Naphtho[1,2-b]furan-4,5-dione induces apoptosis and S-phase arrest of MDA-MB-231 cells through JNK and ERK signaling activation.

Naphtho[1,2-b]furan-4,5-dione (NFD), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exhibits anti-carcinogenic effect. The results of present study showed that NFD inhibited the proliferation of breast cancer MDA-MB-231 cells through the induction of S-phase arrest and apoptosis. NFD-induced S-phase arrest was associated with a marked decrease in the protein expression of cyclin A, cyclin B, and cyclin-dependent kinase (Cdk)2. NFD-induced apoptosis was characterized by increase of sub-G1 population, phosphatidylserine (PS) externalization, and activation of caspases. Moreover, up-regulation of Bad and down-regulation of Bcl-2, Bcl-X(L), and survivin led to the loss of mitochondrial membrane potential (DeltaPsim), the release of cytochrome c and sequential activation of caspase-9 and caspase-3. NFD activated c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal-regulated kinase (ERK) in MDA-MB-231 cells. Inhibitors of JNK (SP600125) and ERK (PD98059), but not p38 MAPK (SB203580) suppressed NFD-induced S-phase arrest and apoptosis in MDA-MB-231 cells. Both SP600125 and PD98059 attenuated Bad up-regulation, and reversed down-regulation of Bcl-2, Bcl-X(L), survivin, cyclin A, cyclin B, and Cdk2 in NFD-treated cells. Taken together, our data show that JNK and ERK-signaling pathways play important roles in NFD-mediated S-phase arrest and apoptosis of MDA-MB-231 cells.