[Inhibitory effect of bone sialoprotein silencing on the adhesion ability of breast cancer cells to bone matrix].

We performed this research mainly to explore the effect of bone sialoprotein (BSP) silence by siRNA on the adhesion ability to bone matrix of bone-seeking breast cancer cells (MDA-MB-231BO). Also we aimed to provide experimental data for prevention and treatment of breast cancer bone metastasis by targeting BSP. We explored the effects of BSP gene silence on characteristics of bone-seeking breast cancer cells: proliferation by MTS[3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] assay, bone adhesion ability by a mouse bone adhesion model in vitro, morphology of the cells by SEM, and secretion of transforming growth factor-beta1 (TGF-beta1) and receptor activator of nuclear factor-kappa B ligand (RANKL) by ELISA kits. We performed intra-cardiac injection in nude mice to explore bone metastatic ability of different cell lines. The results showed that knockdown of BSP significantly inhibited the proliferation of MDA-MB-231BO cells and their adhesion to bone matrix. We also observed bone destruction caused by bone resorption around some adhering cells. The appearances of the cells changed in BSP gene silenced group, and the secretion of TGF-beta1 and RANKL decreased. The results showed BSP gene silence can partial inhibition bone metastasis of breast cancer cells in nude mice by X-ray assay and hematoxylin-eosin staining. Based on our research, siRNA-mediated BSP silencing can inhibit proliferation and adhesion to bone matrix of bone-seeking breast cancer cells and change their surface structure, thus inhibits their bone metastatic ability.