Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada.
Phys Med Biol. 2013 Feb 21;58(4):923-36. doi: 10.1088/0031-9155/58/4/923. Epub 2013 Jan 22.
Evidence suggests that compression and shear wave elastography are sensitive to the mechanical property changes occuring in dying cells following chemotherapy, and can hence be used to monitor cancer treatment response. A qualitative and quantitative understanding of the mechanical changes at the cellular level would allow to better infer how these changes affect macroscopic tissue mechanical properties and therefore allow the optimization of elastographic techniques (such as shear wave elastography) for the monitoring of cancer therapy. We used intracellular particle tracking microrheology (PTM) to investigate the mechanical property changes of cells exposed to paclitaxol, a mitotic inhibitor used in cancer chemotherapy. The average elastic and viscous moduli of the cytoplasm of treated MCF-7 breast cancer cells were calculated for frequency ranges between 0.2 and 100 rad s(-1) (corresponding to 0.03 and 15.92 Hz, respectively). A significant increase in the complex shear modulus of the cell cytoplasm was detected at 12 h post treatment. At 24 h after drug exposure, the elastic and viscous moduli increased by a total of 191.3 Pa (>8000×) and 9 Pa (∼9×), respectively for low frequency shear modulus measurements (at 1 rad s(-1)). At higher frequencies (10 rad s(-1)), the elastic and viscous moduli increased by 188.5 Pa (∼60×) and 1.7 Pa (∼1.1×), respectively. Our work demonstrates that PTM can be used to measure changes in the mechanical properties of treated cells and that cell elasticity significantly increases by 24 h after chemotherapy exposure.
有证据表明，压缩和剪切波弹性成像对化疗后细胞死亡过程中机械性能的变化敏感，因此可用于监测癌症治疗反应。在细胞水平上对机械变化进行定性和定量理解，将有助于更好地推断这些变化如何影响宏观组织的机械性能，并因此优化弹性成像技术（如剪切波弹性成像）以监测癌症治疗。我们使用细胞内颗粒跟踪微流变学（PTM）来研究暴露于紫杉醇（一种用于癌症化疗的有丝分裂抑制剂）的细胞的机械性能变化。对于频率范围在 0.2 到 100 rad s(-1)（分别对应于 0.03 和 15.92 Hz）之间的处理 MCF-7 乳腺癌细胞的细胞质的平均弹性和粘性模量进行了计算。在治疗后 12 小时检测到细胞质的复剪切模量显著增加。在药物暴露 24 小时后，低频剪切模量测量（在 1 rad s(-1))时，弹性和粘性模量总共增加了 191.3 Pa（>8000×）和 9 Pa（∼9×）。在较高频率（10 rad s(-1))时，弹性和粘性模量分别增加了 188.5 Pa（∼60×）和 1.7 Pa（∼1.1×）。我们的工作表明，PTM 可用于测量处理细胞的机械性能变化，并且在化疗暴露后 24 小时细胞弹性显著增加。
