Abstract
Once breast cancer cells grow aggressively and become lodged in the skeleton through migration and invasion, they interact with bone microenvironment and accelerate much more tumor growth and bone destruction. We investigated whether liensinine and nuciferine, major active components in Nelumbo nucifera (lotus), could prevent breast cancer cell-mediated bone destruction. Liensinine and nuciferine inhibited the growth of MDA-MB-231 and MCF-7 human breast cancer cells by inducing apoptosis and inhibiting proliferation via cell cycle arrest. Liensinine treatment led to the increased Bax/Bcl-2 ratio, activation of caspase-3, and subsequent cleavage of PARP. Liensinine also displayed significant inhibition on the migration and invasion of both MDA-MB-231 and MCF-7 human breast cancer cells compared with nuciferine. In addition, liensinine and nuciferine inhibited the receptor activator of nuclear factor kappa-B ligand- (RANKL-) induced osteoclast differentiation in mouse bone marrow macrophage cells and mature osteoclast-mediated bone resorption. Furthermore, oral administration of liensinine reduced the osteolysis in nude mice with intratibial injection of MDA-MB-231 cells. Collectively, liensinine and nuciferine may be promising candidates for preventing and treating breast cancer bone metastasis and the resulting osteolytic bone loss by targeting both cancer cells and osteoclasts. Liensinine has more potent anticancer and antibone resorptive activities than nuciferine.