5--deoxy-5--methylthioinosine and Leukemia

5'-Deoxy-5'-methylthioadenosine and 5'-deoxy-5'-methylthioinosine, which are metabolized to the methionine precursor, 5-methylthioribose-1-phosphate, by 5'-deoxy-5'-methylthioadenosine phosphorylase and purine nucleoside phosphorylase, respectively, can serve as sources of methionine for cultured HL-60 promyelocytic leukemia cells. CCRF-CEM T-cell leukemia cells, which lack 5'-deoxy-5'-methylthioadenosine phosphorylase, convert 5'-deoxy-5'-methylthioinosine (but not 5'-deoxy-5'-methylthioadenosine) to methionine; this conversion is blocked by purine nucleoside phosphorylase inhibitors. Therefore, the pathway for the conversion of 5-methylthioribose-1-phosphate to methionine is present in both human leukemic lines.

Topics: Adenosine; Cells, Cultured; Deoxyadenosines; Humans; Inosine; Leukemia; Leukemia, Myeloid, Acute; Methionine; Methylthioinosine; Purine-Nucleoside Phosphorylase; T-Lymphocytes; Thionucleosides