Liburdy R P, Sloma T R, Sokolic R, Yaswen P
Department of Cell and Molecular Biology, Life Sciences Division, Lawrence Berkeley Laboratory, UC Berkeley, CA 94720.
J Pineal Res. 1993 Mar;14(2):89-97. doi: 10.1111/j.1600-079x.1993.tb00491.x.
In this study we investigated whether a 60 Hz magnetic field can act at the cellular level to influence the growth of human estrogen-dependent breast cancer cells. Our experimental design assessed cell proliferation of a human breast cancer cell line, MCF-7, in the absence or the presence of melatonin which inhibits growth at a physiological concentration of 10(-9) M. In three experiments, continuous exposure to average sinusoidal 60 Hz magnetic fields of 1.90 +/- 0.01, 2.40 +/- 0.70, and 2.53 +/- 0.50 mG, or simultaneous exposure in matched incubators to average 60 Hz magnetic fields of 10.4 +/- 2.12, 11.95 +/- 2.73, and 11.95 +/- 3.28 mG, respectively, had no effect on cell proliferation in the absence of melatonin. When MCF-7 cells were cultured in the presence of 10(-9) M melatonin, an 18% inhibition of growth was observed for cells in a 2.40 +/- 0.70 mG field. This effect was blocked by a 60 Hz magnetic field of 11.95 +/- 2.75 mG. In a second experiment, a 27% inhibition of MCF-7 cell growth was observed for cells in a 2.53 +/- 0.50 mG magnetic field, and this was blocked by a 60 Hz magnetic field of 11.95 +/- 3.28 mG. These results provide the first evidence that ELF frequency magnetic fields can act at the cellular levels to enhance breast cancer cell proliferation by blocking melatonin's natural oncostatic action. In addition, there appears to be a dose threshold between 2 and 12 mG. The mechanism(s) of action is unknown and may involve modulation of signal transduction events associated with melatonin's regulation of cell growth.
在本研究中，我们调查了60赫兹的磁场是否能在细胞水平上影响人类雌激素依赖性乳腺癌细胞的生长。我们的实验设计评估了人乳腺癌细胞系MCF - 7在不存在或存在褪黑素（在10(-9) M的生理浓度下抑制生长）时的细胞增殖情况。在三个实验中，持续暴露于平均正弦60赫兹、强度分别为1.90±0.01、2.40±0.70和2.53±0.50毫高斯的磁场中，或在匹配的培养箱中同时暴露于平均60赫兹、强度分别为10.4±2.12、11.95±2.73和11.95±3.28毫高斯的磁场中，在不存在褪黑素的情况下对细胞增殖均无影响。当MCF - 7细胞在10(-9) M褪黑素存在的情况下培养时，在强度为2.40±0.70毫高斯的磁场中观察到细胞生长受到18%的抑制。这种效应被强度为11.95±2.75毫高斯的60赫兹磁场阻断。在第二个实验中，在强度为2.53±0.50毫高斯的磁场中观察到MCF - 7细胞生长受到27%的抑制，并且这被强度为11.95±3.28毫高斯的60赫兹磁场阻断。这些结果提供了首个证据，表明极低频磁场可在细胞水平上通过阻断褪黑素的天然抑癌作用来增强乳腺癌细胞增殖。此外，似乎在2至12毫高斯之间存在剂量阈值。作用机制尚不清楚，可能涉及与褪黑素对细胞生长调节相关的信号转导事件的调节。
