INHIBITION OF NUCLEAR FACTOR ??B ACTIVATION IN BXPC-3 CELLS BY GENISTEIN IS MEDIATED VIA NOTCH-1 SIGNALING PATHWAY

Abstract

Pancreatic cancer remains the fourth most common cause of cancer related death in the United States. Therefore, novel strategies for the prevention and treatment are urgently needed. Genistein is a prominent isoflavonoid found in soy products and has been proposed to be responsible for lowering the rate of pancreatic cancer in Asians. However, the molecular mechanism(s) by which genistein elicits its effects on pancreatic cancer cells has not been fully elucidated. We have previously shown that genistein induces apoptosis and inhibits the activation of nuclear factor κB (NF-κB) pathway. Moreover, Notch signaling is known to play a critical role in maintaining the balance between cell proliferation, differentiation and apoptosis, and thereby may contribute to the development of pancreatic cancer. Hence, in this study, we investigated whether there is any cross-talk between Notch and NF-κB during genistein-induced apoptosis in BxPC-3 pancreatic cancer cells. We have used multiple cellular and molecular approaches such as MTT assay, apoptosis assay, gene transfection, Western blotting and EMSA for measuring DNA binding activity of NF-κB. We found that genistein inhibits cell growth and induces apoptotic processes in BxPC-3 pancreatic cancer cells. This was partly due to inhibition of Notch-1 activity. BxPC-3 cells transfected with Notch-1 cDNA showed induction of NF-κB activity and this was inhibited by genistein treatment. From these results, we conclude that the inhibition of Notch-1 and NF-κB activity and their cross-talk provide a novel mechanism by which genistein inhibits cell growth and induces apoptotic processes in pancreatic cancer cells.