A 60-Hz sinusoidal magnetic field induces apoptosis of prostate cancer cells through reactive oxygen species

Anti-tumor effect of innovative tumor treatment device OM-100 through enhancing anti-PD-1 immunotherapy in glioblastoma growth

Glioblastoma (GBM) is associated with a median survival rate of less than 15 months, necessitating innovative treatment approaches. This study investigates the safety and efficacy of the low-frequency magnetic field (LFMF) OM-100 instrument in GBM therapy. In vitro experiments utilized normal astrocyte and GBM cell lines, determining that OM-100 at 100 kHz for 72 h selectively targeted GBM cells without harming normal cells. Subsequent analyses revealed OM-100's impact on cell viability, apoptosis, migration, invasion, reactive oxide species levels, and PD-L1 expression. In vivo studies on mice with U87-induced GBM demonstrated OM-100's synergy with anti-PD-1 therapy, leading to significant tumor volume reduction and increased apoptosis. Notably, OM-100 exhibited safety in healthy mice. Overall, OM-100 could enhance anti-PD-1 immunotherapy effectiveness probably by directly inhibiting tumor proliferation and migration as well as promoting PD-L1 expression, offering a promising therapeutic strategy for GBM treatment.

Low-frequency magnetic field therapy for glioblastoma: Current advances, mechanisms, challenges and future perspectives

BACKGROUND

Glioblastoma (GBM) is the most common malignant tumour of the central nervous system. Despite recent advances in multimodal GBM therapy incorporating surgery, radiotherapy, systemic therapy (chemotherapy, targeted therapy), and supportive care, the overall survival (OS) remains poor, and long-term survival is rare. Currently, the primary obstacles hindering the effectiveness of GBM treatment are still the blood-brain barrier and tumor heterogeneity. In light of its substantial advantages over conventional therapies, such as strong penetrative ability and minimal side effects, low-frequency magnetic fields (LF-MFs) therapy has gradually caught the attention of scientists.

AIM OF REVIEW

In this review, we shed the light on the current status of applying LF-MFs in the treatment of GBM. We specifically emphasize our current understanding of the mechanisms by which LF-MFs mediate anticancer effects and the challenges faced by LF-MFs in treating GBM cells. Furthermore, we discuss the prospective applications of magnetic field therapy in the future treatment of GBM. Key scientific concepts of review: The review explores the current progress on the use of LF-MFs in the treatment of GBM with a special focus on the potential underlying mechanisms of LF-MFs in anticancer effects. Additionally, we also discussed the complex magnetic field features and biological characteristics related to magnetic bioeffects. Finally, we proposed a promising magnetic field treatment strategy for future applications in GBM therapy.

The Application of Electromagnetic Fields in Cancer

The use of nonionizing electromagnetic fields (EMFs) has attracted interest in cancer research during the past few decades due to its noninvasive therapeutic successes in the treatment of cancer. Some epidemiological studies suggest that there may be a link between exposure to EMF and developing malignancies (such as leukemia and gliomas) or neurodegenerative diseases since EMF has a variety of biological effects such as altering reactive oxygen species (ROS)-regulated pathways. EMF exposure, however, has the potential to cause cancer cells to undergo a period of regulated cell death. Therefore, it is important to thoroughly investigate how EMF might influence cellular processes such as proliferation, differentiation, and apoptosis - processes that are targeted in cancer treatment. In this chapter, we give a thorough summary of the most recent studies on the potential use of various EMF applications with adjustable settings to treat different forms of cancer.

Glycocalyx transduces membrane leak in brain tumor cells exposed to sharp magnetic pulsing

Mechanisms by which electric (E) or magnetic (B) fields might be harnessed to affect tumor cell behavior remain poorly defined, presenting a barrier to translation. We hypothesized in early studies that the glycocalyx of lung cancer cells might play a role in mediating plasma membrane leak by low-frequency pulsed magnetic fields (Lf-PMF) generated on a low-energy solenoid platform. In testing glioblastoma and neuroblastoma cells known to overexpress glycoproteins rich in modifications by the anionic glycan sialic acid (Sia), exposure of brain tumor cells on the same platform to a pulse train that included a 5 min 50Hz Lf-PMF (dB/dt ∼ 2 T/s at 10 ms pulse widths) induced a very modest but significant protease leak above that of control nonexposed cells (with modest but significant reductions in long-term tumor cell viability after the 5 min exposure). Using a markedly higher dB/dt system (80 T/s pulses, 70 μs pulse-width at 5.9 cm from a MagVenture coil source) induced markedly greater leak by the same cells, and eliminating Sia by treating cells with AUS sialidase immediately preexposure abrogated the effect entirely in SH-SY5Y neuroblastoma cells, and partially in T98G glioblastoma cells. The system demonstrated significant leak (including inward leak of propidium iodide), with reduced leak at lower dB/dt in a variety of tumor cells. The ability to abrogate Lf-PMF protease leak by pretreatment with sialidase in SH-SY5Y brain tumor cells or with heparin lyase in A549 lung tumor cells indicated the importance of heavy Sia or heparan sulfate glycosaminoglycan glycocalyx modifications as dominant glycan species mediating Lf-PMF membrane leak in respective tumor cells. This "first-physical" Lf-PMF tumor glycocalyx event, with downstream cell stress, may represent a critical and "tunable" transduction mechanism that depends on characteristic anionic glycans overexpressed by distinct malignant tumors.

Spinning magnetic field patterns that cause oncolysis by oxidative stress in glioma cells

Raising reactive oxygen species (ROS) levels in cancer cells to cause macromolecular damage and cell death is a promising anticancer treatment strategy. Observations that electromagnetic fields (EMF) elevate intracellular ROS and cause cancer cell death, have led us to develop a new portable wearable EMF device that generates spinning oscillating magnetic fields (sOMF) to selectively kill cancer cells while sparing normal cells in vitro and to shrink GBM tumors in vivo through a novel mechanism. Here, we characterized the precise configurations and timings of sOMF stimulation that produce cytotoxicity due to a critical rise in superoxide in two types of human glioma cells. We also found that the antioxidant Trolox reverses the cytotoxic effect of sOMF on glioma cells indicating that ROS play a causal role in producing the effect. Our findings clarify the link between the physics of magnetic stimulation and its mechanism of anticancer action, facilitating the development of a potential new safe noninvasive device-based treatment for GBM and other gliomas.

Three-Dimensional Gene Regulation Network in Glioblastoma Ferroptosis

Ferroptosis is an iron-dependent form of cell death, which is reported to be associated with glioma progression and drug sensitivity. Targeting ferroptosis is a potential therapeutic approach for glioma. However, the molecular mechanism of glioma cell ferroptosis is not clear. In this study, we profile the change of 3D chromatin structure in glioblastoma ferroptosis by using HiChIP and study the 3D gene regulation network in glioblastoma ferroptosis. A combination of an analysis of HiChIP and RNA-seq data suggests that change of chromatin loops mediated by 3D chromatin structure regulates gene expressions in glioblastoma ferroptosis. Genes that are regulated by 3D chromatin structures include genes that were reported to function in ferroptosis, like HDM2 and TXNRD1. We propose a new regulatory mechanism governing glioblastoma cell ferroptosis by 3D chromatin structure.

