Anti-proliferative activity of L-651,582 correlates with calcium-mediated regulation of nucleotide metabolism at phosphoribosyl pyrophosphate synthetase

Autor: Nancy Behrens, Robert C. Boltz, Donald Hupe
Rok vydání: 1990
Předmět:
Zdroj: Journal of Cellular Physiology. 144:457-466
ISSN: 1097-4652
0021-9541
DOI: 10.1002/jcp.1041440313
Popis: L-651,582, 5-amino-(4-(4-chlorobenzoyl)-3,5-dichlorobenzyl)-1, 2,3-triazole-4-carboxamide, is an antiproliferative and antiparasitic agent which inhibits nucleotide metabolism in mammalian cells. The drug equivalently inhibited 3H-hypoxanthine, 14C-adenine, and 14C-formate incorporation into nucleotide pools in Madin-Darby bovine kidney (MDBK) cells, suggesting depletion of the supply of phosphoribosyl pyrophosphate, (PRPP), required for each of these independent pathways. Inhibition of nucleotide metabolism correlated with inhibition of proliferation for three cell types with differing sensitivities toward the drug. L-651,582 inhibited incorporation of 3H-hypoxanthine into nucleotide pools with either glucose, uridine, or ribose as carbon source suggesting a block at PRPP synthetase, rather than a block in a pathway supplying ribose-5-phosphate. PRPP synthetase was not inhibited directly by the compound, indicating regulation of the enzyme in intact cells. Drug treatment did not kill cells but reduced the fraction of cells in S and G2/M while increasing the population in G1. Inhibition of uptake of 45Ca was demonstrated at concentrations identical to those required for inhibition of nucleotide metabolism or proliferation. Inhibition of cellular PRPP biosynthesis rates were also observed using EGTA to lower calcium levels. These data suggest a previously unrecognized link between calcium entry, the regulation of nucleotide biosynthesis at PRPP synthetase, and the rate of proliferation of mammalianmore » cells.« less
Databáze: OpenAIRE
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