Payne Stacey L, Hendrix Mary J C, Kirschmann Dawn A
Children's Memorial Research Center, Cancer Biology and Epigenomics Program, Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine at Northwestern University, Chicago, Illinois 60614, USA.
J Cell Biochem. 2006 Jul 1;98(4):827-37. doi: 10.1002/jcb.20792.
We have previously demonstrated that lysyl oxidase (LOX) is expressed in invasive breast cancer cells compared to poorly invasive cells. Additionally, we have recently shown that LOX regulates cell migration, a key step in the invasion process, through a hydrogen peroxide-dependent mechanism involving the focal adhesion kinase (FAK)/Src signaling complex. Here we further elucidate the role of LOX in cell motility/migration by examining the role of LOX in actin filament polymerization. We demonstrate that inhibition of LOX leads to an increase in phalloidin staining, directly associated with an increase in actin stress fiber formation. This increase in staining was confirmed by activity assays showing an increase in Rho activity with decreased LOX activity. Additionally, Rac and Cdc42 activity decreased with the reduction in LOX activity. Taken together, these data demonstrate a loss of a motogenic phenotype with decreased LOX activity. Finally, in order to elucidate the mechanism by which LOX regulates actin polymerization, we have demonstrated that LOX facilitates p130(Cas) phosphorylation, which allows for the binding to CAS related kinase (Crk) and formation of the p130(Cas)/Crk/DOCK180 signaling complex. Formation of this complex leads to an increase in Rac-GTP, which decreases actin stress fiber formation and increases formation of lamellipodium. These data demonstrate that LOX regulates cell motility/migration through changes in actin filament polymerization, which involve the regulation of the p130(Cas)/Crk/DOCK180 signaling pathway. Elucidating the role of LOX in the regulation of cell motility will allow the development of more effective therapeutic strategies to treat invasive/metastatic breast cancer.
我们之前已经证明，与低侵袭性细胞相比，赖氨酰氧化酶（LOX）在侵袭性乳腺癌细胞中表达。此外，我们最近发现，LOX通过一种涉及粘着斑激酶（FAK）/Src信号复合物的过氧化氢依赖性机制来调节细胞迁移，这是侵袭过程中的关键步骤。在这里，我们通过研究LOX在肌动蛋白丝聚合中的作用，进一步阐明LOX在细胞运动性/迁移中的作用。我们证明，抑制LOX会导致鬼笔环肽染色增加，这与肌动蛋白应激纤维形成的增加直接相关。活性测定证实了这种染色增加，结果显示随着LOX活性降低，Rho活性增加。此外，随着LOX活性降低，Rac和Cdc42活性也降低。综上所述，这些数据表明随着LOX活性降低，促运动表型丧失。最后，为了阐明LOX调节肌动蛋白聚合的机制，我们证明LOX促进p130（Cas）磷酸化，这允许其与CAS相关激酶（Crk）结合并形成p130（Cas）/Crk/DOCK180信号复合物。该复合物的形成导致Rac-GTP增加，从而减少肌动蛋白应激纤维的形成并增加片状伪足的形成。这些数据表明，LOX通过肌动蛋白丝聚合的变化来调节细胞运动性/迁移，这涉及对p130（Cas）/Crk/DOCK180信号通路的调节。阐明LOX在调节细胞运动性中的作用将有助于开发更有效的治疗策略来治疗侵袭性/转移性乳腺癌。
