流体剪切力下CD44-HA介导的MDA-MB-231细胞及HL60细胞的滚动黏附

CD44-HA Mediate Adhesion of MDA-MB-231 Cells and HL60 Cells under Fluid Shear Flow

目的探究胞外基质中的透明质酸(hyaluronic acid,HA)如何调控血流中CD44+肿瘤细胞的黏附滚动行为。方法采用平行平板流动腔装置,观察记录流场中MDA-MB-231细胞及HL60细胞在固定HA上的运动,提取细胞滚动黏附特征参数。结果MDA-MB-231细胞在HA底板上的黏附受到HA浓度的正向调控,但不受HA分子量影响;与物理吸附相比,生物素-亲和素固定的HA可显著提高细胞的黏附比率。在30~50 mPa剪切力范围内,剪切力的增加加快了细胞的滚动速度,降低了细胞的黏附比率,但对细胞的栓缚时间影响不大。同样流场中,与MDAMB-231细胞比较,CD44表达水平较低的HL60细胞在HA底板上的栓缚时间短、滚动速度快、黏附比率低(<1.5%)。结论流体剪切力可能通过调节CD44-HA的结合速率而非解离速率来调控MDA-MB-231细胞的滚动速度;CD44-HA相互作用参与HL60细胞的初始黏附,但不起主要作用。研究结果为抗肿瘤药物的开发提供参考。

Objective To explore how hyaluronic acid(HA)in extracellular matrix regulates the adhesion of CD44+tumor cells.Methods MDA-MB-231 cells or HL60 cells were perfused in a parallel plate chamber.The movement of cells over immobilized HA was observed and analyzed to obtain the characteristics of cell adhesion and rolling.Results The adhesion number of MDA-MB-231 cells on HA substrate was positively regulated by HA concentration,but not by HA molecular weight.Compared with physically adsorbed HA,immobilized HA by avidin-biotin could significantly improve the cell adhesion ratio.With the increase of shear stress in the range of 30-50 mPa,the rolling velocity of cells increased and the adhesion ratio decreased,but the tether lifetime of cells was not affected.In the same flow field,compared with MDA-MB-231 cells,HL60 cells with low expression of CD44 rolled more quickly on immobilized HA,with shorter tether lifetime and much lower adhesion ratio(<1.5%).Conclusions Fluid shear stress might mediate the rolling velocity of MDA-MB-231 cells by regulating the CD44-HA association rate rather than their dissociation rate.The interaction between CD44 and HA is involved in the initial adhesion of HL60 cells,but it does not play a major role.This study will provide references for the design of anti-tumor drugs.