Inhibitory effects of novel festuclavine derivatives on nucleoside uptake and incorporation into DNA and RNA in human lymphoid leukemia Molt 4B cells.

Effects of festuclavine derivatives on nucleoside uptake by human lymphoid leukemia Molt 4B cells and on incorporation into TCA-insoluble materials in the cells were examined. The uptake and incorporation of uridine or thymidine were suppressed by festuclavine (EN01), 13-bromo-1-cyclopropylmethyl-festuclavine (EN02), 1-(4-chloro-benzenesulfonyl)festuclavine (EN03) and 1-cyclopentyl festuclavine (EN04) at 10-50 microM. Among these compounds, EN02 was most effective and at 50 microM it completely suppressed cellular uptake of the nucleosides and their incorporation into TCA-insoluble materials inhibiting the cellular proliferation. EN03 and EN04 moderately inhibited the transport and incorporation of the nucleosides in dose-dependent manners, while the mother compound EN01 had the least inhibitory effect. These findings indicated that alkylation at the indole nitrogen in combination with bromination at C-13 of the festuclavine molecule strengthened its inhibitory action on nucleoside uptake to a remarkable extent. The inhibition curves of nucleoside incorporation into TCA-insoluble materials showed quite similar dose-dependence to those of the inhibition curves for cellular nucleoside transport. These results suggest that the inhibitions of DNA and RNA syntheses by the festuclavine derivatives are due to the depressed transport of nucleosides into the leukemia cells.