Synthesis and evaluation of novel 7-azaindazolyl-indolyl-maleimide derivatives as antitumor agents and protein kinase C inhibitors.

A series of novel 7-azaindazolyl-indolyl-maleimides were synthesized and evaluated for their antiproliferative activity in vitro against various human cancer cell lines and protein kinase C inhibitory activity. Compounds 8a-c, 8e and 14a were the most promising compounds against K562, A549, ECA-109, KB and SMMC-7721 cell lines in vitro. Compounds 9a-j showed moderate PKC inhibition. Further mechanism of action studies revealed that the antiproliferative activity of compound 8b in KB cells might involve the mitochondria-mediated apoptosis pathway.