Bone is a common site of metastasis for breast cancer and the mechanisms of metastasis are not fully elucidated. The purpose of our study was to characterize temporal and molecular dynamics of adhesive interactions between human breast cancer cells (HBCC) and human bone marrow endothelium (HBME) with piconewton resolution using atomic force microscopy (AFM). In adhesion experiments, a single breast cancer cell, MDA-MB-231 (MB231) or MDA-MB-435 (MB435) was attached to the AFM cantilever and brought into contact with a confluent HBME monolayer for different time periods (0.5 to 300 sec). The forces required to rupture individual molecular interactions and completely separate interacting cells were analyzed as measures of cell-cell adhesion. Adhesive interactions between HBME and either MB231 or MB435 cells increased progressively as cell-cell contact time was prolonged from 0.5 to 300 sec due to the time-dependent increase in the number and frequency of individual adhesive events, as well as to the involvement of stronger ligand-receptor interactions over time. Studies of the individual molecule involvement revealed that Thomsen-Friedenreich antigen (TF-Ag), galectin-3, integrin-β1, and integrin-α3 are all contributing to HBCC/HBME adhesion to various degrees in a temporally defined fashion. In conclusion, cell-cell contact time enhances adhesion of HBCC to HBME and the adhesion is mediated, in part, by TF-Ag, galectin-3, integrin-α3, and integrin-β1.

骨是乳腺癌转移的常见部位，其转移机理尚未完全阐明。我们研究的目的是使用原子力显微镜（AFM）来表征皮康酮分辨率下人乳腺癌细胞（HBCC）与人骨髓内皮细胞（HBME）之间的粘附相互作用的时间和分子动力学。在黏附实验中，将单个乳腺癌细胞MDA-MB-231（MB231）或MDA-MB-435（MB435）连接到AFM悬臂，并与融合的HBME单层接触不同的时间段（0.5至300秒）。分析了破坏单个分子相互作用和完全分离的相互作用细胞所需的力，作为细胞与细胞粘附的量度。HBME与MB231或MB435细胞之间的粘附相互作用随着细胞与细胞之间的接触时间从0.5秒延长到300秒而逐渐增加，这是由于单个粘附事件的次数和频率随时间增加，以及随着时间的推移配体-受体相互作用。对单个分子参与的研究表明，Thomsen-Friedenreich抗原（TF-Ag），galectin-3，整联蛋白-β1和整联蛋白-α3均以时间确定的方式在不同程度上促进了HBCC / HBME的粘附。总之，细胞间的接触时间增强了HBCC对HBME的粘附，并且粘附部分地由TF-Ag，galectin-3，整联蛋白-α3和整联蛋白-β1介导。以及随着时间的推移更强的配体-受体相互作用的参与。对单个分子参与的研究表明，Thomsen-Friedenreich抗原（TF-Ag），galectin-3，整联蛋白-β1和整联蛋白-α3均以时间确定的方式在不同程度上促进了HBCC / HBME的粘附。总之，细胞间的接触时间增强了HBCC对HBME的粘附，并且粘附部分地由TF-Ag，galectin-3，整联蛋白-α3和整联蛋白-β1介导。以及随着时间的推移更强的配体-受体相互作用的参与。对单个分子参与的研究表明，Thomsen-Friedenreich抗原（TF-Ag），galectin-3，整联蛋白-β1和整联蛋白-α3均以时间确定的方式在不同程度上促进了HBCC / HBME的粘附。总之，细胞间的接触时间增强了HBCC对HBME的粘附，并且粘附部分地由TF-Ag，galectin-3，整联蛋白-α3和整联蛋白-β1介导。