• 30 MAR 10
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    #1234: New study finds low level EMFs reduce melatonin’s protective effect

    From Cindy Sage on the CHE-EMF list:

    EMF at only 12 mG has been shown to reduce the protective effect of melatonin on human breast cancer cells. This is the latest in a series of at least seven (7) papers reporting similar results. These EMF (magnetic field) levels of exposure can be found in homes and offices near transmission lines or with faulty wiring, or near large electrical appliances or electric panels. 1.2 uT (microTesla) is the same as 12 milligauss (12 mG).

    Cindy Sage
    CHE-EMF

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    Girgert, R Hanf V Emons G Grundker, 2010. Signal Transduction of the Melatonin Receptor
    MT1Is Disrupted in Breast Cancer Cells by Electromagnetic Fields. Bioelectromagnetics 31:237- 245 (2010)

    Abstract

    The growth of estrogen-receptor positive breast cancer cells is inhibited by the pineal gland hormone, melatonin. Concern has been raised that power-line frequency and microwave electromagnetic fields
    (EMFs) could reduce the efficiency of melatonin on breast cancer cells. In this study we investigated the impact of EMFs on the signal transduction of the high-affinity receptor MT1 in parental MCF-7 cells and MCF-7 cells transfected with the MT1 gene. The binding of the cAMP-responsive element binding (CREB) protein to a promoter sequence of BRCA-1 after stimulation with melatonin was analyzed by a gel-shift assay and the expression of four estrogen-responsive genes was measured in sham-exposed breast cancer cells and cells exposed to a sinusoidal 50 Hz EMF of 1.2 uT for 48 h. In sham-exposed cells, binding of CREB to the promoter of BRCA-1 was increased by estradiol and subsequently diminished by treatment with melatonin. In cells exposed to 1.2 uT, 50 Hz EMF, binding of CREB was almost completely omitted. Expression of BRCA-1, p53, p21WAF, and c-myc was increased by estradiol stimulation and subsequently decreased by melatonin treatment in both cell lines, except for p53 expression in the transfected cell line, thereby proving the antiestrogenic effect of melatonin at molecular level. In contrast, in breast cancer cells transfected withMT1exposed to 1.2 uT of the 50 Hz EMF, the expression of p53 and c-myc increased significantly after melatonin treatment but for p21WAF the increase was not significant. These results convincingly prove the negative effect of EMF on the antiestrogenic effect of melatonin in breast cancer cells. Bioelectromagnetics 31:237–245, 2010. 2009 Wiley-Liss, Inc.

    Key words: breast cancer; electromagnetic fields

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    The BioInitiative Report, Chapter 13, Evidence for Breast Cancer Promotion (2007) summarizes earlier studies. Note that the author of this paper – Girgert – also published on the negative effect of EMF on tamoxifen. Please contact Cindy Sage if you would like copies of any of these articles.

    II. Melatonin and ELF-EMF

    Evidence which supports a possible mechanism for ELF-EMF and breast cancer is the consistent finding (in five separate labs) that environmental levels of ELF-EMF can act at the cellular level to enhance breast cancer proliferation by blocking melatonin’s natural oncostatic action in MCF-7 cells (Liburdy, 1993; Luben et al, 1996; Morris et al, 1998; Blackman et al, 2001; Ishido, et al, 2001). ELF-EMF levels between 0.6 and 1.2 µT have been shown to consistently block the protective effects of melatonin.

    The series of papers reporting increased breast cancer cell proliferation when ELF-EMF at environmental levels negatively affects the oncostatic actions of melatonin in MCF-7 cells should warrant new public exposure guidelines or planning target limits for the public, and for various susceptible segments of the population.

    References

    Liburdy, R. P., T. R. Sloma, et al, 1993. ELF magnetic fields, breast cancer, andmelatonin: 60 Hz fields block melatonin’s oncostatic action on ER+ breast cancer cell proliferation. J of Pineal Research. 14: 89-97.

