Sulforaphane induces apoptosis in adipocytes via Akt/p70s6k1/Bad inhibition and ERK activation

Sulforaphane (SFN), an isothiocyanate isolated from cruciferous vegetables, possesses anti-oxidant and anti-cancer bioactivities. Moreover, SFN exerts its pro-apoptotic effects in some cancer lines. However, the effects and mechanisms of SFN on the regulation of apoptosis of adipocytes are still unknown. In this study, we found that SFN induced significant apoptosis in 3T3-L1 adipocytes and markedly decreased the cellular lipid content. Western blot demonstrated that SFN-induced apoptosis was mediated via the mitochondrial apoptosis pathway based on increased cleavage of poly-ADP-ribose-polymerase (PARP), release of cytochrome c into the cytoplasm, and activation of caspase-3, as well as decreased Bcl-2/Bax ratio. In addition, SFN markedly decreased phosphorylation of Akt and downstream proteins, p70s6k1 and Bad, and increased phosphorylation of ERK. Therefore, our findings clarified that SFN could induce 3T3-L1 adipocyte apoptosis via down-regulation of the Akt/p70s6k1/Bad pathway and up-regulation of the ERK pathway, suggesting SFN may be a promising agent for the treatment or prevention of obesity.