System-level biological effects of extremely low-frequency electromagnetic fields: an in vivo experimental review

During the past decades, the potential effects of extremely low-frequency electromagnetic fields (ELF-EMFs) on human health have gained great interest all around the world. Though the International Commission on Non-Ionizing Radiation Protection recommended a 100 μT, and then a 200 μT magnetic field limit, the long-term effects of ELF-EMFs on organisms and systems need to be further investigated. It was reported that both electrotherapy and possible effects on human health could be induced under ELF-EM radiation with varied EM frequencies and fields. This present article intends to systematically review the in vivo experimental outcome and the corresponding mechanisms to shed some light on the safety considerations of ELF-EMFs. This will further advance the subsequent application of electrotherapy in human health.

P53 status, and G2/M cell cycle arrest, are determining factors in cell-death induction mediated by ELF-EMF in glioblastoma

The average survival of patients with glioblastoma is 12-15 months. Therefore, finding a new treatment method is important, especially in cases that show resistance to treatment. Extremely low-frequency electromagnetic fields (ELF-EMF) have characteristics and capabilities that can be proposed as a new cancer treatment method with low side effects. This research examines the antitumor effect of ELF-EMF on U87 and U251 glioblastoma cell lines. Flowcytometry determined the viability/apoptosis and distribution of cells in different phases of the cell cycle. The size of cells was assessed by TEM. Important cell cycle regulation genes mRNA expression levels were investigated by real-time PCR. ELF-EMF induced apoptosis in U87cells much more than U251 (15% against 2.43%) and increased G2/M cell population in U87 (2.56%, p value < 0.05), and S phase in U251 (2.4%) (data are normalized to their sham exposure). The size of U87 cells increased significantly after ELF-EMF exposure (overexpressing P53 in U251 cells increased the apoptosis induction by ELF-EMF). The expression level of P53, P21, and MDM2 increased and CCNB1 decreased in U87. Among the studied genes, MCM6 expression decreased in U251. Increasing expression of P53, P21 and decreasing CCNB1, induction of cell G2/M cycle arrest, and consequently increase in the cell size can be suggested as one of the main mechanisms of apoptosis induction by ELF-EMF; furthermore, our results demonstrate the possible footprint of P53 in the apoptosis induction by ELF-EMF, as U87 carry the wild type of P53 and U251 has the mutated form of this gene.

Effects of extremely low frequency electromagnetic fields on the tumor cell inhibition and the possible mechanism

Low-frequency magnetic fields exert a significant inhibitory effect on tumor growth and have been developed as a therapeutic modality. However, the effect of a low-frequency magnetic field on the interaction between cells is still poorly understood. This study aimed to preliminarily evaluate the direct effect of magnetic field ditectely on cultured cells and indirect effect mediated by cell-environment (conditioned medium). 293 T cells, Hepg2 cells, A549 cells have been cultured at 37 ± 0.18 °C in presence of an extremely low-frequency magnetic field of 20 Hz, 5-mT. The adherent tumor cells were more sensitive to magnetic field inhibition in the original environment (conditioned medium) with adherence inhibition rate for Hepg2 and A549 estimated at 18% and 30% respectively. The inhibition effect was suppressed when the suspended cells separated or clump density at a low density. The nontumor cell lines showed no inhibitory effect on exposure to a low-frequency magnetic field. The intracellular ion fluorescence (IIF) showed that the magnetic field significantly altered the membrane potential, indicating hyperpolarization of the adherent cells (ΔIIF 293 T cells: - 25%, ΔIIF Hepg2 cells: - 20% and ΔIIF A549 cells: - 13%) and depolarization of the suspended cells (ΔIIF Raji cells: + 9%). In addition, the conditioned media collected after magnetic field exposure acted on unexposed tumor cells and caused inhibition. Our findings might provide a basis for the mechanism of magnetic field interaction between cells and cell environment in the future.

The effect of magnetic fields on tumor occurrence and progression: Recent advances

Malignancies are the leading human health threat worldwide. Despite rapidly developing treatments, poor prognosis and outcome are still common. Magnetic fields have shown good anti-tumoral effects both in vitro and in vivo, and represent a potential non-invasive treatment; however, the specific underlying molecular mechanisms remain unclear. We here review recent studies on magnetic fields and their effect on tumors at three different levels: organismal, cellular, and molecular. At the organismal level, magnetic fields suppress tumor angiogenesis, microcirculation, and enhance the immune response. At the cellular level, magnetic fields affect tumor cell growth and biological functions by affecting cell morphology, cell membrane structure, cell cycle, and mitochondrial function. At the molecular level, magnetic fields suppress tumors by interfering with DNA synthesis, reactive oxygen species level, second messenger molecule delivery, and orientation of epidermal growth factor receptors. At present, scientific experimental evidence is still lacking; therefore, systematic studies on the biological mechanisms involved are urgently needed for the future application of magnetic fields to tumor treatment.

Differential biological responses of adherent and non-adherent (cancer and non-cancerous) cells to variable extremely low frequency magnetic fields

Extremely low-frequency electromagnetic field (ELF-EMF) induces biological effects on different cells through various signaling pathways. To study the impact of the ELF-EMF on living cells under an optimal physiological condition, we have designed and constructed a novel system that eliminates several limitations of other ELF-EMF systems. Apoptosis and cell number were assessed by flow cytometry and the Trypan Blue dye exclusion method, respectively. In vitro cell survival was evaluated by colony formation assay. The distribution of cells in the cell cycle, intracellular ROS level, and autophagy were analyzed by flow cytometer. Suspended cells differentiation was assessed by phagocytosis of latex particles and NBT reduction assay. Our results showed that response to the exposure to ELF-EMF is specific and depends on the biological state of the cell. For DU145, HUVEC, and K562 cell lines the optimum results were obtained at the frequency of 0.01 Hz, while for MDA-MB-231, the optimum response was obtained at 1 Hz. Long-term exposure to ELF-EMF in adherent cells effectively inhibited proliferation by arresting the cell population at the cell cycle G2/M phase and increased intracellular ROS level, leading to morphological changes and cell death. The K562 cells exposed to the ELF-EMF differentiate via induction of autophagy and decreasing the cell number. Our novel ELF-EMF instrument could change morphological and cell behaviors, including proliferation, differentiation, and cell death.

Magnetic field effects in biology from the perspective of the radical pair mechanism

Hundreds of studies have found that weak magnetic fields can significantly influence various biological systems. However, the underlying mechanisms behind these phenomena remain elusive. Remarkably, the magnetic energies implicated in these effects are much smaller than thermal energies. Here, we review these observations, and we suggest an explanation based on the radical pair mechanism, which involves the quantum dynamics of the electron and nuclear spins of transient radical molecules. While the radical pair mechanism has been studied in detail in the context of avian magnetoreception, the studies reviewed here show that magnetosensitivity is widespread throughout biology. We review magnetic field effects on various physiological functions, discussing static, hypomagnetic and oscillating magnetic fields, as well as isotope effects. We then review the radical pair mechanism as a potential unifying model for the described magnetic field effects, and we discuss plausible candidate molecules for the radical pairs. We review recent studies proposing that the radical pair mechanism provides explanations for isotope effects in xenon anaesthesia and lithium treatment of hyperactivity, magnetic field effects on the circadian clock, and hypomagnetic field effects on neurogenesis and microtubule assembly. We conclude by discussing future lines of investigation in this exciting new area of quantum biology.

