deoxyguanosine-triphosphate and Melanoma

Enzymatic activity of DNA polymerase iota (Pol t) was analyzed in human uveal melanoma cell extracts, using an earlier elaborated approach. The Pol t activity was observed in seven out of eight malignant tumors, while it was absent in the normal uveal tract cells of the same patients. These findings serve as an additional confirmation of the Pol t oncogenic potential.

Topics: Aged; Biomarkers, Tumor; Deoxyadenine Nucleotides; Deoxyguanine Nucleotides; DNA Polymerase iota; DNA-Directed DNA Polymerase; Electrophoresis, Polyacrylamide Gel; Eye; Female; Humans; Male; Melanoma; Middle Aged; Uveal Neoplasms

Intracellular deoxyribonucleotide pools were examined before and after thymidine treatment in highly sensitive T-lymphoid cells, relatively resistant B-lymphoid cells and moderately sensitive melanoma cells. Among the 4 cell lines studied, proportions of the 4 deoxyribonucleotide pools varied appreciably while ribonucleotide profiles were similar. The ratio of dGTP to dCTP increased with sensitivity to thymidine. Increase in dTTP levels with increasing thymidine concentration was dependent on sensitivity of cells to thymidine and was accompanied by reduction in the dCTP pool. dGTP levels increased as did dTTP levels in all cells, while dATP pool expansion correlated with thymidine sensitivity. The results indicate an additional aspect of purine deoxyribonucleotide involvement in the growth inhibitory effects of thymidine.

Topics: B-Lymphocytes; Cell Line; Deoxycytosine Nucleotides; Deoxyguanine Nucleotides; Deoxyribonucleotides; Humans; Melanoma; T-Lymphocytes; Thymidine; Thymine Nucleotides