L 86-8275, a flavone of novel structure, was shown to be a kinase inhi
bitor and to possess surprising potent antiproliferative potency (IC50
=0.1-0.15 mu M) on various tumor cell lines after long period of incub
ation. Short period of incubation was significantly less effective (IC
50=133 mu M). In vitro L 86-8275 showed almost no cross-resistance on
L 1210 mouse leukemia tumor cell line 110-fold resistant to doxorubici
n. In vivo significant antitumoral effects were seen with xenografted
lung, colon, mammary and ovarian tumors as well as glioblastoma. T/C v
alues ranged from 29 to 86% and were comparable to standard chemothera
peutic treatment. Optimal schedule required daily oral application of
L 86-8275.