An overview of the biological effects of extremely low frequency electromagnetic fields combined with ionizing radiation

By growing the electrical power networks and electronic devices, electromagnetic fields (EMF) have become an inseparable part of the modern world. Considering the inevitable exposure to a various range of EMFs, especially at extremely low frequencies (ELF-EMF), investigating the biological effects of ELF-EMFs on biological systems became a global issue. The possible adverse consequences of these exposures were studied, along with their potential therapeutic capabilities. Also, their biological impacts in combination with other chemical and physical agents, specifically ionizing radiation (IR), as a co-carcinogen or as adjuvant therapy in combination with radiotherapy were explored. Here, we review the results of several in-vitro and in-vivo studies and discuss some proposed possible mechanisms of ELF-EMFs' actions in combination with IR. The results of these experiments could be fruitful to develop more precise safety standards for environmental ELF-EMFs exposures. Furthermore, it could evaluate the therapeutic capacities of ELF-EMFs alone or as an improver of radiotherapy.

Magnetic fields and apoptosis: a possible mechanism

The potential therapeutic uses of electromagnetic fields (EMF), part of the nonionizing radiation spectrum, increase with time. Among them, those considering the potential antitumor effects exerted by the Magnetic Fields (MFs), part of the EMF entity, have gained more and more interest. A recent review on this subject reports the MFs' effect on apoptosis of tumor cells as one of the most important breakthroughs. Apoptosis is considered a key mechanism regulating the genetic stability of cells and as such is considered of fundamental importance in cancer initiation and development. According to an atomic/sub-atomic analysis, based on quantum physics, of the complexity of biological life and the role played by oxygen and its radicals in cancer biology, a possible biophysical mechanism is described. The mechanism considers the influence of MFs on apoptosis through an effect on electron spin that is able to increase reactive oxygen species (ROS) concentration. Impacting on the delicate balance between ROS production and ROS elimination in tumor cells is considered a promising cancer therapy, affecting different biological processes, such as apoptosis and metastasis. An analysis in the literature, which allows correlation between MFs exposure characteristics and their influence on apoptosis and ROS concentration, supports the validity of the mechanism.

ROS-Related miRNAs Regulate Immune Response and Chemoradiotherapy Sensitivity in Hepatocellular Carcinoma by Comprehensive Analysis and Experiment

Reactive oxygen species (ROS) plays an essential role in the development of cancer. Here, we chose ROS-related miRNAs for consensus clustering analysis and ROS score construction. We find that ROS is extremely associated with prognosis, tumor immune microenvironment (TIME), gene mutations, N6-methyladenosine (m6A) methylation, and chemotherapy sensitivity in hepatocellular carcinoma (HCC). Mechanistically, ROS may affect the prognosis of HCC patients in numerous ways. Moreover, miR-210-3p and miR-106a-5p significantly increased the ROS level and stagnated cell cycle at G2/M in HCC; the results were more obvious in cells after ionizing radiation (IR). Finally, the two miRNAs suppressed cell proliferation, migration, and invasion and promoted apoptosis in huh7 and smmc7721 cells. It indicated that ROS might affect the prognosis of HCC patients through immune response and increase the sensitivity of HCC patients to radiotherapy and chemotherapy.

Magnetic Fields and Cancer: Epidemiology, Cellular Biology, and Theranostics

Humans are exposed to a complex mix of man-made electric and magnetic fields (MFs) at many different frequencies, at home and at work. Epidemiological studies indicate that there is a positive relationship between residential/domestic and occupational exposure to extremely low frequency electromagnetic fields and some types of cancer, although some other studies indicate no relationship. In this review, after an introduction on the MF definition and a description of natural/anthropogenic sources, the epidemiology of residential/domestic and occupational exposure to MFs and cancer is reviewed, with reference to leukemia, brain, and breast cancer. The in vivo and in vitro effects of MFs on cancer are reviewed considering both human and animal cells, with particular reference to the involvement of reactive oxygen species (ROS). MF application on cancer diagnostic and therapy (theranostic) are also reviewed by describing the use of different magnetic resonance imaging (MRI) applications for the detection of several cancers. Finally, the use of magnetic nanoparticles is described in terms of treatment of cancer by nanomedical applications for the precise delivery of anticancer drugs, nanosurgery by magnetomechanic methods, and selective killing of cancer cells by magnetic hyperthermia. The supplementary tables provide quantitative data and methodologies in epidemiological and cell biology studies. Although scientists do not generally agree that there is a cause-effect relationship between exposure to MF and cancer, MFs might not be the direct cause of cancer but may contribute to produce ROS and generate oxidative stress, which could trigger or enhance the expression of oncogenes.

Progressive Study on the Non-thermal Effects of Magnetic Field Therapy in Oncology

Cancer is one of the most common causes of death worldwide. Although the existing therapies have made great progress and significantly improved the prognosis of patients, it is undeniable that these treatment measures still cause some serious side effects. In this context, a new treatment method is needed to address these shortcomings. In recent years, the magnetic fields have been proposed as a novel treatment method with the advantages of less side effects, high efficiency, wide applications, and low costs without forming scars. Previous studies reported that static magnetic fields (SMFs) and low-frequency magnetic fields (LF-MFs, frequency below 300 Hz) exert anti-tumor function, independent of thermal effects. Magnetic fields (MFs) could inhibit cell growth and proliferation; induce cell cycle arrest, apoptosis, autophagy, and differentiation; regulate the immune system; and suppress angiogenesis and metastasis via various signaling pathways. In addition, they are effective in combination therapies: MFs not only promote the absorption of chemotherapy drugs by producing small holes on the surface of cell membrane but also enhance the inhibitory effects by regulating apoptosis and cell cycle related proteins. At present, MFs can be used as drug delivery systems to target magnetic nanoparticles (MNPs) to tumors. This review aims to summarize and analyze the current knowledge of the pre-clinical studies of anti-tumor effects and their underlying mechanisms and discuss the prospects of the application of MF therapy in cancer prevention and treatment.

Effect of extremely low frequency electromagnetic field parameters on the proliferation of human breast cancer

Extremely low-frequency electromagnetic field (ELF-EMF) exposures influence many biological systems. These effects are mainly related to the intensity, duration, frequency, and pattern of the ELF-EMF. Our intent was to characterize the effect of specific pulsed electromagnetic fields on the in vitro proliferation of MCF-7 adenocarcinoma and MDA-MB-231 breast cancer cell lines and one non-cancerous M10 breast epithelial cell line. The following four important parameters of ELF-EMF were examined: frequencies (7.83 ± 0.3, 23.49 ± 0.3, and 39.15 ± 0.3 Hz), flux density (0.5 and 1 mT), exposure duration (12, 24, and 48 h), and the exposure methodology (continuous exposure versus switching exposure). The viability of MDA-MB-231 cells exposed to the optimized ELF-EMF pattern (7.83 ± 0.3 Hz, 1 mT, and 6 h switching exposure) was 40.1%. By contrast, the optimized ELF-EMF parameters that were most cytotoxic to breast cancer MDA-MB-231 cells were not damaging to normal M10 cells. In vitro studies also showed that exposure of MDA-MB-231 cells to the optimized ELF-EMF pattern promoted Ca²⁺ influx and resulted in apoptosis. These data confirm that exposure to this specific ELF-EMF pattern can influence cellular processes and inhibit cancer cell growth. The specific ELF-EMF pattern determined in this study may provide a potential anti-cancer treatment in the future.

