Effect of the Purine Derivative Myoseverin and of Its Analogues on Cultured Hybridoma Cells

Two 2,6,9-trisubstituted purine derivatives, 9-isopropyl-2,6-bis[(4-methoxybenzyl)amino]-9H-purine (myoseverin, PMYO, 1) and 9-isopropyl-2,6-bis[(2-methoxybenzyl)amino]-9H-purine (OMYO, 2), and two 6,9-disubstituted derivatives, 9-isopropyl-6-[(4-methoxybenzyl)amino]-9H-purine (3) and 9-isopropyl-6-[(2-methoxybenzyl)amino]-9H-purine (4), were synthesized with the aim to examine their cell proliferation inhibiting activity, and possible additional effects in cultures of hybridoma cells producing monoclonal antibody. The substances were tested over a concentration range from 0.003 to 30 μmol l-1. The most active compound 1 caused a total loss of cell viability at 1 μmol l-1, while its isomer 2 showed the same effect at 10 μmol l-1 concentration. In the presence of compound 1, but not of compound 2, the character of the cell cycle phases profile changed dramatically, most cells being arrested in the G2/M phase. At intermediate concentrations of compound 2 a substantially higher viable cell concentration was observed, relative to control. These differences demonstrated the principal significance of the position of the methoxy groups on the benzene rings for the biological effect. The 6,9-disubstituted derivatives 3 and 4 were without significant effect in the whole range of concentrations tested. The enhancement of monoclonal antibody production, observed in certain concentration intervals of added substances, was of marginal character.