Millepachine (
MIL) was a novel
chalcone that was separated from Millettia pachycarpa Benth (Leguminosae). We found
MIL induced apoptosis through activating NF-κB pathway both in SK-OV-3 and A2780S cells. Western blot showed that
MIL increased the levels of IKKα, p-IKKα/β, p-IκBα and NF-κB (p65)
proteins, and decreased the expression of IκBα
protein. Immunohistochemistry analysis indicated that translocation of NF-κB into the nucleus increased in both
ovarian cancer cells. EMSA assay proved
MIL enhanced NF-κB
DNA-binding activity in the nuclear. That specific NF-κB inhibitors alleviated
MIL-induced apoptosis suggested NF-κB activation showed a pro-apoptotic function in SK-OV-3 and A2780S cells. Since NF-κB could be activated by double strand breaks and showed a pro-apoptotic function in the DNA damage response, SCGE assay and western blot revealed that
MIL caused
DNA strand breaks and significantly increased the level of p-
ATM protein and further increased the levels of p-IKKα/β and NF-κB (p65)
protein in SK-OV-3 and A2780S cells, while a specific ATM inhibitor could alleviated these effects. Moreover,
Topoisomerase II drug screening kit and computer modeling assay were used to prove that
MIL induced the production of linear
DNA and inhibited the activity of
topoisomerase II through binding with
Topoisomerase II-Cleaved
DNA complex to stabilize the complex. Taken together, our results identified that
MIL exhibited anti-
tumor activity through inhibiting
topoisomerase II activity to induce
tumor cells DNA damage, and
MIL-activated NF-κB pathway showed a pro-apoptotic function in response to DNA damage.