The Influence of the Extremely Low Frequency Electromagnetic Field on Clear Cell Renal Carcinoma

The development of new technologies and industry is conducive to the increase in the number and variety of electromagnetic field (EMF) sources in our environment. The main sources of EMF are high-voltage lines, household appliances, audio/video devices, mobile phones, radio stations, and radar devices. In the growing use of electronic devices, scientists are increasingly interested in the effects of EMF on human health. Even though many studies on the effects of EMF have already been carried out, none of them has shown a significant effect on mammals, including humans. Moreover, it is not entirely clear how EMF influences cell behavior. The International Agency for Research on Cancer on 31 May 2011, classified PEM as a possible carcinogenic factor. This study aimed to investigate the effect of the electromagnetic field on morphological and functional changes in clear cell renal carcinoma. The research was carried out on in vitro cultures of four cell lines: HEK293, 786-O 769-P, and Caki1. The results of the research showed that the EMF of low frequency had a slight effect on the viability of cells. EMF, which induced cell arrest in the G1 phase, increased the number of early apoptotic cells and decreased the number of viable cells in the 786-O line. EMF did not affect the proliferation and viability of HEK293 cells. Extreme low-frequency EMF (ELF-EMF) also showed an inhibitory effect on the migration and metastatic properties of clear cell kidney cancer cells. Moreover, shortly after the end of ELF-EMF exposure, significant increases in ROS levels were observed in all tested cell lines. As part of the work, it was shown that low-frequency EMF shows an inhibitory effect on the proliferation of primary cancer cells, diminishing their migratory, invasive, and metastatic abilities. It also increases the apoptosis of cancer cells and the amount of reactive oxygen species. Based on the results of our research, we want to point up that the effect of ELF-EMF depends on a specific metabolic state or at a specific stage in the cell cycle of the cells under study.

Low-Frequency Magnetic Fields (LF-MFs) Inhibit Proliferation by Triggering Apoptosis and Altering Cell Cycle Distribution in Breast Cancer Cells

Breast cancer is a common malignancy threatening women’s health around the world. Despite improved treatments for different subtypes of breast tumors that have been put forward, there still exists a poor therapeutic response and prognosis. Magnetic fields, as a non-invasive therapy, have shown anti-tumor effects in vitro and in vivo; however, the detailed mechanisms involved are still not clear. In this study, we found that in exposure to low-frequency magnetic fields (LF-MFs) with an intensity of 1 mT and frequencies of 50, 125, 200, and 275 Hz, separately, the proliferation of breast cancer cells was inhibited and LF-MF with 200 Hz reached the optimum inhibition effect, on exposure time-dependently. Notably, we found that exposure to LF-MF led to MCF-7 and ZR-75-1 cell apoptosis and cell cycle arrest. Moreover, we also discovered that LF-MF effectively increased the level of reactive oxygen species (ROS), suppressed the PI3K/AKT signaling pathway, and activated glycogen synthase kinase-3β (GSK-3β). We demonstrated that the GSK3β activity contributed to LF-MF-induced cell proliferation inhibition and apoptosis, while the underlying mechanism was associated with the inhibition of PI3K/AKT through increasing the intracellular ROS accumulation. These results indicate that LF-MF with a specific frequency may be an attractive therapy to treat breast cancers.

The efficacy and safety of low-frequency rotating static magnetic field therapy combined with chemotherapy on advanced lung cancer patients: a randomized, double-blinded, controlled clinical trial

Purpose: To evaluate the efficacy and safety of magnetic field (MF) therapy by a randomized, double-blinded, controlled clinical trial.Materials and methods: From February 2016 to August 2019, patients with advanced lung cancer who conformed to inclusion criteria were enrolled in this study. Patients were assigned into MF therapy group (MF group, receiving both MF therapy and chemotherapy) and control group (CON group, receiving sham MF therapy and chemotherapy) randomly. The treatment course was 21 days and 2 hours per day. Changes of life quality assessment scales, objective response rate (ORR) and disease control rate (DCR) were analyzed as primary end points. The secondary end points were progression-free survival (PFS), change of blood cytokine concentrations and safety. This study has been registered on Clinicaltrials.gov (ID: NCT02701231).Results: 77 patients were enrolled and 60 finished the study. Comparing to CON group, more patients in MF group (66.7% vs 25.9%) were experiencing life quality improvement on day 21. Besides, MF group patients had higher concentrations of IP-10 and GM-CSF, and lower concentration of sTREM-1 in plasma. However, the two groups were having similar ORR, DCR and PFS after treatment. Moreover, MF treatment did not increase adverse events in MF group.Conclusions: MF therapy could improve life quality and modulate blood cytokine concentration in advanced lung cancer patients. Hence, it might be applied as an adjuvant therapy along with chemotherapy.

Pulsed Low-Frequency Magnetic Fields Induce Tumor Membrane Disruption and Altered Cell Viability

Tumor cells express a unique cell surface glycocalyx with upregulation of sulfated glycosaminoglycans and charged glycoproteins. Little is known about how electromagnetic fields interact with this layer, particularly with regard to harnessing unique properties for therapeutic benefit. We applied a pulsed 20-millitesla (mT) magnetic field with rate of rise (dB/dt) in the msec range to cultured tumor cells to assess whether this affects membrane integrity as measured using cytolytic assays. A 10-min exposure of A549 human lung cancer cells to sequential 50- and 385-Hz oscillating magnetic fields was sufficient to induce intracellular protease release, suggesting altered membrane integrity after the field exposure. Heparinase treatment, which digests anionic sulfated glycan polymers, before exposure rendered cells insensitive to this effect. We further examined a non-neoplastic human primary cell line (lung lymphatic endothelial cells) as a typical normal host cell from the lung cancer microenvironment and found no effect of field exposure on membrane integrity. The field exposure was also sufficient to alter proliferation of tumor cells in culture, but not that of normal lymphatic cells. Pulsed magnetic field exposure of human breast cancer cells that express a sialic-acid rich glycocalyx also induced protease release, and this was partially abrogated by sialidase pretreatment, which removes cell surface anionic sialic acid. Scanning electron microscopy showed that field exposure may induce unique membrane “rippling” along with nanoscale pores on A549 cells. These effects were caused by a short exposure to pulsed 20-mT magnetic fields, and future work may examine greater magnitude effects. The proof of concept herein points to a mechanistic basis for possible applications of pulsed magnetic fields in novel anticancer strategies.

