Selective uptake of para-boronophenylalanine increases in amelanotic melanoma cells transfected by the tyrosinase gene

To investigate the mechanism of uptake of para-boronophenylalanine (p-BPA), a capture agent for boron neutron capture therapy (BNCT) of melanoma and b rain tumour, into melanoma cells, we studied the relationship between melan in synthesis and the concentration of boron using tyrosinase-deficient mous e amelanotic melanoma cells (A1059) and melanotic melanoma cells (TA1059), A1059 was established from mouse B16F10 cells, and TA1059 was constructed b y transfecting human tyrosinase cDNA into A1059. The melanin content of TA1 059 was 1.5-fold higher than that of B16F10, and was undetectable in A1059. The order of p-BPA uptake was TA1059 > B16F10 > A1059 at the time points e xamined, and the boron content of TA1059 was approximately 1.5-fold higher than that of B16F10. our experimental findings indicated that melanin synth esis is a very important factor for characterizing the increase in accumula tion of p-BPA in melanoma cells. A significant difference in boron uptake i nto TA1059 was observed between p-BPA and meta-BPA (m-BPA), but there were no apparent differences in the case of A1059. The difference in accumulatio n of p-BPA and m-BPA could be due to differences in the properties of p-BPA as a tyrosine analogue needed for melanin synthesis. (C) 2000 Lippincott W illiams & Wilkins.