New potential cytotoxic and antitumor substances. III. In vitro effect of 3-benzazepine derivatives on P388 cells.

: 3-Benzazepine derivatives manifested cytotoxic effects in in vitro tests on lympholeukemia P388 cells. The most efficient derivative (QF 1), i. e. 7,8-dihydro-3,4,12-trimetoxy-7-dimethylamino-10,11-methylenedioxy-5H-indolo [1,2-b][3]benzazepine-5-on in a concentration as low as 5 microliter/ml, considerably inhibited only the incorporation of labeled uridine into P388 cell fractions. In in vitro experiments, this substance blocked cell proliferation. After its prolonged action, the number of dead cells increased and this also when its interaction with the cells lasted but a short time--the substance being removed from the medium. In all probability, the substance retains the cells in the G1/S phase. A marked synergistic effect of tubercidine was attained in the presence of the substance.