Exposure to Static and Extremely-Low Frequency Electromagnetic Fields and Cellular Free Radicals

This paper summarizes studies on changes in cellular free radical activities from exposure to static and extremely-low frequency (ELF) electromagnetic fields (EMF), particularly magnetic fields. Changes in free radical activities, including levels of cellular reactive oxygen (ROS)/nitrogen (RNS) species and endogenous antioxidant enzymes and compounds that maintain physiological free radical concentrations in cells, is one of the most consistent effects of EMF exposure. These changes have been reported to affect many physiological functions such as DNA damage; immune response; inflammatory response; cell proliferation and differentiation; wound healing; neural electrical activities; and behavior. An important consideration is the effects of EMF-induced changes in free radicals on cell proliferation and differentiation. These cellular processes could affect cancer development and proper growth and development in organisms. On the other hand, they could cause selective killing of cancer cells, for instance, via the generation of the highly cytotoxic hydroxyl free radical by the Fenton Reaction. This provides a possibility of using these electromagnetic fields as a non-invasive and low side-effect cancer therapy. Static- and ELF-EMF probably play important roles in the evolution of living organisms. They are cues used in many critical survival functions, such as foraging, migration, and reproduction. Living organisms can detect and respond immediately to low environmental levels of these fields. Free radical processes are involved in some of these mechanisms. At this time, there is no credible hypothesis or mechanism that can adequately explain all the observed effects of static- and ELF-EMF on free radical processes. We are actually at the impasse that there are more questions than answers.

Tailoring Bacteria Response by Piezoelectric Stimulation

Bacteria are simple organisms with a remarkable capacity for survival by adapting to different environments, which is a result of their long evolutionary history. Taking into consideration these adapting mechanisms, this work now investigates the effect of electrically active microenvironments on bacteria and on how this stimulation may trigger bacteria growth inhibition or proliferation. Electrical microenvironments are generated via stimulation of a piezoelectric polymer with a mechanical cue, thus developing an electrical response and a variation on the surface charge of the polymeric material. Specifically, Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli were grown overnight under static and dynamic conditions on piezoelectric poly(vinylidene) fluoride (PVDF) films to further study bacteria behavior under: (i) the effect of the material surface charge in static conditions, (ii) the mechanical effect, and (iii) the piezoelectric effect, the last two performed under dynamic conditions. Bacteria viability in planktonic and biofilm forms was measured, and the microorganism morphology was characterized. Whereas E. coli responds little to any of the stimuli application, S. epidermidis growth can be regulated through the material surface charge and by the applied frequency. Positively charged PVDF induces bacterial growth inhibition in planktonic and adhered cells in static conditions, whereas antifouling properties are obtained when a mechanical or piezoelectric effect at 4 Hz stimuli is applied. By increasing the stimuli to 40 Hz, however, the adhesion of bacteria is promoted. In conclusion, the behavior of certain bacteria species is tailored through the application of piezoelectric materials, which provide sufficient mechanoelectrical stimuli for growth or inhibition of bacteria, allowing for the design of suitable anti- and promicrobial strategies. Such strategies are only found in studies related to mammalian cells, whereas in bacterial cells this type of stimuli are still unknown. Thus, this work provides one of the first insights on the effect of piezoelectric stimuli on bacterial cells.

ROS Reduction Does Not Decrease the Anticancer Efficacy of X-Ray in Two Breast Cancer Cell Lines

Radiotherapy is effective on a large number of cancer types and is one of the most frequently administrated treatments for cancer patients. The anticancer efficacy of X-ray radiotherapy has been frequently correlated with reactive oxygen species (ROS) elevation, which is also a limiting factor for its toxicity on normal tissues. Here, we found that although 4-10 Gy X-rays could significantly reduce cell numbers in both MDA-MB-231 and MCF-7 breast cancer cells, the ROS level changes are less in MCF-7 cells than in MDA-MB-231 cells. Moreover, although both the ROS scavenger N-acetyl-L-cysteine (NAC) and 1 T static magnetic field (SMF) could reduce X-ray-induced ROS elevation, they did not prevent X-ray-induced cell number reduction or cell death increase, which is significantly different from cisplatin. These results demonstrate that although the anticancer efficacy of cisplatin on two breast cancer cell lines is dependent on ROS, the anticancer efficacy of X-ray is not. Moreover, by testing 19 different cell lines, we found that 1 T SMF could effectively reduce ROS levels in multiple cell lines by 10-20%, which encourages further studies to investigate whether SMF could be used as a potential "physical antioxidant" in the future.

Extremely low frequency variable electromagnetic fields affect cancer and noncancerous cells in vitro differently: Preliminary study

The exposure to extremely low frequency electromagnetic field (ELF-EMF) may result in various changes at the cellular level. To identify the effect of ELF-EMF exposure on viability of cells, cancer cells (U87-MG; 143B) and noncancerous cells (BJ; HEK) in exponential growth phase were exposed or sham-exposed to different values of frequency (2, 20, 30, 50 and 60 Hz), different shapes (sinusoidal, square and triangular) and time of exposure (0.5, 1, 2, 3 h) to electromagnetic field. After exposure, viability of cells was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). We found a different effect of exposition of cancer and noncancerous cells to ELF-EMF on viability of cells. This preliminary study revealed that electro magentic field(EMF) might serve as a potential tool for manipulating viability of cells.

Magnetic Fields and Reactive Oxygen Species

Reactive oxygen species (ROS) ubiquitously exist in mammalian cells to participate in various cellular signaling pathways. The intracellular ROS levels are dependent on the dynamic balance between ROS generation and elimination. In this review, we summarize reported studies about the influences of magnetic fields (MFs) on ROS levels. Although in most cases, MFs increased ROS levels in human, mouse, rat cells, and tissues, there are also studies showing that ROS levels were decreased or not affected by MFs. Multiple factors could cause these discrepancies, including but not limited to MF type/intensity/frequency, exposure time and assay time-point, as well as different biological samples examined. It will be necessary to investigate the influences of different MFs on ROS in various biological samples systematically and mechanistically, which will be helpful for people to get a more complete understanding about MF-induced biological effects. In addition, reviewing the roles of MFs in ROS modulation may open up new scenarios of MF application, which could be further and more widely adopted into clinical applications, particularly in diseases that ROS have documented pathophysiological roles.

Low Frequency Magnetic Fields Induce Autophagy-associated Cell Death in Lung Cancer through miR-486-mediated Inhibition of Akt/mTOR Signaling Pathway

Low frequency magnetic fields (LF-MFs) can affect cell proliferation in a cell-type and intensity-dependent way. Previous study has reported the anti-tumor effect of LF-MFs in lung cancers. Our previous study also optimized the intensity and duration of LF-MFs to effectively inhibit the proliferation of lung cancer cells. However, the anti-tumor mechanism of LF-MFs remains unclear, which limit the clinical application of LF-MFs in anti-tumor therapy. Here, in a well-established Lewis Lung Cancer (LLC) mouse model, we found that LF-MFs inhibit tumor growth and induce an autophagic cell death in lung cancer. We also found that LF-MFs could up-regulate the expression level of miR-486, which was involved in LF-MFs activated cell autophagy. Furthermore, we found B-cell adaptor for phosphatidylinositol 3-kinase (BCAP) is a direct target of miR-486. miR-486 inhibit AKT/mTOR signaling through inhibiting expression of BCAP. Moreover, a decreased expression of miR-486 and an increased expression of BCAP were found in tumor tissues of lung cancer patients. Taken together, this study proved that LF-MFs can inhibit lung cancers through miR-486 induced autophagic cell death, which suggest a clinical application of LF-MFs in cancer treatment.

