研究のタイプ: 医学/生物学の研究 (experimental study)

[亜鉛に共鳴させた低周波磁界へのばく露はがん細胞の成長を抑制する] med./bio.

Exposure to ELF magnetic field tuned to Zn inhibits growth of cancer cells.

掲載誌: Bioelectromagnetics 2005; 26 (8): 631-638

この研究は、特定の磁界パラメータのELF交番磁界が、p53存在が異なるいくつかのがん細胞の増殖に及ぼす影響を、細胞増殖アッセイを用いて調べた。実験に使用したがん細胞は、ヒトがん細胞HeLa(子宮がんp53(+/+))、Saos-2およびSaos-2-His-273(骨肉腫p53(-/-)およびp53 His-273変異体)、H1299tTAおよびH1299tTA- His175(肺がんp53(-/-)およびp53 His-175変異体)、および正常なヒト線維芽細胞VH-10(p53(+/+))である。ELF磁界は、周波数20 Hzの垂直交番磁界(ピークは38.7 μTまたは77.4 μT)と垂直静磁界(38 μT)の組み合わせ磁界である。水平静磁界はゼロであった。これらは、亜鉛イオンとの共鳴の第一次高調波として、レドネフの磁気パラメトリック共鳴(MPR)モデルまたはブランチャードとブラックマンのイオンパラメトリック共鳴(IPR)モデルから計算された。ELFばく露は72および96時間であった。PRIMA-1およびガンマ線による細胞の処理を陽性対照として用いた。その結果、IPRモデルで算出された38.7 μTの場合、細胞増殖阻害が観察され、HeLa、VH-10、およびSaos-2-His-273細胞の阻害は有意であった;MPRモデルで算出された77.4 μTの場合、一貫したELF効果は見られなかった; PRIMA-1は、すべての細胞株の成長を阻害し、変異体p53保有細胞株H1299tTA-His175で最も強い効果を示した;ガンマ線の影響は比較的弱かったことから、この研究で使用した細胞増殖アッセイの条件はアポトーシスに対する感度が低いことが示された;観察された増殖阻害とp53状態との関係は明確ではなかった、と報告している。

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研究目的(著者による)

To study the effects of extremely low frequency alternating magnetic fields tuned to Zn2+ (zinc ion) on the growth of cancer cells with different status of p53.

詳細情報

Almost all enzymes contain ions such as magnesium, calcium, and zinc, which are important for the stability of conformation of these proteins and their enzyme activity. According to several models, extremely low frequency magnetic fields affects cells through an influence on unhydrated ions inside proteins if parameters of exposure are tuned to these ions (see publication 257 and publication 2404).
One potential Zn2+-containing target for magnetic fields is the p53 protein. Binding of Zn2+ by p53 is required both for the conformation stability of p53 and for its sequence-specific DNA binding. Removal of Zn2+ abolishes DNA site-specific activity (and thus functionally inactivates p53).
It was investigated whether modulation of Zn2+ by extremely low frequency magnetic fields as based on IPR (ion parametric resonance model, see publication 2404) and MPR (magnetic parametric resonance model, see publication 1176) models can affect the growth of human cancer cells with different status of p53: wild type, deleted, mutant.
Treatments of cells with PRIMA-1 (p53 reactivation and induction of massive apoptosis; restores DNA-binding activity) and gamma rays were used as positive controls.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 20 Hz
ばく露時間: continuous for 72 und 96 h
  • 磁束密度: 43 µT (vertical static magnetic field)
  • 磁束密度: 38.7 µT peak (vertical alternating magnetic field)
ばく露2: 20 Hz
ばく露時間: continuous for 72 und 96 h.
  • 磁束密度: 43 µT (vertical static magnetic field)
  • 磁束密度: 77.4 µT peak (vertical alternating magnetic field)

ばく露1

主たる特性
周波数 20 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 72 und 96 h
ばく露装置
ばく露の発生源/構造
チャンバの詳細 Each ELF exposure unit was based on three orthogonal pairs of Helmholtz-circular coils, which produced relatively homogeneous (5%) magnetic fields inside the working volume. The vertical coils were oriented in the north-south direction.
ばく露装置の詳細 Exposures and sham exposures were performed simultaneously, using two identical ELF exposure units. In each experiment,exposure and sham exposure of four 96-well plates were simultaneously performed in identical Helmholtz coils under the same temperature, humidity, CO2 concentration, DC magnetic field, and background ELF magnetic field.
Additional information Treatments of cells with PRIMA-1 and gamma-rays were used as positive controls.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 43 µT - 測定値 - vertical static magnetic field
磁束密度 38.7 µT peak 測定値 - vertical alternating magnetic field

ばく露2

主たる特性
周波数 20 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 72 und 96 h.
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 43 µT - 測定値 - vertical static magnetic field
磁束密度 77.4 µT peak 測定値 - vertical alternating magnetic field

Reference articles

  • Belyaev IY et al. (2001): [E.coliとヒトの白血球でのクロマティンコンフォメーションに対する低周波磁界の周波数依存性]

ばく露を受けた生物:

方法 影響評価項目/測定パラメータ/方法

研究対象とした生物試料:
調査の時期:
  • ばく露後

研究の主なアウトカム(著者による)

Growth inhibition was revealed after exposure to extremely low frequency magnetic field at 38.7 µT. Inhibition of HeLa, VH10, and Saos-2-His-273 cells was statistically significant. No consistent extremely low frequency magnetic field effects following exposure at 77.4 µT were found.
PRIMA-1 inhibited the growth of all cell lines with the strongest effect in mutant p53-carrying cell line H1299tTA-His175. The effects of gamma-rays were relatively weak, indicating that the cell proliferation assay under conditions employed in this study is not very sensitive to apoptosis.
In conclusion, extremely low frequency magnetic field exposure tuned to Zn2+ (according to the IPR model) inhibited the growth of cancer and normal cells. No clear relationship of the revealed growth inhibition to p53 status was found.

研究の種別:

研究助成