A Theoretical Study on the Biophysical Mechanisms by Which Tumor Treating Fields Affect Tumor Cells during Mitosis

2020 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 1608

Study snapshot

Publicationmanual · 2020

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

A Theoretical Study on the Biophysical Mechanisms by Which Tumor Treating Fields Affect Tumor Cells during Mitosis Li X, Yang F, Rubinsky B. A Theoretical Study on the Biophysical Mechanisms by Which Tumor Treating Fields Affect Tumor Cells during Mitosis. IEEE Trans Biomed Eng. 2020 Jan 13. doi: 10.1109/TBME.2020.2965883. Abstract OBJECTIVE: A theoretical study on the mechanisms through which Tumor Treating Fields (TTFields) affect dividing tumor cells. METHODS: Numerical analysis was used to revisit two previously proposed mechanisms and introduce a third. We examine the previous hypotheses that: a) TTFields generate a moment that affects microtubule assembly during early mitosis, and b) dielectrophoretic (DEP) forces cause neutral particles to move toward the cleavage furrow during the telophase stage. We further introduce a new hypothesis that TTFields modify cell membrane potential in dividing tumor cells. RESULTS: a) The Brownian energy is several orders of magnitude larger than the moment induced by TTFields on tubulin dimers. b) Adding Stokes drag forces to DEP forces shows that the motion of the particles in the cytoplasm is very slow, approximately 0.003 μm/s, and therefore, unless the duration of the telophase is long enough there will be no substantial effect from the DEP forces. c) The Schwan equation shows that electric fields at the frequencies of clinical TTFields can cause a 10% - 17% change in tumor cell membrane potential. CONCLUSION: Our studies find limited support for the previously suggested hypotheses and suggest that the TTFields effect on cell membrane potential by affecting ion channels could be a mechanism of tumor cell death. SIGNIFICANCE: Previously suggested mechanisms of tumor cell death from TTFields are found lacking. The effect of TTFields on the tumor cell membrane potential warrants further research. ncbi.nlm.nih.gov

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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 typeother

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureNot supplied

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

Numerical analysis found limited support for two previously proposed mechanisms: Brownian energy was several orders of magnitude larger than the TTFields-induced moment on tubulin dimers, and DEP-driven particle motion in cytoplasm was very slow (~0.003 μm/s) such that substantial effects would require sufficiently long telophase duration. Using the Schwan equation, fields at clinical TTFields frequencies were estimated to cause a 10%–17% change in tumor cell membrane potential.

Outcomes measured

Biophysical mechanisms during mitosis (microtubule assembly effects)
Dielectrophoretic (DEP) particle motion toward cleavage furrow
Tumor cell membrane potential changes (via Schwan equation)

Limitations

Theoretical/numerical analysis rather than experimental or clinical outcomes
Key effects (e.g., DEP impact) depend on assumptions such as telophase duration
No specific TTFields frequency, field strength, or exposure parameters reported in the abstract

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": "Tumor Treating Fields (TTFields)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Biophysical mechanisms during mitosis (microtubule assembly effects)",
    "Dielectrophoretic (DEP) particle motion toward cleavage furrow",
    "Tumor cell membrane potential changes (via Schwan equation)"
  ],
  "main_findings": "Numerical analysis found limited support for two previously proposed mechanisms: Brownian energy was several orders of magnitude larger than the TTFields-induced moment on tubulin dimers, and DEP-driven particle motion in cytoplasm was very slow (~0.003 μm/s) such that substantial effects would require sufficiently long telophase duration. Using the Schwan equation, fields at clinical TTFields frequencies were estimated to cause a 10%–17% change in tumor cell membrane potential.",
  "effect_direction": "unclear",
  "limitations": [
    "Theoretical/numerical analysis rather than experimental or clinical outcomes",
    "Key effects (e.g., DEP impact) depend on assumptions such as telophase duration",
    "No specific TTFields frequency, field strength, or exposure parameters reported in the abstract"
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "Tumor Treating Fields",
    "TTFields",
    "mitosis",
    "microtubules",
    "tubulin dimers",
    "dielectrophoresis",
    "DEP",
    "membrane potential",
    "Schwan equation",
    "ion channels"
  ],
  "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: 10.1109/tbme.2020.2965883
PubMed: Not supplied

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