LF-MF inhibits iron metabolism and suppresses lung cancer through activation of P53-miR-34a-E2F1/E2F3 pathway

Our previous studies showed that low frequency magnetic fields (LF-MF) suppressed tumor growth and influenced the function of immune system. Nevertheless the mechanisms behind the effect of LF-MF still remain to be elucidated. In this study, Tumor- bearing mice subcutaneously inoculated with Lewis lung cancer cells were exposed to a LF-MF (0.4T, 7.5 Hz) for 35 days and Survival rate, tumor growth and the tumor markers were measured. Results showed that tumor growth was obviously inhibited with a prolonged survival of tumor- bearing mice by LF-MF exposure. In vitro experiments, LF-MF was found to induce cell growth arrest, cell senescence and inhibit iron metabolism of lung cancer cells. Moreover, LF-MF stabilized p53 protein via inhibiting cell iron metabolism and the stabilized p53 protein enhanced miR-34a transcription. Furthermore, increased expression of miR-34a induced cell proliferation inhibition, cell cycle arrest and cell senescence of lung cancer cells by targeting E2F1/E2F3. We also detected the relevant indicator in tumor tissue such as the iron content, the level of miR-34a and related protein, corresponding results were obtained. Taken together, these observations imply that LF-MF suppressed lung cancer via inhibiting cell iron metabolism, stabilizing p53 protein and activation P53- miR-34a-E2F1/E2F3 pathway.

Mechanisms and therapeutic effectiveness of pulsed electromagnetic field therapy in oncology

Cancer is one of the most common causes of death worldwide. Available treatments are associated with numerous side effects and only a low percentage of patients achieve complete remission. Therefore, there is a strong need for new therapeutic strategies. In this regard, pulsed electromagnetic field (PEMF) therapy presents several potential advantages including non-invasiveness, safety, lack of toxicity for non-cancerous cells, and the possibility of being combined with other available therapies. Indeed, PEMF stimulation has already been used in the context of various cancer types including skin, breast, prostate, hepatocellular, lung, ovarian, pancreatic, bladder, thyroid, and colon cancer in vitro and in vivo. At present, only limited application of PEMF in cancer has been documented in humans. In this article, we review the experimental and clinical evidence of PEMF therapy discussing future perspectives in its use in oncology.

Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing

Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Consequently, the bacteria are selectively killed on the cathode surface. However, the cell experiment suggested that the level of ROS is safe for normal mammalian cells.

Positive geotactic behaviors induced by geomagnetic field in Drosophila

Background

Appropriate vertical movement is critical for the survival of flying animals. Although negative geotaxis (moving away from Earth) driven by gravity has been extensively studied, much less is understood concerning a static regulatory mechanism for inducing positive geotaxis (moving toward Earth).

Results

Using Drosophila melanogaster as a model organism, we showed that geomagnetic field (GMF) induces positive geotaxis and antagonizes negative gravitaxis. Remarkably, GMF acts as a sensory cue for an appetite-driven associative learning behavior through the GMF-induced positive geotaxis. This GMF-induced positive geotaxis requires the three geotaxis genes, such as cry, pyx and pdf, and the corresponding neurons residing in Johnston’s organ of the fly’s antennae.

Conclusions

These findings provide a novel concept with the neurogenetic basis on the regulation of vertical movement by GMF in the flying animals.

Electronic supplementary material

The online version of this article (doi:10.1186/s13041-016-0235-1) contains supplementary material, which is available to authorized users.

Effect of 50 Hz Extremely Low-Frequency Electromagnetic Fields on the DNA Methylation and DNA Methyltransferases in Mouse Spermatocyte-Derived Cell Line GC-2

Previous studies have shown that the male reproductive system is one of the most sensitive organs to electromagnetic radiation. However, the biological effects and molecular mechanism are largely unclear. Our study was designed to elucidate the epigenetic effects of 50 Hz ELF-EMF in vitro. Mouse spermatocyte-derived GC-2 cell line was exposed to 50 Hz ELF-EMF (5 min on and 10 min off) at magnetic field intensity of 1 mT, 2 mT, and 3 mT with an intermittent exposure for 72 h. We found that 50 Hz ELF-EMF exposure decreased genome-wide methylation at 1 mT, but global methylation was higher at 3 mT compared with the controls. The expression of DNMT1 and DNMT3b was decreased at 1 mT, and 50 Hz ELF-EMF can increase the expression of DNMT1 and DNMT3b of GC-2 cells at 3 mT. However, 50 Hz ELF-EMF had little influence on the expression of DNMT3a. Then, we established DNA methylation and gene expression profiling and validated some genes with aberrant DNA methylation and expression at different intensity of 50 Hz ELF-EMF. These results suggest that the alterations of genome-wide methylation and DNMTs expression may play an important role in the biological effects of 50 Hz ELF-EMF exposure.

Extremely low-frequency magnetic fields induce developmental toxicity and apoptosis in zebrafish (Danio rerio) embryos

Extremely low-frequency (ELF) magnetic field (MF), as a widespread ecological factor, has an influence on all living beings. In the present study, biological effects of ELF-MF on the development of zebrafish (Danio rerio) embryos were investigated. Fertilized embryos were divided into seven groups as control, sham, and five experimental groups. Embryos of experimental groups were continuously exposed to 50-Hz sinusoidal MF with intensities of 30, 100, 200, 400, and 800 μT for 96 h. The sham group was treated as the experimental groups, but without any ELF-MF exposure. The control group was not subjected to anything. The results showed that ELF-MF exposure caused delayed hatching and decreased heart rate at the early developmental stages of zebrafish embryos, whereas no significant differences in embryo mortality and abnormality were observed. Moreover, acridine orange staining assays showed notable signals of apoptosis mainly in the ventral fin and spinal column. The transcription of apoptosis-related genes (caspase-3, caspase-9) was significantly upregulated in ELF-MF-exposed embryos. In conclusion, the overall results demonstrated that ELF-MF exposure has detrimental effects on the embryonic development of zebrafish by affecting the hatching, decreasing the heart rate, and inducing apoptosis, although such effects were not mortal threat. The results also indicate that zebrafish embryos can serve as a reliable model to investigate the biological effect of ELF-MF.

Power frequency magnetic fields induced reactive oxygen species-related autophagy in mouse embryonic fibroblasts

Power frequency magnetic fields (PFMF) have been reported to affect several cellular functions, such as cell proliferation and apoptosis. In this study, we investigated the effects of PFMF on mouse embryonic fibroblasts (MEF) autophagy. After cells were exposed to 50 Hz PFMF at 2 mT for 0.5 h, 2 h, 6 h, 12 h, and 24 h, we observed a significant increase in autophagic markers at 6 h, including (i) higher microtubule-associated protein 1 light chain 3-II (LC3-II), (ii) the increased formation of GFP-LC3 puncta, and (iii) increased numbers of autophagic vacuoles under transmission electron microscope. Moreover, we provide convincing evidence using chloroquine (CQ) that the increase of autophagic markers was the result of enhanced autophagic flux and not the suppression of lysosomal function. In a search for molecular mechanisms underlying PFMF-mediated autophagy, we observe that the autophagic process involved reactive oxygen species (ROS) and was independent of the mammalian target of rapamycin (mTOR) signaling pathway.