    Luben et al, 1996. Replication of 12 mG EMF effects on melatonin responses of MCF-7 breast cancer cells in vitro. Abstract A-1 of the 1996 Annual review of research on biological effects of electric and magnetic fields from the generation, delivery and use of electricity, November 17-21, 1996. San Antonio, Texas, p.1

    Luben et al, 1998. Independent replication of 60-Hz 1.2 µT EMF effects on melatonin and tamoxifen responses of MCF-7 cells in vitro. Abstract A-3.4, Bioelectromagnetics Society Annual Meeting, St. Pete Beach, FL. June 7-11, p 17-18.

    Morris et al, 1998. In vitro exposure of MCF-7 human breast cancer cells to 60-Hz magnetic fields. Abstract p-125A, Bioelectromagnetics Society Annual Meeting, St. Pete Beach, FL. June 7-11, p 204-205.

    Ishido et al, 2001. Magnetic fields (MF) of 50 Hz at 1.2 µT as well as 100 µT cause uncoupling of inhibitory pathways of adenylyl cyclase mediated by melatonin 1a receptor in MF-sensitive MCF-7 cells.

    D.E. Blask, S.M. Hill, Effects of melatonin on cancer: studies on MCF-7 human breast cancer cells in culture, J. Neural Transm. Suppl. 21 (1986) 433–449.

    Loberg LI et al 1999. Gene expression in human breast epithelial cells exposed to 60 Hz magnetic fields, Carcinogenesis 20 1633–1636.

    III. Tamoxifen and ELF-EMF

    Girgert et al (2005) reported that “the anti-estrogenic activity of tamoxifen is reduced in two subclones of MCF-7 cells under the influence of ELF/EMF to different extent. Dose-response curves of the growth-inhibitory effect of tamoxifen are shifted towards higher concentrations leading to a reduced growth inhibition at a given concentration. Our observations confirm results from a previous report describing a reduced inhibitory effect of tamoxifen at 1—7 M from 40% to only 17% by exposure to an EMF of 1.2 µT” (Harland t al, 1997). Further, Girgert et al conclude that “From a medical point of view, it is disturbing that maximal induction of cell proliferation by tamoxifen at a field strength of 1.2 µT is observed at concentration of 10-6 M. This is exactly the serum concentration achieved in BC patients under standard oral therapy.” (De Cupis et al, 1997).

    The Girgert et al paper confirms prior findings that environmental level ELF-EMF inhibits the antiproliferative action of tamoxifen in MCF-7 human breast cancer cells. Four other papers reporting this effect include Liburdy et al, 1997; Harland et al, 1997; Harland et al, 1999; and Blackman et al, 2001).
    References

    Liburdy et al, 1997. Magnetic Fields, Melatonin, Tamoxifen, and Human Breast Cancer Cell Growth. In: Stevens R. G., Wilson B. W., Anderson L.E. (Eds). The Melatonin Hypothesis – Breast Cancer and Use of Electric Power. Battelle Press, Columbus, Richland 1997: 669- 700.

    Harland et al, 1997. Environmental magnetic fields inhibit the antiproliferative action of tamoxifen and melatonin in a human breast cancer cell line. Bioelectromagnetics, 18, 555-562.

    Harland et al, 1999. Evidence for a slow time-scale of interaction for magnetic fields inhibiting tamoxifen’s antiproliferative action in human breast cancer cells. Cell Biochemistry & Biophysics, 31(3), 295-306.

    Blackman et al, 2001. The influence of 1.2 μT, 60 Hz magnetic fields on melatonin and tamoxifen-induced inhibition of MCF-7 cell growth. Bioelectromagnetics, 22(2), 122-128.

    Girgert et al, 2005. Induction of tamoxifen resistance in breast cancer cells by ELF electromagnetic fields. Biochemical & Biophysics Research Communications, 336, 1144-1149.

    A. De Cupis et al, 1997. Oestrogen/growth factor cross-talk in breast carcinoma: a specific target for novel antioestrogens, TIPS 18 245–251.

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