Biological Physics Division, Institute of Experimental Physics I, Faculty of Physics and Earth Science, University of Leipzig, Leipzig, Germany.
Cell Biochem Biophys. 2013 Jul;66(3):599-622. doi: 10.1007/s12013-012-9506-3.
Cell invasion through the extracellular matrix (ECM) of connective tissue is an important biomechanical process, which plays a prominent role in tumor progression. The malignancy of tumors depends mainly on the capacity of cancer cells to migrate and metastasize. A prerequisite for metastasis is the invasion of cancer cells through connective tissue to targeted organs. Cellular stiffness and cytoskeletal remodeling dynamics have been proposed to affect the invasiveness of cancer cells. Here, this study investigated whether highly invasive cancer cells are capable of invading into dense 3D-ECMs with an average pore-size of 1.3 or 3.0 μm when phagocytized beads (2.7 and 4.5 μm diameter) increased their cellular stiffness and reduced their cytoskeletal remodeling dynamics compared to weakly invasive cancer cells. The phagocytized beads decreased the invasiveness of the α5β1(high) cancer cells into 3D-ECMs, whereas the invasiveness of the α5β1(low) cancer cells was not affected. The effect of phagocytized beads on the highly invasive α5β1(high) cells was abolished by specific knock-down of the α5 integrin subunit or addition of an anti-α5 integrin blocking antibody. Furthermore, the reduction of contractile forces using MLCK and ROCK inhibitors abolished the effect of phagocytized beads on the invasiveness of α5β1(high) cells. In addition, the cellular stiffness of α5β1(high) cells was increased after bead phagocytosis, whereas the bead phagocytosis did not alter the stiffness of α5β1(low) cells. Taken together, the α5β1 integrin dependent invasiveness was reduced after bead phagocytosis by altered biomechanical properties, suggesting that the α5β1(high) cells need an appropriate intermediate cellular stiffness to overcome the steric hindrance of 3D-ECMs, whereas the α5β1(low) cells were not affected by phagocytized beads.
细胞穿过细胞外基质（ECM）侵入结缔组织是一个重要的生物力学过程，在肿瘤进展中起着突出的作用。肿瘤的恶性程度主要取决于癌细胞迁移和转移的能力。转移的一个前提是癌细胞穿过结缔组织到达靶向器官。细胞硬度和细胞骨架重塑动力学已被提出影响癌细胞的侵袭性。在这里，本研究调查了高度侵袭性的癌细胞在吞噬珠（直径为 2.7 和 4.5μm）增加细胞硬度并减少细胞骨架重塑动力学时，是否能够侵入平均孔径为 1.3 或 3.0μm 的致密 3D-ECM。与弱侵袭性癌细胞相比，吞噬珠降低了α5β1（高）癌细胞对 3D-ECM 的侵袭性，而α5β1（低）癌细胞的侵袭性不受影响。通过特异性敲低α5 整合素亚基或添加抗α5 整合素阻断抗体，吞噬珠对高度侵袭性的α5β1（高）细胞的作用被消除。此外，使用 MLCK 和 ROCK 抑制剂降低收缩力消除了吞噬珠对α5β1（高）细胞侵袭性的影响。此外，α5β1（高）细胞吞噬珠后细胞硬度增加，而吞噬珠对α5β1（低）细胞的硬度没有影响。总之，α5β1 整合素依赖性侵袭性在吞噬珠后由于生物力学特性的改变而降低，表明α5β1（高）细胞需要适当的中间细胞硬度来克服 3D-ECM 的空间障碍，而α5β1（低）细胞不受吞噬珠的影响。
