Inhibition of cancer cell growth by exposure to a specific time-varying electromagnetic field involves T-type calcium channels.

PloS one · 2015 · Benefit · Low evidence

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BenefitLow evidencePaper 4782

Study snapshot

PublicationPloS one · 2015

Study typeanimal

Reported directionBenefit

Evidence ratingLow

Abstract

Electromagnetic field (EMF) exposures affect many biological systems. The reproducibility of these effects is related to the intensity, duration, frequency, and pattern of the EMF. We have shown that exposure to a specific time-varying EMF can inhibit the growth of malignant cells. Thomas-EMF is a low-intensity, frequency-modulated (25-6 Hz) EMF pattern. Daily, 1 h, exposures to Thomas-EMF inhibited the growth of malignant cell lines including B16-BL6, MDA-MB-231, MCF-7, and HeLa cells but did not affect the growth of non-malignant cells. Thomas-EMF also inhibited B16-BL6 cell proliferation in vivo. B16-BL6 cells implanted in syngeneic C57b mice and exposed daily to Thomas-EMF produced smaller tumours than in sham-treated controls. In vitro studies showed that exposure of malignant cells to Thomas-EMF for > 15 min promoted Ca(2+) influx which could be blocked by inhibitors of voltage-gated T-type Ca(2+) channels. Blocking Ca(2+) uptake also blocked Thomas-EMF-dependent inhibition of cell proliferation. Exposure to Thomas-EMF delayed cell cycle progression and altered cyclin expression consistent with the decrease in cell proliferation. Non-malignant cells did not show any EMF-dependent changes in Ca(2+) influx or cell growth. These data confirm that exposure to a specific EMF pattern can affect cellular processes and that exposure to Thomas-EMF may provide a potential anti-cancer therapy.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeanimal

Effect directionbenefit

PopulationCancer cell lines (B16-BL6, MDA-MB-231, MCF-7, HeLa) and non-malignant cells; syngeneic C57b mice implanted with B16-BL6 cells

Sample sizeNot supplied

ExposureELF · Daily 1 h exposures; in vitro >15 min for Ca2+ influx effects

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

A low-intensity, frequency-modulated time-varying EMF pattern (Thomas-EMF; 25–6 Hz) inhibited growth of multiple malignant cell lines with daily 1 h exposures, while not affecting non-malignant cell growth. In syngeneic C57b mice implanted with B16-BL6 cells, daily Thomas-EMF exposure produced smaller tumours than sham controls. In vitro, >15 min exposure promoted Ca2+ influx that was blocked by T-type Ca2+ channel inhibitors, and blocking Ca2+ uptake also blocked the EMF-dependent inhibition of proliferation; exposure also delayed cell cycle progression and altered cyclin expression.

Outcomes measured

Cancer cell growth/proliferation (in vitro)
Tumour size/growth (in vivo)
Ca2+ influx
T-type voltage-gated calcium channel involvement (pharmacologic inhibition)
Cell cycle progression
Cyclin expression

Limitations

Sample size not reported in abstract
Exposure intensity not quantified in abstract (only described as low-intensity)
Details of sham exposure conditions not provided in abstract
In vivo findings limited to one tumour model/cell line (B16-BL6) in mice

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "Daily 1 h exposures; in vitro >15 min for Ca2+ influx effects"
  },
  "population": "Cancer cell lines (B16-BL6, MDA-MB-231, MCF-7, HeLa) and non-malignant cells; syngeneic C57b mice implanted with B16-BL6 cells",
  "sample_size": null,
  "outcomes": [
    "Cancer cell growth/proliferation (in vitro)",
    "Tumour size/growth (in vivo)",
    "Ca2+ influx",
    "T-type voltage-gated calcium channel involvement (pharmacologic inhibition)",
    "Cell cycle progression",
    "Cyclin expression"
  ],
  "main_findings": "A low-intensity, frequency-modulated time-varying EMF pattern (Thomas-EMF; 25–6 Hz) inhibited growth of multiple malignant cell lines with daily 1 h exposures, while not affecting non-malignant cell growth. In syngeneic C57b mice implanted with B16-BL6 cells, daily Thomas-EMF exposure produced smaller tumours than sham controls. In vitro, >15 min exposure promoted Ca2+ influx that was blocked by T-type Ca2+ channel inhibitors, and blocking Ca2+ uptake also blocked the EMF-dependent inhibition of proliferation; exposure also delayed cell cycle progression and altered cyclin expression.",
  "effect_direction": "benefit",
  "limitations": [
    "Sample size not reported in abstract",
    "Exposure intensity not quantified in abstract (only described as low-intensity)",
    "Details of sham exposure conditions not provided in abstract",
    "In vivo findings limited to one tumour model/cell line (B16-BL6) in mice"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "time-varying electromagnetic field",
    "Thomas-EMF",
    "ELF",
    "frequency-modulated",
    "25-6 Hz",
    "cancer cell lines",
    "tumour growth",
    "B16-BL6",
    "MDA-MB-231",
    "MCF-7",
    "HeLa",
    "Ca2+ influx",
    "T-type calcium channels",
    "cell cycle",
    "cyclins"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1371/journal.pone.0124136
PubMed: 25875081

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