Raylman R R, Clavo A C, Wahl R L
University of Michigan Medical Center, Department of Internal Medicine, Ann Arbor, USA.
Bioelectromagnetics. 1996;17(5):358-63. doi: 10.1002/(SICI)1521-186X(1996)17:5<358::AID-BEM2>3.0.CO;2-2.
Proposals to enhance the amount of radiation dose delivered to small tumors with radioimmunotherapy by constraining emitted electrons with very strong homogeneous static magnetic fields has renewed interest in the cellular effects of prolonged exposures to such fields. Past investigations have not studied the effects on tumor cell growth of lengthy exposures to very high magnetic fields. Three malignant human cell lines, HTB 63 (melanoma), HTB 77 IP3 (ovarian carcinoma), and CCL 86 (lymphoma: Raji cells), were exposed to a 7 Tesla uniform static magnetic field for 64 hours. Following exposure, the number of viable cells in each group was determined. In addition, multicycle flow cytometry was performed on all cell lines, and pulsed-field electrophoresis was performed solely on Raji cells to investigate changes in cell cycle patterns and the possibility of DNA fragmentation induced by the magnetic field. A 64 h exposure to the magnetic field produced a reduction in viable cell number in each of the three cell lines. Reductions of 19.04 +/- 7.32%, 22.06 +/- 6.19%, and 40.68 +/- 8.31% were measured for the melanoma, ovarian carcinoma, and lymphoma cell lines, respectively, vs. control groups not exposed to the magnetic field. Multicycle flow cytometry revealed that the cell cycle was largely unaltered. Pulsed-field electrophoresis analysis revealed no increase in DNA breaks related to magnetic field exposure. In conclusion, prolonged exposure to a very strong magnetic field appeared to inhibit the growth of three human tumor cell lines in vitro. The mechanism underlying this effect has not, as yet, been identified, although alteration of cell growth cycle and gross fragmentation of DNA have been excluded as possible contributory factors. Future investigations of this phenomenon may have a significant impact on the future understanding and treatment of cancer.
通过用非常强的均匀静磁场约束发射的电子来提高放射免疫疗法传递到小肿瘤的辐射剂量的提议，重新引发了人们对长时间暴露于此类磁场的细胞效应的兴趣。过去的研究尚未探讨长时间暴露于非常高磁场对肿瘤细胞生长的影响。将三种恶性人类细胞系，即HTB 63（黑色素瘤）、HTB 77 IP3（卵巢癌）和CCL 86（淋巴瘤：Raji细胞）暴露于7特斯拉的均匀静磁场中64小时。暴露后，测定每组中的活细胞数量。此外，对所有细胞系进行多周期流式细胞术，仅对Raji细胞进行脉冲场电泳，以研究细胞周期模式的变化以及磁场诱导DNA片段化的可能性。暴露于磁场64小时导致三种细胞系中的活细胞数量均减少。与未暴露于磁场的对照组相比，黑色素瘤、卵巢癌和淋巴瘤细胞系的减少率分别为19.04±7.32%、22.06±6.19%和40.68±8.31%。多周期流式细胞术显示细胞周期基本未改变。脉冲场电泳分析显示与磁场暴露相关的DNA断裂没有增加。总之，长时间暴露于非常强的磁场似乎在体外抑制了三种人类肿瘤细胞系的生长。尽管细胞生长周期的改变和DNA的严重片段化已被排除为可能的促成因素，但这种效应的潜在机制尚未确定。对这一现象的未来研究可能会对癌症的未来理解和治疗产生重大影响。
