Ravin Rea, Cai Teddy X, Li Aiguo, Briceno Nicole, Pursley Randall H, Garmendia-Cedillos Marcial, Pohida Tom, Wang Herui, Zhuang Zhengping, Cui Jing, Morgan Nicole Y, Williamson Nathan H, Gilbert Mark R, Basser Peter J
Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH Bethesda, Maryland, USA.
Celoptics, Inc. Rockville, Maryland, USA.
Am J Cancer Res. 2024 Feb 15;14(2):562-584. doi: 10.62347/NDII9862. eCollection 2024.
Previous studies reported that alternating electric fields (EFs) in the intermediate frequency (100-300 kHz) and low intensity (1-3 V/cm) regime - termed "Tumor Treating Fields" (TTFields) - have a specific, anti-proliferative effect on glioblastoma multiforme (GBM) cells. However, the mechanism(s) of action remain(s) incompletely understood, hindering the clinical adoption of treatments based on TTFields. To advance the study of such treatment , we developed an inductive device to deliver EFs to cell cultures which improves thermal and osmolar regulation compared to prior devices. Using this inductive device, we applied continuous, 200 kHz electromagnetic fields (EMFs) with a radial EF amplitude profile spanning 0-6.5 V/cm to cultures of primary rat astrocytes and several human GBM cell lines - U87, U118, GSC827, and GSC923 - for a duration of 72 hours. Cell density was assessed via segmented pixel densities from GFP expression (U87, U118) or from staining (astrocytes, GSC827, GSC923). Further RNA-Seq analyses were performed on GSC827 and GSC923 cells. Treated cultures of all cell lines exhibited little to no change in proliferation at lower EF amplitudes (0-3 V/cm). At higher amplitudes (> 4 V/cm), different effects were observed. Apparent cell densities increased (U87), decreased (GSC827, GSC923), or showed little change (U118, astrocytes). RNA-Seq analyses on treated and untreated GSC827 and GSC923 cells revealed differentially expressed gene sets of interest, such as those related to cell cycle control. Up- and down-regulation, however, was not consistent across cell lines nor EF amplitudes. Our results indicate no consistent, anti-proliferative effect of 200 kHz EMFs across GBM cell lines and thus contradict previous findings. Rather, effects varied across different cell lines and EF amplitude regimes, highlighting the need to assess the effect(s) of TTFields and similar treatments on a per cell line basis.
先前的研究报道，处于中频（100 - 300千赫兹）和低强度（1 - 3伏/厘米）范围的交变电场（EFs）——被称为“肿瘤治疗电场”（TTFields）——对多形性胶质母细胞瘤（GBM）细胞具有特定的抗增殖作用。然而，其作用机制仍未完全明确，这阻碍了基于TTFields的治疗方法在临床上的应用。为了推进此类治疗的研究，我们开发了一种感应装置，用于向细胞培养物输送电场，与先前的装置相比，该装置改善了热调节和渗透压调节。使用这种感应装置，我们对原代大鼠星形胶质细胞和几种人类GBM细胞系——U87、U118、GSC827和GSC923——施加了连续的、200千赫兹的电磁场（EMFs），其径向电场强度分布范围为0 - 6.5伏/厘米，持续72小时。通过绿色荧光蛋白（GFP）表达（U87、U118）或染色（星形胶质细胞、GSC827、GSC923）的分割像素密度来评估细胞密度。对GSC827和GSC923细胞进行了进一步的RNA测序分析。在较低电场强度（0 - 3伏/厘米）下，所有细胞系的处理培养物增殖几乎没有变化或没有变化。在较高电场强度（> 4伏/厘米）下，观察到了不同的效应。明显的细胞密度增加（U87）、减少（GSC827、GSC923）或几乎没有变化（U118、星形胶质细胞）。对处理和未处理的GSC827和GSC923细胞进行的RNA测序分析揭示了一些感兴趣的差异表达基因集，例如与细胞周期控制相关的基因集。然而，上调和下调在不同细胞系和电场强度之间并不一致。我们的结果表明，200千赫兹的电磁场对GBM细胞系没有一致的抗增殖作用，因此与先前的研究结果相矛盾。相反，效应在不同细胞系和电场强度范围内有所不同，这突出表明需要针对每个细胞系评估TTFields及类似治疗的效果。
