Expression analysis of human HL60 cells exposed to 60 Hz square- or sine-wave magnetic fields.
A total of 960 complementary DNA (cDNA) clones from an HL60 cell cDNA library were screened to discover genes that were differentially expressed in HL60 cells exposed to 60 Hz square-wave magnetic fields (MFs) compared to sham-exposed cells. Square-wave fields are rich in odd harmonic frequency content. We used a two-gel cDNA library screening method (BIGEL) to identify treatment-induced alterations in gene expression. Four cDNA clones were tentatively identified as differentially expressed after exposure to square-wave MFs at 2 mT for 24 h. BIGEL-identified genes (GenBank accession number) corresponding to these clones were: TI227H (D50525), EST Homo sapiens partial cDNA (Z17814), human ribosomal protein S13 (L01124), and AICAR transformylase mRNAs (D82348). The differences in mRNA levels were not confirmed in test compared to experimental cells by Northern analysis. In other experiments, we used concurrent exposure to 60 Hz sine- or square-wave MFs (0 or 2 mT, duration of 3 or 24 h, no postexposure delay). In addition to the four BIGEL genes, we also investigated MYC, HSP70, RAN and SOD1. In the case of MYC and HSP70, square-wave MFs appeared to exhibit more marked alterations when compared to sinusoidal waveforms, but the overall results indicated no effect of possible differential magnetic-field-induced expression of all eight genes. In contrast, alterations of mRNA levels were observed for seven genes after exposure to X irradiation, hyperthermia and TPA. These results are contrary to previously proposed similarities between the action of these agents and MF effects on gene transcription.
Balcer-Kubiczek
E K
EK
Department of Radiation Oncology, Radiation Oncology Research Laboratories, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
Harrison
G H
GH
Davis
C C
CC
Haas
M L
ML
Koffman
B H
BH
D015152:Blotting, Northern; D002999:Clone Cells; D004574:Electromagnetic Fields / Q000009:adverse effects*; D020224:Expressed Sequence Tags; D015870:Gene Expression / Q000235:genetics / Q000528:radiation effects*; D020869:Gene Expression Profiling; D018922:HL-60 Cells; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D019877:Hydroxymethyl and Formyl Transferases / Q000096:biosynthesis / Q000235:genetics; D051027:Phosphoribosylaminoimidazolecarboxamide Formyltransferase; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000096:biosynthesis / Q000235:genetics; D013482:Superoxide Dismutase / Q000096:biosynthesis / Q000235:genetics; D000072105:Superoxide Dismutase-1; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014965:X-Rays; D020931:ran GTP-Binding Protein / Q000096:biosynthesis / Q000235:genetics
D018840:HSP70 Heat-Shock Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; C047013:RPS13 protein, human; D012269:Ribosomal Proteins; C000606290:SOD1 protein, human; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D019877:Hydroxymethyl and Formyl Transferases; D051027:Phosphoribosylaminoimidazolecarboxamide Formyltransferase; D020931:ran GTP-Binding Protein; D013755:Tetradecanoylphorbol Acetate