b.w. (group II). The dye was administered each other day after the tumor transplantation. The control mice were injected with melanoma cells only. The animals were killed 2 weeks after the beginning of the experiment. We found that the activity of lysosome hydrolases was increased by 30% to 50% in groups I and II, respectively, as compared to the control animals. The tumor growth in groups I and II was accelerated, and some ultrastructural changes in the melanoma cells were observed. These included irregular shape of the nucleus, uneven dispersion of the chromatin, increased number of premelanosomes and Golgi structures. The number of lysosomes, however, remained unaltered. We postulate that the trypan blue promotes tumor growth through the enhancement of the activity of lysosomal hydrolases; this may be due to the increased permeability of lysosome membranes caused by the trypan blue.