Intermediate frequency magnetic field generated by a wireless power transmission device does not cause genotoxicity in vitro

The aim of this study was to evaluate effects of intermediate frequency magnetic fields (IFMF) generated by a wireless power transmission (WPT) based on magnetic resonance from the perspective of cellular genotoxicity on cultured human lens epithelial cells (HLECs). We evaluated the effects of exposure to 90 kHz magnetic fields at 93.36 µT on cellular genotoxicity in vitro for 2 and 4 h. The magnetic flux density is approximately 3.5 times higher than the reference level recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. For assessment of genotoxicity, we studied cellular proliferation, apoptosis and DNA damage by Cell Counting Kit-8 (CCK-8) assay, flow cytometry analysis, alkaline comet assay and phosphorylated histone H2AX (γH2AX) foci formation test. We did not detect any effect of a 90 kHz IFMF generated by WPT based on magnetic resonance on cell proliferation, apoptosis, comet assay, and γH2AX foci formation test. Our results indicated that exposure to 90 kHz IFMF generated by WPT based on magnetic resonance at 93.36 µT for 2 and 4 h does not cause detectable cellular genotoxicity.

Grouping of Experimental Conditions as an Approach to Evaluate Effects of Extremely Low-Frequency Magnetic Fields on Oxidative Response in in vitro Studies

A large body of literature deals with biological effects of extremely low-frequency magnetic fields (ELF MFs) studied in vitro. Despite the multitude of studies, no coherent picture has evolved regarding the plausibility of effects at low-flux densities or regarding the interaction mechanisms. Here, we propose that ELF MF exposure in vitro causes changes in oxidative status as an early response. We tested this hypothesis by scrutinizing the literature and applying a grouping approach for analyzing relevant biological properties and exposure conditions. A total of 41 scientific original publications were analyzed for this purpose. The conclusion from the work is that ELF MF (modulated or unmodulated) consistently can influence the oxidative status, at or above 1 mT, in a broad range of cell types and independent of exposure duration. A response at lower flux densities is seen in certain studies, although not consistently. Further studies with stringent protocols for sham exposure, blinding, and statistical analysis as well as appropriate positive controls are needed to establish if true dose-relationships for effects on oxidative status exist.

Effect of low frequency magnetic fields on melanoma: tumor inhibition and immune modulation

BACKGROUND

We previously found that the low frequency magnetic fields (LF-MF) inhibited gastric and lung cancer cell growth. We suppose that exposure to LF-MF may modulate immune function so as to inhibit tumor. We here investigated whether LF-MF can inhibit the proliferation and metastasis of melanoma and influence immune function.

METHODS

The effect of MF on the proliferation, cell cycle and ultrastracture of B16-F10 in vitro was detected by cell counting Kit-8 assay, flow cytometry, and transmission electron microscopy. Lung metastasis mice were prepared by injection of 2 × 105 B16-F10 melanoma cells into the tail vein in C57BL/6 mice. The mice were then exposed to an LF-MF (0.4 T, 7.5 Hz) for 43 days. Survival rate, tumor markers and the innate and adaptive immune parameters were measured.

RESULTS

The growth of B16-F10 cells was inhibited after exposure to the LF-MF. The inhibition was related to induction of cell cycle arrest and decomposition of chromatins. Moreover, the LF-MF prolonged the mouse survival rate and inhibited the proliferation of B16-F10 in melanoma metastasis mice model. Furthermore, the LF-MF modulated the immune response via regulation of immune cells and cytokine production. In addition, the number of Treg cells was decreased in mice with the LF-MF exposure, while the numbers of T cells as well as dendritic cells were significantly increased.

CONCLUSION

LF-MF inhibited the growth and metastasis of melanoma cancer cells and improved immune function of tumor-bearing mice. This suggests that the inhibition may be attributed to modulation of LF-MF on immune function and LF-MF may be a potential therapy for treatment of melanoma.

Low frequency magnetic fields enhance antitumor immune response against mouse H22 hepatocellular carcinoma

Objective

Many studies have shown that magnetic fields (MF) inhibit tumor growth and influence the function of immune system. However, the effect of MF on mechanism of immunological function in tumor-bearing mice is still unclear.

Methods

In this study, tumor-bearing mice were prepared by subcutaneously inoculating Balb/c mice with hepatocarcinoma cell line H22. The mice were then exposed to a low frequency MF (0.4 T, 7.5 Hz) for 30 days. Survival rate, tumor growth and the innate and adaptive immune parameters were measured.

Results

MF treatment could prolong survival time (n = 28, p<0.05) and inhibit tumor growth (n = 9, p<0.01) in tumor-bearing mice. Moreover, this MF suppressed tumor-induced production of cytokines including interleukin-6 (IL-6), granulocyte colony- stimulating factor (G-CSF) and keratinocyte-derived chemokine (KC) (n = 9–10, p<0.05 or 0.01). Furthermore, MF exposure was associated with activation of macrophages and dendritic cells, enhanced profiles of CD4⁺ T and CD8⁺ T lymphocytes, the balance of Th17/Treg and reduced inhibitory function of Treg cells (n = 9–10, p<0.05 or 0.01) in the mice model.

Conclusion

The inhibitory effect of MF on tumor growth was related to the improvement of immune function in the tumor-bearing mice.

Low intensity and frequency pulsed electromagnetic fields selectively impair breast cancer cell viability

INTRODUCTION

A common drawback of many anticancer therapies is non-specificity in action of killing. We investigated the potential of ultra-low intensity and frequency pulsed electromagnetic fields (PEMFs) to kill breast cancer cells. Our criteria to accept this technology as a potentially valid therapeutic approach were: 1) cytotoxicity to breast cancer cells and; 2) that the designed fields proved innocuous to healthy cell classes that would be exposed to the PEMFs during clinical treatment.

METHODS

MCF7 breast cancer cells and their normal counterparts, MCF10 cells, were exposed to PEMFs and cytotoxic indices measured in order to design PEMF paradigms that best kill breast cancer cells. The PEMF parameters tested were: 1) frequencies ranging from 20 to 50 Hz; 2) intensities ranging from 2 mT to 5 mT and; 3) exposure durations ranging from 30 to 90 minutes per day for up to three days to determine the optimum parameters for selective cancer cell killing.

RESULTS

We observed a discrete window of vulnerability of MCF7 cells to PEMFs of 20 Hz frequency, 3 mT magnitude and exposure duration of 60 minutes per day. The cell damage accrued in response to PEMFs increased with time and gained significance after three days of consecutive daily exposure. By contrast, the PEMFs parameters determined to be most cytotoxic to breast cancer MCF-7 cells were not damaging to normal MCF-10 cells.

CONCLUSION

Based on our data it appears that PEMF-based anticancer strategies may represent a new therapeutic approach to treat breast cancer without affecting normal tissues in a manner that is non-invasive and can be potentially combined with existing anti-cancer treatments.

Electromagnetic field-induced converse cell growth during a long-term observation

PURPOSE

Professional and public concern about the potential adverse effects of man-made electromagnetic fields (EMF) on the human body has dramatically expanded in recent years. Despite numerous attempts to investigate this issue, the long-standing challenge of reproducibility surrounding alternating EMF effects on human health remains unresolved. Our chief aim was to investigate a plausible mechanism for this phenomenon.

MATERIALS AND METHODS

Growth of cultured human cancer cells, DU145 and Jurkat, exposed to power frequency magnetic field (MF) (60 Hz, 1 mT) for 3 days, was determined using a 2-(4-Iodophenyl)- 3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium (WST-1) assay and a trypan blue exclusion assay. This experiment was repeated at incubators long-term monitoring period up to 5.3 years. A periodogram analysis was performed to investigate periodic patterns in the MF and sham effects on cell growth.

