X609, a novel manassantin A derivative, exhibits antitumor activity in MG-63 human osteosarcoma cells in vitro and in vivo.

Manassantin A has been well-established as an inhibitor of HIF-1. In the present study, a new manasantin A derivative, X609, with decreased stereochemical complexity, rendering it amenable to a simplified synthesis scheme, was synthesized and was found to increase HIF-1 inhibitory activity. X609 exhibited antiproliferative activity in a broad spectrum of tumor cell lines, via HIF-1-dependent mechanisms. X609 may induce apoptosis in MG-63 cells through activation of the mitochondrial pathway. Oral administration of X609 significantly inhibited the growth of human osteosarcomas implanted into nude mice. In light of the results of the present study, it may be possible to develop X609 for use as a novel antitumor agent, which targets human osteosarcoma.