Department of Molecular Biology and Genetics, Democritus University of Thrace, 68100 Alexandroupolis, Greece.
Nanotechnology. 2018 Apr 27;29(17):175101. doi: 10.1088/1361-6528/aaaea9. Epub 2018 Mar 2.
Recent investigations have attempted to understand and exploit the impact of magnetic field-actuated internalized magnetic nanoparticles (MNPs) on the proliferation rate of cancer cells. Due to the complexity of the parameters governing magnetic field-exposure though, individual studies to date have raised contradictory results. In our approach we performed a comparative analysis of key parameters related to the cell exposure of cancer cells to magnetic field-actuated MNPs, and to the magnetic field, in order to better understand the factors affecting cellular responses to magnetic field-stimulated MNPs. We used magnetite MNPs with a hydrodynamic diameter of 100 nm and studied the proliferation rate of MNPs-treated versus untreated HT29 human colon cancer cells, exposed to either static or alternating low frequency magnetic fields with varying intensity (40-200 mT), frequency (0-8 Hz) and field gradient. All three parameters, field intensity, frequency, and field gradient affected the growth rate of cells, with or without internalized MNPs, as compared to control MNPs-untreated and magnetic field-untreated cells. We observed that the growth inhibitory effects induced by static and rotating magnetic fields were enhanced by pre-treating the cells with MNPs, while the growth promoting effects observed in alternating field-treated cells were weakened by MNPs. Compared to static, rotating magnetic fields of the same intensity induced a similar extend of cell growth inhibition, while alternating fields of varying intensity (70 or 100 mT) and frequency (0, 4 or 8 Hz) induced cell proliferation in a frequency-dependent manner. These results, highlighting the diverse effects of mode, intensity, and frequency of the magnetic field on cell growth, indicate that consistent and reproducible results can be achieved by controlling the complexity of the exposure of biological samples to MNPs and external magnetic fields, through monitoring crucial experimental parameters. We demonstrate that further research focusing on the accurate manipulation of the aforementioned magnetic field exposure parameters could lead to the development of successful non-invasive therapeutic anticancer approaches.
最近的研究试图理解和利用磁场驱动的内吞磁性纳米粒子（MNPs）对癌细胞增殖率的影响。由于目前为止，单独的研究对控制磁场暴露的参数的复杂性，提出了相互矛盾的结果。在我们的方法中，我们对与癌症细胞暴露于磁场驱动的 MNPs 相关的关键参数进行了比较分析，以及磁场，以便更好地理解影响细胞对磁场刺激的 MNPs 的反应的因素。我们使用了水动力学直径为 100nm 的磁铁矿 MNPs，并研究了 MNPs 处理的 HT29 人结肠癌细胞与未处理的 HT29 人结肠癌细胞的增殖率，这些细胞分别暴露于不同强度（40-200mT）、频率（0-8Hz）和梯度的静态或交变低频磁场。所有三个参数，磁场强度、频率和梯度都影响着有或没有内吞 MNPs 的细胞的生长速度，与未处理 MNPs 的对照细胞和未处理磁场的细胞相比。我们观察到，与未处理 MNPs 的对照细胞和未处理磁场的细胞相比，静磁场和旋转磁场诱导的生长抑制作用可以通过预先用 MNPs 处理细胞来增强，而交变磁场处理的细胞中观察到的促进生长作用可以通过 MNPs 来减弱。与静磁场相比，相同强度的旋转磁场会引起类似程度的细胞生长抑制，而不同强度（70 或 100mT）和频率（0、4 或 8Hz）的交变磁场会以频率依赖的方式诱导细胞增殖。这些结果突出了磁场的模式、强度和频率对细胞生长的不同影响，表明通过控制生物样本暴露于 MNPs 和外磁场的复杂性，可以通过监测关键的实验参数来获得一致和可重复的结果。我们证明，进一步研究集中于精确控制上述磁场暴露参数，可以导致发展成功的非侵入性治疗抗癌方法。
