EFFECT OF TRYPAN BLUE ON THE ACTIVITY OF LYSOSOMAL-ENZYMES, TUMOR-GROWTH AND CELL ULTRASTRUCTURE IN B16 MELANOTIC MELANOMA IN MICE

Trypan blue is known to act as a lysosome membrane destabilizer. We in vestigated 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. Th e mice were given subcutaneous injections of the suspension of B16 cel ls (10(6)), and then received the trypan blue solution intraperitoneal ly in four divided doses, reaching the total dose of 0.1 mg/g b.w. (gr oup 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 w ith melanoma cells only. The animals were killed 2 weeks after the beg inning of the experiment. We found that the activity of lysosome hydro lases 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 I I was accelerated, and some ultrastructural changes in the melanoma ce lls were observed. These included irregular shape of the nucleus, unev en dispersion of the chromatin, increased number of premelanosomes and Golgi structures. The number of lysosomes, however, remained unaltere d. 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 tryp an blue.