RESULTS

Unlike conventional assumptions, the MF effect on growth in both cell types was promotive or suppressive in a period-dependent manner. The converse cell growth induced by the MF was consistent in incubators, with little variation.

CONCLUSIONS

Spatiotemporal evidence suggests that the period-dependent converse cell growth by the MF may contribute to the poor reproducibility and explain the adverse effects observed in previous experimental and epidemiological investigations. Additionally, the novel approach of this study may be applied to design features required to experimentally determine the effects of EMF on living organisms in a convincing manner.

Upsides and downsides of reactive oxygen species for cancer: the roles of reactive oxygen species in tumorigenesis, prevention, and therapy

SIGNIFICANCE

Extensive research during the last quarter century has revealed that reactive oxygen species (ROS) produced in the body, primarily by the mitochondria, play a major role in various cell-signaling pathways. Most risk factors associated with chronic diseases (e.g., cancer), such as stress, tobacco, environmental pollutants, radiation, viral infection, diet, and bacterial infection, interact with cells through the generation of ROS.

RECENT ADVANCES

ROS, in turn, activate various transcription factors (e.g., nuclear factor kappa-light-chain-enhancer of activated B cells [NF-κB], activator protein-1, hypoxia-inducible factor-1α, and signal transducer and activator of transcription 3), resulting in the expression of proteins that control inflammation, cellular transformation, tumor cell survival, tumor cell proliferation and invasion, angiogenesis, and metastasis. Paradoxically, ROS also control the expression of various tumor suppressor genes (p53, Rb, and PTEN). Similarly, γ-radiation and various chemotherapeutic agents used to treat cancer mediate their effects through the production of ROS. Interestingly, ROS have also been implicated in the chemopreventive and anti-tumor action of nutraceuticals derived from fruits, vegetables, spices, and other natural products used in traditional medicine.

CRITICAL ISSUES

These statements suggest both "upside" (cancer-suppressing) and "downside" (cancer-promoting) actions of the ROS. Thus, similar to tumor necrosis factor-α, inflammation, and NF-κB, ROS act as a double-edged sword. This paradox provides a great challenge for researchers whose aim is to exploit ROS stress for the development of cancer therapies.

FUTURE DIRECTIONS

the various mechanisms by which ROS mediate paradoxical effects are discussed in this article. The outstanding questions and future directions raised by our current understanding are discussed.

Effects of power frequency electromagnetic fields on melatonin and sleep in the rat

Background

Studies investigating the effect of power frequency (50–60 Hz) electromagnetic fields (EMF) on melatonin synthesis in rats have been inconsistent with several showing suppression of melatonin synthesis, others showing no effect and a few actually demonstrating small increases. Scant research has focused on the ensuing sleep patterns of EMF exposed rats. The present study was designed to examine the effects of extremely low power frequency electromagnetic fields (EMF) on the production of melatonin and the subsequent sleep structure in rats.

Methods

Eighteen male Sprague-Dawley rats were exposed to a 1000 milligauss (mG) magnetic field for 1 month. Urine was collected for the final 3 days of the exposure period for analysis of 6-sulphatoxymelatonin, the major catabolic product of melatonin found in urine. Subsequent sleep was analyzed over a 24-hour period.

Results

Melatonin production was mildly increased in exposed animals. Although there were no statistically significant changes in sleep structure, exposed animals showed slight decreases in REM (rapid eye movement) sleep as compared to sham (non-exposed) animals.

Conclusions

Power frequency magnetic fields induced a marginally statistically significant increase in melatonin levels in exposed rats compared to control. Subsequent sleep analysis indicated little effect on the sleep architecture of rats, at least not within the first day after 1 month's continuous exposure. Varying results in the literature are discussed and future research suggested.

Effect of electromagnetic field exposure on the reproductive system

The safety of human exposure to an ever-increasing number and diversity of electromagnetic field (EMF) sources both at work and at home has become a public health issue. To date, many in vivo and in vitro studies have revealed that EMF exposure can alter cellular homeostasis, endocrine function, reproductive function, and fetal development in animal systems. Reproductive parameters reported to be altered by EMF exposure include male germ cell death, the estrous cycle, reproductive endocrine hormones, reproductive organ weights, sperm motility, early embryonic development, and pregnancy success. At the cellular level, an increase in free radicals and [Ca²⁺]i may mediate the effect of EMFs and lead to cell growth inhibition, protein misfolding, and DNA breaks. The effect of EMF exposure on reproductive function differs according to frequency and wave, strength (energy), and duration of exposure. In the present review, the effects of EMFs on reproductive function are summarized according to the types of EMF, wave type, strength, and duration of exposure at cellular and organism levels.

Selective destabilization of tumor cells with pulsed electric and magnetic sequences: a preliminary report

BACKGROUND

Various studies in vitro suggest that low electric and magnetic fields may modify cancer cell growth and recent studies in vivo have revealed anti-tumoral effects. After screening different tumor cell lines, we identified specific sequences of localized magnetic and electric fields (MESQ) that reduce cancer cell survival in vitro. This finding led us to design an experiment to determine the actual efficacy of above sequences in selectively destabilizing tumor cells and their effect on healthy cells.

MATERIALS AND METHODS

We exposed the MCF7 cancer cell line and normal fibroblasts to MESQ for 1, 2, 3 and 6 hours, evaluating cell survival and induction of apoptosis.

RESULTS

Exposure to MESQ reduced MCF7 survival, inducing apoptosis in a timedependent way, whereas fibroblasts were completely unaffected.

CONCLUSION

These results have promising implications for the treatment of cancer and warrant further research.

Involvement of midkine expression in the inhibitory effects of low-frequency magnetic fields on cancer cells

Effects of magnetic fields (MFs) on cancer cells may depend on cell type and exposure conditions. Gene expression levels are different among cancer cells. However, the effect of MFs on cancer cells with different gene expressions is still unclear. In this study, the cancer cell lines BGC-823, MKN-45, MKN-28, A549, SPC-A1, and LOVO were exposed to a low-frequency MF. Specific parameters of MFs were determined. Furthermore, the potential of the MF to influence cancer cell growth with midkine (MK) expression was evaluated. Cell proliferation and cell cycle were detected using the CCK-8 assay and flow cytometry. Cell ultrastructure was observed by transmission electron microscopy. BGC-823 cells with over-expression of MK (BGC-MK cells) and stanniocalcin-1 were generated by plasmid construction and transfection. Results showed that exposure to a 0.4-T, 7.5 Hz MF inhibited the proliferation of BGC-823, MKN-28, A549, and LOVO cells, but not MKN-45 and SPC-A1 cells. Moreover, the inhibitory effect of the MF on BGC-MK cells was lower (12.3%) than that of BGC-823 cells (20.3%). Analysis of the cell cycle showed that exposure to the MF led to a significant increase in the S phase in BGC-823 cells, but not in BGC-MK cells. In addition, organelle morphology was modified in BGC-823 cells exposed to the MF. These results suggest that exposure to a 0.4-T, 7.5 Hz MF could inhibit tumor cell proliferation and disturb the cell cycle. The alteration of MK expression in cancer cells may be related to the inhibitory effect of the MF on these cells.