Effects of 8-Aminoguanosine on the Toxicity of Guanosine and Deoxyguanosine for Malignant and Normal Lymphoid Cells

The toxicity of guanosine and deoxyguanosine in the presence or absence of the purine nucleoside phosphorylase inhibitor, 8-aminoguanosine, for malignant lymphoid cell lines and mitogen-stimulated peripheral blood lymphocytes has been studied. Deoxyguanosine inhibited the proliferation of lymphoid cells more strongly than guanosine. Addition of 100 microM 8-aminoguanosine neither enhanced nor diminished the toxicity of guanosine to the lymphoid cells. Only the toxicity of deoxyguanosine for the leukemic T cell line, MOLT 4, and the leukemic nonBnonT cell line, KM-3, was enhanced by the addition of 100 microM 8-aminoguanosine. These data suggest a possible role of purine nucleoside phosphorylase inhibitors in the treatment of lymphoproliferative disorders of the T-acute lymphoblastic leukemia (ALL) as well as the nonBnonT-ALL subclass.